Delivery of nanosecond laser pulses by multi-mode anti-resonant hollow core fiber at 1†µm wavelength.

In this paper we explore the application of low-loss multimode anti-resonant hollow-core fiber (MM-AR-HCF) in the delivery of nanosecond laser pulses at 1 µm wavelength. MM-AR-HCF with large core offers a rich content of low-loss higher-order modes which plays a key role in the efficient coupling and transmission of high-power laser of low beam quality. In the experiment, laser pulses of an average pulse energy of 21.8 mJ with 14.6 ns pulse width (corresponding a peak power of 1.49 MW) are transmitted through MM-AR-HCF of 9.8 m length without damage. 85% transmission efficiency is achieved where the incident laser beam suffers a low beam quality with M2 x and M2 y of 2.18 and 1.99 respectively. Laser-induced damage threshold (LIDT) of MM-AR-HCF was measured to be 22.6 mJ for 85% transmission efficiency, which is 7 times higher than that for a multimode silica optical fiber with a large core of 200 µm.

Guidance of ultraviolet light down to 190 nm in a hollow-core optical fibre.

We report an anti-resonant hollow core fibre with ultraviolet transmission down to 190 nm, covering the entire UV-A, UV-B and much of the UV-C band. Guidance from 190 - 400 nm is achieved apart for a narrow high loss resonance band at 245 - 265 nm. The minimum attenuation is 0.13 dB/m at 235 nm and 0.16 dB/m at 325 nm. With an inscribed core diameter of ∼12 µm, the fibre's bend loss at 325 nm was 0.22 dB per turn for a bend radius of 3 cm at 325 nm.

Superiority and cost-effectiveness of Individual Placement and Support versus standard employment support for people with alcohol and drug dependence: a pragmatic, parallel-group, open-label, multicentre, randomised, controlled, phase 3 trial.

Background: Individual Placement and Support (IPS) is a specialist intervention to help people attain employment in the open competitive labour market. IPS has been developed in severe mental illness and other disabilities, but it is of unknown effectiveness for people with alcohol and drug dependence. The Individual Placement and Support-Alcohol and Drug (IPS-AD) is the first superiority trial to evaluate effectiveness and cost-effectiveness. Methods: IPS-AD was a pragmatic, parallel-group, multi-centre, randomised, controlled, phase 3 trial of standard employment support (treatment-as-usual [TAU]) versus IPS. IPS was offered as a single episode for up to 13 months. The study was done at seven community treatment centres for alcohol and drug dependence in England. Study participants were adults (18-65 years), who had been enrolled for at least 14 days in treatment for alcohol use disorder (AUD), opioid use disorder (OUD), or another drug use disorder (DUD; mostly cannabis and stimulants); were unemployed or economically inactive for at least six months; and wished to attain employment in the open competitive labour market. After random allocation to study interventions, the primary outcome was employment during 18-months of follow-up, analysed by mixed-effects logistic regression, using multiple imputation for the management of missing outcome data. There were two cost-effectiveness outcomes: a health outcome expressed as a quality adjusted life year (QALY) using £30,000 and £70,000 willingness-to-pay [WTP] thresholds; and additional days of employment, with a WTP threshold of £200 per day worked. The study was registered with ISRCTN (ISRCTN24159790) and is completed. Findings: Between 8 May 2018 and 30 September 2019, 2781 potentially eligible patients were identified. 812 were excluded before screening, and 1720 participants were randomly allocated to TAU or IPS. In error, nine participants were randomised to study interventions on two occasions-so data for their first randomisation was analysed (modified intention-to-treat). A further 24 participants withdrew consent for all data to be used (full-analysis set therefore 1687 participants [70.1% male; mean age 40.8 years]; TAU, n = 844; IPS, n = 843 [AUD, n = 610; OUD, n = 837; DUD, n = 240]). Standard employment support was received by 559 [66.2%] of 844 participants in the TAU group. IPS was received by 804 [95.37%] of 843 participants in the IPS group. IPS was associated with an increase in attainment of employment compared with TAU (adjusted odds ratio [OR] 1.29; 95% CI 1.02-1.64; p-value 0.036). IPS was effective for the AUD and DUD groups (OR 1.48; 95% CI 1.14-1.92; p-value 0.004; OR 1.45, 95% CI 1.03-2.04, p-value 0.031, respectively), but not the OUD group. IPS returned an incremental QALY outcome gain of 0.01 (range 0.003-0.02) per participant with no evidence of cost-effectiveness at either WTP threshold-but QALY gains were cost-effective for the AUD and DUD groups at the £70,000 WTP threshold (probability 0.52 and 0.97, respectively). IPS was cost-effective for additional days of employment (probability 0.61), with effectiveness relating to the AUD group only (probability >0.99). Serious Adverse Events were reported by 39 participants (13 [1.5%] of 844 participants in the TAU group and 23 [2.7%] of 43 participants in the IPS group). There was a total of 25 deaths (1.5%; 9 in the TAU group and 16 in the IPS group)-none judged related to study interventions. Interpretation: In this first superiority randomised controlled trial of IPS in alcohol and drug dependence, IPS helped more people attain employment in the open competitive labour market than standard employment support. IPS was cost-effective for a QALY health outcome (£70,000 WTP threshold) for the AUD and DUD groups, and for additional days of employment for the AUD group (£200 per day worked WTP threshold). Funding: UK government Work and Health Unit.

Low-loss multi-mode anti-resonant hollow-core fibers.

In this work, multi-mode anti-resonant hollow-core fiber (AR-HCF) with 18 fan-shaped resonators is fabricated and characterized. The ratio of core diameter over transmitted wavelengths in the lowest transmission band is up to 85. The measured attenuation at 1 µm wavelength is below 0.1 dB/m and the bend loss below 0.2 dB/m at a bend radius smaller than 8 cm. Modal content of the multi-mode AR-HCF is characterized using the S2 imaging technique and seven LP-like modes in total are identified using a 23.6 meter fiber length. Multi-mode AR-HCFs for longer wavelengths are fabricated by scaling up the same design, extending the transmission window beyond 4 µm wavelength. Low-loss multi-mode AR-HCF could find applications in the delivery of high-power laser light with a medium beam quality, where higher coupling efficiency and laser damage threshold are expected.

Generation and characterization of frequency tunable sub-15-fs pulses in a gas-filled hollow-core fiber pumped by a Yb:KGW laser.

We investigate soliton self-compression and photoionization effects in an argon-filled antiresonant hollow-core photonic crystal fiber pumped with a commercial Yb:KGW laser. Before the onset of photoionization, we demonstrate self-compression of our 220 fs pump laser to 13 fs in a single and compact stage. By using the plasma driven soliton self-frequency blueshift, we also demonstrate a tunable source from 1030 to ∼700 nm. We fully characterize the compressed pulses using sum-frequency generation time-domain ptychography, experimentally revealing the full time-frequency plasma-soliton dynamics in hollow-core fiber for the first time.

Measurement of resonant bend loss in anti-resonant hollow core optical fiber: erratum.

An error on the part of the authors in drafting resulted in Eq. (3) being incorrect in the published paper [Opt. Express25, 20612 (2017)10.1364/OE.25.020612]. We present a corrected version of the equation. It should be noted that this does not affect the presented results or conclusions of the paper.

Mechanical Behavior of Laminated Glass Polymer Interlayer Subjected to Environmental Effects.

It is known that weathering action has a significant impact on polymer interlayer materials, and previous studies have evaluated certain aspects of weathering such as temperature, humidity, and UV radiation. In this paper, the environmental effect on the mechanical properties of the virgin and cured/processed polymer interlayer materials will be studied. Three polymer interlayer materials were focused, i.e., Polyvinyl butyral (PVB), Ethylene-vinyl acetate (EVA), and Ionomer (SG), due to their industrial interest. Testing setups were designed to apply the environmental effects and perform mechanical testing on the polymeric materials. Four environmental effects were studied, including water submersion (E1), constant high temperature (E2), cyclic temperature with low relative humidity (E3), cyclic temperature, and relative humidity (E4). After the exposure of these materials to these environmental effects, the samples were prepared and mechanically tested. Uniaxial tests were performed under static and high strain rates (around 45-1). It was found that under dynamic load, the properties of EVA such as the strength, maximum strain, and the toughness were not significantly affected by the environmental effects. SG5000 properties were significantly affected.

Temperature-Dependent Group Delay of Photonic-Bandgap Hollow-Core Fiber Tuned by Surface-Mode Coupling.

Surface modes (SM) are highly spatially localized modes existing at the core-cladding interface of photonic-bandgap hollow-core fiber (PBG-HCF). When coupling with SM, the air modes (AM) in the core would suffer a higher confinement loss despite being spectrally within the cladding photonic bandgap, and would be highly dispersive around the avoided crossing (anti-crossing) wavelength. In this paper, we numerically explored how such avoided crossings can play an important role in the tuning of the temperature dependence of group delay of AM of PBG-HCF. At higher temperatures, both the thermo-optic effect and thermal expansion contribute to the redshift of avoided crossing wavelength, giving rise to a temperature dependence of the AM dispersion. Numerical simulations show that the redshift of avoided crossing can significantly tune the thermal coefficient of delay (TCD) of PBG-HCF from -400 ps/km/K to 400 ps/km/K, approximately -120 ppm/K to 120 ppm/K. In comparison with the known tuning mechanism by thermal-induced redshift of photonic bandgap [Fokoua et al., Optica 4, 659, 2017], the tuning of TCD by SM coupling presents a much broader tuning range and higher efficiency. Our finding may provide a new route to design PBG-HCF for propagation time sensitive applications.

Fabrication of Microchannels in a Nodeless Antiresonant Hollow-Core Fiber Using Femtosecond Laser Pulses.

In this work, we present femtosecond laser cutting of microchannels in a nodeless antiresonant hollow-core fiber (ARHCF). Due to its ability to guide light in an air core combined with exceptional light-guiding properties, an ARHCF with a relatively non-complex structure has a high application potential for laser-based gas detection. To improve the gas flow into the fiber core, a series of 250 × 30 µm microchannels were reproducibly fabricated in the outer cladding of the ARHCF directly above the gap between the cladding capillaries using a femtosecond laser. The execution time of a single lateral cut for optimal process parameters was 7 min. It has been experimentally shown that the implementation of 25 microchannels introduces low transmission losses of 0.17 dB (<0.01 dB per single microchannel). The flexibility of the process in terms of the length of the performed microchannel was experimentally demonstrated, which confirms the usefulness of the proposed method. Furthermore, the performed experiments have indicated that the maximum bending radius for the ARHCF, with the processed 100 µm long microchannel that did not introduce its breaking, is 15 cm.

Student-Authored Scientist Spotlights: Investigating the Impacts of Engaging Undergraduates as Developers of Inclusive Curriculum through a Service-Learning Course.

Scientist Spotlights-curricular materials that employ the personal and professional stories of scientists from diverse backgrounds-have previously been shown to positively influence undergraduate students' relatability to and perceptions of scientists. We hypothesized that engaging students in authoring Scientist Spotlights might produce curricular materials of similar impact, as well as provide a mechanism for student involvement as partners in science education reform. To test this idea and investigate the impact of student-authored Scientist Spotlights, we developed a service-learning course in which teams of biology students partnered with an instructor to develop and implement Scientist Spotlights in a biology course. Results revealed that exposure to three or four student-authored Scientist Spotlights significantly shifted peers' perceptions of scientists in all partner courses. Interestingly, student-authored Scientist Spotlights shifted peers' relatability to scientists similarly among both white students and students of color. Further, student authors themselves showed increases in their relatability to scientists. Finally, a department-wide survey demonstrated significant differences in students' perceptions of scientist representation between courses with and without student-authored Spotlights. Results suggest that engaging students as authors of inclusive curricular materials and partners in reform is a promising approach to promoting inclusion and addressing representation in science.

Delivery of CW laser power up to 300 watts at 1080†nm by an uncooled low-loss anti-resonant hollow-core fiber.

In this paper, we report the use of a 3-meter low-loss anti-resonant hollow-core fiber (AR-HCF) to deliver up to 300 W continuous-wave laser power at 1080 nm wavelength from a commercial fiber laser source. A near-diffraction-limited beam is measured at the output of the AR-HCF and no damage to the uncooled AR-HCF is observed for several hours of laser delivery operation. The limit of AR-HCF coupling efficiency and laser-induced thermal effects that were observed in our experiment are also discussed.

Molecular detection of Gram-positive bacteria in the human lung through an optical fiber-based endoscope.

PURPOSE: The relentless rise in antimicrobial resistance is a major societal challenge and requires, as part of its solution, a better understanding of bacterial colonization and infection. To facilitate this, we developed a highly efficient no-wash red optical molecular imaging agent that enables the rapid, selective, and specific visualization of Gram-positive bacteria through a bespoke optical fiber-based delivery/imaging endoscopic device. METHODS: We rationally designed a no-wash, red, Gram-positive-specific molecular imaging agent (Merocy-Van) based on vancomycin and an environmental merocyanine dye. We demonstrated the specificity and utility of the imaging agent in escalating in vitro and ex vivo whole human lung models (n = 3), utilizing a bespoke fiber-based delivery and imaging device, coupled to a wide-field, two-color endomicroscopy system. RESULTS: The imaging agent (Merocy-Van) was specific to Gram-positive bacteria and enabled no-wash imaging of S. aureus within the alveolar space of whole ex vivo human lungs within 60 s of delivery into the field-of-view, using the novel imaging/delivery endomicroscopy device. CONCLUSION: This platform enables the rapid and specific detection of Gram-positive bacteria in the human lung.

National administrative record linkage between specialist community drug and alcohol treatment data (the National Drug Treatment Monitoring System (NDTMS)) and inpatient hospitalisation data (Hospital Episode Statistics (HES)) in England: design, method and evaluation.

OBJECTIVES: The creation and evaluation of a national record linkage between substance misuse treatment, and inpatient hospitalisation data in England. DESIGN: A deterministic record linkage using personal identifiers to link the National Drug Treatment Monitoring System (NDTMS) curated by Public Health England (PHE), and Hospital Episode Statistics (HES) Admitted Patient Care curated by National Health Service (NHS) Digital. SETTING AND PARTICIPANTS: Adults accessing substance misuse treatment in England between 1 April 2018 and 31 March 2019 (n=268 251) were linked to inpatient hospitalisation records available since 1 April 1997. OUTCOME MEASURES: Using a gold-standard subset, linked using NHS number, we report the overall linkage sensitivity and precision. Predictors for linkage error were identified, and inverse probability weighting was used to interrogate any potential impact on the analysis of length of hospital stay. RESULTS: 79.7% (n=213 814) people were linked to at least one HES record, with an estimated overall sensitivity of between 82.5% and 83.3%, and a precision of between 90.3% and 96.4%. Individuals were more likely to link if they were women, white and aged between 46 and 60. Linked individuals were more likely to have an average length of hospital stay ≥5 days if they were men, older, had no fixed residential address or had problematic opioid use. These associations did not change substantially after probability weighting, suggesting they were not affected by bias from linkage error. CONCLUSIONS: Linkage between substance misuse treatment and hospitalisation records offers a powerful new tool to evaluate the impact of treatment on substance related harm in England. While linkage error can produce misleading results, linkage bias appears to have little effect on the association between substance misuse treatment and length of hospital admission. As subsequent analyses are conducted, potential biases associated with the linkage process should be considered in the interpretation of any findings.

Antiresonant Hollow-Core Fiber-Based Dual Gas Sensor for Detection of Methane and Carbon Dioxide in the Near- and Mid-Infrared Regions.

In this work, we present for the first time a laser-based dual gas sensor utilizing a silica-based Antiresonant Hollow-Core Fiber (ARHCF) operating in the Near- and Mid-Infrared spectral region. A 1-m-long fiber with an 84-µm diameter air-core was implemented as a low-volume absorption cell in a sensor configuration utilizing the simple and well-known Wavelength Modulation Spectroscopy (WMS) method. The fiber was filled with a mixture of methane (CH4) and carbon dioxide (CO2), and a simultaneous detection of both gases was demonstrated targeting their transitions at 3.334 µm and 1.574 µm, respectively. Due to excellent guidance properties of the fiber and low background noise, the proposed sensor reached a detection limit down to 24 parts-per-billion by volume for CH4 and 144 parts-per-million by volume for CO2. The obtained results confirm the suitability of ARHCF for efficient use in gas sensing applications for over a broad spectral range. Thanks to the demonstrated low loss, such fibers with lengths of over one meter can be used for increasing the laser-gas molecules interaction path, substituting bulk optics-based multipass cells, while delivering required flexibility, compactness, reliability and enhancement in the sensor's sensitivity.

Protocol for a multi-centre, definitive randomised controlled trial of the effectiveness of Individual Placement and Support for employment support among people with alcohol and drug dependence.

BACKGROUND: Unemployment is highly prevalent in populations with alcohol and drug dependence and the employment support offered in addiction-treatment programmes is ineffective. Individual Placement and Support (IPS) is an evidence-based intervention for competitive employment. IPS has been extensively studied in severe mental illness and physical disabilities, but there have been no formal randomised controlled trials (RCTs) in alcohol and drug dependence. The Individual Placement and Support for Alcohol and Drug Dependence (IPS-AD) study should determine whether IPS for patients with alcohol use disorder (AUD), opioid use disorder (OUD) and other drug use disorder is effective. DESIGN/METHODS: The IPS-AD study is a seven-site, pragmatic, two-arm, parallel-group, superiority RCT. IPS-AD includes a realist process evaluation. Eligible patients (adult, unemployed or economically inactive for at least 6 months and wishing to obtain open job market employment and enrolled in ongoing community treatment-as-usual (TAU; the control condition) in England for AUD, OUD and other drug use disorders) will be randomised (1:1) to receive TAU and any standard employment support, or TAU plus IPS (the experimental condition) for 9 months with up to 4 months of in-work support. The primary outcome measure will be competitive employment status (at least 1 day (7 h)) during an 18-month follow-up, determined by patient-level, trial-data-linkage with national tax and state benefit databases. From meta-analysis, an 18% target difference on this measure of vocational effectiveness (for the experimental intervention) and a two-sided 5% level of statistical significance, will require a minimum target sample of 832 participants to achieve 90% power for a pre-registered, mixed-effects, multi-variable logistic regression model. A maximum-likelihood multiple-imputation approach will manage missing outcome data. IPS-AD has six vocational secondary outcome measures during the 18-month follow-up: (1) total time in competitive employment (and corresponding National Insurance contributions and tax paid); (2) time from randomisation to first competitive employment; (3) number of competitive job appointments; (4) job tenure (length of longest held competitive employment); (5) sustained employment (tenure in a single appointment for at least 13 weeks); and (6) job search self-efficacy. A primary cost-benefit analysis and a secondary cost-effectiveness analysis will be done using the primary outcome and secondary vocational outcomes, respectively and will include addiction treatment and social and health outcomes and their associated reference costs. The process evaluation will address IPS implementation and delivery. DISCUSSION: The IPS-AD study is the first large-scale, multi-site, definitive, superiority RCT of IPS for people with alcohol and drug dependence. Findings from the study will have substantial implications for service delivery. TRIAL REGISTRATION: ISRCTN Registry, ID: ISRCTN24159790. Registered on 1 February 2018.

Medicines associated with dependence or withdrawal: a mixed-methods public health review and national database study in England.

BACKGROUND: Antidepressants, opioids for non-cancer pain, gabapentinoids (gabapentin and pregabalin), benzodiazepines, and Z-drugs (zopiclone, zaleplon, and zolpidem) are commonly prescribed medicine classes associated with a risk of dependence or withdrawal. We aimed to review the evidence for these harms and estimate the prevalence of dispensed prescriptions, their geographical distribution, and duration of continuous receipt using all patient-linked prescription data in England. METHODS: This was a mixed-methods public health review, comprising a rapid evidence assessment of articles (Jan 1, 2008, to Oct 3, 2018; with searches of MEDLINE, Embase, and PsycINFO, and the Cochrane and King's Fund libraries), an open call-for-evidence on patient experience and service evaluations, and a retrospective, patient-linked analysis of the National Health Service (NHS) Business Services Authority prescription database (April 1, 2015, to March 30, 2018) for all adults aged 18 years and over. Indirectly (sex and age) standardised rates (ISRs) were computed for all 195 NHS Clinical Commissioning Groups in England, containing 7821 general practices for the geographical analysis. We used publicly available mid-year (June 30) data on the resident adult population and investigated deprivation using the English Indices of Multiple Deprivation (IMD) quintiles (quintile 1 least deprived, quintile 5 most deprived), with each patient assigned to the IMD quintile score of their general practitioner's practice for each year. Statistical modelling (adjusted incident rate ratios [IRRs]) of the number of patients who had a prescription dispensed for each medicine class, and the number of patients in receipt of a prescription for at least 12 months, was done by sex, age group, and IMD quintile. FINDINGS: 77 articles on the five medicine classes were identified from the literature search and call-for-evidence. 17 randomised placebo-controlled trials (6729 participants) reported antidepressant-associated withdrawal symptoms. Almost all studies were rated of very low, low, or moderate quality. The focus of qualitative and other reports was on patients' experiences of long-term antidepressant use, and typically sudden onset, severe, and protracted withdrawal symptoms when medication was stopped. Between April 1, 2017, and March 31, 2018, 11·53 million individuals (26·3% of residents in England) had a prescription dispensed for at least one medicine class: antidepressants (7·26 million [16·6%]), opioids (5·61 million [12·8%]), gabapentinoids (1·46 million [3·3%]), benzodiazepines (1·35 million [3·1%]), and Z-drugs (0·99 million [2·3%]). For three of these medicine classes, more people had a prescription dispensed in areas of higher deprivation, with adjusted IRRs (referenced to quintile 1) ranging from 1·10 to 1·24 for antidepressants, 1·20 to 1·85 for opioids, and 1·21 to 1·85 for gabapentinoids across quintiles, and higher ISRs generally concentrated in the north and east of England. In contrast, the highest ISRs for benzodiazepines and Z-drugs were generally in the southwest, southeast, and east of England, with low ISRs in the north. Z-drugs were associated with increased deprivation, but only at the highest quintile (adjusted IRR 1·11 [95% CI 1·01-1·22]). For benzodiazepines, prescribing was reduced for people in quintiles 4 (0·90 [0·85-0·96]) and 5 (0·89 [0·82-0·97]). In March, 2018, for each of medicine class, about 50% of patients who had a prescription dispensed had done so continuously for at least 12 months, with the highest ISRs in the north and east. Long-term prescribing was associated with a gradient of increased deprivation. INTERPRETATION: In 1 year over a quarter of the adult population in England had a prescription dispensed for antidepressants, opioids (for non-cancer pain), gabapentinoids, benzodiazepines, or Z-drugs. Long-term (>12 months) prescribing is common, despite being either not recommended by clinical guidelines or of doubtful efficacy in many cases. Enhanced national and local monitoring, better guidance for personalised care, and better doctor-patient decision making are needed. FUNDING: Public Health England.

Investigating Instructor Talk in Novel Contexts: Widespread Use, Unexpected Categories, and an Emergent Sampling Strategy.

Instructor Talk-noncontent language used by instructors in classrooms-is a recently defined and promising variable for better understanding classroom dynamics. Having previously characterized the Instructor Talk framework within the context of a single course, we present here our results surrounding the applicability of the Instructor Talk framework to noncontent language used by instructors in novel course contexts. We analyzed Instructor Talk in eight additional biology courses in their entirety and in 61 biology courses using an emergent sampling strategy. We observed widespread use of Instructor Talk with variation in the amount and category type used. The vast majority of Instructor Talk could be characterized using the originally published Instructor Talk framework, suggesting the robustness of this framework. Additionally, a new form of Instructor Talk-Negatively Phrased Instructor Talk, language that may discourage students or distract from the learning process-was detected in these novel course contexts. Finally, the emergent sampling strategy described here may allow investigation of Instructor Talk in even larger numbers of courses across institutions and disciplines. Given its widespread use, potential influence on students in learning environments, and ability to be sampled, Instructor Talk may be a key variable to consider in future research on teaching and learning in higher education.

Ultra-low background Raman sensing using a negative-curvature fibre and no distal optics.

Measuring Raman spectra through an optical fibre is usually complicated by the high intrinsic Raman scatter of the fibre material. Common solutions such as the use of multiple fibres and distal optics are complex and bulky. We demonstrate the use of single novel hollow-core negative-curvature fibres (NCFs) for Raman and surface-enhanced Raman spectroscopy (SERS) sensing using no distal optics. The background Raman emission from the silica in the NCF was at least 1000× smaller than in a conventional solid fibre, while maintaining the same collection efficiency. We transmitted pump light from a 785-nm laser through the NCF, and we collected back the weak Raman spectra of different distal samples, demonstrating the fibre probe can be used for measurements of weak Raman and SERS signals that would otherwise overlap spectrally with the silica background. The lack of distal optics and consequent small probe diameter (<0.25 mm) enable applications that were not previously possible.

Single-mode solarization-free hollow-core fiber for ultraviolet pulse delivery.

In this paper, we report anti-resonant silica hollow-core fibers (AR-HCFs) for solarization-free ultraviolet (UV) pulse transmission. The new fibers reported have lower attenuation than any previous HCFs for this spectral range. We report a single fiber that guides over a part of the UV-C and the whole of the UV-A spectral regions in adjacent transmission bands. A second AR-HCF is used for delivery of 17 nanosecond laser pulses at 266 nm at 30 kHz repetition rate. The fiber maintained a constant transmission, free of silica fluorescence and solarization-induced fiber degradation while delivering 0.46 µJ pulses for a period of over one hour. By direct comparison, we demonstrate that the single-mode AR-HCF significantly outperforms commercially-available high-OH and solarization-resistant silica multimode fibers for pulsed light delivery in this spectral range.

Effectiveness of inpatient withdrawal and residential rehabilitation interventions for alcohol use disorder: A national observational, cohort study in England.

BACKGROUND: This was a national English observational cohort study to estimate the effectiveness of inpatient withdrawal (IW) and residential rehabilitation (RR) interventions for alcohol use disorder (AUD) using administrative data. METHODS: All adults commencing IW and/or RR intervention for AUD between April 1, 2014 and March 31, 2015 reported to the National Drug Treatment Monitoring System (n=3812). The primary outcome was successful completion of treatment within 12months of commencement, with no re-presentation (SCNR) in the subsequent six months, analysed by multi-level, mixed effects, multivariable logistic regression. RESULTS: The majority (70%, n=2682) received IW in their index treatment journey; one-quarter (24%, n=915) received RR; 6% (n=215) received both. Of treatment leavers, 59% achieved the SCNR outcome (IW: 57%; RR: 64%; IW/RR: 57%). Positive outcome for IW was associated with older age, being employed, and receiving community-based treatment prior to and subsequent to IW. Patients with housing problems were less likely to achieving the outcome. Positive outcome for RR was associated with paid employment, self/family/peer referral, longer duration of RR treatment, and community-based treatment following discharge. Community-based treatment prior to entering RR, and receiving IW during the same treatment journey as RR, were associated with lower likelihood of SCNR. CONCLUSIONS: In this first national effectiveness study of AUD in the English public treatment system for alcohol-use disorders, 59% of patients successfully completed treatment within 12months and did not represent for more treatment within six months. Longer duration of treatment and provision of structured continuing care is associated with better treatment outcomes.