Wettability and Surface Roughness of Parylene C on Three-Dimensional-Printed Photopolymers

The use of poly-(para-chloro-xylylene) (Parylene C) in microelectromechanical systems and medical devices has increased rapidly. However, little research has been conducted on the wettability and surface roughness of Parylene C after being soaked in solutions. In this study, the contact angle and surface roughness (arithmetic average of roughness) of Parylene C on three-dimensional (3D)-printed photopolymer in 10% sodium hydroxide, 10% ammonium hydroxide, and 100% phosphate-buffered saline (PBS) solutions were investigated using a commercial contact angle measurement system and laser confocal microscope, respectively. The collected data indicated that 10% ammonium hydroxide had no major effect on the contact angle of Parylene C on a substrate, with a Shore A hardness of 50. However, 10% sodium hydroxide, 10% ammonium hydroxide, and 100% PBS considerably affected the contact angle of Parylene C on a substrate with a Shore A hardness of 85. Substrates with Parylene C coating exhibited lower surface roughness than uncoated substrates. The substrates coated with Parylene C that were soaked in 10% ammonium hydroxide exhibited high surface roughness. The aforementioned results indicate that 3D-printed photopolymers coated with Parylene C can offer potential benefits when used in biocompatible devices.     

Investigation of Adhesion Properties of Tire—Asphalt Pavement Interface Considering Hydrodynamic Lubrication Action of Water Film on Road Surface

To obtain the tire–pavement peak adhesion coefficient under different road states, a field measurement and FE simulation were combined to analyze the tire–pavement adhesion characteristics in this study. According to the identified texture information, the power spectral distribution of the road surface was obtained using the MATLAB Program, and a novel tire hydroplaning FE model coupled with a textured pavement model was established in ABAQUS. Experimental results show that here exists an “anti-skid noncontribution area” for the insulation and lubrication of the water film. Driving at the limit speed of 120 km/h, the critical water film thickness for the three typical asphalt pavements during hydroplaning was as follows: AC pavement, 0.56 mm; SMA pavement, 0.76 mm; OGFC pavement, 1.5 mm. The road state could be divided into four parts dry state, wet sate, lubricated state, and ponding state. Under the dry road state, when the slip rate was around 15%, the adhesion coefficient reached the peak value, i.e., around 11.5% for the wet road state. The peak adhesion coefficient for the different asphalt pavements was in the order OGFC > SMA > AC. This study can provide a theoretical reference for explaining the tire–pavement interactions and improving vehicle brake system performance.     

Optimizing the Thermomechanical Process of Nickel-Based ODS Superalloys by an Efficient Method

Thermo-mechanical process of nickel-based oxide dispersion strengthened (ODS) superalloys is critical to produce desired components. In this study, an efficient method of consolidating powder is introduced to optimize the preparation process, microstructure and properties of nickel-based ODS superalloys. The influences of consolidation temperature, strain rate and ball milling time on the hardness of nickel-based superalloys were studied. The relationship among process, microstructure and hardness was established, the nanoparticles strengthening and grain boundary strengthening in nickel-based ODS superalloys were discussed. The results indicate that long ball milling time, moderately low consolidation temperature and high strain rates are beneficial to improving properties of nickel-based superalloys. Moreover, dispersion strengthening of nanoparticles and grain boundary strengthening play important roles in enhancing nickel-based ODS superalloys.     

First-Principles Study of Silicon–Tin Alloys as a High-Temperature Thermoelectric Material

Silicon–germanium (SiGe) alloys have sparked a great deal of attention due to their exceptional high-temperature thermoelectric properties. Significant effort has been expended in the quest for high-temperature thermoelectric materials. Combining density functional theory and electron–phonon coupling theory, it was discovered that silicon–tin (SiSn) alloys have remarkable high-temperature thermoelectric performance. SiSn alloys have a figure of merit above 2.0 at 800 K, resulting from their high conduction band convergence and low lattice thermal conductivity. Further evaluations reveal that Si_0.75Sn_0.25 is the best choice for developing the optimum ratio as a thermoelectric material. These findings will provide a basis for further studies on SiSn alloys as a potential new class of high-performance thermoelectric materials.     

Intrathoracic infections in Hodgkin lymphoma (HL) patients may cooperate with HL to trigger hemophagocytic lymphohistiocytosis: A retrospective study

Hodgkin lymphoma (HL)-related hemophagocytic lymphohistiocytosis (HLH) has been reported in the literature; however, there is almost no literature on the factors related to HL triggering HLH.One hundred forty patients with HL were retrospectively analyzed. The incidence of HL-related HLH (we call HL-related HLH as HL-HLH). And all HL-HLH patients in our cohort had HLH as the first manifestation and its clinical characteristics and the role of intrathoracic infection (ITI) in triggering HLH are discussed.The 140 patients with HL mainly included mixed-cellularity classic HL (MCCHL) in 81 (57.9%), nodular sclerosis classic HL (NSCHL) in 36 (25.7%), and lymphacyte-rich classic HL in 14 (10.0%) patients. Of the 137 patients who underwent chest computed tomography scans on admission, 44 had ITI, and most of these ITI were mildly ill and had no respiratory symptoms. Among 140 HL patients, 8 patients from MCCHL were diagnosed as HL-HLH. Among 81 MCCHL patients, 26 patients with ITI had a significantly higher incidence of HL-HLH than those without ITI (26.9% vs 1.8%, P = .002). The median survival time of 8 cases of HL-HLH was only 2 months.When HL patients were first admitted to the hospital, 5.7% had HLH as the first manifestation, and 32.1% had ITI. These ITI can cooperate with HL to trigger HLH, despite their mild illness. The prognosis of HL-HLH was poor.     

神经干细胞移植术治疗视网膜退行性疾病

各种退行性视网膜病变缺乏常规的治疗方法,通过干细胞移植,使其整合入视网膜各层并且分化为目标细胞,以重建视网膜功能,给不可逆性盲眼患者带来了曙光。近年来视网膜干细胞移植的试验性研究取得了重大的进展。现就视网膜神经干细胞移植的供体材料来源、诱导分化及影响因素和试验研究的最新进展作一综述。