bluuebunny/crossref_metadata_2025 huggingface dataset:
Hand hygiene compliance and its associated factors among health care providers in primary hospitals of Waghimira Zone, Northeast Ethiopia: a mixed study design
Authors: Alene Melese , Tamiru Dessalegn , Bazie Getaw Walle , Mebratu Wondwosen , Kebede Natnael
Published: May 2022

Introduction

Hand hygiene compliance is the problem of developing nations particularly in Sub-Saharan Africa including Ethiopia. Despite a lot of efforts have been employed, healthcare-associated infections are the existing health care problems, leading to impaired quality of life, prolonged hospital stays, increased healthcare costs, morbidity and mortality. This study aimed to assess the magnitude and factors associated with hand hygiene compliance among health care providers working at the primary hospitals of Waghimira Zone, Northeast Ethiopia.

Methods

Facility-based cross-sectional study design supplemented with qualitative research method was employed at the primary hospitals of Waghimira Zone from March 02–15, 2020. Simple random sampling using lottery method was applied to select 253 study participants. The data were coded on pre-arranged coding sheet and entered into Epi-Data version 3.1 and exported to SPSS version 25 for analysis. Descriptive statistics were displayed using tables and figures. Binary logistic regression analysis was used to test associations between the independent and the outcome variable. Multivariable logistic regression analysis was fitted to identify the independent predictors of hand-hygiene compliance at p-value < 0.05 and AOR with 95% confidence interval. Six Key Informant Interviews were conducted with purposively selected chief executive and clinical officers. Thematic content analysis was made and the findings were written sequentially with explanatory method.

Results

One-fifth of the subjects (20.6%, 95% CI = 15.2, 24.9) had good hand hygiene compliance. Attended training on hand hygiene protocol (AOR = 3.18, 95% CI: 1.39, 7.28), accessible to adequate soap and water (AOR = 3.77, 95%CI: 1.52, 9.37), having alcohol for hand rub (AOR = 2.67, 95%CI: 1.18, 6.05) and having hand wash sink (AOR = 2.31, 95%CI: 1.03, 5.14) were significantly associated with hand hygiene compliance which also supported by the qualitative findings.

Conclusions

Hand hygiene compliance among health care providers was low in the study area. Attended training on hand hygiene, accessibility to adequate soap and water, alcohol-based hand rub, and having hand washing sink in working area were statistically significant. Hence, the primary hospitals should be equipped with adequate supply to all the basic hand hygiene facilities.
Intratumor microbiome in cancer progression: current developments, challenges and future trends
Authors: Liu Jinyan , Zhang Yi
Published: May 2022

Cancer is a complicated disease attributed to multifactorial changes, which causes difficulties with treatment strategies. Various factors have been regarded as the main contributors, and infectious etiological factors have recently attracted interest. Several microbiomes contribute to carcinogenesis, cancer progression, and modulating cancer treatment by inducing cancerous epithelial cells and chronic inflammation. Most of our knowledge on the role of microbiota in tumor oncogenesis and clinical efficiency is associated with the intestinal microbiome. However, compelling evidence has also confirmed the contribution of the intratumor microbiome in cancer. Indeed, the findings of clinical tumor samples, animal models, and studies in vitro have revealed that many intratumor microbiomes promote tumorigenesis and immune evasion. In addition, the intratumor microbiome participates in regulating the immune response and even affects the outcomes of cancer treatment. This review summarizes the interplay between the intratumor microbiota and cancer, focusing on the contribution and mechanism of intratumor microbiota in cancer initiation, progression, and potential applications to cancer therapy.
A BERTweet-based design for monitoring behaviour change based on five doors theory on coral bleaching campaign
Authors: Harywanto Gabriela Nathania , Veron Juan Sebastian , Suhartono Derwin
Published: May 2022

Coral reefs are very important ecosystem which are the foundation of all life on this earth, but now they are under threat. Coral bleaching are happening now at a serious rate and the ultimate goal of conservation effort toward this issue is behaviour change. One of the most important parts of conservation effort is monitoring. However, monitoring the success of the coral bleaching campaign on behaviour change requires extensive data collection so traditional methods are not effective because they require resources that may not be met. The goal of this study is to build fast and vast automation in analyzing the stage of behaviour change. Social media data has prospect to become good alternative to be used because social media usage is currently increasing every year, including Twitter. Therefore, an automatic classification model was designed which can identify the stages of behaviour change based on the Five Doors Theory on Twitter. Five Doors Theory define 5 stages of behavior change: Desirability, Enabling Context, Can Do, Buzz, and Invitation. The data was fetched through a trusted repository, Mendeley Data, with title "An Annotated Dataset for Identifying Behaviour Change Based on Five Doors Theory Under Coral Bleaching Phenomenon on Twitter". There are 1,222 tweets with keywords related to coral bleaching that have been annotated according to the behaviour change stages. There are two proposed designs: embedding extraction which utilizes the output of each encoder layer in BERTweet and stacking ensemble which uses several BERTweet models with different hyperparameters that are ensembled using a logistic regression model. The best accuracy of 0.7796 with an f1-score of 0.7945 was obtained in the stacking ensemble design scenario. The classification model created can identify each class at the stage of behaviour change well, even though the dataset is unbalanced in its distribution. The proposed design has a performance that exceeds all baseline models and the standalone BERTweet. In conclusion, the automatic classification model create the process of monitoring the stages of behavior change run effectively and efficiently so that the success of the coral bleaching campaign can be monitored and achieved.
Prognostic significance of COVID-19 MSCT chest findings on short-term disease progression
Authors: Faheem Mohamed H. , Gomaa Amr , Allam Amira H.
Published: May 2022

Background

CT has been used on a massive scale to help identify and investigate suspected or confirmed cases of COVID-19 pneumonia. This study aimed to assess the prognostic significance of the chest findings MSCT of COVID-19 patients and to determine if prognosis can rely on the initial CT imaging.

Methods

The study design was retrospective cohort study. It was carried out on 300 patients presented to the chest outpatient clinics in Benha University hospitals and El Abbassia Chest Hospital with clinical picture suggestive of COVID-19 infection. The CT finding were then compared to the short-term clinical outcome of the patients (1–3 weeks), acquired from the hospital patient data archive. According to the progression of the respiratory symptoms (including dyspnea, respiratory rate, and O2 saturation), the short-term clinical outcome of the patients was classified into 4 groups: group A (mild cases), group B (moderate cases), group C (severe cases), and group D (fatality cases).

Results

Consolidations, septal thickening, crazy paving, and fibrotic bands were significantly higher in groups C and D than group A and B (P-value < 0.001 for all variants). Nodules show statistically significant higher incidence in groups A and B than group C and D (P-value < 0.001). The CT severity score shows statistically significant increase with the poor short-term clinical outcomes (groups C and D) (P-value < 0.001).

Conclusion

CT chest is a good radiological marker that can help in predicting short-term clinical outcome in COVID-19 patient. Higher CT severity scores are predictors of poorer clinical prognosis.
Evidence of learning walks related to scorpion home burrow navigation
Authors: Gaffin Douglas D. , Muñoz Maria G. , Hoefnagels Mariëlle H.
Published: May 2022

The navigation by chemo-textural familiarity hypothesis (NCFH) suggests that scorpions use their midventral pectines to gather chemical and textural information near their burrows and use this information as they subsequently return home. For NCFH to be viable, animals must somehow acquire home-directed ‘tastes’ of the substrate, such as through path integration (PI) and/or learning walks. We conducted laboratory behavioral trials using desert grassland scorpions (Paruroctonus utahensis). Animals reliably formed burrows in small mounds of sand we provided in the middle of circular, sand-lined behavioral arenas. We processed overnight infrared video recordings with a MATLAB script that tracked animal movements at 1–2 s intervals. In all, we analyzed the movements of 23 animals, representing nearly 1500 h of video recording. We found that once animals established their home burrows, they immediately made one to several short, looping excursions away from and back to their burrows before walking greater distances. We also observed similar excursions when animals made burrows in level sand in the middle of the arena (i.e. no mound provided). These putative learning walks, together with recently reported PI in scorpions, may provide the crucial home-directed information requisite for NCFH.
Trimetallic Mixture of Ni(III), Pd(III) and Au(III) Ions in a Molecule-Based Bromide-Bridged MX-Chain Compound
Authors: Wakizaka Masanori , Wu Hashen , Li Zhao-Yang , Iguchi Hiroaki , Takaishi Shinya , Yamashita Masahiro
Published: May 2022

Multi-metallic inorganic alloy materials have attracted great attention recently. Additionally, molecule-based materials have wide designability in terms of their structures and electronic states. These are two different ideas. Here, we report the mixing of Pd(III) and Au(III) ions into a bromide-bridged molecular chain compound [Ni(chxn)2Br]Br2 (chxn: 1R,2R-diaminocyclohexane) to form an average formula of [Ni0.853Pd0.142Au0.005(chxn)2Br]Br2, which was synthesized by an electrochemical oxidation method. This trimetallic material is revealed to be a Mott–Hubbard state semiconductor with a one-dimensional electronic system like that of [Ni(chxn)2Br]Br2, whereas it shows a smaller activation energy for conductivity than that of pristine [Ni(chxn)2Br]Br2. This work represents a fusion of the concepts of multi-metallic and molecule-based materials using a 1D compound.
Screening Inattentive Buyers
Authors: Mensch Jeffrey
Published: May 2022

Information plays a crucial role in mechanism design problems. A potential complication is that buyers may be inattentive, and so their information may endogenously and flexibly depend on the offered mechanism. I show that it is without loss of generality to consider contour mechanisms, which comprise triplets of allocation probabilities, prices, and beliefs, and are uniquely determined by a single such point. The mechanism design problem then reduces to Bayesian persuasion along the optimal contour. This reduction has significant implications for both the implementation of the optimal mechanism and the revenues that can be achieved. (JEL C11, D11, D82, D83)
Spreading Gangs: Exporting US Criminal Capital to El Salvador
Authors: Sviatschi Maria Micaela
Published: May 2022

This paper shows how deportation policies can backfire by disseminating not only ideas between countries but also criminal networks, spreading gangs, in this case, across El Salvador, and spurring migration back to the United States. In 1996, the US Illegal Immigration Responsibility Act increased the number of criminal deportations. In particular, the members of large Salvadoran gangs developed in Los Angeles were sent back to El Salvador. Using variation in criminal deportations over time and across cohorts, combined with geographical variation in US gangs’ location, I find that these deportations led to an increase in homicide rates and gang activity, as well as an increase in gang recruitment and migration of children. (JEL J15, J18, K37, K42, O17)
Efficient Matching in the School Choice Problem
Authors: Reny Philip J.
Published: May 2022

Stable matchings in school choice needn’t be Pareto efficient and can leave thousands of students worse off than necessary. Call a matching μ priority-neutral if no matching can make any student whose priority is violated by μ better off without violating the priority of some student who is made worse off. Call a matching priority-efficient if it is priority-neutral and Pareto efficient. We show that there is a unique priority-efficient matching and that it dominates every priority-neutral matching and every stable matching. Moreover, truth-telling is a maxmin optimal strategy for every student in the mechanism that selects the priority-efficient matching. (JEL C78, I21, I28)
P2P Lending platforms in Malaysia: the awareness among Malaysian adults
Authors: Nguyen Lan Thi Phuong , Muthaiyah Saravanan , Sy Malick Ousmane , Kalabeke Wisdom
Published: May 2022

Background - Since 2016, the Securities Commission (SC) in Malaysia has given licenses to only eleven P2P lending platforms. Such lending platforms are expected to disrupt the lending services of traditional lenders in the coming years. However, being still in their infant stages, it is essential to know the extent to which such platforms are made known to potential investors out there.

This study aims to examine the awareness level of the eleven P2P lending platforms among Malaysian adults. The study also explores if past investment experience and financial knowledge would influence such awareness from Malaysian adults.

 Methods - A sample of 335 Malaysian individuals was used for this study. An online questionnaire was designed with three main parts: demographic, financial literacy, and P2P lending awareness. Using IBM SPSS Statistics 26, frequency, descriptive, normality, Pearson coefficients and multiple regression analyses were carried out. 

Results - Although seven out of ten respondents have good knowledge in three areas of finance: compounding rate, inflation and diversification, only 14.33% had a good and excellent awareness level of P2P lending. Thus, one would expect lesser awareness about P2P lending among Malaysian adults whose financial literacy is poor or zero. Test results from multiple regression analysis suggest that past lending experiences positively affect the awareness of P2P lending in Malaysia, but not the financial literacy.

Conclusions - the awareness about P2P lending among Malaysian adults is too low, despite their high level of education and financial literacy. No investing experience and not knowing any existing P2P lending in the country may be the reason for this low awareness. Therefore, for P2P lending to thrive in Malaysia, the eleven P2P lending platforms need to be promoted aggressively in various social media outlets.
The lifetime revision risk of unicompartmental knee arthroplasty
Authors: Tay Mei L. , Young Simon W. , Frampton Christopher M. , Hooper Gary J.
Published: May 2022

Aims

Unicompartmental knee arthroplasty (UKA) has a higher risk of revision than total knee arthroplasty (TKA), particularly for younger patients. The outcome of knee arthroplasty is typically defined as implant survival or revision incidence after a defined number of years. This can be difficult for patients to conceptualize. We aimed to calculate the ‘lifetime risk’ of revision for UKA as a more meaningful estimate of risk projection over a patient’s remaining lifetime, and to compare this to TKA.

Methods

Incidence of revision and mortality for all primary UKAs performed from 1999 to 2019 (n = 13,481) was obtained from the New Zealand Joint Registry (NZJR). Lifetime risk of revision was calculated for patients and stratified by age, sex, and American Society of Anesthesiologists (ASA) grade.

Results

The lifetime risk of revision was highest in the youngest age group (46 to 50 years; 40.4%) and decreased sequentially to the oldest (86 to 90 years; 3.7%). Across all age groups, lifetime risk of revision was higher for females (ranging from 4.3% to 43.4% vs males 2.9% to 37.4%) and patients with a higher ASA grade (ASA 3 to 4, ranging from 8.8% to 41.2% vs ASA 1 1.8% to 29.8%). The lifetime risk of revision for UKA was double that of TKA across all age groups (ranging from 3.7% to 40.4% for UKA, and 1.6% to 22.4% for TKA). The higher risk of revision in younger patients was associated with aseptic loosening in both sexes and pain in females. Periprosthetic joint infection (PJI) accounted for 4% of all UKA revisions, in contrast with 27% for TKA; the risk of PJI was higher for males than females for both procedures.

Conclusion

Lifetime risk of revision may be a more meaningful measure of arthroplasty outcomes than implant survival at defined time periods. This study highlights the higher lifetime risk of UKA revision for younger patients, females, and those with a higher ASA grade, which can aid with patient counselling prior to UKA. Cite this article: Bone Joint J 2022;104-B(6):672–679.
Analisis Sentimen dari Aplikasi Shopee Indonesia Menggunakan Metode Recurrent Neural Network
Authors: Utami Herni
Published: May 2022

Sentiment analysis on unbalanced data will cause classification errors where the classification results tend to be in the majority class. Therefore, it is necessary to handle unbalanced data. In this study, a combination of synthetic minority oversampling technique (SMOTE) and Tomek link methods will be used to handle unbalanced data. In this study, we use the Recurrent Neural Network (RNN) method to analyze the sentiment of Shopee application users based on review data. Shopee Indonesia application review data shows that around 80% of Shopee application users have positive sentiments and 20% have negative sentiments, which means the data is not balance. In this study, preprocessing process with combination of synthetic minority oversampling technique (SMOTE) and Tomek link method used to handle the condition. The performance of the result is quite good, namely 80% accuracy, 84.1% precision, 92.5% sensitivity, 30% specificity, and 88.1% F1-score. It is better than performance of sentiment analysis that without preprocessing to handle imbalanced data.

Keywords: sentiment analysis; imbalanced data; Tomek link; SMOTE; RNN
Patient, Procedure, People (PPP): recognising and responding to intraoperative critical events
Authors: Hardie JA , Hunn D , Mitchell TE , Brennan PA
Published: May 2022

Intraoperative critical events are rarely experienced by individual surgeons but are commonly experienced at a workforce level. Finding unfamiliar or unexpected pathology, anatomy, haemorrhage or an iatrogenic organ or structure injury cannot be completely eliminated in the complex surgical environment. It is vital that an appropriate, safe response to these infrequent events takes place to prevent possible further harm to patients. This paper introduces ‘Patient, Procedure, People’, a tool adapted from aviation threat and error management (TEM) training. It allows surgical teams to improve situational awareness (SA), communicate effectively, flatten team hierarchy gradients and improve decision-making before responding to critical events. We review factors contributing to poor decision-making, with resulting errors. These include loss of SA (tunnel vision), acute stress reactions (fight–flight or freeze–hide) and limbic hijacking (surprise and startle events). Events may cause workload to increase beyond cognitive capacity, further exacerbating the situation. After completing initial actions to achieve a temporary ‘place of safety’, surgical teams may use the tool to effectively manage threat or mitigate error. Aviation is a high-reliability organisation that has pioneered human factors research and training. Airline pilots undergo regular simulated emergencies assessment, including mandatory human factors assessment. Although the complexities of the operating theatre do not currently lend themselves to high-fidelity simulation as in aviation, valuable transferrable lessons can be learnt from aviation’s approach to TEM.
Management of idiopathic granulomatous mastitis: a prospective study
Authors: Sarkar DK , Banerjee R , Gupta S , Singhal AK , Halder A
Published: May 2022

Introduction

Idiopathic granulomatous mastitis (IGM) is an evolving problem with varied presentation. No definite treatment guidelines are available at present that may reduce rate of recurrence. Current evidence suggests a ductal pathology behind IGM, which leads to periductal mastitis, leakage and sinus/fistula formation. Thus, excision of the sinus/fistulous tract with en-bloc wide local excision (WLE) of the lesion could be curative. The objective of this study was to look for the basic aetiology of IGM and evaluate the effectiveness of WLE with total or partial duct excision as a curative approach.

Methods

An institutional prospective comparative study was conducted over 4 years (2015–2019), in which 59 cases of IGM were randomly divided into three groups. After necessary investigations, patients in group A received steroid therapy, those in group B received WLE and patients in group C received WLE with total or partial duct excision as the mode of treatment. Postoperative follow-up was between 6 months and 3 years.

Results

Histopathological examination (HPE) was found to be the most suitable diagnostic procedure. Patients in group B showed the highest rate of recurrence (73.6%), followed by group A (35.0%) and group C (5.0%). Patients in group C had a significantly lower chance of recurrence compared with both group A and group B (p < 0.05). HPE reports of excised ducts from patients in group C showed ductal disruption and leakage along with periductal granuloma in 70% of cases.

Conclusions

The presence of duct granuloma indicates the association of ductal pathology in IGM. IGM is therefore a disease of the mammary ducts and en-bloc duct excision is curative in non-responding cases.
Emphysematous cystitis: an incidental finding with varying outcomes
Authors: Tan TJ , Parmar K , Mukherjee A , Sonawane P , Badrakumar C
Published: May 2022

Emphysematous cystitis (EC) is a rare severe urinary tract infection characterised by pockets of air in and around the urinary bladder wall caused by gas-forming organisms. Common predisposing factors are chronic infection, immunosuppression, diabetes and neurogenic bladder. The presentation may vary from mild illness to severe life-threatening cystitis. We report two cases of incidental detection of EC diagnosed on imaging for the evaluation of unrelated symptoms. Although asymptomatic, this lethal disease still warrants prompt recognition and treatment with broad-spectrum antibiotics and urinary bladder drainage to prevent severe morbidity and mortality.
End-to-end optimization of optical systems with extended depth of field under wide spectrum illumination
Authors: Fontbonne Alice , Sauer Hervé , Goudail François
Published: May 2022

We study a way to take into account the scene illumination spectrum during end-to-end optimization of optical-digital hybrid systems that include annular binary phase masks to enhance their depth of field (DoF). We show that a phase mask specifically optimized for wide spectrum panchromatic imaging performs better under this type of illumination than phase masks optimized under monochromatic illumination assumption. Indeed, thanks to spectral averaging, the modulation transfer functions of such a phase mask are very close to each other. This guarantees a very homogeneous image quality across the DoF range, which we demonstrate theoretically and experimentally using a dedicated optical setup.
Conception of a single-component broadband high-resolution plane-VLS-grating monochromator
Authors: Kolesnikov Aleksei , Vishnyakov Evgeny , Shatokhin Alexey , Ragozin Evgeny
Published: May 2022

We propose a broadband single-element monochromator with a constant deviation angle and fixed slits for the wavelength range of 3–60 nm, which uses a grazing incidence plane varied line-space (VLS) grating with exponential dependence of line frequency across the aperture. Wavelength scanning is performed by translating the VLS grating along its surface. The deviation angle is constant, and the source, input, and output slits are stationary. With an exit slit (or CCD pixel size) of 6 µm, the practical resolving power

λ

/

δ
λ
=
6000

remains constant throughout the operating range. The proposed scheme is compared with a narrowband specialized monochromator (

135
±
4

Å) with the same acceptance angle, in which wavelength scanning is performed by rotating a plane VLS grating, as well as with a Rowland monochromator with a similar acceptance.
Enhanced supercontinuum generation and dispersive wave emission in a silicon nitride waveguide pumped at 1550  nm telecom wavelength
Authors: Lin Kaibin , Li Qian
Published: May 2022

We have numerically demonstrated that supercontinuum (SC) generation and dispersive wave (DW) emission in a silicon nitride waveguide can be actively controlled harnessing the weak continuous wave (CW) trigger scenario. The detailed simulation results suggest that the SC bandwidth, the temporal coherence, and the conversion of DWs are significantly enhanced after applying the CW trigger at the selected frequencies. These results are analyzed through the pump depletion occurring in the nonlinear propagation process. By tuning the CW trigger power, the CW power requirement for this approach is proved to be as low as

1

0

−
5

of the pump peak power. These numerical investigations provide valuable insight into obtaining the on-chip enhanced SC and DWs with an active control method.
Low cross talk crescent-shaped pore-assisted few-mode multi-core optical fiber for optical communication
Authors: Wang Guorui , Zhang Jiwei , Zhang Han , Wang Fang , Yan Xin , Zhang Xuenan , Li Shuguang , Cheng Tonglei
Published: May 2022

In this paper, we propose a crescent-shaped pore-assisted structure to realize a few-mode multi-core (four-mode six-core) optical fiber with low inter-core cross talk for large-capacity long-distance communication. Using the finite element method, a theoretical analysis is conducted at a working wavelength of 1550 nm, where the proposed optical fiber achieves a total loss of less than 0.2 dB/km and an effective mode field area of greater than

108

µ

m

2

. The inter-core cross talk of the fiber is less than

−

56

d
B

/

100

k
m

, and the relative multiplexing factor reaches up to 28.3, which significantly increases the core density. The maximum dispersion of the four supported linear polarization modes is less than

5.85

p
s

/

(

n
m
×
k
m

)

, which is greatly advantageous in communication systems. In addition, the fabrication scheme of the proposed optical fiber is practical, and its standard-compatible 42 µm core pitch promises the feasibility of integration with commercial optical networks.
Dexterous holographic trapping of dark-seeking particles with Zernike holograms
Authors: Abacousnac Jatin , Grier David G.
Published: May 2022

The intensity distribution of a holographically-projected optical trap can be tailored to the physical properties of the particles it is intended to trap. Dynamic optimization is especially desirable for manipulating dark-seeking particles that are repelled by conventional optical tweezers, and even more so when dark-seeking particles coexist in the same system as light-seeking particles. We address the need for dexterous manipulation of dark-seeking particles by introducing a class of “dark” traps created from the superposition of two out-of-phase Gaussian modes with different waist diameters. Interference in the difference-of-Gaussians (DoG) trap creates a dark central core that is completely surrounded by light and therefore can trap dark-seeking particles rigidly in three dimensions. DoG traps can be combined with conventional optical tweezers and other types of traps for use in heterogeneous samples. The ideal hologram for a DoG trap being purely real-valued, we introduce a general method based on the Zernike phase-contrast principle to project real-valued holograms with the phase-only diffractive optical elements used in standard holographic optical trapping systems. We demonstrate the capabilities of DoG traps (and Zernike holograms) through experimental studies on high-index, low-index and absorbing colloidal particles dispersed in fluid media.
Efficient high-power sub-50-fs gigahertz repetition rate diode-pumped solid-state laser
Authors: Hamrouni Marin , Labaye François , Modsching Norbert , Wittwer Valentin J. , Südmeyer Thomas
Published: May 2022

In this article we present a directly diode-pumped high-power Kerr-lens mode-locked Yb:CALGO bulk laser oscillator operating at 1-GHz repetition rate. We report on two laser configurations optimized for either highest average power or shortest pulse duration. In the first configuration optimized for high average power, the oscillator delivers up to 6.9 W of average power, which is the highest average power of any ultrafast laser oscillator operating at gigahertz repetition rate. The 93-fs pulses have a peak power of 64 kW, and the optical-to-optical efficiency amounts to 37%. In the second configuration optimized for short pulse duration, we demonstrate 48-fs pulses at 4.1 W of average power corresponding to a higher peak power of 74 kW with 21% optical-to-optical efficiency. This is the shortest pulse duration and the highest peak power demonstrated by any GHz-class Yb-based laser oscillator. The compact laser setup is directly pumped by a low-cost multimode fiber-coupled laser diode and has a high potential as an economical yet powerful source for various applications.
Temperature measurement of cloud or haze layers based on Raman rotational and vibrational spectra
Authors: Li Qimeng , Di Huige , Hua Dengxin , Yan Qing , Yuan Yun , Yang Tao
Published: May 2022

Pure rotational Raman lidar is often used for atmospheric temperature profile measurements. However, high elastic scattering suppression ratios (>107) are required for temperature measurement in clouds and haze, which imposes stringent requirements on spectral separation techniques. To solve this problem, a lidar measurement technique based on vibrational and rotational Raman spectra is proposed. Using nitrogen vibrational and rotational Raman scattering to obtain temperature profiles under strong elastic scattering, combined with the dual-rotational Raman temperature measurements under weak elastic scattering, a vertical distribution of atmospheric temperature including cloud and haze layers, can be obtained. The feasibility of the method was verified by numerical simulation. The Raman lidar for temperature measurements was established in Xi'an University of Technology, and the obtained temperature results show good agreement with the radiosonde measurements. The proposed method combines the high sensitivity of the dual-rotational Raman method and the high Mie-scattering suppression of the vibrational Raman method, thus further improving the adaptability of Raman lidar to cloudy and hazy air conditions and supporting atmospheric and cloud physics research.
Intelligent dynamic data perturbation OCDM encryption scheme based on cellular neural network and biological genetic encoding
Authors: Liu Xuanling , Liu Bo , Ren Jianxin , Mao Yaya , Chen Suaidong , Wan Yibin , Wu Xiangyu , Zhu Suiyao , Song Xiumin , Zhong Qing , Wu Yongfeng , Zhao Lilong , Sun Tingting , Ullah Rahat
Published: May 2022

In this paper, an intelligent dynamic perturbation orthogonal chirp division multiplexing (OCDM) encryption scheme based on cellular neural network and biological genetic encoding for seven-core optical fiber is proposed for the first time to our knowledge. In this scheme, chaotic sequences generated by cellular neural network are employed to construct six masking vectors to achieve six dimensions of ultra-high security encryption. The transmitted bit data is interleaved according to the DNA operation rules. The subcarrier frequency, symbol matrix, and time are scrambled. Because the selected encoding rule, decoding rule, key base sequence, subcarrier frequency, symbol matrix, and scrambling position of time all change dynamically, the robustness against malicious attack is enhanced. Simultaneously, OCDM technology is employed to optimize the system, which effectively improves the anti-interference ability and bit error performance of the system. A 70 Gb /s (7×10 Gb /s) encrypted OCDM signal transmission experiment is carried out on a 2 km 7-core fiber, and an orthogonal frequency division multiplexing (OFDM) signal is transmitted under the same conditions for comparison and verification. The results show that the key space of the newly proposed encryption scheme can reach 101170, and the receiver sensitivity of OCDM is 1.2 dB greater than that of OFDM when the bit error rate is 10−3. The scheme can improve the security of encrypted information and the performance of the system, which is very promising in the optical access network of the future.
Physics-informed neural network for polarimetric underwater imaging
Authors: Hu Haofeng , Han Yilin , Li Xiaobo , Jiang Liubing , Che Li , Liu Tiegen , Zhai Jingsheng
Published: May 2022

Utilizing the polarization analysis in underwater imaging can effectively suppress the scattered light and help to restore target signals in turbid water. Neural network-based solutions can also boost the performance of polarimetric underwater imaging, while most of the existing networks are pure data driven which suffer from ignoring the physical mode. In this paper, we proposed an effective solution that informed the polarimetric physical model and constrains into the well-designed deep neural network. Especially compared with the conventional underwater imaging model, we mathematically transformed the two polarization-dependent parameters to a single parameter, making it easier for the network to converge to a better level. In addition, a polarization perceptual loss is designed and applied to the network to make full use of polarization information on the feature level rather than on the pixel level. Accordingly, the network was able to learn the polarization modulated parameter and to obtain clear de-scattered images. The experimental results verified that the combination of polarization model and neural network was beneficial to improve the image quality and outperformed other existing methods, even in a high turbidity condition.
Fluorescence inhibition near spherical ENZ nanoparticles: competition between radiative and non-radiative processes
Authors: Atwi H. , Nicolas R. , Herro Z. , Vincent R.
Published: May 2022

In this work, we aim to study numerically the emission decay rate of a hybrid system combining a quantum emitter (QE) and an epsilon-near-zero (ENZ) spherical nanoparticle (SNP). Inspired by the peculiar behavior of ENZ materials and their high potential in developing unusual abilities in controlling the emission properties of QE. More specifically the control of fluorescence inhibition, or the amplification of the lifetime of the excited state. This can naturally find applications in quantum information storage for optical quantum memories based on light–atom interaction which naturally benefit from storage time control. We demonstrate that the key process in limiting fluorescence inhibition is the competition between inhibition of fluorescence from the radiative processes and energy dissipation due to the non-radiative channels. Furthermore, we illustrate that this balance can be shifted to optimize inhibition as function of the QE position. The optimization happens via SNP size control, material composition, and λ
ENZ
of the SNP. This detailed study introduces and paves the way for new research directions on the manipulation and optimization of QE properties in the vicinity of ENZ materials.
Ultrabroad Brillouin instantaneous frequency measurement with a designed linear system response
Authors: Yang Yonglan , Wang Xin , Xu Yuqiu , Liu Dunwei , Huo Juan , Zou Weiwen
Published: May 2022

We demonstrate an ultrabroad instantaneous frequency measurement (IFM) based on stimulated Brillouin scattering (SBS) with a designed linear system response. The linear system response is found to be the key factor that broadens the system bandwidth. It is realized by designing the sweeping method of frequency and amplitude of the local pump signal. With the improvement of linearity, the measurement error is decreased and the bandwidth of the SBS-based IFM is consequently enlarged. A Costas frequency modulated signal with an instantaneous bandwidth of 10.5 GHz is successfully measured by the designed system response. Further optimization of pump signal’s characteristics extends the system bandwidth to 14.5 GHz. The measurement error of a linear frequency modulated (LFM) signal ranging from 6 GHz to 20.5 GHz is less than 1% of the instantaneous bandwidth.
Laser-based selective BTEX sensing using deep neural networks
Authors: Mhanna Mhanna , Sy Mohamed , Arfaj Ayman , Llamas Jose , Farooq Aamir
Published: May 2022

A mid-infrared absorption-based laser sensor is developed for selective and simultaneous benzene, toluene, ethylbenzene, and xylenes (BTEX) measurements under ambient conditions. The sensor is based on a distributed feedback inter-band cascade laser emitting near 3.3 µm. Wavelength tuning and deep neural networks were employed to differentiate the broadband absorbance of BTEX species. The sensor was validated with gas mixtures and real-time measurements were demonstrated at a temporal resolution of 1 s. Minimum detection limits for BTEX in air are 8, 20, 5, and 46 ppm, respectively. This sensor can be utilized to monitor BTEX emissions in the petrochemical, rubber, and paint industries to avoid hazardous health effects.
Contribution of the collective electron dynamics to the polarization response of an atom subjected to intense IR and weak XUV pulses
Authors: Romanov A. A. , Silaev A. A. , Vvedenskii N. V. , Flegel A. V. , Frolov M. V.
Published: May 2022

We analyze the polarization response of a single Ne atom in an intense infrared (IR) laser field and weak extreme ultraviolet (XUV) isolated attosecond pulse (IAP). The analysis is based on the numerical solution of the time-dependent Kohn–Sham equations and the recently developed perturbation theory in the XUV field for an atom subjected to an intense IR field. In our numerical results, we observe a significant increase in the magnitude of the atomic polarization response at the frequencies near the carrier frequency of the IAP and associate it with XUV-induced collective dynamics contributing to the polarizability of Ne. The specific interference between IR- and XUV-induced channels is discussed, and its utilization for retrieving the phase of the generated harmonics in the IR field is suggested.
Anti-motion blur single-pixel imaging with calibrated radon spectrum
Authors: Yang Wei , Shi Dongfeng , Han Kai , Guo Zijun , Chen Yafeng , Huang Jian , Ling Hubin , Wang Yingjian
Published: May 2022

Single-pixel imaging (SPI), a novel computational imaging technique that has emerged in the past decades, can effectively capture the image of a static object by consecutively measuring light intensities from it. However, when SPI is applied to imaging the dynamic object, severe motion blur in the restored image tends to appear. In this Letter, a new SPI scheme is proposed to largely alleviate such a problem by leveraging a calibrated radon spectrum. Such a spectrum is obtained by translating the acquired one-dimensional projection functions (1DPFs) according to the positional relationship among the 1DPFs. Simulation and experimental results demonstrate that, without prior knowledge, our approach can effectively reduce motion blur and restore high-quality images of the fast-moving object. In addition, the proposed scheme can also be used for fast object tracking.
Femtosecond laser plane-by-plane inscribed ultrahigh-order fiber Bragg grating and its application in multi-wavelength fiber lasers
Authors: Luo Pengtao , Chen Fengyi , Li Xingyong , Zhu Wenhua , Bao Weijia , Wang Ruohui , Qiao Xueguang
Published: May 2022

We propose an ultrahigh-order fiber Bragg grating (UHO-FBG) containing dense resonants and its application as a novel filtering device in multi-wavelength lasers. The UHO-FBG is fabricated by femtosecond laser plane-by-plane direct inscription. Thanks to the plane-by-plane inscription, high-order Bragg resonances can be formed with multiple reflectance peaks of comparable reflectance in the range of the fiber operating bandwidth and without the transmission depression of long-period gratings in the transmission spectrum. We also experimentally demonstrate the use of UHO-FBG pairs in a distributed Bragg reflector laser, enabling the excitation of multi-wavelength lasers.
Sensitive and single-shot OH and temperature measurements by femtosecond cavity-enhanced absorption spectroscopy
Authors: Liu Ning , Zhong Hongtao , Chen Timothy Y. , Lin Ying , Wang Ziyu , Ju Yiguang
Published: May 2022

In many low-temperature plasmas (LTPs), the OH radical and temperature represent key properties of plasma reactivity. However, OH and temperature measurements in weakly ionized LTPs are challenging, due to the low concentration and short lifetime of OH and the abrupt temperature rise caused by fast gas heating. To address such issues, this Letter combined cavity-enhanced absorption spectroscopy (CEAS) with femtosecond (fs) pulses to enable sensitive single-shot broadband measurements of OH and temperature with a time resolution of ∼180 ns in LTPs. Such a combination leveraged several benefits. With the appropriately designed cavity, an absorption gain of ∼66 was achieved, enhancing the actual OH detection limit by ∼55× to the 1011 cm-3 level (sub-ppm in this work) compared with single-pass absorption. Single-shot measurements were enabled while maintaining a time resolution of ∼180 ns, sufficiently short for detecting OH with a lifetime of ∼100 μs. With the broadband fs laser, ∼34,000 cavity modes were matched with ∼95 modes matched on each CCD pixel bandwidth, such that fs-CEAS became immune to the laser-cavity coupling noise and highly robust across the entire spectral range. Also, the broadband fs laser allowed simultaneous sensing of many absorption features to enable simultaneous multi-parameter measurements with enhanced accuracies.
Meta-learning-based optical vector beam high-fidelity communication under high scattering
Authors: Chen Wenhui , He Hexiang , Lin Qian , Chen Weicheng , Su Zhikun , Cai Bingye , Zhu Wenguo , Zhang Li
Published: May 2022

While spatial structured light based free space optical communication provides high-bandwidth communication with broad application prospect, severe signal distortion caused by optical scattering from ambient microparticles in the atmosphere can lead to data degradation. A deep-learning-based adaptive demodulator has been demonstrated to resolve the information encoded in the severely distorted channel, but the high generalization ability for different scattering always requires prohibitive costs on data preparation and reiterative training. Here, we demonstrate a meta-learning-based auto-encoder demodulator, which learns from prior theoretical knowledge, and then training with only three realistic samples per class can rectify and recognize transmission distortion. By employing such a demodulator to hybrid vector beams, high fidelity communication can be established, and data costs are reduced when faced with different scattering channels. In a proof-of-principle experiment, an image with 256 gray values is transmitted under severe scattering with an error ratio of less than 0.05%. Our work opens the door to high-fidelity optical communication in random media environments.
On-chip multiple beam splitting assisted by bound states in the continuum
Authors: Wu Jiaju , Wei Qian , Wu Feng , Xu Xiaotian , Qi Xin , Guo ZhiWei , Sun Yong , Li Yunhui , Jiang Haitao , Chen Hong
Published: May 2022

Usually, on-chip beam splitting can be achieved by manipulating the in-plane iso-frequency curves (IFCs) of the structure, where the confinement of light along the out-of-plane direction is governed by total internal reflection. In this Letter, without needing a high-index dielectric background material for total internal reflection, we achieve on-chip beam splitting in a linear-crossing metamaterial (LCMM) mimicked by a two-dimensional photonic crystal (PhC) slab where the vertical confinement is enabled by a bound state in the continuum (BIC) and totally beyond the light cone. Particularly, the light propagating inside the LCMM can be flexibly controlled by the rotation angle of the rectangular silicon pillars in the PhC slab. On-chip triple beam splitting can further be designed by combining two kinds of LCMM with opposite rotation angles. Such light beam splitting beyond the light cone originates from the combined manipulation of the BIC and the spatial dispersion of LCMMs. Our work promotes the development of optical devices in integrated optics, such as on-chip focusing, switching, and (de)multiplexing.
Bound valley edge states in the continuum
Authors: Feng Yadian , Zhang Zhanyuan , Qin Feifei , Lan Zhihao , Sha Wei E. I. , Xu Yi
Published: May 2022

Topological valley photonics provides a unique way to manipulate the flow of light. In general, valley edge states that exhibit unidirectional propagation and are immune to defects and disorders could be realized at the interface between two valley photonic crystals with opposite valley Chern numbers. Herein, by merging the physics of valley edge states and bound states in the continuum, we propose and numerically demonstrate a novel, to the best of our knowledge, concept of edge states termed bound valley edge states in the continuum, which enjoys the topological features of valley edge states, such as, unidirectional propagation and immunity to disorders, but are formed at the interface between air and a single valley photonic crystal. Our results not only provide an effective way to reduce the size of valley photonic structures but also facilitate new applications where the proposed concept of bound valley edge states in the continuum could be exploited for optical sensing and unidirectional waveguiding.
Integration in the C-band between quantum key distribution and the classical channel of 25 dBm launch power over multicore fiber media
Authors: Geng Jia-Qi , Fan-Yuan Guan-Jie , Li Kang-Jie , Tang Ming , Wang Shuang , He De-Yong , Chen Wei , Yin Zhen-Qiang , Guo Guang-Can , Han Zheng-Fu
Published: May 2022

The quantum–classical coexistence can be implemented based on wavelength division multiplexing (WDM), but due to Raman noise, the wavelength spacing between quantum and classical signals and launch power from classical channels are restricted. Space division multiplexing (SDM) can now be availably achieved by multicore fiber (MCF) to reduce Raman noise, thereby loosening the restriction for coexistence in the same band and obtaining a high communication capacity. In this paper, we realize the quantum–classical coexistence over a 7-core MCF. Based on the SDM, the highest launch power of 25 dBm is achieved which has been extended nearly 19 times in previous work. Moreover, both the quantum and classical channels are allocated in the C-band and the minimum wavelength spacing between them is only 1.6 nm. The coexistence system eliminates the need for adding a narrowband filter.