Hemicellulose in corn straw:Extracted from alkali solution and produced5-hydroxymethyl furfural in HCOOH/HCOONa buffer solution

Hemicellulose in corn straw is a group of complex heteropolysaccharides which are composed of different sugar units, including mannans, xylans, arabinans and galactans. This study developed a simple and practical process for production of 5-hydroxymethyl furfural(HMF) using hemicellulose that was extracted from corn straw. In the hemicellulose degradation process HCOOH/HCOONa was used as buffer solution, and the optimum conditions for maximum HMF yield were explored. Various extraction conditions including NaOH concentration, reaction time,temperature, solid-to-liquid ratio and precipitant were tested for hemicellulose obtaining, giving the optimum condition of 55 °C, 4 h, solid-to-liquid ratio of 1:10, 1.5 mol·L^(-1) NaOH solution and ethanol as precipitant with the yield of 34.16%. Dehydration of hemicellulose under HCOOH/HCOONa buffer solution process, using solution medium of pH = 0.8 hydrolyzed hemicellulose in corn straw at 190 °C after 190 min and 82% of HMF yield was achieved.

Porewater-derived dissolved inorganic carbon and nutrient fluxes in a saltmarsh of the Changjiang River Estuary

Saltmarshes are one of the most productive ecosystems,which contribute significantly to coastal nutrient and carbon budgets.However,limited information is available on soil nutrient and carbon losses via porewater exchange in saltmarshes.Here,porewater exchange and associated fluxes of nutrients and dissolved inorganic carbon(DIC)in the largest saltmarsh wetland(Chongming Dongtan)in the Changjiang River Estuary were quantified.Porewater exchange rate was estimated to be(37±35)cm/d during December 2017 using a radon(^(222)Rn)mass balance model.The porewater exchange delivered 67 mmol/(m^(2)·d),38 mmol/(m^(2)·d)and 2690 mmol/(m^(2)·d)of dissolved inorganic nitrogen(DIN),dissolved silicon(DSi)and DIC into the coastal waters,respectively.The dominant species of porewater DIN was NH_(4)^(+)(>99%of DIN).However,different with those in other ecosystems,the dissolved inorganic phosphorus(DIP)concentration in saltmarsh porewater was significantly lower than that in surface water,indicating that saltmarshes seem to be a DIP sink in Chongming Dongtan.The porewater-derived DIN,DSi and DIC accounted for 12%,5%and 18%of the riverine inputs,which are important components of coastal nutrient and carbon budgets.Furthermore,porewater-drived nutrients had obviously high N/P ratios(160–3995),indicating that the porewater exchange process may change the nutrient characteristics of the Changjiang River Estuary and further alter the coastal ecological environment.

Submarine groundwater discharge enhances primary productivity in the Yellow Sea, China: Insight from the separation of fresh and recirculated components

Submarine groundwater discharge(SGD)is being increasingly recognized as a significant source of nutrient into coastal waters,and generally comprises two components:submarine fresh groundwater discharge(SFGD)and recirculated saline groundwater discharge(RSGD).The separate evaluation of SFGD and RSGD is extremely limited as compared to the conventional estimation of total SGD and associated nutrient fluxes,especially in marginal-scale regions.In this study,new high-resolution radium isotopes data in seawater and coastal groundwater enabled an estimation of SGD flux in a typical marginal sea of the Yellow Sea.By establishing 226Ra and 228Ra mass balance models,we obtained the SGD-derived radium fluxes,and then estimated the SFGD and RSGD fluxes through a two end-member model.The results showed that the total SGD flux into the Yellow Sea was equivalent to approximately 6.6 times the total freshwater discharge of surrounding rivers,and the SFGD flux accounted for only 5.2%–8.8%of the total SGD.Considering the nutrient concentrations in coastal fresh and saline groundwater,we obtained the dissolved inorganic nutrient fluxes(mmol m^(-2) yr^(-1))to be 52–353 for nitrogen(DIN),0.21–1.4 for phosphorus(DIP),34–226 for silicon(DSi)via SFGD,and 69–262 for DIN,1.0–3.9 for DIP,70–368 for DSi via RSGD,with the sum of nutrient fluxes equaling to(1.8–9.3)-fold,(1.3–5.6)-fold and(2.0–9.5)-fold of the riverine inputs.Compared to the conventional estimation of the total SGD flux,the nutrient fluxes derived from the separation of SFGD and RSGD were(1.6–2.1),(1.6–1.8)and(4.0–4.9)times lower for DIN,DIP and DSi,respectively,indicating that the estimates by separating SFGD and RSGD could be conservative and representative results of the Yellow Sea.Furthermore,we suggested that SGD played an important role in nutrient sources among all the traditional nutrient inputs sources,providing 15%–48%,33%–68%and 14%–43%of the total DIN,DIP and DSi input fluxes into the Yellow Sea,and the high nutrient stoichiometric ratios(i.e.,DIN/DIP)in SGD probably contributed to the increasing ratios in the Yellow Sea.In addition delivering large amounts of nutrient into the Yellow Sea,SGD would create primary productivity of 10–49,1.6–6.8 and 8.8–42 g C m^(-2)yr^(-1) based on N,P and Si,which were equivalent to 5.2%–27%,0.9%–3.7%and 4.7%–23%of the total primary productivity,respectively.In particular,the SFGD-derived DIN flux can be converted to primary productivity of 4.2–28 g C m^(-2)yr^(-1) thus demonstrating the disproportionately large role of SFGD in ecological environment of the Yellow Sea relative to its flux.Therefore,we conclude that SGD,particularly SFGD,plays an important role as a nutrient source for the Yellow Sea,and not only affects nutrient budgets and structures but also enhances the primary productivity.

Mediation of serum albumin in the association of serum potassium with mortality in Chinese dialysis patients:a prospective cohort study

Background: The clinical importance of hypokalemia is likely underrecognized in Chinese dialysis patients, and whether its clinical effect was mediated by serum albumin is not fully elucidated. This study aimed to explore the association between serum potassium and mortality in dialysis patients of a Chinese nationwide multicenter cohort, taking albumin as a consideration. Methods: This was a prospective nation-wide multicenter cohort study. Restricted cubic splines were used to test the linearity of serum potassium and relationships with all-cause (AC) and cardiovascular (CV) mortality and a subsequent two-line piecewise linear model was fitted to approach the nadir. A mediation analysis was performed to examine relations of albumin to potassium and mortalities. Results: A total of 10,027 patients were included, of whom 6605 were peritoneal dialysis and 3422 were hemodialysis patients. In the overall population, the mean age was 51.7 ± 14.8 years, 55.3%(5546/10,027) were male, and the median dialysis vintage was 13.60 (4.70, 39.70) months. Baseline serum potassium was 4.30 ± 0.88 mmol/L. After a median follow-up period of 26.87 (14.77, 41.50) months, a U-shape was found between potassium and mortality, and a marked increase in risk at lower potassium but a moderate elevation in risk at higher potassium were observed. The nadir for AC mortality risk was estimated from piecewise linear models to be a potassium concentration of 4.0 mmol/L. Interestingly, the significance of the association between potassium and mortality was attenuated when albumin was introduced into the extended adjusted model. A subsequent significant mediation by albumin for potassium and AC and CV mortalities were found ( P < 0.001 for both), indicating that hypokalemia led to higher mortality mediated by low serum albumin, which was a surrogate of poor nutritional status and inflammation. Conclusions: Associations between potassium and mortalities were U-shaped in the overall population. The nadir for AC mortality risk was at a potassium of 4.0 mmol/L. Serum albumin mediated the association between potassium and AC and CV mortalities.

SARS-CoV-2 N protein induces acute kidney injury in diabetic mice via the Smad3-Ripk3/MLKL necroptosis pathway

Dear Editor,Kidney is one of major organs attacked by SARS-CoV-2,resulting in acute kidney injury(AKI)in critically ill COVID-19 patients,especially in the elderly and diabetic patients with diabetic kidney disease(DKD).1,2 Among SARS-CoV-2 proteins,the N protein can be detectable in damaged tubules in COVID-19 patients with AKI.

Randomized controlled multicenter clinical trial for integrated treatment of community-acquired pneumonia based on Traditional Chinese Medicine syndrome differentiation

OBJECTIVE:To evaluate the efficacy and safety of treatment based on syndrome differentiation ofTraditional Chinese Medicine(TCM) for community-acquired pneumonia(CAP).METHODS:A total of 240 CAP patients were randomly divided into the following two groups:thecontrol group was treated by anti-infection plus conventional medicine treatment;and the trial group was treated by TCM plus the above-mentioned treatment given to the controls.The course of treatment was 14 days,and the patients were followed up for 7 days.RESULTS:Of the 240 patients,235 accomplished the whole process of treatment.The five patients who withdrew from the study were brought into an intent-to-treat analysis.The therapeutic effects of the trial group were superior to those of the control group(P<0.01).The trial group took less time to become clinically stable,with a higher score in the quality of life(P<0.01).There were no significant differences in mortality rate(P>0.05),white blood cell count(P>0.05),bacterial clearance rate(P>0.05),and adverse reactions between the two integrated groups.CONCLUSION:Treatment based on TCM syndrome differentiation for CAP has the advantages of resulting in less time to achieve a stable clinical condition,improvement of clinical symptoms and quality of life,and is comparatively safe.

Antibody upstream sequence diversity and its biological implications revealed by repertoire sequencing

The sequence upstream of the antibody variable region(antibody upstream sequence[AUS])consists of a 5′untranslated region(5′UTR)and a preceding leader region.The sequence variations in AUS affect antibody engineering and PCR based antibody quantification and may also be implicated in mRNA transcription and translation.However,the diversity of AUSs remains elusive.Using 5′rapid amplification of cDNA ends and high-throughput antibody repertoire sequencing technique,we acquired full-length AUSs for human,rhesus macaque,cynomolgus macaque,mouse,and rat.We designed a bioinformatics pipeline and identified 3307 unique AUSs,corresponding to 3026 and 1457 unique sequences for 5′UTR and leader region,respectively.Comparative analysis indicated that 928(63.69%)leader sequences are novel relative to those recorded in the international ImMunoGeneTics information system.Evolutionarily,leader sequences are more conserved than 5′UTR and seem to coevolve with their downstream V genes.Besides,single-nucleotide polymorphisms are position dependent for leader regions and may contribute to the functional reversal of the downstream V genes.Finally,the AUGs in AUSs were found to have little impact on gene expression.Taken together,our findings can facilitate primer design for capturing antibodies efficiently and provide a valuable resource for antibody engineering and molecule-level antibody studies.

DQB1＊060101 may contribute to susceptibility to immunoglobulin A nephropathy in southern Han Chinese

Immunoglobulin A nephropathy （IgAN） is a common form of chronic glomerulonephritis with unknown pathogenesis. Accumulating evidences have shown the ethnic-specific association between certain human leukocyte antigen （HLA） alleles and IgAN susceptibility. This study was designed to explore the relationship between HLA-DQB1 alleles and disease susceptibility and clinical manifestations of patients with IgAN in southern Han Chinese. A PCR sequence-based typing technique was used to detect HLA-DQB1 alleles in 217 IgAN patients and 229 healthy subjects. Clinical data were collected from each patient at the time of renal biopsy. Twenty HLA-DQB1 alleles were detected in IgAN patients and healthy subjects. High frequency of HLA- DQB1＊060101 and low frequency of HLA-DQB1＊030101 were observed in IgAN patients compared with healthy controls. Further stratification analysis revealed that the frequency of DQB1＊060101 was significantly higher in patients with urine protein ≥1.0 g/24 h than in patients with urine protein 〈 1.0 g/24 h. In combination with our previous DRB1 results, we also analyzed the association of DRB1-DQB1 haplotypes with IgAN. We found that the frequency of haplotype DRBI＊090102-DQB1＊060101 was significantly higher [odds ratio （OR） = 4.409, Pc = 0.016], whereas that of HLA-DRBI＊070101-DQB1＊020101 was significantly lower （OR= 0.194, Pc = 0.016） compared with healthy controls. Our study indicated that HLA-DQB ＊060101 alleles may be a potential predictor of high-risk IgAN susceptibility in Chinese Han population.