Abstract Crude oil is the most exploited energy source and the best way to increase the yield of oil recovery is the use of middle‐phase microemulsions. But the consecutive formation of water‐in‐oil emulsions needs oil–water separation. Reversible middle‐phase microemulsions were prepared with tetradecane (equivalent alkane for crude oil from Xinjiang oilfields, China) and aqueous solutions containing 1‐pentanol, N , N ‐dimethyltetradecylamine and NaCl, and stimulated with CO 2 . By adding and removing CO 2 , the conductivity of aqueous solutions without NaCl increases from 20 μS/cm to 3.6 mS/cm reversibly. Additionally, the surface and interfacial tensions of aqueous solution show reversible changes. The middle‐phase microemulsion is stable in CO 2 atmosphere. After removing CO 2 , it becomes separated into oil and aqueous phases. However, by sparging CO 2 and standing for 2 days, it becomes middle‐phase microemulsion again. This research is expected to launch a brand‐new avenue for the CO 2 ‐stimulated reversible microemulsification.
To evaluate the effectiveness of Curved Diffusion Needle in unilateral percutaneous vertebroplasty (PVP) by compared with bilateral PVP.A clinical data of 93 patients with osteoporotic vertebral compression fracture (OVCF) treated with PVP between January 2020 and January 2021 was retrospectively analyzed, including 47 patients underwent unilateral PVP assisted with Curved Diffusion Needle (unilateral group) and 46 patients underwent bilateral PVP (bilateral group). There was no significant difference in gender, age, cause of injury, time from injury to operation, T value of bone mineral density, AO classification, distribution of injured vertebrae, and preoperative visual analogue scale (VAS) score, Oswestry disability index (ODI), relative height of injured vertebrae, and Cobb angle between the two groups ( P>0.05). The operation time, the amount of bone cement injection, the incidence of bone cement leakage, the bone cement diffusion distribution, VAS score, ODI, the relative height of injured vertebrae, and Cobb angle were recorded and compared between the two groups.All operations successfully completed. The operation time was significantly shorter in unilateral group than in bilateral group ( t=-13.936, P=0.000), and the amount of bone cement injection was significantly less in unilateral group than in bilateral group ( t=-13.237, P=0.000). The incidence of bone cement leakage in unilateral group was 19.14%, which was significantly lower than that in bilateral group (39.13%) ( χ2=4.505, P=0.034). The score of bone cement distribution in unilateral group was 7.0±1.3, of which 41 cases were excellent and 6 cases were well. The score of bilateral group was 7.4±0.8, of which 43 cases were excellent and 3 cases were well. There was no significant difference in score and grading of bone cement distribution between the two groups ( t=-1.630, P=0.107; Z=-1.013, P=0.311). All patients were followed up and the follow-up time was 3-10 months (mean, 6.5 months) in unilateral group and 3-10 months (mean, 6.1 months) in bilateral group. The VAS score, ODI, the relative height of injured vertebrae, and Cobb angle at 24 hours after operation and last follow-up were significantly better than those before operation in the two groups ( P<0.05). There were significant differences in all indicators between 24 hours after operation and last follow-up ( P<0.05). There was no significant difference in all indexes between the two groups ( P>0.05) at the same time point after operation. During follow-up, there was no complication such as contralateral vertebral collapse, refracture, adjacent vertebral fracture, or local kyphosis in the two groups.Unilateral PVP assisted with Curved Diffusion Needle for OVCF is beneficial to the distribution of bone cement, which can not only achieve similar effectiveness to bilateral PVP, but also achieve shorter operation time, less bone cement injection, and lower risk of bone cement leakage.通过与双侧穿刺经皮椎体成形术（percutaneous vertebroplasty，PVP）比较，探讨采用弯角弥散导针行单侧穿刺PVP的疗效。.回顾性分析2020年1月—2021年1月，行PVP治疗的93例骨质疏松性椎体压缩性骨折（osteoporotic vertebral compression fracture，OVCF）患者的临床资料。其中，47例采用弯角弥散导针行单侧穿刺PVP（单侧组），46例行双侧穿刺PVP（双侧组）。两组患者性别、年龄、致伤原因、受伤至手术时间、骨密度T值、骨折AO分型、伤椎分布以及术前疼痛视觉模拟评分（VAS）、Oswestry功能障碍指数（ODI）、伤椎相对高度、Cobb角等一般资料比较，差异均无统计学意义（ P>0.05），具有可比性。记录并比较两组手术时间、骨水泥注射量、骨水泥渗漏率、骨水泥弥散分布情况以及VAS评分、ODI、伤椎相对高度及Cobb角。.两组患者均顺利完成手术，单侧组手术时间较双侧组缩短（ t=−13.936， P=0.000），骨水泥注射量较双侧组减少（ t=−13.237， P=0.000）。术中单侧组骨水泥渗漏发生率为19.14%，低于双侧组的39.13%，差异有统计学意义（ χ2=4.505， P=0.034）。单侧组骨水泥分布评分为（7.0±1.3）分，其中优41例、良6例；双侧组评分为（7.4±0.8）分，其中优43例、良3例；两组骨水泥评分以及等级评价差异均无统计学意义（ t=−1.630， P=0.107； Z=−1.013， P=0.311）。两组患者均获随访，单侧组随访时间3～10个月，平均6.5个月；双侧组为3～10个月，平均6.1个月。组内术后24 h及末次随访时VAS评分、ODI以及伤椎相对高度、Cobb角均优于术前，差异有统计学意义（ P<0.05）；上述指标术后24 h与末次随访时比较，差异亦有统计学意义（ P<0.05）。两组间术后两时间点上述指标比较，差异均无统计学意义（ P>0.05）。随访期间两组均未出现伤椎对侧塌陷、再骨折、邻椎骨折及局部后凸畸形等并发症。.单侧穿刺PVP治疗OVCF术中采用弯角弥散导针，有利于骨水泥分布，不仅能获得与双侧穿刺PVP相似疗效，且手术时间更短、骨水泥注射量更少、骨水泥渗漏发生风险更低。.
A new glucose-responsive polymeric composite membrane that provided pulsatile insulin release was developed in our laboratory previously. To develop a clinically useful insulin delivery system, this study was designed to investigate factors influencing insulin stability during delivery by this membrane. The effects of stirring, release duration, insulin concentration and surfactant on insulin stability were studied under both incubation and delivery conditions in a buffer solution at 37 degrees C. The structural change of insulin was characterized by reverse-phase HPLC and circular dichroism. Hydrophobicity of various contact surfaces was determined by contact angle measurement. The results indicated that insulin concentration played an important role in the insulin stability, followed by stirring. Treating the membrane with a non-ionic surfactant prevented insulin denaturation during delivery through the membrane.
Chip attach is the bottleneck operation in semiconductor assembly. Chip attach scheduling is in nature unrelated parallel machine scheduling considering practical issues, for example, machine-job qualification, sequence-dependant setup times, initial machine status, and engineering time. The major scheduling objective is to minimize the total weighted unsatisfied Target Production Volume in the schedule horizon. To apply Q-learning algorithm, the scheduling problem is converted into reinforcement learning problem by constructing elaborate system state representation, actions, and reward function. We select five heuristics as actions and prove the equivalence of reward function and the scheduling objective function. We also conduct experiments with industrial datasets to compare the Q-learning algorithm, five action heuristics, and Largest Weight First (LWF) heuristics used in industry. Experiment results show that Q-learning is remarkably superior to the six heuristics. Compared with LWF, Q-learning reduces three performance measures, objective function value, unsatisfied Target Production Volume index, and unsatisfied job type index, by considerable amounts of 80.92%, 52.20%, and 31.81%, respectively.
Polar metals, commonly defined by the coexistence of polar structure and metallicity, are thought to be scarce because free carriers eliminate internal dipoles that may arise owing to asymmetric charge distributions. By using first-principle electronic structure calculations, we explored the possibility of producing metallic states in the polar/nonpolar KNbO3/BaTiO3 superlattice (SL) composed of two prototypical ferroelectric materials: BaTiO3 (BTO) and KNbO3 (KNO). Two types of polar/nonpolar interfaces, p-type (KO)-/(TiO2)0 and n-type (NbO2)+/(BaO)0, which can be constituted into two symmetric NbO2/BaO-NbO2/BaO (NN-type) and KO/TiO2-KO/TiO2 (PP-type) SL, as well as one asymmetric KO/TiO2-NbO2/BaO (PN-type) SL. The spatial distribution of ferroelectric distortions and their conductive properties are found to be extraordinarily sensitive to the interfacial configurations. An insulator-to-metal transition is found in each unit cell of the symmetric interfacial SL models: one exhibiting quasi-two-dimensional n-type conductivity for NN-type SL, while the other being quasi-two-dimensional p-type conductivity for PP-type SL. The anisotropic coexistence of in-plane orientation of free carriers and out-of-plane orientation of ferroelectric polarization in KNO/BTO SL indicates that in-plane free carriers can not eliminate the out-of-plane dipoles. Our results provide a road map to create two-dimensional polar metals in insulating perovskite oxide SL, which is expected to promote applications of new quantum devices.
Bioinspired honeycomb-like porous films with switchable properties have drawn much attention recently owing to their potential application in scenarios in which the conversion between two opposite properties is required. Herein, the CO2-gas-triggered ON/OFF switching wettability of biocompatible polylactic acid (PLA) honeycomb porous films is fabricated. Highly ordered porous films with diameters between 2.0 and 2.8 μm are separately prepared from complexes of nonresponsive PLA and a CO2-sensitive melamine derivative [N2,N4,N6-tris(3-(dimethylamino)propyl)-1,3,5-triazine-2,4,6-triamine, MET] via the breath figure method. The hydrophilic CO2-sensitive groups can be precisely arranged in the pore's inner surface and/or top surface of the films by simply changing the PLA/MET ratio. The sensitive groups in the pore's inner surface act as a switch triggered by CO2 gas controlling water to enter the pores or not, thus resulting in ON/OFF switching wettability. The largest response of the water contact angle of honeycomb films reaches 35°, from 100 to 65°, leading to an obvious hydrophobic–hydrophilic conversion. The improved surface wettability enhances the interaction between the cell and honeycomb film surface, thus resulting in a better cell attachment. Such smart properties accompanying the biocompatible polymer and biological gas trigger facilitate possible biomedical and bioengineering applications in the future for these films.
We introduce two types of dielectric metasurfaces, consisting of 3 × 3 regions, which manipulate wavefront by different feature heights. Both polarization-dependent and polarization-independent metasurfaces are realized for phase depth of 0 ∼ 2π at 1550 nm, with considerable average transmittance of 80.1 and 85.1 %, respectively. The phase modulation capability can be extended over a broadband range of 1460.1-1618.0 nm for optical communications, by carefully designing nanofeature sizes. Moreover, the entire metasurfaces with nanofeatures of varying heights can be fabricated in a single process by using direct laser writing with high-precision, which is beneficial for mass production and promising in developing efficient and ultracompact devices.
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