An introductory and comprehensive review of complex diseases and their environmental influences. Using schizophrenia as an example, we are interested in exploring one of the biggest questions that underlie complex diseases. Go Back Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link The environment on complex diseases: schizophrenia Last updated: 01/03/26 Published: 08/05/23 An introductory and comprehensive review of complex diseases and their environmental influences. Using schizophrenia as an example, we are interested in exploring one of the biggest questions that underlie complex diseases. Introduction: Not Exactly a Yes or No Question Many things in science revolve around questions. It is remarkable to find the number of questions left for scientists to answer or those that will remain unanswered. Indeed, one of the most daunting tasks for any scientist would be to see through every detail of a piece of information, even if everyone has seen it, but with different sets of lenses and asking different sets of questions. After all, “why did the apple fall from its tree?”. However, asking questions is one thing. Finding answers and, more importantly, the evidence or proof that supports them does not always yield conclusive results. Nevertheless, perhaps some findings may shine a new light on a previously unanswered question. We can categorise the study of genetics into two questions: “What happens if everything goes well?” and “What happens if it goes wrong?”. Whilst there are virtually limitless potential causes of any genetic disease, most genetic diseases are known to be heritable. A mutation in one gene that causes a disease can be inherited from the parents to their offspring. Often, genetic diseases are associated with a fault in one gene, known as a single-gene disorder, with notorious names including Huntington’s disease, cystic fibrosis, sickle cell anaemia, and familial hypercholesterolaemia. These diseases have different mechanisms, and the causes are also diverse. But all these diseases have one thing in common: they are all caused by a mutation or fault in one gene, and inheriting any specific genes may lead to disease development. In other words, “either you have it, or you do not”. The role of DNA and mutations in complex diseases. Image/ craiyon.com Multifactorial or complex diseases are a classification geneticists give to diseases caused by factors, faults or mutations in more than one gene. In other words, a polygenic disease. As a result, the research, diagnosis, and identification of complex diseases may not always produce a clear “black-and-white” conclusion. Furthermore, complex diseases make up most non-infectious diseases known. The diseases associated with leading causes of mortality are, in their respective ways, complex. Household names include heart diseases, Alzheimer’s and dementia, cancer, diabetes, and stroke. All of these diseases may employ many mechanisms of action, involving multiple risk factors instead of direct cause and effect, using environmental and genetic interactions or factors to their advantage, and in contrast to single-gene disorders, do not always follow clear or specific patterns of inheritance and always involve more than one problematic genes before the complete symptoms manifest. For these reasons, complex diseases are infamously more common and even more challenging to study and treat than many other non-infectious diseases. No longer the easy “yes or no” question. The Complex Disease Conundrum: Schizophrenia Here we look at the case of a particularly infamous and, arguably, notorious complex disease, schizophrenia (SCZ). SCZ is a severely debilitating and chronic neurodevelopmental disorder that affects around 1% of the world’s population. Like many other complex diseases, SCZ is highly polygenic. The NHS characterise SCZ as a “disease that tends to run in families, but no single gene is known to be directly responsible…having these genes does not necessarily mean one will develop SCZ”. As previously mentioned, many intricate factors are at play behind complex diseases. In contrast, there is neither a single known cause for SCZ nor a cure. Additionally, despite its discovery a century ago, SCZ is arguably not well understood, giving a clue to the sophisticated mechanisms that underlie SCZ. To further illustrate how such complexities may pose a challenge to future medical treatments, we shall consider a conundrum that diseases like SCZ may impose. The highly elaborate nature of complex diseases means that it is impossible to predict disease outcomes or inheritance with absolute certainty nor rule out potential specific causes of diseases. One of the most crucial aspects of research on complex diseases is their genetic architecture, just as a house is arguably only as good as its blueprint. Therefore, a fundamental understanding of the genes behind diseases can lead to a better knowledge of diseases’ pathogenesis, epidemiology, and potential drug target, and hopefully, one day bridge our current healthcare with predictive and personalised medicine. However, as mentioned by the NHS, one of the intricacies behind SCZ is that possessing variants of diseased genes does not translate to certainty in disease development or symptom manifestation. Our conundrum, and perhaps the biggest question on complex diseases like SCZ is: “Why, even when an individual possesses characteristic genes of a complex disease, they may not necessarily exhibit symptoms or have the disease?”. The enigma surrounding complex diseases lies in the elegant interactions between our genes, the blueprint of life, and “everything else”. Understanding the interplay of factors behind complex diseases may finally explain many of the intricacies behind diseases like SCZ. Genes and Environment: an Obvious Interaction? The gene-environment important implications on complex disease development were demonstrated using twin studies. A twin study, as its name suggests, is the study of twins by their similarities, differences, and many other traits that twins may exhibit to provide clues to the influences of genetic and external factors. Monozygotic (MZ) twins each share the same genome and, therefore, are genetically identical. Therefore, if one twin shows a phenotype, the other twin would theoretically also have said genes and should exhibit the corresponding trait. Experimentally, we calculate the concordance rate, which means the probability of both twins expressing a phenotype or characteristic, given that one twin has said characteristic. Furthermore, the heritability score may be mathematically approximated using MZ concordance and the concordance between dizygotic twins (twins that share around half a genome). These studies are and have been particularly useful in demonstrating the exact implications genetic factors have on phenotypes and how the expression of traits may have been influenced by confounding factors. In the case of SCZ, scientists have seen, over decades, a relatively low concordance rate but high heritability score. A recent study (published in 2018) through the Danish SCZ research cohort involved the analysis of around 31,500 twins born between the years 1951 and 2000, where researchers reported a concordance rate of 33% and estimated heritability score of 79%, with other older studies reporting a concordance rate up to and around 50%. The percentages suggest that SCZ is likely to be passed down. In other words, a genetically identical twin only has approximately 1 in 2 risks of also developing symptoms of SCZ if its opposite twin also displays SCZ. The scientists concluded that although genetic predisposition significantly affects one’s susceptibility or vulnerability against SCZ, it is not the single cause of SCZ. Demographically, there have been studies that directly link environmental risks to SCZ. Some risk factors, such as famines and malnutrition, are more evident than others. However, some studies also associate higher SCZ risk among highly industrialised countries and first or second-generation migrants. For instance, few studies point out an increased risk of SCZ within ethnic minorities and Afro-Caribbean immigrants in the United Kingdom. Hypotheses that may explain such data include stress during migration, potential maternal malnutrition, and even exposure to diseases. With this example, hopefully, we all may appreciate how the aetiology of SCZ and other complex diseases are confounded by environmental factors. In addition, how such factors may profoundly influence an individual’s genome. SCZ is a clear example of how genetic predisposition, the presence of essential gene variants characteristic of a disease, may act as a blueprint to a terrible disease waiting to be “built” by certain factors as if they promote such development. It is remarkable how genetic elements and their interactions with many other factors may contribute almost collectively to disease pathogenesis. We can reflect this to a famous quote amongst clinical geneticists: “genetics loads the gun, and environment pulls the trigger.” Carrying high-risk genes may increase the susceptibility to a complex disease, and an environment that promotes such disease may tip the balance in favour of the disease. However, finding and understanding the “blueprints” of SCZ, what executes this “blueprint”, and how it works is still an area of ongoing research. Furthermore, how the interplay between genetics and external factors can lead to profound effects like disease outcomes is still a relatively new subject. The Epigenome: the Environment’s Playground To review, it is clear that genes are crucial in complex disease aetiology. In the case of SCZ, high-risk genes and variances are highly attributed to disease onset and pathogenesis. However, we also see with twin studies that genetics alone cannot explain the high degree of differences between twins, particularly when referring to SCZ concordance between identical twins. In other words, external factors are at play, influencing one’s susceptibility and predisposition to SCZ. These differences can be explained by the effects epigenetics have on our genome. Epigenetic mechanisms regulate gene expression by modifying the genome. In short, on top of the DNA double strands, the genome consists of additional proteins, factors, and even chemical compounds that all aid the genetic functions our body heavily relies on. The key to epigenetics lies in these external factors’ ability to regulate gene expression, where some factors may promote gene expression whilst others may prevent it. Epigenetic changes alter gene functions as they can turn gene expression “on” and “off”. Furthermore, many researchers have also shown how epigenetic changes may accumulate and be inherited somatically with cell division and even passed down through generations. Therefore, epigenetic changes may occur without the need to change any of the DNA codes, yet, they may cause a profound effect by controlling gene expression throughout many levels of the living system. These underlying mechanisms are crucial for the environment’s effect on complex diseases. Some external factors may directly cause variances or even damage to the genome (e.g. UV, ionising radiation), and other sources may indirectly change gene expression by manipulating epigenetic changes. The exact molecular genetics behind epigenetic mechanisms are elaborate. However, we can generally find three common epigenetic mechanisms: DNA Methylation, Histone Modification, and Non-coding RNA. Although each method works differently, they achieve a common goal of promoting or silencing gene expression. All of these are done by the many molecular components of epigenetics, altering the genome without editing the gene sequence. We refer to the epigenome, which translates to “above the genome”, the genome itself and all the epigenetic modifiers that regulates gene expression on many levels. Environmental factors and exposure may influence epigenetic mechanisms, affecting gene expression in the cell or throughout the body, sometimes permanently. Therefore, it is clear how the epigenome may change throughout life as different individuals are exposed to numerous environmental factors. Furthermore, each individual may also have a unique epigenome. Depending on which tissues or cells are affected by these mechanisms, tissues or cells may even have a distinct epigenome, unlike the genome, which is theoretically identical in all cells. One example of this is the potential effects of DNA methylation on schizophrenia epidemiology. DNA methylation can silence genes via the enzymes DNA methyltransferases (DNMT), a family of enzymes capable of catalysing the addition of methyl groups directly into the DNA. The DNMT enzymes may methylate specific nucleotides on the gene, which usually would silence said gene. Many researchers have found that the dysregulation of DNA methylation may increase the risk towards the aetiology of numerous early onset neuro-developmental disorders. However, SCZ later-onset development also points towards the influence of environmental risk factors that target DNA methylation mechanisms. Studies show links between famines and SCZ increased prevalence, as the DNMT enzymes heavily rely on nutrients to supply essential amino acids. Malnutrition is thought to play a considerable role in DNA methylation changes and, therefore, the risk of SCZ. Small Piece of a Changing Puzzle Hopefully, we can see a bigger picture of the highly intricate foundation beneath complex diseases. Bear in mind that SCZ is only one of many complex diseases known. SCZ is ultimately not a pristine and impartial model to study complex disorders. For instance, concordance rates of complex diseases change depending on their genetic background. In addition, they may involve different mutations, variance, or dysregulation of differing pathways and epigenetic mechanisms. After all, complex diseases are complex. Finally, this article aimed to give a rundown of the epigenetics behind complex diseases like SCZ. However, it is only a snapshot compared to the larger world of the epigenome. Furthermore, some questions remain unanswered: the genetic background and architecture of complex diseases, and ways to study, diagnose, and treat complex diseases. This Scientia article is one of the articles in Scientia on the theme of complex disease science and genetics. Hopefully, this introductory article is an insight and can be used to reflect upon, especially when tackling more complicated subjects of complex diseases and precision medicine. Written by Stephanus Steven Related articles: Schizophrenia, Inflammation, and Accelerated Ageing / An Introduction to Epigenetics

Psychology delves into the human mind and behaviour. Read on for compelling articles ranging from reward sensitivity to evolutionary, and empathy-altruism theories. Discover the psychology of emotions: embarrassment, and aggression. Psychology Articles Psychology delves into the human mind and behaviour. Read on for compelling articles ranging from reward sensitivity to evolutionary, and empathy-altruism theories. Discover the psychology of emotions: embarrassment, and aggression. You may also like: Biology, Medicine Motivating the mind Effect of socioeconomic status on reward sensitivity The evolutionary theory by Darwin vs empathy-altruism Explaining altruism through different theories A perspective on well-being Hedonic vs eudaimonic: based on the principles of Aristotle and Aristippus Nature vs. nurture in childhood intelligence What matters most? The psychology of embarrassment Why do we feel this emotion? Models and theories A primer on the Mutualism theory of intelligence A detailed review on different studies Unmasking aggression Is this fierce emotion the result of personal, or social triggers? Mental health strategies Raising awareness to look after mental health Imposter syndrome in STEM Have you ever had this feeling in your STEM education or job? Mental health in the South Asian community Why is it not yet such an open discussion? The cognitive orchestra How music can manipulate emotional processes The attentional blink An exploration of this concept in rapid serial visual presentation studies Postpartum depression in adolescent mothers An analysis of risk and protective factors Can we really 'rewire' our brain? What is neuroplasticity? The psychology of the halo effect Can looks influence the judgement of personality traits? Stockholm syndrome Why do some victims develop Stockholm syndrome and others don’t?

To begin, there was the Humoral Theory, which looked at how disease was caused by gaps in fluids/humours which were: blood, yellow bile, black bile and phlegm, which equated to the elements of air, fire, earth and water respectively. The imbalance can come from habits like overeating Go back Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Key historical events and theories in public health Last updated: 01/03/26 Published: 10/02/23 Introduction Now more than ever, public health has become crucial, which looks at promoting health and preventing disease within a society. There have been numerous events and concepts that have helped shape our current health systems today because without them, it is possible that our health systems would not have advanced without previous knowledge to evolve from. This article will focus on certain key events and concepts. Humoral Theory (Ancient Greek and Roman times) To begin, there was the Humoral Theory, which looked at how disease was caused by gaps in fluids/humours which were: blood, yellow bile, black bile and phlegm, which equated to the elements of air, fire, earth and water respectively. The imbalance can come from habits like overeating and too little/much exercise or external factors such as the weather. This theory was thought to have originated from the Hippocratic Corpus, a compilation of 60 medical documents written during the Ancient Greek era by Hippocrates. Although this theory as we know now is flawed, it did provide a foundational understanding of the human body and was utilised in public health for centuries before being subsequently discredited for the Germ Theory established during the mid-19th century. Miasma Theory (Ancient Greek era to the 19th century) Another theory replaced by Germ Theory was the Miasma theory, which stated that diseases like the plague and cholera were spread due to toxic vapours from the ground/decomposing matter. This theory along with the Humoral theory was accepted for thousands of years since the Ancient Greek era. With regards to the cholera outbreaks in the Victorian era, John Snow’s theory of polluted water causing cholera was initially not accepted by the scientific community during his death in 1858. Eventually though, his theory became accepted when Joseph Bazalgette worked to fix London’s sewage to prevent more deaths by cholera. This event with the Germ Theory led to Miasma and Humoral theories to be disproved, although they provided foundational understanding of how diseases spread. The discovery of vaccines (late 18th century) Aside from theories such as the four humors from above, there were concepts or discoveries that advanced public health measures such as vaccination, which eradicated smallpox and is still used today to prevent the severity of diseases such as COVID-19, influenza and polio. The origins of successful vaccines could be traced back to Edward Jenner who in 1796, retrieved samples from cowpox lesions from a milkmaid because he noticed that contracting cowpox protected against smallpox. With this in mind, he inoculated an 8 year old boy and after this, the boy developed mild symptoms, but then became better. Without this event, it is likely that the human population would significantly decrease as there is more vulnerability to infectious diseases and public health systems being weaker or less stable. Image of a COVID-19 injection. Germ Theory (19th century) As for current scientific theories relating to public health, there is the widely accepted Germ Theory by Robert Koch during the 19th century in the 1860s, stating that microorganisms can cause diseases. He established this theory by looking at cow’s blood through a microscope to see that they died from anthrax and observed rod-shaped bacteria with his hypothesis that they caused anthrax. To test this, he infected mice with blood from the cows and the mice also developed anthrax. After these tests, he developed postulates and even though there are limitations to his postulates at the time like not taking into account prions or that certain bacteria do not satisfy the postulates, they are vital to the field of microbiology, in turn making them important to public health. The establishment of modern epidemiology (19th century) Another key concept for public health is epidemiology, which is the study of the factors as well as distribution of chronic and infectious diseases within populations. One of epidemiology’s key figures is John Snow, who explored the cholera epidemics in London 1854, where he discovered that contaminated water from specific water pumps was the source of the outbreaks. Moreover, John Snow’s work on cholera earned him the title of the “father of modern epidemiology” along with his work providing a basic understanding of cholera. Therefore, this event among others has paved the way for health systems to become more robust in controlling outbreaks such as influenza and measles. Conclusion Looking at the key events above, it is evident that each of them has played an essential role in building the public health systems today through the contributions of the scientists. However, public health, like any other science, is constantly evolving and there are still more future advancements to look forward to that can increase health knowledge. Written by Sam Jarada Related articles: Are pandemics becoming less severe? / Rare zoonotic diseases / How bioinformatics helped with COVID-19 vaccines REFERENCES Lagay F. The Legacy of Humoral Medicine. AMA Journal of Ethics. 2002 Jul 1;4(7). Earle R. Humoralism and the colonial body. Earle R, editor. Cambridge University Press. Cambridge: Cambridge University Press; 2012. Halliday S. Death and miasma in Victorian London: an obstinate belief. BMJ. 2001 Dec 22;323(7327):1469–71. Riedel S. Edward Jenner and the history of smallpox and vaccination. Proceedings (Baylor University Medical Center). 2005 Jan 18;18(1):21. National Research Council (US) Committee to Update Science, Medicine, and Animals. A Theory of Germs. Nih.gov. National Academies Press (US); 2017. Sagar Aryal. Robert Koch and Koch’s Postulates. Microbiology Notes. 2022. Tulchinsky TH. John Snow, Cholera, the Broad Street Pump; Waterborne Diseases Then and Now. National Library of Medicine. Elsevier; 2018. p. 77–99.

In particular the novel zeolitic 2-methylimidazole framework (ZIF-8) MOF has received attention for drug delivery. ZIF-8 is composed of Zn2+ ions and 2-methylimidazole ligands, making a highly crystalline structure. ZIF-8 MOFs are able to deliver  cancer drugs like doxorubicin to tumorous environments as it possesses a pH-sensitive degradation property. ZIF-8’s framework will only degrade in pH 5.0-5.5 which is a cancerous pH environment, and will not degrade in normal human body pH 7.4 Go back Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link How metal organic frameworks are used to deliver cancer drugs in the body Last updated: 01/03/26 Published: 20/04/23 In late 2025, the Nobel Prize in Chemistry was awarded to Susumu Kitagawa, Richard Robson and Omar M. Yaghi for their pioneering work in developing metal-organic frameworks (MOFs). Metal ions and organic ligands are able to connect to form metallic organic frameworks on a nanoscale (Nano-MOFs) for cancer drug delivery. Metal Organic Frameworks (MOFs) are promising nanocarriers for the encapsulation of cancer drugs for drug delivery in the body. Cancer affects people globally with chemotherapy remaining the most frequent treatment approach. However, chemotherapy is non-specific, being cytotoxic to patients’ normal DNA cells causing severe side effects. Nanoscale Metal Organic Frameworks (Nano-MOFs) are highly effective for encapsulating cancer drugs for controlled drug delivery, acting as capsules that deliver cancer drugs to only tumorous environments. MOFs are composed of metal ions linked by organic ligands creating a permanent porous network. MOFs are able to form one-, two-, or three-dimensional structures building a coordination network with cross-links. When synthesized MOFs are crystalline compound and can sometimes be observed as a cubic structure when observed on a scanning electron microscope (SEM) image. In particular the novel zeolitic 2-methylimidazole framework (ZIF-8) MOF has received attention for drug delivery. ZIF-8 is composed of Zn2+ ions and 2-methylimidazole ligands, making a highly crystalline structure. ZIF-8 MOFs are able to deliver cancer drugs like doxorubicin to tumorous environments as it possesses a pH-sensitive degradation property. ZIF-8’s framework will only degrade in pH 5.0-5.5 which is a cancerous pH environment, and will not degrade in normal human body pH 7.4 conditions. This increases therapeutic efficacy for the patients having less systemic side effects, an aspect that nanomedicine has been extensively researching. As chemotherapy will damage health DNA cells as well as cancer cells, MOFs will only target cancer cells. Additionally the ZIF-8 MOF has a high porosity property due to the MOFs structures that is able to uptake doxorubicin successfully. Zn2+ is used in the medical field having a low toxicity and good biocompatibility. Overall MOFs and metal-organic molecules are important for the advancement of nanotechnology and nanomedicine. MOFs are highly beneficial for cancer research being a less toxic treatment method for patients. ZIF-8 MOFs are a way forward for biotechnology and pharmaceutical companies that research treatments that are more tolerable for patients. Such research shows the diversity of chemistry as the uses of metals and organic molecules are able to expand to medicine. Written by Alice Davey Related article: Anti-cancer metal compounds

Global warming can lead to higher transmission rates of dengue fever Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link The impacts of global warming on dengue fever Last updated: 08/10/25, 17:42 Published: 19/06/25, 08:00 Global warming can lead to higher transmission rates of dengue fever Introduction Dengue fever is a viral disease transmitted by two mosquitoes: Aedes aegypti and Aedes albopictus . These mosquitoes are called ‘vectors’. Symptoms of dengue fever include a sudden high fever and severe headaches, making it hard to diagnose. Transmission suitability is endemic, meaning the virus spreads where the conditions are suitable for the vectors to survive and reproduce for 10-12 months. This disease is endemic in the tropics, including much of Sub-Saharan Africa and Central Africa, Northern South America, Brazil, South and Southeast Asia, and parts of Northern Australia. The World Health Organisation (WHO) has stated that it is “the most important mosquito-borne viral disease in the world”. Dengue fever does not currently have a vaccine. There are many areas of transmission, and dengue fever impacts communities worse if they have weaker health systems. Severe dengue can be fatal, especially in children, who have a weaker immune system. Due to climate change and increasing temperatures, more areas will be habitable for the vectors in the future. This could lead to higher transmission rates of dengue fever. Researchers used a modelling approach using different datasets to make projections of the impact of changing temperatures and predict the future spread of dengue fever. They specifically looked at locations and months suitable for dengue transmission if conditions were suitable for both vectors. Method The researchers used temperature data from the Berkeley Earth Surface Temperatures dataset for the present day (2001-2020). They also used projected temperature data for 2050 based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) projections for the socio-economic pathway (SSP) 1-2.6 scenario and SSP5-8.5 scenario, as used in the Intergovernmental Panel on Climate Change Sixth Assessment Report. The SSP1-2.6 scenario is the best-case scenario and assumes international policy agreements and emissions reductions will be followed, limiting the average global temperature to 1.5 °C above pre-industrial levels. The SSP5-8.5 scenario is the “business as usual” scenario and assumes that continued fossil fuel use and development will occur. Researchers used the most recent climate projections from the CMIP6, which gave an up-to-date, holistic view of the impact of potential differences between climate change trajectories on vulnerable populations. This information can be used to support climate change mitigation strategies and disease prevention and control. Thermal limits for the mosquito vectors used in this study were 19.9 - 29.4 °C for Aedes aegypti and 21.3 - 34 °C for Aedes albopictus , since the vectors can only survive and reproduce within these temperatures. Modelling the thermal limits of both vectors, instead of just one, made the analysis more comprehensive. The researchers also applied an aridity mask using the Normalised Difference Vegetation Index (NDVI), which excluded areas too dry for mosquito survival and reproduction. They then applied the thermal limits and aridity mask to the climate data to predict areas with suitable conditions for the vectors and estimate the number of months suitable for transmission. Using aridity masks (previously only done with malaria) enhanced the model's accuracy because moisture is an important factor for mosquito breeding. Results Figure 1 shows that under the SSP1-2.6 (best-case) scenario, there will be new suitability for dengue transmission in temperate regions by 2050, lasting about 1 to 2 months. In addition, northwestern South America could see increases of up to 5 months of new suitability, and Eastern Africa up to 6 months of new suitability. In addition, eastern and southern Central America, central and northwestern South America, northern Australia, and parts of Southeast Asia are also becoming suitable for year-round transmission. Figure 2 shows that under the SSP5-8.5 (“business as usual”) scenario, areas will become suitable for year-round transmission in similar locations as under the SSP1-2.6 scenario by 2050. Dengue transmission suitability could increase by up to 6 months in Eastern Africa, and up to 10 months in parts of northwestern South America. Areas as far north as the Arctic Circle also have new suitability under this scenario. This demonstrates that climate change could result in the expansion of areas and the length of time during which dengue fever transmission is possible. Evaluation It’s essential to also acknowledge the study's limitations. For example, the model did not account for other variables impacting disease transmission, such as mosquito adaptation and extreme weather. The potential adaptation of mosquitoes and parasites to changing environmental conditions could alter transmission dynamics. In addition, extreme weather events, such as heavy rain, could eliminate breeding sites. Furthermore, the method of using modelling and projections is unreliable, because many things could change between now and 2050. For example, there could be temperature fluctuations, or temperatures could fall between SSP1-2.6 and SSP5-8.5, rather than being fixed in either scenario. This could affect the reliability of predicting future dengue fever transmission suitability. The study also did not include aridity projections under climate change scenarios. As future projections of NDVI are not currently available, NDVI values for 2020 were held constant for the 2050 projections. There will likely be changes in aridity by 2050, which will affect mosquito reproduction and dengue transmission. Nevertheless, this study's results are still important because they suggest that with increasing climate change, dengue fever transmission could increase, which would be a public health issue. Further listening and reading If you would like to know more about dengue fever, consider listening to this short 5-minute podcast from the World Health Organisation. If you would like to know more about the impacts of climate change on health, consider listening to this podcast , also from the World Health Organisation. If you would like to know more about the impacts of climate change on neglected tropical diseases (NTDs), consider reading the full open-access paper mentioned in this article . Written by Naoshin Haque Related articles: Potential vaccine for malaria / Correlation between HDI and mortality rate / Healthcare challenges during civil war in Sudan / Rising temperatures impacts Project Gallery

Knowing which species menstruate lets us pick suitable animal models Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Do other animals get periods? Last updated: 29/03/26, 16:48 Published: 26/06/25, 08:00 Knowing which species menstruate lets us pick suitable animal models Periods, formally called menstruation, happen to female mammals every menstrual cycle when an egg cell is not fertilised. Levels of the progesterone hormone decrease, causing the lining of the uterus to self-destruct and shed. This lining is called the endometrium and is flushed out of the body with blood during menstruation. Some primates, bats, the spiny mouse, and elephant shrews get periods ( Figure 1 ). Since these groups are distantly related, menstruation likely evolved multiple times independently. Knowing which species menstruate lets us pick animal models which best reflect the human female reproductive system. Why do we get periods? Despite being painful and inconvenient, menstruation must have some benefit; otherwise, natural selection would not favour it on multiple separate occasions. Hypotheses put forward to explain menstruation include clearing the uterus of pathogens and saving energy compared to maintaining an endometrium all the time. A 2012 paper argues that neither of these hypotheses are true and that menstruation is an unfortunate byproduct of the way pregnancy occurs in certain animals. A more recent article expands on this idea; menstruation was not selected for in isolation, rather it evolved as one small part of a complex reproductive system. In non-menstruating animals, an embryo induces morphological and biological changes in the uterus, so those changes do not happen if they are not pregnant. The uterus of a menstruating animal undergoes regular changes even without an embryo, and one of those changes is shedding the endometrium. However, there is no consensus on the benefits of menstruation. Non-human primates Old World monkeys, apes, and humans menstruate conspicuously. This could be because their endometria have spiral arteries, which dilate and weaken in response to hormones. Eventually, the weakened arteries break and release blood, which carries dead and detached endometrial tissue out of the body. While chimpanzee menstruation is visible to the naked eye, menstrual blood in orangutans and gorillas is detected with a chemical urine strip. Gorillas bleed for 3 days, while orangutans bleed for 1-4 days. Humans have the most obvious, and possibly the most prolonged, menstruation out of the Old World primates. (Aren’t we unlucky?). On the other hand, the very few New World monkey species which menstruate need a microscope to detect it. Pedro Mayor and colleagues sampled the endometria of various New World monkeys and viewed those samples under a microscope. They found that monkeys from the Aotus nancymaae and Sapajus macrocephalus species had weakened endometria with dilated blood vessels and blood clots ( Figure 2 ). Combined with other context clues from those endometrium samples, they concluded that those monkeys must be menstruating. Bats Microscopy also identified menstruation in some bat species. In a 2011 study, uterus sections from Carollia perspicillata bats showed the endometrium getting thinner over a few days with associated bleeding. Some sections had endometrial debris in the lumen of the uterus – but unlike in Old World primates and humans, this debris was reabsorbed by the body rather than released. Menstruating Molossus ater bats had blood and endometrial cells in their cervix under a microscope, while one individual was visibly bleeding in its vagina. In contrast, a colony of female Rousettus leschenaulti bats all had visible vaginal bleeding on the same day. On that day, two-thirds of their endometria were shed, and they had low progesterone levels – meaning those bats were menstruating. Bat menstruation differs from primates in at least two ways. Firstly, menstruation happens simultaneously with ovary development in Carollia perspicillata and before ovary development in primates. Secondly, some bat species only menstruate after an interrupted mating attempt – which scientists call coitus , and the public would call “pulling out”. Perhaps menstruation gives these bats a second chance at successful mating in that breeding season. Conclusion We rarely see other animals on their period because if the species does menstruate, they do not bleed as much as humans do. Evidence of menstruation in New World monkeys and bats usually came from microscopy, where the endometrium was seen to detach, and blood was seen in the uterine lumen. These monkeys and bats could be used as rudimentary animal models to study what happens in humans during a period. Written by Simran Patel Related article: Monkey see, monkey clone REFERENCES Catalini L, Fedder J. Characteristics of the endometrium in menstruating species: lessons learned from the animal kingdom. Biology of Reproduction [Internet]. 2020 May 26 [cited 2025 Jan 8];102(6):1160–9. Available from: https://doi.org/10.1093/biolre/ioaa029 Mayor P, Pereira W, Nacher V, Navarro M, Monteiro FOB, El Bizri HR, et al. Menstrual cycle in four New World primates: Poeppig’s woolly monkey (Lagothrix poeppigii), red uakari (Cacajao calvus), large-headed capuchin (Sapajus macrocephalus) and nocturnal monkey (Aotus nancymaae). Theriogenology [Internet]. 2019 Jan 1 [cited 2025 Jan 7];123:11–21. Available from: https://www.sciencedirect.com/science/article/pii/S0093691X18302796 Rasweiler IV JJ, Badwaik NK, Mechineni KV. Ovulation, Fertilization, and Early Embryonic Development in the Menstruating Fruit Bat, Carollia perspicillata. The Anatomical Record [Internet]. 2011 [cited 2025 Jan 8];294(3):506–19. 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Psilocybin's active metabolite, psilocin, acts as a serotonin receptor agonist Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link The promising effects of magic mushrooms for depression Last updated: 05/04/26, 15:37 Published: 19/02/26, 08:00 Psilocybin's active metabolite, psilocin, acts as a serotonin receptor agonist This is Article 3 in a series on psychiatric disorders and the brain. Previous article: Inside out: the chemistry of depression . Next article coming soon. What is psilocybin? Psilocybin is a naturally occurring psychedelic tryptamine alkaloid found in over 200 species of mushrooms (Psilocybin mushrooms), commonly known as magic mushrooms or shrooms. Upon ingestion, the body converts psilocybin into its active metabolite, psilocin, which acts as a serotonin receptor agonist, primarily impacting 5-HT2A receptors. What is psilocybin useful for? In recent years, clinical research has shown that psilocybin-assisted therapy, can quickly and meaningfully reduce symptoms of depression, often within days rather than weeks, when given in a safe, controlled medical setting with psychological support. Importantly, these studies don’t just look at mood while someone is under the influence. They measure long-term changes weeks or months after treatment. Studies, such as Gukasyan et al. , 2022 and Goodwin et al. , 2022, have shown that 1-2 doses of psilocybin plus therapy have led to sustained reductions in depressive symptoms that last at least 8-12 weeks, and in some cases 12 months later. Research has also demonstrated potential benefits for individuals whose depression has not responded to conventional antidepressant treatments. A large phase II double-blinded trial, by Griffiths et al. , 2016, involving people with treatment-resistant depression found that those given a therapeutic dose (25 mg) of psilocybin had noticeably greater improvement in their depression scores compared with a very low dose (10 mg). Scientists, for example Daws et al. , 2022, believe psilocybin works differently from standard antidepressants. It appears to temporarily increase connections between different parts of the brain and may help break rigid patterns of negative thinking that are typical in depression. If psilocybin is effective, why is it not currently used in treatment for depression? Psilocybin remains classified as a Schedule I controlled substance under the United Nations 1971 Convention on Psychotropic Substances, meaning it is considered to have a high potential for abuse and no accepted medical use. For psilocybin to become an approved clinical treatment for depression, it must be rescheduled through formal regulatory review, a process that involves extensive clinical testing and bureaucratic steps. In many countries, including the United States, rescheduling controlled substances can be slow and complex. For example, in 2022-2023, the U.S. government reviewed the scheduling of marijuana (cannabis) after presidential direction to federal agencies, but a final rescheduling decision was still pending as of late 2025. According to the U.S. Drug Enforcement Administration, Schedule III drugs are defined as substances with moderate to low potential for physical and psychological dependence, whereas Schedule I substances are defined as having no currently accepted medical use and a high potential for abuse. Because psilocybin is still Schedule I in most jurisdictions, it cannot yet be prescribed as a mainstream treatment for depression, despite promising clinical trial results. Written by Chloe Kam Related article: What does depression do to your brain? Project Gallery

Beyond sugarcane fields and dreamy beaches, Mauritius secures first place in mobile connectivity Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Mauritius's rise as African leader of mobile networks Last updated: 11/04/26, 16:04 Published: 05/06/25, 08:00 Beyond sugarcane fields and dreamy beaches, Mauritius secures first place in mobile connectivity Background: GSMA ranking In the bustling capital city of Port Louis, commuters check the latest news updates using mobile data on their phones. Across the busy, connecting streets, a handful of tourists video call their family back home, asking them what souvenirs they would like- also on mobile data. Apart from idyllic holiday scenes and solid sugar exports, the island nation of Mauritius has become number one in Africa for mobile connectivity- as scored by the Global System for Mobile Communications Association (GSMA). The small island is now at the forefront of telecommunication development, with the increasing rollout of 5G networks. How did this touristic country become a leader in mobile connectivity? On the 13th of August 2024, the GSMA announced its yearly index for mobile connectivity. The GSMA looks at 41 African countries and ranks them based on: internet accessibility, prices of mobile devices, relevant services and political environments. Scoring 62.7 points out of the possible 100, Mauritius took the first spot, in front of South Africa. This result also places the island country 76th in the world. Remarkably, this is the third consecutive year that Mauritius is leading in mobile connectivity in Africa. Moreover Mauritius, with a population of 1.26 million, boasts an average of 1.7 phones per person, compared to only 1.2 phones per person in the US (according to 2023 data). Connecting the island: 5G is nearly everywhere Three companies provide mobile phone networks on Mauritius island: Emtel, MTML (Chili) and state-owned My.t. At present, 5G is widely available in Mauritius, thanks to Emtel supplying it to approximately 80% of the island for both residential and commercial usage. Though Emtel is the biggest network in the country, My.t is the most popular provider currently, and it also offers 5G to its users. A closer look at 4G and 5G 3G (and 3G High-Speed Packet Access, HSPA), 4G (Long Term Evolution, LTE) and 5G are wireless mobile networks, where the ‘G’ in these networks means ‘generation’ and indicates the strength of the signal on the mobile device. Hence, each mobile network is an improvement since the last generation of network. These mobile networks aim for high quality, reliable communication, and are based on radio signals. Each generation has evolved to achieve this. Table 1 compares the differences between all of these networks. The original 1G network from 1979 used analogue radio signals, while subsequent network generations use digital radio signals. Table 1: A comparison of 2G, 3G, 4G and 5G mobile networks 2G 3G HSPA+ 4G LTE 5G Speed 64Kbps 8Mbps 50Mbps 10Gbps Bandwidth 30- 200 kHz 15- 20 MHz 100 MHz 30- 300 GHz Features Better quality video calls than before Can send and receive larger emails Higher speeds and capacities Much faster speeds and capacities; high resolution video streaming SMS and MMS Larger capacities Low cost per bit Low latency Interactive multimedia, voice, video Allows remote control of operations e.g. vehicles, robots, medical procedures It is evident from Table 1 that not only have speeds and capacities increased with each generation, but new features have also been implemented such as video calls, interactive multimedia, streaming, and remote control of operations. Introduced in 2019, 5G is thought to be the most ambitious mobile phone network- almost revolutionary in its benefits since 1G. Usually, mobile carriers operate on a 4G LTE and 5G coexistence. This means that 5G phones can switch to 4G if 5G isn’t available in the region. Top of the tower- how? Since the 5G rollout in 2021, Mauritius has been enjoying the larger capacities and speeds of the network. The same question arises: how did this touristic country become a leader in mobile connectivity? There are several factors: - Tourist hotspot - Government initiatives - Improving local infrastructure - General advancements in mobile network technologies - High penetration rates and mobile ownership - Increasing number of connections - Geography Each factor will be considered in turn. Factor 1- Tourist hotspot Every year, Mauritius attracts visitors far and wide to enjoy its mesmerising beaches, luscious escapes and tantalising wildlife. Therefore, over time, mobile network technology has had to improve to meet the communicative needs of tourists. Put differently, tourism significantly supports the telecom industry on the island. Factor 2- Government initiatives As well as providing free, public WiFi hotspots around the island, the government is committed to bridging the digital divide and increasing access to all of its population. Thus, it was announced that, eligible citizens between the ages of 18 and 25 will receive a free, monthly mobile data package (with 4G and 5G capabilities)- starting from the 1st of September 2024. It is an endeavour to include young people in the government’s digital plans, i.e. digital inclusion. Factor 3- Improvements in local infrastructure In recent years, My.t and EmTel have been upgrading their equipment to ensure better coverage and access to 5G in the country. Infrastructure must have improved so that the three mobile operators on the island were granted the license for 5G rollout in June 2021. The current goal is to fully expand 5G coverage in Mauritius. Factor 4- General advancements in mobile network technologies Since its inception in 2019, 5G has had a profound impact on consumers around the globe with its low latency, high resolution streaming, and insanely high speeds and capacities. This pioneering mobile network has rolled out to millions of people, including the citizens of Mauritius island. The government has utilised this new technology to empower its people and pave a way for the country to become a leader in mobile connectivity. Factor 5- High penetration rates and mobile ownership Early 2025 data shows that the East African nation has over 2.1 million active mobile connections, when its population is half of that, a mere 1.261 million. (More mobile connections is not an usual thing as people may have separate connections for personal and work use, for example. Embedded SIMs – eSIMs- have made this possible recently). With this statistic, Mauritius has a high degree of mobile ownership and network connection density. Factor 6- An increase in the number of connections Another recent event is that the number of mobile connections in the nation has been increasing gradually: between 2024 and 2025, the number has increased by 1.9%. Factor 7- Geography It is known that less land- especially less rural land- makes deployment of cell phone towers and installation of masts much easier. Therefore, spanning an area of 2,040 squared kilometres, the main island of Mauritius can enjoy adequate mobile coverage- being one of the smallest African countries. Small island, big signal. To summarise, the above factors contribute to the number one ranking in mobile connectivity for Mauritius. What does Mauritius’s rise mean for the future? If these advancements in infrastructure and technology continue on the island, then there is a brighter outlook for the future. 5G coverage in Mauritius is on its way to completion, ensuring all districts have access to the latest mobile network. Geography, government initiatives, improvements in infrastructure by mobile operators, high number of mobile connections and ownership, are some of the factors that enabled 5G rollout in Mauritius in the first instance. Mauritius is leading by example to the other countries in Africa and is additionally performing well on the global stage for mobile networks. This small island country, usually known for its exotic sights and sugarcane landscape, is quickly overtaking its African neighbours in the race to become the leader in mobile phone connectivity. Written by Manisha Halkhoree Related articles: The future of semiconductor manufacturing / Wireless electricity Project Gallery

Pushing the boundaries of analytical chemistry Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link Advances in mass spectrometry technology 05/06/26, 21:29 Last updated: Published: 09/06/24, 11:48 Pushing the boundaries of analytical chemistry In the rapidly evolving field of analytical chemistry, recent technological innovations in mass spectrometry have revolutionised the analysis and characterisation of molecules. These advancements, including high-resolution mass analysers, ion mobility spectrometry (IMS), and ambient ionisation techniques, are pushing the boundaries of what can be achieved in chemical analysis. Mass spectrometry is a powerful analytical technique that provides qualitative and quantitative information on an analyte. It is useful for measuring the mass-to-charge ratio (m/z) of one or more molecules present in a sample. The process consists of: Inlet - Allows the analyte to be connected to the mass spectrometre (MS). Could be direct inlet or gas chromotography (GC) / liquid chromatography (LC) to allow some separation before MS Ion source - Ensures that the analyte is ionised (i.e. carries a net charge) there are various types of ion sources depending on the analyte Analysers - Brings about a change in the velocity/trajectory of an ion from which the ions m/z can be determined i.e. characterises rate/velocity of ion. Multiple analysers are in tandem and different analysers can be combined to allow greater scope for analysis. A detection system is also required to amplify and measure ion signals. Analysers and detectors need to be held under low pressure - near vacuum. Detector - collects charge signals from ion beams. The computer then detects a spectrum. The electronic signals from the ions are then digitised to produce a mass spectrum of the analyte. High-resolution mass analysers One of the most significant breakthroughs in mass spectrometry is the development of high-resolution mass analysers. These instruments can differentiate between ions with extremely close mass-to-charge ratios, providing unprecedented levels of accuracy and specificity in compound identification. High-resolution mass spectrometry enables scientists to resolve complex mixtures and detect trace components with exceptional sensitivity, making it invaluable in fields such as metabolomics, environmental analysis, and drug discovery. Ion Mobility Spectrometry (IMS) Ion mobility spectrometry is another cutting-edge technology that enhances the capabilities of mass spectrometry. IMS separates ions based on their size, shape, and charge in the gas phase, providing an additional dimension of separation before mass analysis. This technique improves the resolution of complex samples, particularly for isomeric compounds that are challenging to distinguish using conventional methods. IMS coupled with mass spectrometry is widely applied in metabolomics, proteomics, and lipidomics research, enabling deeper insights into molecular structures and interactions. Ambient ionisation techniques Traditional mass spectrometry methods often require extensive sample preparation and ionisation processes in controlled laboratory environments. Ambient ionisation techniques have transformed this paradigm by enabling direct analysis of samples in their native states, including solids, liquids, and gases, without prior extraction or purification steps. Techniques such as desorption electrospray ionisation (DESI) and direct analysis in real-time (DART) have expanded the scope of mass spectrometry applications to fields like clinical diagnostics, food safety, and forensic analysis. Ambient ionisation allows for rapid, on-site measurements with minimal sample handling, revolutionising point-of-care testing and field analysis. In conclusion, the continuous evolution of mass spectrometry technology is reshaping the landscape of analytical chemistry. These innovations not only empower researchers to explore new realms of chemical analysis but also facilitate applications in areas such as precision medicine, environmental monitoring, and materials science. As these technologies continue to advance, the future holds even greater promise for pushing the boundaries of analytical chemistry and unlocking the mysteries of the molecular world. Written by Anam Ahmed Related articles: Advancements in semi-conductor manufacturing / Inorganic NMR Project Gallery

Launched in 2021, James Webb Space Telescope (JWST) is an astronomical observatory, designed to explore and observe the universe beyond the capabilities of its predecessor, the Hubble telescope. The JWST has primary mirror of 6.5m in diameter, the largest of any space-based telescope, and its advanced infrared technology, it can observe objects that were previously too faint, old, and distant for the Hubble telescope. Go back Facebook X (Twitter) WhatsApp LinkedIn Pinterest Copy link James Webb Space Telescope: A Breakthrough in Space Exploration Last updated: 01/03/26 Published: 25/03/23 Launched in 2021, James Webb Space Telescope (JWST) is an astronomical observatory, designed to explore and observe the universe beyond the capabilities of its predecessor, the Hubble telescope. The JWST has a primary mirror of 6.5m in diameter, the largest of any space-based telescope; and with its advanced infrared technology, it can observe objects that were previously too faint, old, and distant for the Hubble telescope. The JWST’s aim is to revolutionise the exploration of the cosmos by studying the earliest galaxies and stars, and to detect light from the first objects that were formed in the universe. In its short deployment time, the JWST has already provided us with fascinating new insights and images of the deep space, pushing the boundaries of our understanding of the cosmos. History of James Webb Space Telescope • 1996: Next Generation Space Telescope project first proposed (8m) • 2001: NEXUS Space Telescope, a precursor to the Next Generation Space Telescope, cancelled • 2002: Proposed project renamed James Webb Space Telescope, (mirror size reduced to 6 m) • 2003: Northrop Grumman awarded contract to build telescope • 2007: Memorandum of Understanding signed between NASA and ESA[72] • 2010: Mission Critical Design Review (MCDR) passed • 2011: Proposed cancellation • 2016: Final assembly completed • 2021: Launch Achievements of James Webb Space Telescope In its short deployment, the JWST has been able to provide some exceptional data, ranging from beautiful pictures of galaxies and nebulas, the first of its kind image of an exo planet and details of exo planets atmosphere. Since its launch, scientists have been discovering galaxies far away and older than ever before, the launch of this observatory has truly made a breakthrough in space exploration. Some of its achievements are explained more in detail below: • To begin with, the JWST has been able to capture some of the most breath-taking and beautiful images of nebulae and galaxies, in both visible light and infrared spectrum. The new pictures have changed the way we had observed these subjects, giving us a deeper insight into the formation stars in these nebulae due to its higher resolutions. Some of the most iconic pictures from the JWST so far have been the pictures of the pillars of creation and the southern ring nebula. • Studying exoplanets have always been a challenge for scientists, as due to their size exoplanets are only visible through analysis of dips in luminance of its host star. But for the first time, the JWST using its infrared spectrometer and primary lens, was able to capture an image of an exoplanet directly. • During its observations, the JWST has been able to study and explore many star systems and in some cases, the exoplanets as well- going as far as studying their atmospheres in some detail, giving the research teams an insight into what these worlds may look like. • The JWST, while observing the deep space, has been able to capture the oldest galaxies known to mankind, dated as old as 13.4 billion years, 350 million years after the Big Bang. Future of Space Exploration and JWST The launch of the JWST marks a significant milestone in the field of space exploration. Not only has it opened up a new era of scientific discovery, but it has also introduced a new era for large space structures. The JWST, being the first self-assembling telescope launched in space, has proven that the only viable option for launching such a massive instrument is to make it segmented and assemble it in orbit. As we move forward, the ability to launch large structures in space that can be reassembled will undoubtedly lead to even more significant discoveries. With 6000 hours allocated for different observation missions, the JWST will enable researchers to work towards solving more of the unanswered questions regarding the cosmos. From deep space observation to exoplanet analysis, the possibilities are endless. Written by Zari Syed Related article: Lonar Lake