Simulation and implementation of photonic integrated circuits for the filtering and optical heterodyning of mode-locked comb-lines.

We present the simulation and implementation of a photonic integrated circuit (PIC) designed for the filtering and optical heterodyning of comb-lines generated by a 20.97 GHz mode-locked fiber ring laser emitting at the optical C-band. We compare simulations obtained for the coupling junction of the microrings in the PIC with the use of an analytic approach and the finite difference time-domain (FDTD) method. A PIC designed for fabrication with the Triplex asymmetric double-stripe (ADS) waveguides was demonstrated. Using the PIC, we demonstrated the optical heterodyning of pairs of comb-lines filtered by tunable microrings. The phase noise of beat signals located at 20.97 and 41.94 GHz was characterized. We provide a discussion on enhancing the RF power of the beat signals with the use of optical injection locking.

What influences stroke survivors with physical disabilities to be physically active? A qualitative study informed by the Theoretical Domains Framework.

BACKGROUND: Although the benefits of regular physical activity (PA) after stroke are well established, many stroke survivors do not achieve recommended PA levels. To date, studies exploring determinants to PA have not used a behaviour change theory and focused on stroke survivors with physical disabilities. As a precursor to an intervention development study, we aimed to use the Theoretical Domains Framework (TDF) to identify factors influencing PA in stroke survivors with physical disabilities in Singapore. METHODS: Between November 2021 and January 2022, we conducted interviews with 19 community-dwelling stroke survivors with a weak arm and/or leg. An interview guide based on the TDF was developed. We analysed the data deductively by coding interview transcripts into the theoretical domains of the TDF, and then inductively by generating themes and belief statements. To identify relevant TDF domains, we prioritised the domains based on the frequencies of the belief statements, presence of conflicting belief statements and evidence of strong belief statements. RESULTS: Eight of the 14 TDF domains were relevant, and included environmental context and resources, knowledge, social influences, emotion, reinforcement, behavioural regulation, skills and beliefs about capabilities. The lack of access, suitable equipment and skilled help often limited PA participation at public fitness spaces such as parks, gyms and swimming pools (environmental context and resources). While a few stroke survivors expressed that they had the skills to engage in regular PA, most expressed not knowing how much and how hard to work, which exercises to do, which equipment to use and how to adapt exercises and equipment (knowledge and skills). This often left them feeling afraid to try new activities or venture out to new places for fear of the unknown or adverse events (e.g., falls) (emotion). For some, doing the activities in a group encourage them to get out and engage in PA (social influences). CONCLUSIONS: In stroke survivors with physical disabilities, environmental context and resources had a significant influence on PA participation, and this often had a spill over effect into other domains. Our results inform a complex behaviour change intervention to improve PA after stroke, and has implications for intervention design for people with physical disabilities.

Modified maxillomandibular advancement surgery for the treatment of obstructive sleep apnoea: a scoping review.

Modified maxillomandibular advancement (MMMA) has been proposed as an alternative to the classic maxillomandibular advancement (MMA) in East and Southeast Asian populations in which bimaxillary protrusion is a prevalent trait. The key difference between MMMA and MMA is the inclusion of anterior segmental osteotomies to reduce the protrusion of the perioral region. The aim of this scoping review was to identify the variations in MMMA and treatment outcomes. A search was conducted in the PubMed, Embase, and Cochrane electronic databases for articles published up to January 2023. Ten articles were included in this review. Three variations of MMMA have been reported in the literature. Treatment outcomes have mostly been favourable for all of these variations. Mandibular advancement of >10 mm and a greater than 50% reduction in the apnoea-hypopnoea index (AHI) have been well reported. Improvements in other outcome measures, such as enlargement of the airway dimension on computed tomography and the Epworth Sleepiness Scale score, have also been shown. Despite additional surgical procedures, complications have been uncommon and mostly minor in nature. It is necessary to be cognizant of MMMA and its variations when providing sleep surgery for East and Southeast Asian patients, tailoring this to the patient's profile and needs.

Surgical treatment of nasopharyngeal cancer - a consensus recommendation from two Chinese associations.

BACKGROUND: Surgical treatment is playing an increasingly important role in the management of nasopharyngeal carcinoma (NPC). This consensus focuses on the indications for optimal surgery, and surgical methods in the whole process of treatment for NPC to provide a useful reference to assist these difficult clinical decisions. METHODOLOGY: A thorough review of available literature on NPC and surgery was conducted by the Association for the prevention and treatment of nasopharyngeal carcinoma in China, international exchange and promotion Association for medicine and healthcare, and the Committee on nasopharyngeal cancer of Guangdong provincial anticancer association. A set of questions and a preliminary draft guideline was circulated to a panel of 1096 experienced specialists on this disease for voting on controversial areas and comments. A refined second proposal, based on a summary of the initial voting and different opinions expressed, was recirculated to the experts in two authoritative medical science and technology academic groups in the prevention and treatment of NPC in China for review and reconsideration. RESULTS: The initial round of questions showed variations in clinical practice even among similar specialists, reflecting the lack of high-quality supporting data and resulting difficulties in formulating clinical decisions. Through exchange of comments and iterative revisions, recommendations with high-to-moderate agreement were formulated on general treatment strategies and details of surgery, including indications and surgical approaches. CONCLUSION: By standardizing the surgical indications and practice, we hope not only to improve the surgical outcomes, but also to highlight the key directions of future clinical research in the surgical management of NPC.

Reporting standard for describing first responder systems, smartphone alerting systems, and AED networks.

Standardized reporting of data is crucial for out-of-hospital cardiac arrest (OHCA) research. While the implementation of first responder systems dispatching volunteers to OHCA is encouraged, there is currently no uniform reporting standard for describing these systems. A steering committee established a literature search to identify experts in smartphone alerting systems. These international experts were invited to a conference held in Hinterzarten, Germany, with 40 researchers from 13 countries in attendance. Prior to the conference, participants submitted proposals for parameters to be included in the reporting standard. The conference comprised five workshops covering different aspects of smartphone alerting systems. Proposed parameters were discussed, clarified, and consensus was achieved using the Nominal Group Technique. Participants voted in a modified Delphi approach on including each category as a core or supplementary element in the reporting standard. Results were presented, and a writing group developed definitions for all categories and items, which were sent to participants for revision and final voting using LimeSurvey web-based software. The resulting reporting standard consists of 68 core items and 21 supplementary items grouped into five topics (first responder system, first responder network, technology/algorithm/strategies, reporting data, and automated external defibrillators (AED)). This proposed reporting standard generated by an expert opinion group fills the gap in describing first responder systems. Its adoption in future research will facilitate comparison of systems and research outcomes, enhancing the transfer of scientific findings to clinical practice.

Anti-hypertensive prescription practices in private hospitals in Malaysia: a prospective, non-interventional, observational study.

INTRODUCTION: In managing hypertension, monotherapy and sometimes a combination of more than one agent are used to achieve blood pressure (BP) control. The objective of this prospective, observational, multi-centre study was to assess the level of BP control in patients receiving one or more anti-hypertensive drugs in private medical centres in Malaysia according to the treatment regimens (monotherapy, free drug combinations and single pill combinations). MATERIALS AND METHODS: Data were collected through medical records and interview sessions with patients on current pharmacotherapy for hypertension management at baseline and 2-3 months later. Results are expressed as mean ± SD for continuous data and as frequencies and percentages for categorical data. RESULTS: Among 182 recruited patients, 89 (49%) achieved BP control by the end of the study. Majority (62/89) patients were on single-pill (monotherapy or SPC) antihypertensives. Majority (63/89) required more than two antihypertensives to achieve BP control. CONCLUSION: Both SPC and free drug combination antihypertensives reduced BPs, but physicians preferred SPC to improve BP control and increase treatment compliance.

Investigating causal relationships between genetically determined increased risk of attention-deficit/hyperactivity disorder (ADHD) and atopic dermatitis (AD): A Mendelian randomization analysis.

Atopic dermatitis (AD) is a chronic, inflammatory skin condition with a huge disease burden. Attention-deficit/hyperactivity disorder (ADHD) is often diagnosed in children, and is associated with symptoms of inattention, hyperactivity and impulsive behaviour. Observational studies have demonstrated associations between AD and ADHD. However, to date, there has been no formal assessment of causal relationship between the two. We aim to evaluate causal relationships between genetically increased risk of AD and ADHD using Mendelian randomization (MR) approach. Two-sample bi-directional MR was conducted to elucidate potential causal relationships between genetically increased risk of AD and ADHD, using the largest and most recent genome-wide association study datasets for AD and ADHD-EArly Genetics & Lifecourse Epidemiology AD consortium (21 399 cases and 95 464 controls) and Psychiatric Genomics Consortium (20 183 cases and 35 191 controls). Genetically determined increased risk of AD is not associated with ADHD based on genetic information: odds ratio (OR) of 1.02 (95% CI -0.93 to 1.11; p = 0.705). Similarly, genetic determined increased risk of ADHD is not associated with an increased risk of AD: OR of 0.90 (95% CI -0.76 to 1.07; p = 0.236). Horizontal pleiotropy was not observed from the MR-Egger intercept test (p = 0.328) Current MR analysis showed no causal relationship between genetically increased risk of AD and ADHD in either direction in individuals of European descent. Any observed associations between AD and ADHD in previous population studies could possibly be due to confounding lifestyle factors such as psychosocial stress and sleeping habits.

Significance of Hypofractionated Radiotherapy in Postoperative Irradiation for Breast Cancer: An Asian Multi-institutional Prospective Study.

AIMS: There is a need for the adequate distribution of healthcare resources in Southeast Asia. Many countries in the region have more patients with advanced breast cancer who are eligible for postmastectomy radiotherapy (PMRT). Therefore, it is critical that hypofractionated PMRT is effective in most of these patients. This study investigated the significance of postoperative hypofractionated radiotherapy in patients with breast cancer, including advanced breast cancer, in these countries. MATERIALS AND METHODS: Eighteen facilities in 10 Asian countries participated in this prospective, interventional, single-arm study. The study included two independent regimens: hypofractionated whole-breast irradiation (WBI) for patients who had undergone breast-conserving surgery and hypofractionated PMRT for patients who had undergone total mastectomy at a dose of 43.2 Gy in 16 fractions. In the hypofractionated WBI group, patients with high-grade factors received additional 8.1 Gy boost irradiation sessions for the tumour bed in three fractions. RESULTS: Between February 2013 and October 2019, 227 and 222 patients were enrolled in the hypofractionated WBI and hypofractionated PMRT groups, respectively. The median follow-up periods in the hypofractionated WBI and hypofractionated PMRT groups were 61 and 60 months, respectively. The 5-year locoregional control rates were 98.9% (95% confidence interval 97.4-100.0) and 96.3% (95% confidence interval 93.2-99.4) in the hypofractionated WBI and hypofractionated PMRT groups, respectively. Regarding adverse events, grade 3 acute dermatitis was observed in 2.2% and 4.9% of patients in the hypofractionated WBI and hypofractionated PMRT groups, respectively. However, no other adverse events were observed. CONCLUSION: Although further follow-up is required, hypofractionated radiotherapy regimens for postoperative patients with breast cancer in East and Southeast Asian countries are effective and safe. In particular, the proven efficacy of hypofractionated PMRT indicates that more patients with advanced breast cancer can receive appropriate care in these countries. Hypofractionated WBI and hypofractionated PMRT are reasonable approaches that can contain cancer care costs in these countries. Long-term observation is required to validate our findings.

Characterization of the optical-gain enhanced microwave-Q for a 20.97 GHz regeneratively mode-locked laser with a short ring-length.

By treating a regeneratively mode-locked laser with a short ring length of 5.85 m as a coupled optoelectronic (OE) RF oscillator, the microwave quality factor (Q R F ) of its ring-cavity was characterized with the phase-shift approach. Specifically, the phase shift in the OE feedback loop of the mode-locked laser was varied, and the corresponding frequency shift in the photodetected first harmonic of its emitted pulse train was measured. An optical-gain enhanced Q R F of  ∼5.8×104 was measured, which is an order of magnitude larger than the Q R F estimated for the same cavity before regenerative mode-locking. The experimental results were then compared with theoretical models developed to estimate the optical-gain enhanced Q R F of coupled OE oscillators.

Functional assessment of military aircrew applicants in a hypobaric chamber.

BACKGROUND: Aircrew are exposed to environmental pressure changes. In the Republic of Singapore Air Force (RSAF), applicants assessed to be at intermediate risk of otic barotrauma undergo a hypobaric chamber assessment ["trial of chamber" (TOC)] to functionally evaluate their suitability for military aircrew vocations. AIMS: To identify factors associated with TOC failure among applicants with otorhinolaryngological conditions. METHODS: All applicants to RSAF aircrew vocations who were assessed to be at intermediate risk of otic barotrauma over a 3-yr period were identified using the RSAF Aeromedical Centre's electronic database. Their medical records, as well as the TOC assessment records of the subset of applicants who underwent TOC, were reviewed for demographic data, clinical findings, and TOC outcomes. RESULTS: Of the 483 identified applicants, 374 (77%) had abnormal otoscopic findings, 103 (21%) had rhinitis symptoms, and 6 (1%) had previous ENT surgery. 123 (25%) underwent TOC, of which 20 (16%) failed. Holding other predictor variables constant, the odds of TOC failure increased by 0.79 per unit decrease in BMI (95% CI 0.63-0.99), and the odds of TOC failure increased by 0.93 per kg decrease in body weight (95% CI 0.87-1.00). An abnormal tympanogram was not a statistically significant predictor of TOC failure (OR 1.96, 95% CI 0.59-6.42). Of the 47 applicants who passed TOC and were eventually recruited, none subsequently developed otic barotrauma (mean follow-up, 3.3 yr ± 1.5 yr). CONCLUSIONS: Applicants with lower weight and BMI are more likely to develop otic barotrauma with environmental pressure change. Tympanometry cannot be reliably used to identify applicants who would more likely pass TOC.

Survey of Patient Knowledge and Awareness of "Sick Day Rules" in Rheumatology Patients on Long Term Glucocorticoid Therapy.

Aims Rheumatic disease (RMD) patients treated with long-term glucocorticoids (GC) are at risk of developing tertiary adrenal insufficiency. With this survey we aimed to assess the knowledge of RMD patients taking long-term glucocorticoid therapy regarding risk of adrenal insufficiency and understanding of the "steroid sick day rules". Methods RMD patients taking ≥2.5 mg prednisolone daily for ≥3 months were recruited from the Rheumatology outpatient department in Beaumont Hospital, Dublin. Patient knowledge and previous counselling of steroid sick day rules was determined using an 8-point questionnaire carried out face-to-face or via phone call. Results 51 RMD patients on GC therapy were recruited. 3/51 (5.9%) of patients reported that they had been counselled on the Sick Day Rules. 2/51 (3.9%) carried a steroid emergency card or MedicAlert bracelet. Few patients would increase their steroid dose appropriately in response to infection, vomiting or peri-procedure [14/51 (27.5%); 9/51 (17.7%) and 5/51 (7.2%), respectively]. Conclusion We demonstrate a significant deficit of patient knowledge around the precautions for long-term GC use in rheumatic diseases. We suspect that our results may be generalisable to many other RMD units. We are currently reviewing our procedures around healthcare professional and patient education, issuing of information leaflets, emergency cards or MedicAlert bracelets etc. to at risk patients.

Correlations of tumour permeability parameters with apparent diffusion coefficient in nasopharyngeal carcinoma.

Background and Purpose: Functional imaging has an established role in therapeutic monitoring of cancer treatments. This study evaluated the correlations of tumour permeability parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and tumour cellularity derived from apparent diffusion coefficient (ADC) in nasopharyngeal carcinoma (NPC). Material and Methods: Twenty NPC patients were examined with DCE-MRI and RESOLVE diffusion-weighted MRI (DW-MRI). Tumour permeability parameters were quantitatively measured with Tofts compartment model. Volume transfer constant (Ktrans), volume of extravascular extracellular space (EES) per unit volume of tissue (Ve), and the flux rate constant between EES and plasma (Kep) from DCE-MRI scan were measured. The time-intensity curve was plotted from the 60 dynamic phases of DCE-MRI. The initial area under the curve for the first 60 s of the contrast agent arrival (iAUC60) was also calculated. They were compared with the ADC value derived from DW-MRI with Pearson correlation analyses. Results: Among the DCE-MRI permeability parameters, Kep had higher linearity in inverse correlation with ADC value (r = -0.69, p = <0.05). Ktrans (r = -0.60, p=<0.05) and iAUC60 (r = -0.64, p = <0.05) also had significant inverse correlations with ADC. Ve showed a significant positive correlation with ADC (r = 0.63, p = <0.05). Conclusions: Nasopharyngeal tumour vascular permeability parameters derived from DCE-MRI scan were correlated linearly with tumour cellularity measured by free water diffusability with ADC. The clinical implementations of these linear correlations in the quantitative assessments of therapeutic response for NPC patients may be worth to further explore.

Systematic review and meta-analysis of external ventricular drain placement accuracy and narrative review of guidance devices.

BACKGROUND: Insertion of external ventricular drain (EVD) is one of the most common neurosurgical procedures performed worldwide. This is generally performed freehand, on the basis of anatomical landmarks. There is significant variability in the reported accuracy of freehand placement, lacking Level I evidence. We present the first meta-analysis of freehand EVD placement accuracy and technologies or techniques to enhance accuracy. METHODS: We report a systematic review of the Pubmed, Embase, and Cochrane Central databases according to MOOSE (Meta-analysis Of Observational Studies) guidelines. 37 studies were included for qualitative analysis and 19 studies (2983 cases) for quantitative analysis. RESULTS: There is substantial heterogeneity in the outcome measures used to report EVD placement accuracy. Of those nineteen studies reporting accuracy using the Kakarla grading system the mean rate of ideal ipsilateral frontal horn placement was 73% (standard deviation ±7%). The use of formal stereotaxic guidance is consistently reported to improve accuracy to >90%, although with variable outcome measures. However, the reported efficacy of other guidance devices or techniques is highly variable. The quality of studies directly comparing all existing non-stereotaxic devices with freehand EVD placement is poor and precludes any assertion of superiority to freehand insertion. CONCLUSIONS: We provide the first meta analysis of freehand placement accuracy. There is insufficient data to perform a meta-analysis of the relative efficacy of interventions to improve accuracy. Qualitative synthesis of reports of stereotaxic guidance is suggestive of higher accuracy than freehand placement.