Depletion zone in two-dimensional deposits of soft microgel particles.

HYPOTHESIS: Microgels are a class of model soft colloids that act like surfactants due to their amphiphilicity and are spontaneously adsorbed to the fluid-air interface. Here, we exploit the surfactant-like characteristics of microgels to generate Marangoni stress-induced fluid flow at the surface of a drop containing soft colloids. This Marangoni flow combined with the well-known capillary flow that arises during the evaporation of a drop placed on a solid surface, leads to the formation of a novel two-dimensional deposit of particles with distinct depletion zones at its edge. EXPERIMENTS: The evaporation experiments using sessile and pendant drops containing microgel particles were carried out, and the microstructure of the final particulate deposits were recorded. The kinetics of the formation of the depletion zone and its width is studied by tracking the time evolution of the microgel particle monolayer adsorbed to the interface using in situ video microscopy. FINDINGS: The experiments reveal that the depletion zone width linearly increases with droplet volume. Interestingly, the depletion zone width is larger for drops evaporated in pendant configuration than the sessile drops, which is corroborated by considering the gravitational forces exerted on the microgel assembly on the fluid-air interface. The fluid flows arising from Marangoni stresses and the effect of gravity provide novel ways to manipulate the self-assembly of two-dimensional layers of soft colloids.

Triple-line dynamics of a soft colloid-laden drop on a hydrophobic surface.

Evaporation of fluid from a pinned drop placed on solid surface proceeds via constant contact radius (CCR) mode, with a continuous reduction in the contact angle. The reduction of contact angle leads to an imbalance of interfacial tensions at the three-phase contact line. When the unbalanced force is sufficiently strong, the drop slips from the pinned contact line and slides inward. Depinning of the drop alters the mode of evaporation to constant contact angle (CCA) mode till it repins onto the surface. The change in evaporation mode from CCR to CCA is usually achieved by tuning the pinning energy barrier by controlling the surface properties of the substrate. Here, we demonstrate that the evaporation mode can be controlled by solely tailoring the surface tension of the drop, which is achieved in microgel particle-laden sessile drops that show spontaneous adsorption of microgels to the air/water interface, leading to a decrease in the interfacial tension. We show that droplets containing a sufficient number of microgels evaporate predominantly in CCR mode even on a hydrophobic surface, and the contact line remains pinned throughout the evaporation of the drop. Interestingly, the contact line dynamics can be controlled by tuning the softness of the microgels and the particle concentration in the drops.

Sero-prevalence of Nipah antibodies among close contacts of the index case during 2019 Ernakulam outbreak.

Introduction: Nipah virus (NiV) infection is a fatal emerging zoonotic disease. Infection with NiV has a wide range of clinical spectrum which can range from asymptomatic cases to acute respiratory distress syndrome (ARDS). The index case of NiV infection of 2019 outbreak in Ernakulam district was a 23-year-old male who presented with features of encephalitis. This study was undertaken to address the subclinical or asymptomatic NiV infection amongst the close contacts of this index case by using NiV-specific Immunoglobulin IgM and IgG antibodies. The index case was first treated in a primary care center. He survived the infection and was discharged after a period of 108 days from the tertiary care facility where he was treated eventually. Methods: Serum samples from 49 close contacts of the index case were collected and tested for anti-NiVIgM and anti-NiVIgG antibodies. The contacts included health care workers including those from the primary care facility, family members, and his friends. Results: Most common type of exposure included physical contact (59.2%), followed by exposure to body fluids (22.4%). Conclusion: None of the 49 contacts tested positive for anti-NiV human IgM and anti-NiVIgG antibodies. There were no subclinical cases amongst the close contacts of Nipah index case during the 2019 Kerala outbreak.

Temporal evolution of viscoelasticity of soft colloid laden air-water interface: a multiple mode microrheology study.

Mechanical properties of particle laden interfaces is crucial for various applications. For water droplets containing soft microgel particles, passive microrheology studies have revealed that the dynamically varying surface area of the evaporating drop results in a viscous to viscoelastic transition along the plane of the interface. However, the behaviour of the medium orthogonal to the interface has been elusive to study using passive microrheology techniques. In this work, we employ optical tweezers and birefringent probe particles to extract the direction-resolved viscoelastic properties of the particle-laden interface. By using special types of birefringent tracer particles, we detect not only the in-plane translational mode but also the out-of-plane translational (perpendicular to the interface) and rotational modes. We first compare different passive methods of probing the viscoelasticity of the microgel laden interface of sessile drop and then study the modes perpendicular to the interface and the out-of-plane rotational mode using optical tweezers based passive microrheology. The viscoelasticity of the interface using two different methods, i.e., multiple-particle tracking passive microrheology using video microscopy and by trapping birefringent tracer particles in optical tweezers, relying on different models are studied and found to exhibit comparable trends. Interestingly, the mode orthogonal to the interface and the rotational mode also show the viscous to viscoelastic transition as the droplet evaporates, but with lesser viscoelasticity during the same evaporation time than the in-plane mode.

Epidemiological and clinical characterization of dengue virus serotypes during 2017-2019 in southern Kerala, India.

BACKGROUND: In the context of the largest dengue outbreak in the state of Kerala, India in 2017, along with global evidence of changing epidemiology of dengue virus and its distribution, this study was planned to understand the epidemiological pattern of dengue infection and contemplate the clinical presentations of different serotypes. METHODS: This cross-sectional study was conducted in the Thiruvananthapuram and Kollam districts of Kerala, India, spanning 3 y from 2017 to 2019. We recruited adult patients based on the World Health Organization case definition of probable dengue fever to study their virological, spatial and clinical characteristics. RESULTS: Dengue infection was identified in 113 (33.9%) of the 333 probable dengue patients recruited. Dengue virus 1 (DENV1), along with its combinations (59.09%), was the predominant serotype during 2017, followed by DENV2. There was a marked increase in the proportion of DENV4 cases (34.56%) and concurrent infections (26%) in 2019. DENV3 infections were more likely to present with warning signs (adjusted relative risk 6.14 [95% confidence interval 1.3 to 29.4]) and a significantly lower platelet count (p=0.02). CONCLUSIONS: The results highlight the hyperendemicity of dengue infection in the state and the changing pattern of dengue virus predominance along with redominance. The rise in DENV4 and concurrent infections put forth the possibility of a more severe future outbreak.

Evaporative self-assembly of soft colloidal monolayers: the role of particle softness.

We investigate the sessile drop evaporation aided self-assembly of microgel particles by varying their softness. Evaporation of sessile drops containing amphiphilic microgel particles at suitable concentrations results in uniform monolayer deposits that span the entire drop area. At lower concentrations, the deposits are in the form of monolayer coffee rings whose width scales with particle concentration. Using softer microgels synthesised with a lower quantity of crosslinker, we show that the monolayer coffee rings do not form at low particle concentrations. The microgels adsorbed at the interface deform, and the extent of deformation depends on the softness of the microgels as well as their concentration at the interface. Upon complete evaporation of the solvent, the microgel-laden interface is transferred to the substrate. The final deposit shows hexagonal particle arrays where the interparticle separation increases with increasing microgel softness and decreases with particle concentration in the drop. Further insight into the role of microgel softness in the microstructure of the particulate deposits is obtained by measuring the viscoelasticity of the particle-laden interface. Interestingly, the interface loaded with lesser crosslinked microgels exhibits viscoelastic nature even at lower particle concentrations, whereas the higher crosslinked microgels show viscous behaviour.

Clinical presentation, diagnosis and management of aerodigestive tract foreign bodies in the adult population: Part 1.

In the adult population, foreign bodies may be accidentally or intentionally ingested or even inserted into a body cavity. The majority of accidentally ingested foreign bodies pass through the alimentary tract without any complications and rarely require intervention. Accidentally ingested foreign bodies are usually fish bones, bones of other animals, and dentures. Oesophageal food impaction is the commonest cause of oesophageal foreign bodies in the Western hemisphere. Intentionally ingested foreign bodies may be organic or inorganic, and often require intervention; these patients have either underlying psychological or mental disease or are involved in illegal activities such as body packing, which involves trafficking narcotics. Imaging plays a crucial role in not only identifying the type, number and location of the foreign body but also in excluding any complications. In this comprehensive pictorial review, we provide an overview of the spectrum of foreign bodies ingested in adults, emphasising the role of various imaging modalities, their limitations and common foreign body mimickers on imaging.

Genetic basis of hypercholesterolemia in adults.

We investigated monogenic and polygenic causes of hypercholesterolemia in a population-based cohort, excluding secondary hypercholesterolemia, and using an established framework to identify pathogenic variants. We studied 1682 individuals (50.2 ± 8.6 years, 41.3% males) from southeast Minnesota with primary hypercholesterolemia (low-density lipoprotein cholesterol (LDL-C) ≥155 mg/dl in the absence of identifiable secondary causes). Familial hypercholesterolemia (FH) phenotype was defined as a Dutch Lipid Clinic Network (DLCN) score ≥6. Participants underwent sequencing of LDLR, APOB, and PCSK9, and genotyping of 12 LDL-C-associated single-nucleotide variants to construct a polygenic score (PGS) for LDL-C. The presence of a pathogenic/likely pathogenic variant was considered monogenic etiology and a PGS ≥90th percentile was considered polygenic etiology. The mean LDL-C level was 187.3 ± 32.3 mg/dl and phenotypic FH was present in 8.4% of the cohort. An identifiable genetic etiology was present in 17.1% individuals (monogenic in 1.5% and polygenic in 15.6%). Phenotypic and genetic FH showed poor overlap. Only 26% of those who met the clinical criteria of FH had an identifiable genetic etiology and of those with an identifiable genetic etiology only 12.9% met clinical criteria for FH. Genetic factors explained 7.4% of the variance in LDL-C. In conclusion, in adults with primary hypercholesterolemia, 17.1% had an identifiable genetic etiology and the overlap between phenotypic and genetic FH was modest.

Evaporative self-assembly of the binary mixture of soft colloids.

We have reported experimental studies on the self-assembly and degree of ordering of a binary mixture of soft colloids in monolayer deposits obtained by controlled evaporation. A sessile drop containing soft colloids is evaporated on a solid surface to achieve a loosely-packed two-dimensional deposit with a hexagonal arrangement. The soft microgel particles possess a hard core with a compliant corona, which plays a crucial role in retaining the crystallinity of the binary particle monolayer. The ordered arrangement of the binary mixture is observed even when the bulk diameter of one type of particle is 25% higher than the other, irrespective of their mixing ratio (1 : 3, 1 : 1, and 3 : 1). The microgel particles of both sizes are found to be homogeneously distributed throughout the deposit, completely suppressing the size-dependent particle segregation. Furthermore, in contrast to the self-assembly of bidisperse hard colloids, wherein the lattice distorts to accommodate particles of disparate sizes, in soft colloids, the particles deform at the interface to preserve the crystalline lattice. Moreover, unlike the gradual order-to-disorder transition observed in the deposits consisting of monodisperse microgel particles, the deposits of a binary mixture of microgels exhibit no noticeable trend. The areal disorder parameter, pair correlation function and the shape factor which quantifies the local ordering of particles in the deposit indicate the absence of a distinct order-to-disorder transition for the binary mixtures.

Is Hyperthyroidism a Possible Etiology of Early Onset Dementia?

Dementia, a disabling syndrome of the elderly characterized by the decline in memory and cognition, is increasing in incidence and affects not only the individual but also their family and close ones. Hyperthyroidism can mimic many other diseases and untreated hyperthyroidism can lead to adverse problems of various systems including the heart, bones, muscles, menstrual cycle, and fertility. In this article, we have tried to evaluate the association between hyperthyroidism and dementia, as well as the impact of hyperthyroidism management in the treatment and prevention of dementia. Studies available in the PubMed database have been used, excluding animal studies and including studies of adults above the age of 50. The analysis of studies reveals that thyroid dysfunction can lead to cognitive impairment. It has not been able to prove that hyperthyroidism can lead to an earlier onset of dementia. But subclinical hyperthyroidism, thyroid-stimulating hormone (TSH) levels below the normal range, and high free thyroxine (T4) levels increase the risk of dementia among the elderly. The possible mechanisms involved in this association have also been discussed. Thus, we concluded that it is essential to detect and manage hyperthyroidism at an earlier stage since hyperthyroidism increases the risk of dementia. The possibility of using antithyroid treatment in euthyroid dementia is yet to be studied extensively.

Influence of Vitamin K on Bone Mineral Density and Osteoporosis.

Vitamin K (VK) has an established biological function in blood coagulation and hemostasis and maintains general health and bone wellbeing. VK supplements have been promoted to treat and prevent many diseases, particularly for decreasing fracture risk in osteoporosis, a chronic condition described by weak bone tissue, and a high fracture risk following minor trauma. It affects older people from different races and ethnicity, mainly postmenopausal women. Many kinds of research emphasize the role of VK in improving bone health and preventing osteoporotic bone fracture, but the findings are mostly inconclusive. In this literature review, PubMed and Google Scholar databases were used as the primary sources to select the relevant studies and review the association between VK and bone health and also, to explore the impact of VK supplementation in osteoporosis management. A majority of studies reported that VK has an essential role in promoting bone health. Although some studies revealed that VK might increase bone mineral density and reduce fracture risk in people with osteoporosis, VK supplements' potential benefits were not sufficiently supported. Thus, more clinical studies are needed to determine the positive effects of VK supplementation in osteoporosis prevention and treatment.

Do Menopause and Aging Affect the Onset and Progression of Rheumatoid Arthritis and Systemic Lupus Erythematosus?

Rheumatoid arthritis and systemic lupus erythematosus (SLE) are autoimmune diseases that are commonly seen in the female population. Rheumatoid arthritis mainly consists of distal symmetrical deforming polyarthritis. SLE patients have immune complexes that damage the organs and systems of the body, and this can present with one or more symptoms including the characteristic malar rash, serositis, lupus nephritis, photosensitivity, and arthritis of large joints. The onset and progression of the diseases are affected by physiological processes that occur in the body such as menopause and aging. The studies used as evidence were found in the PubMed, ScienceDirect, ProQuest, Taylor & Francis Online, Wiley Online Library, Ovid, and Oxford Academic databases. By analyzing these studies, the effects of aging and menopause on rheumatoid arthritis and SLE were revealed. In relation to menopause and aging, it was found that there was a progression of disease in women who had rheumatoid arthritis. However, aging and menopause caused the progression of SLE to decrease in women. An earlier age of onset of menopause was correlated with an increased chance of developing rheumatoid arthritis and SLE. Furthermore, while some studies showed that a later onset of SLE caused an increase in the progression of the disease, other studies showed that a later onset of SLE led to a decrease in the progression of the disease. Due to the prevalence of rheumatoid arthritis and SLE in females, we believe that the effects of menopause, age, and other factors on these two diseases should be examined in future studies.

A Review of the Impact of Bariatric Surgery in Women With Polycystic Ovary Syndrome.

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in reproductive-age women that causes infertility. Obesity and insulin resistance are closely tied to the pathophysiology of PCOS. Current first-line treatments include lifestyle modifications, hormone modulators, and laparoscopic ovarian drilling, but little attention has been given to bariatric surgery as a viable option. A detailed review of the literature regarding the outcomes of obese women with PCOS after bariatric surgery is necessary. All studies were found in the PubMed database, limited to females and humans, and selected due to relevancy and quantitative data. Bariatric surgery promotes significant weight loss within one year, which is associated with amelioration of insulin resistance, hyperandrogenism, menstrual irregularity, and ovulatory dysfunction. Surgery successfully mediates the regression of PCOS and promotes successful pregnancy. Thus, we recommend the consideration of bariatric surgery as part of the main treatment considerations in obese patients with PCOS. However, more focused and comprehensive research with better study designs are still needed in the future to investigate PCOS and bariatric surgery.

Fatal Superimposed Bacterial Sepsis in a Healthy Coronavirus (COVID-19) Patient.

Coronavirus disease 2019 (COVID-19) is a highly infectious disease caused by the newly discovered coronavirus, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). The novel coronavirus first emerged in Wuhan, China, in December 2019 and has led to a global pandemic. The virus mainly spreads through respiratory droplets from an infected person, but environmental contamination can also act as a source of infection, making social distancing an important key in containing the spread of infection. Those with underlying health conditions are more susceptible to complications such as acute respiratory distress syndrome, which can be fatal. However, healthy individuals experience a mild flu-like illness or may be asymptomatic, recuperating from the infection even without any particular intervention. We present a case of a healthy COVID positive individual, with no underlying comorbidities, who rapidly deteriorated overnight on readmission to the hospital after initial discharge and succumbed to this disease due to a superimposed bacterial infection with COVID pneumonia. This case report highlights the importance of educating COVID-19 positive patients about the precautions, as well as signs and symptoms of a superimposed bacterial infection, when their plan of care is in a home setting. It also emphasizes the potential role of checking procalcitonin levels as a part of routine laboratory investigation at initial presentation in all suspected as well as confirmed COVID-19 cases to rule out an on-going bacterial infection that can prove fatal in the course of the disease.

Abdominal Pain, an Atypical Presenting Symptom of Granulomatosis with Polyangiitis.

Granulomatosis with polyangiitis (GPA) formerly known as Wegener's granulomatosis, is an anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). It is an uncommon disease with an estimated prevalence of 3 in 100,000 individuals with an equal distribution in both sexes. It is characterized by necrotizing granulomatous vasculitis that primarily affects the upper and lower respiratory tracts and the kidneys.  Our patient's initial presentation was abdominal pain with no typical pulmonary or renal manifestations. Along the course of her hospitalization, she had multiple episodes of drop in hemoglobin and a steady increase in serum creatinine which was thought to be due to IV contrast nephropathy. With this case, we project the need for a high index of clinical suspicion to make an early diagnosis, especially in patients with atypical symptoms such as abdominal pain, and acknowledge the fact that IV contrast can possibly act as a second hit in underlying GPA, unmasking the active renal symptoms of the disease.

Current status quo on COVID-19 including chest imaging.

With each day the number coronavirus disease 2019 (COVID-19) cases continue to rise rapidly and our imaging knowledge of this disease is expeditiously evolving. The role of chest computed tomography (CT) in the screening or diagnosis of COVID-19 remains the subject of much debate. Despite several months having passed since identifying the disease, and numerous studies related to it, controversy and concern still exists regarding the widespread use of chest CT in the evaluation and management of COVID-19 suspect patients. Several institutes and organizations around the world have released guidelines, recommendations and statements against the use of CT for diagnosing or screening COVID-19 infection and advocating its use only for those cases with a strong clinical suspicion of complication or an alternate diagnosis. However, these guidelines and recommendations are in disagreement with majority of the widely available literature, which strongly favour CT as a pivotal tool in the early diagnosis, management and even follow-up of COVID-19 infection. This article besides comprehensively reviewing the current status quo on COVID-19 disease in general, also writes upon the current consensus statements/recommendations on the use of diagnostic imaging in COVID-19 as well as highlighting the precautions and various disinfection procedures being employed world-wide at the workplace to prevent the spread of infection.

Chronic Sheehan's Syndrome - A Differential to be Considered in Clinical Practice in Women with a History of Postpartum Hemorrhage.

Sheehan's syndrome is hypopituitarism due to pituitary gland necrosis resulting from hemorrhagic shock during pregnancy. It is a rare complication with varied manifestations and a considerable delay in diagnosis. We describe the case of a 36-year-old female with eight years of non-specific symptoms of generalized myalgias and intense fatigue managed symptomatically all these years. Further clinical assessment revealed amenorrhea and agalactia ongoing for several years without a clinical diagnosis. A good history and physical led to the diagnosis during a routine outpatient visit. She had significant improvement noted following the commencement of treatment. Previous case reports describe cases being diagnosed after one or other complications from long-term panhypopituitarism. Through this case, we want to illustrate that undiagnosed Sheehan's syndrome is associated with long-term morbidity, and there should be a high index of suspicion for it to be diagnosed during a routine clinical visit and thus prevent complications before a diagnosis can be made. It is essential to create awareness, especially in developed countries like the United States, where it has received less attention over the last few years.