Synthesis of new DOPO derivatives and investigation of their synergistic effect with APP-PEI on the flame retardancy of epoxy composite.

Epoxy resin has been extensively used in many industrial and daily applications due to its unique properties. However, the high flammability of epoxy has limited its further development. DOPO derivatives, which are organophosphorus compounds, are highly effective components of flame retardant epoxy composites due to their good compatibility with the resin and their lower toxicity compared to halogenated compounds. This study synthesized sixteen new DOPO derivatives, characterizing their chemical structures with NMR spectroscopy. The combination of synthesized DOPO derivatives and APP-PEI (ammonium polyphosphate-polyethyleneimine) has shown a synergistic effect on enhancing the flame retardancy of epoxy resin with the UL-94 V-0 rating and the LOI value of 28.6%. Moreover, the epoxy composites displayed relatively high mechanical performance with the impact strength of 26-28 kJ m-2.

Dataset of Vietnamese students' academic perfectionism and school alienation.

Across the steadily superseding world, the younger generation is coming under pressure for an increase in the standard and a highly growing demand on their life themselves. This could lead to a variety of problems, including academic perfectionism and school alienation. To gain more insights into these phenomena, we conducted two research projects on students from eight upper secondary schools in Ho Chi Minh City, Vietnam using online surveys, and obtained two datasets. Dataset A covers (i) the level of students' perfectionism; (ii) belief in school meritocracy; (iii) The competitiveness among students; and (iv) the intrinsic motivation to achieve. Dataset B contains students' self-reports about (i) their perceptions of parents' and teachers' academic conditional regard; (ii) academic contingent self-worth; and (iii) school alienation. The numbers of respondents of dataset A and dataset B are 2942 and 2970, respectively.

Evaluating Use Cases for Human Challenge Trials in Accelerating SARS-CoV-2 Vaccine Development.

Human challenge trials (HCTs) have been proposed as a means to accelerate SARS-CoV-2 vaccine development. We identify and discuss 3 potential use cases of HCTs in the current pandemic: evaluating efficacy, converging on correlates of protection, and improving understanding of pathogenesis and the human immune response. We outline the limitations of HCTs and find that HCTs are likely to be most useful for vaccine candidates currently in preclinical stages of development. We conclude that, while currently limited in their application, there are scenarios in which HCTs would be extremely beneficial. Therefore, the option of conducting HCTs to accelerate SARS-CoV-2 vaccine development should be preserved. As HCTs require many months of preparation, we recommend an immediate effort to (1) establish guidelines for HCTs for COVID-19; (2) take the first steps toward HCTs, including preparing challenge virus and making preliminary logistical arrangements; and (3) commit to periodically re-evaluating the utility of HCTs.

Dataset of ex-pat teachers in Southeast Asia's intention to leave due to the COVID-19 pandemic.

The COVID-19 pandemic exerted an adverse influence on the global education system, especially since starting school lockdown. The growth of teacher unemployment figures climbed double-digit and spawned these unexpected sequels. For instance, while native teachers seemed indisposed to leave the profession with the aim of seeking another more profited and seasonal jobs, many ex-pat teachers presented themselves with moving or stayed dilemma in the way the government salvaged their situation. In preference with the ex-pat teacher's case, we elucidated further throughout an e-survey in the International Baccalaureate community on Facebook from 4 to 11 April 2020 for 18,000 ex-pat teachers, who are teaching at Southeast Asia. This dataset includes 307 responses of ex-pat teachers who are staying in Singapore, Thailand, Vietnam, the Philippines, and Indonesia during the pandemic. The dataset comprises (i) Survey partakers' Demographics; (ii) Ex-pat teachers' perceptions in the relation of national, regional and school plans were afoot to the pandemic; (iii) The degree of attachment of ex-pat teacher to their current society, the ex-pat community, friends, and families during the pandemic time; (iv) Ex-pat teachers' embryo intention to reconsider their current teaching location.

Predicting relapse after alcohol use disorder treatment in a high-risk cohort: The roles of anhedonia and smoking.

On average, two-thirds of individuals treated for alcohol use disorder (AUD) relapse within six months. There is a critical need to identify modifiable risk factors associated with relapse that can be addressed during AUD treatment. Candidate factors include mood disorders and cigarette smoking, which frequently co-occur with AUD. We predicted that co-occurrence of mood disorders, cigarette smoking, and other modifiable conditions will predict relapse within six months of AUD treatment. Ninety-five Veterans, 23-91 years old, completed assessments of multiple characteristics including demographic information, co-occurring psychiatric disorders, and medical conditions during residential treatment for AUD. Participants' alcohol consumption was monitored over six months after participation. Logistic regression was used to determine if, mood disorders, cigarette smoking status, alcohol consumption, educational level, and comorbid general medical conditions are associated with relapse after AUD treatment. Sixty-nine percent of Veterans (n = 66) relapsed within six months of study while 31% remained abstinent (n = 29). While education, comorbid general medical conditions, and mood disorder diagnoses were not predictors of relapse, Veterans with greater symptoms of anhedonia, active smokers, and fewer days of abstinence prior to treatment showed significantly greater odds for relapse within six months. Anhedonia and cigarette smoking are modifiable risk factors, and effective treatment of underlying anhedonic symptoms and implementation of smoking cessation concurrent with AUD-focused interventions may decrease risk of relapse.

Medical Conditions Linked to Atherosclerosis Are Associated With Magnified Cortical Thinning in Individuals With Alcohol Use Disorders.

AIMS: Magnetic resonance imaging (MRI) studies report widespread cortical thinning in individuals with alcohol use disorder (AUD), but did not consider potential effects of pro-atherogenic conditions such as hypertension, type 2 diabetes mellitus, hepatitis C seropositivity and hyperlipidemia on cortical thickness. The conditions are associated with regional cortical thinning in those without AUD. We predicted that individuals with concurrent AUD and pro-atherogenic conditions demonstrate the greatest regional cortical thinning in areas most vulnerable to decreased perfusion. METHODS: Treatment-seeking individuals with AUD (n = 126) and healthy controls (CON; n = 49) completed a 1.5 T MRI study. Regional cortical thickness was quantitated via FreeSurfer. Individuals with AUD and pro-atherogenic conditions (Atherogenic+), AUD without pro-atherogenic conditions (Atherogenic-) and CON were compared on regional cortical thickness. RESULTS: Individuals with AUD showed significant bilateral cortical thinning compared to CON, but Atherogenic+ demonstrated the most widespread and greatest magnitude of regional thinning, while Atherogenic- had reduced thickness primarily in anterior frontal and posterior parietal lobes. Atherogenic+ also showed a thinner cortex than Atherogenic- in lateral orbitofrontal and dorso/dorsolateral frontal cortex, mesial and lateral temporal and inferior parietal regions. CONCLUSIONS: Our results demonstrate significant bilateral cortical thinning in individuals with AUD relative to CON, but the distribution and magnitude were influenced by comorbid pro-atherogenic conditions. The magnitude of cortical thinning in Atherogenic+ strongly corresponded to cortical watershed areas susceptible to decreased perfusion, which may result in morphometric abnormalities. The findings indicate that pro-atherogenic conditions may contribute to cortical thinning in those seeking treatment for AUD.

In vivo venous assessment of red blood cell aggregate sizes in diabetic patients with a quantitative cellular ultrasound imaging method: proof of concept.

BACKGROUND: Diabetic patients present higher level of red blood cell (RBC) aggregation contributing to the development of vascular complications. While it has been suggested that this hematology/rheology parameter could bring additional prognostic information for the management of those patients, RBC aggregation screening is not included as a clinical practice. Most medical centers are not equipped to measure properly this parameter, although sedimentation tests can bring some indication. Here, we aimed at evaluating the feasibility of using ultrasound to assess in-vivo hyper-aggregation in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Seventeen diabetic patients and 15 control subjects underwent ultrasound measurements of RBC aggregation in both cephalic and great saphenous veins. Non-invasive in-vivo ultrasound measurements were performed using a newly developed cellular imaging technique, the structure factor size and attenuation estimator (SFSAE). Comparisons with an ex-vivo gold standard rheometry technique were done, along with measurements of pro-aggregating plasma molecule concentrations. RESULTS: In-vivo RBC aggregation was significantly higher in diabetic patients compared with controls for cephalic vein measurements, while a trend (p = 0.055) was noticed in the great saphenous vein. SFSAE measurements were correlated with gold standard in-vitro measures, fibrinogen and C-reactive protein plasma concentrations. CONCLUSION: RBC aggregation can be measured in-vivo in diabetic patients using ultrasound. Prospective studies are needed to determine whether the SFSAE method could help clinicians in the early management of vascular complications in this patient population.

Type IV pilin is glycosylated in Pseudomonas syringae pv. tabaci 6605 and is required for surface motility and virulence.

Type IV pilin (PilA) is a major constituent of pilus and is required for bacterial biofilm formation, surface motility and virulence. It is known that mature PilA is produced by cleavage of the short leader sequence of the pilin precursor, followed by methylation of N-terminal phenylalanine. The molecular mass of the PilA mature protein from the tobacco bacterial pathogen Pseudomonas syringae pv. tabaci 6605 (Pta 6605) has been predicted to be 12 329 Da from its deduced amino acid sequence. Previously, we have detected PilA as an approximately 13-kDa protein by immunoblot analysis with anti-PilA-specific antibody. In addition, we found the putative oligosaccharide-transferase gene tfpO downstream of pilA. These findings suggest that PilA in Pta 6605 is glycosylated. The defective mutant of tfpO (ΔtfpO) shows reductions in pilin molecular mass, surface motility and virulence towards host tobacco plants. Thus, pilin glycan plays important roles in bacterial motility and virulence. The genetic region around pilA was compared among P. syringae pathovars. The tfpO gene exists in some strains of pathovars tabaci, syringae, lachrymans, mori, actinidiae, maculicola and P. savastanoi pv. savastanoi. However, some strains of pathovars tabaci, syringae, glycinea, tomato, aesculi and oryzae do not possess tfpO, and the existence of tfpO is independent of the classification of pathovars/strains in P. syringae. Interestingly, the PilA amino acid sequences in tfpO-possessing strains show higher homology with each other than with tfpO-nonpossessing strains. These results suggest that tfpO and pilA might co-evolve in certain specific bacterial strains.

Genetic analysis of genes involved in synthesis of modified 4-amino-4,6-dideoxyglucose in flagellin of Pseudomonas syringae pv. tabaci.

Glycosylation of flagellin contributes to swimming and swarming motilities, adhesion ability, and consequently virulence in Pseudomonas syringae pv. tabaci 6605. Glycans attached to six serine residues are located in the central region of the flagellin polypeptide. The glycan structure at position Ser 201 was recently revealed to consist of two L-rhamnoses and one modified 4-amino-4,6-dideoxyglucose (viosamine). To clarify the mechanisms for glycosylation of modified viosamine, genes encoding dTDP-viosamine aminotransferase (vioA), dTDP-viosamine acetyltransferase (vioB), and viosamine-derivative transferase (vioT) were isolated and defective mutants were generated. MALDI-TOF-MS analysis of a lysyl endopeptidase-digested peptide including all six glycosylation sites from each flagellin indicated that the molecular masses of the three flagellin mutants were reduced with highly heterogeneous patterns at regular intervals of 146 Da in the mass range from m/z 13,819 to 15,732. The data indicated that the glycopeptides obtained from mutants had glycans consisting only of deoxyhexose instead of the flagellin glycans including the viosamine derivatives determined previously. The motility and virulence on host tobacco leaves were strongly impaired in the Delta vioA mutant and were weakly reduced in the Delta vioB and Delta vioT mutant strains. These results suggest that the genes vioA, vioB, and vioT are essential for glycosylation of flagellin, and accordingly are required for bacterial virulence.

Cyclic changes in blood echogenicity under pulsatile flow are frequency dependent.

Previous in vivo and in vitro studies have demonstrated that blood echogenicity varies under pulsatile flow, but such changes could not always be measured at physiological stroke rates. The apparent contradiction between these studies could be a result of the use of different ultrasound frequencies. Backscattered signals from porcine blood were measured in a pulsatile Couette flow apparatus. Cyclic changes in shear rate for stroke rates of 20 to 70 beats per minute (BPM) were applied to the Couette system, and different blood samples were analyzed (normal blood and blood with hyperaggregating erythrocytes promoted with dextran). To confirm that cyclic echogenicity variations were observable, spectral analysis was performed to verify if changes in echo-amplitude corresponded to the stroke rate applied to the flow. Echogenicity was measured with two single-element transducers at 10 and 35 MHz. At 35 MHz, cyclic variations in backscatter were observed from 20 to 70 BPM. However at 10 MHz, they were detected only at 20 BPM. For all cases except for hyperaggregating red blood cells (RBCs) at 20 BPM, the magnitude of the cyclic variations were higher at 35 MHz. We conclude that cyclic variations in RBC aggregation exist at physiological stroke rates, unlike what has been demonstrated in previous in-vitro studies at frequencies of 10 MHz. The increased sensitivity at 35 MHz to small changes in aggregate size might be the explanation for the better characterization of RBC aggregation at high stroke rates. Our results corroborate in-vivo observations of cyclic blood echogenicity variations in patients using a 30-MHz intravascular ultrasound catheter.