Phthalate puzzle

The most common plasticizer, phthalates, are facing stricter regulations due to their omnipresence and possible effects on human health, and environment. But high cost, lack of application range, and unknown long-term effects of non-phthalate alternatives make the scenario puzzling.     

What is a Species? An endless debate

Everybody is familiar with the ubiquitous term ‘species’. But what is a species? Undeniably, this is one of the most complex dilemmas in the history of biology. There is no other concept in biology as elementary yet controversial as the concept of species. In practice, a species is regarded as the fundamental unit of comparison in all biological disciplines like systematics, evolution, ecology, ethology, physiology, and genetics. However, little agreement exists in the scientific community regarding the nature of species, whether it is a real entity or a cultural artifact, its biological significance or how to delineate a species. This article is a review of the seemingly endless debate on the species concept and its implications.     

Emerging trends in topological insulators and topological superconductors

Topological insulators are new class of materials which are characterized by a bulk band gap like ordinary band insulators but have protected conducting states on their edges or surfaces. These states emerge due to the combination of spin-orbit coupling and time reversal symmetry. Also, these states are insensitive to scattering by non-magnetic impurities. A two-dimensional topological insulator has one dimensional edge states in which the spin-momentum locking of the electrons give rise to quantum spin Hall effect. A threedimensional topological insulator supports novel spin-polarized 2D Dirac fermions on its surface. These topological insulator materials have been theoretically predicted and experimentally observed in a variety of 2D and 3D systems, including HgTe quantum wells, BiSb alloys, and Bi₂Te₃, Bi₂Se₃ crystals. Moreover, proximity induced superconductivity in these systems can lead to a state that supports zero energy Majorana fermions, and the phase is known as topological superconductors. In this article, the basic idea of topological insulators and topological superconductors are presented along with their experimental development.     

Putative Role of Cardio Metabolic Risk Among Poorly Controlled Asthmatics in South Indian Population

Mortality and morbidity attributed to asthma remains to be the biggest nightmare worldwide. Hence, the study was aimed to compare the cardio metabolic risk factors as assessed by Body mass index (BMI), waist hip ratio (WHR), serum triacylglycerol and uric acid in well controlled and poorly controlled asthmatics and to correlate these parameters with the severity of asthma. A case control study was conducted on 90 subjects who were segregated into well controlled asthmatics (n = 30) and poorly controlled asthmatics (n = 30) who were diagnosed based on Global initiative for Asthma management guidelines and healthy volunteers (n = 30). Centrifuged fasting venous blood samples were used for biochemical analysis, pulmonary function test, BMI, and waist hip ratio (WHR) were measured. The statistical analysis was done using SPSS version 17. There was a significant increase in BMI, WHR, lipid profile, serum uric acid and decrease in forced expiratory volume (FEV1), forced vital capacity (FVC), and FEV1/FVC in poorly controlled asthmatics. There was a significant association between FEV1 and serum uric acid, BMI and Triacylgycerol in poorly controlled asthmatics. Poorly controlled asthmatics have greater risk of developing cardiometabolic problems. Serum uric acid can be used as one of the severity markers in asthma to assess cardio metabolic risk.     

The major players in adaptive immunity

How do we remain healthy, for the most parts, in the midst of an environment teeming with opportunistic and infectious microbes, potential carcinogens and allergens? The fact is that our immune system, by and large, does a fine job in protecting us. It is therefore important to understand the organization of the immune network, which is broadly categorized into two groups: innate and adaptive. Cells involved in innate immunity are the first to come into contact with invading microbes, similar to the border security force, and respond rapidly but in a non-specific manner. On the other hand, the cells involved in adaptive immunity are slower to respond but act in a very specific manner. Though the primary response is slow, the secondary response is much faster and demonstrates memory. This article will focus on some important features and key players involved in the adaptive immune response. The first part deals with the humoral immune response mediated mainly by immunoglobulins produced by the B cells. The second part deals with T cells, the Major Histocompatibility Complex (MHC)-encoded molecules, and Recombination Activating Genes (RAG) responsible for generating diverse B-cell receptors (BCR) and T-cell receptors (TCR). With the advent of newer and smarter infectious agents, it is important to understand the working of the immune network as more research in this area may facilitate the development of better protective strategies.     

Local Lyapunov Exponents and characteristics of fixed／periodic points embedded within a chaotic attractor

A chaotic dynamical system is characterized by a positive averaged exponential separation of two neighboring trajectories over a chaotic attractor. Knowledge of the Largest Lyapunov Exponent λ1 of a dynamical system over a bounded attractor is necessary and sufficient for determining whether it is chaotic (λ1＞0) or not (λ1≤0). We intended in this work to elaborate the connection between Local Lyapunov Exponents and the Largest Lyapunov Exponent where an altemative method to calculate λ1has emerged. Finally, we investigated some characteristics of the fixed points and periodic orbits embedded within a chaotic attractor which led to the conclusion of the existence of chaotic attractors that may not embed in any fixed point or periodic orbit within it.     

Correlation between serum lipid profile and carotid intima-media thickness in Polycystic Ovarian Syndrome

Abnormal lipid profile is often found in women with Polycystic Ovary Syndrome. To assess the impact of abnormal lipid profile on atherosclerosis in young Polycystic Ovary Syndrome women, carotid intima-media thickness as judged by B-mode ultrasonography were done in 30 young (18–35 yrs) Polycystic Ovary Syndrome women and in similarly age-matched 30 apparently healthy controls. Compared to controls, young Polycystic Ovary Syndrome women had significantly elevated serum total cholesterol, triglyceride and LDL-C levels and carotid intima-media thickness. HDL-C level did not differ significantly between two groups of women. In Polycystic Ovary Syndrome women carotid intima-media thickness was positively correlated with serum total cholesterol, triglyceride and LDL-C and negatively correlated with serum HDL-C. Our study suggests that even young Polycystic Ovary Syndrome women are prone to atherosclerosis from early age.     

Comparative Study of Serum Amylase and Lipase in Acute Pancreatitis Patients

To establish utility of single enzymatic marker for the diagnosis of acute pancreatitis. This is a cohort study. Tertiary care centre proven cases of acute pancreatitis (n = 50) admitted in surgery ward between December 2011 and May 2013 were included in the study. Serum amylase and lipase were performed along with many analytes. All relevant data including serum lab values and imaging were collected. All 50 patients included in the study had raised serum lipase, 42 patients had both amylase and lipase raised, 8 patients had amylase normal but lipase raised. In smaller hospitals where limited lab and radiological facilities are available, estimation of serum lipase will be a better choice over serum amylase in diagnosis of acute pancreatitis.     

Vanishing species: The planet in crisis

Rapid extinction of species is one of the most serious ecological problems faced by humanity today. Species are disappearing at a pace unprecedented in the history of the planet putting the very future of life at risk. The irony is that the root of the crisis is another species, Homo sapiens rather than some physical events that is poised to threaten its own survival. This article gives a brief introduction to the crisis, its consequences and possible mitigation strategies.