Dynamic modeling of the outlet of a pulsatile pump incorporating a flow-dependent resistance

Outlet tube models incorporating a linearly flow-dependent resistance are widely used in pulsatile and rotary pump studies. The resistance is made up of a flow-proportional term and a constant term. Previous studies often focused on the steady state properties of the model. In this paper, a dynamic modeling procedure was presented. Model parameters were estimated by an unscented Kalman filter (UKF). The subspace model identification (SMI) algorithm was proposed to initialize the UKF. Model order and structure were also validated by SMI. A mock circulatory loop driven by a pneumatic pulsatile pump was developed to produce pulsatile pressure and flow. Hydraulic parameters of the outlet tube were adjusted manually by a clamp. Seven groups of steady state experiments were carried out to calibrate the flow-dependent resistance as reference values. Dynamic estimation results showed that the inertance estimates are insensitive to model structures. If the constant term was ignored, estimation errors for the flow-proportional term were limited within 16% of the reference values. Compared with the constant resistance, a time-varying one improves model accuracy in terms of root mean square error. The maximum improvement is up to 35%. However, including the constant term in the time-varying resistance will lead to serious estimation errors.     

Effect of dehydroepiandrosterone administration on recovery from mix-type exercise training-induced muscle damage

This study aimed to determine the role of DHEA-S in coping against the exercise training mixing aerobic and resistance components. During 5-day successive exercise training, 16 young male participants (19.2 ± 1.2 years) received either a placebo (flour capsule) or DHEA (100 mg/day) in a double-blinded and placebo-controlled design. Oral DHEA supplementation significantly increased circulating DHEA-S by 2.5-fold, but a protracted drop (~35 %) was observed from Day 3 during training. In the Placebo group, only a minimal DHEA-S reduction (~17 %) was observed. Changes in testosterone followed a similar pattern as DHEA-S. Muscle soreness was elevated significantly on Day 2 for both groups to a similar extent. Lower muscle soreness was observed in the DHEA-supplemented group on Day 3 and Day 6. In the Placebo group, training increased circulating creatine kinase (CK) levels by approximately ninefold, while only a threefold increase was observed in the DHEA-supplemented group. This mix-type exercise training improved glucose tolerance in both groups, while lowering the insulin response to the glucose challenge, but no difference between treatments was observed. Our results suggest that DHEA-S may play a role in protecting skeletal muscle from exercise training-induced muscle damage.     

A new protocol for the preparation of superconducting KBi2

A superconducting KBi₂ sample was successfully prepared using a liquid ammonia (NH₃) technique. The temperature dependence of the magnetic susceptibility (M/H) showed a superconducting transition temperature (T_c) as high as 3.6 K. In addition, the shielding fraction at 2.0 K was evaluated to be 87%, i.e., a bulk superconductor was realized using the above method. The T_c value was the same as that reported for the KBi₂ sample prepared using a high-temperature annealing method. An X-ray diffraction pattern measured based on the synchrotron X-ray radiation was analyzed using the Rietveld method, with a lattice constant, a, of 9.5010(1) Å under the space group of Fd$\bar{3}$m (face-centered cubic, no. 227). The lattice constant and space group found for the KBi₂ sample using a liquid NH₃ technique were the same as those reported for KBi₂ through a high-temperature annealing method. Thus, the superconducting behavior and crystal structure of the KBi₂ sample obtained in this study are almost the same as those for the KBi₂ sample reported previously. Strictly speaking, the magnetic behavior of the superconductivity was different from that of a KBi₂ sample reported previously, i.e., the KBi₂ sample prepared using a liquid NH₃ technique was a type-II like superconductor, contrary to that prepared using a high-temperature annealing method, the reason for which is fully discussed. These results indicate that the liquid NH₃ technique is effective and simple for the preparation of a superconducting KBi₂. In addition, the topological nature of the superconductivity for KBi₂ was not confirmed.

A superconducting KBi₂ sample was successfully prepared using a liquid ammonia (NH₃) technique.     

分阶段延续护理模式在COPD稳定期患者中的应用

目的探讨分阶段延续护理模式在COPD稳定期患者中的应用效果。方法采用便利抽样法,选取2019年5月—2020年4月成都市第三人民医院收治的220例COPD患者为研究对象,将2019年5—10月收治的110例患者纳入对照组,2019年11月—2020年4月收治的110例患者纳入观察组。对照组采用常规护理,观察组采用分阶段延续护理模式。干预前后采用自我护理能力测定量表(ES-CA)和简明健康测量量表(SF-36)评估两组患者的自我护理能力和生活质量。结果干预后观察组患者的ES-CA总分为(110.62±12.09)分,高于对照组的(102.87±11.54)分,差异有统计学意义(t=4.863,P<0.01)。干预后观察组患者的SF-36量表各维度得分均高于对照组,差异均有统计学意义(P<0.01)。结论应用分阶段延续护理模式可以充分调动患者的积极性,有效地提高患者的自我护理能力和生活质量。     

Effect of exergaming versus combined exercise on cognitive function and brain activation in frail older adults: A randomised controlled trial

BackgroundCognitive impairment is prevalent among frail older adults. Traditional exercise and exergaming positively affect cognition in healthy older people. However, few studies have investigated the effects of exergaming on cognition and brain activation in frail older adults.ObjectiveThis study compared the effect of Kinect based exergaming (EXER) and combined physical exercise (CPE) training on cognitive function and brain activation in frail older adults in Taiwan. We hypothesised that EXER would be superior to CPE in this population.MethodsWe randomised 46 community-dwelling frail older adults to the EXER or CPE group for 36 sessions (three 60-min training sessions per week) over 12 weeks. Outcome measures for cognitive function included global cognition measured by the Montreal Cognitive Assessment, executive function measured by the Executive Interview 25, verbal memory measured by the Chinese version of the California Verbal Learning Test, attention measured by the Stroop Colour and Word Test and Trail Making Test (part B), and working memory measured by spatial n-back tests. Prefrontal cortex activation during the global cognition test was documented with functional near-infrared spectroscopy (fNIRS).ResultsBoth groups improved significantly in global cognition (P < 0.05), executive function (P < 0.05), and attention (P < 0.05) after the 12-week intervention. The group × time interaction indicated that EXER training significantly enhanced global cognition more than CPE training (F(1,44) = 5.277, P = 0.026). Moreover, only the EXER group showed significant improvements in verbal (P < 0.05) and working (P < 0.05) memory after the intervention. The fNIRS hemodynamics data revealed decreased activation in prefrontal cortices of both groups (P < 0.05) during the post-training cognitive assessment, thereby suggesting greater neural efficiency; however, we found no significant group difference.ConclusionIn frail older adults, exergaming and CPE could improve cognitive function, most likely by increasing neural efficiency. Moreover, exergaming may be superior to CPE, particularly in improving global cognition.     

MSCT与MRI对疑似急性胰腺炎的临床诊断效果对比分析

目的:探讨多层螺旋CT(MSCT)与MRI在急性胰腺炎诊断中的临床应用价值。方法:回顾性分析临床疑似急性胰腺炎66例患者的临床、MSCT、MRI资料,采用MSCT与MRI进行检查,将两种影像检查结果与病理结果进行比较得出结论。结果:66例临床疑似为急性胰腺炎患者,MSCT诊断急性胰腺炎为阳性43例,占65.15%(43/66);MSCT平扫主要表现为胰腺体积增大,密度均匀或不均匀,出血区为高密度灶,液化坏死为低密度灶,增强扫描胰腺呈均匀或不均匀明显强化,液化坏死区无强化。MRI诊断急性胰腺炎为阳性51例,占77.27%(51/66);MRI主要表现为胰腺体积肿大,胰腺及胰周积液呈T1低T2高信号。病理诊断急性胰腺炎结果为阳性52例,占78.79%(52/66)。MRI对急性胰腺炎诊断的敏感性、准确性(96.15%、95.45%)明显高于MSCT(75.00%、74.24%),差异有统计学意义(χ²=7.790、9.959,P<0.05)。MRI对急性胰腺炎诊断的特异性(92.86%)高于MSCT(71.43%),但差异无统计学意义(χ²=0.974、P=0.324)。结论:MRI对急性胰腺炎诊断的敏感性、特异性、准确性均高于MSCT,对于急性胰腺炎MSCT检查有禁忌证、需要多次复查的患者,MRI检查具有更大的优势。     

两种不同灌注方法对肩关节镜下手术出血与视野显露的影响

目的探讨改良加压灌注和常规重力灌注对肩关节镜下手术出血与视野显露的影响。方法选取我院2018-01/2019-07期间因肩袖撕裂收住我院骨科拟行肩关节镜手术治疗的患者60例,ASA分级Ⅰ或Ⅱ级,采用随机数字表法分为观察组(n=30)和对照组(n=30)。观察组应用改良气压止血仪加压灌注,对照组应用常规重力灌注,监测并记录关节腔压力(mmHg)、关节腔灌注引流液中红细胞计数(个)、灌注液总量(L)、手术时间(min)、术后肩关节肿胀度(cm)。结果观察组第1次更换灌注液时关节腔压力高于对照组,关节腔灌注引流液中的红细胞计数及手术时间少于对照组,差异有统计学意义(P<0.05);2组灌注液总量及术后肩关节肿胀度无统计学意义(P>0.05)。结论在肩关节镜手术中使用改良加压灌注法,具有操作简便、压力稳定、视野清晰、手术时间短等优点,值得临床推广使用。