THz QCLs Design Toward Real Applications

For highly desired THz applications, we discuss the design and fabrication of THz quantum cascade lasers (QCLs) toward the high temperature and large average output power operations for the real applications with the relatively compact portable size cryogenic cooling systems. We describe the temperature performance parameters of THz QCLs and introduce the recent results of an indirect injection design scheme in the THz region and modulation height active structure design with different barriers and wells for the further design direction. The recent fabricated THz QCLs are combined with the liquid nitrogen (LN) cooling Dewar condenser to demonstrate the relatively compact THz source unit by QCLs. The different injection schemes in THz and barriers‐wells height design in the active region introduce one of the directions for the further high temperature and large output power operation of THz QCLs. The relatively compact size THz source unit with a cryogenic system demonstrates the THz QCLs for real applications with the milliwatt order average output operation near liquid nitrogen temperature

Fair Robust Active Learning by Joint Inconsistency

Fair Active Learning (FAL) utilized active learning techniques to achieve high model performance with limited data and to reach fairness between sensitive groups (e.g., genders). However, the impact of the adversarial attack, which is vital for various safety-critical machine learning applications, is not yet addressed in FAL. Observing this, we introduce a novel task, Fair Robust Active Learning (FRAL), integrating conventional FAL and adversarial robustness. FRAL requires ML models to leverage active learning techniques to jointly achieve equalized performance on benign data and equalized robustness against adversarial attacks between groups. In this new task, previous FAL methods generally face the problem of unbearable computational burden and ineffectiveness. Therefore, we develop a simple yet effective FRAL strategy by Joint INconsistency (JIN). To efficiently find samples that can boost the performance and robustness of disadvantaged groups for labeling, our method exploits the prediction inconsistency between benign and adversarial samples as well as between standard and robust models. Extensive experiments under diverse datasets and sensitive groups demonstrate that our method not only achieves fairer performance on benign samples but also obtains fairer robustness under white-box PGD attacks compared with existing active learning and FAL baselines. We are optimistic that FRAL would pave a new path for developing safe and robust ML research and applications such as facial attribute recognition in biometrics systems.Comment: 11 pages, 3 figure

Challenges of regulatory theory and practice : a study of hawker control in Hong Kong

published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

Reanalyze unassigned reads in Sanger based metagenomic data using conserved gene adjacency

<p>Abstract</p> <p>Background</p> <p>Investigation of metagenomes provides greater insight into uncultured microbial communities. The improvement in sequencing technology, which yields a large amount of sequence data, has led to major breakthroughs in the field. However, at present, taxonomic binning tools for metagenomes discard 30-40% of Sanger sequencing data due to the stringency of BLAST cut-offs. In an attempt to provide a comprehensive overview of metagenomic data, we re-analyzed the discarded metagenomes by using less stringent cut-offs. Additionally, we introduced a new criterion, namely, the evolutionary conservation of adjacency between neighboring genes. To evaluate the feasibility of our approach, we re-analyzed discarded contigs and singletons from several environments with different levels of complexity. We also compared the consistency between our taxonomic binning and those reported in the original studies.</p> <p>Results</p> <p>Among the discarded data, we found that 23.7 ± 3.9% of singletons and 14.1 ± 1.0% of contigs were assigned to taxa. The recovery rates for singletons were higher than those for contigs. The <it>Pearson </it>correlation coefficient revealed a high degree of similarity (0.94 ± 0.03 at the phylum rank and 0.80 ± 0.11 at the family rank) between the proposed taxonomic binning approach and those reported in original studies. In addition, an evaluation using simulated data demonstrated the reliability of the proposed approach.</p> <p>Conclusions</p> <p>Our findings suggest that taking account of conserved neighboring gene adjacency improves taxonomic assignment when analyzing metagenomes using Sanger sequencing. In other words, utilizing the conserved gene order as a criterion will reduce the amount of data discarded when analyzing metagenomes.</p

Evidence for formation of multi-quantum dots in hydrogenated graphene.

We report the experimental evidence for the formation of multi-quantum dots in a hydrogenated single-layer graphene flake. The existence of multi-quantum dots is supported by the low-temperature measurements on a field effect transistor structure device. The resulting Coulomb blockade diamonds shown in the color scale plot together with the number of Coulomb peaks exhibit the characteristics of the so-called 'stochastic Coulomb blockade'. A possible explanation for the formation of the multi-quantum dots, which is not observed in pristine graphene to date, was attributed to the impurities and defects unintentionally decorated on a single-layer graphene flake which was not treated with the thermal annealing process. Graphene multi-quantum dots developed around impurities and defect sites during the hydrogen plasma exposure process.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Evaluation of the new AJCC staging system for resectable hepatocellular carcinoma

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to assess the validity of the 7^thedition of the American Joint Committee on Cancer (AJCC) TNM system (TNM-7) for patients undergoing hepatectomy for hepatocellular carcinoma (HCC).</p> <p>Methods</p> <p>Partial hepatectomies performed for 879 patients from 1993 to 2005 were retrospectively reviewed. Clinicopathological factors, surgical outcome, overall survival (OS), and disease-free survival (DFS) were analyzed to evaluate the predictive value of the TNM-7 staging system.</p> <p>Results</p> <p>According to the TNM-7 system, differences in five-year survival between stages I, II, and III were statistically significant. Subgroup analysis of stage III patients revealed that the difference between stages II and IIIA was not significant (OS, <it>p </it>= 0.246; DFS, <it>p </it>= 0.105). Further stratification of stages IIIA, IIIB and IIIC also did not reveal significant differences. Cox proportional hazard models of stage III analyses identified additional clinicopathological factors affecting patient survival: lack of tumor encapsulation, aspartate aminotransferase (AST) values > 68 U/L, and blood loss > 500 mL affected DFS whereas lack of tumor encapsulation, AST values > 68 U/L, blood loss > 500 mL, and serum α-fetoprotein (AFP) values > 200 ng/mL were independent factors impairing OS. Stage III factors including tumor thrombus, satellite lesions, and tumor rupture did not appear to influence survival in the stage III subgroup.</p> <p>Conclusions</p> <p>In terms of 5-year survival rates, the TNM-7 system is capable of stratifying post-hepatectomy HCC patients into stages I, II, and III but is unable to stratify stage III patients into stages IIIA, IIIB and IIIC. Lack of tumor encapsulation, AST values > 68 U/L, blood loss > 500 mL, and AFP values > 200 ng/mL are independent prognostic factors affecting long-term survival.</p

Antimicrobial resistance of Moraxella catarrhalis isolates in Taiwan

Background/PurposeThe prevalence of ampicillin-resistant Moraxella catarrhalis has been higher in Taiwan than in other countries, with reports of 97.7% in the 1990s. The aims of this study were to assess resistance trends for M. catarrhalis, which causes respiratory tract infections, against several classes of oral antibiotics and to compare the minimum inhibitory concentration (MIC) of antimicrobial agents against M. catarrhalis isolates between 1993–1994 and 2001–2004.MethodsClinical isolates of M. catarrhalis (n = 314) were collected from 11 large medical centers in Taiwan between 2001 and 2004. β-Lactamase production tests were performed. The MICs for 13 different oral antibiotics were calculated using the agar dilution method. Pulsed-field gel electrophoresis (PFGE) was performed for 18 randomly selected high-level ampicillin-resistant (BRO-1 β-lactamase-positive, MIC ≥ 32 μg/mL) isolates to investigate their genetic relatedness.ResultsThe overall rate of β-lactamase-producing isolates was 97.8% (307/314). All isolates were susceptible to amoxicillin + clavulanate, chloramphenicol, cefixime, ciprofloxacin, erythromycin, levofloxacin, moxifloxacin, and roxithromycin. The rate of resistance to cefaclor and cefuroxime was 8.3% and 1.3%, respectively, while no resistance was found in 1993–1994. Resistance to trimethoprim–sulfamethoxazole (SXT) and tetracycline was 18.5% and 19.8%, respectively. Comparison of 1993–1994 and 2001–2004 isolates revealed that the zone diameter for amoxicillin + clavulanate disks decreased from 43 mm in 1993–1994 to 32 mm in 2001–2004 (p < 0.001). However, MIC50 (0.25 μg/mL in both 1993–1994 and 2001–2004) and MIC90 (0.5 μg/mL in both 1993–1994 and 2001–2004) for amoxicillin + clavulanate did not differ between the study periods. The PFGE typing results demonstrate that at least two closely related BRO-1 clones are spreading in Taiwan.ConclusionThe rates of resistance to cefaclor, cefuroxime, tetracycline and SXT are now increasing in Taiwan. Molecular typing showed that at least two closely related BRO-1 clones are circulating. Although amoxicillin + clavulanate remains the antimicrobial therapy of choice for M. catarrhalis infections, continued surveillance of antimicrobial susceptibility and application of control measures against further transmission are required to inhibit the emergence of the resistant strains

The 2021 flexible and printed electronics roadmap

This roadmap includes the perspectives and visions of leading researchers in the key areas of flexible and printable electronics. The covered topics are broadly organized by the device technologies (sections 1–9), fabrication techniques (sections 10–12), and design and modeling approaches (sections 13 and 14) essential to the future development of new applications leveraging flexible electronics (FE). The interdisciplinary nature of this field involves everything from fundamental scientific discoveries to engineering challenges; from design and synthesis of new materials via novel device design to modelling and digital manufacturing of integrated systems. As such, this roadmap aims to serve as a resource on the current status and future challenges in the areas covered by the roadmap and to highlight the breadth and wide-ranging opportunities made available by FE technologies

Controlled spatial separation of spins and coherent dynamics in spin-orbit-coupled nanostructures.

The spatial separation of electron spins followed by the control of their individual spin dynamics has recently emerged as an essential ingredient in many proposals for spin-based technologies because it would enable both of the two spin species to be simultaneously utilized, distinct from most of the current spintronic studies and technologies wherein only one spin species could be handled at a time. Here we demonstrate that the spatial spin splitting of a coherent beam of electrons can be achieved and controlled using the interplay between an external magnetic field and Rashba spin-orbit interaction in semiconductor nanostructures. The technique of transverse magnetic focusing is used to detect this spin separation. More notably, our ability to engineer the spin-orbit interactions enables us to simultaneously manipulate and probe the coherent spin dynamics of both spin species and hence their correlation, which could open a route towards spintronics and spin-based quantum information processing