Medical management of urolithiasis: Great efforts and limited progress

Objective:To provide a comprehensive review on the existing literature on medical management of urolithiasis.Methods:A thorough literature review was performed using Medline,PubMed/PMC,Embase,and the Cochrane Database of Systematic Reviews up to December 2022 to identify publications on the medical management of urolithiasis.Studies that assessed dietary and pharmacologic management of urolithiasis were reviewed;studies on medical expulsive therapy were not included in this review.Results:Medical management of urolithiasis ranges from the prophylactic management of kidney stone disease to dissolution therapies.While most treatment concepts have been long established,large randomized controlled trials are scarce.Dietary modification and increased fluid intake remain cornerstones in the conservative management of urolithiasis.A major limitation for medical management of urolithiasis is poor patient compliance.Conclusion:Medical management of urolithiasis is more important in patients with recurrent urolithiasis and patients with metabolic abnormalities putting them at higher risk of developing stones.Although medical management can be effective in limiting stone recurrence,medical interventions often fail due to poor compliance.

Monogenic features of urolithiasis: A comprehensive review

Objective: Urolithiasis formation has been attributed to environmental and dietary factors. However, evidence is accumulating that genetic background can contribute to urolithiasis formation. Advancements in the identification of monogenic causes using high-throughput sequencing technologies have shown that urolithiasis has a strong heritable component.Methods: This review describes monogenic factors implicated in a genetic predisposition to urolithiasis. Peer-reviewed journals were evaluated by a PubMed search until July 2023 to summarize disorders associated with monogenic traits, and discuss clinical implications of identification of patients genetically susceptible to urolithiasis formation.Results: Given that more than 80% of urolithiases cases are associated with calcium accumulation, studies have focused mainly on monogenetic contributors to hypercalciuric urolithiases, leading to the identification of receptors, channels, and transporters involved in the regulation of calcium renal tubular reabsorption. Nevertheless, available candidate genes and linkage methods have a low resolution for evaluation of the effects of genetic components versus those of environmental, dietary, and hormonal factors, and genotypes remain undetermined in the majority of urolithiasis formers.Conclusion: The pathophysiology underlying urolithiasis formation is complex and multifactorial, but evidence strongly suggests the existence of numerous monogenic causes of urolithiasis in humans.

Percutaneous nephrostomy versus ureteral stent in hydronephrosis secondary to obstructive urolithiasis:A systematic review and meta-analysis

Objective: To assess if there is a preferable intervention between retrograde ureteral stent (RUS) and percutaneous nephrostomy (PCN) tube, in cases of upper urinary tract stone obstruction with complications requiring urgent drainage, by evaluating outcomes regarding urinary symptoms, quality of life (QoL), spontaneous stone passage, and length of hospital stays, since there is no literature stating the superiority of one modality over the other.Methods: We searched MEDLINE and other sources for relevant articles in June 2019 without any date restrictions or filters applied. The selection was done first by the title and abstract screening and then by full-text assessment for eligibility. Only randomized controlled trials or cohort studies in patients with hydronephrosis secondary to obstructive urolithiasis that presented comparative data between PCN and RUS placement concerning at least one of the defined outcome measures were included. Lastly, MEDLINE database and PubMed platform were screened again using the same terms, from June 2019 until November 2022.Results: Of 556 initial articles, seven were included in this review. Most works were considered of moderate-to-high quality. Three studies regarding QoL showed a tendency against stenting, even though only one demonstrated statistically significant negative impact on overall health state. Two works reported significantly more post-intervention urinary symptoms in stenting patients. One article found that PCN is a significant predictor of spontaneous stone passage, when adjusted for stone size and location. Findings on length of hospital stays were not consistent among articles.Conclusion: PCN appears to be the intervention better tolerated, with less impact on the patient’s perceived QoL and less post-operative urinary symptoms, in comparison with RUS. Nevertheless, further studies with larger samples and a randomized controlled design are suggested.

通信限制下多DG接入配网的新型电流差动保护

差动保护是解决分布式电源(distributed generation, DG)接入下配电网保护难题的有效手段,然而配网现有通信建设水平很大程度上制约了差动保护的构建。首先,融合电流相位与相量差动保护思想,同时将电流相位信息进行变换,实现通信信息降容。应用递推最小二乘法实现短路电流相位参数的快速估计,提出了短路电流相位修正策略,以应对CT饱和与直流分量对保护的干扰。最后,提出适用于含多DG配网的新型电流差动保护构建原则与保护判据。基于PSACD/EMTDC平台搭建仿真模型,验证了所提出的电流相位参数预测方法的精度与新型差动保护的性能。算例结果表明:所提电流相位参数预测方法速度快、精度高,具有良好的抗CT饱和能力;所提新型差动保护原理具有良好的性能。

棉花黄萎病生防菌筛选鉴定及根瘤菌DG3-1对棉花生长的影响

本研究旨在发掘南疆棉花内生菌种质资源来防治棉花黄萎病,探究根瘤菌对棉花生长的影响。采用常规组织分离法分离棉花不同组织内生细菌;平板对峙法筛选拮抗棉花黄萎病菌的内生菌,并对其进行分子鉴定;通过盆栽试验研究根瘤菌对棉花生长的影响。结果显示,棉花不同组织内生细菌的数量具有一定差异,根部最多,其次是叶和茎;在分离获得的31株内生菌中,有11株对棉花黄萎病菌具有拮抗活性,抑菌率在35.99%~68.28%之间,经鉴定,9株为芽孢杆菌,2株为根瘤菌,其中,根瘤菌DG3-1对棉花黄萎病菌的抑制率为(56.63±1.82)%;盆栽试验结果表明,菌株DG3-1处理后棉株的地上鲜重、地上干重、地下鲜重、地下干重、叶绿素含量分别比对照增加2.12、2.09、1.05、0.75、1.75倍。菌株DG3-1对棉花黄萎病菌有较好的抑制作用,并且对棉花的生长有一定的促生作用,是防治棉花黄萎病的潜力菌株,可为微生物菌剂的研发提供菌种资源。

基于DGS的切比雪夫低通滤波器设计

为了抑制微波传输系统中的高次谐波以及杂散信号,采用DGS(缺陷地结构)来设计低通滤波器。通过在经典的五阶切比雪夫低通滤波器的接地面上蚀刻多个哑铃型DGS结构,获得了较好的通带和阻带性能。仿真及测试结果显示,采用DGS结构设计的低通滤波器,其通带截止频率为1.4 GHz,0~1.4 GHz通带内回波损耗值优于-20 dB且插入损耗值小于0.5 dB,阻带范围为2~10 GHz。经实物加工测试分析表明,实测结果与仿真结果吻合较好。设计的DGS结构低通滤波器在无线通信系统中具有一定的应用前景。

基于DGS的紧凑型低通滤波器

文中提出一种基于缺陷地结构的新型低通滤波器。其由位于微带结构顶部的加宽微带线、位于接地层中的经典哑铃型缺陷地结构(DGS)和蛇形缝隙缺陷地结构(DGS)组成,结构设计紧凑,容易调整。文中选用0.01 dB等波纹的切比雪夫型低通滤波器,分别采用哑铃型DGS、蛇形缝隙DGS替换LPF原型电路中的电感,加宽微带线替换并联电容,同时将加宽微带线产生的寄生电感考虑进去。哑铃型DGS产生的高频衰减点加宽阻带,蛇形缝隙DGS提供的低频衰减点使得通带到阻带陡峭过渡。实验结果表明,所设计的截止频率为2.54 GHz的低通滤波器具有明显的截止频率响应,通带内插损均在0.9dB以下,阻带抑制均在21dB以下。经实物加工测试验证,所设计的低通滤波器实际结果与仿真结果基本一致,具有可行性。

基于高阶DG方法的非定常流场声辐射特性数值模拟研究

随着航空噪声越来越受到关注,计算声传播的算法成为研究热点。高阶间断伽辽金(Discontinuous Galerkin,DG)方法具有高精度、对网格质量要求低、适合自适应和并行计算等优点,可以以较高的效率对声场进行计算。文章运用高阶DG方法对线性化欧拉方程(Linearized Euler Equations,LEE)进行空间离散,并且基于离散后的线性化欧拉方程对带有背景流场的NACA0012翼型和30P30N多段翼型的声场进行数值计算。采用有限体积法计算得出流场信息后,通过插值将流场数据导入声场网格,并运用高阶DG方法进行声场计算。计算结果与参考文献中FW-H(Ffowcs Williams-Hawkings)算法对比一致性较好,验证了高阶DG算法的可行性。

The Deleterious Effect of Inappropriate Calcium and Vitamin D Supplementation during Pregnancy in Women Predisposed to Calcium Oxalate Urolithiasis

Background: Gestational formation of new urolithiasis is rare yet the impact of inappropriate gestational calcium and vitamin D supplementation (Ca/DS) is underestimated. Patients and Methods: we retrospectively evaluated 75 pregnant women with history of UL, yet were stable for >2 years on dietary restrictions, for new UL after Ca/DS. Results: During the past 5 years 21 (48%) of those who had received Ca/DS had developed UL and all had high Vitamin D with hypercalcemia while the remaining 31 patients, without Ca/DS, did not have UL and maintained normal vitamin D urinary calcium without need for supplementation. Overt UL was evident by 30th weeks of gestations and most were diagnosed by ultrasonography and managed by medical expulsive therapy. Conclusion: in patients with history of UL, prudent use of Ca/DS is indicated to avoid new UL.

基于多Agent的含DG智能配电网差动保护自愈方法

含DG智能配电网中的潮流方向随分布式发电的变化而变化,导致配电网故障自愈的效果难以保障,因此,提出基于多Agent的含DG智能配电网差动保护自愈方法。通过构建基于多Agent的MAS体系结构,将其应用于含DG智能配电网差动保护和自愈的控制,在MAS体系结构的数据处理层完成差动保护,并在MAS体系结构的协调控制层实现故障自愈。结果表明,该设计方法不仅可以恢复配电网故障区域的电力,而且在操作次数、线损及功率因数方面可达到较理想的效果。

含高间歇性DG的配电网储能优化配置方法研究

高间歇性的分布式电源(DG)具有较大的随机性,并网发电后会对配电网运行的稳定性产生较大影响。为了保证配电网运行的电能质量和消纳能力,研究含高间歇性DG的配电网储能优化配置方法。首先,估算DG最大准入容量,分析配电网的消纳能力;接着,选取负荷控制目标,消除储能系统中存在的负荷毛刺。然后,基于需求侧响应协调规划配电网储能,以控制储能系统的发电和用电平衡。最后,建立含高间歇性DG的配电网储能优化配置模型,使电压趋近或保持在优化区间内。经试验论证分析,所提方法可以使负荷曲线的波动范围缩小到250~350 kW,对负荷具有更好的控制能力。该方法能够有效地解决电压越线的问题,具有较好的电压调节效果。

考虑DG无功调节和不确定性的配电网新能源消纳容量评估

为充分考虑分布式电源不确定性和控制多样性对配电网运行的影响,提出了一种考虑分布式电源无功调节和不确定性配电网新能源消纳容量的评估方法。首先分析了分布式电源对配电网电压分布的影响、分布式电源无功调节能力以及分布式电源出力的不确定模型;其次,以最大化新能源消纳容量和最小网损为优化目标,以计及分布式电源无功调节和不确定性的有功-无功作为重要约束,建立配电网新能源消纳容量评估模型;然后,以分布式电源和无功补偿装置的出力为优化变量,通过快速非支配排序遗传算法进行求解,实现了新能源消纳容量的准确评估;最后通过应用实例进行验证。结果表明,所提评估方法实现了配电网新能源消纳容量的可靠评估。

Partitioning Calculation Method of Short-Circuit Current for High Proportion DG Access to Distribution Network

Aiming at the problemthat the traditional short-circuit current calculationmethod is not applicable to Distributed Generation(DG)accessing the distribution network,the paper proposes a short-circuit current partitioning calculation method considering the degree of voltage drop at the grid-connected point of DG.Firstly,the output characteristics of DG in the process of low voltage ride through are analyzed,and the equivalent output model of DG in the fault state is obtained.Secondly,by studying the network voltage distribution law after fault in distribution networks under different DG penetration rates,the degree of voltage drop at the grid-connected point of DG is used as a partition index to partition the distribution network.Then,iterative computation is performed within each partition,and data are transferred between partitions through split nodes to realize the fast partition calculation of short-circuit current for high proportion DG access to distribution network,which solves the problems of long iteration time and large calculation error of traditional short-circuit current.Finally,a 62-node real distribution network model containing a high proportion of DG access is constructed onMATLAB/Simulink,and the simulation verifies the effectiveness of the short-circuit current partitioning calculation method proposed in the paper,and its calculation speed is improved by 48.35%compared with the global iteration method.

DG大坝安全在线监控系统建设探析和应用

通过对DG大坝安全在线监控系统建设的研究,解决了传统的安全监测、自动化系统等已不能完全满足当前大坝安全管理需求的问题,为大坝安全状况在线分析、诊断、评判和预警提供决策支持手段,也为水利工程领域的安全监控研究提供了新的视角和方法,该研究可在行业内推广使用。

含DG的配网系统中性点接地方式设计研究

电力系统中性点接地方式是一个重要的综合性问题,对于电网正常运行具有重要意义。在当前的技术背景下,配网系统中性点接地方式主要包括大电流接地、小电流接地两种,并不存在统一的标准,不同接地方式适用于不同工作需求。文章通过对相关文献进行查阅,以含分布式电源(Distributed Generation,DG)的配网系统中性点接地为研究对象,设计含DG的配网系统中性点接地方式。为证实研究的有效性,结合仿真软件进行中性点接地方案仿真建模。最终发现,文章研究内容可以在架空线路、电缆线路2个场景中发挥出较为优越的技术效果,具有一定的实际应用价值。

基于DGS的3dB耦合线耦合器设计

本文提出了一种基于缺陷地结构的3dB高方向性耦合线耦合器的设计方法,该耦合器由两组耦合线耦合器组成。在电磁仿真软件Ansoft HFSS中对所提出的耦合线耦合器进行仿真分析,结果表明在中心频率2.5GHz处,回波损耗和方向性约为29dB,耦合度达到3.02dB,在2.28~2.84GHz的频率范围内耦合度的波动小于0.5dB,在2~3GHz频带内回波损耗、隔离度和方向性均优于20dB,耦合端与直通端相位差约为90o,具有良好相位正交性和宽带性能。

DGS-AT1M型海洋重力仪静态观测结果分析与评估

海洋重力仪的性能直接决定测量数据的质量,而海洋重力仪稳定性则是反映仪器性能的关键性指标。本文结合DGS-AT1M型海洋重力仪静态试验,分析了静态试验过程中影响观测结果的主要因素,研讨了海洋重力仪静态试验稳定性评估方法及流程,对该型海洋重力仪稳定性进行了分析与评估。首先,计算了理论固体潮重力值变化,改正了固体潮对静态观测结果的影响;然后,对单日观测数据以及整体数据进行分析;最后,根据稳定性评估流程,利用固体潮改正后的剩余观测值计算了仪器的零漂率、月漂以及准确度。计算表明,该型重力仪试验月漂值为-1.020 mGal,零漂线性良好且漂移率为-0.034 mGal/day,设备的测量准确度为0.085 mGal,符合重力测量的规范要求,可用于高精度海洋重力测量。

DG水电站导流洞封堵快速施工技术总结

导流洞封堵施工作为保证水库大坝结构及水库下闸正常蓄水并有效发电的核心步骤,工作进度及施工质量对水库正常蓄水发电和后期可靠运行具有重要意义。文章以西藏DG水电站为例,详细阐述了导流洞封堵快速施工技术的应用与实践,旨在为同类工程项目提供理论依据及实践参考。

分层模型与改进IA的含DG配电网故障定位研究

常规的含分布式发电(DG)装置的配电网故障定位方法忽略了配电网馈线节点数量的影响,导致定位结果精度不高。因此,将分层模型与改进免疫算法(IA)相结合,设计了分层模型与改进IA的含DG配电网故障定位方法。首先,构建三层含DG配电网故障分层模型,并分析单节点故障信息。然后,通过改进基础IA的抗体间相似度,优化算法的期望繁殖度。最后,基于改进后的IA优化分层模型的节点搜索路径,建立世界坐标系并融合DG开关状态得到最终的故障定位信息。试验结果表明:应用该方法定位的故障节点距离与真实的故障节点距离最大差值仅为0.013 km。该方法表现出的适应度值曲线与最优适应度值曲线高度接近,定位精度较高,能够满足含DG配电网故障运维工作的现实需求。

基于变异系数和支持向量机的含DG台区线损智能诊断研究

分布式电源的接入改变了台区潮流,增加了台区线路高损概率。为找出引起台区线路高损成因,提出一种基于变异系数法和支持向量机的分布式电源接入台区线损智能诊断方法。首先利用变异系数法对分布式电源接入台区特征指标进行关联性分析;其次,采用支持向量机算法衡量线损预测数据与真实数据相对误差,进而筛选出线损异常台区;然后,基于变异系数法得到的各指标权重更新异常台区数据,诊断线路高损成因;最后,采用25节点台区案例,进行方法验证。试验结果验证了所提方法的有效性。