Vegetation-fire feedbacks increase subtropical wildfire risk in scrubland and reduce it in forests

Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland-forest stabilized by vegetation-fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation-fire feedbacks; in forest, vegetation-fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation-fire feedbacks that suppress wildfire.

Use of Extracorporeal Membrane Oxygenation for Primary Graft Dysfunction After Cardiac Transplantation: Results of an A Priori Ventless Approach

Primary graft dysfunction (PGD) after cardiac transplantation is a devastating complication with increasing frequency lately in the setting of donation after circulatory death (DCD). Severe PGD is commonly treated with extracorporeal membrane oxygenation (ECMO) using central or peripheral cannulation. We retrospectively reviewed the outcomes of PGD after cardiac transplantation requiring ECMO support at our center from 2015 to 2020, focused on our now preferential approach using peripheral cannulation without a priori venting. During the study period, 255 patients underwent heart transplantation at our center and 26 (10.2%) of them required ECMO for PGD. Of 24 patients cannulated peripherally 19 (79%) were alive at 30 days and 17 (71%) 1 year after transplant; two additional patients underwent central ECMO cannulation due to unfavorable size of femoral vessels and concern for limb ischemia. Successful decannulation with full graft function recovery occurred in 22 of 24 (92%) patients cannulated peripherally. Six of them had an indwelling intra-aortic balloon pump placed before the transplantation. None of the other 18 patients received a ventricular vent. In conclusion, the use of an a priori peripheral and ventless ECMO approach in patients with PGD after heart transplant is an effective strategy associated with high rates of graft recovery and survival.

A comparative evaluation of chemical composition and antimicrobial activities of essential oils extracted from different chemotypes of Cinnamomum camphora (L.) Presl

The purpose of this study is to determine the chemical composition of the essential oils of Cinnamomum camphora (L.) Presl leaves (CCPL) from 5 different habitats in China by GC-MS, and to evaluate their antimicrobial activities against 3 foodborne pathogens, using a paper disc diffusion method. A total of 30 compounds were identified with a predominance of oxygenated monoterpenes, including linalool (42.65%-96.47%), eucalyptol (39.07%-55.35%) and camphor (26.08%) as well as monoterpene hydrocarbons such as sabinene (6.18%-12.93%) and α-terpineol (8.19%-13.81%). Through cluster analysis, CCPL from 5 different habitats can be well divided into 2 categories. Combining with principal component analysis, the habitats can be better correlated with the chemical constituents of the essential oils. The antimicrobial activities of 5 extracted essential oils against 2 gram-negative bacteria and one gram-positive bacteria were assessed. It showed that the essential oil extracted from the CCPL harvested in Jinxi had the strongest antibacterial property. The results of this study provided basis for resource identification of CCPL and quality difference identification of essential oils. Research on the antibacterial properties of several pathogenic strains has proved its application value as a natural food preservative.

Cardiac Imaging With 123I-meta-iodobenzylguanidine and Analogous PET Tracers: Current Status and Future Perspectives

Autonomic innervation plays an important role in proper functioning of the cardiovascular system. Altered cardiac sympathetic function is present in a variety of diseases, and can be assessed with radionuclide imaging using sympathetic neurotransmitter analogues. The most studied adrenergic radiotracer is cardiac ¹²³I-meta-iodobenzylguanidine (¹²³I-mIBG). Cardiac ¹²³I-mIBG uptake can be evaluated using both planar and tomographic imaging, thereby providing insight into global and regional sympathetic innervation. Standardly assessed imaging parameters are the heart-to-mediastinum ratio and washout rate, customarily derived from planar images. Focal tracer deficits on tomographic imaging also show prognostic utility, with some data suggesting that the best approach to tomographic image interpretation may differ from conventional methods. Cardiac ¹²³I-mIBG image findings strongly correlate with the severity and prognosis of many cardiovascular diseases, especially heart failure and ventricular arrhythmias. Cardiac ¹²³I-mIBG imaging in heart failure is FDA approved for prognostic purposes. With the robustly demonstrated ability to predict occurrence of potentially fatal arrhythmias, cardiac ¹²³I-mIBG imaging shows promise for better selecting patients who will benefit from an implantable cardioverter defibrillator, but clinical use has been hampered by lack of the randomized trial needed for incorporation into societal guidelines. In patients with ischemic heart disease, cardiac ¹²³I-mIBG imaging aids in assessing the extent of damage and in identifying arrhythmogenic regions. There have also been studies using cardiac ¹²³I-mIBG for other conditions, including patients following heart transplantation, diabetic related cardiac abnormalities and chemotherapy induced cardiotoxicity. Positron emission tomographic adrenergic radiotracers, that improve image quality, have been investigated, especially ¹¹C-meta-hydroxyephedrine, and most recently ¹⁸F-fluorbenguan. Cadmium-zinc-telluride cameras also improve image quality. With better spatial resolution and quantification, PET tracers and advanced camera technologies promise to expand the clinical utility of cardiac sympathetic imaging.

Outcomes of ≤6-month versus 12-month dual antiplatelet therapy after drug-eluting stent implantation: A meta-analysis and meta-regression

BACKGROUND

The benefit of ≤6-month compared with 12-month dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) placement remains controversial. We performed a meta-analysis and meta-regression of ≤6-month versus 12-month DAPT in patients undergoing PCI with DES placement.

METHODS

We conducted electronic database searches of randomized controlled trials (RCTs) comparing DAPT durations after DES placement. For studies with longer follow-up, outcomes at 12 months were identified. Odds ratios and 95% confidence intervals were computed with the Mantel-Haenszel method. Fixed-effect models were used; if heterogeneity (I) > 40 was identified, effects were obtained with random models.

RESULTS

Nine RCTs were included with total n = 19,224 patients. No significant differences were observed between ≤6-month compared with 12-month DAPT in all-cause mortality (OR 0.87; 95% confidence interval (CI): 0.69-1.11), cardiovascular (CV) mortality (OR 0.89; 95% CI: 0.66-1.21), non-CV mortality (OR 0.85; 95% 0.58-1.24), myocardial infarction (OR 1.10; 95% CI: 0.89-1.37), stroke (OR 0.97; 95% CI: 0.67-1.42), stent thrombosis (ST) (OR 1.37; 95% CI: 0.89-2.10), and target vessel revascularization (OR 0.95; 95% CI: 0.77-1.18). No significant difference in major bleeding (OR 0.72; 95% CI: 0.49-1.05) was observed, though the all-bleeding event rate was significantly lower in the ≤6-month DAPT group (OR 0.76; 95% CI: 0.59-0.96). In the meta-regression analysis, a significant association between bleeding events and non-CV mortality with 12-month DAPT was found, as well as between ST and mortality in addition to MI with ≤6-month DAPT.

CONCLUSION

DAPT for ≤6 months is associated with similar mortality and ischemic outcomes but less bleeding events compared with 12-month DAPT after PCI with DES.

Non-Hodgkin lymphoma mimics retroperitoneal fibrosis

A 33-year-old man presented with lymphoedema and obstructive nephropathy and was first diagnosed as retroperitoneal fibrosis (RF) with consistent clinical picture and radiographic findings. Further CT-guided biopsy was performed and non-Hodgkin lymphoma was diagnosed based on pathological results. RF is usually diagnosed through clinical presentation and imaging studies. However, our case proved that biopsy should be considered to exclude malignancy, even with typical presentations of RF. Follow-up after six courses of R-CHOP (rituximab, cyclophosphamide, vindesine, epirubicin and prednisone) regimen revealed complete resolution of symptoms.

Depressive symptoms, cortisol, and cognition during human aging: the role of negative aging perceptions

Depressive symptoms and memory impairments are associated with heightened stress hormone levels during aging. A factor that is related to memory deficits during aging is internalized negative aging stereotypes; the idea people have about the process of aging. In this study, we assessed the associations between internalized negative aging stereotypes, depressive symptoms, subjective and objective memory assessments, and cortisol concentration among older adults. Forty older adults aged between 58 and 85 years (18 females and 22 males; mean age ± SD: 71.25 ± 8.80 years) were assessed in this study. Measures of internalized negative aging stereotypes, depressive symptoms, and both subjective and objective memory performance were assessed. Salivary samples were obtained for measurement of cortisol concentration. Stepwise linear regressions were executed in our main analyses. Internalized negative aging stereotypes were associated with increased depressive symptoms and subjective memory complaints. No significant differences were observed for objective memory performance, or cortisol concentration. Internalized negative aging stereotypes are associated with increased depressive symptomatology and subjective complaints of memory; however, they do not predict increased cortisol concentration nor objective memory performance during aging. These results indicate that the mechanism underlying the association between internalized negative aging stereotypes and cognitive impairments may not be related to dysregulations of cortisol secretion among older adults.

Cigarette smoke exposure hinders long-term allograft survival by suppressing indoleamine 2, 3-dioxygenase expression

Cigarette smoke causes cancer and increases the vulnerability of smokers to infections. Epidemiologic studies have shown that smoking is one of major risk factors for late allograft rejection. Despite statistical data that associate smoking with allograft rejection, no any study has been conducted to prove that cigarette smoke directly causes allograft rejection in a cause-effect manner. In particular, investigation into immunologic mechanisms underlying smoke-related allograft rejection is lacking. Here we found that second hand smoke (SHS) hindered long-term islet allograft survival induced by CD154 costimulatory blockade plus donor-specific splenocyte transfusion (DST), although it failed to alter acute islet allograft rejection. SHS did not directly interfere with vigorously alloreactive T-cell proliferation in vivo and in vitro. Neither naturally occurring nor induced CD4+CD25+ Treg cell numbers were significantly reduced by SHS. However, SHS suppressed mRNA and protein expression of indoleamine 2, 3-dioxygenase (IDO) and its activity upon transplantation while IDO overexpression in islet allografts restored their long-term survival induced by CD154 blockade. Therefore, SHS prevents long-term allograft survival by inhibiting IDO expression and activity. Thus, our study for the first time demonstrates that SHS shortens allograft survival in a cause-effect manner and unveils a novel immunologic mechanism underlying smoking-related allograft rejection.

Electroluminescent devices based on amorphous SiN/Si quantum dots/amorphous SiN sandwiched structures

A single layer of dense Si quantum dots with average size of 4 nm sandwiched in amorphous SiN layers was prepared by laser crystallization of ultrathin amorphous Si film followed by subsequently thermal annealing. The electroluminescent diodes were fabricated by evaporating Al electrodes on back sides of p-Si substrates and the top surface of samples. Room temperature electroluminescence can be detected with applying the negative voltage around 10V on the top gate electrode and the luminescent intensity is increased with increasing the applied voltage. It was found that the integrated luminescent intensity is linearly proportional to the injection current which suggested the intensity depends on the concentrations of injected carriers after Fowler-Nordheim tunneling through amorphous SiN barriers. The influence of the amorphous SiN with different band gap on the device performance was also discussed briefly.

Annual dynamics and origins of the odorous compounds in the pilot experimental area of Lake Dianchi, China

Lake Dianchi is the sixth largest freshwater lake in China. The pilot experimental area (6 km2) in Lake Dianchi is one of the most severely polluted areas in the lake with heavy cyanobacteria blooms. During June 2002 to May 2003, the algal composition and number, and odorous compounds were identified monthly and monitored in the area. Meanwhile, physicochemical parameters such as total phosphorus (TP), total nitrogen (TN), 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD(Mn)), dissolved oxygen (DO), pH, transparency, temperature and chlorophyll a (chla) were determined. Four odorous compounds: 2-methylisoborneol (MIB), geosmin, beta-cyclocitral and beta-ionone were found in the lake water. Both the concentration of particulate beta-cyclocitral and that of beta-ionone correlated significantly with the annual variation of Chla, biomass of total phytoplankton, cyanobacteria and Microcystis. The concentration of particulate MIB correlated significantly with the biomass of Oscillatoria, while the concentration of particulate geosmin correlated significantly with the biomass of Anabaena. Off-flavour in the pilot area was found to be caused by a combination of beta-cyclocitral- and beta-ionone-producing Microcystis, MIB-producing Oscillatoria and geosmin-producing Anabaena. beta-ionone, MIB and geosmin contributed collectively to the odour intensity in the lake water.

Successful ageing: from cell to self

Many people see ageing as a time of cognitive and physical decline. For the past three decades, most scientists and the general public have accepted this negative age-stereotype as the norm, but fortunately this view is now challenged. New findings show that well-being and a positive view of ageing are major protective factors against the effects of age on the organism. These results challenge the scientific studies that place emphasis on the negative side of ageing. This ageism view has been observed in each sphere of science, from genetics to social sciences. Perspectives from each domain are described, and new integrative views of successful ageing are summarized.

[The medium optimization of xylitol fermentation based on neural networks and genetic algorithms]

Using genetic algorithms(GA) for medium optimization of xylitol fermentation, and coupling neural networks model for predicting xylitol concentration is introduced. The medium compose determined by GA is as input data of the neural networks, while the output data predicted by neural networks is as suitable value of GA for predicting. The optimum medium is further validated by experimentation. The good result, which save the experimental workload and charge, enhance the level of xylitol fermentation as well as reduced the medium consume is obtained.