Unveiling osteoprotective potential of biologically active naringenin in rats with dexamethasone-induced osteoporosis

Objective To investigate the protective effects of naringenin(NRG)against dexamethasone(DEX)-induced osteoporosis(OP)in rats.Methods Molecular docking of NRG was done with AutoDock Vina 1.2.0 software.Forty-eight female Wistar rats were randomly divided into six groups(n=8 each):normal control(NC),DEX(7 mg/kg,i.m.),NRG-low(NRG-L;25 mg/kg,i.g.),NRG-medium(NRG-M;50 mg/kg,i.g.),NRG-high(NRG-H;100 mg/kg,i.g.),and alendronate(ALN;0.25 mg/d,i.g.)groups.OP was induced by administering DEX once a week for five weeks in all groups except NC group.Begining in the third week after the initial DEX administration,the rats in NRG-L,NRG-M,NRG-H,and ALN groups received the corresponding treatments daily for three weeks,while NC and DEX groups received no additional treatment.Serum samples were collected at the end of the experiment for biochemical,bone turnover,antioxidant,lipid profile,and inflammatory cytokine analyses.Femur bones underwent physical parameter testing and histopathological examination.Results The molecular docking results illustrated that NRG docked with calcitonin(CT),lowdensity lipoprotein(LDL),bone morphogenetic protein(BMP),vascular endothelial growth factor(VEGF)receptor,forkhead transcription factors,and osteoprogenitor cells showed good binding energy.In rats administered with 25,50,and 100 mg/kg NRG,there was a significant enhancement in serum biochemical indices,characterized by a reduction in tartrate-resistant acid phosphatase(TRAP),parathyroid hormone(PTH),and an elevation in osteocalcin(OC)and CT levels(P<0.05,P<0.01,and P<0.001,respectively).Despite no significant changes in thickness,weight,and length(P>0.05),there was a marked increase in bone mineral density(BMD)(P<0.01,P<0.001,and P<0.001,respectively).Antioxidant enzyme markers showed significant upregulation,with higher glutathione,superoxide dismutase,and catalase,and a concurrent decrease in malondialdehyde(MDA)(P<0.05,P<0.01,and P<0.001,respectively).The lipid profile also improved significantly,with lower cholesterol(CH),triglycerides(TG),and low-density lipoprotein(LDL)levels,and an increase in high-density lipoprotein(HDL)level(P<0.05,P<0.01,and P<0.001,respectively).Inflammatory cytokine levels were reduced,as evidenced by decreases in tumor necrosis factor(TNF),interleukin(IL)-6,and IL-1β(P<0.05,P<0.01,and P<0.001,respectively).Furthermore,histological alterations revealed obvious improvements,and the body weight of rats treated with NRG showed an increase compared with DEX group.Conclusion These findings imply that NRG exhibited a protective effect against DEX-induced OP in rats as it promotes the bone formation process by increasing the number of bone turnover markers including OC and CT,and restoring of antioxidant status,lipid metabolism,and inflammatory markers.

Dexamethasone implant in naive versus refractory patients with diabetic macular edema:a Meta-analysis

AIM:To evaluate the efficacy and safety of the intravitreal dexamethasone implant in naive and refractory patients with diabetic macular edema(DME).METHODS:PubMed,Embase,Web of Science,and Medline databases were searched.The main outcomes were best-corrected visual acuity(BCVA)and central retinal thickness(CRT).The secondary outcomes included mean number of injections,intraoperative or postoperative complications including intraocular pressure(IOP)elevation and cataract.RESULTS:Ten comparative studies involving a total of 1000 DME eyes including 402 naive eyes and 598 refractory eyes were selected.The postoperative BCVA in the naive group was significantly better than in the refractory group[mean difference(MD)-0.11,95% confidence interval(CI)-0.17 to-0.05,P=0.0003;MD 8.69,95%CI 5.08 to 12.30,P<0.00001].Additionally,the naive group got greater improvement of BCVA change as well as more gains of BCVA letters than the refractory group[MD 7.71,95%CI 2.02 to 13.40,P=0.008;odds ratio(OR)2.99,95%CI 2.05 to 4.37,P<0.00001].The subgroup analysis revealed that the naive group had significantly higher BCVA gains of≥5,≥10,and≥15 letters compared to the refractory group(P=0.002,0.0001,0.003,respectively).No significant difference was detected between the two groups in either postoperative CRT(MD-22.36,95%CI-46.39 to 1.66,P=0.07)or the overall mean number of injections(MD-0.08,95%CI-0.38 to 0.22,P=0.61).Intraoperative and postoperative complications including the elevation of IOP(OR 0.47,95%CI 0.20 to 1.13,P=0.09)and cataract(OR 1.78,95%CI 0.97 to 3.24,P=0.06)showed no significant differences between the two groups during the follow-up time.CONCLUSION:Intravitreal dexamethasone implants for DME can improve anatomical and functional outcomes in both naive and refractory eyes and have a well-acceptable safety profile.Moreover,naive eyes maintain better visual outcomes than refractory eyes.It provides further evidence of better visual response when used for naive eyes as firstline therapy.

Dexamethasone implant for refractory macular edema secondary to diabetic retinopathy and retinal vein occlusion

AIM:To evaluate the efficacy,timing of retreatment and safety of dexamethasone(DEX)implant on macular edema(ME)secondary to diabetic retinopathy(DME)and retinal vein occlusion(RVO-ME)patients who were refractory to anti-vascular endothelial growth factor(VEGF)treatment.METHODS:This retrospective study included 37 eyes received at least one DEX implant treatment for DME or RVO-ME between January 1,2019,and January 1,2023.These refractory DME and RVO-ME cases received at least 5 anti-VEGF injections and failure to gain more than 5 letters or a significant reduction in central retinal thickness(CRT).The best corrected visual acuity(BCVA)and CRT were measured at baseline,and at 1,3,4 and 6mo post-DEX implant injection.Adverse events such as elevated intraocular pressure(IOP)and cataract were recorded.RESULTS:For RVO cases(n=22),there was a significant increase in BCVA from 0.27±0.19 to 0.35±0.20 at 6mo post-DEX injection(P<0.05)and CRT decreased from 472.1±90.6 to 240.5±39.0μm at 6mo(P<0.0001).DME cases(n=15)experienced an improvement in BCVA from 0.26±0.15 to 0.43±0.20 at 6mo post-DEX implant injection(P=0.0098),with CRT reducing from 445.7±55.7 to 271.7±34.1μm at 6mo(P<0.0001).Elevated IOP occurred in 45.9% of patients but was well-controlled with topical medications.No cases of cataract or other adverse events were reported.CONCLUSION:DEX implants effectively improve BCVA and reduce CRT in refractory DME and RVO-ME.Further research with larger cohorts and longer follow-up periods is needed to confirm these findings and assess long-term outcomes.

High-dose dexamethasone regulates microglial polarization via the GR/JAK1/STAT3 signaling pathway after traumatic brain injury

Although microglial polarization and neuroinflammation are crucial cellular responses after traumatic brain injury,the fundamental regulatory and functional mechanisms remain insufficiently understood.As potent anti-inflammato ry agents,the use of glucoco rticoids in traumatic brain injury is still controversial,and their regulatory effects on microglial polarization are not yet known.In the present study,we sought to determine whether exacerbation of traumatic brain injury caused by high-dose dexamethasone is related to its regulatory effects on microglial polarization and its mechanisms of action.In vitro cultured BV2 cells and primary microglia and a controlled cortical impact mouse model were used to investigate the effects of dexamethasone on microglial polarization.Lipopolysaccharide,dexamethasone,RU486(a glucocorticoid receptor antagonist),and ruxolitinib(a Janus kinase 1 antagonist)were administered.RNA-sequencing data obtained from a C57BL/6 mouse model of traumatic brain injury were used to identify potential targets of dexamethasone.The Morris water maze,quantitative reverse transcription-polymerase chain reaction,western blotting,immunofluorescence and confocal microscopy analysis,and TUNEL,Nissl,and Golgi staining were performed to investigate our hypothesis.High-throughput sequencing results showed that arginase 1,a marker of M2 microglia,was significantly downregulated in the dexamethasone group compared with the traumatic brain injury group at3 days post-traumatic brain injury.Thus dexamethasone inhibited M1 and M2 microglia,with a more pronounced inhibitory effect on M2microglia in vitro and in vivo.Glucocorticoid receptor plays an indispensable role in microglial polarization after dexamethasone treatment following traumatic brain injury.Additionally,glucocorticoid receptor activation increased the number of apoptotic cells and neuronal death,and also decreased the density of dendritic spines.A possible downstream receptor signaling mechanism is the GR/JAK1/STAT3 pathway.Overactivation of glucocorticoid receptor by high-dose dexamethasone reduced the expression of M2 microglia,which plays an antiinflammatory role.In contrast,inhibiting the activation of glucocorticoid receptor reduced the number of apoptotic glia and neurons and decreased the loss of dendritic spines after traumatic brain injury.Dexamethasone may exe rt its neurotoxic effects by inhibiting M2 microglia through the GR/JAK1/STAT3 signaling pathway.

Treatment Efficacy and Safety of Bortezomib Combined with Dexamethasone and Lenalidomide Chemotherapy Regimen for Multiple Myeloma

Objective:To analyze the effect of bortezomib combined with dexamethasone and lenalidomide in the treatment of multiple myeloma.Methods:60 cases of multiple myeloma patients admitted to our hospital from January 2022 to December 2023 were selected randomly,with 30 cases in each group.Bortezomib combined with dexamethasone was administered in the control group,and bortezomib combined with dexamethasone and lenalidomide was given to the observation group,and the treatment effect was analyzed.Results:After treatment,CD^(3+)and CD^(4+)of the observation group were higher than that of the control group,CD^(8+)was lower than that of the control group,and the total treatment efficiency was higher,which was statistically significant(P<0.05),and there was no difference in the total incidence of adverse reactions between the two groups(P>0.05).Conclusion:Bortezomib combined with dexamethasone and lenalidomide is effective in the treatment of multiple myeloma as it regulates the immune function and is safe,thus it can be promoted in clinical practice.

基于ADE优化的IPMSM全速域无传感器控制

为了实现内置式永磁同步电机(IPMSM)全速域的无传感器控制和切换速域的平滑过渡,提出了一种基于自适应差分进化(ADE)算法优化的复合控制方法。分别在零低速域、中高速域采用旋转高频电压注入法和滑模观测器法来对电机转速和转子位置进行估算,并在切换速域采用基于ADE算法的权重系数优化法来实现上述两种控制方法的平滑切换,从而实现IPMSM全速域无传感器控制。仿真结果表明:提出的复合控制方法能够实现电机全速域的无感控制和切换速域的平滑过渡,且具有良好的稳定性。

补肾活血汤辅助VAD治疗多发性骨髓瘤肾损害临床疗效及对骨代谢、肾功能的影响

目的 探讨补肾活血汤辅助VAD治疗(长春新碱+阿霉素+地塞米松)多发性骨髓瘤肾损害的临床疗效,同时动态观察该治疗方案对骨代谢、肾功能的影响。方法 选择2019年1月—2021年1月88例确诊为多发性骨髓瘤且伴有肾损害的患者作为研究对象,采用随机数字法平均分为观察组与对照组两组:对照组给予VAD治疗方案,观察组在对照组基础上辅以补肾活血汤治疗。比较两组治疗4个疗程后临床疗效差异,与治疗前、治疗2个疗程、4个疗程后比较骨代谢指标、肾功能指标等差异。结果 观察组总有效率90.9%明显高于对照组75.0%,差异比较有统计学意义(P<0.05)。随着治疗时间延长,两组患者主症、次症及总积分均逐渐降低(P<0.05);治疗2疗程及4疗程后观察组主症、次症及总积分均低于对照组(P<0.05)。随着治疗时间延长,两组患者RANKL逐渐降低(P<0.05),ALP、OCN逐渐升高(P<0.05);治疗2疗程及4疗程后观察组RANKL均低于对照组(P<0.05),而ALP、OCN均高于对照组(P<0.05)。随着治疗时间延长,两组患者Scr、β2-MG、NGAL、KIM-1、Cys-C、尿mAlb逐渐降低(P<0.05);治疗2疗程及4疗程后观察组Scr、β2-MG、NGAL、KIM-1、Cys-C、尿mAlb均低于对照组(P<0.05)。结论 补肾活血汤辅助VAD治疗多发性骨髓瘤肾损害的临床疗效更显著,可以更好地改善症状,更好调节骨代谢,更有效地逆转肾功能损害。

儿童维生素AD滴剂,这样吃才对

众所周知,维生素A、D对孩子的生长发育至关重要。而补充维生素A、D,最好选择专门的维生素AD制剂,比如维生素AD滴剂。但许多家长对其又不甚了解,有诸多疑问。以下,笔者将一一进行解答。

ADS-B信号在对流层大气波导中的传播性能

对流层大气环境存在特殊大气结构“大气波导”,可形成电波超视距传播或产生雷达盲区等。目前,通过雷达、GNSS信号等可以对大气波导进行一定程度的反演探测,但均存在一定的不足。ADS-B信号具有应用范围广、信号密度大、实时性高等特点,为此提出利用ADS-B信号受到不同大气环境影响后能量损耗不同的特点对ADS-B信号与对流层大气环境关联性进行分析研究。以武汉地区ADS-B信号数据为例,基于抛物方程传播理论对路径损耗进行仿真分析,并进行了实验验证。结果表明:ADS-B接收信号与仿真结果存在线性相关性并给出线性表述,为后续利用ADS-B信号反演大气波导提供参考依据。

星基ADS-B系统空天链路的建模与仿真

星基广播式自动相关监视(ADS-B,automatic dependent surveillance-broadcast)系统是一种新型的航空器监视技术,在未来空中交通管理系统中具有广阔的应用前景。为了深入研究星基ADS-B系统中航空器到卫星的空天链路通信性能,将专业软件Matlab和STK(system tool kit)有效联合,构建符合国际标准的星基ADS-B空天链路完整模型;通过离散事件动态交互模拟ADS-B消息的发送与接收全过程,最后统计得出体现星基ADS-B空天链路通信性能的消息识别概率(POI,possibility of identify)、消息检测概率(POD,possibility of detective)、信号接收功率、信号冲突概率、卫星覆盖范围等指标。仿真结果表明,随着区域内航空器数量上升,POI、POD下降,消息冲突概率上升。

Observation of the Curative Effect of the Dexamethasone Vitreous Cavity Implant for the Treatment of Irvine-Gass Syndrome

Objective To investigate the clinical efficacy of dexamethasone vitreous cavity implants(Ozurdex)for the treatment of macular edema(Irvine-Gass Syndrome)after cataract surgery.Method Eight patients(eight eyes)with Irvine-Gass syndrome were enrolled for vitreous injections with Ozurdex.The patients included six men(six eyes)and two women(two eyes)with a mean age of 67.12±11.92 years.Changes in the patients best-corrected visual acuity(BCVA),central macular thickness(CMT),and intraocular pressure were compared before and after treatment.Result The mean visual acuity BCVA of the patients was 0.81±0.26 before implantation,which improved to 0.20±0.12,0.13±0.09,and 0.15±0.13 at 2 weeks,1 month,and 3 months after implantation,respectively(P<0.001).The patient’s mean CMT before implantation was 703.00±148.88μm,and it reduced to 258.87±37.40μm,236.25±28.74μm,and 278.00±76.82μm at 2 weeks,1 month,and 3 months after implantation,respectively(P<0.001).Conclusion The dexamethasone vitreous cavity implant(Ozurdex)is a safe and effective treatment,which can effectively improve patient’s visual acuity and reduce macular edema associated with cataract surgery.

基于迁移学习-元学习的ADS-B攻击分类研究

准确分类通航领域ADS-B攻击类型,采取预防攻击措施,对保障通航运行安全性具有重要意义。针对通航领域ADS-B攻击数据样本少,提出一种基于迁移学习-元学习的ADS-B攻击分类模型。该模型将迁移学习与深度卷积自编码器相结合,建立ADS-B攻击特征提取模型,提取数据样本的攻击有效特征表示,并运用元学习策略在特征空间中实现ADS-B攻击准确分类。实例研究表明,基于迁移学习-元学习的攻击分类模型可有效分类小样本ADS-B攻击,且正确率在95%以上。

基于多时间特征融合网络的ADS-B实采信号分离

不同于以往单天线广播式自动相关监视(Automatic Dependent Surveillance-Broadcast,ADS-B)信号分离中利用仿真的ADS-B信号制作数据集,将单天线接收的真实飞机发射的ADS-B原始信号通过调整信号起始时间以及功率并人为增加噪声来制作数据集。为了提高信号分离的时域波形精度,提出一种多分辨率多时间特征融合重采样(Multi-Temporal fusion Resampling of Multi-Resolution Features,MTRM-RF)网络,通过卷积将信号转化成不同采样率的信号并分别使用多层堆叠逐渐膨胀的一维卷积提取不同时间间隔的特征,以获得更多的时间信息。对多种基于深度学习的语音分离网络进行比较发现,MTRM-RF网络能够有效地融合ADS-B信号的不同采样率、不同时间间隔采样点的特征进行训练。并且随着训练集数据量的增加,分离信号的平均解码正确率达到88.39%,证明该网络可有效分离单天线实采的ADS-B交织信号。

Effects of chronic dexamethasone administration on hyperglycemia and insulin release in goats

Background: Dexamethasone(Dex), a synthetic glucocorticoid, is among the most commonly used drugs worldwide in animals and humans as an anti-inflammatory and immunosuppressive agent. GC has profound effects on plasma glucose level and other metabolic conditions. However, the effect of prolonged use of Dex on glucose metabolism in ruminants is still unclear.Results: Ten goats were randomly assigned to two groups: the control goats were injected with saline, and the Dex-treated goats were intramuscularly injected daily for 21 d with 0.2 mg/kg Dex. The results showed that plasma glucose and insulin concentrations were significantly increased after Dex administration(P < 0.05). Additionally, the content of hepatic glycogen was also markedly increased in Dex-treated goats(P < 0.01), while the content of glycogen in dorsal longissimus was unchanged by Dex(P > 0.05). The expression of several key genes, involved in blood glucose regulation, was detected by real-time PCR in the small intestine, skeletal muscle and liver. The expression of glucose transporter type 2(GLUT2), sodium-glucose transporter 1(SGLT1) and sodium-potassium ATPase(Na-K/ATPase) in the small intestine were generally increased by Dex, and GLUT2 m RNA expression was significantly up-regulated(P < 0.05). In liver, the expression of genes involved in gluconeogenesis including glucose-6-phosphatase catalytic subunit(G6 PC), cytosolic form of phosphoenolpyruvate carboxykinase(PCK1) and pyruvate carboxylase(PC), were significantly down-regulated by Dex. However, the protein expression levels of PCK1 & PCK2 were significantly increased by Dex, suggesting a post-transcriptional regulation. In dorsal longissimus, the m RNA expression of genes associated with gluconeogenesis and the insulin signaling pathway were generally upregulated by Dex, but the m RNA expression of two markers of muscle atrophy, namely F-box protein 32(FBXO32/Atrogin1) and muscle RING-finger protein 1(Mu RF1), was not altered by Dex.Conclusions: Taken together, these results indicate that chronic administration of a low dosage of Dex induces hyperglycemia mainly through gluconeogenesis activation in the goat liver.

Dexamethasone potentiates the insulin-induced Srebp-1c expression in primary rat hepatocytes

The impacts of dexamethasone(Dex)and thyroid hormone T3 on the insulin-stimulated Srebp-1c expression were studied in primary rat hepatocytes. Primary hepatocytes from Sprague-Dawley rats were isolated, cultured and treated with insulin in the presence or absence of the indicated reagents over time. The mRNA levels of indicated genes were determined using real-time PCR. Insulin treatment induced the Srebp-1c expression and suppressed the Pck1 expression in a time-dependent manner. Dex treatment alone reduced the Srebp-1c expression, whereas potentiated the insulin-induced its expression, which reached to a level that was higher than the insulin alone group. On the other hand, insulin treatment completely suppressed the Dex-induced Pck1 expression in the same cells. T3 treatment did not affect the expressions of Srebp-1c and Pck1 alone or in the presence of absence of insulin or Dex. Interestingly, insulin treatment induced the Rxrg m RNA expression level in the absence or presence of T0901317, a specific agonist for the liver X receptor. Dex and insulin mutually affect each other's ability to regulate the expression levels of hepatic genes involved in glucose and fatty acid metabolism. Insulin induced Rxrg expression in primary hepatocytes, which may contribute to the induction of Srebp-1c expression in the same cells.

Combination of cataract surgery with intravitreal injection of dexamethasone intravitreal implant(Ozurdex)for uveitis-induced cataract

AIM:To evaluate the long-term results of patients with chronic uveitis-induced cataract by phacoemulsification with IOL implantation and intravitreal injection of dexamethasone(DEX)intravitreal implant(Ozurdex).METHODS:The study included 32 eyes of 26 patients treated with DEX implant due to chronic uveitis-induced cataract and followed up for at least a year.Best-corrected visual acuity(BCVA),intraocular pressure(IOP),anterior chamber reaction,central macular thickness(CMT),intraoperative and postoperative complications and uveitis recurrence were analyzed retrospectively.RESULTS:A successful surgery was performed in all patients.The average follow-up period was 12mo.The female/male ratio was 13/13.Mean age was 45.65±3.83y(range 26 to 65y).Etiologically,rheumatic arthritis occurred in 6 patients(18.75%),ankylosing spondylitis in 4(12.50%),HLA-B27 associated uveitis in 3(9.38%),Vogt-KoyanagiHarada-associated uveitis in 4(12.50%),Behcet’s disease in 2(6.25%),and 7(21.88%)suffered from unknown diseases.All 32 eyes had varying degrees of improvement at 12mo after surgery,with 2 eyes showing BCVA of 0.1 or below(6.25%),6 having 0.1-0.5(18.75%),18 of 0.5-1.0(56.25%),and 6 of 1.0 or above(18.75%).No cases with increased IOP were observed.The values of mean CMT was increased at day 1,decreased at 1,3mo after surgery and increased at 6,12mo after surgery.No severe uveitis reactions,such as fibrinous exudates in the anterior chamber and exudative membrane formation on the anterior surface of the IOL,were observed after surgery.CONCLUSION:The present studies show that intravitreal injection of Ozudex during cataract operation can provide a new option for the clinical treatment of uveitis-induced cataract.

基于AD与TRIZ的加工中心主轴松拉刀机构优化设计

数控加工中心在加工过程中常出现主轴松刀力不足或无法松刀的现象。针对此问题,通过TRIZ系统组件分析明确现有松拉刀机构各组件间作用关系,利用因果链分析得出影响松刀的根本原因,最终应用TRIZ理论中的物场模型分析方法和AD独立性原理提出优化设计方案。根据新方案计算出实际工况下的主轴松刀力和螺杆强度,并对松刀杆进行建模和仿真。结果表明:最大位移量为6.995μm,最大应力为45.24 MPa,符合结构设计要求。最后,经过现场实物测试,当液压力为5 MPa时,松刀行程、松刀力以及打刀量均符合生产要求,验证了优化设计方案的合理性。

白菜型冬油菜BrADS2基因的克隆、表达分析与亚细胞定位

【目的】探究白菜型冬油菜(Brassica rapa L.)脂肪酸去饱和酶ADS2(Δ9 fatty acid desaturase)基因与抗寒性的关系。【方法】基于前期转录组结果,采用一步定向克隆法得到BrADS2基因;构建GFP融合表达载体,通过注射法在烟草下表皮细胞进行瞬时转化,同时采用农杆菌侵染法侵染‘中双11号’;利用qRT-PCR技术,检测抗寒性不同的白菜型冬油菜品种叶片中ADS2基因的表达模式,并对低温下冬油菜的形态变化和抗氧化酶活性、电导率含量进行分析。【结果】白菜型冬油菜BrADS2基因可编码307个氨基酸,该基因编码的蛋白具有亲水性特性;qRT-PCR结果显示,BrADS2基因的表达量呈先升后降的单峰型变化,且在-4℃时表达量达到峰值;亚细胞定位结果显示BrADS2蛋白在细胞质和细胞膜上表达;低温处理下3个品种叶片的相对电导率、抗氧化物酶活性均显著上升,强抗寒品种抗氧化酶活性高于弱抗寒品种,电导率却相反;农杆菌介导侵染‘中双11号’下胚轴后获得15株转基因阳性苗,且转基因油菜阳性植株叶中的BrADS2基因表达量均显著高于野生型。【结论】推测BrADS2基因在白菜型冬油菜膜脂不饱和调节中起重要作用,揭示了ADS2基因与冬油菜抗低温胁迫的关系。

基于改进型多斜Ⅲ技术的7位半AD转换器设计

高精度测试仪器在环境试验中扮演着重要角色,而积分型AD转换器被广泛的应用在高精度测试仪器中。针对传统型积分型AD转换器转换速率较低的问题,提出了一种提高转换速率的改进型多斜ⅢAD转换器,详细的介绍了其原理和设计思路。该转换器以单片机与CPLD一同控制积分型ADC,在积分末尾利用单片机片内ADC测量积分器的残留电压,以达到提高转换速率的目的。经理论分析该AD转换器比传统型转换速率快836倍,分辨率可达到31位,在±10V直流电压测量中可实现7位半分辨率。

The therapeutic mechanism of dexamethasone in lung injury induced by hydrogen sulfide

The lung is one of the primary target organs of hydrogen sulfide(H2S),as exposure to H2S can cause acute lung injury(ALI)and pulmonary edema.Dexamethasone(Dex)exerts a protective effect on ALI caused by exposure to toxic gases and is commonly used in the clinic;however,the underlying mechanisms remain elusive,and the dose is unclear.Methods:In vivo experiments:divided C57BL6 mice into 6 groups at random,12 in each group.The mice were exposed to H2S for 3 h and 5 or 50 mg/kg Dex pretreated before exposure,sacrificed 12 h later.The morphological changes of HE staining and the ultrastructural changes of lungs under transmission electron microscopy were evaluated.The wet/dry ratio of lung tissue was measured.Bronchial alveolar lavage fluid(BALF)protein content and lung permeability index were detected.The expression of AQP5 protein was measured by immunohistochemistry and Western Blot(WB).In vitro experiments:divided human lung adenocarcinoma cell line A549 into 4 groups.1μmol/L dexamethasone was added to pre-incubation.The WB analyzed the protein of p-ERK1/2,p-JNK,and p-p38 in MAPK pathway after 1 h of NaHS exposure;six hours after NaHS exposure,the AQP5 protein was measured by WB.Results:Dex treatment could significantly attenuate the H2S-induced destruction to the alveolar wall,increase the wet-to-dry weight ratio and decrease pulmonary permeability index,with high-dose dexamethasone seemingly functioning better.Additionally,our previous studies showed that aquaporin 5(AQP 5),a critical protein that regulates water flux,decreased both in a mouse and cell model following the exposure to H2S.This study indicates that tThe decrease in AQP 5 can be alleviated by Dex treatment.Additionally,the mitogen activated protein kinase(MAPK)pathway may be involved in the protective effects of Dex in ALI caused by exposure to H2S since H2Sinduced MAPK activation could be inhibited by Dex.Conclusion:The present results indicate that AQP 5 may be considered a therapeutic target for Dex in H2S or other hazardous gases-induced ALI.