Virtual assessment,training, and evaluation of clinical laboratory technologists amidst peak Covid-19 pandemic: An observational study

Medical technologists are considered a neglected group when it comes to academic interventions. We developed and implemented an educational intervention and assessment for the technologists based on an online questionnaire as a pre-test consisting of questions related to knowledge (n=5), attitude (n=3), and practices (n=4) of daily internal quality control (QC) monitoring via Google Docs survey tool. This study served multiple purposes. It allowed keeping the technologists engaged during the peak of the COVID-19 pandemic while also improving the knowledge, attitude, and practices about the internal quality control using Bio-Rad Unity Real Time (URT) QC software. Subjects were graded based on the scores they received out of 100 (0-60 = poor; 61-79 = good; 80-100 = excellent). Training materials, i.e., a set of 5 videos every week via e-mail, were circulated. A voice-over PowerPoint presentation was also shared for easy comprehension. This activity was repeated after one month. A post-test was administered to assess the improvement. The study results show significant improvement in the technologists'' performance after the intervention.     

我国螨类研究的最新进展

螨类是一种对人类危害极其严重的小型节肢动物,不论从人的健康方面还是农牧林生产方面来说都需要防治及至根除。主要钛螨类的形态特征、生活史、生态类群、对人类的危害及其防治等5个方面简述了我国螨类研究的最新研究进展概况。     

Citric acid improves growth performance and phosphorus digestibility in Beluga (Huso huso) fed diets where soybean meal partly replaced fish meal

A 2 × 3 factorial experiment was conducted to evaluate the effect of partial substitution of dietary fish meal with soybean meal and citric acid (CA) supplementation on growth, food utilization, muscle composition and nutrient digestibility of Beluga, Huso huso. Three isonitrogenic and isoenergetic diets, as SBM₁ (soybean meal protein (SBP):fishmeal protein (FP) = 1:3), SBM₂ (SBP:FP = 2:3) and SBM₃ (SBP:FP = 1:1) containing two levels of CA (0 and 30 g kg⁻¹) were fed to triplicate groups of fish for 8 weeks. The results revealed that adding CA increased (P<0.05) the weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) and decreased (P<0.05) food conversion rate (FCR) whereas partial substitution of fishmeal with soybean meal decreased (P<0.05) growth performance. Partial replacement of fishmeal with SBM (P=0.021) as well as CA supplementation (P=0.019) and their interaction (P<0.001) affected hepatosomatic index (HSI). No differences (P>0.05) were observed for viscerosomatic index (VSI) among treatments (P>0.05). No differences (P>0.05) were detected in moisture, protein of muscle sample among treatments, but lipid content was reduced (P<0.05) while ash content increased (P=0.035) by CA. Soybean meal decreased (P<0.05) nutrient digestibility, whereas CA improved apparent protein and phosphorus (P) digestibility (P=0.011 and P<0.001 respectively). No interaction (P<0.05) between levels of SBM and CA was found on these parameters. Results of the present study indicate that Beluga has a limited ability to utilize SBM as a protein source in practical diets whereas CA can improve growth and nutrient utilization in Beluga.     

DNA algorithm for an unbounded fan-in Boolean circuit

In this paper, we present a new DNA-based evaluation algorithm for a Boolean circuit that employs standard bio-molecular techniques. The algorithm operates on an unbounded fan-in Boolean circuit consisting of AND and OR gates. The whole simulation of our algorithm is proposed in a single test tube in O(1) time complexity and is much easier to implement in the laboratory than previously described models. Furthermore, the algorithm allows for evaluating any number of Boolean circuits in parallel in a single test tube.     

Contribution of a time-dependent and hyperpolarization-activated chloride conductance to currents of resting and hypotonically shocked rat hepatocytes

Hepatocellular Cl- flux is integral to maintaining cell volume and electroneutrality in the face of the many transport and metabolic activities that describe the multifaceted functions of these cells. Although a significant volume-regulated Cl- current (VRAC) has been well described in hepatocytes, the Cl- channels underlying the large resting anion conductance have not been identified. We used a combination of electrophysiological and molecular approaches to describe potential candidates for this conductance. Anion currents in rat hepatocytes and WIF-B and HEK293T cells were measured under patch electrode-voltage clamp. With K+-free salts of Cl- comprising the major ions externally and internally, hyperpolarizing steps between -40 and -140 mV activated a time-dependent inward current in hepatocytes. Steady-state activation was half-maximal at -63 mV and 28-38% of maximum at -30 to -45 mV, previously reported hepatocellular resting potentials. Gating was dependent on cytosolic Cl-, shifting close to 58 mV/10-fold change in Cl- concentration. Time-dependent inward Cl- currents and a ClC-2-specific RT-PCR product were also observed in WIF-B cells but not HEK293T cells. All cell types exhibited typical VRAC in response to dialysis with hypertonic solutions. DIDS (0.1 mM) inhibited the hepatocellular VRAC but not the inward time-dependent current. Antibodies against the COOH terminus of ClC-2 reacted with a protein between 90 and 100 kDa in liver plasma membranes. The results demonstrate that rat hepatocytes express a time-dependent inward Cl- channel that could provide a significant depolarizing influence in the hepatocyte.     

Yellow pigments used in rapid identification of aflatoxin-producing Aspergillus strains are anthraquinones associated with the aflatoxin biosynthetic pathway

Studies on biological control of aflatoxin production in crops by pre-infection with non-toxigenic Aspergillus flavus strains have created a need for improved methods to screen isolates for aflatoxigenicity. We have evaluated two empirical aflatoxigenicity tests: (i) yellow pigment production, and (ii) the appearance of a plum-red color in colonies exposed to ammonium hydroxide vapor. Yellow pigments from aflatoxigenic A. flavus were shown to function as pH indicator dyes. Seven pigments representing most of the pigmentation in extracts have been isolated using color changes when chromatography spots were exposed to ammonium hydroxide vapor to guide fractionation. Their structures have been shown to be norsolorinic acid, averantin, averufin, versicolorin C, versicolorin A, versicolorin A hemiacetal and nidurufin, all of which are known anthraquinone pigments on, or associated with, the aflatoxin biosynthetic pathway in Aspergillus spp. Thus, the basis of both empirical tests for aflatoxigenicity is detecting production of excess aflatoxin biosynthetic intermediates.     

Hyperglycemia-induced activation of human T-lymphocytes with de novo emergence of insulin receptors and generation of reactive oxygen species

Upon activation by phytohemagglutine (PHA), T-lymphocytes (T-cells) express receptors for growth factors, insulin, IGF-1 and IL2 and become insulin sensitive. Diabetic ketoacidosis (DKA) is associated with in vivo emergence of these growth factor receptors without incubation with PHA. As DKA consists of multiple metabolic alterations, in addition to hyperglycemia, we investigated the in vitro effect of different concentrations of glucose (5, 15, and 30 mM) in isolated CD4 of human T-cells at various time intervals (0, 24, 48, and 72 h). Hyperglycemia, but not euglycemia, resulted in de novo emergence of growth factor receptors in a dose- and time-dependent fashion. The activation was also associated with incremental changes in GLUT 4, IRS-1, proinflammatory cytokines, and oxidative stress components. We propose that activation of T-cells with development of insulin receptors in hyperglycemic conditions may serve as a mechanism for control of glucose entry into these cells, thus, protecting them against glucose toxicity.     

Synthesis of some new 1,3/ or 1,4-bis(glucopyranosyl-1,2,4-triazol-5-ylthio)propanes/ or butanes as potential antimicrobial agents

Glucosidation of the appropriate 1,3 or 1,4-bis(4-amino or arylideneamino-2,4-dihydro-3-thioxo-3H-1,2,4-triazol-5-ylthio)propanes or butanes with 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide followed by chromatographic separation gave the corresponding N-, S-, and N,S-bis(glucosides). Chemical transformation leading to new functionalities has been achieved. Antimicrobial screening of 10 selected compounds resulted in their activity against Aspergillus fumigatus, Penicillium italicum, Syncephalastrum racemosum, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli.