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Background Streptococcus pneumoniae (S. pneumoniae) is a major cause of bacterial meningitis, septicemia and pneumonia in children. Inappropriate choice of antibiotic can have important adverse consequences for both the individual and the community. Here, we focused on penicillin/cefotaxime non-susceptibility of S. pneumoniae and evaluated appropriateness of targeted antibiotic therapy for children with IPD (invasive pneumococcal diseases) in China. Methods A multicenter retrospective study was conducted in 14 hospitals from 13 provinces in China. Antibiotics prescription, clinical features and resistance patterns of IPD cases from January 2012 to December 2017 were collected. Appropriateness of targeted antibiotics therapy was assessed. Results 806 IPD cases were collected. The non-susceptibility rates of S. pneumoniae to penicillin and cefotaxime were 40.9% and 20.7% respectively in 492 non-meningitis cases, whereas those were 73.2% and 43.0% respectively in 314 meningitis cases. Carbapenems were used in 21.3% of non-meningitis cases and 42.0% of meningitis cases for targeted therapy. For 390 non-meningitis cases with isolates susceptible to cefotaxime, vancomycin and linezolid were used in 17.9% and 8.7% of cases respectively for targeted therapy. For 179 meningitis cases with isolates susceptible to cefotaxime, vancomycin and linezolid were prescribed in 55.3% and 15.6% of cases respectively. Overall, inappropriate targeted therapies were identified in 361 (44.8%) of 806 IPD cases, including 232 (28.8%) cases with inappropriate use of carbapenems, 169 (21.0%) cases with inappropriate use of vancomycin and 62 (7.7%) cases with inappropriate use of linezolid. Conclusions Antibiotic regimens for IPD definite therapy were often excessive with extensive prescription of carbapenems, vancomycin or linezolid in China. Antimicrobial stewardship programs should be implemented to improve antimicrobial use.

Using silicon nanoporous pillar array (Si-NPA) as substrate, a kind of GaN/Si nanoheterostructure (GaN/Si-NPA) is prepared by depositing GaN nanocrystallites on Si-NPA with chemical vapor deposition method. The morphology characteristics and optical properties of GaN/Si-NPA are investigated systematically. Based on GaN/Si-NPA, a self-powered ultraviolet (UV) photodetector (PD) with device structure of ITO/GaN/Si-NPA/sc-Si/Ag is constructed by depositing ITO on GaN layer and silver on single crystal silicon, respectively. At zero bias voltage without an external power supply, GaN/Si-NPA exhibits a responsivity of 0.072 mA/W, a high current on/off ratio of ∼104 (16 μW/cm2) and fast response speeds of 39.98/40.10 ms under an UV light irradiation at 305 nm. The high performance of GaN/Si-NPA is attributed to the built-in electric field in the heterojunction, which is interpreted via building the energy-band diagrams. The results illustrate that GaN/Si-NPA might be a suitable material system for self-powered UV PDs.

In this paper, we report that a silicon hierarchical structure, silicon nanoporous pillar array (Si-NPA), was prepared and its visible photocatalytic properties were studied by selecting methyl orange (MO) as the target substance. It was shown that a broadband visible light absorption beyond 96% was reached and a one-hour degradation of 97.7% was achieved under optimized conditions. The excellent photocatalytic property of Si-NPA was attributed to the enlarged bandgap brought by quantum confinement effect and the unique surface morphology and microstructure of Si-NPA. Our experiments might have put forward a promising route for fabricating Si-based photocatalyst to degrade organic pollutants in water.

The accurate detection of ultraviolet light (UV) has been playing important roles in a variety of fields such as industrial and agricultural production, environmental monitoring and protection, defense and aerospace industries. Semiconductor materials have been widely used in fabricating various photodectors. As a representative of the first generation semiconductor materials, silicon has been applied to fabricate UV photodetector for a long time. For example, the first solid UV detectors were based on UV-enhanced silicon photodiode. Nevertheless, silicon-based photodiodes usually exhibit responses to visible light, which will cause serious disturbances for the detection of UV. Furthermore, crystal silicon is an indirect bandgap semiconductor, which decides that its conversion efficiency and therefore responsivity during the optoelectronic process would be low. All these shortcomings make the effort on developing novel UV photodetectors being both important and necessary. In the past years, great progresses have been achieved in preparing high-quality compound semiconductors with direct and wide bandgaps, and this provides a good opportunity for developing high-performance UV photodectors. As a III-V compound semiconductor with a direct and wide bandgap (~3.4 eV), gallium nitride (GaN) possesses the properties of high electronic mobility and heat conductivity, good chemical and thermal stability, and excellent anti-irradiation capability, and therefore is thought to be one of the most suitable materials for preparing UV detectors. Currently, high-quality GaN thin films are usually prepared by heteroepitaxy technology utilizing sapphire wafers as substrates. However, sapphire is an insulator, which can be used only as a mechanical support instead of a functional substrate and might bring additional technical difficulty in device integration. Such a problem might be solved by using silicon substrate, provided that the large lattice and thermal mismatch between silicon and GaN can be conquered, or it will cause serious problems relating to the device performance and operation stability. A proved method is through introducing nanostructured silicon substrates to construct GaN/Si heterojunction, by which the mismatches could be greatly diminished through a three-dimensional stress release mode at the GaN and silicon interface. Silicon nanoporous pillar array (Si-NPA) is a silicon hierarchical structure characterized by a regular array of well separated, micron-sized and highly nanoporous silicon pillars, and it has been proved an ideal template for preparing silicon-based heterstructures with high-quality interfaces. Here we will report that utilizing Si-NPA as substrates, GaN/Si-NPA nanoheterojunctions were prepared by growing GaN nanocrystallites using a chemical vapor deposition method. Through changing the deposition time, the surface morphology, chemical constitution, and electrical and photoluminescent properties of GaN/Si-NPA can be tuned effectively, and this provided a solid foundation for optimizing the device performance of the subsequently developed UV photodetectors. Through preparing ITO top transparent electrodes and silver back electrodes on these nanoheterojunctions, prototype UV photodectors with a device structure of ITO/GaN/Si-NPA/ sc -Si/Ag were prepared and the photodetection properties were studied. It was shown that high-quality UV detection can be realized without applying any bias, with the response and recovery time being ~0.12 s and ~0.24 s, respectively. For the monochromatic UV light with a wavelength of 340 nm, a responsivity of ~0.15 mA/W was achieved. These results might have provided a novel route for developing Si-based GaN UV photodetectors.

Background Fungal infections after liver transplantation have received considerable interests because of their association with substantial morbidity and mortality. This study investigated risk factors of fungal infection after liver transplantation. Material/methods Retrospective analysis was performed based on clinical data from 120 patients with fungal infection after liver transplantation from January 1, 2003 to May 30, 2012. χ2 test was used to analyze risk factors for fungal infections. Results The fungal infection rate after liver transplantation is 13.5% (120/886) and the case fatality rate reaches 70.8%; most are infected by Candida albicans (67.5%), with infection located in the lung (73.3%). Acute physiology and chronic health evaluation scores of the infected group are higher than those of the control group 24 hours after the surgery (27.1±5.2 vs. 21.9±5.0). The percentage of primary liver cancer patients in the infected group was lower than in the control group (26.7% vs. 45.8%). Compared to the control group, the infected group had a higher percentage of patients with HBV, gestational diabetes mellitus, and multiple organ dysfunction syndrome. Percentages of patients with long continuous parenteral nutrition time, poorly controlled high blood sugar, long-term mechanical ventilation, and antibiotics use were higher in the infected group than in the control group. Conclusions Preoperative original attack, postoperative critical condition, chronically high blood sugar, long-term use of antibiotics, and mechanical ventilation are probably vital risk factors for fungal infection after liver transplantation.

Background and objective: The relationship between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism and renal allograft survival after renal transplantation from the published reports are still debatable. This study was performed to evaluate the relationship between the ACE I/D gene polymorphism and renal allograft survival after renal transplantation using meta-analysis. Method: Eligible studies were identified from PubMed and Cochrane Library on 1 November 2014, and eligible studies were recruited and synthesized using a meta-analysis methodology. Results: Twelve investigations were included in this meta-analysis for the assessment of the relationship between the ACE I/D gene polymorphism and renal allograft survival. In this meta-analysis, the ACE I/D gene polymorphism was not associated with renal allograft survival after renal transplantation for overall populations, Caucasians, Brazilians and Africans. Interestingly, the ACE D allele and DD genotype were associated with renal allograft survival after renal transplantation in the Asian population. Conclusions: ACE D allele and DD genotype were associated with renal allograft survival after renal transplantation in the Asian population. However, more studies should be performed to confirm this association.

Results on the relationship between CTLA4 -318C/T (rs5742909) gene polymorphism and risk of acute rejection in renal transplantation are still conflicting. This meta-analysis was performed to update the association between CTLA4 -318C/T and risk of acute rejection in renal transplantation. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Twelve reports were included in this meta-analysis for the association of CTLA4 -318C/T gene polymorphism with acute rejection risk in renal transplantation, consisting of 728 acute rejection patients and 1628 non-acute rejection controls. The association between CTLA4 -318C/T gene polymorphism and acute rejection risk in renal transplantation for overall populations was not found in this meta-analysis (T allele: OR=0.96, 95% CI: 0.60-1.54, P=.88; TT genotype: OR=0.90, 95% CI: 0.47-1.71, P=.74; CC genotype: OR=1.00, 95% CI: 0.62-1.59, P=.98). Interestingly, T allele was associated with the risk of acute rejection in renal transplantation in African population. In conclusion, CTLA4 -318C/T gene polymorphism is not associated with the risk of acute rejection in renal transplantation in overall populations.

The conclusions on the association between cytotoxic T-lymphocyte antigen 4 (CTLA4) +49A/G gene polymorphism and acute rejection risk in renal transplantation are still debated. This meta-analysis was performed to update the association between CTLA4 +49A/G and acute rejection risk in renal transplantation. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Fourteen reports were included into this meta-analysis for the association of CTLA4 A/G gene polymorphism and acute rejection risk in renal transplantation, consisting of 962 acute rejection patients and 2084 non-acute rejection controls. The association between CTLA4 G allele/GG genotype and acute rejection risk in renal transplantation was found in this meta-analysis (G allele: OR=1.21, 95% CI: 1.03-1.44, P=.02; GG genotype: OR=1.37, 95% CI: 1.10-1.69, P=.004). However, the AA genotype was not associated with acute rejection risk in renal transplantation. In conclusion, CTLA4 G allele/GG genotype is associated with the acute rejection risk in renal transplantation.

To explore the risk factors of fungal infection so as to provide rationales for the prevention of fungal infection after liver transplantation.The clinical data of 94 cases of fungal infections after liver transplantation from January 1, 2003 to November 30, 2010 at our hospital were collected as the infective group. A total of 603 liver transplant patients without fungal infections during the same period were selected as the control group. χ(2) test and t test were utilized for the analysis of possible risk factors for fungal infection.Fungal infection rate was 13.5% (94/697) after liver transplantation and mortality rate of fungal infection 86.2% (81/94). Candida albicans was the majority infective fungi. And the main site of infection was the lungs. The postoperative acute physiology and chronic health evaluation III (APACHE III) score of the infective group was significantly higher than that of the control group (26.0 ± 5.4 vs 21.5 ± 4.7, P0.01). The number of patients with primary liver cancer was lower than that of the control group (26.6% vs 45.8%, P0.01). The number of decompensated HBV cirrhosis and diabetics in the infective group was higher than that of the control group at pre-operation (23.4% vs 11.6%, 9.6% vs 2.8%, both P0.01). The number of patients with postoperative mechanical ventilation over 10 days, postoperative antibiotics over 14 days, postoperative cardiopulmonary dysfunction and liver function recovery time over 7 days, parenteral nutrition over 12 days and hyperglycemia over 7 days in the infective group were significantly higher than that in the control group (all P0.01).Preoperative primary disease, postoperative disease severity, postoperative organ dysfunction, long-term mechanical ventilation, antibiotics and hyperglycemia, etc. may be the important risk factors of fungal infection after liver transplantation.