bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherent effects of photodissociation of molecules
Authors: Metiu H.
Published: February 2023

(Summary not available.)
Novel optoelectronic scheme for subpicosecond laser-timing stabilization
Authors: Pan Ci-Ling , Chang C. T. , Wu H. H.
Published: February 2023

Timing synchronization of optical with electrical signals has been realized recently by using a photoconductive switch in a phase-lock loop (PLL) as an optoelectronic timing discriminator (OETD) or phase detector.1 In this work, we present results on stabilization of the timing fluctuations of a pulse-compressed cw actively mode-locked Nd:Yag laser (82MHz system) by using this technique. Two photoconductive switches were optically activated and operated at the quiescent points of the inverse slopes of the biasing electrical pulse from a comb generator. The difference in the output of the two switches serves as the OETD output. The comb was driven at 246 MHz by a frequency synthesizer serving as the frequency reference. The signal driving the mode-locker was generated by frequency division (by 6) from the reference oscillator such that the laser pulse timing jitter could be suppressed by using a voltage-controlled phase shifter driven by the amplified and filtered output of the OETD. 1. Ci-Ling Pan and H.-H. Wu, IEEE Photon. Technol. Lett, vol. 4, 1300 (1992).
Embedded subwavelength grating structures: design principles and applications
Authors: Norton Scott M. , Morris G. Michael
Published: February 2023

Embedded sub-wavelength grating structures provide an alternative to present narrowband filter, polarization and laser-mode selector options. By filling in the grooves of a dielectric surface-relief grating with a high index material, the grating region can be made to support leaky modes. Coupling to these leaky modes can occur if an incident field has the proper wavelength, polarization, and angle; this results in resonance effects which are characterized by extreme narrowband, sharp peaks in reflectivity and transmissivity over wavelength and angle. In this paper, general design principles for sub-wavelength grating structures are discussed. We present results based on rigorous diffraction theory that describe the effects of period, duty cycle, thicknesses, refractive indices, and polarization on the location and linewidth of resonant excitation. We have developed designs with band-pass linewidths on the order of Δλ/λ ~ 10−7, where the peak center wavelength can be shifted by Δλ/λ ≈ 0.2 for angular detunings of Δθ 75°. In addition, with more exotic structures it may be possible to do electrical tuning as well. These results are consistent with principles based on waveguide-coupling concepts. Narrowband filters can be fabricated using current lithographic techniques and together with sputtering and/or chemical deposition.
Computational models for the topological selectivity in early and primitive vision systems
Authors: Barth Erhardt , Ferraro Mario , Zetzsche Christoph , Rentschler Ingo
Published: February 2023

A rich body of work in the cognitive sciences shows that humans are able to perceive topological properties at a basic level (short time presentation, apparent motion). Minsky and Papert proved that the perceptron cannot compute topological primitives like connectedness. This has been used as an argument against computational approaches to early vision (L. Chen, 1982, Science, 218, 699-700). A recent finding by Lettvin (personal communication, 1991) provides a further challenge to computer vision scientists. Lettvin found that the “bug detector” does not respond to 3 dark blobs, unless they are connected with 2 lines.
Interactions across spatial scales and the size-disparity correlation in stereopsis
Authors: Smallman Harvey S. , MacLeod Donald I.A.
Published: February 2023

We recently presented evidence for a strong correlation between spatial frequency and the range of disparities processed (the so-called “size-disparity correlation”) in stereopsis at contrast threshold in narrowband filtered random-dot stereograms. A determination of stereothreshold with standing disparity with these targets also demonstrates this correlation. Stereothresholds increased away from the fixation plane faster for stimuli of high- than of low center spatial frequency. Stereothresholds could be measured over a greater range of standing disparities with low- than with high frequency targets.
Numerical simulation methods for complex semiconductor-laser geometries*
Authors: Hadley G. Ronald
Published: February 2023

Numerical simulation has become an essential tool in the study and design of semi-conductor lasers, partly owing to the high cost of fabrication of these devices. Recent increases in device complexity combined with the availability of ever faster computers have resulted in the employment of a rich variety of simulation methods for describing both the transport of carriers and heat, and the competition between optical modes inside the laser cavity. The resulting predictive capability has played a significant role in the design of new diode lasers emitting higher optical powers with better beam quality. In this talk I will concentrate on that feature most unique to diode laser simulation - the optical cavity model. This component of the overall simulation is responsible for the prediction of modal near- and far-field patterns, cavity losses, and the relative gains of the dominant modes. The latter quantities depend primarily on the transverse shapes of the modes. If these are determined solely by a device structure that is constant along the cavity length, then the modal shapes may be conveniently calculated using an eigenfunction analysis. If, however, (as is often the case) the device structure varies along the cavity length, or the modal shapes are influenced strongly by the properties of the gain region, then an adaptive method such as beam propagation must be employed. I intend to explore in some depth the use of both of these methods for the modeling of laser emission from semiconductor ring lasers, edge-emitting arrays and vertical cavity arrays.
Physics of short-pulse laser ablation of water-containing tissues
Authors: Oraevsky Alexander A. , Tittel Frank K. , Jacques Steven L.
Published: February 2023

Short-pulse laser ablation of soft biological tissues has a number of advantages as compared with long pulse (CW) regime that include: minor thermal damage to layers adjacent to the irradiated volume, higher efficiency and spectral selectivity. Mechanism of ablation upon confined stress conditions was determined. It is essential for realization of full potential precision of pulsed laser ablation applied in medical treatments. The following questions were answered: (1) ablation process is not driven by photodissociation of biopolymers, why ablation occurs at temperatures below 100 °C, (2) the major fraction of absorbed laser energy undergoes tissue heating, why energy' densely required for tissue removal is ten times less as compared with enthalpy of vaporization, (3) why the crater depth per pulse can never reach the penetration depth of light. The thermomechanical model of pulsed ablation is developed. Ablation of water containing media is found to include the following stages: instant heating of irradiated volume, sharp increase of pressure, formation of negative stress transient, cavitation by tensile wave, intense ejection of an irradiated substance by growing cavitation bubbles, collapse of cavitation bubbles with formation of a shock wave, spallation of tissue by this shock wave. Important role of tissue optical heterogeneity is revealed and studied.
Computer simulation of soliton propagation and switching
Authors: Huang W. P. , Xu C. L. , Myslinski P. , Pan X. , Chrostowski J.
Published: February 2023

Computer simulation of propagation and switching of both temporal and spatial solitons is presented. The simulation is based on the solutions of a general wave equation by a newly developed beam propagation method.
High-resolution optical double resonance in laser-cooled cesium
Authors: Marquardt J.H. , Robinson H.G. , Fox R.W. , Hollberg L.
Published: February 2023

Laser cooled and trapped cesium atoms are studied by absorption spectroscopy in cascade two-photon transitions.
Confocal microscopy
Authors: Dixon A. E.
Published: February 2023

I describe the principles of confocal microscopy, including scanning stage, scanning beam, and Nipkow disk microscopes.
Optoelectronic multislotted interconnection networks
Authors: Kiamilev Fouad , Graham Christopher , Abiprojo Priotomo
Published: February 2023

Multistage interconnection Networks (MINs) are used in applications ranging from ATM switches to networks for interconnecting processors in a parallel computer.
Optical interconnection using a photo-refractive crystal with a low-power visible-light tunable laser-diode array
Authors: Yu Francis T. S. , Wen Meiyuan
Published: February 2023

An optical interconnection architecture using a photo-refractive (PR) crystal with low power visible light tunable laser diode array is proposed.
High-efficiency electro-optic grating for optical switching
Authors: Talbot Pierre J. , Maurice Joanne , Wang Song Q.
Published: February 2023

High diffraction efficiency phase-only grating is a very useful optical element widely used in many areas including spectroscopy, optical information processing, and optical interconnections.
The new blue horizon: quantum-well lasers from II-VI semiconductors
Authors: Nurmikko Arto , Gunshor Robert
Published: February 2023

The combination of effective quantum well and superlattice structures, coupled with seminal advances in doping, have led to many demonstrations of diode laser operation at blue/green wavelengths in the past two years.
High-density near-field optical recording
Authors: Betzig E.
Published: February 2023

Near-field scanning optical microscopy (NSOM) has been used to record and image domains in thin-film magneto-optic materials.
Controlled, periodic domain reversal in strontium barium niobate induced by volume holograms
Authors: Kewitsch A. , Segev M. , Yariv A. , Neurgaonkar R.
Published: February 2023

Typical photorefractive space charge fields accumulated during the writing of volume holograms are of the order of the coercive field in strontium barium niobate (kV/ cm).
Angle- and spatially-multiplexed holographic memory using a 90° geometry
Authors: Burr Geoffrey W. , Mok Fai H. , Psaltis Demetri
Published: February 2023

We present experimental results of a volume holographic memory using a 90° geometry—reference and signal at right angles.
Phase-diversity wave-front sensor for imaging systems: experimental results
Authors: Kendrick Richard L. , Acton D. S. , Duncan A. L.
Published: February 2023

A phase diversity wavefront sensor has been developed and tested at the Lockheed Palo Alto Research Labs (LPARL).
Single-mode image transmission by means of wavelength-division multiplexing: theoretical study of system performance
Authors: Yu Francis T. S. , Yang X. , Uang C. M. , Lu G. W. , Zhang J. Z.
Published: February 2023

A novel approach to transmit 2-D image data through a single-model fiber via wavelength-division-multiplexing (WDM) technique is proposed.
Mappings between color spaces
Authors: MacLeod Donald I. A.
Published: February 2023

Acknowledged inaccuracies of the standard CIE 1931 colorimetric system limit the usefulness of colorimetric data for characterizing the visual effects of non-spectral light stimuli.
Ultrastable laser-diode-pumped Nd:YAG lasers
Authors: Nakagawa K. , Katsuta T. , Shelkovnikov A.S. , Ohtsu M.
Published: February 2023

We report the performance of the frequency stabilized LD pumped Nd:YAG lasers. We have obtained the frequency noise level of about 3×10−4 Hz/Hz in the error signal and the beat-note line-width of about 100 Hz between two stabilized lasers.
Design of a novel, multimode input polymeric star coupler for multiwavelength optical networks
Authors: Ilic Igor , Scarmozzino Robert , Osgood Richard M. , Yardley James T. , Beeson Karl W. , McFarland. Michael J.
Published: February 2023

Current multiwave-length optical network designs are based on the application of passive N×N star couplers.
Error performance of electroabsorptive multiple-quantum-well modulators
Authors: Zhao Yang , Feng Zhengzhong , Wu Cunkai
Published: February 2023

The error performance for electroabsorptive multiple quantum well (MQW) modulators is limited by the on/off ratio and insertion loss of the devices.
Self-trapped solutions on fiber arrays: analytical results
Authors: Aceves Alejandro B. , De Angelis Costantino C.
Published: February 2023

Fiber arrays, which consists of N fibers coupled through evanescent fiber overlap and disposed in one or two dimensional geometries, are currently the subject of theoretical and practical investigations, because it is an optimum candidate to be used in all-optical signal processing.
Virtual-point-source multipass laser-diode pumping of optically thin rods
Authors: Ueda Ken-ichi , Wazumi Koichiro
Published: February 2023

For the gravitational wave detection,1 we have to stabilize high power lasers of 1 kW output to their shot noise limits. Nobody have such high power and single mode stabilized lasers.
Optical parallel genetic algorithms to train fuzzy neural networks for control applications
Authors: Osei Albert , Caulfield John , Shamir Joseph
Published: February 2023

Our goal is to design and implement an optical selectionist system. The main idea is that an optical system can implement fuzzy neural networks.
Photoselection and the control of molecular photoionization
Authors: Bryant Gregg , Shehadeh Rana , Yin Yi-Yian , Jiang Yanan , Elliott Daniel , Grant Edward
Published: February 2023

As a universal form of photofragmentation, photoionization constitutes an ideal form of chemical change by which to demonstrate radiative control.
Molecular photoionization dynamics obtained by using coherent VUV radiation
Authors: White Michael G , Wiedmann Ralph T.
Published: February 2023

Threshold photoelectron spectroscopy based on pulsed field ionization (PFI) has been used in conjunction with a VUV laser source to obtain the rovibronic distributions of molecular cations following single photon ionization.
Group-velocity description of Gaussian pulse propagation of arbitrary initial pulse width
Authors: Balictsis Constantinos M. , Oughstun Kurt E.
Published: February 2023

The modified asymptotic description of Gaussian pulse propagation in a linear, causally dispersive dielectric asserts, in accordance with classical asymptotic methods of analysis, that as the rise-time of the input Gaussian envelope is decreased below the medium relaxation time the propagated field separates into two distinct pulses due to the appearance of electromagnetic transients that are characteristic of the dispersive medium.
Electromagnetic-energy dissipation of plane-wave pulses in a causal, dispersive dielectric
Authors: Smith Paul D. , Oughstun Kurt E.
Published: February 2023

The dissipation of electromagnetic energy from a plane-wave pulse which is propagating in a Lorentz medium is investigated.
Near-field diffraction of scalar optical fields
Authors: Kowarz Marek W.
Published: February 2023

Important applications such as near-field microscopy and high-density optical data storage have recently prompted considerable interest in near-field optics, where both the propagation distances and the spatial features are smaller than a wavelength.
Monolithic GaAs p-i-n/MESFET photoreceiver
Authors: Nichols D. T. , Dutta N. K. , Berger P. R. , Smith P. R. , Sivco D. L. , Cho A. Y.
Published: February 2023

Optoelectronic integrated circuits (OEICs) are important for the next generation optical data transmission and switching systems. Among the important OEIC technologies are the photoreceiver and phototransmitter fabrication technology.
Approaching ultimate limitations in ultrashort-optical-pulse generation
Authors: Krausz F. , Brabec T. , Curley P. , Spielmann Ch. , Wintner E. , Schmidt A. J.
Published: February 2023

Tremendous progress has recently been made in the development of femtosecond solid state laser systems.
Aperture-limited confocal resonator: a resonator design providing large Gaussian beam radii
Authors: Hodgson Norman , Ozygus Bernd , Schabert Frank , Weber Horst
Published: February 2023

The confocal resonator consists of two equally curved mirrors which are separated by the curvature ρ.
Faster learning with a smart neuron for linearly inseparable problems
Authors: Ahmed Farid , Awwal Abdul A. S.
Published: February 2023

In most of the neural network learning algorithms, the evolution of the network takes place after an exhaustive sequence of error minimization in multi-dimensional connection-weight space.
Fabrication of photorefractive 3-D wave-guides for optical dynamic interconnections
Authors: Itoh Kazuyoshi , Matoba Osamu , Ichioka Yoshiki
Published: February 2023

Optical interconnection is believed to be a key technology to parallel distributed computing systems.
Multichannel fingerprint identification by means of four-wave mixing in a photorefractive crystal
Authors: Zhou Shaomin , Yeh Pochi , Liu Hua-Kuang
Published: February 2023

A multichannel optical fingerprint pattern association and recognition system is proposed and demonstrated with high processing speed and larger information capacity.
Optical filtering in magneto-optic storage devices
Authors: Milster T. D. , Li W. , Wang M. S.
Published: February 2023

Optical storage devices are basically scanning optical microscopes. A focused laser beam illuminates one recorded track of an optical disk.
Observer performance on images produced by the linear Landweber algorithm
Authors: Abbey Craig K. , Barrett Harrison H. , Krupinski Elizabeth
Published: February 2023

The Landweber algorithm is an iterative image processing algorithm widely used in medical imaging and other applications.
Embodiment models of visual cognition
Authors: Ballard Dana H. , Hayhoe Mary M.
Published: February 2023

One of the most fundamental features of human cognitive function is that limited nature of the attentional and short-term memory resources that can be brought to bear on the performance of a task.
Scattering of phase-conjugated light by a stationary particle
Authors: Oh Choonghoon , Andrews Kelly T. , Fry Edward S. , Dunning G. J. , Minden M. L. , Pepper D. M.
Published: February 2023

It is well known that phase-conjugated light has an ability to correct the phase distortion introduced while passing through a phase distorting medium.
Spatial evolution of four-wave mixing processes in an optical fiber
Authors: Hart Darlene L. , Beletic James W. , Roy Rajarshi
Published: February 2023

The energy exchange via four-wave mixing processes between two pump waves and multiple sidebands in a single mode optical fiber are investigated.
Analysis of a GaAs/AlGaAs waveguide optical switch that has an adjustable Y-junction
Authors: Chinni V. R. , Huang T. C. , Wai P. K. A. , Menyuk C. R.
Published: February 2023

A GaAs/ AlGaAs optical switch with a Yjunction structure in which the output arms can be individually turned on or off electronically is demonstrated.1
Recent advances in femtosecond Cr4+-doped forsterite lasers
Authors: Alfano R. R. , Seas A. , Petričević V.
Published: February 2023

Performance of chromium-doped forsterite (Cr:Mg2SiO4), the first solid-state laser based on tetravalent chromium (Cr4+) as a lasing ion is reviewed.
Correlation of refractive-index profiles and substitutional hydrogen concentrations in annealed, proton-exchanged LiNbO3
Authors: Zavada J. M. , Casey H. C. , Chen Chang-Ho , States R. J. , Loni A. , Novak S. W.
Published: February 2023

Extraordinary refractive-index profiles for a set of annealed proton-exchanged z-cut LiNbO3 wafers were determined, based on optical prism-coupling measurements, and fitted with a single Gaussian diffusion expression.
Recent advances in fiber lasers
Authors: Grubb S. G.
Published: February 2023

(Summary not available.)
Diffractive optics for commercial mid- and long-wave full-field-of-view radiometers
Authors: Aldrich Robert E.
Published: February 2023

A three element all germanium 4x telescope was designed for the IQ812 industrial radiometer.
Reflective interconnection system using computer-generated gratings
Authors: Kuznia C. B. , Sawchuk A. A.
Published: February 2023

Each pixel of a smart pixel array contains one or more optical I/O devices (lasers, modulators and detectors) integrated with electronic processing.
Laser versus blackbody photostochastic fluctuations
Authors: Steely S. L.
Published: February 2023

Lasers are used for beam and signal modulation during infrared photodetector evaluation.
Spatial-frequency channels process text
Authors: Solomon J. A. , Pelli D. G.
Published: February 2023

We measured contrast thresholds in high- and low-pass noise for identifying letters and detecting gratings. Assuming that squared contrast threshold is proportional to the total noise power passed by a single linear filter (“channel”), we calculated modulation transfer functions for the visual filters underlying the performance of each task. The filters used for letter identification and grating detection are remarkably similar.
High-efficiency single-longitudinal-mode laser
Authors: Zhou Shouhuan
Published: February 2023

This is a new type laser composed by two resonators. It conquers the contradiction between the efficiency and the quality of single longitudinal mode (SLM), and there is no strict matching requirement for resonator and modes of injection locking.
Intrinsic instabilities of cooperative upconversion dynamics in lasers
Authors: Rand S. C. , Xie P.
Published: February 2023

When the 2.8 µm erbium laser is pumped well above threshold an instability is observed at a unique pumping wavelength which causes the laser inversion to be produced by interactions among neighboring impurity ions. We show experimentally that this instability does not occur at equivalent levels over threshold when excitation is provided at wavelengths other than 1.5 µm. This behavior is compared with the results of two theoretical approaches to a description of the nonlinear dynamics, namely a rate equation and a density matrix solution. It is shown theoretically that instabilities may originate from two different physical mechanisms in pair-pumped laser systems, both of which are related to the nonlinear upconversion terms. Oscillatory solutions for the laser output may arise either from interplay of the nonlinear upconversion response with cavity photon density or from delocalization of the pair interaction. Details of these predictions are compared with time series of the laser output to shed light on the true origin of the observed instabilities. A possible explanation of excess amplitude noise in conventional infrared Erbium lasers is offered.
Noise propagation in iterative nonlinear algorithms
Authors: Barrett Harrison H. , Wilson Donald W. , Tsui Benjamin M. W.
Published: February 2023

The expectation-maximization (EM) algorithm is a nonlinear iterative algorithm that attempts to find the ML estimate of the object that produced a data set. The convergence of the algorithm and other deterministic properties are well established, but relatively little is known about how noise in the data influences noise in the final processed image. In this paper we present a detailed treatment of these statistical properties. The specific application we choose for this study is image reconstruction in emission tomography, but the results are valid for any application of the EM algorithm in which the data set can be described by Poisson statistics. We show that the probability density function for the gray level at a pixel in the reconstructed image is well approximated by a log-normal law. An expression is derived for the mean and variance of the gray level and for pixel-to-pixel covariance. All of these quantities vary with iteration number and with the original object distribution in a manner predicted by the theory. We also report an extensive Monte Carlo study that validates the theory over a wide range of experimental conditions.
Graphene quantum dot bolometer camera: practical approaches and preliminary results
Authors: Fatimy abdelouahad El , Martyniuk Oleh , chaudhary vivek , Bartos Miroslav , Laguta Oleksii , Myers-Ward Rachael L. , Gaskill Kurt , barbara paola , Neugebauer Petr
Published: February 2023

Graphene is an exciting candidate for the detection of high-frequency electromagnetic radiation. Here, we have studied the bolometric performance of epitaxial graphene quantum dots (Q.D.s) on the silicon carbide (SiC) substrate in the terahertz (THz) range. The graphene Q.D. having a diameter in the 200 nm range, exhibited an extremely high resistance variation with temperature up to 4.7 MΩ K-1, a crucial parameter for the hot electron bolometers. The graphene Q.D.s bolometers have been fabricated in different geometrical configurations, such as variations in electrode spacing (2.5 and 5.0 μm) and parallelly connected arrays of 4 and 8 Q.D.s. It is demonstrated that the absorbed power can be improved by tuning the bolometer geometrical configuration and the active graphene area, and the electrical responsivity is still very high for an extensive range of absorbed power. Additionally, we report that the photo response of graphene Q.D. bolometer devices is meagerly affected by the presence of a magnetic field as high as 15 T. The results presented here open ways to continue to optimize and realize the chip-scale matrix of the graphene Q.D.s bolometers for THz imaging and magneto-optical spectroscopy applications.
A novel binary pesticidal protein from Chryseobacterium arthrosphaerae controls western corn rootworm by a different mode of action to existing commercial pesticidal proteins
Authors: Jabeur Rania , Guyon Virginie , Toth Szabolcs , Pereira Adriano E. , Huynh Man P. , Selmani Zakia , Boland Erin , Bosio Mickael , Beuf Laurent , Clark Pete , Vallenet David , Achouak Wafa , Audiffrin Carine , Torney François , Paul Wyatt , Heulin Thierry , Hibbard Bruce E. , Toepfer Stefan , Sallaud Christophe
Published: February 2023

The western corn rootworm (WCR)Diabrotica virgifera virgifera(Coleoptera: Chrysomelidae) remains one of the economically most important pests of maize (Zea mays) due to its adaptive capabilities to pest management options. This includes the ability to develop resistance to some of the commercial pesticidal proteins originating from different strains ofBacillus thuringiensis. Although urgently needed, the discovery of new, environmentally safe agents with new modes of action is a challenge. In this study we report the discovery of a new family of binary pesticidal proteins isolated from severalChryseobacteriumspecies. These novel binary proteins, referred to as GDI0005A and GDI0006A, produced as recombinant proteins, prevent growth and increase mortality of WCR larvae, as does the bacteria. These effects were found both in susceptible and resistant WCR colonies to Cry3Bb1 and Cry34Ab1/Cry35Ab1 (reassigned Gpp34Ab1/Tpp35Ab1). This suggests GDI0005A and GDI0006A may not share the same binding sites as those commercially deployed proteins and thereby possess a new mode of action. This paves the way towards the development of novel biological or biotechnological management solutions urgently needed against rootworms.
An optimized electrotransformation protocol for Lactobacillus jensenii
Authors: Fristot Elsa , Bessede Thomas , Camacho Rufino Miguel , Mayonove Pauline , Chang Hung-Ju , Zuniga Ana , Michon Anne-Laure , Godreuil Sylvain , Bonnet Jérôme , Cambray Guillaume
Published: February 2023

Engineered bacteria are promising candidates for in situ detection and treatment of diseases. The female uro-genital tract presents several pathologies, such as sexually transmitted diseases or genital cancer, that could benefit from such technology. While bacteria from the gut microbiome are increasingly engineered, the use of chassis isolated from the female uro-genital resident flora has been limited. A major hurdle to implement the experimental throughput required for efficient engineering in these non-model bacteria is their low transformability. Here we report an optimized electrotransformation protocol for Lactobacillus jensenii, one the most widespread species across vaginal microflora. Starting from classical conditions, we optimized buffers, electric field parameters, cuvette type and DNA quantity to achieve an 80-fold improvement in transformation efficiency, with up to 3.5·103 CFUs/μg of DNA in L. jensenii ATCC 25258. We also identify several plasmids that are maintained and support reporter gene expression in L. jensenii. Finally, we demonstrate that our protocol provides increased transformability in three independent clinical isolates of L. jensenii. This work will facilitate the genetic engineering of L. jensenii and enable its use for addressing challenges in gynecological healthcare.
TorchDIVA: An extensible computational model of speech production built on an open-source machine learning library
Authors: Kinahan Sean P. , Liss Julie M. , Berisha Visar
Published: February 2023

The DIVA model is a computational model of speech motor control that combines a simulation of the brain regions responsible for speech production with a model of the human vocal tract. The model is currently implemented in Matlab Simulink; however, this is less than ideal as most of the development in speech technology research is done in Python. This means there is a wealth of machine learning tools which are freely available in the Python ecosystem that cannot be easily integrated with DIVA. We present TorchDIVA, a full rebuild of DIVA in Python using PyTorch tensors. DIVA source code was directly translated from Matlab to Python, and built-in Simulink signal blocks were implemented from scratch. After implementation, the accuracy of each module was evaluated via systematic block-by-block validation. The TorchDIVA model is shown to produce outputs that closely match those of the original DIVA model, with a negligible difference between the two.

We additionally present an example of the extensibility of TorchDIVA as a research platform. Speech quality enhancement in TorchDIVA is achieved through an integration with an existing PyTorch generative vocoder called DiffWave. A modified DiffWave mel-spectrum upsampler was trained on human speech waveforms and conditioned on the TorchDIVA speech production. The results indicate improved speech quality metrics in the DiffWave-enhanced output as compared to the baseline. This enhancement would have been difficult or impossible to accomplish in the original Matlab implementation. This proof-of-concept demonstrates the value TorchDIVA can bring to the research community. Researchers can download the new implementation at: https://github.com/skinahan/DIVA_PyTorch.
Grain size and shape fractal characteristics of gangue in the process of ’jaw breaking-ball milling’
Authors: Gu Wenzhe , Zhu Lei , Liu Zhicheng , He Zhiwei
Published: February 2023

This study investigates the fractal characteristics of the particle size and shape distribution of gangue powder in the "jaw crushing-ball milling" process using mudstone gangue. For this, fractal theory, laser particle size analyzer, scanning electron microscope and other mesoscopic research methods were introduced. This study has several main factors, including the discharge port width in the jaw crushing stage, the grinding particle size, ball-to-powder ratio in the ball milling stage, and the fractal dimension changes of the gangue in different crushing stages. The results indicate that in the process of "jaw crushing-ball milling", gangue’s particle size and shape fractal dimension values changed periodically. During the jaw crushing stage, the particle size fractal dimension increases with the width of the discharge opening, ranging from 1.85 to 1.92. The value of the shape fractal dimension varies from 2.65 to 2.84. Ball milling causes the fractal dimension value of gangue particle size to increase with time before agglomeration and decrease after agglomeration. By comparing different in-grinding particle sizes and ball-to-powder ratio, it is found that the fractal dimension value of gangue particle size decreases with the increase of in-grinding particle size and increases with the increase of ball-to-powder ratio. The final gangue’s particle size fractal dimension value is concentrated between 2.5 and 2.8. The fractal dimension of particle shape increases with the increase of the grinding particle size, and decreases with the increase of ball-to-powder ratio. A ball-to-powder ratio greater than 6 gradually reduces its influence on fractal dimensions, and the final shape dimension lies between 1.06 and 1.16. In addition, the increase/decrease range of particle size and shape fractal dimension decreases with the increase of ball milling time, which is also consistent with the grinding kinetics theory. As a result of the changes in particle size and shape fractal dimensions, parameters such as jaw crusher discharge port width, grinding particle size, and ball-to-powder ratio are calculated to provide a theoretical basis for the entire crushing process in the "jaw crusher-ball milling" crushing process.
Prevalence and incidence of hypertension in a heavily treatment-experienced cohort of people living with HIV in Uganda
Authors: Byonanebye Dathan M. , Polizzotto Mark N. , Parkes-Ratanshi Rosalind , Musaazi Joseph , Petoumenos Kathy , Castelnuovo Barbara
Published: February 2023

Introduction

The effect of long-term exposure to antiretroviral therapy (ART) on hypertension in sub-Saharan Africa remains unclear. We aimed to determine the prevalence and incidence of hypertension in people living with HIV (PLWH) with more than 10 years of ART in Uganda.

Methods

The analysis was performed within a cohort of adult PLWH with more than 10 years of ART at an HIV clinic in Kampala, Uganda. Participants were eligible for this analysis if they had ≥2 follow-up visits. Hypertension was defined as two consecutive systolic blood pressure (SBP) measures greater than 140 mmHg and/or diastolic blood pressure (DBP) greater than 90 mmHg, and/or documented diagnosis and/or the initiation of antihypertensives. We determined the proportion of PLWH with hypertension at baseline and used multivariable logistic regression to determine the factors associated with prevalent hypertension. To determine the incidence of hypertension, follow-up began from the cohort baseline date and was censored at the last clinic visit or date of the event, whichever occurred earlier. Multivariable Poisson regression was used to determine the adjusted incidence rate ratios (aIRR) of hypertension according to demographic, ART, and clinical characteristics.

Results

Of the 1000 ALT participants, 970 (97%) had ≥2 follow-up visits, and 237 (24.4%) had hypertension at baseline. The odds of prevalent hypertension were 1.18 for every 5-year increase in age (adjusted odds ratio (aOR) 1.18, 95% CI 1.10–1.34) and were higher among males (aOR 1.70, 95% CI 1.20–2.34), participants with diabetes mellitus (aOR 2.37, 95% CI 1.10–4.01), obesity (aOR 1.99, 95% CI 1.08–3.60), high cholesterol (aOR 1.47, 95% CI 1.16–2.01), and those with prior exposure to stavudine (aOR 2.10, 95% CI 1.35–3.52), or nevirapine (aOR 1.90, 95% CI 1.25–3.01). Of the 733 participants without hypertension at baseline, 116 (15.83%) developed hypertension during 4671.3 person-years of follow-up (incidence rate 24.8 per 1000 person-years; 95% CI 20.7–29.8). The factors associated with incident hypertension were obesity (adjusted incidence rate ratio (aIRR) 1.80, 95% CI 1.40–2.81), older age (aIRR 1.12 per 5-year increase in age, 95% CI 1.10,1.25), and renal insufficiency (aIRR1.80, 95% CI 1.40–2.81).

Conclusion

The prevalence and incidence of hypertension were high in this heavily treated PLWH cohort. Therefore, with increasing ART coverage, HIV programs in SSA should strengthen the screening for hypertension in heavily treated PLWH.
Rapid generation of homogenous tumor spheroid microtissues in a scaffold-free platform for high-throughput screening of a novel combination nanomedicine
Authors: Abolhassani Hossein , Zaer Mohammad , Shojaosadati Seyed Abbas , Hashemi-Najafabadi Sameereh
Published: February 2023

Combination nanomedicine is a potent strategy for cancer treatment. Exploiting different mechanisms of action, a novel triple drug delivery system of 5-fluorouracil, curcumin, and piperine co-loaded human serum albumin nanoparticles (5FU-CUR-PIP-HSA-NPs) was developed via the self‐assembly method for suppressing breast tumor. Both hydrophobic and hydrophilic drugs were successfully encapsulated in the HSA NPs with a high drug loading efficiency (DLE) of 10%. Successful clinical translation of nanomedicines, however, is a challenging process requiring considerable preclinical in vitro and in vivo animal tests. The aim of this study was to develop a homemade preclinical 3D culture model in the standard 96-well plates in a cost and time-effective novel approach for the rapid generation of homogenous compact tumor spheroids for disease modeling, and anticancer therapeutic/nanomedicine screening. The knowledge of drug screening can be enhanced by employing such a model in a high-throughput manner. Accordingly, to validate the formulated drug delivery system and investigate the cellular uptake and cytotoxicity effect of the nanoformulation, 3D tumor spheroids were employed. The practicality of the nanomedicine system was substantiated in different tests. The in vitro uptake of the NPs into the tight 3D tumor spheroids was facilitated by the semi-spherical shape of the NPs with a proper size and surface charge. 5FU-CUR-PIP-HSA-NPs demonstrated high potency of migration inhibition as a part of successful anti-metastatic therapy as well. The remarkable differences in 2D and 3D cytotoxicities emphasize the importance of employing 3D tumor models as an intermediate step prior to in vivo animal experiments for drug/nanomedicine screening.
Tripartite interactions between filamentous Pf4 bacteriophage, Pseudomonas aeruginosa, and bacterivorous nematodes
Authors: Schwartzkopf Caleb M. , Robinson Autumn J. , Ellenbecker Mary , Faith Dominick R. , Schmidt Amelia K. , Brooks Diane M. , Lewerke Lincoln , Voronina Ekaterina , Dandekar Ajai A. , Secor Patrick R.
Published: February 2023

The opportunistic pathogen Pseudomonas aeruginosa PAO1 is infected by the filamentous bacteriophage Pf4. Pf4 virions promote biofilm formation, protect bacteria from antibiotics, and modulate animal immune responses in ways that promote infection. Furthermore, strains cured of their Pf4 infection (ΔPf4) are less virulent in animal models of infection. Consistently, we find that strain ΔPf4 is less virulent in a Caenorhabditis elegans nematode infection model. However, our data indicate that PQS quorum sensing is activated and production of the pigment pyocyanin, a potent virulence factor, is enhanced in strain ΔPf4. The reduced virulence of ΔPf4 despite high levels of pyocyanin production may be explained by our finding that C. elegans mutants unable to sense bacterial pigments through the aryl hydrocarbon receptor are more susceptible to ΔPf4 infection compared to wild-type C. elegans. Collectively, our data support a model where suppression of quorum-regulated virulence factors by Pf4 allows P. aeruginosa to evade detection by innate host immune responses.
Transcriptionally active nasopharyngeal commensals and opportunistic microbial dynamics define mild symptoms in the COVID 19 vaccination breakthroughs
Authors: Devi Priti , Kumari Pallawi , Yadav Aanchal , Tarai Bansidhar , Budhiraja Sandeep , Shamim Uzma , Pandey Rajesh
Published: February 2023

The development of COVID 19 vaccines as an effort to mitigate the outbreak, has saved millions of lives globally. However, vaccination breakthroughs have continuously challenged the vaccines’ effectiveness and provided incentives to explore facets holding potential to alter vaccination-induced immunity and protection from subsequent infection, especially VOCs (Variants Of Concern). We explored the functional dynamics of nasopharyngeal transcriptionally active microbes (TAMs) between vaccination breakthroughs and unvaccinated SARS-CoV-2 infected individuals. Microbial taxonomic communities were differentially altered with skewed enrichment of bacterial class/genera of Firmicutes and Gammaproteobacteria with grossly reduced phylum Bacteroidetes in vaccination breakthrough individuals. The Bacillus genus was abundant in Firmicutes in vaccination breakthrough whereas Prevotella among Bacteroides dominated the unvaccinated. Also, Pseudomonas and Salmonella of Gammaproteobacteria were overrepresented in vaccination breakthrough, whilst unvaccinated showed presence of several genera, Achromobacter, Bordetella, Burkholderia, Neisseria, Hemophilus, Salmonella and Pseudomonas, belonging to Proteobacteria. At species level, the microbiota of vaccination breakthrough exhibited relatively higher abundance of unique commensals, in comparison to potential opportunistic microbes enrichment in unvaccinated patients’ microbiota. Functional metabolic pathways like amino acid biosynthesis, sulphate assimilation, fatty acid and beta oxidation, associated with generation of SCFAs (short chain fatty acids), were enriched in vaccination breakthroughs. Majorly, metabolic pathways of LCFAs biosynthesis (long chain fatty acids; oleate, dodecenoate, palmitoleate, gondoate) were found associated with the unvaccinated. Our research highlights that vaccination decreases the microbial diversity in terms of depleting opportunistic pathogens and increasing the preponderance of commensals with respect to unvaccinated patients. Metabolic pathway analysis substantiates the shift in diversity to functionally modulate immune response generation, which may be related to mild clinical manifestations and faster recovery times during vaccination breakthroughs.
Gender equity in Lebanon’s news industry: The chasm between management’s perspectives and women journalists’ experience
Authors: Melki Jad
Published: February 2023

Senior management’s lack of knowledge and acknowledgement of gender injustice in journalism organizations has negative implications for the advancement of women journalists’ right to a hostile-free and equitable workplace. This study examines news leadership’s perceptions of gender inequity in the Lebanese news industry. The qualitative study relied on a focus group with sixteen senior Lebanese news managers from major journalism institutions in the country. It found the perceptions of most news managers to be inconsistent with extant research that has documented the hostile gendered work environment in the Lebanese news industry. Many of the issues that women journalists in Lebanon face, including gender discrimination, glass ceiling effects, pay inequity and sexual harassment, were neither acknowledged nor sufficiently addressed in the policies and practices of these organizations, partly due to this lack of awareness about women’s status in the industry and society.
Technology in the classroom and music teachers’ self-efficacy
Authors: Doherty Brian
Published: February 2023

This quantitative study examined the self-efficacy of music teachers in each of the technological, pedagogical and technological knowledge domains with a particular focus on their technological self-efficacy. M-TPACK questionnaire was used as its measurement tool and was sent to members of the National Association for Music Education in the United States. Overall, 475 respondents reported high levels of self-efficacy when implementing technology in their instruction. This study also revealed that music educators were discovering technology and learning to use it mostly on their own time and outside school hours. Results further validated the factor structure of Bauer’s M-TPACK survey as it pertains to music teachers for the questions measuring individual TPACK domains.
Sketching music together: Mixed groups exploring melodic similarity and contrast using a digital tabletop
Authors: Franceschini Andrea , Laney Robin
Published: February 2023

In this article, we investigate whether and how a purposely built digital tabletop musical instrument (DTMI) can help groups of novices and casual users to explore music composition. Working together in small groups around the DTMI, our participants explored how the musical concepts of melodic similarity and contrast can convey narrative through musical structure. We build on our previous work that investigated a one-to-one learner–tutor scenario and expanded it to groups of peers. Similarly to our previous study, we adopted an exploratory and primarily qualitative approach, involving 24 participants divided into eight groups of three each, sampled from the general population via flyers and word of mouth. We structured the sessions as a series of open-ended discussions of the notions of similarity and contrast, starting from a general point of view, leading up to the task of inventing a short story and composing a melody to describe it. Although the two studies may appear superficially similar, the group element represents a fundamental difference, as we found. The combination of technology and group setting was instrumental in helping less experienced participants discuss music with more experienced participants by using a simplified yet expressive representation of music that could be used to discuss complex aspects of melody and composition.
Interface entre Ecossistemas Empreendedores e Atividade Turística: Integrando Literaturas em Prol do Desenvolvimento
Authors: Oliveira Paes de Lima Marília Cláudia , Azevedo Ana Cláudia , Emmendoerfer Magnus Luiz , Cardoso de Pinho Brandão Marilia Fátima
Published: February 2023

O objetivo do estudo foi aprofundar a compreensão da interface entre a atividade turística e o ecossistema empreendedor em prol do desenvolvimento. Trata-se de uma revisão semiestruturada da literatura (Snyder, 2019), realizada na base Web of Science que levanta a produção internacional no período de 2016-2021. Após a análise de 19 artigos trouxe-se como resultado a definição compilada dos temas abordados, gerando uma estrutura para sistematização do conteúdo, dividida em quatro frentes de pesquisa: definições de ecossistemas empreendedores, estágios de desenvolvimento, dimensões de análise e ecossistemas empreendedores e o turismo. Tais resultados ampliam a compreensão acerca da contribuição do ecossistema empreendedor para o turismo e, consequentemente, para o desenvolvimento, mediante o fomento da atividade turística, além da contribuição para a literatura, haja vista que estudos anteriores mostram que apesar da aparente complementariedade desta interface, a abordagem do ecossistema empreendedor e do turismo ainda é pouco abordada em pesquisas.
Factors Influencing Disaster Preparedness and Risk Perception for Nuclear Accidents
Authors:   Crisis and Emergency Management: Theory and Praxis, Ki Jaehong , Yoon Dong Keun
Published: February 2023

When a nuclear accident occurs, measures to protect people residing around the nuclear power plant from released radioactive substances should be implemented. In order such measures to be effectively executed, residents should successfully perform actions requested by the response organizations. This research focus on disaster preparedness and risk perception for nuclear accidents, known to influence responding actions of people under disaster, and analyzed factors associated with them by questionnaire survey and the Partial Least Squares Structural Equation Modeling. Results indicate that people having higher level of confidence in the disaster response organization and experienced education regarding nuclear emergency are likely to have higher level of preparedness. And the higher level of preparedness was associated with the lower level of risk perception on the negative impacts of the nuclear accident. Policy implications derived from such results were suggested to enhance the level of preparedness, which could be one of approaches to build foundations to efficiently respond to the nuclear accident.