Photo-enhanced gas sensing of SnS2 with nanoscale defects.

Recently a SnS2 based NO2 gas sensor with a 30 ppb detection limit was demonstrated but this required high operation temperatures. Concurrently, SnS2 grown by chemical vapor deposition is known to naturally contain nanoscale defects, which could be exploited. Here, we significantly enhance the performance of a NO2 gas sensor based on SnS2 with nanoscale defects by photon illumination, and a detection limit of 2.5 ppb is achieved at room temperature. Using a classical Langmuir model and density functional theory simulations, we show S vacancies work as additional adsorption sites with fast adsorption times, higher adsorption energies, and an order of magnitude higher resistance change compared with pristine SnS2. More interestingly, when electron-hole pairs are excited by photon illumination, the average adsorption time first increases and then decreases with NO2 concentration, while the average desorption time always decreases with NO2 concentration. Our results give a deep understanding of photo-enhanced gas sensing of SnS2 with nanoscale defects, and thus open an interesting window for the design of high performance gas sensing devices based on 2D materials.

[Value of Pediatric Early Warning Score in identifying the condition of critically ill children].

OBJECTIVE: To study the value of Pediatric Early Warning Score (PEWS) in identifying the condition of critically ill children. METHODS: A total of 120 children who were transferred to the pediatric intensive care unit (PICU) from the general ward during hospitalization or admitted to the PICU after emergency treatment in the Xiangya Hospital of Central South University from January to December, 2016 were enrolled as the PICU group. The other 120 children who were admitted to the general ward in the hospital were used as the control group. According to the disease type, the PICU group was further divided into two subgroups: respiratory/circulatory system diseases (n=55) and nervous/other system diseases (n=65). The PEWS score on admission was recorded, and the receiver operating characteristic (ROC) curve was used to analyze the value of PEWS in evaluating patients' condition. RESULTS: The PICU group had a significantly higher PEWS score than the control group (P<0.05). The respiratory/circulatory system disease subgroup had a significantly higher PEWS score than the nervous/other system disease subgroup (P<0.05). In predicting whether the child was admitted to the PICU, PEWS had a sensitivity of 85%, a specificity of 95%, and an area under the ROC curve (AUC) of 0.951 (95% confidence interval: 0.923-0.980) at the optimal cut-off value of 3.5 (PEWS score). The AUC of PEWS was 0.768 in the nervous/other system disease subgroup and 0.968 in the respiratory/circulatory system disease subgroup. The mortality rate of children with a PEWS score of >6, 4-6 and ≤3 was 40%, 21% and 0 respectively (P<0.001). CONCLUSIONS: PEWS can well identify disease severity in critically ill children, and it has different sensitivities in children with different varieties of diseases. PEWS has a good value in predicting children's prognosis.

Oral edible plant vaccine containing hypoallergen of American cockroach major allergen Per a 2 prevents roach-allergic asthma in a murine model.

BACKGROUND: American cockroaches (Periplaneta americana) are an important indoor allergen source and a major risk factor for exacerbations and poor control of asthma. We previously reported that allergen components from American cockroaches exhibit varying levels of pathogenicity. Sensitization to major American cockroach allergen, Per a 2, correlated with more severe clinical phenotypes among patients with allergic airway diseases. MATERIALS AND METHODS: In this study, we examined whether oral plant vaccine-encoding full-length Per a 2 clone-996 or its hypoallergenic clone-372 could exert a prophylactic role in Per a 2-sensitized mice. The cDNAs coding Per a 2-996 and Per a 2-372 were inserted into TuMV vector and expressed in Chinese cabbage. Adult female BALB/c mice were fed with the cabbage extracts for 21 days and subsequently underwent two-step sensitization with recombinant Per a 2. RESULTS: Per a 2-specific IgE measured by in-house ELISA in the sera of Per a 2-372-treated groups were significantly lower than in the control groups after allergen challenge but not the Per a 2-996-treated group. Moreover, Per a 2-372 vaccine markedly decreased airway hyper-responsiveness and infiltration of inflammatory cells into the lungs, as well as reduced mRNA expression of IL-4 and IL-13 in comparison with the control mice. CONCLUSION: Our data suggest that oral administration of edible plant vaccine encoding Per a 2 hypo-allergen may be used as a prophylactic strategy against the development of cockroach allergy.

Identification of the Functional Autophagy-Regulatory Domain in HCLS1-Associated Protein X-1 That Resists Against Oxidative Stress.

HCLS1 Associated Protein X-1 (HAX1) promotes cell survival through attenuation of the damaged signals from endoplasmic reticulum and mitochondria, which are known as prominent intracellular compartments for the autophagic process under stress conditions. This study investigates whether autophagy can be upregulated in response to HAX1 overexpression and identifies the functional motif in HAX1 responsible for the autophagic induction. Autophagosome accumulation, mitochondrial membrane potential (Δψm), and apoptosis were assessed in HEK293 cells post transduction with full-length or truncated HAX1-encoding genes, while empty vector-transduced cells served as control. Upon the oxidative stress, the enhanced autophagy induction was observed in cells overexpressing HAX1, as well as HAX1 truncations that encode peptide segments ranging from amino acids 127-180 (AA127-180). This protective response was further supported by flow cytometry and Western Blot results, in which oxidative stress-induced Δψm dissipation and the programmed cell death were suppressed in HAX1-overexpressing cells, associated with reduced DNA fragmentation and decreased Caspase-9 cleavage. Interestingly, the HAX1-induced autophagy response was abrogated when AA127-180 was removed, compromising the antiapoptotic effects upon oxidative stress. Overall, these data indicate that autophagy induction is involved in HAX1-induced cell protective mechanism, and AA127-180 serves as the functional autophagy-regulatory domain of this antiapoptotic protein.

Paracrine effect of CXCR4-overexpressing mesenchymal stem cells on ischemic heart injury.

It has been reported that CXCR4-overexpressing mesenchymal stem cells (MSCCX4 ) can repair heart tissue post myocardial infarction. This study aims to investigate the MSCCX4-derived paracrine cardio-protective signaling in the presence of myocardial infarction. Mesenchymal stem cells (MSCs) were divided into 3 groups: MSC only, MSCCX4 , and CXCR4 gene-specific siRNA-transduced MSC. Mesenchymal stem cells were exposed to hypoxia, and then MSCs-conditioned culture medium was incubated with neonatal and adult cardiomyocytes, respectively. Cell proliferation-regulating genes were assessed by real-time polymerase chain reaction (RT-PCR). In vitro: The number of cardiomyocytes undergoing DNA synthesis, cytokinesis, and mitosis was increased to a greater extent in MSCCX4 medium-treated group than control group, while this proproliferative effect was reduced in CXCR4 gene-specific siRNA-transduced MSC-treated cells. Accordingly, the maximal enhancement of vascular endothelial growth factor, cyclin 2, and transforming growth factor-ß2 was observed in hypoxia-exposed MSCCX4 . In vivo: MSCs were labeled with enhanced green fluorescent protein (EGFP) and engrafted into injured myocardium in rats. The number of EGFP and CD31 positive cells in the MSCCX4 group was significantly increased than other 2 groups, associated with the reduced left ventricular (LV) fibrosis, the increased LV free wall thickness, the enhanced angiogenesis, and the improved contractile function. CXCR4 overexpression can mobilize MSCs into ischemic area, whereby these cells can promoted angiogenesis and alleviate LV remodeling via paracrine signaling mechanism.

Efficiency and therapeutic effect of modified pigtail probe in anastomosing lacerated lacrimal canaliculus.

OBJECTIVE: To investigate the necessity of modification to the traditional pigtail probe and evaluate its efficiency and therapeutic effect in searching the nasal cut ends and anastomosing the lacerated lacrimal canaliculus. METHODS: Eighty-seven patients (including 87 eyes) suffering from canalicular laceration were randomized into two groups: 41 patients treated with traditional pigtail probes (Group A) and 46 with modified pigtail probes (Group B). During the reconstruction of the lacerated canaliculi, the traditional pigtail probe and the modified pigtail probe were used respectively to seek for the nasal cut ends of lacerated lacrimal canaliculi. Peripherally inserted central catheter (PICCTM) silicone tube with diameter of 0.95 mm was intubated as a stent for 4-6 months. The surgical outcomes were retrospectively analyzed after stent removal. RESULTS: In Group B, the primary success rate of searching the nasal cut ends of lacerated lacrimal canaliculi was 93.48% (43/46) and the final success rate was 97.83% (45/46). No false passage formed in Group B. Statistical significance was found between Group A and Group B as the primary success rates of searching the nasal cut ends (X(2) equal to 10.522, P less than 0.01) and the false passage forming rates were concerned (X(2)) equal to 4.704, P less than 0.05), whereas no significance was found between the two groups as the final success rates were concerned (X(2) equal to 0.007, P larger than 0.05). The mean time of searching the nasal cut ends of lacerated lacrimal canaliculi in Group B was (5.02+/-0.73) minutes and the mean time of operation was (33.90+/-4.84) minutes, and both were significantly shorter than those of Group A (t(1) equal to 9.779, t(2) equal to 10.700, P less than 0.01). The cure rate of Group B was 95.65%, though higher than that of Group A, no statistical significance was found (Z equal to -0.007, P larger than 0.05). Totally, 2 patients (2.30%) were found to be absent of common canaliculus and underwent bicanalicular nasal intubation in the two groups. CONCLUSIONS: Pigtail probes are efficient and convenient apparatus for searching the nasal cut ends of the lacerated lacrimal canaliculi in the reconstruction of canalicular laceration. Necessary or proper modifications to the pigtail probes can minimize the risk of iatrogenic damages or complications and enhance the efficiency and therapeutic effect of canalicular repair.