bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of digital-filter theory to the design of grating filters
Authors: Town Graham E.
Published: February 2023

Inverse scattering methods may be used to design coupled mode waveguide filters with either codirectional or contradirectional coupling.1 The response of these and other spatially periodic waveguiding structures is periodic in the frequency domain, a property also exhibited by digital filters. A fundamental problem in digital filter design is to closely approximate the response of a continuous system. In most cases exact replication is impossible, unless an infinite sampling frequency is used, and large amounts of memory are available. Similar problems arise in the design of corrugated waveguide filters, and are associated with finite frequency of the spatial periodicity, and finite coupling lengths. The approximation problem becomes significant when the desired waveguide filter bandwidth is comparable to the optical carrier frequency, a situation which arises when large coupling coefficients are involved, or the coupling region is short. In such situations, significant distortion of the desired spectral response can occur unless the periodicity of the spectral response is accounted for in the design process. Suitable approximation methods from digital filter theory will be shown to improve the performance of coupled mode filters designed by inverse scattering methods.
InP avalanche and p-i-n photodetectors for optical communications
Authors: Tarof Larry
Published: February 2023

InP-based photodetectors are commonly used to receive light in fiber-optical communications systems. Two of the most common devices are the avalanche and p-i-n photodiodes. In this tutorial the design and performance of these devices are described and the suitablility for particular applications is discussed. Presently active research areas include optimized performance of InP/InGaAs avalanche and p-i-n photodiodes and development of superlattice avalanche photodiodes.
Light pipe for high-intensity laser pulses
Authors: Durfee C. G. , Milchberg H. M.
Published: February 2023

Optical guiding of intense laser pulses over a distance in excess of 20 Rayleigh lengths has recently been demonstrated1 using a two pulse technique. The first pulse prepares a shock-driven, axially extended radial electron density profile which guides a second pulse, injected after an optimum delay which increases with mass of the plasma ions. More recent results include even longer guiding distances and spectroscopy of on-axis coherent emission.
Frequency stabilization and control of laser diodes
Authors: Lee Sungman , Hillman Lloyd W.
Published: February 2023

We have demonstrated wavelength tuning of diode lasers using precise temperature control. We have then stabilized the FM noise fluctuations of these lasers by using feedback control of the injection current. With these lasers and by using the saturation spectroscopy, we have resolved the Rb-D2 hyperfine absorption lines. We are using the hyperfine lines as frequency standard for stabilizing the laser. This work includes a comprehensive study of the Zeeman effect in Rb.
New dither-free technique for phase-mirror control in optical-feedback-stabilized diode-laser systems
Authors: Schnier D. , Madej A. A.
Published: February 2023

One method of improving the poor spectral characteristics of free-running laser diodes is to use the optical self-locking to an external confocal Fabry-Perot resonator.1 Locking only occurs when the diode-cavity light path is an integral multiple of the resonant wavelength. This can be achieved by a piezo mounted mirror located between laser diode and resonator. We describe a simple, new technique for generating this phase mirror locking signal which is based on the observation that the relative intensities of higher order transverse modes excited in the confocal resonator change when the phase mirror is moved. The intensity difference between the spatial mode patterns leaving the resonator can then be used directly to generate the locking signal. The main theoretical aspects and the experimental realization of this new technique will be described. Two independent, identical systems employing a 674nm diode laser and resonator have been built and their frequency stability was measured. The laser linewidth is reduced to less than 100 kHz. The long-term stability was limited by the drift of the confocal resonators which were locked to polarization stabilized HeNe-lasers.
Numerical modeling of remote coupling and switching in resonant and antiresonant planar waveguide structures
Authors: Duguay Michel A.
Published: February 2023

Antiresonant reflecting optical waveguides (ARROW)1 support a leaky field which has been exploited for remote coupling and switching. We have modeled these devices using two methods. One method is based on modal interference where up to six modes are used to decompose the injected light beam. The other method is a geometrical approximation based on the coherent addition of rays reflecting and refracting at all the interfaces of the planar multiple-layer structure. We call this latter method RPM for ray propagation method. One geometry of particular interest is one where three light-guiding air layers are formed by the use of four 2-micron thick nitrocellulose pellicles. Mechanical motion of one of these pellicles by one micron suffices to efficiently switch light from one output port to the other. Another structure is designed in such a way so as to produce a wavelength-dependent switching ratio. This structure holds promise for wavelength division multiplexing applications in optical communications.
Influence of linear-k-term valence-subband mixing on electroabsorption in strained GaAs/AlGaAs quantum wells
Authors: Xue Deng-ping , Yevick David , Bardyszewski Witold
Published: February 2023

While valence subband mixing significantly affects the electroabsorption spectra, previous theories have ignored the contribution of the linear k terms in the Luttinger Hamiltonian.1 Here we study the effect of these terms by first solving the 4x4 effective mass equation for the two lowest valence subbands and then generating the exciton binding energies and wavefunctions. We find that the linear k terms couple hh 1 and lhA levels even at k = 0 so that the hh1 → cl 1s exciton transition is permitted for TM polarized light. The latter observation agrees qualitatively with experimental results.2 Further, since the linear k terms couple the exciton wavefunctions, the hh 1 and lh1 transition peaks do not cross. We expect that additional features of the linear k term induced subband mixing on the electroabsorption spectra of strained GaAs/AlGaAs quantum wells, particularly as regards selection rules, oscillator strength ratios and polarization dependence, will be observable at low temperatures.
Gas dynamics of excimer-laser ablation of polymers
Authors: Braren Bodil
Published: February 2023

Summary not available.
Transmission of coupled-gap solitons in non-linear periodic media
Authors: Lee Sangjae , Ho Seng-Tiong
Published: February 2023

The theoretical interests in gap solitons have grown recently due to their unusual properties. For example, it was found that gap solitons can propagate in a Nonlinear Periodic Dielectric Medium (NPDM) with a group velocity much slower than the usual medium group velocity. The existence of stationary solitons in a NPDM was first investigated by Chen and Mills.1 Later, de Sterke-Sipe and Christodoulides-Joseph showed that it is possible to propagate moving solitons in a NPDM. In this paper, we study the propagation of two pulses with orthogonal linear polarizations in a nonlinear periodic structure with χ(3) nonlinearity. Specifically we derive the coupled nonlinear Schrödinger equations and find their solitary-wave solutions in a simple case. We show that two orthogonally polarized pulses can co-propagate as a coupled gap soliton through a nonlinear periodic structure while each pulse alone will be strongly reflected due to the Bragg reflection. Based on the results, we present a new all-optical switching scheme and investigate its operational characteristics.
How to measure MTF
Authors: Carellas Peter , Wilk Stephen
Published: February 2023

Modulation transfer function (MTF) is quickly becoming a popular method of determining the quality of optical systems. We discuss various methods currently used to measure MTF, from traditional target projections to new video-based real-time systems. A sampling of actual and theoretical MTF test results are discussed for general and specific applications.
Efficient upconversion by a frequency factor between 2 and 3 using an OPO
Authors: Moore Gerald T. , Koch Karl
Published: February 2023

We consider a device for frequency up-conversion from pump frequency ω
p
to a desired frequency ω
d
between 2ω
p
and 3ω
p
.
Two-color photo-associative ionization: observing intermediate steps of ultracold atomic collisions
Authors: Bagnato V. , Marcassa L. , Tsao C. , Wang Y. , Weiner J.
Published: February 2023

Photo-associative ionization in sodium atoms has been the first two-body collision process investigated in optical traps.1
Dynamics of photoprocesses in the adsorbed state
Authors: Polanyi John C.
Published: February 2023

Photochemistry has always been appealing to chemists since they can select the bonds to be broken and, with pulsed ultraviolet light, can initiate photoinduced processes at a well-defined time.
InGaAlP visible-light laser diodes
Authors: Itaya K. , Hatakoshi G.
Published: February 2023

Considerable progress has been made in the development of short-wavelength InGaAlP visible light laser diodes. This paper describes problems and our achievements in the design and fabrication of InGaAlP lasers.
Prospects for blue–green diode lasers based on wide-bandgap III–V materials
Authors: Khan Asif , Pankove Jacques
Published: February 2023

Blue-green diode lasers are a subject of intense research activity. The interest is sparked by the potential of numerous commercial and defense applications.
Novel structures for efficient frequency conversion
Authors: Fejer Martin
Published: February 2023

Summary not available.
Comparison of angle-multiplexed, wavelength-multiplexed, and phase-coded holographic memories
Authors: Curtis Kevin , Burr Geoffrey W. , Psaltis Demetri
Published: February 2023

Multiple holograms can be recorded in a material by changing either the reference beam angle [1] (θ multiplexing), the recording wavelength [2] (λ multiplexing) or by phase coding multiple plane wave reference beams [3].
Electrical fixing of photorefractive holograms in SBN:75 crystals: experiments and theory
Authors: Qiao Yong , Orlov Sergei , Psaltis Demetri
Published: February 2023

We report the experimental demonstration of electrical fixing of photorefractive holograms in SBN:75 crystals.
Comparison of time- and frequency-domain adaptive-filtering algorithms
Authors: Berinato Robert J. , Abushagur Mustafa A.G.
Published: February 2023

Adaptive signal processing technology has advanced rapidly in terms of both algorithms and hardware.
Optical time-integrating wavelet-transform processor
Authors: Subotic Nikola S. , Aleksoff Carl C.
Published: February 2023

A new representation of information that has garnered considerable recent interest is the wavelet distribution of data.
Rod contribution to the 10° color-matching functions
Authors: Shapiro Arthur G. , Pokorny Joel , Smith Vivianne
Published: February 2023

Differences among sets of color matching functions occur both between (Stiles and Burch, 1959) and within individuals (Crawford, 1965; Zaidi, 1986; Thornton, 1992)
Monochromatic tritan metamers
Authors: Pokorny Joel , Smith Vivianne C.
Published: February 2023

At the 1992 meeting of CIE Committee TC-136, two sets of cone fundamentals were considered; the Smith and Pokorny fundamentals based upon the Judd revised Standard Observer and a set proposed by Stockman and MacLeod based on the mean Stiles 2 deg pilot data.
Switching, lasers, and propagation in tailored EDFAs
Authors: Islam Mohammed N.
Published: February 2023

Erbium-doped fiber amplifiers (EDFA’s) have already made a large impact in fiber transmission systems, and they are also beginning to penetrate nonlinear optical applications.
Learning dynamics in optical neural networks
Authors: Psaltis Demetri
Published: February 2023

Supervised training algorithms for multi-layer networks can be divided into two broad categories: local and global.
Light scattering in dental hard tissues
Authors: Fried Daniel , Featherstone John D. B. , Seka W. , Glena Dick , Bordyn Brett
Published: February 2023

The angular distribution of scattered laser light was measured at 543 nm, 632 nm, and 1053 nm through 30-1500 micron sections of enamel and dentin.
Steady-state versus frequency-domain techniques for the determination of tissue optical properites
Authors: Madsen Steen J. , Tromberg Bruce J. , Svaasand Lars O. , Haskell Richard C.
Published: February 2023

The optical properties of representative biological tissues have been determined ex vivo by using steady-state and frequency-domain techniques.
Plane-wave pulse propagation in a linear, causally dispersive polar medium
Authors: Laurens Judith E. K. , Oughstun Kurt E.
Published: February 2023

The asymptotic description of plane-wave electromagnetic pulse propagation in a causal, dispersive polar dielectric medium is presented.
Effect of beam ellipticity on the mode-locking process in Ti:sapphire lasers
Authors: Bridges Robert E. , Boyd Robert W. , Agrawal Govind P.
Published: February 2023

We investigate numerically and experimentally the effects of beam ellipticity on modelocking in the Ti:sapphire laser.
Quantum theory of microcavity semiconductor lasers and spontaneous decay rate of excitons in a dielectric medium
Authors: Ho Seng-Tiong
Published: February 2023

The derivation of the quantum theory of lasers from first principle given in the literature is usually fairly long and complex.
Real time training of the optical face recognition network
Authors: Li Hsin-Yu S. , An Xin , Psaltis Demetri
Published: February 2023

We present a two layer optical network that accepts and “learns” input images of faces in real time, and then classify them at standard video rates.1
Intrapreneurship
Authors: Leonberger Fred
Published: February 2023

Dr. Leonberger will discuss intrapreneurship, or how to create a subsidiary to commercialize a technology developed in a big company.
The business and financial aspects of a consulting business
Authors: MacVicar Duncan
Published: February 2023

Mr. MacVicar will discuss the reality of being an independent consultant. He will discuss the business and financial aspects of a consulting business.
Memory use during hand-eye coordination
Authors: Hayhoe Mary M. , Ballard Dana H. , Whitehead Steven D. , Pelz Jeff B.
Published: February 2023

One of the most fundamental features of human cognitive function is the limited nature of the attentional and short term memory resources that can be brought to bear on the performance of a task.
Visual coding of contour form: the role of high- and low-level constraints
Authors: Knill David C.
Published: February 2023

The visual system has limited resolution with which to code image information; therefore, it must selectively allocate coding resources to (1) maximize the information transmitted to later stages of processing, and (2) selectively code those features of image data which are functionally important to an organism (e.g. for the estimation of 3D shape).
LiNbO3-waveguide QPM-SHG devices with domain-inverted gratings formed by electron-beam scanning
Authors: Suhara T. , Fujimura M. , Nishihara H.
Published: February 2023

The key technology for implementing waveguide QPM-SHG devices is formation of domain-inverted gratings.
Spectroscopic ellipsometry measurements of the optical functions of thin films
Authors: Jellison G. E. , Boatner L. A. , Lowndes D. H. , McKee R. A. , Godbole M.
Published: February 2023

A procedure has been developed to determine the optical functions of thin films from spectroscopic ellipsometry data.
Enhanced Raman scattering in attenuated total reflection
Authors: Jhe W. , Lee M. G. , Lee J. H. , Chang J. S.
Published: February 2023

It is well known that surface plasmons (SP) can propagate for about five hundred micrometers in the visible if there are identical dielectric materials on both sides of a thin metallic film.
Measurement of the triplet lifetime of dye molecules by using frequency-domain absorption measurements
Authors: Göktürk Halit S. , Hart Timothy R.
Published: February 2023

The lifetime of the forbidden transition between the lowest lying triplet state and the ground state of a dye molecule is generally measured using a dual pump arrangement, whereby, one laser is used to create a triplet population and the second laser to probe the absorption between the triplet states [1].
Ridge-waveguide InGaAs/GaAs single-quantum-well lasers with an in-cavity quasi- phase-matched Al1-x/GaxAs multilayer heterostructure for surface-emitted sum- frequency mixing
Authors: Dai H. , Buchanan M. , Delage A. , Janz S. , Normandin R.
Published: February 2023

Surface-emitting second harmonic generation based on nonlinear integration of counter-propagating waves in a quasi-phase-matched Al1-xGaxAs multilayer waveguide has potential applications in novel optoelectronic devices such as integrable opti-G channel are broader than that of those achromatic channel (30°-15°:Phillips & Wilson, JOSA, 1984).
Waveguide holography for optical pattern recognition
Authors: Chennankara B. , Xu W.-Y. , Lin F. C. , Drake M. D. , Fiddy A.
Published: February 2023

There has been much interest recently in the use of an edge-illuminated or waveguide hologram for both display and information processing applications.
Period doubling and chaos in additive-pulse mode-locked lasers
Authors: Sucha G. , Bolton S. R , Weiss S. , Chemla D. S.
Published: February 2023

We have observed period-doubling and the period-doubling route to chaos in an additive-pulse mode-locked (APM) color-center laser. The period-doubling behavior, which manifests itself as a train of pulses with alternating pulse heights, is stable, robust, and can be quite pronounced, with up to a 50% difference in pulse energies. Unless one monitors the pulse train carefully, this effect can go undetected because the pulse autocorrelation and optical spectrum give no apparent evidence that this behavior is occurring.
Chaos and instabilities in lasers
Authors: Glorieux Pierre
Published: February 2023

By varying the Fresnel number and the stability of the laser cavity, it has been possible to study the onset of spatial (and spatiotemporal) complexity in a CO2 laser.
Comparison of three 3-D imaging techniques
Authors: Jones Peter F. , Aitken George J. M.
Published: February 2023

An important practical consideration in designing an electronic three-dimensional (3-D) imaging system is the amount of data that must be detected, post-processed and transmitted. A key parameter governing the amount of data is the number of 3-D resolution cells within a given field of view.
Light scattering by microdroplets with internal structure
Authors: Fuller Kirk A.
Published: February 2023

Recent developments in the theory of light scattering by compound spherical domains allow one to calculate the optical properties of micron-sized spherical particles possessing internally dispersed subspheres. The theoretical treatment of such a problem will be outlined and numerical results will be provided. Data taken from microwave scattering experiments on such particles will also be presented. In addition to comparing theory with experiment, scattering and absorption cross sections pertaining to atmospheric radiation and combustion diagnostics will be considered, as will the effects of internal structure on morphology dependent resonances of microspheres. This research was supported in part by the National Science Foundation and the National Parks Service.
Simultaneous elastic and spontaneous Raman scattering by homogeneous and layered microdroplets
Authors: Ray A. K. , Das B.
Published: February 2023

Elastic and Raman scattering data from single homogeneous or layered microdroplets suspended in an electrodynamic balance have been obtained by scanning a tunable ring dye laser, Wavelengths of transverse magnetic (TM) and transverse electric (TE) mode resonances in light scattered elastically by a droplet have been measured independently by using two detectors in the planes parallel and perpendicular to the plane of polarization. Simultaneously, Raman scattered light at a fixed wavenumber shift has been measured. Using an alignment procedure, differences between the observed and theoretical positions of TE and TM mode resonances are minimized to obtain size and wavelength-dependent refractive index of homogeneous and layer droplet. The procedure permits absolute size and refractive index determination with relative errors of 3 x 10-5, and detection of a monolayer on a droplet. The size and refractive index data are used to analyze observed resonances in Raman scattering. Results show that all resonances having theoretical FWHM less than 1.0 x 10-4 cm-1 appear in Raman spectra. Even though theoretical widths of the resonances observed in Raman spectra are extremely narrow, experimental peaks are found to have widths no less than 0.20 cm-1. The observed peak broadening and heights can not be explained by absorption but suggests an oscillation of droplet size by about 5 A.
How to win and manage contracts with emphasis on SBIR
Authors: Tanimoto Douglas
Published: February 2023

Dr. Tanimoto will describe a corporate strategy of using government funded research to develop products for diversifying a business. He will describe how to win and manage contracts with emphasis on SBIR.
Multidimensional broadcast networks
Authors: Sharony Jacob , Li Yao
Published: February 2023

One-dimensional broadcast networks are common, e.g., in the space dimension we have the crossbar networks, and in the wavelength dimension we have the star-based networks (e.g., “broadcast and select”). These networks have limited connectivity: the space-division networks are limited by the switch count and complexity of control, and the wavelength-division networks have a relatively small number of wavelength-channels due to spectrum limitation. In the proposed k-dimensional networks,1 a communication channel between input and output is consists of k coordinates, one per dimension. Each input in the network broadcasts its fixed k coordinates to all the outputs. A connection is established when an output selects the appropriate coordinates (one per dimension) of a specific input. These networks are strictly non-blocking and have very high connectivity (>>1000) using only several dimensions (say 3). The high connectivity is achieved by relaxing the constraints on the size of each dimension since several dimensions share the load of the network, e.g., a 3-dimensional network with connectivity 1000 would require only 10 channels in each dimension. The network is optimal in essence that its complexity achieves the information lower bound through hierarchical multiplexing. An example of a 3-idimensional optical-wavelength, microwave-frequency and space is described and compared with some traditional networks.
Interference of laser modes: observations at the single-photon level
Authors: Hariharan P. , Brown Nick , Sanders Barry C. , Fujima Ichiro
Published: February 2023

The accuracy of earlier experiments on the interference of independent laser beams at the single-photon level has been limited by the very short observation times. We have overcome this problem by observing the beats produced by the two orthogonally polarized modes from a frequency-stabilized transverse Zeeman laser.
QND measurements and wave function collapse in penning traps
Authors: Marzoli Irene , Tombesi Paolo
Published: February 2023

The attained precision of measurements in Penning traps is so high that, for light particles, the relativistic corrections are detectable. Thus, the coupling among the various motions of the trapped particle is provided by the relativistic shift of the mass. A parallel LCR circuit interacting with the elastically bound particle represents the measurement device. The measurement is performed by monitoring the resonance frequency of the spectral function of the output voltage.
Recent advances in Cr4+-doped tunable solid-state lasers
Authors: Petricevic V. , Alfano R. R.
Published: February 2023

A comprehensive review of the performance of chromium-doped fosterite (Cr:Mg2SiO4), the first solid-state laser based on tetravalent chromium (Cr44) as a lasing ion, will be presented. Different modes of operation ranging from room-temperature gain-switched to cryogenic continuous-wave operation will be reviewed. Various methods for generation of femtosecond pulses will also be presented. The potential of utilizing Cr4+ ion-doped crystals for tunable solid state lasers in the l-2pm spectral region as well as various possible applications will be discussed. Future development of Cr4+-based lasers including some particularly attractive modes of operation such as mode-locked and diode-pumped operation will also be discussed.
Characterization of a continuous-wave chromium-doped YAG laser
Authors: Sennaroglu Alphan , Pollock Clifford R. , Nathel Howard
Published: February 2023

Chromium-doped YAG (Cr:YAG) laser, first demonstrated by Shestakov et al.[1], is a recently developed solid-state laser source tunable in the wavelength region around 1.4 µm. We describe here a detailed characterization of this laser system pumped by a continuous-wave Nd:YAG laser. The experiments were performed using a 2 cm long Brewster-angled Cr:YAG crystal with 93% absorption at 1.06 µm, placed in an astigmatically compensated z-cavity. Using a 2% transmitting output coupler and approximately 5.2 W of absorbed pump power, output powers as high as 1.1 W have been obtained. Data showing the dependence of the ouput power on crystal temperature, absorbed pump power and wavelength will be presented and the overall cw performance of this laser system will be compared with chromium-doped forsterite and NaCl:OH lasers.
Multislice forward modeling of coherent surface scattering imaging on surface and interfacial structures
Authors: Myint Peco , Chu Miaoqi , Tripathi Ashish , Wojcik Michael J. , Zhou Jian , Cherukara Mathew J. , Narayanan Suresh , Wang Jin , Jiang Zhang
Published: February 2023

To study nanostructures on substrates, surface-sensitive reflection-geometry scattering techniques such as grazing incident small angle X-ray scattering are commonly used to yield an averaged statistical structural information of the surface sample. Grazing incidence geometry can probe the absolute three-dimensional structural morphology of the sample if a highly coherent beam is used. Coherent surface scattering imaging (CSSI) is a powerful yet non-invasive technique similar to coherent X-ray diffractive imaging (CDI) but performed at small angles and grazing-incidence reflection geometry. A challenge with CSSI is that conventional CDI reconstruction techniques cannot be directly applied to CSSI because the Fourier-transform-based forward models cannot reproduce the dynamical scattering phenomenon near the critical angle of total external reflection of the substrate-supported samples. To overcome this challenge, we have developed a multislice forward model which can successfully simulate the dynamical or multi-beam scattering generated from surface structures and the underlying substrate. The forward model is also demonstrated to be able to reconstruct an elongated 3D pattern from a single shot scattering image in the CSSI geometry through fast-performing CUDA-assisted PyTorch optimization with automatic differentiation.
Characterizing non-polarization-maintaining highly nonlinear fiber toward squeezed-light generation
Authors: Chapman Joseph C. , Peters Nicholas A.
Published: February 2023

Squeezed light, which is easily degraded by loss, could benefit from generation directly in optical fiber. Furthermore, highly nonlinear fiber could offer more efficient generation with lower pump power and shorter fiber lengths than standard single-mode fiber. We investigate non-polarization-maintaining highly nonlinear fiber (HNLF) for squeezed-light generation by characterizing possible sources of excess noise, including its zero-dispersion wavelength (ZDW) variation and polarization noise. We find significant ZDW variation and excess polarization noise. We believe the polarization noise is from non-linear polarization-mode dispersion. We model this polarization noise and find that it is likely to degrade Kerr squeezing but not squeezing from four-wave mixing.
Investigating centrifugal filtration of serum-based FTIR spectroscopy for the stratification of brain tumours
Authors: Theakstone Ashton G. , Brennan Paul M. , Jenkinson Michael D. , Goodacre Royston , Baker Matthew J.
Published: February 2023

Discrimination of brain cancer versus non-cancer patients using serum-based attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy diagnostics was first developed by Hands et al with a reported sensitivity of 92.8% and specificity of 91.5%. Cameron et al. then went on to stratifying between specific brain tumour types: glioblastoma multiforme (GBM) vs. primary cerebral lymphoma with a sensitivity of 90.1% and specificity of 86.3%. Expanding on these studies, 30 GBM, 30 lymphoma and 30 non-cancer patients were selected to investigate the influence on test performance by focusing on specific molecular weight regions of the patient serum. Membrane filters with molecular weight cut offs of 100 kDa, 50 kDa, 30 kDa, 10 kDa and 3 kDa were purchased in order to remove the most abundant high molecular weight components. Three groups were classified using both partial least squares-discriminate analysis (PLS-DA) and random forest (RF) machine learning algorithms; GBM versus non-cancer, lymphoma versus non-cancer and GBM versus lymphoma. For all groups, once the serum was filtered the sensitivity, specificity and overall balanced accuracies decreased. This illustrates that the high molecular weight components are required for discrimination between cancer and non-cancer as well as between tumour types. From a clinical application point of view, this is preferable as less sample preparation is required.
Estimation of the economic benefits for the public health system related to salt reduction in Costa Rica
Authors: Vega-Solano Jaritza , Madriz-Morales Karol , Blanco-Metzler Adriana , Fernandes-Nilson Eduardo Augusto
Published: February 2023

Excessive salt and sodium intake are strongly associated with high blood pressure and increased risk of cardiovascular disease. High blood pressure in turn is the main risk factor for the global burden of morbidity and mortality. The prevalence of this disease in the adult population of Costa Rica in 2018 was 37.2%. Costa Rica has limited information on the economic costs for the public health system and related of the prevalence of this type of disease mediated by dietary factors such as salt intake. Objective: to estimate the economic benefits for the public health system related to salt reduction in Costa Rica for the year 2018. Methodology: estimation of the economic benefits for the public healthcare costs and productivity losses associated to reducing the per capita salt consumption of Costa Ricans to 5g/day, including the estimation of the Years of Life Productive Lost and of the direct costs on consultations, hospitalizations, and medications for the Costa Rica Social Security System. Results: The total annual costs of hospitalization, consultations, and medications attributable to excessive salt intake in the population older than 15 years of age for the year 2018, were estimated at USD $15.1 million. The highest were in hospitalizations (53%), followed by consultations and medications (32% and 15%, respectively). Conclusion: NCDs caused by excessive salt intake represent important economic losses for the country, not only in terms of direct health costs, but also indirect due to the increase in years of potential life lost due to premature deaths because of CVD, which causes significant losses of human capital and, therefore, to the economy and the development of Costa Rica.
Compatibility effects with destination and origin of motion
Authors: Scerrati Elisa , Nicoletti Roberto , Rubichi Sandro , Scorolli Claudia , Lugli Luisa
Published: February 2023

Previous studies highlighted spatial compatibility effects other than those strictly arising from stimulus-response locations. In particular, the so-called Destination Compatibility (DC) effect refers to faster responses for dynamic (i.e., moving) stimuli the end point of which is spatially compatible with the response key. Four experiments examined whether the DC effect also occurs with static visual stimuli symbolically representing either motion destination alone (Experiment 1a), or both motion origin and destination (Experiments 1b, 2a, and 2b). Overall, our results are consistent in showing a DC effect; most importantly, the present findings reveal a predominance of the effect of destination of motion over that of origin, even when both the starting and ending positions of the stimulus are symbolically represented and participants are instructed to respond according to motion origin. This finding suggests that the DC effect is independent from other stimulus-response compatibility (SRC) effects.
Effectiveness, acceptability, and feasibility of technology-enabled health interventions for adolescents living with HIV in low- and middle-income countries: A systematic review protocol
Authors: Crowley Talitha , Petinger Charne , van Wyk Brian
Published: February 2023

Adolescents living with chronic conditions such as HIV (ALHIV) are challenged to remain adherent and engaged in HIV care. Technology offers a promising platform to deliver behaviour-change interventions to adolescents. The largest proportion of ALHIV resides in sub-Saharan Africa; yet little is known about the effectiveness, feasibility and acceptability of technology-enabled interventions to deliver and support health care to ALHIV in resource-constraint settings. This study aims to explore the literature and synthesise the evidence for the effectiveness, acceptability, and feasibility of technology-enabled health interventions for ALHIV in low and middle-income countries (LMIC). Eight electronic databases (Ebscohost, CINAHL, ERIC, MEDLINE, PubMed, SCOPUS, Science Direct, and Sabinet) and Google Scholar will be searched to identify technology-enabled health interventions for ALHIV in LMIC published from 2010–2022. Quantitative and qualitative studies reporting on technology-enabled health interventions for predominantly adolescents (10–19 years) will be included. The review will be performed, and findings reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols. A two-stage process of screening titles and abstracts, and then full-text, will be performed independently by two reviewers. The quality of the included studies will be assessed using the Critical Appraisal Skills Programme checklists, and the Risk of Bias in Non-randomised Studies of Interventions tool will be used to assess the risk of bias. The review will involve publications already in the public domain; therefore, ethics approval is not required. The results will be disseminated through a peer-reviewed journal publication and/or conference proceedings.

PROSPERO registration number: CRD42022336330.
The impact of resection margin distance on survival and recurrence in pancreatic ductal adenocarcinoma in a retrospective cohort analysis
Authors: Obonyo Dennis , Uslar Verena Nicole , Münding Johanna , Weyhe Dirk , Tannapfel Andrea
Published: February 2023

Background

The prognostic effect of resection margin status following pancreatoduodenectomy for pancreatic ductal adenocarcinoma (PDAC) remains controversial, even with the implementation of standardized pathological assessment. We therefore investigated the impact of resection margin (RM) status and RM distance in curative resected PDAC on overall survival (OS), disease-free survival (DFS) and recurrence.

Method

108 patients were retrieved from a prospectively maintained database of a certified pancreatic cancer center. Distribution and relationships between circumferential resection margin (CRM) involvement (CRM≤1mm; CRM>1mm; CRM≥2mm) and their prognostic impact on OS and DFS were assessed using Kaplan-Meier statistics and the Log-Rank test. Multivariate logistic regression was used explain the development of a recurrence 12 months after surgery.

Results

63 out of 108 patients had medial RM and 32 posterior RM involvement. There was no significant difference in OS and DFS between CRM≤1mm and CRM>1mm resections. Clearance at the medial margin of ≥2mm had an impact on OS and DFS, (RM≥2mm vs. RM<2mm: median OS 29.8 vs 16.8 months, median DFS 19.6 vs. 10.3 months). Multivariate analysis demonstrated that age, medial RM ≥2mm, lymph node status and chemotherapy were prognostic factors for OS and DFS. Posterior RM had no influence on OS or DFS.

Conclusion

Not all RM seem to have the same impact on OS and DFS, and a clearance of 1mm for definition of a negative RM (i.e. CRM>1mm) seems not sufficient. Future studies should include more patients to stratify for potential confounders we could not account for.

Trial registration

This study was registered with the German Clinical Trials Registry (reference number DRKS0017425).
Longitudinal assessment of HCV core antigen kinetics to monitor therapeutic response in the age of DAAs
Authors: Ponnuvel Suresh , Prakash Arul , Steve Runal John , Doss George Priya , Goel Ashish , Zachariah Uday George , Eapen Chundamannil Eapen , Rebekah Grace , Kannangai Rajesh , Fletcher Gnanadurai John , Abraham Priya
Published: February 2023

Background

In the economy of therapeutic monitoring, an affordable viral marker is essential in the era of direct-acting antivirals (DAAs). We elucidated the kinetics of HCVcAg to delineate its precise role in monitoring therapeutic response.

Methods

In this longitudinal study, 3208 patients were tested for HCV RNA. A total of 423 patients were started on DAAs. Treatment response and kinetics of HCVcAg/RNA were assessed in treatment-naïve (n = 383) and previously treated (n = 40) patients with follow-up for 2 years.

Results

After the initiation of DAAs, the rate of relapse was significantly higher in the previously treated group than naive group [12.5% (5/40) Vs 2% (7/383), p<0.0001]. The response rate at RVR was significantly higher with HCVcAg than RNA in both groups (p<0.02). The kinetics of HCVcAg and RNA were significantly different at ETR and SVR12 in the naïve (p<0.04), but similar at all therapeutic points in the previously treated group. The correlation between HCVcAg and RNA was good at baseline, ETR and SVR, except RVR in both groups (r>0.6; p<0.0001). Furthermore, HCV genotypes, treatment regimen, CTP (<7/≥7) and MELD (<15/≥15) did not influence the therapeutic response and the viral replication kinetics (p>0.05).

Conclusions

It is the first longitudinal study from India shows that the response rate and kinetics of HCVcAg are comparable to HCV RNA for an extended duration, except at RVR, irrespective of the HCV genotypes, treatment regimen, and liver disease severity. Hence, HCVcAg can be considered as a pragmatic marker to monitor therapeutic response and predict relapse in the era of DAAs.
Wbm0076, a candidate effector protein of the Wolbachia endosymbiont of Brugia malayi, disrupts eukaryotic actin dynamics
Authors: Mills Michael K. , McCabe Lindsey G. , Rodrigue Eugenie M. , Lechtreck Karl F. , Starai Vincent J.
Published: February 2023

Brugia malayi, a parasitic roundworm of humans, is colonized by the obligate intracellular bacterium, Wolbachia pipientis. The symbiosis between this nematode and bacterium is essential for nematode reproduction and long-term survival in a human host. Therefore, identifying molecular mechanisms required by Wolbachia to persist in and colonize B. malayi tissues will provide new essential information regarding the basic biology of this endosymbiosis. Wolbachia utilize a Type IV secretion system to translocate so-called “effector” proteins into the cytosol of B. malayi cells to promote colonization of the eukaryotic host. However, the characterization of these Wolbachia secreted proteins has remained elusive due to the genetic intractability of both organisms. Strikingly, expression of the candidate Wolbachia Type IV-secreted effector protein, Wbm0076, in the surrogate eukaryotic cell model, Saccharomyces cerevisiae, resulted in the disruption of the yeast actin cytoskeleton and inhibition of endocytosis. Genetic analyses show that Wbm0076 is a member of the family of Wiskott-Aldrich syndrome proteins (WAS [p]), a well-conserved eukaryotic protein family required for the organization of actin skeletal structures. Thus, Wbm0076 likely plays a central role in the active cell-to-cell movement of Wolbachia throughout B. malayi tissues during nematode development. As most Wolbachia isolates sequenced to date encode at least partial orthologs of wBm0076, we find it likely that the ability of Wolbachia to directly manipulate host actin dynamics is an essential requirement of all Wolbachia endosymbioses, independent of host cell species.
Turismo de cafés no Caparaó pela perspectiva do potencial turista
Authors: Carvalho Tavares Beatriz , Losso Flavia Baratieri
Published: February 2023

Localizada nos estados de Minas Gerais e Espírito Santo, a região do Caparaó apresenta crescente importância como destino turístico relacionado ao café. Muitos consumidores de cafés especiais e profissionais da área a visitam motivados pela cultura cafeeira local e pela associação da imagem da região ao produto de qualidade, da agricultura familiar e com De[1]nominação de Origem. Esta pesquisa teve como objetivo compreender o perfil do potencial turista de cafés na região do Caparaó. De caráter qualitativo, exploratório e descritivo, este estudo contou com percurso metodológico dividido em duas etapas principais: bibliográfica e coleta de dados. A primeira etapa versou sobre a revisão de literatura em bases de dados nacionais e internacionais sobre a temática do comportamento do consumidor no turismo e sobre o perfil do turista de cafés. A segunda etapa consistiu na coleta de dados por meio de questionário com consumidores de café e entrevistas semiestruturadas online com pro[1]prietários de torrefações que trabalham exclusivamente com cafés especiais da região do Caparaó. Entre os resultados, foram identificados dois principais grupos potenciais de tu[1]ristas de cafés: os coffee lovers (apreciadores) e os traders (empreendedores). Apesar de distintas, as características do comportamento de consumo desses públicos atuam conjun[1]tamente em benefício do desenvolvimento econômico local e da valorização dos aspectos sociais, culturais e ambientais do território.
Transformaciones ambientales derivadas del metabolismo turístico residencial en Malinalco, Estado de México
Authors: Gómez Barranco Leny Beatríz , Elva Esther Vargas Martínez
Published: February 2023

Malinalco es un destino mexicano que presenta un notable desarrollo turístico regional, con ello se ha alterado su metabolismo natural, el cual está relacionado con la forma en que adquiere y hace uso de los recursos para satisfacer las necesidades humanas. El objetivo de la presente investigación es analizar el metabolismo de la actividad turística residencial en Malinalco a partir de los patrones de consumo, transformación y excreción de recursos naturales que determinan su transformación ambiental. Se utilizó el método MUSIASEM, para evaluar datos biofísicos de tres recursos naturales: tierra, agua y energía, y relacionar[1]los con las transformaciones ambientales que presenta el destino. Dicha información se integró a partir de la investigación documentada y de entrevistas en profundidad realiza[1]das a diversos actores clave. Los resultados muestran que la actividad turística residencial cuadriplica el consumo de recursos naturales transformando el ambiente, especialmente por el aumento de uso de tierras destinadas a proyectos inmobiliarios, los cuales emplean grandes cantidades de agua y energía, ocasionando fuertes presiones ambientales. Como resultado de la contabilidad biofísica se percibe un lento pero eminente deterioro ambiental resultado de una dicotomía entre la urbanización turístico-residencial y la naturaleza; por lo que es necesario reorientar las tendencias del turismo hacia prácticas y servicios más sustentables.
Chronic pain and functional impairment after arthroscopic surgery for a knee injury
Authors: Khlaboshchina V. N. , Karateev A. E. , Makarov M. A. , Filipsky N. S. , Naryshkin E. A. , Nesterenko V. A. , Lila A. M.
Published: February 2023

Arthroscopic interventions are widely used to treat the consequences of the meniscus and anterior cruciate ligament (ACL) injuries. However, the long-term consequences of these surgeries are not always favorable and not in all cases allow to avoid the development of chronic pain and posttraumatic osteoarthritis.Objective: to evaluate the incidence of persistent postoperative pain and the persistence of functional disorders in patients undergoing arthroscopic interventions on the menisci and ACL.Material and methods. The study group consisted of 147 patients (60 women and 87 men, mean age 38.8±12.5 years) who underwent arthroscopic surgery on the knee joint (KJ) in the traumatology and orthopedic department of V.A. Nasonova Research Institute of Rheumatology in 2018– 2021. The condition of patients was assessed by telephone survey and/or online questionnaire. The pain and fatigue levels were assessed on numerical rating scale (NRS, 0–10), as well as the severity of functional disorders on the Lysholm scale (LS).Results and discussion. Moderate or intense knee pain and increased fatigue (≥4 according to NRS) were noted in 11.3% and 14.7% of respondents, respectively. The state of the KJ according to LS in 35.3% of patients was assessed as excellent (95–100 points), in 29.3% – as good (84–94 points), in 21.3% – as satisfactory (65–83 points) and 14.0% – as unsatisfactory (≤64 points).Conclusion. More than 10% of patients after arthroscopic operations on the knee joint experience moderate or severe pain and fatigue, satisfactory and unsatisfactory functional results are observed in 35.4% of cases.
Clinical case of SARS-CoV-2 infection in a patient with rheumatoid arthritis and secondary AA-amyloidosis of the lungs
Authors: Vorobeva O. V. , Romanova L. P.
Published: February 2023

In rheumatic diseases, the risk of infections development is higher than in the general population. The article describes a case of SARS-CoV-2 infection in a patient with rheumatoid arthritis (RA) and secondary AA-amyloidosis of the lungs, which led to a fatal outcome. In the context of the COVID-19 pandemic, RA patients with secondary AA-amyloidosis and pulmonary fibrosis are likely to represent a special risk group for developing a severe course of this infection with a fatal outcome.