bluuebunny/crossref_metadata_2025 huggingface dataset:
Femtosecond Laser Induced Site-specific Reduction of Silver Salt and Graphene Oxide Films
Authors: Joshi Sarika , Singh Gaurav Pratap , Joseph Haritha , Jaiswal Arun , Yadav Dharamveer , Saxena Sumit , Shukla Shobha
Published: July 2023

Simultaneous silver salt reduction and deposition at specific sites of graphene oxide films by femtosecond laser irradiation is achieved and Raman analysis corresponding to varying concentration of silver salt loading is investigated.
Scalable Laser Integration on Thin-film Lithium Niobate Platform
Authors: Shams-Ansari Amirhassan , Grant Hannah R. , Musolf Juergen , Renaud Dylan , He Lingyan , Cheng Rebecca , Barton David , MacFarlane Jessica , Morrison Gordon , Zhang Mian , Johansson Leif , Lončar Marko
Published: July 2023

We demonstrate a technique allowing scalable integration of III-V lasers on thin-film lithium niobate platform. Our method relies on an unconventional growth of the III-V epitaxial layer such that the n-layer ends on the top.
Energy scaling of the single-cycle pulse generation based on DC-OPA
Authors: Xu Lu , Takahashi Eiji J.
Published: July 2023

Based on the dual-chirped optical parametric amplification scheme, a 61 mJ, over one-octave bandwidth, 10 Hz, carrier-to-envelope phase (CEP) stable laser pulses centered at 2.3 μm is achieved by employing BiB3O6 crystals and MgO:LiNbO3 crystals. After compression, the output pulse duration is down to 8.7 fs (1.1 cycles @ 2.3 μm), which results in a peak power of 7 TW.
Approaching the TW-regime with mJ-class picosecond pulses post-compressed to 13 fs
Authors: Rajhans Supriya , Escoto Esmerando , Khodakovskiy Nikita , Velpula Praveen Kumar , Farace Bonaventura , Shalloo Rob , Kang Keekon , Põder Kristjan , Osterhoff Jens , Leemans Wim P. , Hartl Ingmar , Heyl Christoph M.
Published: July 2023

We demonstrate efficient post compression of 9.45 mJ, 1.2 ps pulses to 13 fs at 1 kHz repetition rate using a two stage gas filled multi pass cell system reaching near terawatt peak power.
Highly efficient blue and green VCSELs with AlInN/GaN bottom DBRs
Authors: Terao Kenichi , Nagai Hitoshi , Tsukayama Kazutaka , Ohara Takashi , Hara Yoshihiro , Shimazu Ryoma , Masui Shingo , Yanamoto Tomoya , Nagahama Shin-ichi
Published: July 2023

We report milliwatt-class nitride blue and green VCSELs with hybrid DBR structure. The wall-plug efficiency of 18.5% and 3.7% were achieved for the blue and green VCSELs, respectively. Highly reliable operation was also demonstrated.
Metalens-Integrated Optical Phased Array for Optical Manipulation with Wavelength Tuning
Authors: Lee Woo-Bin , Bhandari Bishal , Li Hongliang , Choi Duk-Yong , Lee Sang-Shin
Published: July 2023

We have proposed a metalens-integrated optical phased array, enabling on-chip based optical manipulating with wavelength tuning. The movement of the focal point is demonstrated while there are no moving parts.
Nonreciprocal vortex conversion and frequency shifting using light-driven chiral flexural waves
Authors: Zeng Xinglin , Russell Philip St.J. , Stiller Birgit
Published: July 2023

We report nonreciprocal vortex conversion and frequency shifting via cork-screw-like chiral flexural phonons induced by forward Brillouin scattering in chiral photonic crystal fibre. A nonreciprocity factor greater than >13 dB is achieved.
All-Optical Magnetization Reversal in Arbitrary Geometries using Metasurfaces
Authors: Khalid Muhammad Waleed , Ha Jeongho , Hemayat Saeed , el Hadri Mohammed Salah , Fullerton Eric E. , Ndao Abdoulaye
Published: July 2023

We report and experimentally demonstrate a monolithic multilayer nanostructure capable of achieving high speed, and high density of optical helicity-dependent mag-netization switching using femtosecond circularly polarized optical pulses from a metasurface.
Large Dispersion Silicon Bragg Grating with Integrated Phase Shifter Array
Authors: Stern Brian , Chen Haoshuo , Kim Kwangwoong , Fontaine Nicolas K.
Published: July 2023

We demonstrate a silicon photonic Bragg grating waveguide with a large dispersion of ‑146 ps/nm and 171 GHz bandwidth. Using an integrated phase shifter array, the grating is tuned to reduce ripple nearly threefold.
Monolithically-integrated femtosecond optical parametric oscillators
Authors: Jornod Nayara , Jankowski Marc , Krüger Léonard M. , Wittwer Valentin J. , Modsching Norbert , Langrock Carsten , Phillips Christopher R. , Keller Ursula , Südmeyer Thomas , Fejer M. M.
Published: July 2023

We demonstrate synchronously-pumped femtosecond optical parametric oscillators in integrated photonics. These monolithic 10-GHz cavities operate stably without active locking and exhibit many operating regimes observed in free-space OPOs: nondegenerate operation, box-pulsing, and quadratic bright-dark solitons.
Widely Tunable, Low-Threshold Raman Laser Based on Dispersion-Managed Lithium Niobate Microresonator
Authors: Zhao Yanjing , Liu Xiaoyue , Yvind Kresten , Cai Xinlun , Pu Minhao
Published: July 2023

We achieve sub-milliwatt-threshold Raman lasing in a high-Q thin-film lithium niobate microresonator and demonstrate a tuning range of about 300 nm by sweeping the pump wavelength only within the telecom C- and L-band.
A High-Resolution Photonic Integrated High Q Microresonator Based Accelerometer
Authors: Tian Hao , Raja Arslan S. , Attanasio Alaina G. , Liu Junqiu , Wang Rui N. , Siddharth Anat , Kippenberg Tobias J. , Bhave Sunil A.
Published: July 2023

We demonstrated a packaged optomechanical accelerometer with resolution of 850ng. The resonance of a 4 million Q Si3N4 microring resonator is modulated by the stress in springs of a released milligram proof mass upon acceleration.
Wavefront Characterization of a Gaussian Beam after Propagation through Optical Turbulence Generated by Rayleigh-Bénard Convection
Authors: O’Malley Owen M. , Avramov-Zamurovic Svetlana , Ferlic Nathaniel A. , Mullen Linda J. , Judd K. Peter
Published: July 2023

A Gaussian beam is propagated through a water tank containing Rayleigh-Bénard convection. The beam wavefront is measured using a Shack-Hartmann sensor to obtain optical wavefront statistics for characterization of the random phase perturbations.
Label-Free Three-Photon Deep Imaging with High Power Femtosecond Yb-fiber Laser
Authors: Fernández Alma , Classen Anton , Josyula Nitya Kalyani , Straight Paul , Verhoef Aart
Published: July 2023

We demonstrate simultaneous multicolor two- and three-photon imaging of bacterial filaments using a single high-power femtosecond Yb-fiber laser. Our experiments demonstrate the superior signal-to-background ratio obtainable with three-photon imaging deep below the sample surface.
Field Demonstration of Low-Latency Massively Parallel Communication with Microresonator Frequency Comb
Authors: Tanikawa Koya , Fujii Shun , Tanaka Shuya , Tasaka Shun , Wada Koshiro , Kogure Soma , Kumazaki Hajime , Kawanishi Satoki , Tanabe Takasumi
Published: July 2023

We demonstrated low-latency optical transmission with a microresonator frequency comb using a 9-km optical fiber in a metropolitan area. The delay time of the entire system, excluding the transmission fiber, was only 3.1 μs.
Topological Photonic Circuit for Beam Splitting, Routing, and Far Field Steering
Authors: Wu Tianwei , Li Yankun , Feng Xilin , Wu Shuang , Gao Zihe , Feng Liang
Published: July 2023

Nonmechanical robust far field beam scanning is highly demanded for integrated photonics. Here we report an on-chip optical beam splitting, routing, and wavelength-sensitive far field steering enabled by a topological photonic integrated circuit.
WDM Transmission via High-Power Fully-Integrated Kerr Frequency Combs
Authors: Gil-Molina Andres , Antman Yair , Westreich Ohad , Ji Xingchen , Shin Min Chul , Bhatt Gaurang R. , Datta Ipshita , Kim Bok Young , Okawachi Yoshitomo , Gaeta Alexander L. , Lipson Michal
Published: July 2023

We demonstrate high-power, fully-integrated Kerr frequency combs by self-injection locking multimode gain chips with silicon-nitride resonators. We demonstrate 25 comb lines > 100 μW with 200 kHz linewidth, and OOK modulation at 12.5 Gb/s.
Bottom-up Fabricated Barium Titanate Nonlinear Photonic Crystal
Authors: Talts Ülle-Linda , Weigand Helena , Vogler-Neuling Viola , Saerens Grégoire , Benedek Peter , Winiger Joel , Wood Vanessa , Leuthold Jürg , Grange Rachel
Published: July 2023

Sol-gel derived barium titanate photonic crystals with a resonance centered at 780 nm were enabled by soft-nanoimprint lithography. The increased light-matter interaction at resonance is shown by 15 times enhancement of the second harmonic generation.
All-Optical Spiking Membrane III-V Laser on Si
Authors: Diamantopoulos Nikolaos-Panteleimon , Yamaoka Suguru , Fujii Takuro , Nishi Hidetaka , Segawa Toru , Matsuo Shinji
Published: July 2023

We present an all-optical photonic spiking neuron based on a membrane laser on silicon with optical feedback. Ultrafast dynamics with ~200-ps refractory periods using 10-GHz signals are demonstrated, at a laser-energy cost of ~10 pJ/spike.
FWM-to-OPA Transition and Signal Power Increase in FWM
Authors: Akasaka Youichi , Palacharla Paparao
Published: July 2023

We examined the transition from four-wave mixing to parametric amplification. The signal intensity can be increased with smaller noise in four-wave mixing region than in optical parametric amplification.
Visible Lithium Niobate Integrated Modulators for Classical and Quantum Technologies
Authors: Renaud Dylan , Assumpcao Daniel , Joe Graham , Shams-Ansari Amirhassan , Zhu Di , Hu Yaowen , Sinclair Neil , Loncar Marko
Published: July 2023

We demonstrate visible sub-1 V amplitude and phase modulators in thin-film lithium niobate. We use these devices to demonstrate EO frequency shifting of pulsed light over 7 times the intrinsic pulse bandwidth.
Two-Octave Frequency Comb from a Nanophotonic Parametric Oscillator
Authors: Sekine Ryoto , Gray Robert , Ledezma Luis , Zhou Selina , Guo Qiushi , Marandi Alireza
Published: July 2023

We demonstrate a synchronously pumped OPO in nanophotonic lithium nio-bate with a 4-ns-roundtrip cavity generating two octaves of continuous and coherent spec-trum from the visible to mid-IR with only 126 fJ of pump energy.
Optimizing Laser Conversion in Microresonator Optical-Parametric Oscillation
Authors: Liu Haixin , Brodnik Grant M. , Zang Jizhao , Carlson David R. , Black Jennifer A. , Papp Scott B.
Published: July 2023

We explore pump-laser conversion to the unit boundary, leveraging photonic crystal microresonators for universal phase-matching and on-chip reflectors to boost efficiency. Our experiments demonstrate high laser conversion efficiency and output power with integrated, wavelength-diverse lasers.
Frequency Translation Using Backward-Wave Spontaneous Parametric Downconversion
Authors: Kuo Paulina S. , Reddy Dileep V. , Verma Varun , Nam Sae Woo , Zukauskas Andrius , Canalias Carlota
Published: July 2023

We experimentally investigate using backward-wave spontaneous parametric downconversion for frequency translation, where spectral characteristics of the pump wave are transferred to the signal wave.
Frequency noise metrology of SiN microresonators with Qs of 100 million at the thermodynamical bounds
Authors: Aldhafeeri Alwaleed , Yerebakan Talha , Jang Yoon-Soo , Tran Minh A. , Komljenovic Tin , Wong Chee Wei
Published: July 2023

The thermorefractive noise of a high-quality factor silicon nitride resonator is measured in a vacuum chamber using Hz-linewidth laser. This scheme allows noise measurement without being concerned about laser frequency noise or environmental effects
Low Repetition Rate Mode-Locked Laser on a Commercial Foundry Low-Index Photonic Platform
Authors: Poelman Stijn , Cuyvers Stijn , Vissers Ewoud , De Witte Jasper , Haq Bahawal , Hermans Artur , Picqué Nathalie , Roelkens Gunther , Kuyken Bart
Published: July 2023

We demonstrate a heterogeneously integrated III-V-on-silicon-nitride mode-locked laser with 710 MHz repetition rate. A versatile two-step micro-transfer printing approach is employed to enable low-loss integration on a commercial foundry low-index photonic platform.
Self-Heating Based Locking of a Laser to a High-QSi3N4 Microcavity
Authors: Dacha Sai Kanth , Zhao Yun , Ji Xingchen , Beals Garrett J. , Sanyal Swarnava , Lipson Michal , Gaeta Alexander L.
Published: July 2023

We demonstrate locking of a laser to an external silicon nitride microcavity resonance without the use of a photodiode. This is achieved by indirectly measuring changes in microcavity temperature that occur during resonant power buildup.
Wafer-level fabrication of Fabry-Pérot resonators with finesse exceeding one million
Authors: Jin Naijun , Liu Yifan , McLemore Charles A. , Luo Yizhi , Mason David , Kharel Prashanta , Diddams Scott A. , Quinlan Franklyn , Rakich Peter
Published: July 2023

We demonstrate a wafer-level fabrication technique for high-finesse Fabry-Pérot optical resonators based on reflow and optical contact bonding. These resonators have finesse exceeding one million at 1550 nm and can be readily used as reference cavities.
Active Tuning of the Microresonator Coupling Condition with Coupled Rings
Authors: Zhao Yun , McNulty Karl J. , Lipson Michal , Gaeta Alexander L.
Published: July 2023

We demonstrate a novel approach to actively and continuously tune the coupling condition of microresonators. Our approach allows for wavelength-dependent coupling and dispersion modification after fabrication.
Tailoring a narrow phasematching bandwidth with a resonant quantum pulse gate
Authors: Echeverría-Oviedo Dana , Stefszky Michael , Gil-López Jano , Brecht Benjamin , Silberhorn Christine
Published: July 2023

The performance of the quantum pulse gate (QPG) is limited by its phase-matching bandwidth (PM-BW). We propose a resonant QPG comprised of coupled cavities, which exhibits MHz PM-BW and yields improved resolution in metrology applications.
Optical printed circuit boards with multimode polymer waveguides and pluggable connectors for high-speed optical interconnects
Authors: Shi Ying , Liu Xu , Ma Lin , Immonen Marika , Zhu Longxiu , He Zuyuan
Published: July 2023

We demonstrate the development of optical printed circuit boards (OPCBs) containing multimode polymer waveguides and pluggable optical connectors. The basic optical characteristics of the PCB-embedded waveguides, waveguide connectors, and high-speed performance were comprehensively evaluated. The fabricated OPCB comprises eight electrical layers and one optical layer. Waveguides are terminated at both ends with MT/MPO connectors. The optical channels comprising 10 cm-long waveguides embedded in OPCBs with two connectors show an average insertion loss of 6.42 dB. The resulting coupling loss is 0.77 dB per interface, which is very low and to our knowledge is among the lowest reported to date for waveguides embedded in rigid PCBs. 30 Gbps per channel NRZ data transmission was demonstrated with a measured waveguide bandwidth of 23 GHz × m, which gives a possible data traffic of 720 Gb/s for such 24-channel parallel optical link. Our efforts lay the foundation for the further development of OPCBs with higher performance.
Enhanced optical forces on coupled chiral particles at arbitrary order exceptional points
Authors: Zhang Chengzhi , Cheng Yuqiong , Wang Shubo
Published: July 2023

Exceptional points (EPs)—non-Hermitian degeneracies at which eigenvalues and eigenvectors coalesce—can give rise to many intriguing phenomena in optical systems. Here, we report a study of the optical forces on chiral particles in a non-Hermitian system at EPs. The EPs are achieved by employing the unidirectional coupling of the chiral particles sitting on a dielectric waveguide under the excitation of a linearly polarized plane wave. Using full-wave numerical simulations, we demonstrate that the structure can give rise to enhanced optical forces at the EPs. Higher order EPs in general can induce stronger optical forces. In addition, the optical forces exhibit an intriguing “skin effect”: the force approaches the maximum for the chiral particle at one end of the lattice. The results contribute to the understanding of optical forces in non-Hermitian systems and can find applications in designing novel optical tweezers for on-chip manipulations of chiral particles.
Multi-dimensional multiplexed, tri-comb and quad-comb generation from a bidirectional mode-locked fiber laser
Authors: Chen Jie , Wang Xiaoyu , Fang Xiaopeng , Zhao Xin , Zheng Zheng
Published: July 2023

Tri-comb and multi-comb techniques could enable many advanced measurement applications beyond the reach of traditional dual-comb schemes. However, the sophisticated and bulky control systems of the conventional schemes based on three comb lasers render them impractical for many potential applications. Like their dual-comb counterparts, tri-comb and multi-comb lasers are being investigated as attractive alternatives. In contrast to previous dual-comb lasers using only one multiplexing dimension of optical pulses, this work simultaneously leverages multiplexing methods in three physical dimensions, i.e. wavelength, polarization, and direction, to generate triple to quadruple asynchronous pulse trains in a bidirectional mode-locked fiber laser. Because of the unique cavity structure studied here, both wavelength-multiplexed and polarization-multiplexed dual-comb generation from a completely shared-cavity and wavelength/polarization-multiplexed multi-comb generation from a bidirectional partially shared-cavity are achieved. Good relative stability among the generated combs of the fiber laser is demonstrated, as well as proof-of-concept dual-comb spectroscopy measurements, which validates the mutual coherence between the combs. The analysis of the experimental results further reveals interesting performance comparisons between combs from different multiplexing schemes, thanks to the special laser design used here that allows a side-by-side dual-comb demonstrations from different combinations of outputs from the same laser. Our investigation could facilitate multi-comb generation based on one light source for field-deployable multi-comb applications.
On-chip long-wavelength infrared polarimeter for full-Stokes polarization detection
Authors: Shen Jinyong , Zhou Jing , Zhu Tianyun , Deng Jie , Wang Bo , Jing Wenji , Ma Jiajun , Qin Xinyue , Liu Huipeng , Li Jiajun , Chen Xiaoshuang , Lu Wei
Published: July 2023

Polarization detection is a critical technique in various research and application fields, especially in the long-wavelength infrared regime for target discrimination from complex backgrounds. With the trend of miniaturization and integration, on-chip full-Stokes polarimeters are eagerly pursued. However, how to achieve efficient linear and circular polarimetry simultaneously on the same detection material chip with sufficient polarization extinction ratios and responsivities still remains a challenge. In this work, we propose an on-chip long-wavelength infrared full-Stokes polarimeter based on the integration of anisotropic and twisted metamaterials on the same quantum well material chip. The device consists of six subpixels with different principle detection polarization states. Based on the dual polarization selection by the structure and the detection material, the linear polarization extinction ratio exceeds 106 and the circular polarization extinction ratio reaches 150. In addition, the absorptance of the detection material is enhanced by more than 16 times. Through simple subtracting and normalization operations on the photocurrents of the subpixels, the Stokes parameters are obtained with small root mean square errors. The device performance remains at a high level over the incident angle range of ±5°. This work points out a promising way for on-chip long-wavelength infrared full-Stokes detection. The device architecture is compatible with focal plane arrays.
Developing digital tools for health surveys in low- and middle-income countries: Comparing findings of two mobile phone surveys with a nationally representative in-person survey in Bangladesh
Authors: Kibria Gulam Muhammaed Al , Ahmed Saifuddin , Khan Iqbal Ansary , Fernández-Niño Julián A. , Vecino-Ortiz Andres , Ali Joseph , Pariyo George , Kaufman Michelle , Sen Aninda , Basu Sunada , Gibson Dustin
Published: July 2023

Non-communicable disease (NCD) risk factor data from low- and middle-income countries (LMICs) are inadequate, mostly due to the cost and burden of collecting in-person population-level estimates. High-income countries regularly use phone-based surveys, and with increasing mobile phone subscription in developing countries, mobile phone surveys (MPS) could complement in-person surveys in LMICs. We compared the representativeness and prevalence estimates of two MPS (i.e., interactive voice response (IVR) and computer-assisted telephone interview (CATI)) with a nationally representative household survey in Bangladesh–the STEPwise approach to NCD risk factor surveillance (STEPs) 2018. This cross-sectional study included 18-69-year-old respondents. CATI and IVR recruitments were done by random digit dialing, while STEPs used multistage cluster sampling design. The prevalence of NCD risk factors related to tobacco, alcohol, diet, and hypertension was reported and compared by prevalence differences (PD) and prevalence ratios (PR). We included 2355 (57% males), 1942 (62% males), and 8185 (47% males) respondents in the CATI, IVR, and STEPs, respectively. CATI (28%) and IVR (52%) had a higher proportion of secondary/above-educated people than STEPs (13%). Most prevalence estimates differed by survey mode; however, CATI estimates were closer to STEPs than IVR. For instance, in CATI, IVR, and STEPs, respectively, the prevalence was 21.4%, 17.9%, and 23.5% for current smoking; and 1.6%, 2.2%, and 1.5% for alcohol drinking in past month. Compared to STEPs, the PD ranged from ‘-56.6% to 0.4%’ in CATI and ‘-41.0% to 8.4%’ in IVR; the PR ranged from ‘0.3 to 1.1’ in CATI and ‘0.3 to 1.6’ in IVR. There were some differences and some similarities in NCD indicators produced by MPS and STEPs with differences likely due to differences in socioeconomic characteristics between survey participants.
Prevalence of blood and skin trypanosomes in domestic and wild fauna from two sleeping sickness foci in Southern Cameroon
Authors: Magang Eugenie Melaine Kemta , Kamga Rolin Mitterran Ndefo , Telleria Jenny , Tichit Magali , Crouzols Aline , Kaboré Jacques , Hardy David , Bouaka Calmes Ursain Tsakeng , Jamonneau Vincent , Rotureau Brice , Kuete Victor , Bart Jean-Mathieu , Simo Gustave
Published: July 2023

Although studies on African Trypanosomiases revealed a variety of trypanosome species in the blood of various animal taxa, animal reservoirs of Trypanosoma brucei gambiense and anatomical niches such as skin have been overlooked in most epidemiological settings. This study aims to update epidemiological data on trypanosome infections in animals from human African trypanosomiasis (HAT) foci of Cameroon. Blood and skin snips were collected from 291 domestic and wild animals. DNA was extracted from blood and skin snips and molecular approaches were used to identify different trypanosomes species. Immunohistochemical analyses were used to confirm trypanosome infections in skin snips. PCR revealed 137 animals (47.1%) with at least one trypanosome species in the blood and/or in the skin. Of these 137 animals, 90 (65.7%) and 32 (23.4%) had trypanosome infections respectively in the blood and skin. Fifteen (10.9%) animals had trypanosome infections in both blood and skin snip. Animals from the Campo HAT focus (55.0%) were significantly (X2 = 17.6; P< 0.0001) more infected than those (29.7%) from Bipindi. Trypanosomes of the subgenus Trypanozoon were present in 27.8% of animals while T. vivax, T. congolense forest type and savannah type were detected in 16.5%, 10.3% and 1.4% of animals respectively. Trypanosoma b. gambiense infections were detected in the blood of 7.6% (22/291) of animals. No T. b. gambiense infection was detected in skin. This study highlights the presence of several trypanosome species in the blood and skin of various wild and domestic animals. Skin appeared as an anatomical reservoir for trypanosomes in animals. Despite methodological limitations, pigs, sheep, goats and wild animals were confirmed as potential reservoirs of T. b. gambiense. These animal reservoirs must be considered for the designing of control strategies that will lead to sustainable elimination of HAT.
Soliton solutions for the Zoomeron model applying three analytical techniques
Authors: Ullah Mohammad Safi , Mostafa Md. , Ali M. Zulfikar , Roshid Harun-Or , Akter Mahinur
Published: July 2023

The Zoomeron equation is used in various categories of soliton with unique characteristics that arise in different physical phenomena, such as fluid dynamics, laser physics, and nonlinear optics. To achieve soliton solutions for the Zoomeron nonlinear structure, we apply the unified, the Kudryashov, and the improved Kudryashov techniques. We find periodic, breather, kink, anti-kink, and dark-bell soliton solutions from the derived optical soliton solutions. Bright, dark, and bright-dark breather waves are also established. Finally, some dynamic properties of the acquired findings are displayed in 3D, density, and 2D views.
Organisation, staffing and resources of critical care units in Kenya
Authors: Mwangi Wambui , Kaddu Ronnie , Njoki Muiru Carolyne , Simiyu Nabukwangwa , Patel Vishal , Sulemanji Demet , Otieno Dorothy , Okelo Stephen , Chikophe Idris , Pisani Luigi , Dona Dilanthi Priyadarshani Gamage , Beane Abi , Haniffa Rashan , Misango David , Waweru-Siika Wangari ,   for the Kenya Critical Care Registry Investigators
Published: July 2023

Objective

To describe the organisation, staffing patterns and resources available in critical care units in Kenya. The secondary objective was to explore variations between units in the public and private sectors.

Materials and methods

An online cross-sectional survey was used to collect data on organisational characteristics (model of care, type of unit, quality- related activities, use of electronic medical records and participation in the national ICU registry), staffing and available resources for monitoring, ventilation and general critical care.

Results

The survey included 60 of 75 identified units (80% response rate), with 43% (n = 23) located in government facilities. A total of 598 critical care beds were reported with a median of 6 beds (interquartile range [IQR] 5–11) per unit, with 26% beds (n = 157) being non functional. The proportion of ICU beds to total hospital beds was 3.8% (IQR 1.9–10.4). Most of the units (80%, n = 48) were mixed/general units with an open model of care (60%, n = 36). Consultants-in-charge were mainly anesthesiologists (69%, n = 37). The nurse-to-bed ratio was predominantly 1:2 with half of the nurses formally trained in critical care. Most units (83%, n = 47) had a dedicated ventilator for each bed, however 63% (n = 39) lacked high flow nasal therapy. While basic multiparametric monitoring was ubiquitous, invasive blood pressure measurement capacity was low (3% of beds, IQR 0–81%), and capnography moderate (31% of beds, IQR 0–77%). Blood gas analysers were widely available (93%, n = 56), with 80% reported as functional. Differences between the public and private sector were narrow.

Conclusion

This study shows an established critical care network in Kenya, in terms of staffing density, availability of basic monitoring and ventilation resources. The public and private sector are equally represented albeit with modest differences. Potential areas for improvement include training, use of invasive blood pressure and functionality of blood gas analysers.
Adapted tissue assay for the assessment of ileal granulocyte degranulation following in ovo inoculation with select bacteria or coccidial challenge in chickens
Authors: Duff Audrey F. , Chasser Kaylin M. , McGovern Kate E. , Trombetta Michael , Bielke Lisa R.
Published: July 2023

A previously described heterophil degranulation assay was adapted for use with ileal mucosal tissue via quantification of β-D-glucuronidase and assay end product 4-methylumbelliferone (4-MU). Three initial experiments evaluated the effect ofin ovoinoculations ofCitrobacter freundii(CF) or mixed lactic acid bacteria (LAB) on ileal granulocyte degranulation. Inoculations were administered on embryonic d18, body weights (BW) were recorded on day of hatch (DOH) and d10 to calculate body weight gain (BWG), and ileal mucosal scrapings were collected on DOH or d10 for the 4-MU assay. In all experiments, treatments were statistically analyzed relative to control groups. Treatments minimally affected BWG in allin ovoexperiments (p> 0.05) relative to respective control groups. Similarly, ileal degranulation inin ovotreatments did not statistically differ (p> 0.05). Based on BWG,in ovotreatments may have induced low-level inflammation unable to elicit detectable changes via the 4-MU assay. Four subsequent experiments were conducted to evaluate effects ofEimeria maxima(EM) on ileal degranulation. Treatments included non-inoculated controls and low, medium, or high EM infection. Across all four experiments, final BW or BWG over the inoculation period were suppressed (p< 0.05) in EM groups relative to respective controls with the exception of EM-low (p= 0.094) and EM-medium (p= 0.096) in one trial. Ileal mucosal scrapings for the 4-MU assay were collected on day of peak lesions. Resulting values were reduced (p< 0.05) for EM treated birds in three experiments with the exception of EM-medium (p= 0.247). No differences were observed in one experiment (p= 0.351), which may have been attributed to a variation in strain of infectingEimeria. Although refinement for low level inflammation is warranted, results indicate successful adaptation of the 4-MU assay for use with intestinal tissue during significant gastrointestinal inflammation.
Evaluation of disinfection methods for personal protective equipment (PPE) items for reuse during a pandemic
Authors: Archer John , Mikelonis Anne , Wyrzykowska-Ceradini Barbara , Morris Eric , Sawyer Jonathan , Chamberlain Timothy , Abdel-Hady Ahmed , Monge Mariela , Touati Abderrahmane
Published: July 2023

The COVID-19 pandemic resulted in many supply chain issues, including crippling of essential personal protective equipment (PPE) needed for high-risk occupations such as those in healthcare. As a result of these supply chain issues, unprecedented crisis capacity strategies were implemented to divert PPE items such as filtering facepiece respirators (FFRs, namely N95s) to those who needed them most for protection. Large-scale methods for decontamination were used throughout the world to preserve these items and provided for their extended use. The general public also adopted the use of non-specialized protective equipment such as face coverings. So, the need for cleaning, decontamination, or disinfection of these items in addition to normal clothing items became a necessary reality. Some items could be laundered, but other items were not appropriate for washing/drying. To fill research gaps in small-scale, non-commercial cleaning and disinfection, this bench-scale research was conducted using small coupons (swatches) of multiple PPE/barrier protection materials inoculated with virus (non-pathogenic bacteriophages Phi6 and MS2) and tested against a range of decontamination methods including bleach-, alcohol- and quaternary ammonium compound (QAC)-based liquid sprays, as well as low concentration hydrogen peroxide vapor (LCHPV) and bench-scale laundering. In general, non-porous items were easier to disinfect than porous items, and the enveloped virus Phi6 was overall easier to inactivate than MS2. Multiple disinfection methods were shown to be effective in reducing viral loads from PPE coupons, though only laundering and LCHPV were effective for all materials tested that were inoculated with Phi6. Applications of this and follow-on full-scale research are to provide simple effective cleaning/disinfection methods for use during the current and future pandemics.
Deliberative panels as a source of public knowledge: A large-sample test of the Citizens’ Initiative Review
Authors: Gastil John , Ársælsson Kristinn Már , Knobloch Katherine R. , Brinker David L. , Richards Robert C. , Reedy Justin , Burkhalter Stephanie
Published: July 2023

Evolving US media and political systems, coupled with escalating misinformation campaigns, have left the public divided over objective facts featured in policy debates. The public also has lost much of its confidence in the institutions designed to adjudicate those epistemic debates. To counter this threat, civic entrepreneurs have devised institutional reforms to revitalize democratic policymaking. One promising intervention is the Citizens’ Initiative Review (CIR), which has been adopted into law in Oregon and tested in several other states, as well as Switzerland and Finland. Each CIR gathers a demographically stratified random sample of registered voters to form a deliberative panel, which hears from pro and con advocates and neutral experts while assessing the merits of a ballot measure. After four-to-five days of deliberation, each CIR writes an issue guide for voters that identifies key factual findings, along with the most important pro and con arguments. This study pools the results of survey experiments conducted on thirteen CIRs held from 2010 to 2018, resulting in a dataset that includes 67,120 knowledge scores collected from 10,872 registered voters exposed to 82 empirical claims. Analysis shows that reading the CIR guide had a positive effect on voters’ policy knowledge, with stronger effects for those holding greater faith in deliberation. We found little evidence of directional motivated reasoning but some evidence that reading the CIR statement can spark an accuracy motivation. Overall, the main results show how trust in peer deliberation provides one path out of the maze of misinformation shaping voter decisions during elections.
Perception, attitudes, and knowledge on infestation and management of bed bugs in major cities of Indonesia: A cross-sectional online survey
Authors: Meisyara Dita , Guswenrivo Ikhsan , Veera Singham G.
Published: July 2023

The resurgence of bed bugs is a global phenomenon, but until now reports on bed bug infestations in Indonesia are rare. The success of bed bug control is affected by people’s knowledge and awareness. Stigma against bed bugs in Indonesia discourages the public from reporting infestations and therefore knowledge of their impact on public health is scarce. Herein, this study investigates the public’s perception, attitudes, and knowledge on bed bug-related issues in several major cities in Indonesia through an online survey. Despite low case reports, three in five respondents (n = 600) have encountered bed bugs at least once; mostly in their homes (74.1%). Approximately half of the respondents correctly identified bed bugs, whereas mites were often misidentified for bed bugs (26.3%). Bite marks were not a useful indicator for detecting bed bugs. We found age, gender, and level of education affects the public’s perception toward various bed bug-related issues. Regarding bed bug treatment, above 50% respondents are unaware of the availability of bed bug-specific insecticidal products and are unwilling to pay pest management professionals to control infestation. This study provides the first overview of the public’s awareness and perception of bed bug infestations in some major cities of Indonesia, which can be useful for designing public health policies for bed bug management. The reported data represents the perspectives of online users, most likely from metropolitan regions. A bigger monitoring program encompassing pest professionals and hospitality businesses would give a more thorough overview of the bed bug impact in Indonesia.
The assessment of molecular dynamics results of three-dimensional RNA aptamer structure prediction
Authors: Ropii Bejo , Bethasari Maulidwina , Anshori Isa , Koesoema Allya Paramita , Shalannanda Wervyan , Satriawan Ardianto , Setianingsih Casi , Akbar Mohammad Rizki , Aditama Reza
Published: July 2023

Aptamers are single-stranded DNA or RNA that bind to specific targets such as proteins, thus having similar characteristics to antibodies. It can be synthesized at a lower cost, with no batch-to-batch variations, and is easier to modify chemically than antibodies, thus potentially being used as therapeutic and biosensing agents. The current method for RNA aptamer identification in vitro uses the SELEX method, which is considered inefficient due to its complex process. Computational models of aptamers have been used to predict and study the molecular interaction of modified aptamers to improve affinity. In this study, we generated three-dimensional models of five RNA aptamers from their sequence using mFold, RNAComposer web server, and molecular dynamics simulation. The model structures were then evaluated and compared with the experimentally determined structures. This study showed that the combination of mFold, RNAComposer, and molecular dynamics simulation could generate 14-16, 28, or 29 nucleotides length of 3D RNA aptamer with similar geometry and topology to the experimentally determined structures. The non-canonical basepair structure of the aptamer loop was formed through the MD simulation, which also improved the three-dimensional RNA aptamers model. Clustering analysis was recommended to choose the more representative model.
Exploring bacterial community composition and immune gene expression of European eel larvae (Anguilla anguilla) in relation to first-feeding diets
Authors: Bandara Kasun A. , Benini Elisa , Politis Sebastian N. , Conceição Luis E. C. , Santos André , Sørensen Sune Riis , Tomkiewicz Jonna , Vadstein Olav
Published: July 2023

European eel (Anguilla anguilla) is a commercially important species for fisheries and aquaculture in Europe and the attempt to close the lifecycle in captivity is still at pioneering stage. The first feeding stage of this species is characterized by a critical period between 20 to 24 days post hatch (dph), which is associated with mortalities, indicating the point of no return. We hypothesized that this critical period might also be associated with larvae-bacterial interactions and the larval immune status. To test this, bacterial community composition and expression of immune and stress-related genes of hatchery-produced larvae were explored from the end of endogenous feeding (9 dph) until 28 dph, in response to three experimental first-feeding diets (Diet 1, Diet 2 and Diet 3). Changes in the water bacterial community composition were also followed. Results revealed that the larval stress/repair mechanism was activated during this critical period, marked by an upregulated expression of thehsp90gene, independent of the diet fed. At the same time, a shift towards a potentially detrimental larval bacterial community was observed in all dietary groups. Here, a significant reduction in evenness of the larval bacterial community was observed, and several amplicon sequence variants belonging to potentially harmful bacterial genera were more abundant. This indicates that detrimental larvae-bacteria interactions were likely involved in the mortality observed. Beyond the critical period, the highest survival was registered for larvae fed Diet 3. Interestingly, genes encoding for pathogen recognition receptor TLR18 and complement component C1QC were upregulated in this group, potentially indicating a higher immunocompetency that facilitated a more successful handling of the harmful bacteria that dominated the bacterial community of larvae on 22 dph, ultimately leading to better survival, compared to the other two groups.
Economic geography of innovation: The effect of gender-related aspects of co-inventor networks on country and regional innovation
Authors: Tahmooresnejad Leila , Turkina Ekaterina
Published: July 2023

This paper focuses on the analysis of the effects of inventor networks on country and regional innovation. We use data from an OECD inventor database that spans more than forty years to build collaboration networks in which the network nodes are countries and regions, and linkages are patents produced by inventors from different regions and countries. We first investigate the network that includes all inventors and then analyze the network focusing on women inventors. We argue that both country and regional-level network centrality positively affect country and regional innovation (with stronger effects at the country level), and centrality in collaborations that involve women has an additional positive impact. We also find that women inventors’ share in the pool of inventors is positively associated with innovation quality both at the county and regional levels. Furthermore, our findings indicate that in the network of women inventors, countries and regions that are in cohesive clusters (formed by repeated interactions between interconnected actors) show stronger innovation performance. Our study also highlights important nuances between country-level and region-level effects.
Effect of place-based policy on regional economic growth: A quasi-natural experiment from China’s Old Revolutionary Development Program
Authors: Pan Dan , Zhou Peiyao , Kong Fanbin
Published: July 2023

Triggering economic growth is a requirement to promote human welfare and realize sustainable development in many developing countries. However, place-based policies’ impact on economic growth is debatable, and its underlying mechanism is unknown. China’s Old Revolutionary Development Program (ORDP) is a large-scale and novel type of place-based policy targeted at undeveloped regions in China. We evaluate the effect of ORDP on economic growth by employing a time-varying difference-in-differences model and further explore the potential mechanisms and heterogeneity effects. VIIRS/DNB nightlight data is used to measure economic growth. We find that ORDP can significantly promote economic growth by 4.0% and the result is still robust after several tests. Mechanism analysis shows that ORDP can improve economic growth through government intervention, industrial structure optimization, and information infrastructure construction. Heterogeneity analysis indicates that the ORDP performs better on economic growth in central Chinese cities and high-economy cities. At the same time, our paper provides three practical suggestions for stimulating economic growth in ORDP, which can be enlightening for other developing countries.
Intelligent identification of natural gas pipeline defects based on improved pollination algorithm
Authors: Gao Yiqiong , Luo Zhengshan , Wanng Yuchen , Luo Jihao , Wang Qingqing , Wang Xiaomin , Bi Aorui
Published: July 2023

As a natural gas pipeline approaches the end of its service life, the integrity of the pipeline starts failing because of corrosion or cracks. These and other defects affect the normal production and operation of the pipeline. Therefore, the identification of pipeline defects is critical to ensure the normal, safe, and efficient operation of these pipelines. In this study, a combination of adaptive adjustment based on conversion probability and Gaussian mutation strategy was used to improve the flower pollination algorithm (FPA) and enhance the search ability of traditional flower pollination. The adaptive adjustment of the transition probability effectively balances the development and exploration abilities of the algorithm. The improved flower pollination algorithm (IFPA) outperformed six classical benchmark functions that were used to verify the superiority of the improved algorithm. A Gaussian mutation strategy was integrated with IFPA to optimise the initial input weights and thresholds of the extreme learning machine (ELM), improve the balance and exploration ability of the algorithm, and increase the efficiency and accuracy for identifying pipeline defects. The proposed IFPA-ELM model for pipeline defect identification effectively overcomes the tendency of FPA to converge to local optima and that of ELM to engage in overfitting, which cause poor recognition accuracy. The identification rates of various pipeline defects by the IFPA-ELM algorithm are 97% and 96%, which are 34% and 13% higher, respectively, than those of FPA and FPA-ELM. The IFPA-ELM model may be used in the intelligent diagnosis of pipeline defects to solve practical engineering problems. Additionally, IFPA could be further optimised with respect to the time dimension, parameter settings, and general adaptation for application to complex engineering optimisation problems in various fields.
Scikick: A sidekick for workflow clarity and reproducibility during extensive data analysis
Authors: Carlucci Matthew , Bareikis Tadas , Koncevičius Karolis , Gibas Povilas , Kriščiūnas Algimantas , Petronis Art , Oh Gabriel
Published: July 2023

Reproducibility is crucial for scientific progress, yet a clear research data analysis workflow is challenging to implement and maintain. As a result, a record of computational steps performed on the data to arrive at the key research findings is often missing. We developed Scikick, a tool that eases the configuration, execution, and presentation of scientific computational analyses. Scikick allows for workflow configurations with notebooks as the units of execution, defines a standard structure for the project, automatically tracks the defined interdependencies between the data analysis steps, and implements methods to compile all research results into a cohesive final report. Utilities provided by Scikick help turn the complicated management of transparent data analysis workflows into a standardized and feasible practice. Scikick version 0.2.1 code and documentation is available as supplementary material. The Scikick software is available on GitHub (https://github.com/matthewcarlucci/scikick) and is distributed with PyPi (https://pypi.org/project/scikick/) under a GPL-3 license.
Evaluation of an inducible knockout system in insect cells based on co-infection and CRISPR/Cas9
Authors: Hausjell Christina Sophie , Klausberger Miriam , Ernst Wolfgang , Grabherr Reingard
Published: July 2023

Due to comparably high product titers and low production costs, the baculovirus/insect cell expression system is considered a versatile production platform in the biopharmaceutical industry. Its excellence in producing complex multimeric protein assemblies, including virus-like particles (VLPs), which are considered promising vaccine candidates to counter emerging viral threats, made the system even more attractive. However, the co-formation of budded baculovirus during VLP production poses a severe challenge to downstream processing. In order to reduce the amount of budded baculovirus in the expression supernatant we developed an inducible knockout system based on CRISPR/Cas9 and co-infection with two baculoviral vectors: one bringing along the Cas9 nuclease and the other one having incorporated the sequence for sgRNA expression. With our set-up high titer viruses can be generated separately, as only when both viruses infect cells simultaneously a knockout can occur. When budding essential genes gp64 and vp80 were targeted for knockout, we measured a reduction in baculovirus titer by over 90%. However, as a consequence, we also determined lower overall eYFP fluorescence intensity showing reduced recombinant protein production, indicating that further improvements in engineering as well as purification are required in order to ultimately minimize costs and timeframes for vaccine production utilizing the baculovirus/insect cell expression system.