Optimizing Microfluidic Design for Cell Separation

To evaluate the performance of various designs of crossflow filtration microfluidic devices, blood flow was modeled using computational fluid dynamics software (COMSOL Multiphysics). Velocity profiles were generated and used to analyze four critical design parameters: pillar size, pillar shape, gap size, and wall length. These parameters were optimized to yield greatest flow from an unfiltered main channel into two filtered side channels of the device, thereby maximizing filtration capacity. Devices containing pillars of 10 µm diameter yielded a significantly greater filtration capacity than devices with pillars of 20 µm diameter. Flow patterns from the main channel to the side channels were not significantly affected when circular, octagonal, and hexagonal pillars were compared; however, use of triangular and square pillars caused a reduction in side channel flow rates. Side channel velocities consistently improved as gap sizes were increased from 3.0 µm to 8.0 µm; however, 3.5 µm gaps were included in the final design for the purpose of separating red and white blood cells. Backflow prevention walls were placed at bends in the device and were systematically lengthened until all backflow was eliminated. Following optimization of the microfluidic device, two prototypes were prepared: a polydimethylsiloxane (PDMS) device with glass backing and a silicon device with PDMS backing. The filtration capacity of these devices were tested using polystyrene microspheres with sizes corresponding to those of red and white blood cells. In both prototypes, between 73 and 75% of small microspheres were consistently filtered into the side channels. Silicon-PDMS devices demonstrated better retention of large microspheres in the main channel and less microsphere agglomeration than did PDMS-glass devices. The benefits of silicon-PDMS devices, however, came at the cost of a difficult fabrication process

Data compatibility in the addiction sciences: An examination of measure commonality

The need for comprehensive analysis to compare and combine data across multiple studies in order to validate and extend results is widely recognized. This paper aims to assess the extent of data compatibility in the substance abuse and addiction (SAA) sciences through an examination of measure commonality, defined as the use of similar measures, across grants funded by the National Institute on Drug Abuse (NIDA) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Data were extracted from applications of funded, active grants involving human-subjects research in four scientific areas (epidemiology, prevention, services, and treatment) and six frequently assessed scientific domains. A total of 548 distinct measures were cited across 141 randomly sampled applications. Commonality, as assessed by density (range of 0–1) of shared measurement, was examined. Results showed that commonality was low and varied by domain/area. Commonality was most prominent for (1) diagnostic interviews (structured and semi-structured) for substance use disorders and psychopathology (density of 0.88), followed by (2) scales to assess dimensions of substance use problems and disorders (0.70), (3) scales to assess dimensions of affect and psychopathology (0.69), (4) measures of substance use quantity and frequency (0.62), (5) measures of personality traits (0.40), and (6) assessments of cognitive/neurologic ability (0.22). The areas of prevention (density of 0.41) and treatment (0.42) had greater commonality than epidemiology (0.36) and services (0.32). To address the lack of measure commonality, NIDA and its scientific partners recommend and provide common measures for SAA researchers within the PhenX Toolkit

JAK1/2 inhibition with baricitinib in the treatment of autoinflammatory interferonopathies

BACKGROUND. Monogenic IFN-mediated autoinflammatory diseases present in infancy with systemic inflammation, an IFN response gene signature, inflammatory organ damage, and high mortality. We used the JAK inhibitor baricitinib, with IFN-blocking activity in vitro, to ameliorate disease. METHODS. Between October 2011 and February 2017, 10 patients with CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures), 4 patients with SAVI (stimulator of IFN genes-associated [STING-associated] vasculopathy with onset in infancy), and 4 patients with other interferonopathies were enrolled in an expanded access program. The patients underwent dose escalation, and the benefit was assessed by reductions in daily disease symptoms and corticosteroid requirement. Quality of life, organ inflammation, changes in IFN-induced biomarkers, and safety were longitudinally assessed. RESULTS. Eighteen patients were treated for a mean duration of 3.0 years (1.5-4.9 years). The median daily symptom score decreased from 1.3 (interquartile range [IQR], 0.93-1.78) to 0.25 (IQR, 0.1-0.63) (P < 0.0001). In 14 patients receiving corticosteroids at baseline, daily prednisone doses decreased from 0.44 mg/kg/day (IQR, 0.31-1.09) to 0.11 mg/kg/day (IQR, 0.02-0.24) (P < 0.01), and 5 of 10 patients with CANDLE achieved lasting clinical remission. The patients' quality of life and height and bone mineral density Z-scores significantly improved, and their IFN biomarkers decreased. Three patients, two of whom had genetically undefined conditions, discontinued treatment because of lack of efficacy, and one CANDLE patient discontinued treatment because of BK viremia and azotemia. The most common adverse events were upper respiratory infections, gastroenteritis, and BK viruria and viremia. CONCLUSION. Upon baricitinib treatment, clinical manifestations and inflammatory and IFN biomarkers improved in patients with the monogenic interferonopathies CANDLE, SAVI, and other interferonopathies. Monitoring safety and efficacy is important in benefit-risk assessment

Suboptimal SARS-CoV-2-specific CD8+ T cell response associated with the prominent HLA-A*02:01 phenotype

An improved understanding of human T cell-mediated immunity in COVID-19 is important for optimizing therapeutic and vaccine strategies. Experience with influenza shows that infection primes CD8+ T cell memory to peptides presented by common HLA types like HLA-A2, which enhances recovery and diminishes clinical severity upon reinfection. Stimulating peripheral blood mononuclear cells from COVID-19 convalescent patients with overlapping peptides from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to the clonal expansion of SARS-CoV-2−specific CD8+ and CD4+ T cells in vitro, with CD4+ T cells being robust. We identified two HLA-A*02:01-restricted SARS-CoV-2-specfic CD8+ T cell epitopes, A2/S269–277 and A2/Orf1ab3183–3191. Using peptide−HLA tetramer enrichment, direct ex vivo assessment of A2/S269+CD8+ and A2/Orf1ab3183+CD8+ populations indicated that A2/S269+CD8+ T cells were detected at comparable frequencies (∼1.3 × 10−5) in acute and convalescent HLA-A*02:01+ patients. These frequencies were higher than those found in uninfected HLA-A*02:01+ donors (∼2.5 × 10−6), but low when compared to frequencies for influenza-specific (A2/M158) and Epstein–Barr virus (EBV)-specific (A2/BMLF1280) (∼1.38 × 10−4) populations. Phenotyping A2/S269+CD8+ T cells from COVID-19 convalescents ex vivo showed that A2/S269+CD8+ T cells were predominantly negative for CD38, HLA-DR, PD-1, and CD71 activation markers, although the majority of total CD8+ T cells expressed granzymes and/or perforin. Furthermore, the bias toward naïve, stem cell memory and central memory A2/S269+CD8+ T cells rather than effector memory populations suggests that SARS-CoV-2 infection may be compromising CD8+ T cell activation. Priming with appropriate vaccines may thus be beneficial for optimizing CD8+ T cell immunity in COVID-19

CD8+ T cells specific for an immunodominant SARS-CoV-2 nucleocapsid epitope display high naive precursor frequency and TCR promiscuity

To better understand primary and recall T cell responses during coronavirus disease 2019 (COVID-19), it is important to examine unmanipulated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells. By using peptide-human leukocyte antigen (HLA) tetramers for direct ex vivo analysis, we characterized CD8+ T cells specific for SARS-CoV-2 epitopes in COVID-19 patients and unexposed individuals. Unlike CD8+ T cells directed toward subdominant epitopes (B7/N257, A2/S269, and A24/S1,208) CD8+ T cells specific for the immunodominant B7/N105 epitope were detected at high frequencies in pre-pandemic samples and at increased frequencies during acute COVID-19 and convalescence. SARS-CoV-2-specific CD8+ T cells in pre-pandemic samples from children, adults, and elderly individuals predominantly displayed a naive phenotype, indicating a lack of previous cross-reactive exposures. T cell receptor (TCR) analyses revealed diverse TCRαβ repertoires and promiscuous αβ-TCR pairing within B7/N105+CD8+ T cells. Our study demonstrates high naive precursor frequency and TCRαβ diversity within immunodominant B7/N105-specific CD8+ T cells and provides insight into SARS-CoV-2-specific T cell origins and subsequent responses

The effects of the principal's leadership style on teacher motivation : a comparative study of missionary schools in Australia and Lebanon

This thesis examines the effects of principal's leadership style on teacher motivation and identifies the motivational strategies if any being used in six schools belonging to Lebanese missionary orders. Three of the schools in the study are located in Australia and three are in Lebanon. The schools are managed by clergy, most of whom have qualifications in theology but few have any qualifications in education

Pediatric Health Risk Assessment for Exposure to Aluminum from Infant Formulas and Children under the Age of Five’s Food Products among Arab Infants: Experience from Lebanon

Chronic dietary aluminum (Al) exposure can have various negative effects on health. The aim of our study is to (1) assess the contamination level of Al in infant formulas (n = 41) and baby food products (n = 76) available in the Lebanese market, and to (2) evaluate the margin of exposure of Al through the consumption of these foods among children under the age of five in Lebanon. Flame atomic absorption spectrometry (FAAS) was used to evaluate all of the samples. Al levels in all tested children’s food items were below the limit of detection. The highest Al level was detected in cornflakes (0.361 ± 0.049 mg/kg) and pureed foods (0.362 ± 0.079 mg/kg). Among infants aged 0–23 months, the average Al exposure due to the daily intake of infant formulas and baby foods was 0.01 and 0.0104 mg/kg BW/day for males and females, respectively. Babies aged 8–10 and 3–5 months had the highest and lowest levels of Al exposure, respectively. Additionally, the toxicological contribution of Al exposure determined for several age groups to a provisional tolerated weekly intake (PTWI) set by JECFA was  <6% and  <7% for males and females, respectively. The total Al exposure through the consumption of infant formulas and complementary foods among all ages in both males and females was below the values of weekly tolerable intakes (2 mg/kg/BW/W) set by JECFA. However, the values of hazard quotient (HQ) exceeded 1 in both male and female Lebanese infants. As a result, the risk of infants being exposed to Al in baby foods needs to be continuously considered