bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanosecond laser pulse modulation using seed electrons from cascade ionization induced by inverse-Bremsstrahlung photon absorption
Authors: Park Youchan , Kim Kyeongsun , Kim Seonwoong , Carter Campbell D. , Do Hyungrok
Published: February 2022

Nanosecond (ns) laser pulses are modulated by seeding electrons on the laser beam path. The seed-electrons are from auxiliary ns-laser-induced breakdown (ALIB), and the ALIB is induced by a focused 1064-nm pulse, which is split after the frequency-doubling that generates the 532-nm pulse; therefore, the 532-nm and 1064-nm pulses are synchronized. The slowly converging (focal length = 500 mm) 532-nm pulse is re-directed to transmit through the region in where the ALIB-generated electrons reside. The seed-electrons from the ALIB then absorb the 532-nm photons via the inverse-Bremsstrahlung photon absorption (IBPA) process. The number density of the seed-electrons on the 532-nm beam path (ne,ALIB) is controlled by varying 1) the 532-nm pulse arrival time at the ALIB region (ΔPAT) after the 1064-nm pulse triggers the ALIB and 2) the location of the 532-nm beam relative to the core of the ALIB; the electron number density in ALIB is highly non-uniform and evolves in time. Electron-seeded laser-induced breakdown (ESLIB) occurs when ne,ALIB is sufficiently high. The 532-nm beam convergence (controlled by the focusing lens) is adjusted so that the breakdown does not occur without the electron seeding. The ESLIB immediately stops the transmission of the trailing edge of the laser pulse acting as a fast shutter, and ne,ALIB above a threshold can cut the pulse leading edge to modulate the 532-nm laser pulse.
Investigation of the lasing performance of a crystalline-coated Yb:YAG thin-disk directly bonded onto a silicon carbide heatsink
Authors: Cvrček Jan , Cimrman Martin , Vojna David , Štěpánková Denisa , Foršt Ondřej , Smrž Martin , Novák Ondřej , Slezák Ondřej , Chyla Michal , Jelínek Michal , Mocek Tomáš
Published: February 2022

We investigated the use of crystalline coatings as the highly reflective coating of an Yb:YAG thin disk directly bonded onto a silicon carbide heatsink. Compared to commonly used ion-beam-sputtered coatings, it possesses lower optical losses and higher thermal conductivity, resulting in better heat management and laser outputs. We pumped the disk up to 1.15 kW at 969 nm and reached 665 W of average output power, and disk temperature of 107 °C with a highly multi-modal V-cavity. These promising results were reached with this novel design despite the adoption of a cheap silicon carbide substrate having more than 3 times lower thermal conductivity compared to frequently used CVD diamond.
Generative-adversarial-network-based dimensional measurement of optical waveguides
Authors: Ota Masashi , Yamaguchi Keita , Suzuki Kenya
Published: February 2022

We propose a high-throughput and precise waveguide-dimensional-measurement method consisting of a generative adversarial network (GAN) and curve-fitting-based dimensional calculator using sidewall functions. The GAN can learn the differences between low-magnification (LM) and high-magnification (HM) optical microscope images taken with different objective lenses at different magnifications over the same area. The LM and HM images of the waveguides are captured using an optical microscope at magnifications of 500× and 2000×, respectively. We obtained a standard deviation of the waveguide widths of approximately 0.8 pixels (∼ 42 nm), and confirmed precise width measurement using super-resolution images at the same imaging throughput as with an LM microscope.
Deterministic distribution of multipartite entanglement in a quantum network by continuous-variable polarization states
Authors: Wu Liang , Chai Ting , Liu Yanhong , Zhou Yaoyao , Qin Jiliang , Yan Zhihui , Jia Xiaojun
Published: February 2022

Quantum network plays a vitally important role in the practical application of quantum information, which requires the deterministic entanglement distribution among multiple remote users. Here, we propose a feasible scheme to deterministically distribute quadripartite entanglement by continuous-variable (CV) polarization states. The quantum server prepares the quadripartite CV polarization entanglement and distributes them to four remote users via optical fiber. In this way, the measurement of CV polarization entanglement is local oscillation free, which makes the long distance entanglement distribution in commercial optical fiber communication networks possible. Furthermore, both the Greenberger-Horne-Zeilinger-like (GHZ-like) and cluster-like polarization entangled states can be distributed among four users by controlling the beam splitter network in quantum server, which are confirmed by the extended criteria for polarization entanglement of multipartite optical modes. The protocol provides the direct reference for experimental implementation and can be directly extended to quantum network with more users, which is essential for a metropolitan quantum network.
Observation of a highly superluminal laser employing optically pumped Raman gain and depletion
Authors: Zhou Zifan , Condon Nicholas , Hileman Devin , Shahriar M. S.
Published: February 2022

In this paper, we report a Raman laser which is extremely sensitive to a variation of the cavity length, using a scheme employing two stable isotopes of Rb. One isotope is used for producing a broad gain spectrum via the optically pumped Raman gain process, while the other is used for producing a narrow dip via the optically pumped Raman depletion process. By tuning the frequencies of the two Raman pumps, the center frequencies of the gain and dip can be aligned to the same frequency. This approach allows tuning of the gain and dip parameters independently over a broad range of operating conditions. With such a configuration, we can produce a negative dispersion around the two-photon resonance frequency in the vapor cell, which leads to a group index that is close to zero. By theoretically matching the experimental observations, we can infer that the sensitivity of such laser is enhanced by a factor of more than 2800, which is nearly a factor of three larger than the highest value reported previously using a different approach.
Long-haul intermodal-MIMO-free MDM transmission based on a weakly coupled multiple-ring-core few-mode fiber
Authors: Zuo Mingqing , Ge Dawei , Liu JiaXin , Gao Yuyang , Shen Lei , Lan Xiaobo , Chen Zhangyuan , He Yongqi , Li Juhao
Published: February 2022

Mode-division multiplexing (MDM) technique based on few-mode fibers (FMFs) can achieve multiplicative growth in single-fiber capacity by using different linearly polarized (LP) modes or mode groups as spatial channels. However, its deployment is seriously impeded because multiple-input multiple-output digital signal processing (MIMO-DSP) with huge computational load must be adopted to combat intermodal crosstalk for long-haul FMF transmission. In this paper, we present an intermodal-MIMO-free MDM transmission scheme based on weakly coupled multiple-ring-core FMF, which achieves ultralow distributed modal crosstalk (DMC) so that the signal in each LP mode can be independently received by single-LP-mode MIMO-DSP even after hundreds-of-kilometer transmission. Evaluation method for the required DMC levels is proposed and different transmission reaches are investigated by simulation. By adopting an improved method for quantitative DMC measurement, we show that the required DMC level for long-haul transmission is feasible. Finally, we experimentally demonstrate 1800-km LP01/LP02 multiplexed transmission and 525-km LP01/LP21/LP02 multiplexed transmission only adopting 2×2 or 4×4 MIMO-DSP. The proposed scheme may pave the way to practical applications of long-haul MDM techniques for the first time.
Hydrodynamics explanation for the splitting of higher-charge optical vortices
Authors: Voitiv Andrew A. , Andersen Jasmine M. , Ford Patrick C. , Lusk Mark T. , Siemens Mark E.
Published: February 2022

We show that a two-dimensional hydrodynamics model provides a physical explanation for the splitting of higher-charge optical vortices under elliptical deformations. The model is applicable to laser light and quantum fluids alike. The study delineates vortex breakups from vortex unions under different forms of asymmetry in the beam, and it is also applied to explain the motion of intact higher-charge vortices.
Resolving ambiguities of the mode truncation in cavity quantum electrodynamics
Authors: Taylor Michael A. D. , Mandal Arkajit , Huo Pengfei
Published: February 2022

This work provides the fundamental theoretical framework for few-mode
cavity quantum electrodynamics by resolving the gauge ambiguities
between the Coulomb gauge and the dipole gauge Hamiltonians under the
photonic mode truncation. We first propose a general framework to
resolve ambiguities for an arbitrary truncation in a given gauge.
Then, we specifically consider the case of mode truncation, deriving
gauge invariant expressions for both the Coulomb and dipole gauge
Hamiltonians that naturally reduce to the commonly used single-mode
Hamiltonians when considering a single-mode truncation. We finally
provide the analytical and numerical results of both atomic and
molecular model systems coupled to the cavity to demonstrate the
validity of our theory.
Ultrafast Mueller matrix polarimetry with 10 nanosecond temporal resolution based on optical time-stretch
Authors: Feng Yuanhua , Huang Jianwen , Zhou Ji , Gao Shecheng , Liu Weiping , Jiang Xiumei , Huang Shuqiang , Li Zhaohui
Published: February 2022

A fastest full Mueller matrix polarimeter, to the best of our knowledge, based on optical time-stretch has been proposed and demonstrated. Thanks to the time-stretch-based ultrafast spectra detection mechanism, its measurement time could reach 10 ns. Additionally, a novel, to the best of aour knowledge, simpler method to estimate its main systematic error has been proposed and verified. With the proposed method, static measurement of polarizer and wave plate is executed with a maximum coefficient error of below 0.1. Dynamic measurement of a free space electro-optic modulator as fast-changing phase retardation has also been executed to demonstrate the feasibility of the proposed system.
Deterministic generation of a perfect soliton crystal microcomb with a saturable absorber
Authors: Nakashima Ayata , Fujii Shun , Imamura Riku , Nagashima Keigo , Tanabe Takasumi
Published: February 2022

We numerically investigate the deterministic generation of a perfect soliton crystal (PSC) in an optical microresonator functionalized with a saturable absorber (SA). The SA allows the direct formation of a PSC from an initial, periodic Turing roll. It prevents passage through a chaotic state, which induces a stochastic nature with regard to the number of generated dissipative Kerr solitons. We show that PSCs form deterministically, and the number is controlled by adjusting the input power and SA parameter. Our work provides a simple approach for obtaining a stable PSC that offers an ultrahigh repetition rate and a high comb output power.
A cortical network processes auditory error signals during human speech production to maintain fluency
Authors: Ozker Muge , Doyle Werner , Devinsky Orrin , Flinker Adeen
Published: February 2022

Hearing one’s own voice is critical for fluent speech production as it allows for the detection and correction of vocalization errors in real time. This behavior known as the auditory feedback control of speech is impaired in various neurological disorders ranging from stuttering to aphasia; however, the underlying neural mechanisms are still poorly understood. Computational models of speech motor control suggest that, during speech production, the brain uses an efference copy of the motor command to generate an internal estimate of the speech output. When actual feedback differs from this internal estimate, an error signal is generated to correct the internal estimate and update necessary motor commands to produce intended speech. We were able to localize the auditory error signal using electrocorticographic recordings from neurosurgical participants during a delayed auditory feedback (DAF) paradigm. In this task, participants hear their voice with a time delay as they produced words and sentences (similar to an echo on a conference call), which is well known to disrupt fluency by causing slow and stutter-like speech in humans. We observed a significant response enhancement in auditory cortex that scaled with the duration of feedback delay, indicating an auditory speech error signal. Immediately following auditory cortex, dorsal precentral gyrus (dPreCG), a region that has not been implicated in auditory feedback processing before, exhibited a markedly similar response enhancement, suggesting a tight coupling between the 2 regions. Critically, response enhancement in dPreCG occurred only during articulation of long utterances due to a continuous mismatch between produced speech and reafferent feedback. These results suggest that dPreCG plays an essential role in processing auditory error signals during speech production to maintain fluency.
Integrated healthcare services for HIV, diabetes mellitus and hypertension in selected health facilities in Kampala and Wakiso districts, Uganda: A qualitative methods study
Authors: Bukenya Dominic , Van Hout Marie-Claire , Shayo Elizabeth H. , Kitabye Isaac , Junior Brian Musenze , Kasidi Joan Ritar , Birungi Josephine , Jaffar Shabbar , Seeley Janet
Published: February 2022

Health policies in Africa are shifting towards integrated care services for chronic conditions, but in parts of Africa robust evidence on effectiveness is limited. We assessed the integration of vertical health services for HIV, diabetes and hypertension provided in a feasibility study within five health facilities in Uganda. From November 2018 to January 2020, we conducted a series of three in-depth interviews with 31, 29 and 24 service users attending the integrated clinics within Kampala and Wakiso districts. Ten healthcare workers were interviewed twice during the same period. Interviews were conducted in Luganda, translated into English, and analysed thematically using the concepts of availability, affordability and acceptability. All participants reported shortages of diabetes and hypertension drugs and diagnostic equipment prior to the establishment of the integrated clinics. These shortages were mostly addressed in the integrated clinics through a drugs buffer. Integration did not affect the already good provision of anti-retroviral therapy. The cost of transport reduced because of fewer clinic visits after integration. Healthcare workers reported that the main cause of non-adherence among users with diabetes and hypertension was poverty. Participants with diabetes and hypertension reported they could not afford private clinical investigations or purchase drugs prior to the establishment of the integrated clinics. The strengthening of drug supply for non-communicable conditions in the integrated clinics was welcomed. Most participants observed that the integrated clinic reduced feelings of stigma for those living with HIV. Sharing the clinic afforded privacy about an individual’s condition, and users were comfortable with the waiting room sitting arrangement. We found that integrating non-communicable disease and HIV care had benefits for all users. Integrated care could be an effective model of care if service users have access to a reliable supply of basic medicines for both HIV and non-communicable disease conditions.
Low-level overexpression of wild type TDP-43 causes late-onset, progressive neurodegeneration and paralysis in mice
Authors: Yang Chunxing , Qiao Tao , Yu Jia , Wang Hongyan , Guo Yansu , Salameh Johnny , Metterville Jake , Parsi Sepideh , Yusuf Issa , Brown Robert H. , Cai Huaibin , Xu Zuoshang
Published: February 2022

Modestly increased expression of transactive response DNA binding protein (TDP-43) gene have been reported in amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neuromuscular diseases. However, whether this modest elevation triggers neurodegeneration is not known. Although high levels of TDP-43 overexpression have been modeled in mice and shown to cause early death, models with low-level overexpression that mimic the human condition have not been established. In this study, transgenic mice overexpressing wild type TDP-43 at less than 60% above the endogenous CNS levels were constructed, and their phenotypes analyzed by a variety of techniques, including biochemical, molecular, histological, behavioral techniques and electromyography. The TDP-43 transgene was expressed in neurons, astrocytes, and oligodendrocytes in the cortex and predominantly in astrocytes and oligodendrocytes in the spinal cord. The mice developed a reproducible progressive weakness ending in paralysis in mid-life. Detailed analysis showed ~30% loss of large pyramidal neurons in the layer V motor cortex; in the spinal cord, severe demyelination was accompanied by oligodendrocyte injury, protein aggregation, astrogliosis and microgliosis, and elevation of neuroinflammation. Surprisingly, there was no loss of lower motor neurons in the lumbar spinal cord despite the complete paralysis of the hindlimbs. However, denervation was detected at the neuromuscular junction. These results demonstrate that low-level TDP-43 overexpression can cause diverse aspects of ALS, including late-onset and progressive motor dysfunction, neuroinflammation, and neurodegeneration. Our findings suggest that persistent modest elevations in TDP-43 expression can lead to ALS and other neurological disorders involving TDP-43 proteinopathy. Because of the predictable and progressive clinical paralytic phenotype, this transgenic mouse model will be useful in preclinical trial of therapeutics targeting neurological disorders associated with elevated levels of TDP-43.
Market impact shapes competitive advantage of investment strategies in financial markets
Authors: Xu Wen-Juan , Zhong Li-Xin
Published: February 2022

The formation of an efficient market depends on the competition between different investment strategies, which accelerates all available information into asset prices. By incorporating market impact and two kinds of investment strategies into an agent-based model, we have investigated the coevolutionary mechanism of different investment strategies and the role of market impact in shaping a competitive advantage in financial markets. The coevolution of history-dependent strategies and reference point strategies depends on the levels of market impact and risk tolerance. For low market impact and low risk tolerance, the majority-win effect makes the trend-following strategies become dominant strategies. For high market impact and low risk tolerance, the minority-win effect makes the trend-rejecting strategies coupled with trend-following strategies become dominant strategies. The coupled effects of price fluctuations and strategy distributions have been investigated in depth. A U-shape distribution of history-dependent strategies is beneficial for a stable price, which is destroyed by the existence of reference point strategies with low risk tolerance. A δ-like distribution of history-dependent strategies leads to a large price fluctuation, which is suppressed by the existence of reference point strategies with high risk tolerance. The strategies that earn more in an inefficient market lose more in an efficient market. Such a result gives us another explanation for the principle of risk-profit equilibrium in financial markets: high return in an inefficient market should be coupled with high risk in an efficient market, low return in an inefficient market should be coupled with low risk in an efficient market.
Transient dynamics of infection transmission in a simulated intensive care unit
Authors: Jackson Katelin C. , Short Christopher T. , Toman Kellan R. , Mietchen Matthew S. , Lofgren Eric ,   for the CDC MInD-Healthcare Program
Published: February 2022

Healthcare-associated infections (HAIs) remain a serious public health problem. In previous work, two models of an intensive care unit (ICU) showed that differing population structures had markedly different rates of Staphylococcus aureus (MRSA) transmission. One explanation for this difference is the models having differing long-term equilbrium dynamics, resulting from different basic reproductive numbers, R0. We find in this system however that this is not the case, and that both models had the same value for R0. Instead, short-term, transient dynamics, characterizing a series of small, self-limiting outbreaks caused by pathogen reintroduction were responsible for the differences. These results show the importance of these short-term factors for disease systems where reintroduction events are frequent, even if they are below the epidemic threshold. Further, we examine how subtle changes in how a hospital is organized—or how a model assumes a hospital is organized—in terms of the admission of new patients may impact transmission rates. This has implications for both novel pathogens introduced into ICUs, such as Ebola, MERS or COVID-19, as well as existing healthcare-associated infections such as carbapenem-resistant Enterobacteriaceae.
Seasonal changes in the expression of insulin-like androgenic hormone (IAG) in the androgenic gland of the Jonah crab, Cancer borealis
Authors: Lawrence Amanda , Green Shadaesha , Wang Tao , Bachvaroff Tsvetan , Chung J. Sook
Published: February 2022

Harvesting the adult male Jonah crab, Cancer borealis, mainly based on the size, has become an economically significant fishery, particularly in the Southern New England region of the US since 2000. Many decapod crustacean fisheries including C. borealis rely on harvesting adult males. Understanding the size related-sexual maturity and the seasonal changes in male reproductive activity is critical for sustainable management. In other decapods, an insulin-like hormone produced by the male-specific androgenic gland (AG), called insulin-like androgenic gland factor (IAG), plays an essential role in sexual maturity. Specifically IAG is involved in developing male primary and secondary sexual characteristics including spermatogenesis. This study aimed first to identify the IAG, then examine if season influences IAG expression in C. borealis males. Finally, the AG transcriptome was used to test if eyestalk neuropeptides regulate IAG levels via an endocrine axis between the two endocrine tissues as established in other crustaceans. The full-length CabIAG sequence is 928 nucleotides long, encoding a 151 amino acid deduced sequence. The CabIAG identified from the AG transcriptome after eyestalk ablation was the most highly expressed gene and accounted for up to 25% of transcripts, further confirming the presence of an endocrine axis between the androgenic gland and eyestalk ganglia. This gene expression was exclusive in male C. borealis AG. The transcriptomic analysis also revealed strong upregulation of the PPOAE transcript and downregulation of proteolytic enzymes. The CabIAG levels differ by season, increasing AG activity in fall and possibly coinciding with high mating activity. The timing of increased AG activity correlating to mating with females should be considered for better stock management for the C. borealis population.
Pretravel plans and discrepant trip experiences among travelers attending a tertiary care centre family travel medicine clinic
Authors: Wong Jacqueline K. , Nashid Nancy , Pell Lisa G. , Lam Ray E. , Louch Debra M. , Science Michelle E. , Morris Shaun K.
Published: February 2022

Background

International travel can expose travelers to a number of health risks. Pretravel consultation (PC) helps mitigate risk and prepare travelers for health concerns that might arise. The assessment of risk, mitigation strategies, and relevance of pretravel advice is dependent on how closely travelers adhere to their planned travel itinerary and activities. We determined the proportion of returned travelers whose completed travel experiences differed from their stated travel itineraries, and identified discrepancies that significantly altered the traveler’s health risk and would have required alternative counseling during their PC.

Methods

We conducted a prospective cohort study at the SickKids’ Family Travel Clinic between October 2014 and November 2015. Returned travelers who completed a post-travel survey were included. Pretravel consultation assessments and post-trip surveys were compared to identify discrepant trip experiences.

Results

A total of 389 travelers presented to the clinic for a PC during the study period and 302 (77.6%) were enrolled. Post-travel surveys were received from 119 (39.4%) participants, representing 101 unique itineraries. The median participant age was 36.3 years (IQR 26.6–47.5) and there were 73 female travelers (61%). Most participants (n = 87,73%) were healthy as well as Canadian born (n = 84, 71%). A quarter of travelers were visiting friends and relatives (VFR) (n = 30, 25.2%). The vast majority of returned travelers (n = 109, 92%) reported discrepant trip experiences involving trip duration, countries visited, accommodations, environmental surroundings and/or activities. Almost two thirds of these individuals (n = 68, 62%) would have required alternative pretravel counseling. We did not identify any demographic or planned trip characteristics that predicted discrepant trip experiences requiring alternative pretravel counseling.

Conclusions

The majority of travelers reported discrepant trip experiences and the discrepancies often affected health risk. Therefore, clinicians should consider providing broader counselling during the PC as discrepancies from planned travel are common.
The spike-and-slab elastic net as a classification tool in Alzheimer’s disease
Authors: Leach Justin M. , Edwards Lloyd J. , Kana Rajesh , Visscher Kristina , Yi Nengjun , Aban Inmaculada ,   for the Alzheimer’s Disease Neuroimaging Initiative
Published: February 2022

Alzheimer’s disease (AD) is the leading cause of dementia and has received considerable research attention, including using neuroimaging biomarkers to classify patients and/or predict disease progression. Generalized linear models, e.g., logistic regression, can be used as classifiers, but since the spatial measurements are correlated and often outnumber subjects, penalized and/or Bayesian models will be identifiable, while classical models often will not. Many useful models, e.g., the elastic net and spike-and-slab lasso, perform automatic variable selection, which removes extraneous predictors and reduces model variance, but neither model exploits spatial information in selecting variables. Spatial information can be incorporated into variable selection by placing intrinsic autoregressive priors on the logit probabilities of inclusion within a spike-and-slab elastic net framework. We demonstrate the ability of this framework to improve classification performance by using cortical thickness and tau-PET images from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to classify subjects as cognitively normal or having dementia, and by using a simulation study to examine model performance using finer resolution images.
Inter- and intradialytic fluid volume changes and vascular stiffness parameters in patients on hemodialysis
Authors: Lafta Aya , Ukrainetz Judy , Davison Sara , Thompson Stephanie , Bello Aminu , Braam Branko
Published: February 2022

Background

Whether fluid overload is associated with vascular stiffness parameters in hemodialysis (HD) patients has not been fully elucidated. We hypothesized that interdialytic fluid accumulation increases vascular stiffness parameters, which improves with intradialytic ultrafiltration.

Methods

Fluid overload and vascular stiffness parameters were assessed in 39 HD patients (20 with and 19 without fluid overload) and compared to 26 healthy controls. Fluid status was assessed 15 minutes before the mid-week HD session by bio-impedance spectroscopy. Following this, ambulatory pulse wave velocity (PWV) and augmentation index (AIx) were measured for 24 hours before another mid-week HD session and then for 5 hours starting 30 minutes before and ending 30 minutes after the session.

Results

HD patients had significant fluid overload compared to healthy controls (2.0±2.4 vs. -0.2±0.6 L; P<0.001) and baseline PWV was higher (10.3±1.7 vs. 8.8±1.4 m/s; P<0.001). There was no significant difference between PWV and AIx in fluid overloaded and non-fluid overloaded HD patients prior to, or during the HD session. AIx of non-fluid overloaded HD patients improved after the HD session (P = 0.04). Average 24-hour AIx was higher in fluid overloaded HD patients (P<0.001).

Conclusions

Inter- and intradialytic changes in fluid volume were only weakly related to vascular stiffness parameters in HD patients. Although there was a modest reduction in AIx in non-fluid overloaded HD patients after the dialysis session, fluid removal did not improve vascular stiffness parameters during the HD session. We speculate that the effect of fluid overload correction on vascular stiffness parameters requires long-term adjustments in the vasculature.
Costs, benefits, and cost-benefit of Collaborative Assessment and Management of Suicidality versus enhanced treatment as usual
Authors: McCutchan Phoebe K. , Yates Brian T. , Jobes David A. , Kerbrat Amanda H. , Comtois Katherine Anne
Published: February 2022

Suicide rates have been steadily increasing in both the U.S. general population and military, with significant psychological and economic consequences. The purpose of the current study was to examine the economic costs and cost-benefit of the suicide-focused Collaborative Assessment and Management of Suicidality (CAMS) intervention versus enhanced treatment as usual (ETAU) in an active duty military sample using data from a recent randomized controlled trial of CAMS versus ETAU. The full intent-to-treat sample included 148 participants (mean age 26.8 years ± 5.9 SD years, 80% male, 53% White). Using a micro-costing approach, the cost of each condition was calculated at the individual level from a healthcare system perspective. Benefits were estimated at the individual level as cost savings in past-year healthcare expenditures based on direct care reimbursement rates. Cost-benefit was examined in the form of cost-benefit ratios and net benefit. Total costs, benefits, cost-benefit ratios, and net benefit were calculated and analyzed using general linear mixed modeling on multiply imputed datasets. Results indicated that treatment costs did not differ significantly between conditions; however, CAMS was found to produce significantly greater benefit in the form of decreased healthcare expenditures at 6-month follow-up. CAMS also demonstrated significantly greater cost-benefit ratios (i.e., benefit per dollar spent on treatment) and net-benefit (i.e., total benefit less the cost of treatment) at 12-month follow-up. The current study suggests that beyond its clinical effectiveness, CAMS may also convey potential economic advantages over usual care for the treatment of suicidal active duty service members. Our findings demonstrate cost savings in the form of reduced healthcare expenditures, which theoretically represent resources that can be reallocated toward other healthcare system needs, and thus lend support toward the overall value of CAMS.
Feasibility of dual-energy CBCT by spectral filtration of a dual-focus CNT x-ray source
Authors: Li Boyuan , Spronk Derrek , Luo Yueting , Puett Connor , Inscoe Christina R. , Tyndall Donald A. , Lee Yueh Z. , Lu Jianping , Zhou Otto
Published: February 2022

Cone beam computed tomography (CBCT) is now widely used in dentistry and growing areas of medical imaging. The presence of strong metal artifacts is however a major concern of using CBCT especially in dentistry due to the presence of highly attenuating dental restorations, fixed appliances, and implants. Virtual monoenergetic images (VMIs) synthesized from dual energy CT (DECT) datasets are known to reduce metal artifacts. Although several techniques exist for DECT imaging, they in general come with significantly increased equipment cost and not available in dental clinics. The objectives of this study were to investigate the feasibility of developing a low-cost dual energy CBCT (DE-CBCT) by retrofitting a regular CBCT scanner with a carbon nanotube (CNT) x-ray source with dual focal spots and corresponding low-energy (LE) and high-energy (HE) spectral filters. A testbed with a CNT field emission x-ray source (NuRay Technology, Chang Zhou, China), a flat panel detector (Teledyne, Waterloo, Canada), and a rotating object stage was used for this feasibility study. Two distinct polychromatic x-ray spectra with the mean photon energies of 66.7keV and 86.3keV were produced at a fixed 120kVp x-ray tube voltage by using Al+Au and Al+Sn foils as the respective LE and HE filters attached to the exist window of the x-ray source. The HE filter attenuated the x-ray photons more than the LE filter. The calculated post-object air kerma rate of the HE beam was 31.7% of the LE beam. An anthropomorphic head phantom (RANDO, Nuclear Associates, Hicksville, NY) with metal beads was imaged using the testbed and the images were reconstructed using an iterative volumetric CT reconstruction algorithm. The VMIs were synthesized using an image-domain basis materials decomposition method with energy ranging from 30 to 150keV. The results were compared to the reconstructed images from a single energy clinical dental CBCT scanner (CS9300, Carestream Dental, Atlanta, GA). A significant reduction of the metal artifacts was observed in the VMI images synthesized at high energies compared to those from the same object imaged by the clinical dental CBCT scanner. The ability of the CNT x-ray source to generate the output needed to compensate the reduction of photon flux due to attenuation from the spectral filters and to maintain the CT imaging time was evaluated. The results demonstrated the feasibility of DE-CBCT imaging using the proposed approach. Metal artifact reduction was achieved in VMIs synthesized. The x-ray output needed for the proposed DE-CBCT can be generated by a fixed-anode CNT x-ray source.
Antimicrobial stewardship: Attitudes and practices of healthcare providers in selected health facilities in Uganda
Authors: Kimbowa Isaac Magulu , Eriksen Jaran , Nakafeero Mary , Obua Celestino , Lundborg Cecilia Stålsby , Kalyango Joan , Ocan Moses
Published: February 2022

Though antimicrobial stewardship (AMS) programmes are the cornerstone of Uganda’s national action plan (NAP) on antimicrobial resistance, there is limited evidence on AMS attitude and practices among healthcare providers in health facilities in Uganda. We determined healthcare providers’ AMS attitudes, practices, and associated factors in selected health facilities in Uganda. We conducted a cross-sectional study among nurses, clinical officers, pharmacy technicians, medical officers, pharmacists, and medical specialists in 32 selected health facilities in Uganda. Data were collected once from each healthcare provider in the period from October 2019 to February 2020. Data were collected using an interview-administered questionnaire. AMS attitude and practice were analysed using descriptive statistics, where scores of AMS attitude and practices for healthcare providers were classified into high, fair, and low using a modified Blooms categorisation. Associations of AMS attitude and practice scores were determined using ordinal logistic regression. This study reported estimates of AMS attitude and practices, and odds ratios with 95% confidence intervals were reported. We adjusted for clustering at the health facility level using clustered robust standard errors. A total of 582 healthcare providers in 32 healthcare facilities were recruited into the study. More than half of the respondents (58%,340/582) had a high AMS attitude. Being a female (aOR: 0.66, 95% CI: 0.47–0.92, P < 0.016), having a bachelor’s degree (aOR: 1.81, 95% CI: 1.24–2.63, P < 0.002) or master’s (aOR: 2.06, 95% CI: 1.13–3.75, P < 0.018) were significant predictors of high AMS attitude. Most (46%, 261/582) healthcare providers had fair AMS practices. Healthcare providers in the western region’s health facilities were less likely to have a high AMS practice (aOR: 0.52, 95% CI 0.34–0.79, P < 0.002). In this study, most healthcare providers in health facilities had a high AMS attitude and fair AMS practice.
3D engineered human gingiva fabricated with electrospun collagen scaffolds provides a platform for in vitro analysis of gingival seal to abutment materials
Authors: Sakulpaptong Wichurat , Clairmonte Isabelle A. , Blackstone Britani N. , Leblebicioglu Binnaz , Powell Heather M.
Published: February 2022

In order to advance models of human oral mucosa towards routine use, these models must faithfully mimic the native tissue structure while also being scalable and cost efficient. The goal of this study was to develop a low-cost, keratinized human gingival model with high fidelity to human attached gingiva and demonstrate its utility for studying the implant-tissue interface. Primary human gingival fibroblasts (HGF) and keratinocytes (HGK) were isolated from clinically healthy gingival biopsies. Four matrices, electrospun collagen (ES), decellularized dermis (DD), type I collagen gels (Gel) and released type I collagen gels (Gel-R)) were tested to engineer lamina propria and gingiva. HGF viability was similar in all matrices except for Gel-R, which was significantly decreased. Cell penetration was largely limited to the top layers of all matrices. Histomorphometrically, engineered human gingiva was found to have similar appearance to the native normal human gingiva except absence of rete pegs. Immunohistochemical staining for cell phenotype, differentiation and extracellular matrix composition and organization within 3D engineered gingiva made with electrospun collagen was mostly in agreement with normal gingival tissue staining. Additionally, five types of dental material posts (5-mm diameter x 3-mm height) with different surface characteristics were used [machined titanium, SLA (sandblasted-acid etched) titanium, TiN-coated (titanium nitride-coated) titanium, ceramic, and PEEK (Polyetheretherketone) to investigate peri-implant soft tissue attachment studied by histology and SEM. Engineered epithelial and stromal tissue migration to the implant-gingival tissue interface was observed in machined, SLA, ceramic, and PEEK groups, while TiN was lacking attachment. Taken together, the results suggest that electrospun collagen scaffolds provide a scalable, reproducible and cost-effective lamina propria and 3D engineered gingiva that can be used to explore biomaterial-soft tissue interface.
Transcultural adaptation and validation of the Serbian version of the colorectal-specific quality of life questionnaire FACT-C
Authors: Ilic-Zivojinovic Jelena , Krdzic Igor , Jovanovic Ana , Vukasinovic Danka , Ilic Branislav , Gavrilovic Aleksandar , Soldatovic Ivan
Published: February 2022

Objective

Transcultural adaptation and validation of the FACT-C questionnaire to Serbian language.

Methods

The study included 131 patients with colorectal cancer. Translation included standard forward and backward translation from original language to Serbian and back. Pilot testing of the questionnaire was conducted on 10 patients with diagnosed colorectal cancer. The questionnaires EORTC-QLQ-C30 and DASS will be used as validated tools to evaluate validity of examined, FACT-C questionnaire.

Results

The FACT-C demonstrated satisfactory construct validity using Cronbach’s alpha. Satisfactory concurrent validity was demonstrated using correlations with EORTC-QLQ-C30 and DASS questionnaires. High reproducibility was demonstrated using repeated questionnaires on 30 patients two weeks after the first interview.

Conclusion

The Serbian version of the FACT-C was demonstrated to have satisfactory applicability, reliability and validity in Serbian patients with colorectal cancer. It can be considered as a valid colorectal cancer specific health related quality of life tool for the Serbian population.
Preparedness of tertiary care hospitals to implement the national TB infection prevention and control guidelines in Bangladesh: A qualitative exploration
Authors: Islam Md. Saiful , Tarannum Sayeeda , Banu Sayera , Chowdhury Kamal Ibne Amin , Nazneen Arifa , Chughtai Abrar Ahmad , Seale Holly
Published: February 2022

In high tuberculosis (TB) burden countries, health settings, including non-designated TB hospitals, host many patients with pulmonary TB. Bangladesh’s National TB Control Program aims to strengthen TB infection prevention and control (IPC) in health settings. However, there has been no published literature to date that assessed the preparedness of hospitals to comply with the recommendations. To address this gap, our study examined healthcare workers knowledge and attitudes towards TB IPC guidelines and their perceptions regarding the hospitals’ preparedness in Bangladesh. Between January to December 2019, we conducted 16 key-informant interviews and four focus group discussions with healthcare workers from two public tertiary care hospitals. In addition, we undertook a review of 13 documents [i.e., hospital policy, annual report, staff list, published manuscript]. Our findings showed that healthcare workers acknowledged the TB risk and were willing to implement the TB IPC measures but identified key barriers impacting implementation. Gaps were identified in: policy (no TB policy or guidelines in the hospital), health systems (healthcare workers were unaware of the guidelines, lack of TB IPC program, training and education, absence of healthcare-associated TB infection surveillance, low priority of TB IPC, no TB IPC monitoring and feedback, high patient load and bed occupancy, and limited supply of IPC resources) and behavioural factors (risk perception, compliance, and self and social stigma). The additional service-level gap was the lack of electronic medical record systems. These findings highlighted that while there is a demand amongst healthcare workers to implement TB IPC measures, the public tertiary care hospitals have got key issues to address. Therefore, the National TB Control Program may consider these gaps, provide TB IPC guidelines to these hospitals, assist them in developing hospital-level IPC manual, provide training, and coordinate with the ministry of health to allocate separate budget, staffing, and IPC resources to implement the control measures successfully.
Current and future distribution of Ixodes scapularis ticks in Québec: Field validation of a predictive model
Authors: Ripoche Marion , Bouchard Catherine , Irace-Cima Alejandra , Leighton Patrick , Thivierge Karine
Published: February 2022

The incidence of Lyme disease is increasing in Québec and is closely linked to the distribution ofIxodes scapularisticks. A time-to-establishment model developed in 2012 by Leighton and colleagues predicted the year of tick population establishment for each municipality in eastern Canada. To validate if this model correctly predicted tick distribution in Québec, predicted tick establishment was compared to field data from active tick surveillance (2010–2018) using two criteria: i) the detection of at least one tick and ii) the detection of the three questing stages of the tick. The speed of tick establishment and the increase in the exposed human population by 2100 were predicted with the time-to-establishment model. Field observations were consistent with model predictions. Ticks were detected on average 3 years after the predicted year. The probability of tick detection is significantly higher after the predicted year than before (61% vs 27% of collections). The trend was similar for the detection of three tick stages (16% vs 9% of collections). The average speed of tick range expansion was estimated by the model to be 18 km/year in Québec, with 90% of the human population exposed by 2027. The validation of the time-to-establishment model using field data confirmed that it could be used to projectI.scapularisrange expansion in Québec, and consequently the increase in Lyme disease risk over the coming decades. This will help public health authorities anticipate and adapt preventive measures, especially in areas not yet affected by Lyme disease.
How do multi-morbidity and polypharmacy affect general practice attendance and referral rates? A retrospective analysis of consultations
Authors: O’Regan Andrew , O’Doherty Jane , O’Connor Ray , Cullen Walter , Niranjan Vikram , Glynn Liam , Hannigan Ailish
Published: February 2022

Background

As prevalence of multimorbidity and polypharmacy rise, health care systems must respond to these challenges. Data is needed from general practice regarding the impact of age, number of chronic illnesses and medications on specific metrics of healthcare utilisation.

Methods

This was a retrospective study of general practices in a university-affiliated education and research network, consisting of 72 practices. Records from a random sample of 100 patients aged 50 years and over who attended each participating practice in the previous two years were analysed. Through manual record searching, data were collected on patient demographics, number of chronic illnesses and medications, numbers of attendances to the general practitioner (GP), practice nurse, home visits and referrals to a hospital doctor. Attendance and referral rates were expressed per person-years for each demographic variable and the ratio of attendance to referral rate was also calculated.

Results

Of the 72 practices invited to participate, 68 (94%) accepted, providing complete data on a total of 6603 patients’ records and 89,667 consultations with the GP or practice nurse; 50.1% of patients had been referred to hospital in the previous two years. The attendance rate to general practice was 4.94 per person per year and the referral rate to the hospital was 0.6 per person per year, giving a ratio of over eight attendances for every referral. Increasing age, number of chronic illnesses and number of medications were associated with increased attendance rates to the GP and practice nurse and home visits but did not significantly increase the ratio of attendance to referral rate.

Discussion

As age, morbidity and number of medications rise, so too do all types of consultations in general practice. However, the rate of referral remains relatively stable. General practice must be supported to provide person centred care to an ageing population with rising rates of multi-morbidity and polypharmacy.