bluuebunny/crossref_metadata_2025 huggingface dataset:
Herbivores disrupt the flow of food resources to termites in dryland ecosystems
Authors: Wijas Baptiste J. , Cornwell William K. , Letnic Mike
Published: March 2023

Irruption of herbivore populations due to the extirpation of predators has led to dramatic changes in ecosystem functioning worldwide. Herbivores compete with other species for their primary source of nutrition, plant biomass. Such competition is typically considered to occur between species in closely related clades and functional groups but could also occur with detritivores that consume senescent plant biomass. In this study, we tested predictions that in ecosystems where herbivores are not regulated by predators, their indirect impacts on dead vegetation increase with primary productivity and extend to termites that feed on senescent vegetation. We compared dead vegetation cover and termite activity in herbivore exclosures and associated grazed plots at three locations situated along a rainfall gradient in arid Australia where kangaroo populations have irrupted. Dead vegetation cover and termite activity increased with rainfall in ungrazed plots but showed a negligible response to rainfall in grazed plots. Our results suggest that grazing can disrupt the flow of energy to detritivores and decouple the relationship between termite activity and primary productivity. Such disruption could have far‐reaching impacts on arid ecosystems because many organisms sit within “brown food webs” that are sustained by energy derived from the decomposition of senescent plant tissues.
Chronotype and sleep disorders in children with epilepsy
Authors: Ozcelik Ayse Aysima , Karadag Mehmet
Published: March 2023

Objective

The circadian rhythm can affect the frequency and resistance of epileptic seizures. In this cross‐sectional study, we examined the impact of chronobiology and sleep disturbances on children with epilepsy.

Methods

One hundred and twenty‐five children and adolescents (55 patients and 70 controls) were included in the study. All participants were asked to complete the Revised Child Anxiety and Depression Scale—Child Version (RCADS‐CV), Sleep Disturbances Scale for Children (SDSC), Childhood Chronotype Questionnaire (CCQ).

Results

According to the CCQ results, controls had longer sleep duration (median 595 vs. 570), lower morningness–eveningness scores (median: 28 vs. 30), and higher rates of the morningness (12.9% vs. 1.8%) and intermediate (74.3% vs. 60%) chronotypes. The children and adolescents with epilepsy scored significantly higher in the Sleep breathing disorders (p = .001), Disorders of arousal nightmares (p = .044), Sleep–wake transition disorders (p = .037), Disorders of excessive somnolence (p = .001), and total SDCS (p = .046) scores. According to the RCADS‐CV results, the children with epilepsy scored significantly higher in all subscales in comparison to controls (p < .05).

Significance

Children and adolescents with epilepsy had shorter sleep duration were more likely to be evening‐oriented and had more significant sleep disturbance symptoms compared to controls.
Is thalamic deep brain stimulation synergistic with vagus nerve stimulation in drug‐resistant genetic generalized epilepsy?
Authors: Khan Aafreen , Middlebrooks Erik H. , Freund Brin , Grewal Sanjeet , Tatum William O.
Published: March 2023

Neuromodulation in epilepsy is a proven treatment for people with drug‐resistant focal epilepsy. Dual device therapies are increasingly utilized in people with drug‐resistant epilepsy. Vagus nerve stimulation (VNS) and deep brain stimulation (DBS) target the thalamus involving the primary neurobiological network in patients with genetic generalized epilepsy (GGE). We report a novel case of combined neuromodulation in a patient with drug‐resistant GGE who achieved a partial response with seizure reduction after VNS implantation yet following VNS‐DBS polyneurostimulation gradually achieved prolonged seizure freedom. We speculate that by combining the indirect activating effects of VNS with the direct inhibitory effects of DBS, this may provide synergy to thalamic modulated networks. We hypothesize a “rational polytherapy” may exist in some patients with GGE undergoing dual neuromodulation.
Functional connectivity between interoceptive brain regions is associated with distinct health‐related domains: A population‐based neuroimaging study
Authors: Luettich Alexander , Sievers Carolin , Alfaro Almagro Fidel , Allen Micah , Jbabdi Saad , Smith Stephen M. , Pattinson Kyle T. S.
Published: March 2023

Interoception is the sensation, perception, and integration of signals from within the body. It has been associated with a broad range of physiological and psychological processes. Further, interoceptive variables are related to specific regions and networks in the human brain. However, it is not clear whether or how these networks relate empirically to different domains of physiological and psychological health at the population level. We analysed a data set of 19,020 individuals (10,055 females, 8965 males; mean age: 63 years, age range: 45–81 years), who have participated in the UK Biobank Study, a very large‐scale prospective epidemiological health study. Using canonical correlation analysis (CCA), allowing for the examination of associations between two sets of variables, we related the functional connectome of brain regions implicated in interoception to a selection of nonimaging health and lifestyle related phenotypes, exploring their relationship within modes of population co‐variation. In one integrated and data driven analysis, we obtained four statistically significant modes. Modes could be categorised into domains of arousal and affect and cardiovascular health, respiratory health, body mass, and subjective health (all p < .0001) and were meaningfully associated with distinct neural circuits. Circuits represent specific neural “fingerprints” of functional domains and set the scope for future studies on the neurobiology of interoceptive involvement in different lifestyle and health‐related phenotypes. Therefore, our research contributes to the conceptualisation of interoception and may lead to a better understanding of co‐morbid conditions in the light of shared interoceptive structures.
Silencing hippocampal CA2 reduces behavioral flexibility in spatial learning
Authors: Lehr Andrew B. , Hitti Frederick L. , Deibel Scott H. , Stöber Tristan M.
Published: March 2023

The hippocampus is a key structure involved in learning and remembering spatial information. However, the extent to which hippocampal region CA2 is involved in these processes remains unclear. Here, we show that chronically silencing dorsal CA2 impairs reversal learning in the Morris water maze. After platform relocation, CA2‐silenced mice spent more time in the vicinity of the old platform location and less time in the new target quadrant. Accordingly, behavioral strategy analysis revealed increased perseverance in navigating to the old location during the first day and an increased use of non‐spatial strategies during the second day of reversal learning. Confirming previous indirect indications, these results demonstrate that CA2 is recruited when mice must flexibly adapt their behavior as task contingencies change. We discuss how these findings can be explained by recent theories of CA2 function and outline testable predictions to understand the underlying neural mechanisms. Demonstrating a direct involvement of CA2 in spatial learning, this work lends further support to the notion that CA2 plays a fundamental role in hippocampal information processing.
NMDA receptor activity during postnatal development determines intrinsic excitability and mossy fiber long‐term potentiation of CA3 pyramidal cells
Authors: Márquez Luis A. , Griego Ernesto , López Rubalcava Carolina , Galván Emilio J.
Published: March 2023

Experimental manipulations that interfere with the functional expression of N‐methyl‐D‐aspartate receptors (NMDARs) during prenatal neurodevelopment or critical periods of postnatal development are models that mimic behavioral and neurophysiological abnormalities of schizophrenia. Blockade of NMDARs with MK‐801 during early postnatal development alters glutamate release and impairs the induction of NMDAR‐dependent long‐term plasticity at the CA1 area of the hippocampus. However, it remains unknown if other forms of hippocampal plasticity, such as α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor (AMPAR)‐mediated short‐ and long‐term potentiation, are compromised in response to neonatal treatment with MK‐801. Consistent with this tenet, short‐ and long‐term potentiation between dentate gyrus axons, the mossy fibers (MF), onto CA3 pyramidal cells (CA3 PCs) are mediated by AMPARs. By combining whole‐cell patch clamp and extracellular recordings, we have demonstrated that transient blockade of NMDARs during early postnatal development induces a series of pre‐ and postsynaptic modifications at the MF—CA3 synapse. We found reduced glutamate release from the mossy boutons, increased paired‐pulse ratio, and reduced AMPAR‐mediated MF LTP levels. At the postsynaptic level, we found an altered NMDA/AMPA ratio and dysregulation of several potassium conductances that increased the excitability of CA3 PCs. In addition, MK‐801‐treated animals exhibited impaired spatial memory retrieval in the Barnes maze task. Our data demonstrate that transient hypofunction of NMDARs impacts NMDAR‐independent forms of synaptic plasticity of the hippocampus.
Noise response in monomolecular closed systems
Authors: Fajiculay Erickson , Hsu Chao‐Ping
Published: March 2023

One of the primary interests in understanding biological systems is the interaction between noise and cellular regulation. Noise levels can be altered by rate constant perturbations, which may result in an imbalance of important biological functions. Although the theory of noise localization can estimate noise perturbation response, it is currently limited to open systems, where the majority of biological networks belong. However, during their lifetime, some components of biological systems participate in reactions that can be categorized under a closed system. Therefore, a counterpart theory for closed systems is desirable. In this work, steady‐state perturbations of monomolecular closed systems and ways to estimate the response of noise as (co)variances are explored. We extend the structural sensitivity analysis for analyzing noise response patterns by using additional clues derived from multinomial assumptions. We identified scenarios in which this combination might fail in noise prediction, which we call noise flip, arising from the nonlinear dependence of variance upon composition. Nevertheless, theoretical intuition and simulation show that noise flip diminishes with increasing system size. This work provides an efficient and scalable means to estimate noise responses with potential applications in model discrimination, network‐wide response scanning, and reconstruction.
A laboratory model of canine search vigilance decrement, II: Noncontingent reward and Pavlovian appetitive stimuli
Authors: DeChant Mallory , Aviles Rosa Edgar O. , Prada‐Tiedemann Paola A. , Hall Nathaniel James
Published: March 2023

Detection dogs have demonstrated reduced performance in operational settings when required to search in an environment where few to no target odors are present. This study's purpose was to increase detection dog accuracy using noncontingent reward (NCR) and Pavlovian stimuli associated with reward. Eighteen dogs were randomly spilt into two groups and received four 40‐trial sessions in an operational and training context at 90% odor prevalence (baseline). Following baseline, in the operational context (now at 10% odor prevalence), experimental dogs received an NCR schedule consisting of delivering food rewards at the end of 66% of trials. After the NCR Test, dogs returned to baseline. During baseline, the experimental dogs received 10 days of delayed Pavlovian conditioning to a tone. During the test phase, the conditioned stimulus (tone) was presented to experimental dogs on average every two trials for 30 s in the operational context (now at 10% odor prevalence). Overall, NCR showed a nonsignificant trend for increased responding in the experimental group but tended to increase false alerts; therefore, a permutation of an NCR‐like reward schedule may maintain search. The Pavlovian conditioned stimulus didn't decrease timeouts or improve accuracy, but a within‐session analysis indicated that the dogs were more likely to time out and less likely to false alert when the tone was on than when it was off.
Novel nutrition strategies to enhance recovery after surgery
Authors: Martindale Robert G.
Published: March 2023

Surgery and traumatic injury set off a cascade of metabolic changes that are becoming better understood. Recently, strategies and protocols have been developed for optimizing outcomes, and this has yielded beneficial results. This brief review evaluates three specific nutrition or metabolic interventions in the postoperative setting that attempt to optimize outcomes. We limited this to three subspecialty areas including oncologic surgery, orthopedic surgery, and cardiac surgery. These agents included fish oils, factors to prevent dysbiosis, and resistance exercise and its role in enhancing protein update. Where these novel agents fit into the basic tenets of postoperative nutrition interventions does not change the narrative: deliver graduated early enteral feeding to attenuate the metabolic response to surgical stress, maintain the gastrointestinal mucosal barrier, use immune/metabolic modulation to enhance immune response while attenuating excessive inflammation, and support the microbiome.
THE IMPORTANCE OF BEING A DIVERSITY AND INCLUSION AMBASSADOR
Authors: Warren Celeste R.
Published: March 2023

The author, a longtime corporate executive, writes that “everyone must play a role in creating a diverse and inclusive work environment in any organization.” She notes that a “Diversity and Inclusion Ambassador is a person who acts as a representative or promoter of diversity and inclusion within the organization.” Her framework for becoming an ambassador is in three parts, which in her words are (1) Look at yourself. (2) Take an inventory of your surroundings. (3) Take action. In step one, “do a self‐reflection and assessment to determine what your strengths and areas of development are.” Step two involves “taking an inventory of your surroundings so you can know what to do to help others.” In step three, “you have to put into action the revelations you have after your initial assessments.” Ambassadors can be either individual contributors or C‐Suite leaders. Regarding the former, “For those employees who are not people managers, they are still instrumental to organizations creating a diverse and inclusive culture.” For the latter, “acting as a diversity and inclusion ambassador means that you are exemplifying the ideals of diversity and inclusion  and promoting those ideals to others throughout your organization.” Examples are provided for how to make these roles effective for both contributors and leaders.
THE HUMAN SIDE OF INNOVATION
Authors: Porcini Mauro
Published: March 2023

The author discusses his journey from growing up in the north of Italy to his current role as the first‐ever Chief Design Officer of PepsiCo, the food and beverage multinational corporation. He describes what he calls his mission of human‐centered innovation. What is required, he notes, is people whom he dubs “the unicorns.” He writes that “at PepsiCo, we have an organization of more than 300 design and innovation experts spread across fifteen locations in every region of the world with a full diversity of technical skills and personal backgrounds. Our innovation team has gained more than 1,800 awards and recognitions in less than ten years.” He stresses the importance of kindness in these unicorns, and that they “possess humanity, generosity, and sensitivity. They are transparent, sincere, and inspire trust.” Within himself, he cultivates an “insatiable curiosity for everything around me. Curiosity is a portal to access knowledge and an instigator for inspiration.” He says that society, especially through education systems, should help people develop the qualities of unicorns early in life. “I believe that,” he writes, “aside from teaching math, literature, geography, philosophy, and finance, schools everywhere should educate people on the qualities of the unicorns.”
Resolvent family for the evolution process with memory
Authors: Xu Gen Qi
Published: March 2023

In this paper, we investigate a class of the linear evolution process with memory in Banach space by a different approach. Suppose that the linear evolution process is well posed, we introduce a family pair of bounded linear operators, , that is, called the resolvent family for the linear evolution process with memory, the is called the memory effect family. In this paper, we prove that the families and are exponentially bounded, and the family associate with an operator pair that is called generator of the resolvent family. Using , we derive associated differential equation with memory and representation of via L. These results give necessary conditions of the well‐posed linear evolution process with memory. To apply the resolvent family to differential equation with memory, we present a generation theorem of the resolvent family under some restrictions on . The obtained results can be directly applied to linear delay differential equation, integro‐differential equation and functional differential equations.
Noncommutative Vieta theorem in Clifford geometric algebras
Authors: Shirokov Dmitry
Published: March 2023

In this paper, we discuss a generalization of Vieta theorem (Vieta's formulas) to the case of Clifford geometric algebras. We compare the generalized Vieta formulas with the ordinary Vieta formulas for characteristic polynomial containing eigenvalues. We discuss Gelfand–Retakh noncommutative Vieta theorem and use it for the case of geometric algebras of small dimensions. We introduce the notion of a simple basis‐free formula for a determinant in geometric algebra and prove that a formula of this type exists in the case of arbitrary dimension. Using this notion, we present and prove generalized Vieta theorem in geometric algebra of arbitrary dimension. The results can be used in symbolic computation and various applications of geometric algebras in computer science, computer graphics, computer vision, physics, and engineering.
Report on the AAPM deep‐learning spectral CT Grand Challenge
Authors: Sidky Emil Y. , Pan Xiaochuan
Published: March 2023

Background

This Special Report summarizes the 2022 AAPM Grand Challenge on Deep‐Learning spectral Computed Tomography (DL‐spectral CT) image reconstruction.

Purpose

The purpose of the challenge is to develop the most accurate image reconstruction algorithm possible for solving the inverse problem associated with a fast kilovolt switching dual‐energy CT scan using a three tissue‐map decomposition. Participants could choose to use a deep‐learning (DL), iterative, or a hybrid approach.

Methods

The challenge is based on a 2D breast CT simulation, where the simulated breast phantom consists of three tissue maps: adipose, fibroglandular, and calcification distributions. The phantom specification is stochastic so that multiple realizations can be generated for DL approaches. A dual‐energy scan is simulated where the x‐ray source potential of successive views alternates between 50 and 80 kilovolts (kV). A total of 512 views are generated, yielding 256 views for each source voltage. We generate 50 and 80 kV images by use of filtered back‐projection (FBP) on negative logarithm processed transmission data. For participants who develop a DL approach, 1000 cases are available. Each case consists of the three 512 × 512 tissue maps, 50 and 80‐kV transmission data sets and their corresponding FBP images. The goal of the DL network would then be to predict the material maps from either the transmission data, FBP images, or a combination of the two. For participants developing a physics‐based approach, all of the required modeling parameters are made available: geometry, spectra, and tissue attenuation curves. The provided information also allows for hybrid approaches where physics is exploited as well as information about the scanned object derived from the 1000 training cases. Final testing is performed by computation of root‐mean‐square error (RMSE) for predictions on the tissue maps from 100 new cases.

Results

Test phase submission were received from 18 research groups. Of the 18 submissions, 17 were results obtained with algorithms that involved DL. Only the second place finishing team developed a physics‐based image reconstruction algorithm. Both the winning and second place teams had highly accurate results where the RMSE was nearly zero to single floating point precision. Results from the top 10 also achieved a high degree of accuracy; and as a result, this special report outlines the methodology developed by each of these groups.

Conclusions

The DL‐spectral CT challenge successfully established a forum for developing image reconstruction algorithms that address an important inverse problem relevant for spectral CT.
Modeling the impact of tissue oxygen profiles and oxygen depletion parameter uncertainties on biological response and therapeutic benefit of FLASH
Authors: Zhu Hongyu , Schuemann Jan , Zhang Qixian , Gerweck Leo E.
Published: March 2023

Background

Ultra‐high dose rate (FLASH) radiation has been reported to efficiently suppress tumor growth while sparing normal tissue; however, the mechanism of the differential tissue sparing effect is still not known. Oxygen has long been known to profoundly impact radiobiological responses, and radiolytic oxygen depletion has been considered to be a possible cause or contributor to the FLASH phenomenon.

Purpose

This work investigates the impact of tissue pO2 profiles, oxygen depletion per unit dose (g), and the oxygen concentration yielding half‐maximum radiosensitization (the average of its maximum value and one) (k) in tumor and normal tissue.

Methods

We developed a model that considers the dependent relationship between oxygen depletion and change of radiosensitivity by FLASH irradiation. The model assumed that FLASH irradiation depletes intracellular oxygen more rapidly than it diffuses into the cell from the extracellular environment. Cell survival was calculated based on the linear quadratic‐linear model and the radiosensitivity related parameters were adjusted in 1 Gy increments of the administered dose. The model reproduced published experimental data that were obtained with different cell lines and oxygen concentrations, and was used to analyze the impact of parameter uncertainties on the radiobiological responses. This study expands the oxygen depletion analysis of FLASH to normal human tissue and tumor based on clinically determined aggregate and individual patient pO2 profiles.

Results

The results show that the pO2 profile is the most essential factor that affects biological response and analyses based on the median pO2 rather than the full pO2 profile can be unreliable and misleading. Additionally, the presence of a small fraction of cells on the threshold of radiobiologic hypoxia substantially alters biological response due to FLASH oxygen depletion. We found that an increment in the k value is generally more protective of tumor than normal tissue due to a higher frequency of lower pO2 values in tumors. Variation in the g value affects the dose at which oxygen depletion impacts response, but does not alter the dose‐dependent response trends, if the g value is identical in both tumor and normal tissue.

Conclusions

The therapeutic efficacy of FLASH oxygen depletion is likely patient and tissue‐dependent. For breast cancer, FLASH is beneficial in a minority of cases; however, in a subset of well oxygenated tumors, a therapeutic gain may be realized due to induced normal tissue hypoxia.
Prostate cancer segmentation from MRI by a multistream fusion encoder
Authors: Jiang Mingjie , Yuan Baohua , Kou Weixuan , Yan Wen , Marshall Harry , Yang Qianye , Syer Tom , Punwani Shonit , Emberton Mark , Barratt Dean C. , Cho Carmen C. M. , Hu Yipeng , Chiu Bernard
Published: March 2023

Background

Targeted prostate biopsy guided by multiparametric magnetic resonance imaging (mpMRI) detects more clinically significant lesions than conventional systemic biopsy. Lesion segmentation is required for planning MRI‐targeted biopsies. The requirement for integrating image features available in T2‐weighted and diffusion‐weighted images poses a challenge in prostate lesion segmentation from mpMRI.

Purpose

A flexible and efficient multistream fusion encoder is proposed in this work to facilitate the multiscale fusion of features from multiple imaging streams. A patch‐based loss function is introduced to improve the accuracy in segmenting small lesions.

Methods

The proposed multistream encoder fuses features extracted in the three imaging streams at each layer of the network, thereby allowing improved feature maps to propagate downstream and benefit segmentation performance. The fusion is achieved through a spatial attention map generated by optimally weighting the contribution of the convolution outputs from each stream. This design provides flexibility for the network to highlight image modalities according to their relative influence on the segmentation performance. The encoder also performs multiscale integration by highlighting the input feature maps (low‐level features) with the spatial attention maps generated from convolution outputs (high‐level features). The Dice similarity coefficient (DSC), serving as a cost function, is less sensitive to incorrect segmentation for small lesions. We address this issue by introducing a patch‐based loss function that provides an average of the DSCs obtained from local image patches. This local average DSC is equally sensitive to large and small lesions, as the patch‐based DSCs associated with small and large lesions have equal weights in this average DSC.

Results

The framework was evaluated in 931 sets of images acquired in several clinical studies at two centers in Hong Kong and the United Kingdom. In particular, the training, validation, and test sets contain 615, 144, and 172 sets of images, respectively. The proposed framework outperformed single‐stream networks and three recently proposed multistream networks, attaining F1 scores of 82.2 and 87.6% in the lesion and patient levels, respectively. The average inference time for an axial image was 11.8 ms.

Conclusion

The accuracy and efficiency afforded by the proposed framework would accelerate the MRI interpretation workflow of MRI‐targeted biopsy and focal therapies.
Deep learning‐based fast volumetric imaging using kV and MV projection images for lung cancer radiotherapy: A feasibility study
Authors: Lei Yang , Tian Zhen , Wang Tonghe , Roper Justin , Xie Huiqiao , Kesarwala Aparna H. , Higgins Kristin , Bradley Jeffrey D. , Liu Tian , Yang Xiaofeng
Published: March 2023

Purpose

The long acquisition time of CBCT discourages repeat verification imaging, therefore increasing treatment uncertainty. In this study, we present a fast volumetric imaging method for lung cancer radiation therapy using an orthogonal 2D kV/MV image pair.

Methods

The proposed model is a combination of 2D and 3D networks. The proposed model consists of five major parts: (1) kV and MV feature extractors are used to extract deep features from the perpendicular kV and MV projections. (2) The feature‐matching step is used to re‐align the feature maps to their projection angle in a Cartesian coordinate system. By using a residual module, the feature map can focus more on the difference between the estimated and ground truth images. (3) In addition, the feature map is downsized to include more global semantic information for the 3D estimation, which is useful to reduce inhomogeneity. By using convolution‐based reweighting, the model is able to further increase the uniformity of image. (4) To reduce the blurry noise of generated 3D volume, the Laplacian latent space loss calculated via the feature map that is extracted via specifically‐learned Gaussian kernel is used to supervise the network. (5) Finally, the 3D volume is derived from the trained model. We conducted a proof‐of‐concept study using 50 patients with lung cancer. An orthogonal kV/MV pair was generated by ray tracing through CT of each phase in a 4D CT scan. Orthogonal kV/MV pairs from nine respiratory phases were used to train this patient‐specific model while the kV/MV pair of the remaining phase was held for model testing.

Results

The results are based on simulation data and phantom results from a real Linac system. The mean absolute error (MAE) values achieved by our method were 57.5 HU and 77.4 HU within body and tumor region‐of‐interest (ROI), respectively. The mean achieved peak‐signal‐to‐noise ratios (PSNR) were 27.6 dB and 19.2 dB within the body and tumor ROI, respectively. The achieved mean normalized cross correlation (NCC) values were 0.97 and 0.94 within the body and tumor ROI, respectively. A phantom study demonstrated that the proposed method can accurately re‐position the phantom after shift. It is also shown that the proposed method using both kV and MV is superior to current method using kV or MV only in image quality.

Conclusion

These results demonstrate the feasibility and accuracy of our proposed fast volumetric imaging method from an orthogonal kV/MV pair, which provides a potential solution for daily treatment setup and verification of patients receiving radiation therapy for lung cancer.
ID Asks/Kenneth Werner
Authors: Peruvemba Sri
Published: March 2023

Engineer, journalist, editor, consultant, display industry storyteller, and flag bearer for SID
Generation of 3D geotechnical particles using random angular bend algorithm
Authors: Zhang Wengang , Han Liang , Wang Zhenyu , Liu Hanlong , Wang Luqi , Gao Xuecheng
Published: March 2023

Geo‐materials are generally regarded as multi‐phase structural systems, which are composed of particles, pores, and fissures. Generally, the shape and size of particles have considerable influence on the physical and mechanical properties of geo‐materials. Based on the theory of random angular bend (RAB) algorithm, this paper presented a method to finely generate the three‐dimensional (3D) random particle model via the superposition of two‐dimensional (2D) particle profiles, and this proposed method was coded in Python. According to the generation procedure, the relevant point cloud data should be generated, and with the aid of the point cloud normal vector calculation and Poisson reconstruction technique, the required 3D particle profiles can be obtained. Subsequently, three shape descriptors are selected to describe the shape characteristics of generated particles, and accordingly, the quantitative relationships between the shape descriptors and the input controlling parameters are established to accurately control the shape of generated particles. Finally, the generated geo‐material particles are implemented into the particle flow code (PFC3D) to construct the clump library, and an example about a 3D soil–rock mixture model was taken to validate the performance of the proposed method for numerical simulation. The results show that this study provides a useful strategy for the simulation of the geo‐materials based on the RAB theory.
13C NMR quantification of polyamine syntheses in rat prostate
Authors: Vandergrift Lindsey A. , Wang Nanbu , Zhu Miry , Li Bailing , Chen Shuyi , Habbel Piet , Nowak Johannes , Mason Ralph P. , Grant Aaron , Wang Yi , Malloy Craig , Cheng Leo L.
Published: March 2023

Currently, many prostate cancer patients, detected through the prostate specific antigen test, harbor organ‐confined indolent disease that cannot be differentiated from aggressive cancer according to clinically and pathologically known measures. Spermine has been considered as an endogenous inhibitor for prostate‐confined cancer growth and its expression has shown correlation with prostate cancer growth rates. If established clinically, measurements of spermine bio‐synthesis rates in prostates may predict prostate cancer growth and patient outcomes. Using rat models, we tested the feasibility of quantifying spermine bio‐synthesis rates with 13C NMR. Male Copenhagen rats (10 weeks, n = 6) were injected with uniformly 13C‐labeled L‐ornithine HCl, and were sacrificed in pairs at 10, 30, and 60 min after injection. Another two rats were injected with saline and sacrificed at 30 min as controls. Prostates were harvested and extracted with perchloric acid and the neutralized solutions were examined by 13C NMR at 600 MHz. 13C NMR revealed measurable ornithine, as well as putrescine‐spermidine‐spermine syntheses in rat prostates, allowing polyamine bio‐synthetic and ornithine bio‐catabolic rates to be calculated. Our study demonstrated the feasibility of 13C NMR for measuring bio‐synthesis rates of ornithine to spermine enzymatic reactions in rat prostates. The current study established a foundation upon which future investigations of protocols that differentiate prostate cancer growth rates according to the measure of ornithine to spermine bio‐synthetic rates may be developed.
Two‐dimensional correlated spectroscopy records reduced neurotransmission in blast‐exposed artillery soldiers after live fire training
Authors: Tosh Nathan , Watson Julia , Lukas Darren , Tremewan Rosanna , Beard Jason , Galloway Graham , Haselhorst Thomas , Young Ross , Crompton David , Mountford Carolyn
Published: March 2023

There is a requirement for an objective method to determine a safe level of low‐level military occupational blast, having recognised it can lead to neurological damage. The purpose of the current study was to evaluate the effect of artillery firing training on the neurochemistry of frontline soldiers using two‐dimensional (2D) COrrelated SpectroscopY (2D COSY) in a 3‐T clinical MR scanner. Ten men considered to be of sound health were evaluated before and after a week‐long live firing exercise in two ways. Prior to the live fire exercise, all participants were screened by a clinical psychologist using a combination of clinical interviews and psychometric tests, and were then scanned with 3‐T MRI. The protocols included T1‐ and T2‐weighted images for diagnostic reporting and anatomical localisation and 2D COSY to record any neurochemical effects from the firing. No changes to the structural MRI were recorded. Nine substantive and statistically significant changes in the neurochemistry were recorded as a consequence of firing training. Glutamine and glutamate, glutathione, and two of the seven fucose‐α (1–2)‐glycans were significantly increased. N‐acetyl aspartate, myo‐inositol + creatine, and glycerol were also increased. Significant decreases were recorded for the glutathione cysteine moiety and tentatively assigned glycan with a 1–6 linkage (F2: 4.00, F1: 1.31 ppm). These molecules are part of three neurochemical pathways at the terminus of the neurons providing evidence of early markers of disruption to neurotransmission. Using this technology, the extent of deregulation can now be monitored for each frontline defender on a personalised basis. The capacity to monitor early a disruption in neurotransmitters, using the 2D COSY protocol, can observe the effect of firing and may be used to prevent or limit these events.
Chylothorax and chylous ascites: Overview, management, and nutrition
Authors: Duletzke Nicholas T. , Kiraly Laszlo N. , Martindale Robert G.
Published: March 2023

Chyle leaks of any source or type can cause significant morbidity and mortality. Attention to the anatomy and physiology of the leak, followed by stepwise dietary and pharmacologic management, obviates the need for surgical intervention in a majority of patients. In this article, we review the importance, etiology, anatomy, diagnosis, nutrition and immunologic effects, and options for treatment of chylothorax and chylous ascites based on experience and prior literature. We propose a multidisciplinary approach to optimize these treatments including the primary surgical teams, pharmacists, and dietitians, with reoperation as a last resort to minimize the morbidity of this challenging complication.
Study on synthesis and mechanical properties of Eu3+‐π/covalent hybrid crosslinked silicone rubber
Authors: Yue Xuejun , Zeng Shangjun , Sun Rong , Li Yuqaun , Lu Ai , Kang Ming , Yu Fengmei
Published: March 2023

Silicone rubber is widely used in industry, dairy products, medical, defense support, and other fields due to its excellent comprehensive properties, which have become one of the most important research objects of high‐performance elastomer. Cationic‐π dynamic noncovalent bond has attracted more and more attention from material researchers due to its dynamic reversibility and design flexibility and has been applied to different material systems, giving new characteristics to traditional materials. Cationic‐π/covalently crosslinked silicone rubber was prepared by one‐step method with glycidol propyl terminated polydimethylsiloxane (DMS‐E21) as basic polymer, epoxy indole monomer (IN) as crosslinking structure modifier, Europium ion (Eu3+) as cation donor and triethylenetetramine (TETA) as a crosslinking agent. The influence of the reversibility of Eu3+‐π interaction on the static and dynamic mechanical behaviors of silicone rubber was studied. The results show that the elongation at break of cationic‐π/covalent hybrid crosslinked silicone rubber increases by more than 60% compared with pure covalent crosslinked silicone rubber when the breaking energy reaches the maximum, while the tensile strength increases by more than 100% and the introduction of Eu3+‐π dynamic bond can weaken the Mullins effect and the Payne effect on the high temperature of silicone rubber with obvious creep resistance. It shows an excellent mechanical strengthening effect with the characteristic of strengthening and toughening simultaneously and attractive nonlinear mechanical behavior on elastomers.
Caring for two in the ICU: Pharmacotherapy in the critically ill pregnant patient
Authors: Heavner Mojdeh S. , Erdman Grace , Barlow Brooke , Aldhaeefi Mohammed , Cucci Michaelia , Eng Claire C. , Hawkins W. Anthony , Rose Christina , Smith Susan E. , Bell Carolyn Magee , Lankford Allison , Li Matthew , Thompson Bastin Melissa L.
Published: March 2023

Safe and thoughtful medication management of pregnant patients requiring intensive care unit (ICU) level of care is key to optimizing outcomes for both mother and fetus. Pregnancy induces physiologic alterations that closely mirror the changes expected in a critically ill patient. These changes can be predictable depending on the gestational age and trimester and will directly impact the pharmacokinetic profile of medications commonly used in the ICU; examples include decreased gastric emptying, increased blood and plasma volume, increased glomerular filtration, and increased cardiac output. When pregnant patients require ICU care, the resulting impact on drug absorption, distribution, metabolism, and elimination can be difficult to predict. In addition, there are many nuances of medication metabolism and interface with the placental barrier that should be considered when selecting pharmacotherapy for the pregnant patient. Critical care clinicians need to be aware of medication interactions with the placenta and weigh the risk versus benefit profile of medication use in this patient population. Obstetric critical care admissions have increased over the years, especially during the coronavirus waves. Therefore, understanding the interplay between pregnancy and critical illness to optimize pharmacotherapy selection is crucial to improving health outcomes of mother and fetus. This review highlights pharmacotherapy considerations in the pregnant ICU patient for the following topics: physiologic alterations, categorizing medication risk, supportive care, sepsis, cardiogenic shock, acute respiratory distress syndrome, and venous thromboembolism.
Personalizing prevention: Advances in pharmacotherapy for HIV prevention
Authors: Brizzi Marisa , Sherman Elizabeth M. , Green Sarah B. , Nowicki Diana N. , Drwiega Emily N. , Nicol Melanie R. , Chastain Daniel B. , Sahloff Eric G. , Truong William R. , Cluck David , Badowski Melissa E. , Michienzi Sarah M. , Durham Spencer H.
Published: March 2023

The HIV epidemic continues to pose a significant burden on the healthcare system. Although the incidence of annual new infections is decreasing, health disparities persist and most new infections remain concentrated into different racial, ethnic, and minority groups. Pre‐exposure prophylaxis (PrEP), which involves those at high risk of acquiring HIV to take chronic medications to prevent acquisition of the virus, is key to preventing new HIV infections. The purpose of this article is to review medication therapies for PrEP and examine their role in personalizing PrEP in different patient populations. Additionally, new medications currently under development for PrEP are reviewed, as well as treatment as prevention (TasP) and post‐exposure prophylaxis (PEP). There are currently four medications available for PrEP: the oral options of co‐formulated emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) or emtricitabine/tenofovir alafenamide (FTC/TAF); injectable long‐acting cabotegravir (CAB‐LA); and the vaginal ring dapivirine (DPV‐VR). FTC/TAF is not currently indicated for persons at risk for HIV through vaginal sex due to lack of studies, but trials are currently ongoing. DPV‐VR is available in Zimbabwe and South Africa and has been endorsed by the World Health Organization but is not currently available in the United States. Several agents are also in development for use in PrEP: the novel long‐acting injectable lenacapavir, a first‐in‐class capsid inhibitor, which has no cross‐resistance to any existing HIV drug class; the subdermal implant islatravir, a first‐in‐class translocation inhibitor; and VRC01, a broadly neutralizing antibody (bnAb) which has been evaluated in proof‐of‐concept studies that may lead to the development of more potent bnAbs. Overall, PrEP is highly effective at preventing HIV infection in high‐risk populations. Identifying optimal PrEP regimens in different patient populations is complex and must consider patient‐specific factors and medication cost and access considerations. Lastly, providers should consider individual patient preferences with regard to prevention to improve access, retention in care, and adherence.
Capture of CO2by O, S, and Se substituted tripletN‐heterocyclic vinylidenes: a theoretical comparison
Authors: Soroudi Shadi , Kassaee Mohamad Zaman
Published: March 2023

Carbenes are anticipated to capture greenhouse gases. We have compared and contrasted trapping of CO2by O, S, and Se substituted singlet (s) and triplet (t)N‐heterocyclic vinylidene minima (1s–3sand1t–3t, respectively), at M06‐2X/6‐311++G** level of theory. Unlike many carbenes, our triplet minima (1t–3t) appeared as ground states. Hence, we compared their ability to capture CO2. The ease of CO2trapping by the scrutinized triplet vinylidenes is:2t > 3t > 1t. The NBO and AIM results appear consistent with the above trend and our proposed mechanism.
Solvent effect on adsorption of benzylidene oxindole to C20 nanocage: A DFT approach
Authors: Koohi Maryam , Bastami Hajieh
Published: March 2023

In this paper, one of the selective and potent inhibitors named (E)‐3‐benzylidene‐indoline‐2‐one (I), as against different receptor tyrosine kinase in metastasis, angiogenesis, and tumor growth, is inspected in the gas phase and in solution, at B3LYP/6‐311++G** and B3LYP/AUG‐cc‐pVTZ level of theory. A stimulating issue for this biologically active species is the effect of different media on its stability, structure, and energy gap in intermolecular [4 + 2] adsorption of I (as diene) to C20 (as dienophile) to yield (E)‐3‐benzylidene‐indoline‐2‐one[20]fullerene: Ia complex. In going from gas phase to C6H6, C2H4Cl2, EtOH, MeNO2, DMSO, and H2O solvents, individually, the optimization of complex (Ia) leads to the following: (1) The thermodynamic stability; the adsorption energy difference between liquid and gas phase (∆El–g) and dipole moment (μ) seem proportional to the dielectric constant (ε) of the scrutinized media. (2) The kinetic stability; energy difference (∆EL–H) between the frontier molecular orbitals; FMO in different media is altered in the opposite direction of ε. (3) Despite of popular belief that the endo isomer emerges thermodynamically more stable than its corresponding exo isomer, we suggest formation of kinetically more stable exo isomer because of π–π stacking among the benzyl ring and C20 nanocage. (4) The possibility of hetero [4 + 2] cycloaddition is anticipated by the lowest energy barrier of 3.8 kcal/mol probed for exo transition state (TS) in gas phase, while the highest energy barrier of 7.9 kcal/mol corresponds to the endo TS in water. (5) Due to lack of the repulsion type interaction, the exo [4 + 2] cycloaddition of unstable C20 fullerene with the scrutinized oxindole can be carried out thermally at r.t. and currently hold responsible for the origin of stereoselectivity.
Wetting and aging behaviors for several O2 and NH3 plasma treated nanofibrous and flat film polymer materials: A comparison
Authors: Watson Sean , Pattyn Cedric , Mohseni Garakani Mansoureh , Ajji Abdellah , Reuter Stephan , Wertheimer Michael R.
Published: March 2023

Aging (or “hydrophobic recovery”) of plasma‐modified polymer surfaces has been known and documented in the literature over several decades; to the best of our knowledge, the present study appears to be the first in which this is done for two vastly different rough surface structures: (i) electrospun nanofibrous (NF) mats, and (ii) flat films (FF), for three polymers of well‐documented interest in biotechnological applications: poly(lactic acid); poly(urethane); and poly(caprolactone). Two different plasma treatments are applied: low‐pressure (LP) radio‐frequency (rf) glow discharges in flows of O2 and NH3 under mild power conditions. Measured time‐dependent surface compositions (from X‐ray photoelectron spectroscopy survey spectra) and water contact angles (WCA) were found to tend toward asymptotic limiting values after ca. 30 days of storage in clean air, as previously reported by these and other authors. An entirely novel aspect of this work is to examine and compare time‐dependent WCA behaviors of NF and FF samples in terms of Wenzel (W) and Cassie‐Baxter (C‐B) model behaviors, including possible transitions from C‐B to W and their interpretation.
Laser‐Patterned Carbon‐Supported Graphitic Carbon Nitride Quantum Dots for Flexible Nanozyme‐Based Fluoride Sensor
Authors: Devi Mamta , Raut Bikash , Sharma Swati
Published: March 2023

Graphitic carbon nitride quantum dots (g‐CNQDs)‐based colorimetric sensors are typically solution‐based and hence incompatible with wearable electronics. Today's competitive technology demands safe and reliable, high‐performance sensors suitable for integration with sophisticated electronics—all at a low cost. Herein, a flexible and reusable solid‐state fluoride ion sensor manufactured by combining the intriguing surface properties of laser‐patterned carbon (LP‐C) with the sensitivity of g‐CNQDs is reported. LP‐C is obtained by direct IR‐laser writing onto polyimide films, and g‐CNQDs are synthesized via a solvent‐free and zero‐waste green process. The hybrid of LP‐C and g‐CNQDs (g‐CNQDs/LP‐C), mimics the natural enzyme horseradish peroxidase and oxidizes the chromogenic substrate 3,3’,5,5’‐tetramethylbenzidine in the presence of H2O2 in acidic media. The highly selective and user‐friendly nanozyme sensors feature a lower limit of detection of 0.568 ± 0.006  × 10−6 m (23.8 ± 1.5 µg L−1) with linearity in the range of 0.5 × 10−6 to 100  × 10−6 m. A sensing mechanism based on the electronic transitions of g‐CNQDs and LP‐C, the two variants of nitrogen‐containing carbon used in this work, is established. Finally, the device is tested for fluoride ion sensing in natural water samples collected from the Uhl river in Mandi, India.