Hydrophilic reentrant SLIPS enabled flow separation for rapid water harvesting

Water harvesting from air is desired for decentralized water supply wherever water is needed. When water vapor is condensed as droplets on a surface the unremoved droplets act as thermal barriers. A surface that can provide continual droplet-free areas for nucleation is favorable for condensation water harvesting. Here, we report a flow-separation condensation mode on a hydrophilic reentrant slippery liquid-infused porous surface (SLIPS) that rapidly removes droplets with diameters above 50 μm. The slippery reentrant channels lock the liquid columns inside and transport them to the end of each channel. We demonstrate that the liquid columns can harvest the droplets on top of the hydrophilic reentrant SLIPS at a high droplet removal frequency of 130 Hz/mm². The sustainable flow separation without flooding increases the water harvesting rate by 110% compared to the state-of-the-art hydrophilic flat SLIPS. Such a flow-separation condensation approach paves a way for water harvesting.

Condensation is a common phase-change phenomenon that is widely used in water harvesting (1–5). Dropwise condensation can form discrete droplets on a low-surface-energy substrate and promote the heat transfer coefficient up to 10 times higher than filmwise condensation due to the rapid removal of condensates (6, 7). However, the displacement of air inside the structures can lead to a higher pinning force on the droplets, resulting in flooding on the superhydrophobic surface (8, 9). By replacing the air trapped inside the surface structures with liquid lubricant, researchers developed the slippery liquid-infused porous surface (SLIPS) to further promote heat transfer performance (1, 10–13). When condensed droplets grow to a certain diameter, they shed off a vertical surface due to the negligible contact angle hysteresis (12). To accelerate the droplet removal, directional droplet movements were developed to regulate the removal of water droplets on SLIPS (2, 5). However, these surfaces rely on gravity to remove large droplets that remain on the surface as thermal barriers before shedding during condensation.Therefore, surfaces with partially hydrophilic and partially hydrophobic domains were developed to remove droplets from the condensing surface to the structures underneath. Such an amphiphilic surface has a hydrophobic top with a hydrophilic porous structure underneath (14, 15). During the condensation, droplets on the hydrophobic top are absorbed by the wetted hydrophilic structures underneath. However, the liquid film within the hydrophilic structures leads to partial or complete flooding at elevated heat fluxes due to the high pinning forces (9, 16, 17). Unlike the radiative cooling-induced dew harvesting in nature, droplets are directly condensed on the reentrant SLIPS by conduction and convection (18), where condensed droplets act as thermal barriers (19–21). Based on the condensation models (6, 22–24), each droplet contributes to the total thermal resistance, while smaller droplets have a lower thermal resistance. When a surface is only covered by small droplets (e.g., at the beginning of the condensation), the heat transfer coefficient is higher than that of a surface with larger droplets (25). Thus, rapid droplet nucleation and removal are desired to achieve a high heat transfer coefficient. Microchannels are applied to transport condensates as the flow resistances can be much smaller than those of micropillars. Hydrophilic slippery channels with or without biphilic coatings are used to enhance water harvesting, but they failed to separate the vapor and liquid as droplets emerged out of the channels or completely wetted the surfaces (1, 26–28). To suppress condensates from emerging out of the channel, the liquid column must be locked inside. The reentrant channels show a potential to lock the liquid inside due to their overhang structures. With a surface engineering approach, the reentrant structure has been modified to keep highly nonwetting liquids inside (29). However, the reentrant structures are wetted by liquids during condensation as the condensates are pinned inside the channels (30). Thus, the surface will transition to a complete wetting state at elevated heat fluxes.To address those challenges, on a hydrophilic reentrant SLIPS, we present a flow-separation condensation mode that sustains rapid droplet removal on top and transports liquid columns underneath. Our approach is to make reentrant channels with hydrophilic and slippery boundary lubrication. Once droplets are condensed on the top hydrophilic slippery surface, they are removed immediately to the reentrant channels underneath, resulting in sustainable flow separation. Such a new condensation mode could significantly reduce the thermal resistance by rapidly removing droplets with diameters above 50 µm, leading to an exceptional water harvesting rate. This work not only proposes a flow separation approach to enhance water harvesting but also provides a universal concept to design surfaces for condensation heat transfer.     

Repair of Congenital Right Atrial Aneurysm Associated With Wolff-Parkinson-White Syndrome in a 5-Year-Old Girl

This report describes our experience with a 5-year-old girl who had an extremely rare presentation of a right atrial aneurysm and associated Wolff-Parkinson-White syndrome. Before being referred to our department, she underwent an ineffective radiofrequency ablation for repeated episodes of paroxysmal supraventricular tachycardia that were causing dizziness, palpitations, and chest discomfort. We resected the aneurysm with good results; she was doing well and was in normal sinus rhythm at the time of her 1-year follow-up visit.     

导管射频消融治疗严重症状性室性早搏的初步研究

目的:探索导管射频消融治疗严重症状性室性早搏(室早)伴或不伴室早诱发的短阵室性心动过速(室速)的安全性、效率和方法学。方法:18例严重症状性室早患者入选本研究,术前室早数量平均(117±37)次/h。术前根据同步12导联体表心电图初步推测室性早搏产生部位,术中依据初步推测的室早产生部位采用心室激动顺序标测法与起搏标测法进行室早标测定位,大头消融电极标测到室早最早激动点较体表心电图QRS波提前25ms以上或消融电极起搏心电图QRS波图形与室早图形11/12以上一致时放电消融。结果:18例患者导管射频消融即时成功16例,术后室早数(6±2)次/h,较术前显著减少(P<0.05);随访12个月,18例中16例消融成功,成功率88.9%;无严重并发症发生。结论:导管射频消融治疗严重症状性室早伴或不伴室早诱发的短阵室速安全、有效,同步12导联体表心电图对室早的定位有重要的指导意义。     

Phospholamban p.Arg14del Cardiomyopathy: A Japanese Case Series

Phospholamban p.Arg14del is reported to cause hereditary cardiomyopathy with malignant ventricular tachycardia (VT) and advanced heart failure. However, the clinical courses of Japanese cardiomyopathy patients with phospholamban p.Arg14del remain uncharacterized. We identified five patients with this variant. All patients were diagnosed with dilated cardiomyopathy (DCM), developed end-stage heart failure and experienced VT requiring implantable cardioverter defibrillator discharge. Four patients survived after implantation of a left ventricular assist device (LVAD), while one patient who refused LVAD implantation died of heart failure. Based on the severe course of the disease, we propose genetic screening for phospholamban p.Arg14del in DCM patients.     

食道心房调搏终止妊娠期室上性心动过速疗效观察

目的：观察经食道心房调搏（TEAP）终止妊娠期阵发性室上性心动过速（PSVT）的临床疗效及安全性。方法：2003年1月～2013年3月收治的51例我院及白银市第一人民医院心内科就诊门诊或住妊娠期PVST患者,TEAP终止发作,观察窦性心律转复率。结果：51例患者TEAP均终止了PSVT发作,转复率100.0%。结论：TEAP转复妊娠期PSVT安全、有效、副反应少,值得在基层医院推广应用。     

隐匿性房室旁道心电图定位的临床价值评价

目的探讨隐匿性房室旁道心电It定位的临床价值。方法以我院2010年-2013年诊断收治的隐匿性房室旁道患者48例为研究对象。结果右侧旁道13例,在V1倒置12例,平坦3例,P-R间期均〉R—P-间期,左侧旁道35例,其中21例左前区域旁道,在I、aVLP-波倒置,在III、aVFP-波直立,P-R间期均〈R—P-间期;14例左后区域旁道,12例P-波在I、aVL直立、浅倒置、平坦,各种变化较大,P-R间期〉R—P-间期,2例左后间隔旁道在III、aVFP。波深倒置。结论隐匿性房室旁道诊断中采用体表心电图通过对P-波形态以及RP间期长短的观察能形成较为准确的定位。     

直立试验心率变化预测口服补液盐治疗体位性心动过速综合征的效果

目的 通过直立试验心率的变化预测口服补液盐(ORS)治疗体位性心动过速综合征(POTS)的效果.方法 选择北京大学第一医院儿科2005年7月至2013年9月收治的54例POTS患儿为研究对象,以20名健康儿童作为对照组.对POTS患儿治疗前进行症状严重程度评分及直立试验,给予ORS治疗3个月后再次进行症状严重程度评分及直立试验,根据症状评分减少程度是否大于50％将患儿分为治疗有效组及治疗无效组.应用受试者工作曲线评价卧立位心率差值及直立后10 min内最大心率对ORS治疗POTS疗效的预测价值.结果 POTS组患儿54例,年龄6～ 17(11.3±3.0)岁.对照组儿童20名,年龄10 ～ 12(11.0±0.8)岁.POTS组患儿卧立位心率差值明显高于对照组,差异有统计学意义[(41±10)比(20-±7)次/min,t=-10.441,P=0.000].POTS患儿治疗后临床症状评分较治疗前显著减低[(3.2±1.8)比(5.7±2.0)分,t=10.958,P＜0.001],其中有30例POTS患儿复查直立试验,治疗后卧立位心率差值较治疗前有显著降低[(33±11)比(41±ll)次/min,t=2.956,P=0.006].54例POTS患儿治疗有效26例,治疗无效28例.治疗有效组治疗前卧立位心率差值明显高于治疗无效组[(46±10)比(37±9)次/min,t=-3.582,P=0.001],治疗前直立后10 min内最大心率明显高于治疗无效组[(122±12)比(113±10)次/min,t=-2.693,P=0.010].当卧立位心率差值为41次/min时,预测应用ORS治疗POTS有效的敏感度和特异度分别为72％和70％;当直立后10 min内最大心率达到123次/min时,预测应用口服补液盐治疗POTS有效的敏感度和特异度分别为48％和78％;卧立位心率差值联合直立后10 min内最大心率预测ORS治疗POTS有效的敏感度为84％,特异度为56％.结论 采用POTS患儿直立试验中心率变化预测口服补液盐疗效,具有较好的临床价值.     

非折返房性心动过速P波形态的定位诊断

目的:通过分析房性心动过速(房速)时心电图P波形态特征判定房速起源。方法:对37例成功行单靶点消融治疗的房速患者的P波形态和参数与消融靶点进行对比分析。计算房速时PR与PP间期比值(PRI)评价激动在房室结传导的时程变化;计算P波与PR间期的比值(PCI)评价激动在房内传导的变化。结果:29例靶点位于右房,8例位于左房。左房房速在下壁导联P波振幅显著增高。右房后壁的PR(I0.52±0.05)数值在各部位中最大,无冠窦、冠状窦口和右房侧壁的PCI(0.24±0.04)值最小。结论:aVL和V1导联P波形态对区分左房和右房房速具有重要的临床意义,Ⅱ、Ⅲ、aVF导联可为起源点位于心房上下提供线索,PRI、PCI有助于房速起源的判定。     

Beta-adrenoceptor blocking effects and pharmacokinetics of pindolol

Summary The beta-adrenoceptor blocking effects of pindolol were compared with those of a placebo in a double-blind trial in twelve hypertensive Africans. Heart rate and arterial blood pressure were measured at rest and immediately after exercise, before and at intervals up to 8 h after oral administration of the drugs. Plasma levels of pindolol were also determined. Pindolol reduced systolic blood pressure and antagonised exercised-induced tachycardia. The mean time to peak level of pindolol was 1.9 h and the mean half-life was 4.2 h. Comparison of plasma levels of pindolol and beta-adrenoceptor blocking activity showed good correlation between them. It is concluded that the pharmacokinetics and beta-blocking effects of pindolol in Africans are not dissimilar from published data for other races.     

射频消融治疗室上性心动过速的疗效

目的研究分析射频消融治疗室上性心动过速的疗效及不良反应。方法回顾性分析我院2009年1月至2011年12月我院收治的52例射频消融治疗室上性心动过速的患者资料,观察患者的治疗效果和不良反应。结果 52例患者成功率为100%,其中旁道参与的室上性心动过速患者28例,成功28例;房室结折返心动过速24例,成功24例。手术后并发症发生1例,随访半年中,有2例复发。结论射频消融治疗室上性心动过速的疗效较好,技术先进,损伤小,手术后不良反应少,复发率低,值得在临床应用。