bluuebunny/crossref_metadata_2025_split huggingface dataset:
Establishment of mouse models for severe pulmonary hypertension through ‘double‐hit’ strategies
Authors: Chen Lingdan , Chen Xin , Huang Yuhang , Ma Zhuoji , Zeng Xiaohui , Wang Tao 
Published: September 2024

AbstractMouse models are crucial for understanding pulmonary hypertension (PH) mechanisms and developing therapies, but existing mouse models under hypoxia only exhibit mild PH. To address this, we established a double‐hit model combining unilateral pneumonectomy (LPx) or left pulmonary artery ligation (LPAL) with hypoxia exposure in C57BL/6 mice. Our detailed haemodynamic and histological evaluations post‐surgery demonstrated pronounced elevations in right ventricular systolic pressure (RVSP) (LPAL: 41.1 ± 4.63 mmHg, P = 0.005; LPx: 38.4 ± 2.95 mmHg, P = 0.002; Sham: 32.1 ± 2.21 mmHg) and pulmonary vascular wall thickness (LPAL: 56.9 ± 3.34%, P = 0.02; LPx: 54.3 ± 4.65%, P = 0.04; Sham: 44.8 ± 3.76%) compared to hypoxia‐exposed sham‐operated controls, reflecting a more severe PH phenotype. These novel models, which exhibit haemodynamic alterations akin to the established hypoxia with SU5416‐induced PH model as per published data, could offer a substantial contribution to future PH research and therapeutic development.
Experimental Application of a Method for Hidden Parameter Tracking in a Slowly Changing, Chaotic System
Authors: Cusumano J. P. , Chelidze D. , Chatterjee A. 
Published: September 2024

Abstract
Results are presented of an experimental application of a method for tracking hidden parameters in slowly changing chaotic systems. The method exploits the time scale separation between fast dynamic variables and a slow drifting parameter. Locally linear tracking models are constructed using data from the reference system sampled on a fast time scale, employing delay coordinate embedding. These reference models are used to track parameter drift. The method is successfully applied to a forced oscillator with a two-well potential. The effect of the choice of prediction time interval is studied. It is also observed that a simple correction for estimated modeling error gives a more sensitive tracking metric. For purposes of comparison with such model-based tracking methods, a heuristic method is also presented for detecting parameter changes using the autocorrelation function of the recorded time series. The relative merits of heuristic versus model-based techniques are discussed. Directions for future work are suggested.
Bubble Elimination Device in Hydraulic Systems
Authors: Suzuki Ryushi , Tanaka Yutaka , Yokota Shinichi 
Published: September 2024

Abstract
Bubbles in working fluids have much influence on the performance of hydraulic systems and cause some troubles. In this paper, the performance of the developed bubble elimination device concerning the effect of reducing the oil temperature rise is experimentally investigated. From a view point of energy balance in hydraulic systems, a simple mathematical model is proposed and validity of the model is studied.
On the Stability and Performance of Two-Stage Hydraulic Servovalves
Authors: Wright Heather , Alleyne Andrew , Liu Rui 
Published: September 2024

Abstract
In this work, a System Dynamics viewpoint is used to examine the stability and performance of a class of hydraulic devices. These devices use hydraulic amplification to command motion of large objects using relatively low level signals. A model is constructed and used for both analysis and simulation of system performance. The analysis is from a linear Classical Controls perspective and is found to be sufficient despite the nonlinear nature of the systems. The analysis is used to consider design changes to the valve components and their resulting effects. Even though the subsystems consist of stable individual components, their interconnection can lead to undesirable performance, or even instability, if the individual dynamics are improperly matched.
Numerical Simulation of Global Diffusive Mass Transfer in a Rotating-Wall Vessel Bioreactor
Authors: Gao Hongxia , Ayyaswamy Portonovo S. , Ducheyne Paul 
Published: September 2024

Abstract
The global diffusive mass transfer of different chemical species, specifically nutrition (glucose) and oxygen, in the fluid cell culture medium of the NASA designed Rotating-Wall Vessel (RWV) bioreactor has been numerically investigated. A finite difference method was employed to solve the governing equations for the species mass fraction fields. We have considered the 55 ml STLV and the 50 ml HARV as our domains of interest. The cell metabolic processes have been modeled as mass sinks absorbing oxygen and nutrition in the culture medium with time-dependent strengths. In one case studied, relative motion between the microcarrier and the fluid culture medium has been taken into account. The transient two-dimensional analysis employed here simulates the global mass diffusion process in the RWV. For the parameters considered here, the numerical results indicate that the HARV may be a better bioreactor for oxygen transport compared to the STLV.
Experimental and Analytical Studies of Heat Removal by Regionally Controlled Liquid-Cooled Garments
Authors: Shitzer Avraham 
Published: September 2024

Abstract
Space exploration, and particularly extravehicular activities, require creation of a “micro-climate” for the removal of metabolic heat. This is accomplished by a specially designed thermal garment. The early garments used by NASA for the Gemini program were air-ventilated. These proved to be inadequate and were subsequently replaced by water-air hybrid garments for the Apollo program (Chambers, 1970). These garments were made of flexible plastic tubes attached to a loosely-knit fabric. Cooled water circulated in the tubes which were in contact with the skin. Additionally, conditioned air flew across the outer layer of the fabric thereby removing sweat secreted.
Thermal Wave Propagation in a Thin Membrane Subjected to an Exponentially Growing/Decaying Wall Temperature
Authors: Tan Zhi-Ming , Yang Wen-Jei 
Published: September 2024

Abstract
Propagation of thermal waves in transient heat conduction in a very thin membrane is investigated by solving hyperbolic heat conduction equation. Analytical expressions are obtained for the temperature and heat flux distributions. Numerical computations are performed in order to determine the behavior of temperature and heat flux distributions in transient heat conduction. It is disclosed that in transient heat conduction, a heat pulse propagates as a wave and quickly begins to attenuate in the membrane, the peak of thermal waves has a sharp increase when the wavefronts from two sides meet at the centre of the membrane and collide with each other the first time and has an obvious decrease the second time. The results show that non-Fourier heat conduction is extremely significant with certain range of membrane thickness and duration time, and Fourier’s law used in macroscale heat conduction cannot be applied. The results also show that both temperature overshoot and temperature undershoot would occur in the membranes with smaller values of x0/(τC) within a very short period of time. The ranges of membrane thickness and duration time within which heat propagates as a wave are also determined.
Experimental Studies of the Heat Exchange in Paired Vessels Using the Rat Spinotrapezius Muscle
Authors: Song Ji , Xu Lisa X. , Lemons Daniel E. , Weinbaum Sheldon 
Published: September 2024

Abstract
Research on blood-tissue heat transfer in the past twenty years has focused on the question of where and how vascular heat transfer occurs. A number of different bioheat transfer models have been developed [1,3,5] to explain the mechanism of blood-tissue energy exchange. Among them Weinbaum et al. proposed that nearly all thermally significant vessels in skeletal muscle appeared as closely spaced countercurrent pairs, and the primary mechanism by which the microvascular blood flow altered the blood tissue heat transfer was incomplete countercurrent exchange in the thermally significant microvessels [5]. An effective thermal conductivity, keff, which is related to the local vascular geometry and blood flow, was therefore introduced to account for the enhancement of heat transfer due to the thermally significant vessels [4]. The characteristic thermal equilibration length, Lei, plays an important role in revealing the mechanism of microvascular heat transfer. It is a key feature of thermally significant vessels, but this length has not yet been experimentally determined. A better understanding of microvascular countercurrent heat exchange requires experimental confirmation of the thermal equilibration and keff.
Temperature Responses in the Canine Prostate During Transurethral Microwave Hyperthermia
Authors: Zhu Liang , Xu Lisa X. , Holmes Ken R. 
Published: September 2024

Abstract
In this research, experiments were performed to study the thermoregulation in the canine prostate during microwave hyperthermia. The transurethral thermal therapy (T3) system provided by Urologix, Inc. was used to impose microwave heating in the canine prostate. Five types of temperature responses to different microwave power levels as time varies, including both damped and sustained oscillatory temperature responses, have been observed. The decrease in prostatic tissue temperature during the microwave heating is believed to be caused by the increase of local blood flow, which was stimulated by the tissue temperature elevation. This work will help to provide a better understanding of the mechanism of how the temperature regulates within the canine prostate during transurethral microwave hyperthermia.
Cryopreservation of Cells Using Ultra-Rapid Freezing
Authors: Fowler Alex J. , Toner Mehmet 
Published: September 2024

Abstract
This paper reports on the development of a new cryopreservation protocol that uses laser warming and liquid nitrogen cooling to establish extreme temperature gradients that lead to cooling rates of greater than 106 K per second. Experiments using short laser pulses demonstrate that these cooling rates lead to the creation of clear ice regions consistent with the creation of amorphous ice. Differential thermal analysis of the clear ice regions proves that they do consist of substantial portions of amorphous ice. It is believed that freezing cells in a non-crystalline ice will lead to successful cryopreservation of any cell type. Numerical simulations have allowed investigators to identify a geometry that will enable the freezing of cells and small tissue samples into an amorphous solid phase with the use of little or no cryoprotectant.
Perturbations of Large Vessels on Induced Temperature Distributions: Part A — Three-Dimensional Simulation Study
Authors: Craciunescu Oana , Clegg Scott T. 
Published: September 2024

Abstract
It is well known that large blood vessels perturb the induced temperature distributions in biological situations. The understanding of the magnitude of the perturbation of the temperature distribution as a function of the vessel size and temperature gradient are critical to the development of accurate (and useful) models of bioheat transport. Weinbaum et al. have demonstrated a method for measuring the temperature distribution due to the presence of “small vessels”. However, this technique is highly invasive and therefore not generally useful. An alternative to this method, is the use of a combination of MR image techniques to noninvasively measure 1) the location, size and velocity of certain blood vessels, and 2) the induced temperature distribution. This paper describes the principle of this method. Numerical simulations are to be used to evaluate the accuracy of the MR technique with particular emphasis on the perturbation around blood vessels. Prior to the evaluation of the accuracy of the MR technique, the accuracy of the numerical method must be determined. This paper reports on the numerical simulations performed for an inhomogeneous perfused phantom that resembles the phantom used in the experimental setup. The results agree with previously published data.
Stress Analysis of Bolted Joints Using Hexagon Bolts With Flanges and Estimation of Axial Bolt Load
Authors: Yasui Hajime , Sawa Toshiyuki , Motegi Youich 
Published: September 2024

Abstract
The contact stress distributions at the bearing surfaces between the bolt head with flange washer and clamped parts (hollow cylinder) are analyzed using axisymmetric theory of elasticity as a four-body contact problem. In the analysis, bolt head, flange washer and the bolt shaft are replaced with finite solid cylinders. In the numerical calculations, the effect of the dimensions of the flanges in hexagon bolts and the clamped parts (hollow cylinder) on the contact stress distributions are clarified. The contact stress distributions of bolted joints using hexagon bolts with flange washers are compared with those using hexagon bolts without flange washers. In addition, the equivalent length of the deformation in the bolt head with the flange is proposed in order to calculate the spring constant of bolt-nut system. Furthermore, a method for estimating an axial bolt force is proposed using the deformation of the bolt head. The deformations of bolt head in bolted joints using hexagon bolts with flange washers were measured with a surface roughness meter and the axial bolt load was measured with strain gauges. The estimated results are in fairly good agreement with the measured results.
Exogenous Glucose Oxidation During Exercise Is Positively Related to Body Size
Authors: Ijaz Abdullah , Collins Adam J. , Moreno-Cabañas Alfonso , Bradshaw Louise , Hutchins Katie , Betts James A. , Podlogar Tim , Wallis Gareth A. , Gonzalez Javier T. 
Published: September 2024

There is little evidence that body size alters exogenous glucose oxidation rates during exercise. This study assessed whether larger people oxidize more exogenous glucose during exercise than smaller people. Fifteen cyclists were allocated into two groups based on body mass (SMALL, <70 kg body mass, n = 9, two females) or (LARGE, >70 kg body mass, n = 6) matched for lactate threshold (SMALL: 2.3 ± 0.4 W/kg, LARGE: 2.3 ± 0.3 W/kg). SMALL completed 120 min of cycling at 95% of lactate threshold1. LARGE completed two trials in a random order, one at 95% of lactate threshold1 (thereby exercising at the same relative intensity [RELATIVE]) and one at an absolute intensity matched to SMALL (ABSOLUTE). In all trials, cyclists ingested 90 g/hr of 13C-enriched glucose. Total exogenous glucose oxidation was (mean ± SD) 33 ± 8 g/hr in SMALL versus 45 ± 13 g/hr in LARGE-RELATIVE (mean difference: 13 g/hr, 95% confidence interval [2, 24] g/hr, p = .03). Large positive correlations were observed for measures of exogenous carbohydrate oxidation versus body size (body mass, height, and body surface area; e.g., body surface area vs. peak exogenous glucose oxidation, r = .85, 95% confidence interval [.51, .95], p < .01). When larger athletes reduced the intensity from RELATIVE to ABSOLUTE, total exogenous glucose oxidation was 39 ± 7 g/hr (p = .43 vs. LARGE-RELATIVE). In conclusion, the capacity for exogenous glucose oxidation is, on average, higher in larger athletes than smaller athletes during exercise. The extent to which this is due to higher absolute exercise intensity requires further research, but body size may be a consideration in tailoring sports nutrition guidelines for carbohydrate intake during exercise.
Soil nitrogen-related functional genes undergo abundance changes during vegetation degradation in a Qinghai-Tibet Plateau wet meadow
Authors: Du Jianan , Ma Weiwei , Li Guang , Chang Wenhua , Chun Longyong 
Published: September 2024

ABSTRACT

Climate change and anthropogenic activities have significantly contributed to the degradation of wet meadows on the Qinghai-Tibet Plateau (QTP). Soil nitrogen (N) availability is a crucial determinant of the productivity of wet meadow vegetation. Furthermore, soil microbial nitrogen functional genes (NFGs) are critical in the transformation of soil N. Nevertheless, the dynamics of NFGs in response to vegetation degradation, as well as the underlying drivers, remain poorly understood. In this study, wet meadows at varying levels of vegetation degradation on the QTP, categorized as non-degraded (ND), slightly degraded (SD), moderately degraded (MD), and heavily degraded (HD), were examined. Soil samples from depths of 0 to 10 cm and 10 to 20 cm were collected during different growth cycles (June 2020, August 2020, and May 2021). The analysis focused on NFGs involved in organic nitrogen fixation (
nifH
), archaeal and bacterial ammonia oxidation (
amoA-AOA
and
amoA-AOB
, respectively), and nitrite reduction (
nirK
), utilizing real-time fluorescence quantitative PCR. Our findings indicate a significant decline in the abundance of NFGs with intensified vegetation degradation, exhibiting notable spatial and temporal fluctuations. Specifically, the relative NFGs followed the pattern:
nirK
>
amoA-
AOA >
amoA-
AOB >
nifH
. Redundancy analysis revealed that vegetation cover was the primary regulator of NFGs abundance, accounting for 56.1%–57% of the variation. Additionally, soil total nitrogen, pH, and total phosphorus content were responsible for 38.5%, 28.2%, and 7% of the variability in NFGs, respectively. The (
amoA-AOA + amoA-AOB + nirK
) ratios associated with effective N transformation indicated that the vegetation degradation process moderately increased the nitrification potential.

IMPORTANCE
Our research investigates how the degradation of meadows affects the tiny organisms in soil that help plants use nitrogen, which is essential for their growth. In the Qinghai-Tibet Plateau, a region known for its unique ecosystems, we found that as meadows deteriorate—due to climate change and human activities—the number of these beneficial organisms significantly decreases. This decline could reduce soil fertility, impacting plant life and the overall health of the ecosystem. Understanding these changes helps us grasp how environmental pressures influence soil and plant health. Such knowledge is crucial for developing strategies to preserve these vulnerable ecosystems and ensure they continue to sustain biodiversity and provide resources for local communities.
The hindgut microbiota of coconut rhinoceros beetles (
Oryctes rhinoceros
) in relation to their geographical populations
Authors: Han Chiao-Jung , Huang Jen-Pan , Chiang Min-Rou , Jean Ok Shin Malagayo , Nand Nitesh , Etebari Kayvan , Shelomi Matan 
Published: September 2024

ABSTRACT

The coconut rhinoceros beetle (CRB,
Oryctes rhinoceros
) is a palm tree pest capable of rapidly expanding its population in new territories. Previous studies identified a digestive symbiosis between CRB and its gut microbes. However, no research compared the genetic variation of CRBs with their hindgut microbiota on a global scale. This study aims to investigate the genetic divergence of CRB and the compositional variation of CRB’s microbiota across different geographical locations, and explore the association between them and their predicted functional profiles and environmental data. The research reveals a distinct and consistent microbial community within local populations, but it varies across different geographical populations. The microbial functional profiles linked to the production of digestive enzymes, including cellulases and ligninases, are nonetheless globally conserved. This suggests that CRBs employ specific mechanisms to select and maintain microbes with functional benefits, contributing to host adaptability, stress tolerance, and fitness. The CRB microbial communities did not appear to recapitulate the genetic variation of their hosts. Rather than depend on obligate symbionts, CRBs seem to establish similar digestive associations with whatever environmentally acquired microbes are available wherever they are, aiding them in successfully establishing after invading a new location.

IMPORTANCE
Coconut rhinoceros beetles (CRBs) are notorious pests on Arecaceae plants, posing destructive threats to countries highly reliant on coconut, oil palm, and date palm as economic crops. In the last century, CRBs have rapidly expanded their presence to territories that were once free of these beetles. The United States, for instance, has officially designated CRBs as invasive and alien pests. Given their remarkable ability to swiftly adapt to new environments, their gut microbes may play a crucial role in this process. While the microbiota of CRBs vary depending on geographical location, these beetles consistently exhibit a functionally identical digestive association with locally acquired microbes. This underscores the significance of CRB-microbe association in shaping the adaptive strategies of this agricultural pest.
Discovery of a novel methionine biosynthetic route
via O
-phospho-
l
-homoserine
Authors: Hasebe Fumihito , Adachi Kazuya , Maruyama Chitose , Hamano Yoshimitsu 
Published: September 2024

ABSTRACT

Methionine (Met), a sulfur-containing amino acid, is essential for the underlying biological processes in living organisms. In addition to its importance as a starting building block for peptide chain elongation in protein biosynthesis, Met is a direct precursor of
S
-adenosyl-
l
-methionine, an indispensable methyl donor molecule in primary and secondary metabolism.
Streptomyces
bacteria are well known to produce diverse secondary metabolites, but many strains lack canonical Met pathway genes for
l
-homocysteine, a direct precursor of Met in bacteria, plants, and archaea. Here, we report the identification of a novel gene (
metM
) responsible for the Met biosynthesis in
Streptomyces
strains and demonstrate the catalytic function of the gene product, MetM. We further identified the
metO
gene, a downstream gene of
metM
, and showed that it encodes a sulfur-carrier protein (SCP). In
in vitro
analysis, MetO was found to play an important role in a sulfur donor by forming a thiocarboxylated SCP. Together with MetO (thiocarboxylate), MetM directly converted
O
-phospho-
l
-homoserine to
l
-homocysteine.
O
-Phospho-
l
-homoserine is also known as an intermediate for threonine biosynthesis in bacteria and plants, and MetM shares sequence homology with threonine synthase. Our findings thus revealed that MetM seizes
O
-phospho-
l
-homoserine from the threonine biosynthetic pathway and uses it as an intermediate of the Met biosynthesis to generate the sulfur-containing amino acid. Importantly, this MetM/MetO pathway is highly conserved in
Streptomyces
bacteria and distributed in other bacteria and archaea.

IMPORTANCE

Methionine (Met) is a sulfur-containing proteinogenic amino acid. Moreover, Met is a direct precursor of
S
-adenosyl-
l
-methionine, an indispensable molecule for expanding the structural diversity of natural products. Because Met and its derivatives benefit humans, the knowledge of Met biosynthesis is important as a basis for improving their fermentation.
Streptomyces
bacteria are well known to produce diverse and valuable natural products, but many strains lack canonical Met pathway genes. Here, we identified a novel
l
-homocysteine synthase (MetM) in
Streptomyces
and demonstrated that it converts
O
-phospho-L-homoserine to
l
-homocysteine using a thiocarboxylated sulfur-carrier protein as a sulfur donor. Since the
metM
is distributed in other bacteria and archaea, our pioneering study contributes to understanding Met biosynthesis in these organisms.