Fabrication and characterization of silicon nanowire FETs with coupled dopants induced quantum dot

Few dopants silicon transistor has been increasingly proposed in recent years, which provides a platform to understand the MOSFET scaling issues like threshold voltage shift, device performance non-consistent and dopant distribution fluctuations. The single and few dopants localized in silicon field effect transistor (FET) channel could also be used as the quantum dot (QD) for the single electron transistor (SET), which leads to an alternative way to achieve the quantum devices against the traditional method like structurally defined quantum dot. The modern fabrication technology like ion implantation and STM provide a more accurate method to define the single dopants in channel. However, the complex fabrication process makes these methods not practical. To overcome this technique challenge, Moraru and Tabe proposed the new fabrication method with spin-on dopants and selective doping to form the dopants cluster as a quantum dot. The study of the few dopants transistor also establishes the possibility for the future transistor with molecular and atomic scale. In this work, I introduce two generations of silicon nanowire FETs (NW-FETs) with different device designs and fabrication processes with silicon on insulator (SOI) platform. The innovation introduced is the nanowire design with notch structure. The nanowire notch structure helps to confine the dopants without thinning the silicon layer to be sub5 nm, which reduces the complexity of fabrication process but increases the tolerance. The aim of these two generations is to develop the few dopants transistor with spin-on dopants. The rapid thermal annealing (RTA) is used for the first device batch. As for the second generation, the thermal diffusion is applied to form the clustered dopants and provide sufficient current flow at low temperature. The silicon dioxide is used as the doping mask in both experiments. The commercial device simulator software Silvaco is first used to prove the suitability of the NW-FET device design. Through the fabrication, hundreds of NW-FETs with various doping configurations are fabricated in parallel. Different Ebeam resist HSQ and ZEP are used successfully to transfer the nanowire design and the smallest width of nanowire after dry etch is around 50 nm. For the first device generation, different NW-FETs with various device dimensions and doping configurations are measured. The short-channel effects are obtained from I-V characteristics including drain induced barrier lowing (DIBL) and gate induced drain leakage (GIDL) effects. By comparing the I-V performances of different devices at room temperature, the narrower and shorter the channel will contribute higher output current. However, the issue of the dopants freeze-out at low temperature make the device to be only measurable until 100K. By analysing the feedbacks of the first generation device, both device design and fabrication process are upgraded for the second generation. The new spin-on dopants solution with higher concentration is used with the thermal diffusion method, which increases the doping concentration at source and drain. By comparing the device with intrinsic and doped channel, the difference between threshold voltage is analysed to be corresponding to the channel doping of approximate 5 × 1018 cm−3 . The QD Coulomb oscillation and Coulomb diamonds characteristics obtained at 5K indicate single electron tunnelling through localized QD. Through the analysis of the characteristics of QD, the formation of QD is due to the confined dopants under top gate are strongly coupled. The number of dopants in QD is estimated to be 4-5. Through the temperature dependent measurement, the electron transport follows the Mott variable hopping mechanism. The hopping distance is found to be 6.7 nm and the critical temperature is calculated to be 57K, which is consistent with the Arrhenius plot. In a conclusion, the combination of thermally diffused spin-on dopants and notched nanowire successfully create the few dopants silicon NW-FET with clustered dopants. The standardized fabrication process is also established during the project. Through different measurements and analysis, the nature of QD is proved to be localized dopants deliberately doped selectively<br/

Research on Optical Fiber Sensor for Environmental Temperature and Humidity of Transmission Line

The operation environment of the transmission line directly affects the operation safety of the transmission line. This article studied a FBG temperature and humidity sensor based on optical fiber sensing technology for transmission lines. Firstly, this paper studies the packaging method of the sensor, then designs the corresponding installation fixture, and gives its installation diagram. Finally, the performance of the FBG is tested in the experimental box and the national optoelectronic information product quality supervision and inspection center, and the test results show that the performance of the FBG temperature and humidity sensor is better

Comparison of Intravenous versus Topical Tranexamic Acid in Nondeformity Spine Surgery: A Meta-Analysis

Objective. Tranexamic acid (TXA), an antifibrinolytic agent, interferes with fibrinolysis and has been used for many years to reduce blood loss during spine surgery. The purpose of our meta-analysis was to compare the effect of intravenous versus topical administration of TXA in patients undergoing nondeformity spine surgery. Methods. We searched multiple databases, including PubMed, Embase, the Cochrane library, CNKI, WanFang database, and VIP to find studies that met the inclusion criteria. A meta-analysis was performed according to the guidelines of the Cochrane Reviewer’s Handbook. Results. Eight randomized controlled trials (RCTs) were identified, including 660 patients. The surgical methods used in the included studies were nondeformity spine surgery. No significant differences were found in the two groups regarding total blood loss, intraoperative blood loss, hidden blood loss, hematocrit, hemoglobin, fibrinogen, postoperative prothrombin time (PT), postoperative activated partial thromboplastin time (APTT), drainage volume, and blood transfusion rate. There were statistically significant differences in the two groups in terms of preoperative PT (MD = −0.39, 95% CI: [−0.63, −0.15], P=0.002) and preoperative APTT (MD = 1.12, 95% CI: [0.57, 1.68], P<0.0001). Conclusion. During nondeformity spine surgery, intravenous administration of TXA did not have a significant effect on the decrease of blood loss and blood transfusion rate compared with the topical group. According to the pooled analysis of PT and APTT, intravenous and topical application of TXA may have different effects on the coagulation pathway. More high-quality RCTs are needed to explore the optimal dosage, method, timing in the future in order to recommend TXA widespread use in spine surgery

Efficacy and Safety of Modified Duhuo Jisheng Decoction in the Treatment of Lumbar Disc Herniation: A Systematic Review and Meta-Analysis

Objective. Lumbar disc herniation (LDH) is based on the degenerative changes of the intervertebral disc. Many drugs are used to treat and prevent LDH, including Western medicine and Chinese medicine. Duhuo Jisheng Decoction (DHJSD) is one of the most classic Chinese medicine prescriptions. The purpose of our meta-analysis is to evaluate the efficacy and safety of modified DHJSD in the treatment of LDH. Methods. We searched multiple databases including PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI) databases, Wanfang Database, and Chinese Scientific Journal Database (VIP) to identify studies that met the inclusion criteria. This meta-analysis was registered at INPLASY with reference number ID: INPLASY202060053. Results. Fourteen randomized controlled trials (RCTs) were identified, including 1560 patients. This meta-analysis showed that the total effective rate and cure rate of modified DHJSD are higher than those of diclofenac sodium enteric-coated tablets (total effective rate: RR = 1.18, 95% CI: 1.12 to 1.25, P<0.0001, I2 = 0%; cure rate: RR = 1.60, 95% CI: 1.30 to 1.97, P<0.00001, I2 = 2%), diclofenac sodium enteric-coated tablets plus ibuprofen and indomethacin (total effective rate: RR = 1.23, 95% CI: 1.11 to 1.37, P=0.0001, I2 = 0%; cure rate: RR = 1.58, 95% CI: 1.22 to 2.04, P=0.0005, I2 = 0%), and diclofenac sodium sustained-release capsule (total effective rate: RR = 1.49, 95% CI: 1.27 to 1.74, P<0.00001, I2 = 0%; cure rate: RR = 10.07, 95% CI: 3.29 to 30.88, P<0.00001, I2 = 5%). Modified DHJSD was also better than Western medicine (MD = −1.56, 95% CI: −2.42 to −0.70, P=0.0004, I2 = 74%) in terms of visual analogue scale (VAS) scores. Three RCTs showed no adverse events in the modified DHJSD group, but adverse events existed in the Western medicine group. Conclusion. This meta-analysis showed that modified DHJSD had a more favorable effect on the treatment of LDH than Western medicine, and there were no obvious adverse events. More high-quality RCTs are needed to complement existing conclusions

Efficacy and safety of perioperative use of non-steroidal anti-inflammatory drugs for preemptive analgesia in lumbar spine surgery: a systematic review and meta-analysis

Abstract Objective Lumbar spine disorders have become an increasingly common health problem in recent years. Modern clinical studies have shown that perioperative analgesia at certain doses can reduce postoperative pain by inhibiting the process of peripheral sensitization and central sensitization, which is also known as “preemptive analgesia,” Non-steroidal anti-inflammatory drugs (NSAIDs) are a class of drugs that achieve antipyretic and analgesic effects by inhibiting cyclooxygenase (COX) and affecting the production of prostaglandins. Our meta-analysis aimed to assess the efficacy and safety of perioperative preemptive analgesia with non-steroidal anti-inflammatory drugs in patients with lumbar spine surgery. Methods We searched PubMed, ScienceDirect, the Cochrane Library, and the Web of Science for randomized controlled trials (RCTs) that met the inclusion criteria. A total of 12 clinical studies were included to assess the efficacy and safety of perioperative NSAIDs preemptive analgesia for lumbar spine surgery. Result Twelve studies, including 845 patients, met the inclusion criteria. The results showed that perioperative receipt of NSAIDs for preemptive analgesia was effective and safe. Patient’s postoperative morphine consumption (P 0.05). Conclusion Our findings suggest that NSAIDs are effective and safe for preemptive analgesia in the perioperative period of lumbar spine surgery and that more and better quality RCTs and more in-depth studies of pain mechanics are still needed

Is coronal imbalance in degenerative lumbar scoliosis patients associated with the number of degenerated discs? A retrospective imaging cross-sectional study

Abstract Background Degenerative lumbar scoliosis (DLS) is a common degenerative disease of the spine, that predominates in the elderly, and causes spinal deformities along with severe pain and reduced quality of life. The relationship between DLS and degenerated discs is now a new direction of research. Our study aimed to the relationship between the imaging parameters of coronal imbalance and the number of degenerated discs in patients with degenerative lumbar scoliosis and analyzed the segmental distribution of the degenerated discs in patients with DLS. Methods We performed a retrospective analysis of the imaging of 40 patients who met the inclusion criteria who attended our outpatient clinic between April 2021 and July 2021, measuring the intervertebral space height of the AV (high side and low side), Cobb angle, and AVT (Apical vertebral translation) from coronal X-ray. Degenerated discs were evaluated by the Pfirrmann score based on T2-weighted magnetic resonance images. We record the number of degenerated discs (Graded as Grade III, Grade IV or Grade V by the Pfirrmann score) and the segments in which they are located. Finally, we explore the relationship between the imaging parameters of coronal imbalance and the number of degenerated discs in patients with DLS. Result Among the 40 patients with DLS in our study, all patients had degenerated discs in the lumbar spine, 95% of patients had degenerated discs(Pfirrmann score Grade III, Grade IV or Grade V) in 2 or more segments, with the L4-L5 segment being the most involved segment with the most degenerated discs, followed by the L3-L4 segment and the L5-S1 segment. There was no statistically significant relationship between the number of degenerated discs and the coronal imbalance in patients with DLS. Conclusion Our results showed an association between DLS and degenerated discs, but there was no statistically significant relationship between imbalance in the coronal plane of the lumbar spine and the number of degenerated discs in patients with DLS. The distribution of degenerated disc segments in patients with DLS showed a higher likelihood of disc degeneration in 2 or more segments, and a higher frequency of disc degeneration in the inferior disc and in the adjacent segments of the AV

Distribution of Two HIV-1–Resistant Polymorphisms (SDF1-30A and CCR2-64I) in East Asian and World Populations and Its Implication in AIDS Epidemiology

Chemokine receptor CCR2 and stromal-derived factor (SDF-1) are involved in HIV infection and AIDS symptom onset. Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3′A, can delay AIDS onset ⩾16 years after seroconversions. The protective effect of CCR2-64I is dominant, whereas that of SDF1-3′A is recessive. SDF1-3′A homozygotes also showed possible protection against HIV-1 infection. In this study, we surveyed the frequency distributions of the two alleles at both loci in world populations, with emphasis on those in east Asia. The CCR2-64I frequencies do not vary significantly in the different continents, having a range of 0.1–0.2 in most populations. A decreasing cline of the CCR2-64I frequency from north to south was observed in east Asia. In contrast, the distribution of SDF1-3′A in world populations varies substantially, and the highest frequency was observed in Oceanian populations. Moreover, an increasing cline of the SDF1-3′A frequency from north to south was observed in east Asia. The relative hazard values were computed to evaluate the risk of AIDS onset on the basis of two-locus genotypes in the east Asian and world populations