Visual function and biofeedback training of patients with central vision loss:a review

Older individuals with macular diseases,such as age-related macular degeneration,experience central vision loss(CVL)due to degeneration of their photoreceptors and retinal cells.Patients with CVL may experience various vision impairments,including of visual acuity,fixation stability,contrast sensitivity,and stereoacuity.After CVL,most patients develop a preferred retinal locus outside the affected macular region,which serves as a new visual reference.In this review,we provide an overview of the visual function and impairment in individuals with CVL.In addition,the important role of biofeedback training on the visual function and activity of individuals with CVL is also reviewed.Accordingly,the location and development of the preferred retinal loci are discussed.Finally,this review discusses how to conduct biofeedback training to treat individuals with CVL.

Low central venous pressure reduces blood loss in hepatectomy

瞄准：为肝细胞癌(HCC ) 在肝切除术期间在失血上调查低中央静脉压(LCVP ) 的效果。方法：由封上的信封的方法， 50 个 HCC 病人被使随机化进 LCVP 组(n=25 ) 和控制组(n=25 ) 。在 LCVP 组， CVP 被病人的姿势的操作和药的管理在肝切除术期间在 90 毫米汞柱上面在 2-4 毫米汞柱和收缩血压(SBP ) 维持，当没有阴沉的 CVP，在控制组肝切除术习惯性地被执行时。病人的外科手术前的条件，失血的体积在肝切除术期间，输血的体积，一些医院停留，在肝、肾的功能的变化在二个组之间被比较。结果：处于病人的外科手术前的条件没有有效差量，最大的肿瘤尺寸，肝切除术的模式，脉管的吸藏的持续时间，手术时间， resected 肝纸巾的重量，手术后的复杂并发症的发生，在二个组之间的肝、肾的功能。LCVP 组比控制组在肝切除术期间有全部的 intraoperative 失血和失血的显著地更低的体积，是 903.9+/-180.8 mL 对 2 329.4+/-2 538.4 (W=495.5， P【0.01 ) 并且 672.4+/-429.9 mL 对 1 662.6+/-1 932.1 (W=543.5， P【0.01 ) 。在在二个组之间的切除术前和切除术以后的失血没有显著差别。医院停留的长度显著地作为与控制组相比在 LCVP 组被弄短，是 16.3+/-6.8 d 对 21.5+/-8.6 d (W=532.5， P【0.05 ) 。结论：LCVP 在技术是容易可完成的。CVP【or= 4 毫米汞柱的维护能帮助在肝切除术期间减少失血，弄短医院的长度留下来，并且没在肝或肾的功能上有有害效果。

Controlled low central venous pressure reduces blood loss and transfusion requirements in hepatectomy

AIM:To evaluate the effect of low central venous pressure(LCVP)on blood loss and blood transfusion in patients undergoing hepatectomy.METHODS:Electronic databases and bibliography lists were searched for potential articles.A meta-analysis of all randomized controlled trials(RCTs)investigating LCVP in hepatectomy was performed.The following three outcomes were analyzed:blood loss,blood transfusion and duration of operation.RESULTS:Five RCTs including 283 patients were assessed.Meta-analysis showed that blood loss in the LCVP group was significantly less than that in the control group(MD=-391.95,95%CI:-559.35--224.56,P<0.00001).In addition,blood transfusion in the LCVP group was also significantly less than that in the control group(MD=-246.87,95%CI:-427.06--66.69,P=0.007).The duration of operation in the LCVP group was significantly shorter than that in the control group(MD=-18.89,95%CI:-35.18--2.59,P=0.02).Most studies found no significant difference in renal and liver function between the two groups.CONCLUSION:Controlled LCVP is a simple and effective technique to reduce blood loss and blood transfusion during liver resection,and appears to have no detrimental effects on liver and renal function.

Effect of autologous blood donation on the central venous pressure, blood loss and blood transfusion during living donor left hepatectomy

AIM: Autologous blood donation (ABD) is mainly used to reduce the use of banked blood. In fact, ABD can be regarded as acute blood loss. Would ABD 2-3 d before operation affect the CVP level and subsequently result in less blood loss during liver resection was to be determined.METHODS: Eighty-four patients undergoing living donor left hepatectomy were retrospectively divided as group Ⅰ (GⅠ)and group Ⅱ (GⅡ) according to have donated 250-300 mL blood 2-3 d before living donor hepatectomy or not. The changes of the intraoperative CVP, surgical blood loss,blood products used and the changes of perioperative hemoglobin (Hb) between groups were analyzed and compared by using Mann-Whitney Utest.RESULTS: The results show that the intraoperative CVP changes between GⅠ (n = 35) and GⅡ (n = 49) up to graft procurement were the same, subsequently the blood loss,but ABD resulted in significantly lower perioperative Hb levels in GⅠ.CONCLUSION: Since none of the patients required any blood products perioperatively, all the predonated bloods were discarded after the patients were discharged from the hospital, It indicates that ABD in current series had no any beneficial effects, in term of cost, lowering the CVP, blood loss and reduce the use of banked blood products, but resulted in significant lower Hb in perioperative period.

光伏直流并网系统外部故障切除后有功恢复控制方法

光伏直流并网系统的集控信号局部丢失时,光伏单元难以在交流电网线路故障切除后恢复原有控制模式。为此,在分析恢复过程直流电压变化特性基础上,提出一种光伏直流并网系统外部故障切除后有功恢复控制方法。该方法利用直流电压阈值以及变流器固有动态响应时间,构成控制模式切换综合判据,以实现不同电网电压跌落程度下光伏单元控制模式的可靠切换。所提方法优势在于充分利用了变流器固有响应时间,不受交流故障过渡电阻影响,且无需改变变流器的控制器结构。仿真结果表明,所提方法在不同电网电压跌落下,均可有效实现故障清除后光伏单元控制模式的切换。

空气源热泵集中供暖系统调节理论分析

空气源热泵已广泛应用于华北等地区的集中供暖,但目前鲜有关于其调节方式的研究。为了提升空气源热泵的节能效果,本文建立空气源热泵集中供暖系统的数学模型,该模型考虑结除霜损失和启停损失,基于该模型提出3种适合于空气源热泵的调节方式,应用该模型对北京等7个城市的集中供暖系统进行研究。结果表明,结除霜损失修正和启停损失修正均对机组的耗电量及季节性能系数(SCOP)产生重要影响:结除霜损失修正使机组的耗电量增大3.85%~17.41%,SCOP降低3.72%~14.83%,启停损失修正的影响会随着供暖面积的增大逐渐降低;采用不同调节方式时,机组的耗电量变化不大,水泵节能80.97%~86.46%,系统节能8.47%~11.87%。

线损管理与智能电表集抄系统分析

阐述智能电表与集抄系统构成,探讨线损管理中的智能电表集抄系统功能,包括数据传输与存储、电能计量与冻结、计量智能参数,以及动态监控电量数据、线损远程监控。

提升集中供热系统运行稳定性方式探索

结合供热生产实践中电厂温度波动、热网失水治理、室温如何用于提升供热质量等问题进行了讨论,给出了储热及热电协同、全方位统计、实时视频监测站内失水、室温数据Pearson相关性系数等方面的分析与建议,以期为提升供热生产运行稳定性提供一些经验借鉴和优化思路。

Debris Flows Risk Analysis and Direct Loss Estimation:the Case Study of Valtellina di Tirano,Italy

Landslide risk analysis is one of the primary studies providing essential instructions to the subsequent risk management process. The quantification of tangible and intangible potential losses is a critical step because it provides essential data upon which judgments can be made and policy can be formulated. This study aims at quantifying direct economic losses from debris flows at a medium scale in the study area in Italian Central Alps. Available hazard maps were the main inputs of this study. These maps were overlaid with information concerning elements at risk and their economic value. Then, a combination of both market and construction values was used to obtain estimates of future economic losses. As a result, two direct economic risk maps were prepared together with risk curves, useful to summarize expected monetary damage against the respective hazard probability. Afterwards, a qualitative risk map derived using a risk matrix officially provided by the set of laws issued by the regional government, was prepared. The results delimit areas of high economic as well as strategic importance which might be affected by debris flows in the future. Aside from limitations and inaccuracies inherently included in risk analysis process, identification of high risk areas allows local authorities to focus their attention on the "hot-spots", where important consequences may arise and local(large) scale analysis needs to be performed with more precise cost-effectiveness ratio. The risk maps can be also used by the local authorities to increase population's adaptive capacity in the disaster prevention process.

Optimal central venous pressure during partial hepatectomy for hepatocellular carcinoma

BACKGROUND:Low central venous pressure(CVP) affects hemodynamic stability and tissue perfusion.This prospective study aimed to evaluate the optimal CVP during partial hepatectomy for hepatocellular carcinoma(HCC).METHODS:Ninety-seven patients who underwent partial hepatectomy for HCC had their CVP controlled at a level of 0 to 5 mmHg during hepatic parenchymal transection.The systolic blood pressure(SBP) was maintained,if possible,at 90 mmHg or higher.Hepatitis B surface antigen was positive in 90 patients(92.8%) and cirrhosis in 84 patients(86.6%).Pringle maneuver was used routinely in these patients with clamp/unclamp cycles of 15/5 minutes.The average clamp time was 21.4±8.0 minutes.These patients were divided into 5 groups based on the CVP:group A:0-1 mmHg;B:1.1-2 mmHg;C:2.1-3 mmHg;D:3.1-4 mmHg and E:4.1-5 mmHg.The blood loss per transection area during hepatic parenchymal transection and the arterial blood gas before and after liver transection were analyzed.RESULTS:With active fluid load,a constant SBP ≥90 mmHg which was considered as optimal was maintained in 18.6% in group A(95% CI:10.8%-26.3%);39.2% in group B(95% CI:29.5%-48.9%);72.2% in group C(95% CI:63.2%-81.1%);89.7% in group D(95% CI:83.6%-95.7%);and 100% in group E(95% CI:100%-100%).The blood loss per transection area during hepatic parenchymal transection decreased with a decrease in CVP.Compared to groups D and E,blood loss in groups A,B and C was significantly less(analysis of variance test,P【0.05).Compared with the baseline,the blood oxygenation decreased significantly when the CVP was reduced.Base excess and HCO 3-in groups A and B were significantly decreased compared with those in groups C,D and E(P【0.05).CONCLUSION:In consideration of blood loss,SBP,base excess and HCO 3-,a CVP of 2.1-3 mmHg was optimal in patients undergoing partial hepatectomy for HCC.

Effect of controlled low central venous pressure on renal function in major liver resection

Objective: To investigate the effects of low central venous pressure (LVCP) on blood loss and evaluate its influ- ence on renal function in patients undergoing hepatectomy. Methods: Forty-six patients, ASA classification I–III, undergoing liver resection were randomized into LCVP group (n = 23) and control group (n = 23). In LCVP group, CVP was maintained at 2–4 mmHg and MBP above 60 mmHg during hepatectomy, while in control group hepatectomy was performed routinely without lowering CVP. Volume of blood loss during hepatectomy, volume of blood transfusion, and changes of renal functions were compared between the two groups. Results: There were no significant differences in demographics, ASA score, type of hepatectomy, duration of inflow occlusion, operation time, weight of resected liver tissues, and renal functions between the two groups. LCVP group had a significantly lower volume of total intraoperative blood loss (P < 0.01) and RBC transfusion (P < 0.05). Conclusion: Lowering the CVP to less than 5 mmHg is a simple and effective technique to reduce blood loss and blood infusion during liver resection, and has no detrimental effects on renal functions.

Perioperative visual loss after spine surgery

Perioperative visual loss(POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult to determine. According to the American Society of Anesthesiologists Postoperative Visual Loss Registry, the most common causes of POVL in spine procedures are the two different forms of ischemic optic neuropathy: anterior ischemic optic neuropathy and posterior ischemic optic neuropathy, accounting for 89% of the cases. Retinal ischemia, cortical blindness, and posterior reversible encephalopathy are also observed, but in a small minority of cases. A recent multicenter case control study has identified risk factors associated with ischemic optic neuropathy for patients undergoing prone spinal fusion surgery. These include obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration. These risk factors are thought to contribute to the elevation of venous pressure and interstitial edema, resulting in damage to the optic nerve by compression of the vessels that feed the optic nerve, venous infarction or direct mechanical compression. This review will expand on these findings as well as the recently updated American Society of Anesthesiologists practice advisory on POVL. There are no effectivetreatment options for POVL and the diagnosis is often irreversible, so efforts must focus on prevention and risk factor modification. The role of crystalloids versus colloids and the use of α-2 agonists to decrease intraocular pressure during prone spine surgery will also be discussed as a potential preventative strategy.

老年性聋听觉系统及认知功能改变

老年性聋是60岁以上人群普遍存在的慢性疾病。本文回顾了老年性聋外周和中枢听觉系统改变,以及听力损失和认知下降的关系。老年性聋发病年龄、耳聋下降速度、外周和中枢神经系统变性存在个体化差异。外周听觉功能、中枢听觉功能和认知功能相互影响又彼此独立。是听力损失引起认知障碍、或是反之、抑或互为因果,这些都是目前研究的前沿问题。本文就老年性聋外周和中枢听觉功能、认知功能综合评估、综合管理等问题的既往文献和未来研究进行了阐述。

基于Sophon SC5+芯片构架的行人搜索算法与优化

传统的基于深度神经网络的行人搜索算法计算量大,在大规模部署时搜索性能低,导致算法在落地应用于硬件和预算有限的终端时面临成本高、速度慢的难题。针对以上问题,提出一种基于Sophon SC5+高性能推理芯片的行人检测与重识别算法,从算法到硬件自上而下地优化深度学习的效率。首先,利用轻量化的Ghost模块替换YOLOv5s的主干网络,从而大幅度降低模型的参数和计算量;其次,融入CBAM注意力机制,以增强算法的特征学习能力,并提高检测精度;然后,将中心损失约束和Non-local注意力机制加入行人重识别模块,并结合中心约束三元组损失和附加间隔交叉熵损失优化模型,以提升行人重识别算法性能;最后,基于Sophon SC+量化行人检测模型和行人重识别模型并生成最终的推理模型。在Market-1501与DukeMTMC-ReID数据集上的实验结果表明,相较于YOLOv4-tiny、ACRN、SVDNet等主流算法,行人检测算法与行人重识别算法的平均精度均值(mAP)至少提高了43.8和25.7个百分点。基于Sophon SC5+芯片实现int8量化后,所提算法的mAP虽然减小了1.7个百分点,但模型大小减小了74.4%,能够在大规模、城市级行人搜索系统中落地使用。

含光伏接入的中压配电网集中调控优化策略

随着并网光伏数量和容量的增加,中压配电网电压波动及网损过大等问题日益突出。为此计及中压配电网的通信条件与计算能力等特点,提出了一种面向中压配电网的分布式光伏集中调控优化策略,抑制中压配电网电压波动及网损过大。分析光伏并网对配电网电压及网损影响,构建了以中压配电网潮流平衡方程、节点电压、支路电流及系统运行为约束,以网损最小、电压波动最小和分布式电源消纳最大为目标的多目标优化控制模型;采用商用CPLEX对模型进行求解;最后结合算例仿真对模型进行了有效性验证。结果表明,所提优化控制模型可有效降低配电网电压波动,合理分配分布式电源出力,降低网络损耗,同时保证光伏利用率处于相对合理区间。

基于位置可学习视觉中心机制的零售商品检测方法

针对零售商品包装变形和重叠使得难以有效捕捉显著且多样化的特征信息,导致检测精度不高的问题,设计了位置可学习视觉中心(LLVC,location learnable visual center)机制,对YOLOX-s进行改进,取得了更高的检测精度。为有效应对商品包装变形和重叠现象,首先,通过轻量级多层感知机融合不同特征通道上的信息,以充分捕获全局上下文信息;接着,通过设计的LLVC增强局部特征表示能力,并利用空间信息为局部特征分配可学习的权重,提高辨别性局部特征的关注程度;最后,将交并比(IoU,intersection over union)损失函数替换为中心交并比(CIoU,centered intersection over union),并在此基础上引入功率参数α,有效降低了漏检率。实验结果表明,所提方法在零售商品识别(RPC,retail product checkout)数据集上取得91.3%的准确率,相比YOLOX-s提高了2.2%,并优于目前主流的轻量级目标检测算法;同时每秒帧率(FPS,frame per second)为97 frame/s,模型大小为9.48 MB,能够在计算资源受限的场景下,准确且实时地进行零售商品检测。

控制性低中心静脉压技术用于肝包虫病手术的研究进展

肝包虫病又称为肝棘球蚴病,这是一种主要由细粒棘球绦虫和多房棘球绦虫的幼虫累及于肝脏所引起的人兽共患性寄生虫疾病。青海省位于我国青藏高原东北部,是我国肝包虫病流行的严重区域,患者的生活因为该病而受到严重影响。随着医学的不断进步,近年来外科手术已经成为治疗肝包虫病的主要手段。由于肝脏血供十分丰富,为了更加有效提高肝包虫病手术的安全性,临床通过控制性低中心静脉压(CLCVP)技术以减少手术创面的出血量。但也有一些研究指出CLCVP技术在肝脏手术中存在一定滞后性。因此,探讨是否通过CLCVP技术以辅助外科手术从而有效控制肝包虫病的流行具有一定的现实意义。

智能电表及集抄技术在线损管理中的应用

传统线损管理一般采用周期较长的人工方式辨识线损情况,导致配电网降损效果较差,因此,本文提出了一种基于智能电表及集抄技术的线损管理方法。首先采用智能电表及集抄技术远程抄写并传输用户的电量数据;其次预处理采集的电量数据中的缺失值和异常噪声,并根据处理后的电量数据计算线损;最后以线损率最小化为目标制定管控措施,实现配电网的线损管理。实验结果表明,与管理前相比,采用本文设计的线损管理方法后,配电网的线损量降低了20.063 3 kWh,证明了智能电表及集抄技术在线损管理中的有效性与实用性。

MRI、CT检查对儿童先天性神经感音性听力下降内耳及听觉中枢畸形的临床应用价值

目的分析MRI、CT检查对儿童先天性神经感音性听力下降内耳及听觉中枢畸形的临床应用价值。方法选取2020年1月至2021年12月期间河南省儿童医院的60例重度神经感音性下降儿童为研究对象,采用MRI、CT检查方式进行诊断,统计分析检查及分型结果。结果本组儿童均完成了MRI检查,有18例患儿完成CT检查,检查结果显示有3例儿童为内听道发育畸形,占比5.00%,14例儿童前庭导水管扩大,占比23.33%,3例儿童骨迷路畸形,占比5.00%,6例儿童为窝神经畸形,占比10.00%,12例儿童为耳蜗畸形,占比20.00%,有耳蜗不发育和耳蜗发育不全两种类型;1例儿童为米歇尔畸形,占比1.67%,8例儿童为前庭畸形,占比13.33%,其中有一些患儿存在椭圆囊扩大,1例儿童为顶周融合,占比1.67%,4例儿童为半规管畸形,占比6.67%,另外8例儿童经MRI、CT检查显示结果没有异常,占比13.33%。结论MRI可以对内耳、蜗神经畸形及发育的状况进行准确的判断和评估,且能够判定畸形的轻重程度,CT检查则能够对骨性结构及通道异常进行较为准确的判断,通过联合MRI及CT检查能够更加准确的判定内耳及听觉中枢畸形病情和病情的分型,从而为临床制定人工耳蜗植入手术方案提供重要的信息,并对临床预防或判断儿童患者治疗期间的并发症有重要作用。

疏散照明中均布负荷的电压损失计算

将疏散照明中的均布负荷折算为集中负荷后进行电压损失计算,并导出公式;依据公式确定不同导线规格在达到最大电压损失时,最长的折算配电距离;模拟确定地铁区间疏散照明的配电方案。