Heterogeneously elevated branched-chain/aromatic amino acids among new-onset type-2 diabetes mellitus patients are potentially skewed diabetes predictors

BACKGROUND The lack of specific predictors for type-2 diabetes mellitus(T2DM)severely impacts early intervention/prevention efforts.Elevated branched-chain amino acids(BCAAs:Isoleucine,leucine,valine)and aromatic amino acids(AAAs:Tyrosine,tryptophan,phenylalanine)show high sensitivity and specificity in predicting diabetes in animals and predict T2DM 10-19 years before T2DM onset in clinical studies.However,improvement is needed to support its clinical utility.AIM To evaluate the effects of body mass index(BMI)and sex on BCAAs/AAAs in new-onset T2DM individuals with varying body weight.METHODS Ninety-seven new-onset T2DM patients(<12 mo)differing in BMI[normal weight(NW),n=33,BMI=22.23±1.60;overweight,n=42,BMI=25.9±1.07;obesity(OB),n=22,BMI=31.23±2.31]from the First People’s Hospital of Yunnan Province,Kunming,China,were studied.One-way and 2-way ANOVAs were conducted to determine the effects of BMI and sex on BCAAs/AAAs.RESULTS Fasting serum AAAs,BCAAs,glutamate,and alanine were greater and high-density lipoprotein(HDL)was lower(P<0.05,each)in OB-T2DM patients than in NW-T2DM patients,especially in male OB-T2DM patients.Arginine,histidine,leucine,methionine,and lysine were greater in male patients than in female patients.Moreover,histidine,alanine,glutamate,lysine,valine,methionine,leucine,isoleucine,tyrosine,phenylalanine,and tryptophan were significantly correlated with abdominal adiposity,body weight and BMI,whereas isoleucine,leucine and phenylalanine were negatively correlated with HDL.CONCLUSION Heterogeneously elevated amino acids,especially BCAAs/AAAs,across new-onset T2DM patients in differing BMI categories revealed a potentially skewed prediction of T2DM development.The higher BCAA/AAA levels in obese T2DM patients would support T2DM prediction in obese individuals,whereas the lower levels of BCAAs/AAAs in NW-T2DM individuals may underestimate T2DM risk in NW individuals.This potentially skewed T2DM prediction should be considered when BCAAs/AAAs are to be used as the T2DM predictor.

Interplay of serum biomarkers bilirubin andγ-glutamyltranspeptidase in predicting cardiovascular complications in type-2 diabetes mellitus

This editorial synthesizes insights from a series of studies examining the interplay between metabolic and oxidative stress biomarkers in cardiovascular disease(CVD),focusing particularly on type-2 diabetes mellitus(T2DM)and acute coronary syndrome(ACS).The central piece of this synthesis is a study that investigates the balance between oxidative stress and antioxidant systems in the body through the analysis of serum bilirubin andγ-glutamyltranspeptidase(γ-GGT)levels in T2DM patients with ACS.This study highlights serum bilirubin as a protective antioxidant factor,while elevatedγ-GGT levels indicate increased oxidative stress and correlate with major adverse cardiovascular events.Complementary to this,other research contributions revealγ-GGT’s role as a risk factor in ACS,its association with cardiovascular mortality in broader populations,and its link to metabolic syndrome,further elucidating the metabolic dysregulation in CVDs.The collective findings from these studies underscore the critical roles ofγ-GGT and serum bilirubin in cardiovascular health,especially in the context of T2DM and ACS.By providing a balanced view of the body’s oxidative and antioxidative mechanisms,these insights suggest potential pathways for targeted interventions and improved prognostic assessments in patients with T2DM and ACS.This synthesis not only corroborates the pivotal role ofγ-GGT in cardiovascular pathology but also introduces the protective potential of antioxidants like bilirubin,illuminating the complex interplay between T2DM and heart disease.These studies collectively underscore the critical roles of serum bilirubin andγ-GGT as biomarkers in cardiovascular health,particularly in T2DM and ACS contexts,offering insights into the body’s oxidative and antioxidative mechanisms.This synthesis of research supports the potential of these biomarkers in guiding therapeutic strategies and improving prognostic assessments for patients with T2DM and some CVD.

Predictive value of bilirubin and serum γ-glutamyltranspeptidase levels in type-2 diabetes mellitus patients with acute coronary syndrome

BACKGROUND Cardiovascular disease is a major complication of diabetes mellitus(DM).Type-2 DM(T2DM)is associated with an increased risk of cardiovascular events and mortality,while serum biomarkers may facilitate the prediction of these outcomes.Early differential diagnosis of T2DM complicated with acute coronary syndrome(ACS)plays an important role in controlling disease progression and improving safety.AIM To investigate the correlation of serum bilirubin andγ-glutamyltranspeptidase(γ-GGT)with major adverse cardiovascular events(MACEs)in T2DM patients with ACS.METHODS The clinical data of inpatients from January 2022 to December 2022 were analyzed retrospectively.According to different conditions,they were divided into the T2DM complicated with ACS group(T2DM+ACS,n=96),simple T2DM group(T2DM,n=85),and simple ACS group(ACS,n=90).The clinical data and laboratory indices were compared among the three groups,and the correlations of serum total bilirubin(TBIL)levels and serumγ-GGT levels with other indices were discussed.T2DM+ACS patients received a 90-day follow-up after discharge and were divided into event(n=15)and nonevent(n=81)groups according to the occurrence of MACEs;Univariate and multivariate analyses were further used to screen the independent influencing factors of MACEs in patients.RESULTS The T2DM+ACS group showed higherγ-GGT,total cholesterol,low-density lipoprotein cholesterol(LDL-C)and glycosylated hemoglobin(HbA1c)and lower TBIL and high-density lipoprotein cholesterol levels than the T2DM and ACS groups(P<0.05).Based on univariate analysis,the event and nonevent groups were significantly different in age(t=3.3612,P=0.0011),TBIL level(t=3.0742,P=0.0028),γ-GGT level(t=2.6887,P=0.0085),LDL-C level(t=2.0816,P=0.0401),HbA1c level(t=2.7862,P=0.0065)and left ventricular ejection fraction(LEVF)levels(t=3.2047,P=0.0018).Multivariate logistic regression analysis further identified that TBIL level and LEVF level were protective factor for MACEs,and age andγ-GGT level were risk factors(P<0.05).CONCLUSION Serum TBIL levels are decreased andγ-GGT levels are increased in T2DM+ACS patients,and the two indices are significantly negatively correlated.TBIL andγ-GGT are independent influencing factors for MACEs in such patients.

Chiglitazar and Thiazolidinedione in patients with type 2 diabetes:Which is better?

This published Meta-Analysis by Lin et al is an indirect comparison between two drugs Chiglitazar and Thiazolidinedione which are commonly used for glycemic control in type-Ⅱ diabetes mellitus.In terms of safety and efficacy,this Meta-Analysis is inconclusive.

Vitamin D,selenium,and antidiabetic drugs in the treatment of type 2 diabetes mellitus with Hashimoto's thyroiditis

BACKGROUND Diabetes and thyroiditis are closely related.They occur in combination and cause significant damage to the body.There is no clear treatment for type-2 diabetes mellitus(T2DM)with Hashimoto's thyroiditis(HT).While single symptomatic drug treatment of the two diseases is less effective,combined drug treatment may improve efficacy.AIM To investigate the effect of a combination of vitamin D,selenium,and hypoglycemic agents in T2DM with HT.METHODS This retrospective study included 150 patients with T2DM and HT treated at The Central Hospital of Shaoyang from March 2020 to February 2023.Fifty patients were assigned to the control group,test group A,and test group B according to different treatment methods.The control group received low-iodine diet guidance and hypoglycemic drug treatment.Test group A received the control treatment plus vitamin D treatment.Test group B received the group A treatment plus selenium.Blood levels of markers of thyroid function[free T3(FT3),thyroid stimulating hormone(TSH),free T4(FT4)],autoantibodies[thyroid peroxidase antibody(TPOAB)and thyroid globulin antibody(TGAB)],blood lipid index[low-density lipoprotein cholesterol(LDL-C),total cholesterol(TC),triacylglycerol(TG)],blood glucose index[fasting blood glucose(FBG),and hemoglobin A1c(HbA1c)]were measured pre-treatment and 3 and 6 months after treatment.The relationships between serum 25-hydroxyvitamin D3[25(OH)D3]level and each of these indices were analyzed.RESULTS The levels of 25(OH)D3,FT3,FT4,and LDL-C increased in the order of the control group,test group A,and test group B(all P<0.05).The TPOAB,TGAB,TC,TG,FBG,HbA1c,and TSH levels increased in the order of test groups B,A,and the control group(all P<0.05).All the above indices were compared after 3 and 6 months of treatment.Pre-treatment,there was no divergence in serum 25(OH)D3 level,thyroid function-related indexes,autoantibodies level,blood glucose,and blood lipid index between the control group,test groups A and B(all P>0.05).The 25(OH)D3 levels in test groups A and B were negatively correlated with FT4 and TGAB(all P<0.05).CONCLUSION The combination drug treatment for T2DM with HT significantly improved thyroid function,autoantibody,and blood glucose and lipid levels.

25-Hydroxyvitamin D Is Associated with Islet Homeostasis in Type-2 Diabetic Patients with Abdominal Obesity

Objective Isletαcells input is essential for insulin secretion fromβcells.The present study aims to investigate the association between 25-hydroxyvitamin D[25(OH)D]and islet function homeostasis in type-2 diabetes(T2D)patients.Methods A total of 4670 T2D patients from seven communities in Shanghai,China were enrolled.The anthropometric indices,biochemical parameters,serum 25(OH)D,and islet function[including C-peptide(C-p)and glucagon]were measured.Results The fasting plasma glucose(FPG),glycated hemoglobin(HbA1c),glucagon,and C-p levels exhibited a significantly decreasing trend in T2D patients as the 25(OH)D levels increased.Next,the population was divided into two groups:abdominal obesity and non-abdominal obesity groups.After adjustment,the 25(OH)D level was found to be associated with HbA1c,glucagon,and homeostasis model assessment ofβ(HOMA-β)in the non-abdominal obesity group.There was a significant relationship between 25(OH)D and HbA1c,glucagon,HOMA-IR,baseline insulin or C-p in the abdominal obesity group.In the abdominal obesity group,the ordinary least squares(OLS)regression and quantile regression revealed that 25(OH)D was obviously associated with glucagon and fasting C-p levels.In the abdominal obesity group,the moderate analysis revealed a significant interaction effect of 25(OH)D and glucagon on C-p(P=0.0124).Furthermore,the conditional indirect effect of 25(OH)D on the glucagon/C-p ratio was significantly lower at 1 standard deviation(SD)below the mean(P=0.0002),and lower at the mean of the course of diabetes(P=0.0007).Conclusion 25(OH)D was found to be negatively correlated to glucagon and C-p in T2D patients with abdominal obesity.The 25(OH)D influenced C-p in part by influencing glucagon.The effect of 25(OH)D on the glucagon/C-p ratio in T2D patients with abdominal obesity,in terms of islet homeostasis,is influenced by the course of diabetes.

State of art on the mechanisms of laparoscopic sleeve gastrectomy in treating type 2 diabetes mellitus

Obesity and type-2 diabetes mellitus(T2DM)are metabolic disorders.Obesity increases the risk of T2DM,and as obesity is becoming increasingly common,more individuals suffer from T2DM,which poses a considerable burden on health systems.Traditionally,pharmaceutical therapy together with lifestyle changes is used to treat obesity and T2DM to decrease the incidence of comorbidities and allcause mortality and to increase life expectancy.Bariatric surgery is increasingly replacing other forms of treatment of morbid obesity,especially in patients with refractory obesity,owing to its many benefits including good long-term outcomes and almost no weight regain.The bariatric surgery options have markedly changed recently,and laparoscopic sleeve gastrectomy(LSG)is gradually gaining popularity.LSG has become an effective and safe treatment for type-2 diabetes and morbid obesity,with a high cost-benefit ratio.Here,we review the mechanism associated with LSG treatment of T2DM,and we discuss clinical studies and animal experiments with regard to gastrointestinal hormones,gut microbiota,bile acids,and adipokines to clarify current treatment modalities for patients with obesity and T2DM.

Bariatric surgery-mediated weight loss and its metabolic consequences for type-2 diabetes

The worldwide epidemic of obesity and its medical complications are being dealt with a combination of life style changes(e.g.,healthier diet and exercise),medications and a variety of surgical interventions.The Roux-en Y gastric bypass(RYGB) and laparoscopic adjustable gastric banding(LAGB) are two of the most common weight loss surgeries for morbid obesityassociated metabolic syndrome and insulin resistance.A vast majority of patients that undergo RYGB and LAGB are known to experience marked weight loss and attenuation of diabetes.A number of recent studies have indicated that the rates of remission in glycemic control and insulin sensitivity are significantly greater in patients that have undergone RYGB.A plausible hypothesis to explain this observation is that the gastric bypass surgery as opposed to the gastric banding procedure impinges on glucose homeostasis by a weight loss-independent mechanism.In a recent paper,Bradley et al have experimentally explored this hypothesis.The authors compared several clinical and laboratory parameters of insulin sensitivity and β-cell function in cohorts of RYGB and LAGB patients before and after they lost approximately 20% of their body mass.Afterweight loss,both groups of patients underwent similar changes in their intra-abdominal and total adipose tissue volume,hepatic triglyceride and circulating leptin levels.The RYGB patients who lost 20% body mass,manifested higher postprandial output of glucose,insulin and glucagon-like peptide-1;these laboratory parameters remained unchanged in LABG patients.Irrespective of the observed differences in transient responses of RYGB and LAGB patients to mixed meal,the overall glycemic control as judged by glucose tolerance,multi-organ insulin sensitivity and β-cell function were nearly identical in the two groups.Both RYGB and LAGB patient cohorts also experienced similar changes in the expression of a number of pro-and anti-inflammatory markers.Based on these analyses,Bradley et al concluded that similar restoration of insulin sensitivity and b-cell function in non-diabetic obese patients that have undergone RYGB and LAGB were directly due to marked weight loss.These data have important implications for the risk/benefit analysis of weight loss therapy by bariatric procedures.

Diabetes self-management (DSM) in Omani with type-2 diabetes

Objective:The aim of this study was to assess the status of diabetes self-management(DSM)among Omanis with type-2 diabetes and its relationship with glycemic control and demographic variables.Methods:A correlational descriptive design using questionnaire was conducted with a convenience sample of 266 Omani patients with type-2 diabetes to collect the data.Results:The findings indicated that DSM among the study subject is sub-optimal.Only 1%of them were regular on SMBG;9.5%of them exercise regularly;and 18%of them maintain healthy diet practices.No significant relationship between DSM and glycemic control(p>0.05)was found.DSM was found to be associated with age,gender,level of education,and duration of diabetes.Examining the differences between two regions in Oman(Muscat&Aldhakiliyah)indicated that participants from Muscat differ only in practicing SMBG.Conclusion:Results indicated that many Omani patients with type-2 diabetes do not perform DSM consistently.Practice implications:The findings of this study set the stage to develop teaching strategies that will improve DSM and subsequently improve diabetes management in patient with type-2 diabetes in Oman.

The Risk of Islet Cell and Insulin Autoantibodies and Their Predictive Strength as Markers of Type-1 Diabetes in a Cross-Section of Nigerian Population

Aim: We demonstrated the risk of developing islet autoantibodies-Insulin Autoanti-bodies (IAAs) and Islets cell Autoantibodies (ICAs)-in type-1 diabetic relatives and newly diagnosed type-1 patients compared to non-diabetic controls. We also aimed to determine the predictive strengths of both autoantibodies in the development of type-1 diabetes mellitus, and which of the two autoantibodies is a better predictive marker of type-1 diabetes mellitus among Nigerian adults. Methodology: A total number of four hundred and fifty five (455) subjects (211 (46%) males, and 244 (54%) females) aged between 35 - 76 years were recruited for the study. IAA and ICA levels were estimated using ELISA reagents from Biomerica Inc. Other parameters such as fasting blood sugar, urine glucose, and urine protein were assessed using standard biochemical techniques. Results: Relatives of type-1 diabetic patients and newly diagnosed type-1 diabetic patients were at greater risk (p < 0.05) of testing positive for more than one autoantibody (ICA and IAA) compared to non-diabetic controls. In addition, IAAs appeared to be better predictors or markers of type-1 diabetes mellitus compared to ICAs. Conclusion: The present study indicated a greater risk of autoim-mune destruction of the insulin producing beta cells of the pancrease of the type-1 relatives and newly diagnosed type-1 patients and suggests the need for periodic re-cruitment of individuals in the general population, siblings and relatives of type-1 diabetic patients for planned intervention trials. In addition, IAAs appeared to be better autoimmune markers of type-1 diabetes compared to ICAs.

8-isoPGF2α、Metrnl、LC3B-Ⅱ/LC3B-Ⅰ与T2MD患者血糖在目标范围内时间的相关性及预测糖尿病周围神经病变的价值

目的探讨8-异前列腺素F2α(8-isoPGF2α)、镍纹样蛋白(Metrnl)、微管相关蛋白3B-Ⅱ(LC3B-Ⅱ)/微管相关蛋白-Ⅰ(LC3B-Ⅰ)与2型糖尿病(T2MD)患者血糖在目标范围内时间(TIR)的相关性及对糖尿病周围神经病变(DPN)预测价值。方法选取2020年5月至2022年10月新乡医学院第一附属医院收治的187例T2DM患者进行前瞻性研究,根据是否合并DPN分为DPN组(n=48)和无DPN组(n=139)。比较两组患者及根据TIR四分位数分组的患者8-isoPGF2α、Metrnl、LC3B-Ⅱ/LC3B-Ⅰ水平,采用Pearson相关性分析8-isoPGF2α、Metrnl、LC3B-Ⅱ/LC3B-Ⅰ与TIR相关性,采用多因素Logistic回归分析DPN的相关影响因素;绘制受试者工作特征曲线(ROC)评价8-isoPGF2α、Metrnl、LC3B-Ⅱ预测DPN的价值。结果DPN组患者的TIR为(51.43±7.68)%,明显低于无DPN组的(56.94±8.12)%,差异有统计学意义(P<0.05);DPN组患者的8-isoPGF2α、Metrnl分别为(162.78±51.33)pg/mL、(259.18±74.42)pg/mL,明显高于无DPN组的(129.56±43.00)pg/mL、(208.37±65.61)pg/mL,LC3B-Ⅱ/LC3B-Ⅰ为0.89±0.27,明显低于无DPN组的1.15±0.31,差异均有统计学意义(P<0.05);根据TIR第25、50、75百分位数将全部患者分为Q1~Q4四组,8-isoPGF2α、Metrnl在Q4组最低,LC3B-Ⅱ/LC3B-Ⅰ在Q4组最高;8-isoPGF2α、Metrnl随着TIR降低逐渐升高,LC3B-Ⅱ/LC3B-Ⅰ随着TIR降低而降低,四组间比较差异均有统计学意义(P<0.05);Pearson相关性分析结果显示,8-isoPGF2α、Metrnl与TIR呈显著负相关(r=-0.786、-0.665,P<0.01),LC3B-Ⅱ/LC3B-Ⅰ与TIR呈显著正相关(r=0.711,P<0.01);多因素Logistic回归分析结果显示,TIR、LC3B-Ⅱ/LC3B-Ⅰ是DPN的独立相关保护因素(P<0.05),8-isoPGF2α、Metrnl是DPN的独立相关危险因素(P<0.05);ROC分析结果显示,单一指标中,Metrnl预测DPN的AUC最大(0.830),特异度最高(87.05%),8-isoPGF2α+Metrnl+LC3B-Ⅱ预测DPN的AUC为0.923(95%CI:0.875~0.957),大于Metrnl,预测敏感度为87.50%,特异度为85.61%(P<0.05)。结论8-isoPGF2α、Metrnl、LC3B-Ⅱ/LC3B-Ⅰ与T2MD患者TIR有关,均是患者并发DPN的预警因素。联合检测三者能为临床分层管理和早期识别DPN高风险人群提供参考。

Mimicking natural cholesterol assimilation to elevate the oral delivery of liraglutide for type Ⅱ diabetes therapy

Glucagon-like peptide-1 receptor agonists(GLP-1 RA)are a series of polypeptides broadly applied in the long-term treatment of typeⅡdiabetes.However,administration of GLP-RA is mainly through repetitive subcutaneous injection,which may seriously decrease the compliance and safety.Herein,a bio-inspired oral delivery system was designed to enhance the oral absorption of liraglutide(Lira),a kind of GLP-1 RA,by mimicking the natural cholesterol assimilation.25-hydroxycholesterol(25HC),a cholesterol derivative,was modified on the surfaced of Lira-loaded PLGA nanoparticles(Lira 25HC NPs)and functioned as a“top-down”actuator to facilitate unidirectional transcytosis across the intestinal epithelium.After oral delivery,Lira 25HC NPs displayed improved therapeutic effect as compared with oral free Lira on typeⅡdiabetes db/db mice,as evidenced by multiple relieved diabetic symptoms including the enhanced glucose tolerance,repressed weight growth,improved liver glucose metabolism,decreased fasting blood glucose,HbA 1c,serum lipid,and increasedβcells activity.Surprisingly,the fasting blood glucose,liver glucose metabolism,and HbA1c of oral Lira-loaded 25HC NPs were comparable to subcutaneous injection of free Lira.Further mechanisms revealed that 25HC ligand could mediate the nanoparticles to mimic natural cholesterol absorption by exerting high affinity towards apical Niemann-Pick C1 Like 1(NPC1L1)and then basolateral ATP binding cassette transporter A1(ABCA1)overexpressed on the opposite side of intestinal epithelium.This cholesterol assimilation-mimicking strategy achieve the unidirectional transport across the intestinal epithelium,thus improving the oral absorption of liraglutide.In general,this study established a cholesterol simulated platform and provide promising insight for the oral delivery of GLP-1 RA.

金匮肾气丸辅治Ⅱ-Ⅲ期糖尿病肾病疗效观察

目的:观察金匮肾气丸辅治Ⅱ-Ⅲ期糖尿病肾病的临床疗效。方法:74例按照随机数字表法分为对照组与研究组各37例,两组均用达格列净和贝那普利治疗,研究组加用金匮肾气丸。结果:研究组总有效率与估算肾小球滤过率(eGFR)水平高于对照组(P<0.05),中医证候积分、血肌酐(SCR)、血尿素氮(BUN)、24h尿总量蛋白(TUP)和尿微量白蛋白/尿肌酐(UMA/UCR)以及空腹血糖(FBG)水平均低于对照组(P<0.05)。结论:金匮肾气丸辅治Ⅱ-Ⅲ期糖尿病肾病可提高疗效。

The moderating effect of social cognitive factors on self-management activities and HbA1c in Thai adults with type-2 diabetes

Background: Diabetes mellitus (DM) has become a serious chronic disease.Self-management strategies help persons with DM make choices which will develop skills needed to reach their goal of blood glucose control and allow them to be successful in reaching goals.Objective: To examine the impact of self-management activities on HbA1c for persons with DM and to examine the impact of social support,self-efficacy and Buddhist values as moderators on the relationship between the self-management activities and HbA1c.Method: This study is a cross-sectional design.The sample included 401 Thai adults diagnosed with type 2 diabetes,aged 20-65 years old who had at least one HbA1c test in the last three months were recruited.Participants completed four questionnaires to measure self-management activities,as well as self-efficacy,Buddhist values and social support as moderating factors on self-management activities and HbA1 c,Results: The self-management activities were negatively associated (β =-2.05,p ≤ 0.001) with HbA1c.The Social support,self-efficacy and Buddhist values had a significant interaction effect between selfmanagement activities and HbA1c (β =-0.97,p ≤ 0.05,β =-0.18,p ≤ 0.05 and β =-2.76,p ≤ 0.001).Conclusion: The diabetes self-management activities were more strongly associated with HbA1c under conditions of high social support,self-efficacy and health beliefs with Buddhist values.Future interventions for T2DM self-management programs should incorporate mechanisms to measure and support these factors.

红外图像的一种Type-Ⅱ模糊增强算法

提出了一种基于Type-Ⅱ模糊集的红外图像增强算法,该算法首先根据像素的邻域相关性对图像进行预处理,然后以Ostu分割阈值为基础,构造了红外图像的Type-Ⅱ模糊特征平面;然后,采用不同的变换规则对图像进行模糊增强,并将结果进行融合;最后,通过Type reduction和去模糊化操作得到增强后的输出图像。对几幅典型的红外图像的增强实验表明,提出的方法能够有效地提高红外图像的对比度。

基于完备循环差集的大围长Type-Ⅱ QC-LDPC码的构造

针对当前type-Ⅱ准循环低密度奇偶校验(quasi-cyclic low-density parity-check,QC-LDPC)码的校验矩阵中存在权重为2的循环矩阵(weight-2circulant matrices,W2CM)导致Tanner图更容易产生短环,从而影响迭代译码收敛性的问题,基于完备循环差集(cyclic difference sets,CDS)提出了一种围长为8的type-ⅡQC-LDPC码的新颖构造方法。该方法构造的校验矩阵由权重为0的零矩阵、权重为1的循环置换矩阵和W2CM组成,保留了type-ⅡQC-LDPC码的具有更高最小距离上界的优点,改善了码的纠错性能;且Tanner图中无4、6环的出现,译码时具有较快的收敛速度。仿真结果表明:所构造的围长为8的type-ⅡQC-LDPC码在加性高斯白噪声信道下采用和积算法迭代译码时具有较好的纠错性能且无错误平层现象。

基于完备循环差集的type-Ⅱ QC-LDPC码的构造

针对当前type-Ⅱ的准循环低密度奇偶校验(quasi-cyclic low-density parity check,QC-LDPC)码中仅含有权重为2的循环置换矩阵而引入短环,导致迭代译码性能下降的问题,基于完备循环差集给出了近似双对角结构的type-ⅡQC-LDPC码的设计方法,该方法构造的奇偶校验矩阵由零矩阵,权重为1的循环单位阵和权重为2的循环矩阵组成,不但围长至少为8,而且还保留了type-ⅡQC-LDPC码具有更高最小距离上界的优点,从而使译码时可快速收敛。仿真结果表明:构造的type-ⅡQC-LDPC码在加性高斯白噪声(additive white Gauss noise,AWGN)信道下,采用和积(sum-product algorithm,SPA)译码时,码字无明显的错误平层且具有良好的纠错性能。

Type-Ⅱ型中红外发光二极管及激光器的进展情况

目前,中红外器件的应用已越来越广泛。为了更好地了解此类器件的结构和发展状况,本文结合国外在此方向上所取得的结果,对这类器件的结构设计做了比较详细的介绍。这些器件已能在218K温度下连续工作,其功率达到了500mW,78K时的阈值电流密度为31A/cm^2,特征温度也达到了103K。

Biomolecular basis of the role of diabetes mellitus in osteoporosis and bone fractures

Osteoporosis has become a serious health problem throughout the world which is associated with an increased risk of bone fractures and mortality among the people of middle to old ages.Diabetes is also a major health problem among the people of all age ranges and the sufferers due to this abnormality increasing day by day.The aim of this review is to summarize the possible mechanisms through which diabetes may induce osteoporosis.Diabetes mellitus generally exerts its effect on different parts of the body including bone cells specially the osteoblast and osteoclast,muscles,retina of the eyes,adipose tissue,endocrine system specially parathyroid hormone(PTH) and estrogen,cytokines,nervous system and digestive system.Diabetes negatively regulates osteoblast differentiation and function while positively regulates osteoclast differentiation and function through the regulation of different intermediate factors and thereby decreases bone formation while increases bone resorption.Some factors such as diabetic neuropathy,reactive oxygen species,Vitamin D,PTH have their effects on muscle cells.Diabetes decreases the muscle strength through regulating these factors in various ways and ultimately increases the risk of fall that may cause bone fractures.

Interface effect on superlattice quality and optical properties of InAs/GaSb type-Ⅱ superlattices grown by molecular beam epitaxy

We systematically investigate the influence of InSb interface(IF)engineering on the crystal quality and optical properties of strain-balanced InAs/GaSb type-Ⅱsuperlattices(T2SLs).The type-Ⅱsuperlattice structure is 120 periods InAs(8 ML)/GaSb(6 ML)with different thicknesses of InSb interface grown by molecular beam epitaxy(MBE).The highresolution x-ray diffraction(XRD)curves display sharp satellite peaks,and the narrow full width at half maximum(FWHM)of the 0th is only 30-39 arcsec.From high-resolution cross-sectional transmission electron microscopy(HRTEM)characterization,the InSb heterointerfaces and the clear spatial separation between the InAs and GaSb layers can be more intuitively distinguished.As the InSb interface thickness increases,the compressive strain increases,and the surface“bright spots”appear to be more apparent from the atomic force microscopy(AFM)results.Also,photoluminescence(PL)measurements verify that,with the increase in the strain,the bandgap of the superlattice narrows.By optimizing the InSb interface,a high-quality crystal with a well-defined surface and interface is obtained with a PL wavelength of 4.78μm,which can be used for mid-wave infrared(MWIR)detection.