Ultrasensitive Electrochemical Sensor Based on Polyelectrolyte Composite Film Decorated Glassy Carbon Electrode for Detection of Nitrite in Curing Food at Sub-Micromolar Level.

To ensure food quality and safety, developing cost-effective, rapid and precision analytical techniques for quantitative detection of nitrite is highly desirable. Herein, a novel electrochemical sensor based on the sodium cellulose sulfate/poly (dimethyl diallyl ammonium chloride) (NaCS/PDMDAAC) composite film modified glass carbon electrode (NaCS/PDMDAAC/GCE) was proposed toward the detection of nitrite at sub-micromolar level, aiming to make full use of the inherent properties of individual component (biocompatible, low cost, good electrical conductivity for PDMDAAC; non-toxic, abundant raw materials, good film forming ability for NaCS) and synergistic enhancement effect. The NaCS/PDMDAAC/GCE was fabricated by a simple drop-casting method. Electrochemical behaviors of nitrite at NaCS/PDMDAAC/GCE were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimum conditions, the NaCS/PDMDAAC/GCE exhibits a wide linear response region of 4.0 × 10-8 mol·L-1~1.5 × 10-4 mol·L-1 and a low detection 1imit of 43 nmol·L-1. The NaCS/PDMDAAC shows a synergetic enhancement effect toward the oxidation of nitrite, and the sensing performance is much better than the previous reports. Moreover, the NaCS/PDMDAAC also shows good stability and reproducibility. The NaCS/PDMDAAC/GCE was successfully applied to the determination of nitrite in ham sausage with satisfactory results.

Single-cell mRNA sequencing of giant panda (Ailuropoda melanoleuca) seminoma reveals the cellular and molecular characteristics of tumour cells.

Testicular tumours are zoonoses that can occur in not only human, but other animals, include giant pandas. A middle-aged male giant panda named Fufu was diagnosed with a testicular tumour and underwent surgery to remove the entire left testis. The testis was mainly composed of three substantive parts: normal tissue on the outside, tumour tissue in the middle, and necrosis in the centre. HE stains revealed that the tumour was a seminoma. Single-cell mRNA sequence was applied to characterise cellular states and molecular circuitries of giant panda testicular seminoma. Only germ cell markers expressed in nearly all tumour cells, and the tumour cells appeared to be the same subtype of seminoma cells. We identified four clusters with unique genes expression. They were early apoptosis cells (EAC), inactive cells (IC), active cells subcluster 1 (AC-1) and active cells subcluster 2 (AC-2). We utilised monocle tools and found that IC cells was in the initiation stage, and EAC was one type of terminal stage, suggesting that tumour cells may undergo apoptosis in the future. AC-2 was another type of terminal stage, representing a group of progressive cells. Our study represents the first report to utilise scRNA-seq to characterise the cellular states and molecular circuitries of a giant panda testicular tumour. This investigation proposes CD117 and CD30 as dependable markers for future pathologic diagnosis. Our findings also suggest that CTSV and other genes with unique expression patterns in active and progressive giant panda seminoma cells may act as early prognostic biomarkers.

A study on giant panda recognition based on images of a large proportion of captive pandas.

As a highly endangered species, the giant panda (panda) has attracted significant attention in the past decades. Considerable efforts have been put on panda conservation and reproduction, offering the promising outcome of maintaining the population size of pandas. To evaluate the effectiveness of conservation and management strategies, recognizing individual pandas is critical. However, it remains a challenging task because the existing methods, such as traditional tracking method, discrimination method based on footprint identification, and molecular biology method, are invasive, inaccurate, expensive, or challenging to perform. The advances of imaging technologies have led to the wide applications of digital images and videos in panda conservation and management, which makes it possible for individual panda recognition in a noninvasive manner by using image-based panda face recognition method.In recent years, deep learning has achieved great success in the field of computer vision and pattern recognition. For panda face recognition, a fully automatic deep learning algorithm which consists of a sequence of deep neural networks (DNNs) used for panda face detection, segmentation, alignment, and identity prediction is developed in this study. To develop and evaluate the algorithm, the largest panda image dataset containing 6,441 images from 218 different pandas, which is 39.78% of captive pandas in the world, is established.The algorithm achieved 96.27% accuracy in panda recognition and 100% accuracy in detection.This study shows that panda faces can be used for panda recognition. It enables the use of the cameras installed in their habitat for monitoring their population and behavior. This noninvasive approach is much more cost-effective than the approaches used in the previous panda surveys.

P38 Inhibition Prevents Herpes Simplex Virus Type 1 (HSV-1) Infection in Cultured Corneal Keratocytes.

Purpose: To evaluate keratocyte viability and proinflammatory cytokine secretion induced by HSV-1 infection. Methods: Keratocytes were separated from corneal tissues obtained with the SMILE procedure, and an in vitro system was established to study HSV-1 infection in human keratocytes. Cell viability, HSV-1 genomic DNA copy number, and the expression levels of α-SMA, ALDH1A1, phospho-p38, p38, phospho-IRF3, and IRF3 were evaluated. Antibody array and ELISA kits were used to measure the production of proinflammatory cytokines and chemokines. Results: We found that HSV-1 infection reduced cell viability and activated keratocyte transdifferentiation into corneal fibroblast-like cells. Furthermore, p38 inhibition improved cell viability and IFN-ß production and played an anti-inflammatory role by reducing the production of proinflammatory cytokines and chemokines. Conclusions: Our study reveals an important role played by keratocytes during innate immune responses and identifies p38 inhibition as a potential therapeutic approach to control ocular HSV-1 infection.

Age, is it an obstacle for older surgeons to learn laparoscopic approach for colorectal cancer?

Laparoscopic colorectal resection has been extensively accepted for treatment of colorectal cancer. There are several reports about surgeon's age as a factor to have influence on learning laparoscopic approach, and there is no consensus on this point. This study was designed to evaluate the outcomes of laparoscopic colorectal resection in period of learning curve completed by surgeons with different age in order to make clear whether older surgeons may learn laparoscopic approach with more difficulty than younger. From July 2010 to August 2012, the first twenty patients underwent laparoscopic colorectal resection completed by each surgeon were selected for analysis. A total of 240 patients treated by 5 older surgeons with median age of 51 years (range 47-54 years) and 7 younger surgeons with median age of 37 years (range 34-43 years) were divided into group 1 (n = 100) and group 2 (n = 140). The short-term outcomes of laparoscopic surgery of the two groups were compared. Two groups were matched in age, gender, body mass index, American Society of Anesthesiologists (ASA), etc. The median number of lymph nodes harvested was 18 (range 7-63) in group 1 and 16 (range 3-66) in group 2 (P = 0.003); The median operative time in group 1 was 185 min (range 105-480 min) compared to 235 min (range 120-470 min) in group 2 (P < 0.001), and blood loss were 150 ml (range 50-400 ml) and 200 ml (range 50-800 ml), respectively (P < 0.001); Conversion rate in group 2 was lower than in group 1 (12.0 vs 18.6 %, P = 0.196). The mean time to passing of first flatus was 3 day (range 2-5 day) in group 1 and 4 day (range 2-6 day) in group 2 (P = 0.001). Older surgeons can master the laparoscopic skill more easily and quickly. Age is not an obstacle for older surgeons to learn laparoscopic approach for colorectal cancer.

Self-consistent charging in dielectric films under defocused electron beam irradiation.

We clarify the transient and equilibrium charging characteristics of grounded dielectrics due to low-energy defocused electron beam irradiation by a three-dimensional self-consistent simulation model. The model incorporates the electron scattering, transport and trapping. Results show that some electrons can arrive at the grounded substrate due to the internal field and density gradient, forming the leakage current. The transient charging process tends to equilibrium as the surface potential decreases and the leakage electron current increases. The positive and negative space charges are distributed alternately along the beam incident direction. In the equilibrium state, the surface potential and leakage electron current decrease to stable values with increasing film thickness and the trap density, but with decreasing electron mobility. Moreover, the surface potential of the dielectric thin film exhibits a maximum negative value with variation of the beam energy; for example, under the condition of the film thicknesses 0.5 µm and 2 µm, the maximum negative values of surface potentials are -13 V and -98 V in beam energies 2 keV and 3.5 keV, respectively. However, for the thick film, the surface potential decreases with the increase in beam energy.