pKa as a Predictive Descriptor for Electrochemical Anion Adsorption

The adsorption of anions onto metal surfaces is important in many applications including effective (electro)catalyst design, metal surface modification, and contaminant removal in wastewater treatment. In electrocatalysis, anions can be both reactive intermediates or site-blocking spectators, where their adsorption strength therefore dictates the rate of reaction. In this work, we have measured the adsorption energy of a series of carboxylic acids on a Pt (111) single-crystal electrode surface from aqueous solution. We find that the adsorption strength of the carboxylate anion is linearly correlated with its acid-dissociation constant (pKa) and therefore the heterolytic O-H bond dissociation strength in solution. Using density functional theory modeling, we split the anion adsorption energy into a sum of the adsorption energy and electron affinity of a neutral (carboxyl) radical. Surprisingly, the adsorption energy of the carboxyl radicals are similar and therefore the large difference in electron affinity is what dictates anion adsorption strength; the greater the cost in energy to remove the electron from the anion upon adsorption, the weaker its binding. Therefore, at least within a class of anions with similar structure and surface binding atoms, both electron affinity and acidity are predictive descriptors of adsorption strength.

Epithelial organoid supports resident memory CD8 T cell differentiation

Resident Memory T cells (TRM) play a vital role in regional immune defense in barrier organs. Although laboratory rodents have been extensively used to study fundamental TRM biology, poor isolation efficiency, sampling bias and low cell survival rates have limited our ability to conduct TRM-focused high-throughput assays. Here, we engineered a murine vaginal epithelial organoid (VEO)-CD8 T cell co-culture system that supports CD8 TRM differentiation in vitro. The three-dimensional VEOs established from murine adult stem cells resembled stratified squamous vaginal epithelium and induced gradual differentiation of activated CD8 T cells into epithelial TRM. These in vitro generated TRM were phenotypically and transcriptionally similar to in vivo TRM, and key tissue residency features were reinforced with a second cognate-antigen exposure during co-culture. TRM differentiation was not affected even when VEOs and CD8 T cells were separated by a semipermeable barrier, indicating soluble factors' involvement. Pharmacological and genetic approaches showed that TGF-β signaling played a crucial role in their differentiation. We found that the VEOs in our model remained susceptible to viral infections and the CD8 T cells were amenable to genetic manipulation; both of which will allow detailed interrogation of antiviral CD8 T cell biology in a reductionist setting. In summary, we established a robust model which captures bonafide TRM differentiation that is scalable, open to iterative sampling, and can be subjected to high throughput assays that will rapidly add to our understanding of TRM.

Utility of Median-to-Ulnar Sensory Comparative Nerve Conduction Study to Increase Diagnostic Accuracy in Mild Carpal Tunnel Syndrome

Electro-physiological diagnosis of mild Carpal Tunnel Syndrome (CTS) based on traditional median motor and sensory studies are often inconclusive. Therefore, we wanted to investigate the utility of Median-to-Ulnar Sensory Conduction studies in diagnosis of mild CTS. Data from Nerve conduction study (NCS) of 82 cases with symptoms suggestive of CTS from September 2017 to October 2020 attending electrophysiology department of Mount Adora Hospital, Sylhet, Bangladesh was selected for study. About 54(66.0%) out of 82 symptomatic patients were diagnosed as CTS by the conventional method, and 28(34.0%) patients required further investigation as their test report were found to be inconclusive. combining methods showed 70(85.37%) were found to be positive and 12(14.63%) were negative in comparison study. Thus, it can be concluded that those patients found to be negative in conventional methods; comparison method is an option for diagnostic confirmation.

Differential effects of CMV infection on the viability of cardiac cells

Cytomegalovirus (CMV) is a widely prevalent herpesvirus that reaches seroprevalence rates of up to 95% in several parts of the world. The majority of CMV infections are asymptomatic, albeit they have severe detrimental effects on immunocompromised individuals. Congenital CMV infection is a leading cause of developmental abnormalities in the USA. CMV infection is a significant risk factor for cardiovascular diseases in individuals of all ages. Like other herpesviruses, CMV regulates cell death for its replication and establishes and maintains a latent state in the host. Although CMV-mediated regulation of cell death is reported by several groups, it is unknown how CMV infection affects necroptosis and apoptosis in cardiac cells. Here, we infected primary cardiomyocytes, the contractile cells in the heart, and primary cardiac fibroblasts with wild-type and cell-death suppressor deficient mutant CMVs to determine how CMV regulates necroptosis and apoptosis in cardiac cells. Our results reveal that CMV infection prevents TNF-induced necroptosis in cardiomyocytes; however, the opposite phenotype is observed in cardiac fibroblasts. CMV infection also suppresses inflammation, reactive oxygen species (ROS) generation, and apoptosis in cardiomyocytes. Furthermore, CMV infection improves mitochondrial biogenesis and viability in cardiomyocytes. We conclude that CMV infection differentially affects the viability of cardiac cells.

TGF-β signaling is important for female reproductive tract resident memory CD8 T cell development

Tissue-resident memory T cells (TRM) patrol non-lymphoid barrier tissues and provide rapid protection against reinvading pathogens. While TRM formation in several barrier mucosal tissues including intestine and respiratory tract has been investigated, factors that control TRM establishment in the female reproductive tract (FRT) remain unclear. Here we established a model of local FRT infection, characterized CD8 TRM development and probed the role of cytokine TGF-β in TRM formation. We adopted a mouse model of intravaginal lymphocytic choriomeningitis virus (LCMV) infection that generated robust local CD8 T cell response in both the lower FRT (cervix, vagina) and upper FRT (ovaries and uterine horn). Upon viral clearance, CD8 T cells in the tissue gradually adopted mature TRM phenotype. Parabiosis confirmed most antiviral T cells in the FRT were truly resident. There were marked differences in the phenotypes of TRM in upper and lower FRT with CD103+ epithelial TRM predominating the lower FRT mucosa. Longitudinal analysis revealed TRM in both compartments undergoes attrition. The cytokine TGF-β has been implicated in TRM development in number of barrier and visceral organs. Using TGF-β RII deficient transgenic CD8 T cells, we observed that lack of TGF-β receptor signaling impairs acquisition of CD103 and CD69 expression by FRT TRM. However, TGF-β RII deficient CD8 T cells showed elevated expression of effector molecules granzyme-B and interferon-gamma upon in vivo stimulation. Taken together, our data suggest a key role of TGF-β in the formation and function of virus specific TRM in the FRT. Further investigation will provide mechanistic insight on the nature of TGF-β signaling pathway impacting FRT TRM formation.

Supported by NIH grants (P20GM121298 and P20GM109035) and Searle Scholars Foundation

Cellular interactions in resident memory T cell establishment and function

Tissue resident memory T cells (T_RM) are enriched in non-lymphoid tissues and represent a formidable barrier against invading pathogens and tumors. T_RM are armed with deployment ready effector molecules which combined with their frontline location allows them to be early organizing centers of our immune defense. Despite their autonomous nature, T_RM rely on careful collaboration with other immune and non-immune cells located within the barrier organ to exert their superior protective role. Here, we highlight recent studies focusing on cellular interactions that regulate T_RM establishment and function. A deeper understanding of these processes is instrumental in designing new means to target T_RM for desirable outcomes in infectious diseases, cancers and autoimmunity.

Simulation for a Mems-Based CTRNN Ultra-Low Power Implementation of Human Activity Recognition

This paper presents an energy-efficient classification framework that performs human activity recognition (HAR). Typically, HAR classification tasks require a computational platform that includes a processor and memory along with sensors and their interfaces, all of which consume significant power. The presented framework employs microelectromechanical systems (MEMS) based Continuous Time Recurrent Neural Network (CTRNN) to perform HAR tasks very efficiently. In a real physical implementation, we show that the MEMS-CTRNN nodes can perform computing while consuming power on a nano-watts scale compared to the micro-watts state-of-the-art hardware. We also confirm that this huge power reduction doesn't come at the expense of reduced performance by evaluating its accuracy to classify the highly cited human activity recognition dataset (HAPT). Our simulation results show that the HAR framework that consists of a training module, and a network of MEMS-based CTRNN nodes, provides HAR classification accuracy for the HAPT that is comparable to traditional CTRNN and other Recurrent Neural Network (RNN) implantations. For example, we show that the MEMS-based CTRNN model average accuracy for the worst-case scenario of not using pre-processing techniques, such as quantization, to classify 5 different activities is 77.94% compared to 78.48% using the traditional CTRNN.

The degree of polymerization and sulfation patterns in heparan sulfate are critical determinants of cytomegalovirus entry into host cells

Several enveloped viruses, including herpesviruses attach to host cells by initially interacting with cell surface heparan sulfate (HS) proteoglycans followed by specific coreceptor engagement which culminates in virus-host membrane fusion and virus entry. Interfering with HS-herpesvirus interactions has long been known to result in significant reduction in virus infectivity indicating that HS play important roles in initiating virus entry. In this study, we provide a series of evidence to prove that specific sulfations as well as the degree of polymerization (dp) of HS govern human cytomegalovirus (CMV) binding and infection. First, purified CMV extracellular virions preferentially bind to sulfated longer chain HS on a glycoarray compared to a variety of unsulfated glycosaminoglycans including unsulfated shorter chain HS. Second, the fraction of glycosaminoglycans (GAG) displaying higher dp and sulfation has a larger impact on CMV titers compared to other fractions. Third, cell lines deficient in specific glucosaminyl sulfotransferases produce significantly reduced CMV titers compared to wild-type cells and virus entry is compromised in these mutant cells. Finally, purified glycoprotein B shows strong binding to heparin, and desulfated heparin analogs compete poorly with heparin for gB binding. Taken together, these results highlight the significance of HS chain length and sulfation patterns in CMV attachment and infectivity.

Small intestinal immunopathology and GI-associated antibody formation in hereditary alpha-tryptasemia

BACKGROUND

Hereditary alpha-tryptasemia (HαT) is characterized by elevated basal serum tryptase due to increased copies of the TPSAB1 gene. Individuals with HαT frequently present with multisystem complaints, including anaphylaxis and seemingly functional gastrointestinal (GI) symptoms.

OBJECTIVE

We sought to determine the prevalence of HαT in an irritable bowel syndrome cohort and associated immunologic characteristics that may distinguish patients with HαT from patients without HαT.

METHODS

Tryptase genotyping by droplet digital PCR, flow cytometry, cytometry by time-of-flight, immunohistochemistry, and other molecular biology techniques was used.

RESULTS

HαT prevalence in a large irritable bowel syndrome cohort was 5% (N = 8/158). Immunophenotyping of HαT PBMCs (N ≥ 27) revealed increased total and class-switched memory B cells. In the small bowel, expansion of tissue mast cells with expression of CD203c, HLA-DR, and FcεRI, higher intestinal epithelial cell pyroptosis, and increased class-switched memory B cells were observed. IgG profiles in sera from individuals with HαT (N = 21) significantly differed from those in individuals with quiescent Crohn disease (N = 20) and non-HαT controls (N = 19), with increased antibodies directed against GI-associated proteins identified in individuals with HαT.

CONCLUSIONS

Increased mast cell number and intestinal epithelial cell pyroptosis in the small intestine, and class-switched memory B cells in both the gut and peripheral blood associated with IgG reactive to GI-related proteins, distinguish HαT from functional GI disease. These innate and adaptive immunologic findings identified in association with HαT are suggestive of subclinical intestinal inflammation in symptomatic individuals.

Design, Synthesis, and Preliminary Studies of Spiro-isoxazoline-peroxides against Human Cytomegalovirus and Glioblastoma ∥

The association between glioblastoma (GBM) and human cytomegalovirus (HCMV) infection has been the intensely debated topic over the decades for developing new therapeutic options. In this regard, the peroxides from natural and synthetic sources served as potential antiviral and anticancer agents in the past. Herein, a concise and efficient strategy has been demonstrated to access a novel class of peroxides containing a spiro-isoxazoline to primarily investigate the biological activities. The synthetic compounds were evaluated for in vitro antiviral and antiproliferative activity against HCMV and glioblastoma cell line (GBM6), respectively. While compound 13m showed moderate anti-CMV activity (IC₅₀ = 19 μM), surprisingly, an independent biological assay for compound 13m revealed its antiproliferative activity against the human glioblastoma cell line (GBM6) with an IC₅₀ of 10 μM. Hence, the unification of an isoxazoline and peroxide heterocycles could be a potential direction to initiate the HCMV-GBM drug discovery program.

Efficient Excitation of Micro/Nano Resonators and Their Higher Order Modes

We demonstrate a simple and flexible technique to efficiently activate micro/nano-electromechanical systems (MEMS/NEMS) resonators at their fundamental and higher order vibration modes. The method is based on the utilization of the amplified voltage across an inductor, L, of an LC tank resonant circuit to actuate the MEMS/NEMS resonator. By matching the electrical and mechanical resonances, significant amplitude amplification is reported across the resonators terminals. We show experimentally amplitude amplification up to twelve times, which is demonstrated to efficiently excite several vibration modes of a microplate MEMS resonator and the fundamental mode of a NEMS resonator.

Voltage and Deflection Amplification via Double Resonance Excitation in a Cantilever Microstructure

Cantilever electrostatically-actuated resonators show great promise in sensing and actuating applications. However, the electrostatic actuation suffers from high-voltage actuation requirements and high noise low-amplitude signal-outputs which limit its applications. Here, we introduce a mixed-frequency signal for a cantilever-based resonator that triggers its mechanical and electrical resonances simultaneously, to overcome these limitations. A single linear RLC circuit cannot completely capture the response of the resonator under double resonance excitation. Therefore, we develop a coupled mechanical and electrical mathematical linearized model at different operation frequencies and validate this model experimentally. The double-resonance excitation results in a 21 times amplification of the voltage across the resonator and 31 times amplitude amplification over classical excitation schemes. This intensive experimental study showed a great potential of double resonance excitation providing a high amplitude amplification and maintaining the linearity of the system when the parasitic capacitance is maintained low.

Anion Complexation Studies of 3-Nitrophenyl-Substituted Tripodal Thiourea Receptor: A Naked-Eye Detection of Sulfate via Fluoride Displacement Assay

A thiourea-based tripodal receptor L substituted with 3-nitrophenyl groups has been synthesized, and the binding affinity for a variety of anions has been studied by ¹H NMR titrations and nuclear Overhauser enhancement spectroscopy experiments in dimethyl sulfoxide-d₆. As investigated by ¹H NMR titrations, the receptor binds an anion in a 1:1 binding mode, showing the highest binding and strong selectivity for sulfate anion. A competitive colorimetric assay in the presence of fluoride suggests that the sulfate is capable of displacing the bound fluoride, showing a sharp visible color change. The strong affinity of L for sulfate was further supported by UV-vis titrations and density functional theory (DFT) calculations. Time-dependent DFT calculations indicate that the fluoride complex possesses a different optical absorption spectrum (due to charge transfer between the fluoride and the surrounding ligand) than the sulfate complex, reflecting the observed colorimetric change in these two complexes. The receptor was further tested for its biocompatibility on primary human foreskin fibroblasts and HeLa cells, exhibiting an excellent cell viability up to 100 μM concentration.

Stroke in Bangladeshi patients and risk factor

To evaluate comprehensively the distribution of established risk factors of stroke among Bangladeshi patients. This is an observational study. It involved 8400 stroke patients from different hospitals in Bangladesh over a period of sixteen years. Common established risk factors of stroke e.g. age, sex, family history, hypertension, diabetes, ischemic heart disease, smoking, obesity, dyslipidaemia, alcoholism, use of oral contraceptive pill, lack of fresh fruit consumption etc. were evaluated in these patients through a preformed questionnaire and data were analyzed. Majority of the stroke events occurred after the age of forty (82.3%) and the ischemic stroke (72%) is the most common. Apart from non modifiable risk factors (advancing age, sex, Family history of stroke) hypertension was the most common modifiable risk factor found in stroke patients (57.6%) followed by smoking (44.6%), tobacco use (24.3%), OCP use in female (40% of female stroke), diabetes (23%), ischemic heart disease (17.1%), obesity (10.6%) and dyslipidaemia (5.3%). Lack of fresh fruit consumption and alcoholism were found in some of the patients. Stroke is common after the age of forty. Ischemic events are commonest type of stroke. Hypertension, smoking, tobacco use, diabetes and ischemic heart disease were five most common risk factors of stroke. Outlining the common stroke risk factors in our settings, may help the physicians and care givers in managing this disabling disease properly.

Precipitating factor of seizure in epilepsy: experience in a tertiary care hospital

Patients with epilepsy experience recurrent, unprovoked seizures. In most of the cases seizure occurs spontaneously, but there may be association with various triggers. These triggers may act as seizure precipitating factors (SPFs). This study was done to find out the most common SPFs and their relationship to different types epileptic patients attending a tertiary care hospital in Bangladesh. This cross sectional study was carried out in specialized epilepsy weekly outdoor clinic and Medicine outpatient department (OPD) of Dhaka Medical College Hospital from January 2008 to July 2011, which included 1168 epilepsy patients. All patients attending the clinic were included in the study. Epilepsy syndromes were broadly classified into four categories using the classification system of international league against epilepsy (ILAE) namely, generalized epilepsy (GE), localization related epilepsy (LRE), symptomatic and unclassified. Each patient was evaluated and classified by consultant neurologist. All participants were interviewed through a predesigned close ended questionnaire that included a long list of 30 precipitating factors. Among all the patients 71.5% were male, with most common age group 11-20 years (36.8%). About 62% could indentify at least one precipitator. Excitation (25.2%) was the most common SPF reported by patients followed by emotional stress in 17.7%. Fever precipitated seizure in 16.4% of the subjects. A good number of them (15.5%) noticed that whenever there was sleep deprivation, they had an attack of epilepsy. However, drug withdrawal, playing outside and head trauma were also common among the patients, about 11.7%, 11.3% and 8.4% respectively. Most of the patients can identify their seizure precipitant and clustering of many SPFs suggests a common patho-physiologic mechanism for these triggers. Excitation, sleep deprivation, fever, watching television and head trauma showed a strong association with generalized epilepsy. Patients with seizure disorder should be evaluated for presence of SPFs, because identification of these might help in proper management of epilepsy.

Endovascular management of a young patient of stroke with absent right upper limb pulse

A 39 years old, right handed, hypertensive non-diabetic smoker presented with ischemic stroke with left sided hemiplegia and absent right upper limb peripheral pulses. Possible causes of young stroke were searched. Cerebral digital subtraction angiography (DSA) revealed 95% stenosis at origin of brachiocephalic trunk with absent flow in right sub-clavian artery and 75% stenosis at osteum of left vertebral artery with flow reversal through right vertebral artery. Subsequently, stents were placed within the stenosed portion Right brachiocephalic trunk and left vertebral artery. The intervention resulted in immediate restoration of right upper limb pulses and cessation of flow reversal in vertebral artery.