bluuebunny/crossref_metadata_2025 huggingface dataset:
Tree mortality 6 years after burning a thinned Quercuschrysolepis stand
Authors: Paysen Timothy E. , Narog Marcia G.
Published: July 2007

Managers do not currently use prescribed fire in stands of canyon live oak (Quercuschrysolepis Liebm.) because it is highly susceptible to fire injury. A preliminary study investigating the effects of prescribed burning on this species was initiated on the San Bernardino National Forest in southern California. The purpose was to assess the feasibility of using thinning and prescribed burning to develop shaded fuel breaks in these stands. This paper addresses aboveground tree mortality inventoried 2 and 6 years after a prescribed burn. Aboveground tree stems were judged as live or dead (irrespective of root-zone sprouting). Fire caused approximately 50% mortality in DBH classes ≤15 cm and <10% in larger classes. Between the 2nd and 6th years after burning, tree mortality increased by only 3%. Our results suggest that prescribed fire can be used as a management tool in Q. chrysolepis stands and that tree mortality might be evaluated sooner than previously believed. More investigations are required to identify favorable conditions for prescribed burning in this species, as well as applicability for (i) degree of hazard reduction near the urban wildland interface, (ii) stand improvement by thinning small or crowded trees, and (iii) revitalizing wildlife habitat.
Relationships among atmospheric deposition, throughfall, and soil properties in oak forest ecosystems
Authors: MacDonald Neil W. , Witter John A. , Burton Andrew J. , Pregitzer Kurt S. , Richter Daniel D.
Published: July 2007

Relationships among pollutant (H+, SO42−, NO3−) deposition, throughfall ionic fluxes, and soil properties were examined at six oak forest sites in the southern Great Lakes region. At each site, precipitation, throughfall, and soil samples were collected and chemically analyzed. Sulfate and NO3− deposition increased from southern Michigan to northern Ohio in both precipitation and throughfall. Throughfall H+ fluxes also increased between these two areas. Throughfall fluxes of H+, SO42−, NO3−, and Ca2+ were significantly related to wet pollutant deposition. Throughfall Ca2+ and Mg2+ fluxes also tended to reflect soil cation abundance, but H+ consumption in the canopy was a major contributor to cation fluxes at certain sites. After accounting for differences in inherent soil properties, additional variation in both surface and subsurface soil properties was statistically related to atmospheric deposition. While topographic position and impeded drainage also may be implicated, elevated extractable SO42−, decreased potential to adsorb SO42−, and lower nutrient cation saturation in the solum of the most polluted site were consistent with pollutant deposition impacts. Results suggest that certain oak ecosystems in the southern Great Lakes region have experienced alteration in throughfall chemistry and soil properties as a result of elevated pollutant deposition.
Susceptibility of Norway spruce plantations to white pine weevil attacks in southern Quebec
Authors: Archambault Louis , Morissette Jacques , Lavallée Robert , Comtois Bernard
Published: July 2007

Annual levels of attack by the white pine weevil (Pissodesstrobi Peck) in 110 Norway spruce (Piceaabies (L.) Karst.) plantations of southern Quebec were measured. The relationships between levels of attack and site and stand characteristics were determined. In 1991, 84% of the plantations were affected by the weevil. Annual levels of attack increased from 2 to 25% of the trees between 1987 and 1991 for the 110 plantations. Drainage and site quality index influenced the levels of attack. On medium-textured soil ecosystems, plantations situated on imperfectly drained soils were significantly more affected (43%) than those on well-drained soils (11%). Plantations located on the most productive sites (site quality index 13–14 m at 25 years) were less affected (8%) than those on the least productive (7–8 m at 25 years) sites (34%). There was no significant correlation between plantation density and levels of attack. The results showed that the white pine weevil is one of the most damaging pests of Norway spruce plantations in southern Quebec. Norway spruce plantations should be monitored annually for damage detection. Appropriate sites should be selected for reforestation to maximize productivity and minimize insect damage.
Evaluation of simple quantile estimation functions for modeling forest diameter distributions in even-aged stands of interior Douglas-fir
Authors: Newberry James D. , Moore James A. , Zhang Lianjun
Published: July 2007

The method of percentiles usually involves simultaneously solving equations for probability distribution parameters as functions of sample-based estimates of the appropriate quantiles. Eight simple distribution-free methods for estimating quantiles from sample-based order statistics were evaluated empirically using even-aged Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) diameter distributions from the Inland Northwest. Two methods, calculated by weighting adjacent order statistics, consistently gave the best results for both the Weibull and Johnson's SB distributions. Certain distributional shapes were also evaluated to determine if they influenced the quantile estimation method. Although some influence was detected, the best methods were usually best across all categories.
Estimating forest canopy effects on summer thermal cover for Cervidae (deer family)
Authors: Demarchi M.W. , Bunnell F.L.
Published: July 2007

Operative temperatures of five members of the deer family under different forest canopies during summer were estimated. Sky view factors and effective leaf area indices were obtained from hemispherical photography. These were combined with radiation regime, ambient air temperature, wind speed, and other relevant factors to obtain operative temperature. Upper critical temperatures were significantly related to operative temperature in the open (r2 = 0.65; p < 0.05). To assess the thermal cover value of different canopy closures, simultaneous operative-temperature values as a function of canopy closure were estimated by simulation. Operative temperature decreased sharply with increasing crown closure up to about 30% crown closure, and then more gradually. Crown-closure values providing thermal cover under different ambient temperatures are summarized for the five deer taxa. Crown-closure classes as commonly depicted on forest cover maps correctly rank the effectiveness in providing summer thermal cover (r2 = 0.91; p < 0.05).
Temporal variations in the rooting ability of cuttings of Populusbalsamifera and Salixplanifolia from natural clones–populations of subarctic Quebec
Authors: Houle Gilles , Babeux Patrice
Published: July 2007

Temporal variations in the rooting ability of cuttings from five clones of Populusbalsamifera L. and five populations of Salixplanifolia Pursh from the Great Whale River valley in subarctic Quebec were determined. Cuttings were sampled monthly from May through October and rooted in a greenhouse. Root number and length of the longest root per cutting were determined 35 days after planting. There were significant variations among the six sampling dates in the rooting potential of cuttings of both species. A higher percentage of cuttings formed adventitious roots in May and June before or shortly after bud break than later, during the growing season; root number and length followed a similar trend. There was an increase in the rooting ability of cuttings of both species towards the fall period. Salixplanifolia produced more roots per cutting than P. balsamifera early in the season (i.e., May and June), but later in the season the differences between the two species were not great; root length showed no such trend. Differences among clones–populations in the rooting potential of cuttings were large for both species. Coefficients of variation for root number were lower in spring than later, during the growing season, for both P. balsamifera and S. planifolia. Seasonal trends in coefficients of variation for root length were not as evident as for root number. These results have significant implications for site restoration in the Subarctic. To optimize the rooting ability of cuttings and minimize the differences among clones–populations in rooting potential, cuttings should be sampled early in the season before bud break or shortly thereafter.
SIMULATION OF SHOCK-WAVE PROPAGATION WITH FINITE VOLUME LATTICE BOLTZMANN METHOD
Authors: QU KUN , SHU CHANG , CHEW YONG TIAN
Published: July 2007

A new approach was recently proposed to construct equilibrium distribution functions [Formula: see text] of the lattice Boltzmann method for simulation of compressible flows. In this approach, the Maxwellian function is replaced by a simple function which satisfies all needed relations to recover compressible Euler equations. With Lagrangian interpolation polynomials, the simple function is discretized onto a fixed velocity pattern to construct [Formula: see text]. In this paper, the finite volume method is combined with the new lattice Boltzmann models to simulate 1D and 2D shock-wave propagation. The numerical results agree well with available data in the literatures.
A COUPLED MOLECULAR-CONTINUUM HYBRID MODEL FOR THE SIMULATION OF MACROMOLECULAR DYNAMICS
Authors: GIUPPONI GIOVANNI , DE FABRITIIS GIANNI , COVENEY PETER V.
Published: July 2007

We describe a hybrid simulation method that captures the combined effects of molecular and hydrodynamic forces which influence macromolecules in solution. In this method, the solvent contribution is accounted for implicitly as the Navier-Stokes equations are solved on a grid using a finite volume method, while we use coarse-grained molecular dynamics to describe the macromolecule. The two systems are coupled by a dissipative Stokesian force. We show that our method correctly captures the hydrodynamically enhanced self-diffusion of a single monomer for different fluids and grid sizes. Moreover, the monomer diffusion does not depend on the monomer mass for the mass range used, as postulated by polymer dynamics theories. We also show that the dynamical properties of the chain do not depend on the grid size a when the chain radius of gyration Rg ≫ a.
EFFECTS OF ATOMISTIC DOMAIN SIZE ON HYBRID LATTICE BOLTZMANN–MOLECULAR DYNAMICS SIMULATIONS OF DENSE FLUIDS
Authors: DUPUIS A. , KOUMOUTSAKOS P.
Published: July 2007

We present a convergence study for a hybrid Lattice Boltzmann-Molecular Dynamics model for the simulation of dense liquids. Time and length scales are decoupled by using an iterative Schwarz domain decomposition algorithm. The velocity field from the atomistic domain is introduced as forcing terms to the Lattice Boltzmann model of the continuum while the mean field of the continuum imposes mean field conditions for the atomistic domain. In the present paper we investigate the effect of varying the size of the atomistic subdomain in simulations of two dimensional flows of liquid argon past carbon nanotubes and assess the efficiency of the method.
INFORMATION, INFORMATION PROCESSING AND GRAVITY
Authors: HSU STEPHEN D. H.
Published: July 2007

I discuss fundamental limits placed on information and information processing by gravity. Such limits arise because both information and its processing require energy, while gravitational collapse (formation of a horizon or black hole) restricts the amount of energy allowed in a finite region. Specifically, I use a criterion for gravitational collapse called the hoop conjecture. Once the hoop conjecture is assumed a number of results can be obtained directly: the existence of a fundamental uncertainty in spatial distance of order the Planck length, bounds on information (entropy) in a finite region, and a bound on the rate of information processing in a finite region. In the final section I discuss some cosmological issues, related to the total amount of information in the universe, and note that almost all detailed aspects of the late universe are determined by the randomness of quantum outcomes. This paper is based on a talk presented at a 2007 Bellairs Research Institute (McGill University) workshop on black holes and quantum information.
Angiotensin II attenuates myocardial interstitial acetylcholine release in response to vagal stimulation
Authors: Kawada Toru , Yamazaki Toji , Akiyama Tsuyoshi , Li Meihua , Zheng Can , Shishido Toshiaki , Mori Hidezo , Sugimachi Masaru
Published: July 2007

Although ANG II exerts a variety of effects on the cardiovascular system, its effects on the peripheral parasympathetic neurotransmission have only been evaluated by changes in heart rate (an effect on the sinus node). To elucidate the effect of ANG II on the parasympathetic neurotransmission in the left ventricle, we measured myocardial interstitial ACh release in response to vagal stimulation (1 ms, 10 V, 20 Hz) using cardiac microdialysis in anesthetized cats. In a control group ( n = 6), vagal stimulation increased the ACh level from 0.85 ± 0.03 to 10.7 ± 1.0 (SE) nM. Intravenous administration of ANG II at 10 μg·kg−1·h−1 suppressed the stimulation-induced ACh release to 7.5 ± 0.6 nM ( P < 0.01). In a group with pretreatment of intravenous ANG II receptor subtype 1 (AT1 receptor) blocker losartan (10 mg/kg, n = 6), ANG II was unable to inhibit the stimulation-induced ACh release (8.6 ± 1.5 vs. 8.4 ± 1.7 nM). In contrast, in a group with local administration of losartan (10 mM, n = 6) through the dialysis probe, ANG II inhibited the stimulation-induced ACh release (8.0 ± 0.8 vs. 5.8 ± 1.0 nM, P < 0.05). In conclusion, intravenous ANG II significantly inhibited the parasympathetic neurotransmission through AT1 receptors. The failure of local losartan administration to nullify the inhibitory effect of ANG II on the stimulation-induced ACh release indicates that the site of this inhibitory action is likely at parasympathetic ganglia rather than at postganglionic vagal nerve terminals.
Preservation of Rabbit Aorta Elastin From Degradation by Gingival Fibroblasts in an Ex Vivo Model
Authors: Gogly Bruno , Naveau Adrien , Fournier Benjamin , Reinald Nicoleta , Durand Eric , Brasselet Camille , Coulomb Bernard , Lafont Antoine
Published: July 2007

Objective—

Embryo-like gingival healing properties are attributed to the gingival fibroblast (GF) and could be used as a model for other types of healing dysfunctions. Abdominal aortic aneurysm (AAA) formation is associated with elastin degradation and increase in matrix metalloproteinase (MMP)-9 activity. We aimed to validate the concept of using GF healing properties in arteries.

Methods and Results—

We evaluated MMP-9 and its tissue inhibitor (TIMP-1) in rabbit aortic rings cultured in collagen gels with or without GFs and observed throughout 21 days. We also performed cocultures of human smooth muscle cells (hSMCs) with either gingival, dermal, or adventitial fibroblasts, and alone (control). In control arteries, elastic fibers became spontaneously sparse. In presence of GFs, elastic fibers were preserved. There was a dramatically reduced protein level of MMP-9 in coculture of aorta and GFs, in contrast with control aorta. MMP-9 expression was unaffected by GFs. MMP-9 inhibition was related to increased TIMP-1 secretion, TIMP-1 forming a complex with MMP-9. Cell cocultures of hSMC with GFs showed similar results. Dermal and adventitial fibroblasts did not affect MMP-9.

Conclusions—

Elastic fiber degradation was specifically preserved by GFs via reduction of MMP-9 protein level by increasing TIMP-1 synthesis. Vascular transfer of gingival fibroblasts could be a promising approach to treat AAA.
Pentaerythrityl Tetranitrate and Nitroglycerin, but not Isosorbide Mononitrate, Prevent Endothelial Dysfunction Induced by Ischemia and Reperfusion
Authors: Dragoni Saverio , Gori Tommaso , Lisi Monica , Di Stolfo Giuseppe , Pautz Andrea , Kleinert Hartmut , Parker John D.
Published: July 2007

Background—

Short term exposure to nitroglycerin (GTN) has protective properties that are similar to ischemic preconditioning. Whether other organic nitrates such as pentaerithrityl tetranitrate (PETN) and isosorbide mononitrate (ISMN) have similar protective effects has not been explored.

Methods and Results—

In a randomized, parallel, double blind, controlled trial, 37 healthy young volunteers received no therapy (n=10), transdermal GTN 1.2 mg for 2 hours (n=9), PETN 80 mg (n=9), or ISMN 40 mg (n=9). Twenty-four hours later, endothelium-dependent flow-mediated vasodilation (FMD) was measured before and after local exposure to ischemia and reperfusion (IR). In the no therapy group, IR blunted FMD (FMD after IR: 1.9±0.6%,
P
<0.05), an effect that was prevented by GTN (FMD after IR: 5.3±1.4%,
P
<0.05 compared with no therapy). PETN had the same protective effect (FMD after IR: 8.1±1.3%,
P
<0.05 compared with no therapy), whereas ISMN had no significant pharmacological preconditioning effect (FMD after-IR: 3.6±0.8%,
P
=ns compared with no therapy). While it blocked the effect of GTN, Vitamin C (n=8) did not modify PETN preconditioning (FMD after IR: 6.3±0.9%,
P
=ns compared with before IR), showing that this phenomenon is not mediated by oxygen free radical production. In an effort to identify the mechanism of PETN preconditioning, isolated human endothelial cells were incubated with PETN, GTN, or ISMN. Only PETN induced expression of the genes encoding for heme oxygenase and ferritin, which have been involved in ischemic and pharmacological preconditioning.

Conclusions—

We show important differences among organic nitrates in their capacity to prevent IR-induced endothelial dysfunction. GTN and PETN, but not ISMN, have this preconditioning effect. The potential clinical implications of these data warrant further investigation.
Electrophysiological Maturation and Integration of Murine Fetal Cardiomyocytes After Transplantation
Authors: Halbach Marcel , Pfannkuche Kurt , Pillekamp Frank , Ziomka Agnieszka , Hannes Tobias , Reppel Michael , Hescheler Juergen , Müller-Ehmsen Jochen
Published: July 2007

In the present study, we investigated the electrophysiological maturation and integration of immature cardiomyocytes after transplantation; maturation and integration are essential to achieve the cardiac regeneration. Murine fetal cardiomyocytes (FCMs) (d12.5-d15.5) expressing enhanced green fluorescent protein under the control of the α-actin promoter were injected into cryoinjured areas and adjacent myocardium of cryoinjured mouse ventricles. Viable short axis tissue slices (thickness, 150 μm) of the ventricles were prepared 5 to 6 days after transplantation. Glass microelectrodes were used for measurements of action potentials in transplanted FCMs and host cardiomyocytes within the slices. Stimulation at frequencies of up to 10 Hz was performed via a unipolar electrode placed in viable host tissue. Transplanted FCMs could be distinguished clearly from host tissue by their green fluorescence and their electrophysiological properties: maximal upstroke velocity (
V
max
) was significantly lower and action potential duration at 50% repolarization (APD
50
) was significantly longer compared with values of adult cardiomyocytes. Transplanted FCMs surrounded by cryoinjured tissue showed spontaneous electrical and contractile activity, which was in no case synchronous with host tissue.
V
max
and APD
50
of these nonintegrated cells matched values of cultivated dissociated FCMs. In contrast, 82% of transplanted FCMs surrounded by viable host tissue were electrically integrated; ie, electrical and contractile activity was synchronous with host tissue and these cells had more mature action potential parameters (significantly higher
V
max
and shorter APD
50
) compared with nonintegrated FCMs. In conclusion, electrophysiological maturation and integration of transplanted FCMs depend on an embedment in viable host myocardium. FCMs surrounded by cryoinjured tissue maintain physiological but immature AP properties.
Accuracy and quality of massively parallel DNA pyrosequencing
Authors: Huse Susan M , Huber Julie A , Morrison Hilary G , Sogin Mitchell L , Welch David Mark
Published: July 2007

Background

Massively parallel pyrosequencing systems have increased the efficiency of DNA sequencing, although the published per-base accuracy of a Roche GS20 is only 96%. In genome projects, highly redundant consensus assemblies can compensate for sequencing errors. In contrast, studies of microbial diversity that catalogue differences between PCR amplicons of ribosomal RNA genes (rDNA) or other conserved gene families cannot take advantage of consensus assemblies to detect and minimize incorrect base calls.

Results

We performed an empirical study of the per-base error rate for the Roche GS20 system using sequences of the V6 hypervariable region from cloned microbial ribosomal DNA (tag sequencing). We calculated a 99.5% accuracy rate in unassembled sequences, and identified several factors that can be used to remove a small percentage of low-quality reads, improving the accuracy to 99.75% or better.

Conclusion

By using objective criteria to eliminate low quality data, the quality of individual GS20 sequence reads in molecular ecological applications can surpass the accuracy of traditional capillary methods.
Social Isolation Affects the Development of Obesity and Type 2 Diabetes in Mice
Authors: Nonogaki Katsunori , Nozue Kana , Oka Yoshitomo
Published: July 2007

Social isolation is associated with increased risks of mortality and morbidity. In this study, we show that chronic individual housing accelerated body weight gain and adiposity in KK mice but not C57BL6J mice, and fully developed diabetes in KKAy mice. Individually housed KK and KKAy mice increased body weight gain over the initial 2 wk without increased daily average food consumption compared with group-housed animals. The individually housed KK and KKAy mice then gradually increased food consumption for the next 1 wk. The chronic social isolation-induced obesity (SIO) was associated with hyperleptinemia and lower plasma corticosterone and active ghrelin levels but not hyperinsulinemia. Elevated plasma leptin in the SIO suppressed expression of 5-HT2C receptor in white adipose tissue. The SIO was also associated with decreased expression of β3-adrenergic receptors in white adipose tissue and hypothalamic leptin receptor, which might be secondary to the enhanced adiposity. Interestingly, social isolation acutely reduced food consumption and body weight gain compared with group-housed obese db/db mice with leptin receptor deficiency. Social isolation-induced hyperglycemia in KKAy mice was associated with increased expression of hepatic gluconeogenetic genes independent of insulin. These findings suggest that social isolation promotes obesity due to primary decreased energy expenditure and secondary increased food consumption, which are independent of the disturbed leptin signaling, in KK mice, and develops into insulin-independent diabetes associated with increased expression of hepatic gluconeogenetic genes in KKAy mice. Thus, social isolation can be included in the environmental factors that contribute to the development of obesity and type 2 diabetes.
Role and Regulation of the Serum- and Glucocorticoid-Regulated Kinase 1 in Fertile and Infertile Human Endometrium
Authors: Feroze-Zaidi Fakhera , Fusi Luca , Takano Masashi , Higham Jenny , Salker Madhuri S. , Goto Tomoko , Edassery Seby , Klingel Karin , Boini Krishna Murthy , Palmada Monica , Kamps Rick , Groothuis Patrick G. , Lam Eric W.-F. , Smith Stephen K. , Lang Florian , Sharkey Andrew M. , Brosens Jan J.
Published: July 2007

Using cDNA microarray analysis, we identified SGK1 (serum- and glucocorticoid-regulated kinase 1) as a gene aberrantly expressed in midsecretory endometrium of women with unexplained infertility. SGK1 is a serine/threonine kinase involved primarily in epithelial ion transport and cell survival responses. Real-time quantitative PCR analysis of a larger, independent sample set timed to coincide with the period of uterine receptivity confirmed increased expression of SGK1 transcripts in infertile women compared with fertile controls. We further demonstrate that SGK1 expression is regulated by progesterone in human endometrium in vivo as well as in explant cultures. During the midsecretory phase of the cycle, SGK1 mRNA and protein were predominantly but not exclusively expressed in the luminal epithelium, and expression in this cellular compartment was higher in infertile women. In the stromal compartment, SGK1 expression was largely confined to decidualizing cells adjacent to the luminal epithelium. In primary culture, SGK1 was induced and phosphorylated upon decidualization of endometrial stromal cells in response to 8-bromo-cAMP and progestin treatment. Moreover, overexpression of SGK1 in decidualizing cells enhanced phosphorylation and cytoplasmic translocation of the forkhead transcription factor FOXO1 and inhibited the expression of PRL, a major decidual marker gene. Conversely, knockdown of endogenous SGK1 by small interfering RNA increased nuclear FOXO1 levels and enhanced PRL expression. The observation that SGK1 targets FOXO1 in differentiating human endometrium, together with its distinct temporal and spatial expression pattern and increased expression in infertile patients, suggest a major role for this kinase in early pregnancy events.
Mucus function and crossflow filtration in a fish with gill rakers removed versus intact
Authors: Smith Jennifer C. , Sanderson S. Laurie
Published: July 2007

Filtration mechanisms are known for only two species of suspension-feeding tilapia, each of which relies on a different method of particle retention. We used high-speed video endoscopy to assess whether a third species of tilapia, Oreochromis aureus, with gill rakers intact as well as surgically removed, uses mucus in the oropharyngeal cavity for hydrosol filtration or uses crossflow filtration to retain particles during suspension feeding. Although a large amount of mucus was visible during feeding with rakers intact, particles were rarely retained in the mucus. The hypothesis that the presence of mucus results in particle entrapment by hydrosol filtration is rejected for O. aureus. Rather than functioning as a sticky filter,mucus is proposed to function in this species to regulate the loss of water between the rakers and between the anterior branchial arches, increasing crossflow speed and thereby increasing the inertial lift force that transports particles radially away from the arches. Gill raker removal resulted in an almost complete lack of observable mucus in the oropharyngeal cavity, probably due to the removal of mucus-secreting cells attached to the gill rakers. However, endoscopic videotapes showed that crossflow filtration continued to operate in the absence of gill rakers and mucus, indicating that the surfaces of the branchial arches play an important role in crossflow filtration.
Self-Renewal and Multilineage Differentiation In Vitro from Murine Prostate Stem Cells
Authors: Xin Li , Lukacs Rita U. , Lawson Devon A. , Cheng Donghui , Witte Owen N.
Published: July 2007

Murine prostate stem cells express integrin α6, which modulates survival, proliferation, and differentiation signaling through its interaction with the extracellular protein laminin. When plated in vitro in laminin containing Matrigel medium, 1 of 500–1,000 murine prostate cells can grow and form clonogenic spheroid structures that we term prostate spheres. Prostate spheres can be serially passaged individually or in bulk to generate daughter spheres with similar composition, demonstrating that sphere-forming cells are capable of self-renewal. Spheres spontaneously undergo lineage specification for basal and transit-amplifying cell types. P63-expressing cells localized to the outer layers of prostate spheres possess higher self-renewal capacity, whereas cells toward the center display a more differentiated transit-amplifying phenotype, as demonstrated by the expression of the prostate stem cell antigen. When dihydrotestosterone is added to the medium, the androgen receptor is stabilized, is imported to the nucleus, and drives differentiation to a luminal cell-like phenotype. A fraction of sphere cells returned to an in vivo environment can undergo differentiation and morphogenesis to form prostate tubular structures with defined basal and luminal layers accompanied by prostatic secretions. This study demonstrates self-renewal and multilineage differentiation from single adult prostate stem/progenitor cells in a specific in vitro microenvironment.

Disclosure of potential conflicts of interest is found at the end of this article.
What Is Hyperthyroidism?
Authors: Voelker Rebecca
Published: March 2024

This JAMA Patient Page describes hyperthyroidism causes, symptoms, diagnosis, and treatment options.
Skin marker combined with surface‐guided auto‐positioning for breast DIBH radiotherapy daily initial patient setup: An optimal schedule for both accuracy and efficiency
Authors: Lai Jianjun , Luo Zhizeng , Jiang Lu , Hu Haili , Gao Chang , Zhang Chuanfeng , Chen Liting , Wu Jing , Wu Zhibing
Published: March 2024

Background and purpose

By employing three surface‐guided radiotherapy (SGRT)‐assisted positioning methods, we conducted a prospective study of patients undergoing SGRT‐based deep inspiration breath‐hold (DIBH) radiotherapy using a Sentine/Catalys system. The aim of this study was to optimize the initial positioning workflow of SGRT‐DIBH radiotherapy for breast cancer.

Materials and methods

A total of 124 patients were divided into three groups to conduct a prospective comparative study of the setup accuracy and efficiency for the daily initial setup of SGRT‐DIBH breast radiotherapy. Group A was subjected to skin marker plus SGRT verification, Group B underwent SGRT optical feedback plus auto‐positioning, and Group C was subjected to skin marker plus SGRT auto‐positioning. We evaluated setup accuracy and efficiency using cone‐beam computed tomography (CBCT) verification data and the total setup time.

Results

In groups A, B, and C, the mean and standard deviation of the translational setup‐error vectors were small, with the highest values of the three directions observed in group A (2.4 ± 1.6, 2.9 ± 1.8, and 2.8 ± 2.1 mm). The rotational vectors in group B (1.8 ± 0.7°, 2.1 ± 0.8°, and 1.8 ± 0.7°) were significantly larger than those in groups A and C, and the Group C setup required the shortest amount of time, at 1.5 ± 0.3 min, while that of Group B took the longest time, at 2.6 ± 0.9 min.

Conclusion

SGRT one‐key calibration was found to be more suitable when followed by skin marker/tattoo and in‐room laser positioning, establishing it as an optimal daily initial set‐up protocol for breast DIBH radiotherapy. This modality also proved to be suitable for free‐breathing breast cancer radiotherapy, and its widespread clinical use is recommended.
Removable Additive Assists Blade‐Coated Large‐Area Organic Solar Cell Modules Fabricated with Non‐Halogenated Solvents Achieving Efficiency Over 16%
Authors: Liu Zekun , Fu Yingying , Wu Jiang , Yi Xueting , Zhao Mengan , Huang Minghui , Liu Jian , Xie Zhiyuan
Published: March 2024

The critical step in commercializing organic solar cells (OSCs) involves achieving high‐performance modules through environmentally friendly solvents. The incorporation of solid additives, recognized as an effective method for modulating the morphology of active layers through layer‐by‐layer (LBL) deposition, plays a significant role. Here, a novel volatile solid additive is introduced individually into the non‐halogenated solution of donor PM6 as a morphology‐modulating agent. The additive induces conformational and crystalline orientation change of PM6, resulting in enhanced and balanced charge transport in the active layer. With a focus on exciton dynamics, the optimized active layer inhibits the formation of low‐energy triplet states. It facilitates strong reverse hole transfer processes, leading to more efficient exciton dissociation. The final small‐area LBL blade‐coated OSCs fabricated under ambient conditions achieve a power conversion efficiency (PCE) of 18.42%. Furthermore, a large‐area module with an area of 28.82 cm2 is manufactured, achieving a PCE of 16.04% with a high geometric fill factor of 93.8%. This highlights the effective modulation of the active layer through the use of solid additives and provides a successful strategy for fabricating high‐performance OSC modules with non‐halogenated solvents.
Coral Polyp and Spine Dual‐Inspired Gradient Hierarchical Architecture for Ultrahigh‐Rate and Long‐Life Sodium Storage
Authors: Wang Zhen , Liu Yang , Guo Yunjie , Lin Jiasong , Liu Lizhong , You Kejia , Lin Qinghong , Sun Jiayu , Lin Liangxu , Zhao Yi , Huang Wei
Published: March 2024

Sodium‐ion batteries (SIBs) are promising alternatives to lithium‐ion batteries with similar working principles, cell structures, and material systems. However, attaining long‐term stability and high‐capacity performance of SIBs at ultrahigh rates remains a significant challenge due to the large ionic radius and slow kinetic behavior of Na+. Herein, a novel robust anode with a dual‐biomimetic gradient hierarchical architecture is proposed and provide a simple strategy to fabricate this sulfur‐doped mesoporous carbon concave hollow sphere/Ti3C2Tx MXene (SCMX) anode. In addition, Cu2S nanoparticles are in situ embedded into the SCMX architecture by electrochemical induction during the cycling process to act as active sites, which enhances the rate performance and cycling stability. Relying on its hybrid architecture and in situ formed Cu2S, this SCMX anode can achieve high ion accessibility, rich active sites, rapid charge transfer, and favorable structure stability, as disclosed by in/ex situ characterizations. As a result, it exhibits high reversible capacity (745.6 mAh g−1 at 0.2 A g−1), ultrahigh‐rate capability (380.5 mAh g−1 at 50.0 A g−1), and long cycling stability (98.2% capacity retention after 10 000 cycles at 80.0 A g−1). This work is anticipated to accelerate the development of high‐performance SIBs and offer distinctive inspiration for the design of electrode structures/systems.
Oxygen‐Poor Amorphous Heterostructure Derived from Nb2CTx Toward Superior Lithium‐Ion Storage
Authors: Yan Ziwei , Zhu Kefu , Xu Hanchen , Wei Shiqiang , Wen Wen , Wang Changda , Song Li
Published: March 2024

Due to the long‐range atomic disorder and more active sites, amorphous MXenes with better chemical reactivity and electrical conductivity, have attracted wide attention in energy storage devices. However, to reach the practical applications of MXenes, investigations into the best structure of the amorphous layer are essential. Here, the structure evolution of MXenes induced from ammonium persulfate is explored via synchrotron radiation X‐ray absorption spectroscopy. Then, a kind of oxygen‐poor amorphous heterojunction Nb2CTx MXene (a‐Nb2CTx) is designed. Benefitting from the oxygen‐poor amorphous heterojunction, the a‐Nb2CTx electrode exhibits excellent Li+ storage performance with a high discharge specific capacity of 382 mAh g−1 at 0.1 A g−1 and a long cycling stability of 300 mAh g−1 at 1.0 A g−1 after 800 cycles. Operando synchrotron X‐ray diffraction results reveal that oxygen‐poor amorphous heterojunction stabilizes Nb2CTx MXene from undergoing structural changes during cycling. This work provides new insights into the rational design of novel amorphous MXenes, which is of great significance for the development of MXenes and their applications in high‐performance energy storage systems.
A T‐Cell Inspired Sonoporation System Enhances Low‐Dose X‐Ray‐Mediated Pyroptosis and Radioimmunotherapy Efficacy by Restoring Gasdermin‐E Expression
Authors: Yin Hao , Hu Xiaoqu , Xie Congying , Li Yida , Gao Yanjun , Zeng Hanqian , Zhu Wenting , Xie Danli , Wang Qinyang
Published: March 2024

Genome editing has the potential to improve the unsatisfactory therapeutic effect of antitumor immunotherapy. However, the cell plasma membrane prevents the entry of almost all free genome‐manipulation agents. Therefore, a system can be spatiotemporally controlled and can instantly open the cellular membrane to allow the entry of genome‐editing agents into target cells is needed. Here, inspired by the ability of T cells to deliver cytotoxins to cancer cells by perforation, an ultrasound (US)‐controlled perforation system (UPS) is established to enhance the delivery of free genome‐manipulating agents. The UPS can perforate the tumor cell membrane while maintaining cell viability via a controllable lipid peroxidation reaction. In vitro, transmembrane‐incapable plasmids can enter cells and perform genome editing with the assistance of UPS, achieving an efficiency of up to 90%. In vivo, the UPS is biodegradable, nonimmunogenic, and tumor‐targeting, enabling the puncturing of tumor cells under US. With the application of UPS‐assisted genome editing, gasdermin‐E expression in 4T1 tumor‐bearing mice is successfully restored, which leads to pyroptosis‐mediated antitumor immunotherapy via low‐dose X‐ray irradiation. This study provides new insights for designing a sonoporation system for genome editing. Moreover, the results demonstrate that restoring gasdermin expression by genome editing significantly improves the efficacy of radioimmunotherapy.
Sequentially PVD‐Grown Indium and Gallium Selenides Under Compositional and Layer Thickness Variation: Preparation, Structural and Optical Characterization
Authors: Schmid Martina , Ketharan Mithuran , Lucaßen Jan , Kardosh Ihab
Published: March 2024

Group IIIA metal chalcogenides are an auspicious material system due to their variability of properties and hence the multitude of application options, for example, in the fields of optoelectronic, thermoelectric, piezo‐, and ferroelectric devices. Indium and gallium selenide films are innovatively grown in a sequential PVD (physical vapor deposition) process starting from metal precursor layers of various thicknesses, which are then subject to chalcogenization in different selenium contents. The resulting thin films are investigated for structural and optical properties by Raman, XRD (X‐ray diffraction), and UV–Vis–NIR spectrometry, revealing that all the compounds In2Se3, InSe, In4Se3, Ga2Se3, and GaSe as well as different polytypes can be achieved depending on the metal/chalcogen ratio. Results from Raman and XRD spectroscopy are highly consistent, and also from the optical measurements changes in absorption characteristics can be correlated. The results indicate, that by fine‐tuning the selenium content, deliberately growing ultra‐thin layers of the different indium and gallium phases will be possible, thus opening up a promising route for 2D material fabrication. Given the scalability of the fabrication method, it is highly promising for large‐scale deployment of the materials.
Dark‐Field Resonance Rayleigh Scattering Biosensor to Monitor Small Molecules and Determine the Secretory Ability of Single Neuron
Authors: Su Yi , Rong Guoguang , Bian Sumin , Wang Pengbo , Li Lingfei , Chen Yun‐Hsuan , Huang Chao , Zhang Hongyong , Sawan Mohamad
Published: March 2024

Accurate monitoring of small molecules and precise characterization of the secretory ability of neurons are essential for effective diagnosis of neurological diseases. However, existing technologies for monitoring small molecules only provide approximate results. Plasmonic‐based biosensors are a potential solution in this biological application. Nevertheless, optical sensing nanoparticles require precise control of interparticle distance, particle shape and morphology, which can be challenging. This article discovers that the trapping of small molecules to aptamers induces a conformational change that alters the nanostructure of irregularly shaped Au nanoclusters (NCs) and aptamers due to the strong structure‐property relationships of Au NC‐aptamers. This change can be detected via resonance Rayleigh scattering (RRS) intensity in the dark‐field. This new technology overcomes the challenges of precise control of individual nanoparticles and the difficulty of small spectral peak shifts. The Au NC‐aptamers sensing device has a detection limit of 0.112 pm for dopamine, and this work detects 0.226 pm of dopamine surrounding a single epileptic neuron in polarization, which is more than those of healthy neurons. Overall, this easy‐to‐fabricate Au NC‐aptamers‐based technology has a high potential for monitoring small molecules and determining the secretory ability of single neurons, which is not possible using traditional technologies.
Mechanical Properties of Single and Polycrystalline Solids from Machine Learning
Authors: Jalolov Faridun N. , Podryabinkin Evgeny V. , Oganov Artem R. , Shapeev Alexander V. , Kvashnin Alexander G.
Published: March 2024

Calculating the elastic and mechanical characteristics of non‐crystalline solids can be challenging due to the high computational cost of ab initio methods and the low accuracy of empirical potentials. This paper proposes a computational technique for efficient calculations of mechanical properties of polycrystals, composites, and multi‐phase systems from atomistic simulations with high accuracy and reasonable computational cost. The calculated elastic moduli of polycrystalline diamond and their dependence on grain size are determined using a developed approach based on actively learned machine learning interatomic potentials (MLIPs). These potentials are trained on local fragments of the polycrystalline system, and ab initio calculations are used to compute forces, stresses, and energies. This technique allows researchers to perform extensive calculations of the mechanical properties of complex solids with different compositions and structures, achieving high accuracy and facilitating the transition from ideal (single crystal) systems to more realistic ones.
Strengths and opportunities in research into extracellular matrix ageing: A consultation with the ECMage research community
Authors: Dalby Matthew J. , Pekovic‐Vaughan Vanja , Shanley Daryl P. , Swift Joe , White Lisa J. , Canty‐Laird Elizabeth G.
Published: March 2024

Ageing causes progressive decline in metabolic, behavioural, and physiological functions, leading to a reduced health span. The extracellular matrix (ECM) is the three‐dimensional network of macromolecules that provides our tissues with structure and biomechanical resilience. Imbalance between damage and repair/regeneration causes the ECM to undergo structural deterioration with age, contributing to age‐associated pathology. The ECM ‘Ageing Across the Life Course’ interdisciplinary research network (ECMage) was established to bring together researchers in the United Kingdom, and internationally, working on the emerging field of ECM ageing. Here we report on a consultation at a joint meeting of ECMage and the Medical Research Council / Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing, held in January 2023, in which delegates analysed the key questions and research opportunities in the field of ECM ageing. We examine fundamental biological questions, enabling technologies, systems of study and emerging in vitro and in silico models, alongside consideration of the broader challenges facing the field.
Navigating the fine line between focal atrial tachycardia and atrial flutter?
Authors: Rahimpour Feisal , Hemmati Roohullah , Anafje Mohsen , Soltani Hadis , Majid Haghjoo , Ebrahimi Pouya
Published: March 2024

Key Clinical Message

Focal atrial tachycardia (FAT) is an organized atrial rhythm >100 beats per minute initiated from a discrete origin and spreading over both atria in a centrifugal pattern. The arrhythmia may be sustained or incessant. Dynamic forms with recurrent interruptions and reinitiating may be frequent. In this report, we present a 36‐year‐old man who came to the emergency room complaining of palpitation and shortness of breath. All laboratory evaluations were normal. With an initial electrocardiogram (ECG) the patient was admitted with the initial diagnosis of atrial flutter. Finally, after the electrophysiologist's examination, with the diagnosis of FAT, ablation was successfully performed. Atrial tachycardia (AT), excluding atrial fibrillation (AF) and cavotricuspid isthmus‐dependent atrial flutter (AFL), account for 10% of supraventricular tachycardia referred for ablation procedures. More than 70% of these cases are focal and occur in patients with no records of cardiac surgery or ablation of AF. FAT originating from the right pulmonary veins (PV) can be challenging to differentiate from atrial flutter due to their proximity and overlapping symptoms. The right PV is close to the right atrium, and the abnormal electrical activity in FAT may mimic the organized circuit found in atrial flutter. Distinguishing between FAT and atrial flutter is crucial for choosing the best therapeutic option. This can be done most of the time by focusing on the differences in the pattern of their P and QRS waves, R‐R wave intervals, and also their baseline changes on ECG, as well as their cycle duration, response to adenosine and risk factors of the patient.
B cell responses and antibody‐based therapeutic perspectives in human cancers
Authors: Mandal Gunjan , Pradhan Suchismita
Published: March 2024

Background

Immuno‐oncology has been focused on T cell‐centric approaches until the field recently started appreciating the importance of tumor‐reactive antibody production by tumor‐infiltrating plasma B cells, and the necessity of developing novel therapeutic antibodies for the treatment of different cancers.

Recent Findings

B lymphocytes often infiltrate solid tumors and the extent of B cell infiltration normally correlates with stronger T cell responses while generating humoral responses against malignant progression by producing tumor antigens‐reactive antibodies that bind and coat the tumor cells and promote cytotoxic effector mechanisms, reiterating the fact that the adaptive immune system works by coordinated humoral and cellular immune responses. Isotypes, magnitude, and the effector functions of antibodies produced by the B cells within the tumor environment differ among cancer types. Interestingly, apart from binding with specific tumor antigens, antibodies produced by tumor‐infiltrating B cells could bind to some non‐specific receptors, peculiarly expressed by cancer cells. Antibody‐based immunotherapies have revolutionized the modalities of cancer treatment across the world but are still limited against hematological malignancies and a few types of solid tumor cancers with a restricted number of targets, which necessitates the expansion of the field to have newer effective targeted antibody therapeutics.

Conclusion

Here, we discuss about recent understanding of the protective spontaneous antitumor humoral responses in human cancers, with an emphasis on the advancement and future perspectives of antibody‐based immunotherapies in cancer.