Fabrication, characterization, and chemical sensing of silicon dioxide microcantilevers

The objective of this work is to design and fabricate an advanced silicon dioxide microcantilever sensor and to investigate chemical and biological sensing by microtechnology. Microcantilever sensor technology has many advantages including fast response time, lower cost of fabrication, the possibility of sensor arrays with small overall dimensions, the ability to explore microenvironments, and improved portability for field applications. For all of these advantages, microcantilever chemical and biological sensors have drawn more and more attention. So far, all other microcantilevers were designed and fabricated for AFM applications. We developed a novel SiO2 microcantilever especially for chemical and biological sensor applications. First of all, a round tip was added at the end of the microcantilever to ease laser beam injection and 2 μm in thickness was designed to reduce noise disturbance in chemical or biological sensing. Secondly, the SiO2 microcantilever induces much larger deflection compared with the commonly used Si microcantilever due to the SiO2\u27s lower Young\u27s modulus. The SiO2 microcantilever thus has much higher sensitivity than the commonly used Si microcantilevers. So, for the chemically specific reaction between SiO2 and HF, it is feasible to detect femtomolar concentrations of hydrogen fluoride using SiO2microcantilever. Silicon plasma dry etching was employed to release the SiO2 cantilever from bulk silicon. The spring constant of the cantilevers was measured to be 0.104 N/m. A fabricated SiO2 microcantilever was used to detect femtomolar concentrations of hydrogen fluoride (HF), a decomposition component of nerve agents. Also, a SU-8 polymer microcantilever was made by microfabrication techniques. Besides optical detection of microcantilever deflection in a microcantilever sensor system, another detection method known as piezoresistive detection was also developed. A piezoresistive microcantilever was successfully designed and fabricated. The microcantilever was also developed to monitor impulses. In related research, a superhydrophobic perfluorocarbon nanoneedle surface was successfully synthesized. The water contact angle of this perfluorocarbon surface was measured at 179.8°, which is a record-high contact angle. This research aims at developing microcantilevers with one side covered by superhydrophobic film. In microcantilever surface modification, usually in solution, one surface is fully modified while another side keeps integrated. Maximum differential surface stress is then induced. The superhydrophobic surface was synthesized for this purpose

Technology for Improving Life of Thermal Recovery Well Casing

In steam injection process, casing is heated by steam, the change of casing temperature produces thermal stresses in the casing, the casing deforms when stresses exceed the yield point of its material. Casing failure is becoming increasingly prominent in thermal recovery wells, which severely restricts the development effect of such reservoirs, improving casing life of thermal recovery well has become a urgent problem to be solved. Through on-site survey and analysis, reasons for casing damage were determined as follows: strength change by high temperature, sand flow over of oil formation, poor cementing, unfavorable heat insulation and bad material for casing. In order to improve casing life, the supporting measures are introduced, the measures include pre-stress cementing technology, using casing head, thermal stress compensator, high-performance insulation tubing, high temperature cement slurry system, FRT110H special casing, and early sand control completion technology. Field application of these measures has gotten better effect in Shengli oilfield in recent years, the damage rate of thermal recovery well has decreased obviously, and this can provide reference for the efficient development of similar reservoirs at home and abroad.Key words: Casing failure; Thermal recovery wells; Special casing; Cementing; Sand control completio

Depressive Syndromes in Autoimmune Disorders of the Nervous System: Prevalence, Etiology, and Influence

Autoimmune diseases of the nervous system (ADNS) consist of a group of severely disabling disorders characterized by abnormal immune attack against protein components of the nervous system. This type of attack behavior may occur in the central or peripheral nervous system, and in the neuromuscular junction, resulting in neuronal damage, axonal injury, demyelination or destruction of the neuromuscular junction. While the neurological deficits of patients with ADNS have received significant research attention, the manifestation of depression tends to be ignored. In fact, depressive manifestation is common in ADNS and adds significant burden upon patients suffering from this disease. Here, we systematically reviewed the current literature to highlight the prevalence, etiology and influence of depressive manifestation in ADNS. Most autoimmune diseases of the nervous system are discussed in this paper, from multiple sclerosis, acute disseminated encephalomyelitis and autoimmune encephalitis to acute myelitis, neuromyelitis optica, Guillain-Barré syndrome and myasthenia gravis. Depressive symptoms usually develop as a comorbidity during the course of disease, but sometimes exist as a primary presentation of the disease. Psychosocial factors, long periods of disablement and chronic pain are the three most common causes of depressive symptoms in many chronic conditions, particularly in peripheral neuropathy. Furthermore, the higher prevalence of depressive symptoms in ADNS suggests that immunological dysregulation may contribute to the elevated morbidity of depression. Finally, structural lesions of the brain, and some medications for ADNS, are also thought to precipitate depressive states in ADNS

Optimizing Instruction Scheduling and Register Allocation for Register-File-Connected Clustered VLIW Architectures

Clustering has become a common trend in very long instruction words (VLIW) architecture to solve the problem of area, energy consumption, and design complexity. Register-file-connected clustered (RFCC) VLIW architecture uses the mechanism of global register file to accomplish the inter-cluster data communications, thus eliminating the performance and energy consumption penalty caused by explicit inter-cluster data move operations in traditional bus-connected clustered (BCC) VLIW architecture. However, the limit number of access ports to the global register file has become an issue which must be well addressed; otherwise the performance and energy consumption would be harmed. In this paper, we presented compiler optimization techniques for an RFCC VLIW architecture called Lily, which is designed for encryption systems. These techniques aim at optimizing performance and energy consumption for Lily architecture, through appropriate manipulation of the code generation process to maintain a better management of the accesses to the global register file. All the techniques have been implemented and evaluated. The result shows that our techniques can significantly reduce the penalty of performance and energy consumption due to access port limitation of global register file

Contact dermatitis caused by prevention measures during the COVID-19 pandemic: a narrative review

IntroductionDuring the outbreak of Coronavirus disease 2019 (COVID-19), health care workers wore personal protective equipment including masks, gloves and goggles for a long time. In order to reduce the transmission routes of the virus, public places were sprayed with disinfectant. Moreover, the body, hands and clothing were frequently disinfected and washed for hygiene purposes. Studies have shown that these practices could easily irritate the skin and damage the skin barrier. Long-term irritation or exposure to allergens may lead to the occurrence of contact dermatitis (CD).MethodsSubject headings were searched via the National Library of Medicine (PubMed) and web of science databases: COVID-19; contact dermatitis; adverse skin reaction; PPE; dermatitis; mask; glory; hand hygiene, disinfection; face shield; goggle; protect cloth. A total of 246 and 646 articles were retrieved from the two databases, respectively. 402 articles remained after removing duplicates. Reviews, non-English articles, articles that could not be accessed to read or did not conform to our topic were excluded. Finally, a total of 32 cross-sectional studies, 9 case reports and 2 randomized controlled trials were included.DiscussionThis article reviews reports of CD caused by various prevention and hygiene measures during the COVID-19 pandemic. The amount of skin damage caused by COVID-19 prevention measures could be decreased by improved education about skin management

Molecular doping enabled scalable blading of efficient hole-transport-layer-free perovskite solar cells

The efficiencies of perovskite solar cells (PSCs) are now reaching such consistently high levels that scalable manufacturing at low cost is becoming critical. However, this remains challenging due to the expensive hole-transporting materials usually employed, and difficulties associated with the scalable deposition of other functional layers. By simplifying the device architecture, hole-transport-layer-free PSCs with improved photovoltaic performance are fabricated via a scalable doctor-blading process. Molecular doping of halide perovskite films improved the conductivity of the films and their electronic contact with the conductive substrate, resulting in a reduced series resistance. It facilitates the extraction of photoexcited holes from perovskite directly to the conductive substrate. The bladed hole-transport-layerfree PSCs showed a stabilized power conversion efficiency above 20.0%. This work represents a significant step towards the scalable, cost-effective manufacturing of PSCs with both high performance and simple fabrication processes

Epicuticular wax of sweet sorghum influenced the microbial community and fermentation quality of silage

Epicuticular wax, as secondary metabolites (hydrophobic compounds) covering plant surface, plays important roles in protecting plants from abiotic and biotic stresses. However, whether these compounds will influence fermentation process of silage is still not clear. In this study, two sweet sorghum cultivars with varying epicuticular wax on sheath (bloom), Yajin 2 (YJ, less bloom), and Jintian (JT, dense bloom), were harvested at flowering and maturing stages, and ensiled with or without bloom, aiming to evaluate the effects of bloom on fermentation quality, feed nutrition and microbial community. The bloom was collected manually with de-waxed cotton and extracted with chloroform. The results showed that the bloom reduced the concentrations of water-soluble carbohydrate and crude protein of the two cultivars at both stages, reduced lactic acid (LA) for YJ at both stages and for JT at flowering stage, and increased LA for JT at mature stage. The α-diversity of bacterial communities of the silage fermentation with bloom was significantly lower than that without bloom. Bloom increased the abundance of Lactobacillus, reduced that of Bacillus and Weissella, and significant correlations were observed between fermentative qualities and bacterial abundances. However, decreased diversity of bacterial community and the contents of LA implied that shifts in bacterial community might exert negative effects on silage fermentation. Our results suggest that bloom wax could alter the microbial community composition of ensiled sweet sorghums, which thus influence the fermentation qualities

1-Deoxynojirimycin from Bacillus subtilis improves antioxidant and antibacterial activities of juvenile Yoshitomi tilapia

Background: Juvenile Yoshitomi tilapia is often infected by pathogens and results in low-level survival rate. Bacillus subtilis, as a probiotic, may have beneficial effects on Y. tilapia with compound 1-deoxynojirimycin (DNJ), which has antibacterial activities. The effects of dietary probiotic supplementation on Y. tilapias were evaluated. Results: Juvenile Y. tilapia was fed with B. subtilis for 56 d. Y. tilapia was infected by Aeromonas hydrophila and survival rate was compared. Dietary B. subtilis increased weight gain rate, specific growth, food conversion ratios and food intake rate of Y. tilapia. The diet improved the cumulative survival rate (CSR) of juvenile Y. tilapia when the concentration of B. subtilis was more than 2.05 7 1010 cfu/kg and CSR reached a maximum rate when the concentration of bacillus was 4.23 7 1010 (P < 0.05). Meanwhile, B. subtilis improved total antioxidant capacity (TAC), spleen index, the activities of serum lysozyme, alkaline phosphatase (ALP), superoxide dismutase (SOD) and catalase (CAT) (P b 0.05). In contrast, B. subtilis reduced serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA) and C3 complement (P < 0.05). DNJ was isolated from secondary metabolisms and proved to increase the levels of SOD, CAT and reduce the levels of AST, ALT and MDA at cell levels. After A. hydrophila infection, DNJ prevented the reduction in survival rate of Y. tilapia (P < 0.05). Conclusions: 1-Deoxynojirimycin from Bacillus subtilis can be used to improve the growth performance of juvenile Y. tilapia by affecting its antioxidant and antibacterial activities