Searching for space-time variations of the constants of Nature is a promising way to search for new physics beyond general relativity and the standard model motivated by unification theories and ...models of dark matter and dark energy. We propose a new way to search for a variation of the fine-structure constant using measurements of late-type evolved giant stars from the S star cluster orbiting the supermassive black hole in our Galactic Center. A measurement of the difference between distinct absorption lines (with different sensitivity to the fine structure constant) from a star leads to a direct estimate of a variation of the fine structure constant between the star's location and Earth. Using spectroscopic measurements of five stars, we obtain a constraint on the relative variation of the fine structure constant below 10^{-5}. This is the first time a varying constant of nature is searched for around a black hole and in a high gravitational potential. This analysis shows new ways the monitoring of stars in the Galactic Center can be used to probe fundamental physics.
A novel MIMO sharp band-notched antenna with high isolation for UWB applications is presented. The antenna consists of two antenna elements with an overall area of 18 × 36 mm2. A T-shaped stub is ...extruded in the ground plane to improve isolation and an L-shaped stub to introduce band-notched function C-band (3.62–4.77 GHz). The designed antenna possesses a low mutual coupling of <−20 dB over the operating band from 2.9 to 20 GHz. The performance of this antenna is studied in terms of isolation between the two ports, radiation pattern, efficiency, realised gain, and envelope correlation coefficient.
The tracking of power in solar PV systems depends on controlling the voltage or current to the optimum level irrespective of changes in solar irradiation. There are two aspects of maximum power point ...tracking (MPPT), first is to control the voltage or current and second is to find the peak power with an algorithm. This work deals with both the aspects, using current control which provides fast control response and a momentum-based MPPT algorithm for improved peak tracking. Since current programmed control gives a simple implementation and fast response of converters, it would seem obvious to link it with current referenced MPPT but this method is prone to fail when irradiation drops suddenly, leading to control loss. Voltage oriented MPPT control (which has logarithmic dependance on irradiation), with an inner current control loop is used, as it maintains control even with step changes in irradiation. The second part of this work discusses the perturb and observe (hill climbing) algorithm for finding the power peak, which is known for its simple and effective implementation. A simple modification of this algorithm by adding momentum to the hill climbing is shown to improve the speed of tracking while maintaining the oscillations around maximum power point to acceptable levels.
Reactive arthritis (ReA) is typically preceded by sexually transmitted disease or gastrointestinal infection. An association has also been reported with bacterial and viral respiratory infections. ...Herein, we report the first case of ReA after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This male patient is in his 50s who was admitted with COVID-19 pneumonia. On the second day of admission, SARS-CoV-2 PCR was positive from nasopharyngeal swab specimen. Despite starting standard dose of favipiravir, his respiratory condition deteriorated during hospitalisation. On the fourth hospital day, he developed acute respiratory distress syndrome and was intubated. On day 11, he was successfully extubated, subsequently completing a 14-day course of favipiravir. On day 21, 1 day after starting physical therapy, he developed acute bilateral arthritis in his ankles, with mild enthesitis in his right Achilles tendon, without rash, conjunctivitis, or preceding diarrhoea or urethritis. Arthrocentesis of his left ankle revealed mild inflammatory fluid without monosodium urate or calcium pyrophosphate crystals. Culture of synovial fluid was negative. Plain X-rays of his ankles and feet showed no erosive changes or enthesophytes. Tests for syphilis, HIV, anti-streptolysin O (ASO), Mycoplasma, Chlamydia pneumoniae, antinuclear antibody, rheumatoid factor, anticyclic citrullinated peptide antibody and Human Leukocyte Antigen-B27 (HLA-B27) were negative. Gonococcal and Chlamydia trachomatis urine PCR were also negative. He was diagnosed with ReA. Nonsteroidal Anti-Inflammatory Drug (NSAID)s and intra-articular corticosteroid injection resulted in moderate improvement.
Atomically precise tailoring of graphene can enable unusual transport pathways and new nanometer-scale functional devices. Here we describe a recipe for the controlled production of highly regular ..."5-5-8" line defects in graphene by means of simultaneous electron irradiation and Joule heating by applied electric current. High-resolution transmission electron microscopy reveals individual steps of the growth process. Extending earlier theoretical work suggesting valley-discriminating capabilities of a graphene 5-5-8 line defect, we perform first-principles calculations of transport and find a strong energy dependence of valley polarization of the charge carriers across the defect. These findings inspire us to propose a compact electrostatically gated "valley valve" device, a critical component for valleytronics.
Antibody tests are used as surveillance tools for informing health policy making. However, results may vary by type of antibody assay and timing of sample collection following infection. Long-term ...longitudinal cohort studies on antibody assay seropositivity have remained limited, especially among Asian populations. Using blood samples obtained at health physicals (2020-2022) of healthcare workers (mass vaccinated with mRNA COVID-19 vaccines) at a Japanese medical center, we measured N-specific antibodies using two commercially available systems. Roche Elecsys Anti-SARS-CoV-2 measures total antibodies and Abbott Alinity SARS-CoV-2 IgG measures only IgG. Among 2538 participants, seroprevalence was found to be 16.6% via total antibody assay versus 12.9% by IgG-only (including grayzone) by mid-June 2022. For 219 cases with a previous PCR-confirmed infection, positivity was 97.3% using total antibody assay versus 76.3% using IgG-only assay at the 2022 health physical. Using PCR positive test date as day 0, while the positivity of the total antibody assay was retained for the entire study period (until more than 24-months post-infection), the IgG-only assay's positivity declined after month 4. The Mantel-Haenszel test found a significant difference in the two assays' seropositivity, between stratified groups of "within 3 months" and "4 months or more" from infection (P < 0.001). Our study found significant differences in seropositivity over time of total antibody versus IgG-only assays, suggesting an optimal assay for retaining sensitivity over the entire infection period when designing seroprevalence studies.
Clinical features of psoriatic arthritis Kishimoto, Mitsumasa; Deshpande, Gautam A.; Fukuoka, Kazuhito ...
Best practice & research. Clinical rheumatology,
06/2021, Letnik:
35, Številka:
2
Journal Article
Recenzirano
Psoriatic arthritis (PsA) is associated with decreased quality of life. As delayed diagnosis may lead to progressive joint destruction and long-term disability, the key clinical features of PsA ...should be recognizable to a wide range of clinicians to facilitate early diagnosis. In addition to assessment and identification of skin and nail lesions, which occur in up to 85% of those with musculoskeletal manifestations, clinicians should be aware of both the peripheral and axial manifestations of musculoskeletal disease reviewed here. Peripheral joint diseases include polyarticular, oligoarticular, distal, and arthritis mutilans subtypes, and cognizance of these patterns of disease, as well as periarticular manifestations, including dactylitis and enthesitis, is useful for swift diagnosis of PsA. Axial psoriatic arthritis (axial PsA), also known as the spondylitis subtype, may be limited to the spine and sacroiliac joints, but may also affect peripheral structures. Meticulous history-taking and physical examination and familiarity with appropriate imaging studies are often necessary to distinguish axial-PsA from other differential diagnoses. Swift diagnosis and treatment are necessary to both control PsA disease and mitigate the risks of the many associate comorbidities that may accompany it.
Evidence of BNT126b2 vaccine effectiveness and breakthrough has been primarily demonstrated in populations outside of Asia; studies in the Western Pacific region are limited. Our retrospective cohort ...study assessed SARS-CoV-2 cases after vaccine rollout starting from mid-March 2021 at a tertiary hospital in Tokyo. Of 8,749 staff members, no fully vaccinated staff demonstrated confirmed infection, versus 19 cases in unvaccinated or partially vaccinated staff, by the end of June. Three breakthrough cases were identified in July, correlating with spread of delta variant in Tokyo. While our findings confirm the effectiveness of BNT162b2 vaccine in Asian populations, the presence of breakthrough cases despite strict infection control regulations suggest that ongoing public hygiene measures are required even after vaccination.
Background The number of sample cases of colonic diverticular hemorrhage treated with endoscopic band ligation (EBL) has been small to date. Objective To elucidate the safety and efficacy of EBL for ...colonic diverticular hemorrhage. Design Retrospective study. Setting General hospital. Patients A total of 29 patients with 31 colonic diverticula with stigmata of recent hemorrhage (SRH). Interventions Urgent colonoscopy was performed after bowel preparation. When diverticula with SRH were identified, marking with hemoclips was done near the diverticula. The endoscope was removed and reinserted after a band-ligator device was attached to the tip of endoscope. At first, EBL was attempted. In patients who could not be treated with EBL, epinephrine injection or endoscopic clipping was performed. Main Outcome Measurements Procedure time, rate of hemostasis and rebleeding, complications. Results The mean procedure time was 47 ± 19 minutes. EBL was successfully completed in 27 colonic diverticula (87%); except in 3 diverticula with a small orifice and large dome and 1 diverticula in which the orifice was too large. Early rebleeding after EBL occurred in 3 of 27 cases (11%). Although 2 cases of sigmoid rebleeding could be managed by repeat EBL or conservatively, right hemicolectomy was performed in 1 ascending diverticulum, in which the bleeding source was not identified on repeat colonoscopy. Scar formation at previously banded diverticula was identified in 7 of 11 patients who underwent follow-up colonoscopy. There were no complications after EBL in any of the patients. Limitations Retrospective study. Conclusions EBL is a safe and effective treatment for colonic diverticular hemorrhage, and colonic diverticula resolve after EBL.
PDF
