Changes in global land surface frozen ground and freeze-thaw processes during 1950-2020 based on ERA5-Land data

Frozen ground(FG)plays an important role in global and regional climates and environments through changes in land freeze-thaw processes,which have been conducted mainly in different regions.However,the changes in land surface freeze-thaw processes under climate change on a global scale are still unclear.Based on ERA5-Land hourly land skin temperature data,this study evaluated changes in the global FG area,global land surface first freeze date(FFD),last freeze date(LFD)and frost-free period(FFP)from 1950 to 2020.The results show that the current FG areas(1991-2020 mean)in the Northern Hemisphere(NH),Southern Hemisphere(SH),and globe are 68.50×10^(6),9.03×10^(6),and 77.53×10^(6)km^(2),which account for 72.4%,26.8%,and 60.4%of the exposed land(excluding glaciers,ice sheets,and water bodies)in the NH,SH and the globe,respectively;further,relative to 1951-1980,the FG area decreased by 1.9%,8.8%,and 2.8%,respectively.Seasonally FG at lower latitudes degrades to intermittently FG,and intermittently FG degrades to non-frozen ground,which caused the global FG boundary to retreat to higher latitudes from 1950 to 2020.The annual FG areas in the NH,SH,and globe all show significant decreasing trends(p<0.05)from 1950 to 2020 at-0.32×10^(6),-0.22×10^(6),and-0.54×10^(6)km^(2)per decade,respectively.The FFP prolongation in the NH is mainly influenced by LFD advance,while in the SH it is mainly controlled by FFD delay.The prolongation trend of FFP in the NH(1.34 d per decade)is larger than that in the SH(1.15 d per decade).

Thyrotoxicosis Occurring in Secondary Hyperparathyroidism Patients Undergoing Dialysis after Total Parathyroidectomy with Autotransplantation

Secondary hyperparathyroidism （SHPT） is a common complication in chronic kidney disease （CKD） that is characterized by excessive synthesis of parathyroid hormone （PTH） and parathyroid hyperplasia.The prevalence of CKD is estimated to be 5-10%, and the burden of CKD-associated diseases is alarmingly high.Despite advances in medical therapy for SHPT, surgical parathyroidectomy remains the definitive therapy for refractory SHPT, which drastically decreases PTH levels and ameliorates symptoms related to severe SHPT.

Quorum sensing inhibition of hordenine analogs on Pseudomonas aeruginosa and Serratia marcescens

Quorum sensing(QS)plays an essential role in virulence factor production,biofilm formation,and antimicrobial resistance.As a potent QS inhibitor,hordenine can inhibit both QS and biofilm formation in Pseudomonas aeruginosa and Serratia marcescens.In this work,we tested the QS inhibitory potential of 27 hordenine analogs against QS and biofilm formation in P.aeruginosa and S.marcescens.Among the tested analogs,seven(12,28,27,26,2,23,and 7)exhibited strong QS inhibitory activity against P.aeruginosa,five of which(12,28,27,26,and 2)showed better inhibitory activity than hordenine.In addition,seven analogs(28,12,23,7,26,2,and 27)exhibited better biofilm inhibition against P.aeruginosa than hordenine.Four analogs(7,28,2,and 12)showed QS inhibitory activity against S.marcescens,two of which(7 and 28)demonstrated better inhibitory activity than hordenine.Furthermore,analog 7 showed similar biofilm inhibition against S.marcescens as hordenine.Structure-activity relationship(SAR)analysis indicated that the inhibitory activities of the analogs were related to four factors,i.e.,carbon chain length,presence or absence of anα,β-C=C bond,amino group with/without lipophilic group,such as methyl group,and hydroxyl group in benzene ring.

A Novel Antiviral Treatment of Hepatitis C Virus Reactivation in a Breast Cancer Patient Undergoing Chemotherapy

To the Editor： Viral hepatitis is a major public health concern worldwide, and hepatitis B virus （HBV）, with which two billion people infected globally, has been commonly reported to undergo reactivation during chemotherapy for malignancies. Some literatures have reported hepatitis C virus （HCV） reactivationin hematological malignancies.