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Abstract The key challenge for high-power delivery through optical fibers is overcoming nonlinear optical effects. To keep a smooth output beam, most techniques for mitigating optical nonlinearities are restricted to single-mode fibers. Moving out of the single-mode paradigm, we show experimentally that wavefront-shaping of coherent input light to a highly multimode fiber can increase the power threshold for stimulated Brillouin scattering (SBS) by an order of magnitude, whilst simultaneously controlling the output beam profile. The SBS suppression results from an effective broadening of the Brillouin spectrum under multimode excitation, without broadening of transmitted light. Strongest suppression is achieved with selective mode excitation that gives the broadest Brillouin spectrum. Our method is efficient, robust, and applicable to continuous waves and pulses. This work points toward a promising route for mitigating detrimental nonlinear effects in optical fibers, enabling further power scaling of high-power fiber systems for applications to directed energy, remote sensing, and gravitational-wave detection.

In order to overcome the limitations of traditional stochastic models for smartphones, we introduce a double-difference code pseudorange residual (DDPR)-dependent stochastic model based on an optimal satellite subset, with the goal of mitigating the constraints imposed by the quality of GNSS observations in smartphones on the accuracy and reliability of phone-based GNSS positioning. In our methodology, the satellite selection process involved considering the integrated carrier-to-noise density ratio (C/N0) index of both the reference station and the smartphone, enabling us to construct a satellite subset characterized by superior observation quality. Furthermore, by leveraging the optimal subset of satellites and incorporating the C/N0-dependent stochastic model, we could determine the approximate location of the terminal through pseudorange differential positioning. Subsequently, we estimated the DDPRs for all satellites and utilized these values as prior information to build a stochastic model of the observations. Our findings indicate that in occluded environments, the DDPR-dependent stochastic model significantly enhances positioning accuracy for both the Huawei Mate40 and P40 terminals compared to the C/N0-dependent model. Numerically, the improvements in the north (N), east (E), and up (U) directions were approximately 30%, 32%, and 34% for the Mate40, and 26%, 33%, and 24% for the P40 terminal. This suggests that the proposed DDPR-dependent stochastic model effectively identifies and mitigates large gross error signals caused by multipath and non-line-of-sight (NLOS) signals, thereby assigning lower weights to these problematic observations and ultimately enhancing positioning accuracy. Moreover, the weighting method involves minimal computations and is straightforward to implement, making it particularly suitable for GNSS positioning applications on smartphones in complex urban environments.

Fiber drawing from a 3D printed perform was recently discussed to go beyond the limitations of conventional optical fiber manufacturing in terms of structure and materials. In this work, the photosensitivity of silica optical fibers to femtosecond laser light, and fabricated by 3D printing a preform, is investigated. The writing kinetics and the thermal performance of Type II modifications are studied by varying the laser pulse energy and investigating the birefringence response of the femtosecond (fs)-laser written structures. Compared with a conventional telecom single mode fiber (SMF28), the fiber made by 3D printing is found to have similar writing kinetics and thermal performance. Additionally, the thermal stability of the imprinted fs-laser induced nanostructures is investigated based on the Rayleigh–Plesset equation, describing a model of nanopores dissolution underpinning Type II modifications with thermal annealing.

Water access, sanitation and hygiene (WASH) data for Malaysia suggest that almost 100% of the population have access to basic sanitation and basic drinking water, but this data may not include marginalised communities and stateless individuals, indigenous or otherwise. The aim of this study was to evaluate WASH provision for residents of the Johor River Basin and evaluate the disparity in facilities between indigenous Orang Asli and more modernised communities. Questionnaires were distributed to eight communities. In total, 899 questionnaires were completed including 100 from indigenous communities and 799 from more modernised communities. Significant differences existed between communities with regard to education levels (p < 0.001), occupation (p < 0.001), household income (p < 0.001), type of toilet, sewage and sanitation facilities (p < 0.001) and perception of health risks and concerns (p < 0.001). There is a significant difference in access to water and sanitation facilities between indigenous and modernised communities. Further study is now required to understand behaviours and educate river-based communities on relevant potential health risks from water contamination in the Johor River Basin. HIGHLIGHTS There is considerable disparity between indigenous and more modernised communities with respect to access to water, sanitation and hygiene facilities in the Johor River Basin, Malaysia.; Perceptions of health issues and WASH between indigenous and more modernised communities also exist.;

As in many low- and middle-income countries around the world, thousands of local communities in Southeast Asia rely on river water to sustain their livelihoods. However, poor water quality threatens the health of both humans and ecosystems. The aim of this review was to examine the available literature to investigate how health outcomes in Malaysia have been studied and reported as directly attributable to human infections from river water. Computer-aided searches from 10 electronic databases were undertaken, with searches limited to the English language and publication dates since January 2010. The literature search revealed that the predominant river water infections identified in Malaysia were bacterial (coliforms, Salmonella spp., typhoid, leptospirosis, melioidosis), viral (including dengue, hepatitis, enterovirus), parasitic infections including amoebiasis, giardiasis and cryptosporidiosis, helminth infections, Blastocystis infections and sarcocystosis. No studies were found that have attempted to evaluate the impact of water related infection on human health longitudinally. Moreover, the possibility of integrated water governance systems that could reduce infection and improve water quality, particularly for marginalized groups have not been discussed or studied. Several cross-sectional studies identified infections at a point in time, but large longitudinal data sets of water infection parameters and how they influence human health outcomes have not been reported. Using Malaysia as a demonstration case study, we suggest a number of recommendations based on using a systems approach to tackle the challenges involved in data collection and integration, which is central to the understanding, strategic planning and management of water-borne infections.

Introduction Air pollution and air quality are growing concerns among urban citizens of Southeast Asia, especially the University students who devote most of their days to the vicinity of campus. However, there is limited data available on the extent of the problem, as well as an understanding of the knowledge of and perceptions of people who may be exposed to poor air quality. Methods This focused study evaluated University students’ opinions, perceptions, and behavioral responses to local air quality in the Iskandar Puteri, Johor region of Malaysia using an online questionnaire, and measurements of NO2, SO2, formaldehyde, and particulate matter levels in the area using diffusion tubes. All air quality parameters were within the standards recommended by the local environmental authority, however, NO2 levels exceeded the recommended World Health Organization (WHO) standards at all sites. Results Questionnaire findings indicate that students most commonly suffered from respiratory diseases, and were very concerned about air pollution and its impacts. Respondents perceived the situation to be worse in the afternoons and weekends, corroborated by the PM2.5 readings in the area. Preferred preventive measures included wearing masks and limiting active time outdoors. Conclusions The evidence from this study highlighted the need to improve air quality in Iskandar Puteri as the NO2 level exceeded international standards for human health at all study sites. This could be supported by educational programs for industry, limitations on traffic emissions, and general awareness of air quality issues present locally. [ABSTRACT FROM AUTHOR]

Background The purpose of the present study was to evaluate efficacy and patient satisfaction of acupuncture or Chuna therapy for back pain. Methods Amongst all the patients with back pain who had been treated at Sun-cheon korean medicine hospital, Dong-shin university, only patients that had received either acupuncture or Chuna manual therapy between September 1 and October 31, 2017 were selected and their medical charts retrospectively analyzed. A questionnaire was used in the investigation that consisted of a numeric rating scale (NRS), the Oswestry low-back pain disability index (ODI), general, emotional, conversational, and technical satisfaction. The questionnaire was completed before treatment and at weekly intervals (approximately). Treatment efficacy was analyzed using the first and last questionnaires. The last questionnaire was also used to establish patient satisfaction. The data were analyzed using SPSS for Windows version 21.0. Results The NRS, Current degree of pain (ODI-1), and total ODI were significantly decreased in both the acupuncture and Chuna groups. The differences in NRS, ODI-1, and total ODI changes between treatment groups were not significant. There were no statistically significant differences between the acupuncture and Chuna groups in terms of general, emotional, conversational, and technical satisfaction. Conclusions Acupuncture treatment significantly reduces NRS and ODI in patients who have back pain without structural transformation, and Chuna therapy significantly reduces NRS and ODI-1 in patients who have back pain with structural transformation. These results indicate that further studies should be conducted in more patients and over a longer period.

Background This research was performed to investigate the effects of Pulsatilla Koreana NAKAI pharmacopuncture (PPA) therapy on intestinal disease in rats with dextran sulfate sodium (DSS)-induced colitis. Methods The subjects were divided into five groups : A control group, saline group, pharmacopuncture group PPA1 (0.2 ㎎/ 1 kg/ 40 ㎕), pharmacopuncture group PPA2 (0.5 ㎎/ 1 kg/ 40 ㎕), and pharmacopuncture group PPA 3(1 ㎎/ 1 kg/ 40 ㎕). The experimental model of colitis was induced by infection of dextran sulfate sodium (DSS) for eighteen days. After colitis was induced, PPA therapy was practiced on the Chunchu (ST25) once every two days for a total six times. Thereafter Disease Activity Index (DAI), colon length, damage to the colonic mucosa, body weight, IL-6, IL-10, IL-1β, IFN-γ, TNF-α, TGF-β1, IL-23 and IL-17 were measured. Results The results were as follows. 1. DAI was significantly decreased in the PPA groups. 2. Colon length was significantly increased in the PPA groups. 3. Damage of colonic mucosa was observed less in the PPA groups. 4. Body weight was significantly increased in the saline group and the PPA groups. 5. The PPA2 group showed a significant decrease in the intensity of IL-6, IL-1β, IFN-γand TNF-α levels and the mean of IL-23. 6. The PPA3 group showed a significant increase in the intensity of IL-10 and TGF-β1 levels. 7. No significant differences were shown in the mean of IL-17. Conclusions These results suggest that PPA therapy on Chunchu (ST25) can be used as an effective treatment for inflammatory bowel disease.