bluuebunny/crossref_metadata_2025 huggingface dataset:
An Integrated Approach to the Design and Maintenance of Pneumatic Power Systems
Authors: Kong K. K. , Chuen C. W. , Leung T. P. , Wong T. T.
Published: September 2024

An integrated knowledge representation for the design, diagnosis and maintenance of physical systems has been developed. This approach can minimize the redundancy of represented knowledge in building expert systems for the design and maintenance of physical systems. In the knowledge of human beings, the design knowledge, diagnosis knowledge and maintenance knowledge of the physical systems are integrated and can be retrieved as required. A thorough analysis on the knowledge of human beings has been carried out in order to determine the critical points which enable the human beings to design, diagnose and maintain physical systems. “Change Theory” is developed to explain the natures of knowledge and the relations among design, diagnosis and maintenance knowledge of physical systems. The natures of knowledge consist of sensation-state-change identification and sensation-state-change initiation. The clustering of the state changes gives rise to different types of knowledge. An integrated knowledge representation for building expert systems is developed with features that keep the redundancy of represented knowledge to a minimum. These features are: i) the knowledge base of the expert system is separated into the knowledge of entities and the knowledge of manipulating the entities; and ii) the inference engine of the expert system is context dependence, which retrieves the corresponding knowledge by checking the preference and non-preference status of the states of the entities. The developed methodology is implemented on an expert system which exhibits design, diagnosis and maintenance of pneumatic power systems.
Nonlinear Optimal Control of a Hydraulically Actuated Positioning System
Authors: McLain Timothy W. , Beard Randal W.
Published: September 2024

In this paper, the nonlinear optimal control problem is formulated for the position control of an electrohydraulic servo system. The optimal control is given by the solution to the Hamilton-Jacobi-Bellman equation, which in this case cannot be solved explicitly. An alternative method, based upon successive Galerkin approximation, is used to obtain an approximate optimal solution. Preliminary simulation results, demonstrating the application of this approach to the position control of a hydraulically actuated device, are presented.
Robust Controller Design for a Variable Displacement Hydraulic Motor
Authors: Plahuta Michael J. , Franchek Matthew A. , Stern Hansjoerg
Published: September 2024

Presented in this paper is the robust control of a variable displacement hydraulic motor (VDHM). A feedback control structure consisting of two nested loops is employed. The inner feedback loop controls the position of the rocker arm which actuates the wobbler plate of the motor. The outer feedback loop regulates the motor shaft velocity such that shaft speed is guaranteed at steady state despite external torque loads. The control loops are closed in succession closing the inner loop first. For each loop design, step response data is collected from a VDHM laboratory test stand to generate analytical systems level models. Based on these models, feedback controllers are designed using classical loop shaping techniques. Feedback control, as opposed to feedforward control, maintains motor shaft velocity under nonpredictive torque loading conditions. In addition, the feedback structure eliminates the need for extensive system calibration when considering system parameter changes that result from component aging.
Nonlinear Adaptive Robust Control of One-DOF Electro-Hydraulic Servo Systems
Authors: Yao Bin , Chiu George T.-C. , Reedy John T.
Published: September 2024

This paper intends to provide a theoretic framework for the high performance robust control of electro-hydraulic servo-systems. This is achieved through applying the recently proposed adaptive robust control (ARC) while taking into account the particular nonlinearities and model uncertainties of the electro-hydraulic servo-systems. In particular, the robust motion control of a typical electro-hydraulic servo-system will be considered. The system consists of an inertia load driven by a double rod cylinder regulated by a two-stage servovalve. The paper will consider the effect of both parametric uncertainties coming from the inertia load and the cylinder and the uncertain nonlinearities such as friction forces. Non-differentiability of the inherent nonlinearities associated with hydraulic dynamics is examined and strategies are provided for handling the non-differentiability of the control term due to the direct change of valve opening when doing backstepping design via ARC Lyapunov function. The resulting controller guarantees a prescribed transient performance and final tracking accuracy in the presence of both parametric uncertainties and uncertain nonlinearities while achieving asymptotic tracking in the presence of parameteric uncertainties.
Osmomechanical Behavior of Plant Cells Across Regions of Elastic and Osmotic Stress
Authors: Walsh John R. , Diller Kenneth R. , Brand Jerry J.
Published: September 2024

Currently, we are developing protocols for cryopreserving select strains of algae from a large culture collection. Protocol design processes for specific organisms involve modeling the coupled osmomechanical behavior of the cells during cryoprotective additive (CPA) exposure. Perfusion cryomicroscopy experiments were conducted to characterize the extent of elastic and osmotic coupling effects upon cell volume changes during exposure of Chlorococcum texanum to step changes in extracellular sucrose concentration. Volume data obtained off-line from video recordings of continuous volumetric changes was combined with inverse solution methods to obtain constitutive property data which includes the cell wall/membrane permeability coefficient for water and the cell wall elastic behavior. Network thermodynamic modeling was employed to simulate the coupling of the elastic and osmotic effects of an algal cell during CPA perfusion. Results from perfusion experiments indicate that a decoupling of elastic and osmotic stresses occurs at the point of incipient plasmolysis. The objective of this study is to construct a robust model of the coupled elastic-osmotic behavior of the algal cells to accurately simulate the volumetric response of algal cells as changes in extracellular solute concentration are encountered during cryopreservation, including severe shrinking and swelling of cells. Volumetric predictions require accurate modeling of the osmomechanical behavior across both elastic and osmotic regimes as well as the transition region of incipient plasmolysis where elastic and osmotic stresses become uncoupled.
Selective Multilayer Thin-Film Development in Insects
Authors: Miaoulis Ioannis N. , Tada Haruna , Mann Seth , Wong Peter Y.
Published: September 2024

Multilayer structures of biological thin films play numerous roles in insects, plants, lizards, and birds. Due to microscale radiative effects, small changes in the film thicknesses result in large changes in reflected sunlight and solar absorption. Through selective variations of the thin-film thicknesses and structures, nature has used multilayer structures for a variety of purposes. In butterflies, the thin films result in a colorful iridescence that is used for signaling, courting, camouflage, and display. Moreover, these thin films appear to be multifunctional; the light not reflected is absorbed for thermoregulation purposes. Variations of thin films in butterfly scales of different species results in different spectral and total reflectivity characteristics. An experimental apparatus was used to measure the spectral reflectivity from single scales, ∼100 μm long. Images of the illuminated scales reveal the effect of the microstructure on the optical properties.
Mass Transport Considerations for Micro-Gravity Cell Cultures in the NASA/JSC Bioreactor
Authors: Kleis Stanley J. , Begley Cynthia M.
Published: September 2024

The current NASA/JSC rotating wall perfused bioreactor vessel was developed to provide an environment for the culture of mammalian cells with a controllable and low level of mechanical stress. The accurate prediction of the transport of the nutrients and oxygen to the cells requires a detailed knowledge of the flow field, the concentration distributions of various quantities within the fluid phase, and the motion of the microcarriers with cells relative to the fluid phase. Computed velocity fields were used to numerically solve for the transient scalar concentration distributions of oxygen within the vessel. Oxygen was chosen as the representative scalar to study because of the relatively high cell requirements for oxygen and the low solubility of oxygen in the fluid medium. Results of the numerical simulations show that the strong secondary flow, driven by the viscous pump, produces rapid distribution of inlet concentrations which reduce concentration differences within the vessel while keeping the concentration difference between the inlet and outlet relatively high.

The trajectories of cells on microcarriers for different operating conditions were predicted for operation under micro-gravity conditions. The lack of gravity causes the slightly more dense cells and microcarriers to move under the influence of the pressure gradient, viscous shear, and centripetal acceleration fields. Results from the numerical solution of the resulting equations are compared with data from flight experiments flown on STS-70 in July, 1995.
Mass Transfer Characteristics of NASA Bioreactors by Numerical Simulation
Authors: Tsao Yow-Min D. , Gonda Steve R. , Pellis Neal R.
Published: September 2024

In this study, two bioreactors, each consisting of two concentric independently rotating cylinders, were evaluated by using computational fluid dynamics. The relative motion between the culture fluid (125 ml in the low aspect bioreactor and 250 ml in the high aspect bioreactor) and particles (150–3,000 micron diameter) was generated by a secondary flow resulting from different rotation rates of the two concentric cylinders. This study included computation of flow fields, perfusion effects, particle trajectories, shear forces and Sherwood number. Results indicate that the larger particles were suspended close to the end caps of the bioreactor, and smaller particles followed the streamline of the secondary flow and were distributed across the reactor vessel. Media perfusion at 5–20 ml/min had little effect on the overall flow field of the bioreactor, because the location of the inlet/exit perfusion ports short-circuited the extent of perfusion flow across the bioreactor. The aspect ratio of the vessel played an important role in the generation of secondary flow. The larger aspect ratio vessel required both a larger differential and faster rates of rotation to keep particles suspended. Particles located near the end caps in both vessels were subjected to higher forces. The force on the particles in the 125 ml vessel was half that on the particles in the 250 ml vessel. The Sherwood number indicated that the best mass-transfer conditions were present for larger particles in the larger aspect ratio vessel. In summary, maximizing the performance of a bioreactor in space requires minimizing the shear force generated by fluid flow, yet the flow movement must be enough to transfer nutrients. The results from this study indicate that four factors are crucial in this regard: (1) a uniform flow field, (2) a low aspect ratio vessel, (3) a well designed perfusion loop and (4) sufficient nutrient transfer to support cell growth.
Development of Closed Systems for Ex Vivo Cell Processing: Utility in Cell and Gene Therapy
Authors: Hardwick R. Alan , Levine Bruce L. , June Carl H. , Cotte Julio , Malech Harry L. , Butz Robert E. , Carter Charles S. , Maples Phillip B.
Published: September 2024

Two examples are described in which cells were processed in a closed sterile fluid path by using custom-designed instruments, plastic bags and tubing sets, and a sterile connection device. In the first example, nucleated blood cells were collected from HIV+ patients. These cells were enriched for CD4+ cells and the CD4+ cells were expanded in the presence of immobilized CD3 and CD28 antibodies. The cells were then concentrated, washed, and re-infused. For the largest batches this resulted in 2.20 × 1010 cells with 86% viability and a CD4+ cell purity ≥ 95%. In two out of three re-infused patients, CD4+ cell counts have remained elevated. In the second example, nucleated blood cells were collected from chronic granulomatous disease (CGD) pauents. CD34+ progenitor cells were immunomagnetically selected and then transfected with a retrovirus containing a corrected copy of the p47 gene. This resulted in 10%–30% of the CD34+ cells being successfully transduced. After transduction, the cells were washed and re-infused. Corrected neutrophils were transiently detected in all five patients. The closed system approach to cell processing is particularly well-suited to clinical trials in cell therapy and gene therapy.
Hematopoietic Stem Cell Engineering: The Magic Bullet of the Next Millenium?
Authors: Gee A. P.
Published: September 2024

Hematopoietic stem cell [HSC] therapy has its origins as hematological rescue following marrow ablative high-dose therapy for refractory cancers and myelodysplastic syndromes. In its simplest form, bone marrow is collected from a tissue-matched related normal donor and intravenously infused into the patient who has usually received high-dose chemo/radiotherapy for his or her disease. The stem cells migrate to the marrow spaces, where they multiply and differentiate to restore blood cell-forming activity and immune defenses in the recipient Restrictions in the availability of tissue-matched marrow donors have prompted investigations into new sources of stem cells. These include use of the autologous marrow, which is collected from the patient and cryopreserved prior to therapy. The risk of tumor contamination in these grafts has resulted in the development of numerous methods to purge cancer cells from marrow ex vivo, or to enrich stem cells from the graft. This provided one of the earliest clinical applications for monoclonal antibodies and immunomagnetic cell separation. Another approach has been to use tissue-matched unrelated volunteer marrow donors, or grafts from mismatched family members. In both cases, ex vivo removal of T lymphocytes from the graft is advisable to prevent these cells initiating a severe or fatal reaction in the recipient - graft-versus-host disease. Recent studies have shown that recombinant human growth factors can be used to stimulate migration of HSC from the marrow into the blood, from which they are collected by automated cell separators, obviating the need for harvesting marrow under general anesthesia. The same growth factors have been used to expand and differentiate HSC ex vivo, with the hope that clinical grafts could ultimately be grown in the laboratory from a few milliliters of blood or marrow. Transplants have also been performed using placental/umbilical cord blood as the HSC source, and there are some indications that these cells may be more suitable for mismatched transplants. Genetic manipulation of stem cells can be used to correct a number of inherited diseases, and ultimately may allow specific beneficial properties to be introduced into blood-derived cells e.g. drug resistance into stem cells - to allow higher doses of chemotherapy to be used without destroying the bone marrow. The rapid expansion in this field of medicine, combined with advances in molecular and cellular biology offer the promise of stem cell engineering as an effective therapy in a variety of diseases.
Cryopreservation of Cultured Blood Cells for Use in Gene Therapy and Immunotherapy
Authors: Hubel Allison , McCullough Jeffrey
Published: September 2024

The freezing characteristics of genetically manipulated lymphocytes and hematopoietic stem cells were studied. The water transport characteristics of stem cells which had been cultured and transduced with a therapeutic gene were different from that of a freshly isolated cells. Changes in the freezing characteristics for genetically transformed lymphocytes were also observed. Specifically, cryopreservation protocols developed for the fresh peripheral blood lymphocytes do not produce comparable survival rates for lymphocytes which have been cultured and transduced. These results indicate that there are significant changes in the freezing characteristics resulting from the culture and transduction process.
Biothermal Engineering: Present Status, Future Directions
Authors: Chato John C.
Published: September 2024

Biothermal engineering is an interdisciplinary field in which it is extremely important that the researchers in the two major complimentary disciplines, engineering and biology (including medicine), keep in touch with each other. Contact and exchange of ideas within the same discipline is effectively accomplished in conferences and meetings of the various professional societies. Reaching across disciplines, however, is a much more difficult task and requires special effort. Although many research groups have established fruitful cooperative efforts among the various disciplines for the performance of specific tasks, it is of great importance and benefit to bring together a larger group of workers from engineering, biology, and medicine to examine a field from an overall viewpoint and to identify promising new avenues for future work.
Modeling of Human Thermal Regulation for Liquid Cooling Garment Applications
Authors: Nyberg Karen L. , Diller Kenneth R. , Wissler Eugene H.
Published: September 2024

The Wissler Human Thermoregulation Model has been adapted for use in the design of control schemes for regulating liquid cooling garment (LCG) inlet coolant temperature. The model was used to simulate various activity scenarios in a space suit while both liquid coolant and ventilation gas were in thermal communication with the human subject. Model parameters were identified which best represent the actual LCG system currently used by NASA. Simulations were performed for the metabolic and thermal activity histories of two different sets of test data available from the Johnson Space Center (JSC). It was demonstrated that the modified Wissler model, incorporating the LCG and ventilation flow effects, simulates actual human thermal and metabolic responses over a broad range of transient work loads and can therefore be reliably applied for design of a future automated thermal control scheme.
A Model of Cryosurgical Destruction in AT-1 Prostate Tumor Based on Cellular Damage Mechanisms
Authors: Smith David J. , Josephson Sean J. , Bischof John C.
Published: September 2024

The thermal history during a prostate cryosurgery is known to lead to different cooling rates, end-temperatures and end-times within a cryosurgical iceball. The tissue exposed to this range of thermal histories will experience thermally-induced biophysical events which affect cell viability (dehydration and intracellular ice formation. IIF), injury due solely to the temperature and time of exposure, and injury due to host response. In this study, the dehydration and IIF behavior of single AT-1 prostate cancer cells is experimentally measured, the biophysical parameters of water transport and IIF are obtained, and the probability of injury to single AT-1 cells due to dehydration (Prd) and IIF (PIF) is predicted for a variety of cryosurgically-relevant thermal histories. In addition, viability data obtained after cooling to different end-temperatures at constant coolins rates is used to create an empirical function of injury for single AT-1 cells based solely on end-temperature (Pre). A total cellular injury model which then combines the biophysical mechanisms of injury as well as the empirically-obtained temperature viability function is created. This model is used to predict worst-case (i.e. highest possible survival) cryosurgical destruction in an AT-1 tumor; the implications for clinical cryosurgery are discussed.
Poloxamer 188 Enhances Functional Recovery of Lethally Heat Shocked Fibroblasts
Authors: Merchant Fatima , Holmes William , Toner Mehmet
Published: September 2024

Surfactant molecules, specifically triblock polymers such as Poloxamer 188 (P-188) have been shown to restore cell membrane integrity. The objective of this study was to develop functional and morphological assays to determine whether treatment with P-188 after heat shock enhances the recovery of lethally damaged cells. Human foreskin fibroblasts (HFF) were heated in suspension and cell recovery after heat shock was assessed using a functional assay based on the contraction of fibroblasts populated collagen lattices (FPCLs). Experiments were performed to evaluate the effect of various concentrations of P-188 on cell recovery after heat shock, and to determine the influence of P-188 on cells subjected to varying degrees of heat stress. Further, the cytoskeletal morphology was determined via confocal microscopy of the fluorescently labeled (Rhodamine Phalloidan) filamentous actin network. Our results indicate that treatment with low concentrations of P-188 after heat shock is effective in ameliorating both the morphological integrity and contractile function of cells for a threshold of thermal stress (45°C for 20–60 minutes). The beneficial influence of P-188 on heat shocked cells coupled with the applicability of FPCL as a reasonable in vitro model for wound healing make these results promising for clinical application.
Theoretical Study of the Temperature Fluctuations Induced During Reflected-Scanned Planar Ultrasound Hyperthermia
Authors: Moros Eduardo G. , Fan Xiaobing , Straube William L.
Published: September 2024

Temperature fluctuations inside of a target volume during scanned planar ultrasound hyperthermia were investigated numerically by varying scan time, blood perfusion, and skin temperature. Three dimensional (3-D), transient, acoustic power deposition patterns induced by a scanning ultrasound reflector linear array system (SURLAS) were simulated and input into an homogeneous, 3-D, transient, bioheat transfer equation model. It was found that the largest temperature fluctuations were located at the ends of the linear scan path where the scanning reflector comes to a sudden stop and reverses direction. The smallest fluctuation was located at the center of the scan window. For a given scan distance, the magnitude of the temperature fluctuations increased linearly with increasing scan time, and increased as a weak exponential function of blood perfusion rate. A scan time of 20 s or less is necessary to keep the temperature fluctuations within ±0.5 °C from the average temperature in a scan cycle for a scan window of 10 × 10 cm and a blood perfusion rate of 5 kg/m3s.
Near Infra Red Spectroscopy of Biological Tissues
Authors: Jones Matthew R. , Yamada Yukio
Published: September 2024

The development of spectroscopic techniques plays a key role in many newly emerging diagnostic and theraputic applications of near infra red (NIR) radiation in medicine. In applications such as photodynamic therapy, optical tomography and laser surgery it is necessary to know the optical properties of various types of biological tissue in order to predict how light will propagate and be distributed throughout the body. The optical parameters of primary interest are the reduced scattering coefficient and the absorption coefficient. In this paper, we discuss the use of the diffusion approximation as a model of the light propagation in biological tissues. We also describe one possible spectroscopic method which uses spatially resolved, transient reflectance measurements to determine the optical properties of biological tissues.
Three-Dimensional Finite Element Analysis of Stress Response in Adhesive Butt Joints Subjected to Impact Bending Moments
Authors: Sawa Toshiyuki , Okuno Hirohisa , Higuchi Izumi , Kato Shinya
Published: September 2024

The stress wave propagation and the stress distribution in adhesive butt joints of T-shape similar adherends subjected to impact bending moments are analyzed using three-dimensional finite-element method (FEM). An impact load is applied to a joint by dropping a weight. FEM code employed is DYNA3D. The effects of Young’s modulus of adherends, the adhesive thickness and the web length of T-shape adherends on the stress wave propagation at the interfaces are examined. It is found that the maximum stress occurs at the interfaces. In the case of T-shape adherends, it is seen that the maximum principal stress at the interfaces increases as Young’s modulus of the adherends increases. In the special case where the web length of T-shape adherends equals to the flange length, the maximum principal stress at the interfaces increases as Young’s modulus of the adherends decreases. The maximum principal stress at the interfaces increases as the adherend thickness decreases. In addition, strain response of adhesive butt joints was measured using strain gauges. Fairly good agreement is seen between the analytical and the experimental results.
Stress Analysis and Strength of Adhesive Lap Joints of Dissimilar Hollow Shafts Subjected to Axial Load
Authors: Nakano Yuichi , Kawawaki Masataka , Sawa Toshiyuki
Published: September 2024

The stress and strain distributions in adhesive lap joints of dissimilar hollow shafts subjected to an axial load are examined using an axisymmetric theory of elasticity. The effects of the ratio of Young’s modulus of the adhesive to that of the shaft and of the thickness of the adhesive on the stress distributions at the interfaces in the joint are clarified numerically. It is seen that the stresses in radial and circumferential directions become singular at the ends of the interfaces and the stress increases near the ends of the interface with a decrease of Young’s modulus of the shaft and with an increase of the thickness of the adhesive. For verification of the stress analysis, the strain distribution at an outer surface of the adhesive lap joint was measured and a fairly good agreement was shown by comparing the experimental results with the analytical predictions. Moreover, the tensile strength of adhesive lap joints was measured and evaluated by stress analysis.
Rotating-Loosening-Free Conditions of Joint Structure That Fastens Drive-Shaft and Hub in Automobile Axle
Authors: Sakai Tomotsugu
Published: September 2024

In many automobiles, to prevent the nut loosening, the fastening structure of drive-shaft and hub in their axles has the lock-nut and the shaft with lead angled spline teeth to get the tight pressed-in fit, or very precisely machined/rolled spline teeth to eliminate the circumferential clearance. But, in these structures, the production process both of machining/rolling spline and of assembling the shaft and the hub becomes more complicated. So, more attention must be paid to the production process. As a result, the production cost and time can not help being higher and longer. Therefore, the author analyzed the necessary conditions that prevent the rotating loosening of the nut even without the above-mentioned spline, and got five independent necessary conditions that consist of the joint specifications.

➀ TF > TE, TE: the drive line transmitted torque, TF: the friction torque between the shaft and the hub. ➁ θcr > θ, θ: the relative rotating angle between the shaft and the hub under the torque TE, θcr: the “rotating-loosening-free critical angle” of the fastening axis. ➂ | deμs / dw cos α − μw | > P / π dw, de: effective diameter of thread, dw: equivalent diameter of bearing surface, α: half angle of thread, P: pitch of thread, μs: friction coefficient of thread surface, μw: friction coefficient of bearing surface. ➃ TsLOCK > Tw − TsL, TsLOCK: thread surface locking torque. ➄ TwLOCK > TsT − Tw, TwLOCK: bearing surface locking torque. Here, Tw: friction torque on bearing surface, TsL: releasing torque on thread surface, TsT: tightening torque on thread surface.

If at least one of these five conditions is satisfied, the screw thread can not loosen by rotating.
On the Reliability Analysis of VLSI Chips When Subjected to Thermal Cycling
Authors: Jahanian Shahriar , Goshtasbi-G Jamshid
Published: September 2024

Elevated temperature has been considered as a dominant factor of stress which lowers the reliability and life expectancy of the microelectronics devices. Arrhenius model is commonly used for predicting the reliability and failure rate of the microelectronics devices as a function of ambient temperature. Arrhenuis model extrapolates life data, obtained from units tested at constant elevated temperatures, to the working temperatures. Generally, the temperature of microelectronics devices are lowered using an appropriate cooling method to achieve a desired reliability and life expectancy. However, during the cooling process the chips are subjected to transient temperature change that enhances the chance of fracture and eventually failure of chips.

Cyclic thermal stresses are the common cause of the fracture of mechanical structures. Accordingly, when cooling microelectronics devices, the following questions are raised;

• Considering the possibility of the fracture of microelectronics devices when subjected to cyclic thermal loading, how does this effect in life expectancy and reliability of chips (by lowering the temperature) as predicted by Arrhenius model.

• Considering the cost of lowering the temperature of these devices, could there be an optimal temperature yielding an acceptable reliability and life expectancy with lower cooling cost?

This problem in particular becomes more critical in case of (Very Large Scale - Integration) VLSI chips, where highly dense circuits occupy almost all area of the die. Hence the probability of failure due to fracture in VLSI chips is highly expected. For this case a different model than Arhenuis model is needed to correctly predict the reliability and life expectancy of VLSI chips when subjected to thermal cycling. This paper presents a methodology for developing such a model that include the possibility of the fracture of VLSI chips subjected to cyclic thermal loading.
Pharmacologic evaluation of delayed long-acting cabotegravir administration among cisgender women in HPTN 084
Authors: Marzinke Mark A. , Han Kelong , Hanscom Brett , Guo Xu , Piwowar-Manning Estelle , Hendrix Craig W. , Rose Scott , Spooner Elizabeth , Mathew Carrie , Innes Steven , Sekabira Rogers , Mutambanengwe Mercy , Rooney James F. , Rinehart Alex R. , Adeyeye Adeola , Cohen Myron S. , Hosseinipour Mina , Ford Susan L. , Delany-Moretlwe Sinead
Published: September 2024

HPTN 084 demonstrated the superiority of long-acting injectable cabotegravir (CAB-LA) compared with daily oral tenofovir disoproxil fumarate–emtricitabine (F/TDF) for HIV prevention in women. CAB-LA (600 mg) or placebo injections were administered 4 weeks after an initial dose (loading dose) and every 2 months (Q2M) thereafter; this is the approved regimen. Participants experienced both loading dose and Q2M delays during the trial. CAB concentrations were evaluated before a delay, at the visit associated with the delay, and the visit after a delayed injection was administered. During the blinded phase of the trial, 194 participants randomized to CAB-LA experienced at least one injection delay. Plasma CAB concentrations were maintained above the 4× protein adjusted 90% inhibitory concentration (4× PA-IC
90
; protocol-specific threshold) for all loading dose and 98% of Q2M delays when injections were administered up to 6 weeks late. The feasibility of shifting to an every 3-month (Q3M) regimen in females was interrogated via simulation studies using a population pharmacokinetic model. Q3M injections in both CAB-naïve (with a loading dose) and previously CAB-exposed females were predicted to yield higher steady-state exposures than in males on the approved Q2M regimen. Although there is observed forgiveness following an isolated delayed CAB-LA injection and simulations suggest acceptable CAB-LA exposures in women with a 600 mg CAB-LA Q3M regimen, empirical efficacy of this regimen has not been established, and transitioning to this dosing schema is not recommended. Future pharmacokinetic bridging studies are aimed at evaluating higher dose CAB-LA formulations administered less frequently.

CLINICAL TRIALS

This study is registered with

ClinicalTrials.gov
as
NCT03164564

.
Integrating short- and full-length 16S rRNA gene sequencing to elucidate microbiome profiles in Pacific white shrimp (
Litopenaeus vannamei
) ponds
Authors: Rajonhson Dora M. , Angthong Pacharaporn , Thepsuwan Timpika , Sutheeworapong Sawannee , Satanwat Penpicha , Tapaneeyaworawong Paveena , Powtongsook Sorawit , Kruasuwan Worarat , Jenjaroenpun Piroon , Wongsurawat Thidathip , Chaiyapechara Sage , Rungrassamee Wanilada
Published: September 2024

Despite their immense economic value as a key aquaculture species, the production of Pacific white shrimp (
Litopenaeus vannamei
) faces significant challenges from intensive farming practices and disease outbreaks. Routine microbial profiling for disease surveillance could be a promising approach to anticipate and control disease outbreaks. To achieve this, accuracy in microbial profiling in shrimp ponds is crucial for enabling targeted action and prevention. Extensive documentation emphasizes that, beyond biological factors (related to the host, diet, or health status during the rearing period), technical elements, including sequencing techniques significantly influence bacterial community profiling. This study investigated the influence of short- and long-read sequencing of 16S rRNA genes on the microbial profiles in shrimp intestines, water, and sediments. The origin of the samples (intestine or environmental) in shrimp culture ponds primarily drove the observed differences in core microbial species. The ecological niches accounted for 56% of bacterial community variations in culture ponds. Both sequencing approaches showed consistent results in identifying higher-rank taxa and assessing alpha and beta diversity. However, at the species level, full-length 16S rRNA gene sequences provided better resolution than V3–V4 sequences. For routine microbial profiling in shrimp culture ponds, our study suggests that short-read sequences were sufficient for determining overall bacterial community.

IMPORTANCE

This interdisciplinary study investigated the influence of sequencing techniques on bacterial communities profiling within Pacific white shrimp (
Litopenaeus vannamei
) ponds. By integrating aquaculture, microbiology, and environmental science, we revealed the role of ecological niches and factors like salinity and pH on microbiota diversity and composition in shrimp intestines, pond water, and sediment. Additionally, we compared the taxonomic resolution using partial versus full-length 16S rRNA gene sequences, highlighting the value of longer amplicons for precise identification of key taxa. These findings provide novel insights into microbial dynamics underlying environmental effects in shrimp aquaculture. Comprehensive characterization of the pond microbiome could lead to management strategies that promote shrimp health and productivity. Furthermore, the potential of a multi-omics approach for integrating complementary data streams to elucidate environment-microbiome-host interactions was highlighted.
Effects of photobiomodulation therapy associated with motor control exercise for chronic non-specific low back pain: protocol for a randomised placebo-controlled trial
Authors: de Oliveira Marcelo Ferreira Duarte , Bjordal Jan Magnus , Schardong Jociane , Plentz Rodrigo Della Méa , Casalechi Heliodora Leão , Leal-Junior Ernesto Cesar Pinto , Tomazoni Shaiane Silva
Published: September 2024

Photobiomodulation therapy (PBMT), as an adjunct therapy to exercise, can reduce pain in musculoskeletal disorders. In addition, PBMT associated with exercise decreases fatigue, accelerates muscle recovery and enhances performance and gain through different training protocols. Although it has not been investigated, the association of PBMT and exercise therapy could be an alternative to improve the positive effects of exercise in patients with non-specific low back pain (LBP). Therefore, we aim to evaluate the effects of PBMT associated with motor control exercise (MCE) versus placebo associated with MCE in patients with chronic non-specific LBP. This is a prospectively registered, two-arm, randomised, placebo-controlled, triple-blind trial. A total of 148 patients with chronic non-specific LBP will be randomised to either active PBMT associated with MCE or placebo PBMT associated with MCE. Treatment sessions will be provided twice a week for 6 weeks. The primary outcomes will be pain intensity and general disability measured at the end of the treatment. The secondary outcomes will be pain intensity and general disability measured 1 month after the end of the treatment, 3, 6 and 12 months after randomisation, in addition to levels of prostaglandin E2 measured at the end of the treatment. Medication intake, cointerventions and adverse events will be measured at all time points. This study was approved by the Research Ethics Committee of Irmandade de Santa Casa de Misericórdia de Porto Alegre. The results will be disseminated through scientific publications and presentations at scientific meetings.

Trial registration number:
NCT05487118
.
Randomised, double-blind, multicentre, mixed-methods, dose-escalation feasibility trial of mirtazapine for better treatment of severe breathlessness in advanced lung disease (BETTER-B feasibility)
Authors: Higginson Irene J , Wilcock Andrew , Johnson Miriam J , Bajwah Sabrina , Lovell Natasha , Yi Deokhee , Hart Simon P , Crosby Vincent , Poad Heather , Currow David , Best Emma , Brown Sarah
Published: September 2024

New treatments are required for severe breathlessness in advanced disease. We conducted a randomised feasibility trial of mirtazapine over 28 days in adults with a modified medical research council breathlessness scale score ≥3. Sixty-four patients were randomised (409 screened), achieving our primary feasibility endpoint of recruitment. Most patients had COPD or interstitial lung disease; 52 (81%) completed the trial. There were no differences between placebo and mirtazapine in tolerability or safety, and blinding was maintained. Worst breathlessness ratings at day 28 (primary clinical activity endpoint) were, 7.1 (SD 2.3, placebo) and 6.3 (SD 1.8, mirtazapine). A phase III trial of mirtazapine is indicated. Trial registration:32236160; European Clinical Trials Database (EudraCT no: 2015-004064-11).
Ultrasonic interrogation of a clayey tailings during sedimentation–consolidation
Authors: Peruga Hirlatu , Khanlarian Misagh , Cascante Giovanni , Simms Paul
Published: September 2024

Ultrasonic methods are used for non-destructive detection of changes of low-strain properties in concrete, soils, and other materials. This paper presents the use of ultrasonics to detect density and structure changes in a soft clayey tailings. Such tailings undergo sedimentation and consolidation following their deposition, which may occur simultaneously with flocculation and other fabric-altering processes, resulting in time-dependent consolidation characteristics. Here we attempt to measure structural changes in the clayey tailings using ultrasonics, which presents several challenges due to the material’s relative softness. Ultrasonics testing was attempted using a special 3D printed column with height and diameter of 540 and 110 mm, respectively. Specially fabricated sample holders were designed to repeatedly ensure proper connections of compression (P-wave) and shear (S-wave) wave transducers. The arrival time corresponding to the largest P-wave amplitude showed a strong correlation with density of the tailings, while a specific frequency bandwidth of the P-wave spectra indicates an increase in wave amplitude (signal energy) occurring subsequent to most of the volume change. Ultrasonic measurements appear to be a promising technique to monitor density and stiffness in soft clays, tailings, and similar soft sediments.
Hydraulic conductivity of air-dried bentonite–sand blocks permeated with synthetic groundwater from radioactive waste repository
Authors: Zhou Guangping , Tan Yu , Peng Yu , Zhang Huyuan , Zhang Poyu , Chen Jiannan , Liu Ping
Published: September 2024

Laboratory experiments were conducted to evaluate the impact of drying cracks on hydraulic conductivity of compacted bentonite–sand blocks used as engineered barriers for radioactive waste disposal. Blocks were air-dried in an indoor environment to simulate the worst scenario without protection from drying during the interim storage and installation of the block. Synthetic groundwaters around the promising repository area were used as permeant solutions to study the hydraulic conductivity of air-dried blocks. Air-dried block samples were scanned by computed tomography (CT) before and after permeation to visualize the healing of drying cracks. Results show that swelling of the blocks was suppressed by the chemical components in the synthetic groundwater, and hydraulic conductivity of the block increased slightly (<4×) when permeated with the synthetic groundwater than those permeated with deionized water. Hydraulic conductivity of the air-dried block with cracks was slightly higher (<3×) than the hydraulic conductivity of the fresh block without cracks, indicating the remained swelling of the block permeated with synthetic groundwaters is sufficient to heal drying cracks. The healing of drying cracks was also quantified by CT images. These findings can increase the tolerance of drying cracks during block storage and installation.
New charged anisotropic solution in f(Q)-gravity and effect of non-metricity and electric charge parameters on constraining maximum mass of self-gravitating objects
Authors: Maurya S. K. , Ashraf Asifa , Al Khayari Fadhila , Mustafa G. , Jasim M. K.
Published: September 2024

In the present article, A new class of singularity-free charged anisotropic stars is derived in f(Q)-gravity regime. To solve the field equations, we assume a particular form of anisotropy along with an electric field and obtain a new exact solution in f(Q)-gravity. The explicit mathematical expression for the model parameters is derived by the smooth joining of the obtained solutions with the exterior Reissner–Nordstrom de-Sitter solution across the bounding surface of a compact star along with the requirement that the radial pressure vanishes at the boundary. We have modeled four self-gravitating pulsar objects such as LMC X-4, PSR J1903+327, PSR J1614-2230, and GW190814 in our current study and predict the radii of these objects that fall between 8 and 10 km. Furthermore, the physical validity of the solution is performed for self-gravitating object PSR J1614-2230 with mass $$1.97\pm 0.04~M_{\odot }$$

1.97
±
0.04

M
⊙

with radius 10 km. The solution successfully fulfills all the physical requirements along with the stability and hydrostatic equilibrium conditions for a well-behaved model. The non-metricity f(Q)-parameter $$\chi _{_1}$$

χ

1

and electric charge parameter $$\eta $$
η
play an important role in the maximum mass of the objects. The maximum mass increases when $$\chi _{_1}$$

χ

1

and $$\eta $$
η
increase but a non-collapsing stable object can be obtained when $$\chi _{_1}\le 0.0205$$

χ

1

≤
0.0205

and $$\eta \le 0.0006$$

η
≤
0.0006

.
Quasinormal modes, thermodynamics and shadow of black holes in Hu–Sawicki $$\varvec{f(R)}$$ gravity theory
Authors: Karmakar Ronit , Goswami Umananda Dev
Published: September 2024

We derive novel black hole solutions in a modified gravity theory, namely the Hu–Sawicki model of f(R) gravity. After obtaining the black hole solution, we study the horizon radius of the black hole from the metric and then analyse the dependence of the model parameters on the horizon. We then use the 6th order WKB method to study the quasinormal modes of oscillations (QNMs) of the black hole perturbed by a scalar field. The dependence of the amplitude and damping part of the QNMs are analysed with respect to variations in model parameters and the error associated with the QNMs are also computed. After that we study some thermodynamic properties associated with the black hole such as its thermodynamic temperature as well as greybody factors. It is found that the black hole has the possibility of showcasing negative temperatures and is thermodynamically unstable for feasible values of model parameters. Then we analyse the geodesics and derive the photon sphere radius as well as the shadow radius of the black hole. The photon radius is independent of the model parameters while shadow radius showed fair amount of dependence on the model parameters. We tried to constrain the parameters with the help of Keck and VLTI observational data and obtained some bounds on m and $$c_{2}$$

c
2

parameters.
BAYESIAN ESTIMATION OF A DSGE MODEL WITH INVESTMENT-SPECIFIC TECHNOLOGY SHOCKS: THE CASE OF BANGLADESH
Authors: Islam Saidul
Published: September 2024

This paper builds a real business cycle (RBC) model to identify the transitory and permanent components of neutral and investment-specific technology (IST) shocks. This paper applies the Bayesian estimation method to discern IST shocks’ contribution to Bangladesh’s business cycle fluctuations. The variance decomposition results indicate that the model attributes most of the aggregate fluctuations to the permanent components of both technology shocks. Further, the model satisfactorily generates a counter-cyclical trade balance-to-output ratio consistent with data. However, it fails to replicate the excess relative consumption volatility and a downward-slopping autocorrelation function (ACF) of the trade balance-to-output ratio. Introducing a consumption external habit addresses the model’s inadequacies to a certain extent. An alternative preference specification, Jaimovich–Rebelo remarkably improves the model’s performance along the second-moment statistics while maintaining the contributions of technology shocks at the same level.
LEVERAGING CORPUS LINGUISTICS AND DATA-DRIVEN DEEP LEARNING FOR TEXTUAL EMOTION ANALYSIS
Authors: ASKLANY SOMIA A. , AL-SHATHRY NAJLA I. , HASSAN ABDULKHALEQ Q. A. , AL-DOBAIAN ABDULLAH SAAD , ALMANEA MANAR , ALGHAMDI AYMAN AHMAD , SADIG MUTASIM AL
Published: September 2024

Emotions have played a major part in the conversation, as they express context to the conversation. Text or words in conversation contain contextual and lexical meanings. In recent times, obtaining emotion from the text has been an attractive area of research. With the emergence of machine learning (ML) algorithms and hardware to aid the ML method, identifying emotion from the text with ML provides significant and promising solutions. The main objective of Textual Emotion Analysis (TEA) is to analyze and extract the user’s emotional states in the text. Many different Complex Systems and Deep Learning (DL) algorithms have been fast-paced developed and proved their effectiveness in several fields including audio, image, and natural language processing (NLP). This has moved researchers away from the classical ML to DL for their academic research work. This study develops a new Corpus Linguistics and Data-Driven Deep Learning for Textual Emotion Analysis (CLD3L-TEA) technique. The CLD3L-TEA technique mainly investigates the distinct types of emotions that endure in the social media text. In the CLD3L-TEA model, the raw data can be pre-processed in distinct ways. Next, a multi-weighted TF–IDF model is used to generate feature vectors. For the identification of emotions, the CLD3L-TEA technique applied a gated recurrent unit (GRU). At last, the hyperparameter range of the GRU model is executed by the Fractal Harris Hawks Optimization (HHO) model. The experimental validation of the CLD3L-TEA technique on a benchmark dataset illustrates the supremacy of this technique over recent approaches.