bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships between Soil–Landscape and Dryland Cotton Lint Yield
Authors: Iqbal Javed , Read John J. , Thomasson Alex J. , Jenkins Johnie N.
Published: May 2005

Topographical land features shape the spatial variability of soils and crop yields, especially in dryland cotton (Gossypium hirsutumL.). The objectives of this study were to (i) quantify the relationships between cotton lint yields vs. derived topographical attributes in combination with measured soil physical properties, and (ii) quantify the relationships between measured soil physical properties and derived topographical attributes. The dominant soil of the study area was classified as Vaiden soil series (very‐fine, smectitic, thermic Aquic Dystruderts). More than 4500 elevation point data were recorded in a 42‐ha field using a real‐time kinematic‐global positioning system (RTK‐GPS) used in a geographic information system (GIS) to derive topographic (slope, curvature and aspect) and hydrologic attributes (wetness index, flow direction, flow length, flow accumulation, and sediment transport index). Surface (0–17 cm) sand, clay, saturated hydraulic conductivity (Ks), bulk density (ρb), water content at seven equilibrium pressure levels ranging from −0.01 to −1.5 MPa, and 2‐yr cotton lint yield data were measured from sites selected based on classified normalized difference vegetation index (NDVI). Stepwise linear regression indicated that cotton lint yield variability was explained by soil properties (65% in 2001 and 58% in 2002), and topographic and hydrologic attributes (40 and 21%), as well as their combined effects (82 and 72%). Elevation, flow direction, sediment transport index, percentage sand content, and volumetric water content (θv) at −0.001 MPa pressure explained most of the lint yield variation. Overall, statistical analysis indicated that higher elevation areas generally yielded lower (r= −0.50,P< 0.01) and may experience water stress earlier in the season, as compared with lower elevation areas. We expect that once these features are derived and interpreted, they will have a long‐lasting impact on cotton management under dryland conditions.
Soil Temperature Change over Time during Infiltration
Authors: Prunty Lyle , Bell Joel
Published: May 2005

Heat of wetting (HOW) effects release energy during infiltration of water into soil and temperature changes result. We call these changes infiltration transient temperature (ITT). Experiments determined ITT frequently during one‐dimensional infiltration events. We measured ITT in columns of silty clay and loam soils, at several initial water contents, during constant‐rate infiltration. There was a directly increasing, but nonlinear, relationship of ITT to clay content and a decreasing, nonlinear relation to initial water content, ranging from 1°C maximum in loam at 0.04 g g−1 initial water content to 11°C maximum in silty clay at 0.00 g g−1 We compared the resulting experimental temperature profiles to those generated from a one‐dimensional soil water and heat transport model using the relevant initial and boundary conditions. The model‐predicted ITT profiles exhibited the major features of the experimentally measured profiles. Disabling the HOW effect part of the model resulted in a much smaller predicted temperature peak and a subsequent temperature decrease below ambient behind the wetting front. Since experiments and a numerical model have shown ITT to be appreciable, it is important to understand more completely the role of HOW in coupled soil water and heat transport.
Storage‐Induced Changes in Phosphorus Solubility of Air‐Dried Soils
Authors: Turner Benjamin L.
Published: May 2005

Soil is commonly stored in an air‐dried state for extended periods before chemical analysis. The effect of storage on P solubility was assessed by determining NaHCO3–extractable P concentrations in a range of pasture soils from England and Wales (total C = 28.9–80.4 g kg−1, clay = 219–681 g kg−1, pH = 4.4–6.8) immediately following air drying and after 3 yr of storage at ambient laboratory temperature. Following storage, NaHCO3–extractable inorganic P concentrations decreased by between 2 and 60% (mean decrease = 21%), while NaHCO3–extractable organic P concentrations increased by between 48 and 156% (mean increase = 95%). The greatest changes occurred in soils of pH < 5.3. The changes appear to result from the disruption of organic matter coatings on mineral surfaces, continuous solid‐phase diffusion of phosphate into soil particles, and decomposition of microbial cells. The results have important implications for the determination of NaHCO3–extractable P in stored soils and highlight the importance of working with fresh samples to derive information with relevance to field conditions.
Variability and Laboratory Factors Affecting the Sperm Chromatin Structure Assay in Human Semen
Authors: Boe‐Hansen Gry B. , Ersbøll Annette K. , Christensen Preben
Published: May 2005

ABSTRACT: During the past decade, the sperm chromatin structure assay (SCSA) has become an important tool for assessing semen quality in the human andrology laboratory. The SCSA uses the metachromatic properties of the fluorescent dye acridine orange (AO) in combination with flow cytometry to determine the sperm DNA susceptibility to denaturation in situ. The objective of this study was to evaluate laboratory factors affecting the SCSA and the variation between replicates. Semen ejaculates from 3 healthy volunteers were analyzed using the SCSA protocol as described by Evenson and Jost (2000), determining the X‐mean, Y‐mean, DNA fragmentation index (DFI), standard deviation of DFI (SD‐DFI), and high DNA stainability (HDS). In experiment 1, the effects of thawing time, time of day, day, laboratory technician, donor, and incubation period before analysis were investigated. In experiment 2, the effects of sheath fluid, AO equilibration buffer, day, laboratory technician, donor, and incubation period before analysis were investigated. A significant difference was found between the 3 donors with respect to the X‐mean, Y‐mean, DFI, SD‐DFI, and HDS. It was shown that incubation of the semen samples on ice postthaw had a significant effect on the X‐mean, Y‐mean, DFI, and SD‐DFI. The laboratory technician conducting the analysis accounted for up to 15.4% for the variation of the SCSA measurements. The time of day affected the variation for the Y‐mean (23.5% of the total variation of the Y‐mean), and the day affected the variation for the X‐mean (82.8% of the total variation of the X‐mean). Incubation on ice for 5 to 25 minutes postthaw had a significant effect on the DFI and SD‐DFI in both experiments. This study shows that several protocol steps in the SCSA affect the results obtained from the assay. Precise protocol description and standardization of the SCSA are therefore essential to achieve high agreement within and between different laboratories.
Bioactivity of Androgens Within the Testes and Serum of Normal Men
Authors: Jarow Jonathan P. , Wright William W. , Brown Terry R. , Yan Xiaohua , Zirkin Barry R.
Published: May 2005

ABSTRACT: Little is known about how human spermatogenesis is regulated, so it is not surprising that there have been few breakthroughs in the treatment of male infertility resulting from abnormalities of spermatogenesis. Testosterone is the predominant intratesticular steroid in both the rat and man. Previous studies have shown that the testosterone concentration within the rat testis that is required for the quantitative maintenance of spermatogenesis is far higher than the total testosterone concentration in rat blood, indicating that much of the testosterone within the testis might be biologically inactive. In contrast to the rat, little is known about the androgen requirements for human spermatogenesis, in part because, until recently, a minimally invasive method suitable for obtaining intratesticular fluids from the human testis has not been available. Percutaneous aspiration now makes it feasible to do so. A major objective of the present study was to assay the bioactive androgen concentration within the testes of normal, fertile men. Percutaneous aspiration was used to obtain intratesticular fluid from such men, and we adapted a highly sensitive recombinant protein mammalian cell‐based bioassay to measure androgen bioactivity. Total intratesticular testosterone concentration, which we define as immunoreactive testosterone as measured by radioimmunoassay, was well in excess of that in serum (1236 ± 86 nM vs 11.7 ± 0.7 nM). The concentration of bioactive androgens within the normal human testis was found to be about two thirds that of the total testosterone concentration. Interestingly, the concentration of the major, known binding proteins for testosterone within the testis, serum hormone‐binding globulin (SHBG)/ABP (52.4 ± 9.7 nM), was insufficient to account for the difference between total testosterone and bioactive androgens. This indicates that, in addition to its binding to SHBG/ABP, androgens may also be bound by unknown molecules, and that this contributes to reducing androgen bioactivity. These observations could have relevance for understanding the relationship between spermatogenesis and intratesticular androgens in normal men and in men diagnosed with infertility.
Cloning and Sequencing of cDNA Encoding for the Testis‐Specific Fox (Vulpes Vulpes) Sperm Polypeptide Vb of the Cytochrome C Oxidase
Authors: Verdier Yann , Farré Guillaume , Rouet Nelly , Kele Zoltan , Janáky Tamás , Boué Franck
Published: May 2005

ABSTRACT: Identification of fox (Vulpes vulpes) sperm antigens was carried out to assess their interest as a potential target for a contraceptive vaccine. We report here the cloning and sequencing of fSP8, a fox sperm protein of 14.7 kd. fSP8 was isoantigenic in foxes, as it was recognized by sera of both male and female foxes immunized with fox sperm proteins. No glycosylation was detected, on fSP8, as shown both by deglycosylation assay and lectin labeling. To determine the fSP8 sequence, the NH2‐terminal sequence was first obtained, and a piece of cDNA was amplified from testicular RNA by Rapid Amplification of cDNA extremities polymerase chain reaction. This piece was used to screen a cDNA library from fox testis by Southern blot. A sequence of 879 base pairs was obtained, which includes a major open reading frame coding for 128 amino acids. Mass spectrometric analyses have confirmed the position of the open reading frame. Analysis of the predicted amino acids sequence revealed no apparent transmembrane regions. Comparison of the protein sequence with the Prosite database demonstrated a homology with the Zinc binding site of the subunit Vb of the cytochrome c oxidase. On the C‐terminal extremity, fSP8 presents a high homology to the Vb polypeptide of the cytochrome c oxidase from bovine, mouse, and human; however the 34 amino acids on the NH2‐extremity were specific to fSP8. Moreover, it was demonstrated that this sequence was testis‐specific. This could contribute to the antigenicity of this protein. fSP8 is one of the first fox sperm antigens to be cloned and sequenced.
Tadalafil Improved Erectile Function at Twenty‐Four and Thirty‐Six Hours After Dosing in Men With Erectile Dysfunction: US Trial
Authors: Young Jay M. , Feldman Robert A. , Auerbach Stephen M. , Kaufman Joel M. , Garcia Carmen S. , Shen Wei , Murphy Aileen M. , Beasley Charles M. , Hague Jayne A. , Ahuja Sanjeev
Published: May 2005

ABSTRACT: In a previous study assessing tadalafil for the treatment of erectile dysfunction (ED), tadalafil 20 mg was shown to improve erectile function for up to 36 hours vs placebo. This study sought to demonstrate the effectiveness of both 10‐ and 20‐mg tadalafil vs placebo at 2 prespecified assigned times of 24 and 36 hours postdosing. This double‐blind, placebo‐controlled, parallel‐group study randomized 483 men with ED into 6 groups according to a combination of treatment (placebo, tadalafil 10 or 20 mg) and assigned time (24 or 36 hours) for intercourse attempts. Patients were stratified by baseline ED severity based on Erectile Function Domain scores. The study had 4 phases: a 4‐week run‐in (no ED medication taken); a 2‐ to 4‐week equilibration (dosing as needed); a 4‐ to 6‐week assessment; and a 6‐month open‐label extension. During the assessment phase, men took a total of 4 doses of study medication, each dose separated by more than or equal to 7 days. Efficacy was measured as the mean per‐patient percentage of successful intercourse attempts (Sexual Encounter Profile Diary Question 3: SEP3) during the assessment phase. Men taking either 10‐ or 20‐mg tadalafil had a significant increase in SEP3 from baseline scores vs placebo at both 24 hours (P = .038 and <.001 for 10 and 20 mg, respectively) and 36 hours (P < .001 for both doses) postdose. The mean per‐patient percentages of successful intercourse attempts for the 24‐hour time point were 41.8%, 55.8%, and 67.3% for placebo and tadalafil 10 and 20 mg, respectively; for the 36‐hour time point, the mean per‐patient percentages were 32.8%, 56.2%, and 61.9% for placebo and tadalafil 10 and 20 mg, respectively. The most common treatment‐emergent adverse events were headache, back pain, dyspepsia, and nasopharyngitis. Both 10‐ and 20‐mg tadalafil improved erectile function for up to 36 hours postdosing in men with ED of varied severity.
Characterization and Localization of Cysteine‐Rich Secretory Protein 3 (CRISP‐3) in the Human Male Reproductive Tract
Authors: Udby Lene , Bjartell Anders , Malm Johan , Egesten Arne , Lundwall Åke , Cowland Jack B. , Borregaard Niels , Kjeldsen Lars
Published: May 2005

ABSTRACT: Mammalian members of the cysteine‐rich secretory protein (CRISP) family are expressed predominantly in the male reproductive tract and are implicated in the process of reproduction from spermiogenesis, posttesticular sperm maturation, and capacitation to oocyte‐sperm fusion, and possibly also penetration of the zona pellucida. Rodents express only 2 CRISPs (CRISP‐1 and CRISP‐2) in their male reproductive system, whereas humans and horses express an additional third member named CRISP‐3. We have previously demonstrated that this protein is present in human seminal plasma as well as in other exocrine secretions, in blood plasma, and in neutrophilic granulocytes. To characterize the protein in seminal plasma and localize the production of CRISP‐3 in the human male reproductive tract, we performed immunoblotting and enzyme‐linked immunosorbent assay measurements of seminal plasma and immunohistochemistry and in situ hybridization of tissue specimens. We were able to show that human CRISP‐3 is a quantitatively minor seminal plasma protein not associated with prostasomes. Furthermore, CRISP‐3 expression was found in the secretory epithelium throughout the male genital tract, with particularly high expression in the cauda epididymis and ampulla vas deferens. Examination of seminal plasma from vasectomized males indicates that organs downstream of the epididymis are probably the major sources of seminal plasma CRISP‐3.
Idiopathic Infertility: Effect of Palmitoylethanolamide (a Homologue of Anandamide) on Hyperactivated Sperm Cell Motility and Ca2+ Influx
Authors: Ambrosini Annarina , Zolese Giovanna , Ambrosi Simona , Bertoli Enrico , Mantero Franco , Boscaro Marco , Balercia Giancarlo
Published: May 2005

ABSTRACT: The goal of this study was to examine the effect of palmitoylethanolamide (PEA) on the capacitation process and hyperactivated motility (HA) in idiopathic infertile men. Our data show the effect of PEA on the kinematic parameters of sperm cells from idiopathic infertile men during the capacitation of spermatozoa in vitro, both in the presence and absence of 2.5 nM PEA, a molecule physiologically present in human reproductive tracts. Two groups of sperm cells were identified. In group I (36 ± 14 × 106 cells/mL), PEA significantly increased some motility parameters and HA during capacitation. In group II (58 ± 18 × 106 cells/mL), PEA did not significantly modify motility parameters and HA. Fura 2 AM (acetoxymethyl ester derivative of fura 2) measurements demonstrated that PEA increased external Ca2+ influx (which modulates HA) in group I, while no change was measured in group II. In conclusion, our data indicated that PEA modulated certain physiological sperm functions that are involved in fertilization; in particular, we showed that PEA modulated for HA in men with low sperm kinematic parameters.
Strength Measurement of the Sertoli‐Spermatid Junctional Complex
Authors: Wolski Katja M. , Perrault Cecile , Tran‐Son‐Tay Roger , Cameron Don F.
Published: May 2005

ABSTRACT: The Sertoli cell ectoplasmic specialization (ES) is a specialized domain of the calcium‐dependent Sertoli cell‐spermatid junctional complex. Not only is it associated with the mechanical adhesion of the cells, but it also plays a role in the morphogenesis and differentiation of the developing germ cells. Abnormal or absent Sertoli ESs have been associated with step‐8 spermatid sloughing and subsequent oligospermia. With a micropipette pressure transducing system (MPTS) to measure the force needed to detach germ cells from Sertoli cells, this study examined, for the first time, the strength of the junction between Sertoli cells and spermatids and between Sertoli cells and spermatocytes. The mean force needed to detach spermatocytes from Sertoli cells was 5.25 × 10−7 pN, prestep‐8 spermatids from Sertoli cells was 4.73 × 10−7 pN, step‐8 spermatids from Sertoli cells was 8.82 × 10−7 pN, and spermatids plus EDTA was 2.16 × 10−7 pN. These data confirm the hypothesis that step‐8 spermatids are more firmly attached to Sertoli cells than are spermatocytes and pre‐step‐8 spermatids and that calcium chelation reduces binding strength between Sertoli cells and spermatids. The MPTS is a useful tool in studying the various molecular models of the Sertoli‐germ cell junctional strength and the role of reproductive hormones and enzymes in coupling and uncoupling of germ cells from Sertoli cells.
Treatment of Varicocele: Randomized Prospective Study on Open Surgery Versus Tauber Antegrade Sclerotherapy
Authors: Zucchi Alessandro , Mearini Luigi , Mearini Ettore , Costantini Elisabetta , Bini Vittorio , Porena Massimo
Published: May 2005

ABSTRACT: The goal of this randomized prospective study in patients with varicocele was to evaluate the outcome following open surgery with inguinal approach versus antegrade sclerotherapy according to the Tauber procedure. From January 2002 to November 2003, we recruited 64 patients with left varicocele for this study. All patients were clinically examined, before surgery and again 8 months postsurgery, by objective examination, scrotal color Doppler ultrasound, and semen analysis. These patients were randomized in a balanced 4‐block pattern: depending on randomization, the patients underwent open surgery (group A: 32 patients) or antegrade sclerotherapy according to the Tauber procedure (group B: 32 patients). At the current follow‐up, it is possible to evaluate all the patients for whom we have preoperative and postoperative Doppler imaging and semen analysis. An analysis of seminal parameters shows a statistically significant improvement of the rate of fast progressive spermatozoa (P < .05) and reduction in immotile spermatozoa (P < .01) in those patients who underwent sclerotherapy compared to the patients who underwent open surgery. The outcomes of all other parameters (number and morphology) are fully comparable. Operating time is decidedly shorter for antegrade sclerotherapy (P < .01), but there are no significant differences in terms of early or late postoperative complications. It is widely known that varicocele is a condition found in 9% to 23% of the male population around the world; this percentage rises to 40% among infertile males. The treatment of this condition not only resolves clinical symptoms but also stops continuous damage to spermatogenesis, thereby potentially improving fertility. Our experience demonstrates that sclerotherapy (Tauber procedure) combines shorter surgical time and faster recovery of normal daily activities with significant improvement in sperm motility.
Regulatory Cytokine Expression and Interstitial Fluid Formation in the Normal and Inflamed Rat Testis Are Under Leydig Cell Control
Authors: Hedger Mark , Klug Jörg , Fröhlich Suada , Müller Ruth , Meinhardt Andreas
Published: May 2005

ABSTRACT: Leydig cells have been implicated in several inflammation‐related responses of the testis. Specifically, these cells produce the proinflammatory cytokines interleukin‐1 (IL‐1) and IL‐6, stimulate macrophage recruitment, and promote interstitial fluid formation. In addition, the immunoregulatory cytokines macrophage migration inhibitory factor (MIF), transforming growth factor‐β1 (TGFβ1), and interferon‐γ (IFNγ) are constitutively expressed by testicular cells, including the Leydig cells. In the present study, the contribution of the Leydig cell to testicular inflammatory responses was examined in adult male rats treated with the Leydig cell—specific toxin, ethane dimethane sulfonate (EDS). Intratesticular testosterone levels were modulated by subcutaneous testosterone implants. After 10 days, animals received an injection of lipopolysaccharide (LPS) to induce an inflammatory response, or saline alone, and were killed 3 hours later. Both depletion of Leydig cells by EDS and LPS treatment caused a decrease in collected testicular interstitial fluid to about 35% of control levels, but the effects were not additive. Maintenance of intratesticular testosterone reversed the interstitial fluid decline following EDS treatment and partially prevented the LPS‐induced effect. MIF, TGFβ1, and IFNγ were expressed in both the normal and inflamed testis at similar levels. In contrast, EDS treatment caused a significant decline in expression of all 3 cytokines, which was prevented by the testosterone implants. These data indicate that 1) expression of TGFβ1, MIF, and IFNγ in the testis is not dependent on the presence of intact Leydig cells but is under direct testosterone control and 2) the decline in testicular interstitial fluid during inflammation involves the Leydig cells, acting via both androgens and nonandrogenic secretions. These data provide further support for a significant role for the Leydig cell in modulating the testicular response to inflammation.
Paracrine Modulation of Androgen Synthesis in Rat Leydig Cells by Nitric Oxide
Authors: Weissman Ben A. , Niu Enmei , Ge Renshan , Sottas Chantal M. , Holmes Michael , Hutson James C. , Hardy Matthew P.
Published: May 2005

ABSTRACT: The free radical nitric oxide (NO), generated through the oxidation of l‐arginine to l‐citrulline by NO synthases (NOSs), has been shown to inhibit steroidogenic pathways. NOS isoforms are known to be present in rat and human testes. Our study examined the sensitivity of Leydig cells to NO and determined whether NOS activity resides in Leydig cells or in another cell type such as the testicular macrophage. The results showed a low level of l‐[14C]arginine conversion in purified rat Leydig cell homogenates. Administration of the NOS inhibitor L‐NG‐nitro‐arginine methyl ester (L‐NAME), or the calcium chelator ethylenebis (oxyethylenenitrilo)tetraacetic acid (EGTA), had no effect on l‐[14C]citrulline accumulation. Increased intracellular Ca2+ concentrations that were induced by a calcium ionophore, or the addition of luteinizing hormone (LH), failed to affect NO formation in intact cells that were cultured in vitro. Introduction of a high concentration of the NO precursor l‐arginine did not decrease testosterone (T) production, and NOS inhibitors did not increase T biosynthesis. However, exposing Leydig cells to low concentrations of the NO donor S‐nitrosoglutathione (GSNO) induced a dramatic blockade of T production under basal and LH‐stimulated conditions. DNA array assays showed a low level of expression of endothelial NOS (eNOS), while the neuronal and inducible isoforms of NOS (nNOS and iNOS) were below detection levels. Reverse transcriptase‐polymerase chain reaction (RT‐PCR) analyses confirmed these findings and demonstrated the presence of high iNOS messenger RNA (mRNA) levels in activated testicular macrophages that produced large amounts of NO. These data suggest that, while T production in rat Leydig cells is highly sensitive to NO and an endogenous NO‐generating system is not present in these cells, NOS activity is more likely to reside in activated testicular macrophages.
Psychotropic Polypharmacy Among Youths Enrolled in Medicaid
Authors: Chiang Yueh-Yi , Amill-Rosario Alejandro , Tran Phuong , dosReis Susan
Published: February 2024

This cross-sectional study aims to identify temporal changes and characteristics associated with psychotropic polypharmacy among youths aged 17 years or younger who were enrolled in Medicaid in Maryland.
AgAID Institute—AI for agricultural labor and decision support
Authors: Fern Alan , Burnett Margaret , Davidson Joseph , Doppa Janardhan Rao , Pesantez‐Cabrera Paola , Kalyanaraman Ananth
Published: February 2024

The AgAID Institute is a National AI Research Institute focused on developing AI solutions for specialty crop agriculture. Specialty crops include a variety of fruits and vegetables, nut trees, grapes, berries, and different types of horticultural crops. In the United States, the specialty crop industry accounts for a multibillion dollar industry with over 300 crops grown just along the U.S. west coast. Specialty crop agriculture presents several unique challenges: they are labor‐intensive, are easily impacted by weather extremities, and are grown mostly on irrigated lands and hence are dependent on water. The AgAID Institute aims to develop AI solutions to address these challenges, particularly in the face of workforce shortages, water scarcity, and extreme weather events. Addressing this host of challenges requires advancing foundational AI research, including spatio‐temporal system modeling, robot sensing and control, multiscale site‐specific decision support, and designing effective human–AI workflows. This article provides examples of current AgAID efforts and points to open directions to be explored.
An event‐triggered method to distributed filtering for nonlinear multi‐rate systems with random transmission delays
Authors: Li Zehao , Hu Jun , Chen Cai , Yu Hui , Yi Xiaojian
Published: February 2024

In this article, an event‐triggered recursive filtering problem is studied for a class of nonlinear multi‐rate systems (MRSs) with random transmission delays (RTDs). The RTDs are described by utilizing random variables with a known probability distribution and the Kronecker function. To facilitate further study, the MRS is converted into a single‐rate one by adopting an iteration equation approach. To address the challenge of filter design caused by different measurement sampling periods, a modified prediction method of measurements is given. Moreover, an event‐triggered mechanism (ETM) is introduced to regulate the innovation transmission frequency. The objective of the addressed filtering problem is to design a recursive distributed filtering method for MRSs subject to ETM and RTDs, where a minimum upper bound on the filter error covariance is obtained. Moreover, the filter gain matrix is formulated by resorting to the solutions to matrix difference equations. Besides, the boundedness in the mean‐square sense of the filtering error is analyzed and a sufficient condition is provided. Finally, simulations with comparison experiments are presented to demonstrate the effectiveness of the newly proposed theoretical results.
Facile Preparation of TICT@MOF Solids with Unprecedented PL Quantum Yields
Authors: Laha Paltan , Chandra Falguni , Alneyadi Shaikha , Saleh Na'il
Published: February 2024

Luminescent solids exhibit unique optical and electronic properties, and it is important to develop a simple experimental procedure to reduce the mass of weakly emissive hybrid inorganic–organic solids. The instant mixing of (1‐cyano‐2‐[α‐terthiophen‐2‐yl]‐vinyl)carboxylic acid (3TCC) and a metal–organic framework (MOF‐177; ZnO4(BTB)2; BTB = 1,3,5‐benzenetribenzoate) in an organic solvent, followed by evaporation of the solvent, produces solids with distinct photoluminescence (PL) properties, turning over the PL quantum yields (PLQY) of the generated 3TCC@MOF‐177 solids by 2‐ to 40‐fold compared to the 3TCC solution is demonstrated. The new solids are characterized by various methods and optical measurements. Contrarily to the trend in the photophysical results of 3TCC solutions, the anisotropic rotational times of 3TCC@MOF‐177 solids inversely correlate with the corresponding PLQY values depending on the protic solvent used in the initial preparation step in the following order: methanol>ethanol>butanol. This behavior is attributed to the complexation of 3TCC dye with metal clusters within the pores of MOF‐177 and hydrogen bonding of the CN group in the dye with the OH group in the linkers. These factors interplay with the kinetics of dye twisting. These observations reflect the potential of new solid luminescent architectures with remarkable PLQY that can be easily manufactured.
Remote 1,4‐Carbon‐to‐Carbon Boryl Migration: From a Mechanistic Challenge to a Valuable Synthetic Application of Bicycles
Authors: Dominguez‐Molano Paula , Solé‐Daura Albert , Carbó Jorge J. , Fernández Elena
Published: February 2024

The present paper reports a remote carbon‐to‐carbon boryl migration via an intramolecular 1,4‐B/Cu shift, which establishes an in situ stereospecific electrophilic trap on the alkene moiety. The synthetic application is developed to prepare functionalized cyclopentenes by means of a palladium‐catalyzed regioselective intramolecular coupling that completes a strategic cyclopropanation and generates valuable structural bicyclic systems. The mechanism is characterized by DFT (density functional theory) calculations which showed that the 1,4‐migration proceeds through an intramolecular, nucleophilic attack of the copper‐alkyl moiety on the boron atom bonded to the C(sp2), leading to a 5‐membered boracycle structure. The computation of the 1,3‐ and 1,4‐B/Cu shifts is also compared as is the impact of the endo‐ or exocyclic alkene on the reaction kinetics.
Motion Enhanced Multi‐Level Tracker (MEMTrack): A Deep Learning‐Based Approach to Microrobot Tracking in Dense and Low‐Contrast Environments
Authors: Sawhney Medha , Karmarkar Bhas , Leaman Eric J. , Daw Arka , Karpatne Anuj , Behkam Bahareh
Published: February 2024

Tracking microrobots is challenging due to their minute size and high speed. In biomedical applications, this challenge is exacerbated by the dense surrounding environments with feature sizes and shapes comparable to microrobots. Herein, Motion Enhanced Multi‐level Tracker (MEMTrack) is introduced for detecting and tracking microrobots in dense and low‐contrast environments. Informed by the physics of microrobot motion, synthetic motion features for deep learning‐based object detection and a modified Simple Online and Real‐time Tracking (SORT)algorithm with interpolation are used for tracking. MEMTrack is trained and tested using bacterial micromotors in collagen (tissue phantom), achieving precision and recall of 76% and 51%, respectively. Compared to the state‐of‐the‐art baseline models, MEMTrack provides a minimum of 2.6‐fold higher precision with a reasonably high recall. MEMTrack's generalizability to unseen (aqueous) media and its versatility in tracking microrobots of different shapes, sizes, and motion characteristics are shown. Finally, it is shown that MEMTrack localizes objects with a root‐mean‐square error of less than 1.84 μm and quantifies the average speed of all tested systems with no statistically significant difference from the laboriously produced manual tracking data. MEMTrack significantly advances microrobot localization and tracking in dense and low‐contrast settings and can impact fundamental and translational microrobotic research.
One‐pot, Gram‐Scale Synthesis of Calix[5]‐ and Calix[6]furan: Derivatization for Polyketone‐ and Isopyrazole‐based Macrocycles with Conformational Analysis
Authors: Yoneda Tomoki , Sano Taichi , Pati Narendra Nath , Ide Yuki , Inokuma Yasuhide
Published: February 2024

A gram‐scale synthesis of calix[5]‐ and calix[6]furan was achieved by a one‐pot condensation of furan and acetone followed by stepwise separation of calix[n]furans (n=4–6) using size‐selective precipitation procedures. Calix[n]furans were converted to cyclic polyketones and then to ethylene‐bridged cyclic isopyrazoles. The conformational analysis of the cyclic furan, polyketone, and isopyrazole macrocycles was performed based on their single crystal structures, providing important structural insights for intermolecular interactions. The scalable synthetic procedures for larger calix[n]furans and their derivatives would contribute to further coordination and host‐guest chemistry using their cavities.
Tracing synaptic loss in Alzheimer's brain with SV2A PET‐tracer UCB‐J
Authors: Kumar Amit , Scarpa Miriam , Nordberg Agneta
Published: February 2024

INTRODUCTION

Synaptic loss is an early prominent feature of Alzheimer's disease (AD). The recently developed novel synaptic vesicle 2A protein (SV2A) PET‐tracer UCB‐J has shown great promise in tracking synaptic loss in AD. However, there have been discrepancies between the findings and a lack of mechanistic insight.

METHODS

Here we report the first extensive pre‐clinical validation studies for UCB‐J in control (CN; n = 11) and AD (n = 11) brains using a multidimensional approach of post‐mortem brain imaging techniques, radioligand binding, and biochemical studies.

RESULTS AND DISCUSSION

We demonstrate that UCB‐J could target SV2A protein with high specificity and depict synaptic loss at synaptosome levels in AD brain regions compared to CNs. UCB‐J showed highest synaptic loss in AD hippocampus followed in descending order by frontal cortex, temporal cortex, parietal cortex, and cerebellum. 3H‐UCB‐J large brain‐section autoradiography and cellular/subcellular fractions binding studies indicated potential off‐target interaction with phosphorylated tau (p‐tau) species in AD brains, which could have subsequent clinical implications for imaging studies.

Highlights

Synaptic positron emission tomography (PET)–tracer UCB‐J could target synaptic vesicle 2A protein (SV2A) with high specificity in Alzheimer's disease (AD) and control brains.

Synaptic PET‐tracer UCB‐J could depict synaptic loss at synaptosome levels in AD brain regions compared to control.

Potential off‐target interaction of UCB‐J with phosphorylated tau (p‐tau) species at cellular/subcellular levels could have subsequent clinical implications for imaging studies, warranting further investigations.
White and Gray Matter Changes are Associated With Neurocognitive Decline in HIV Infection
Authors: Chien Alice , Wu Tianxia , Lau Chuen‐Yen , Pandya Darshan , Wiebold Amanda , Agan Brian , Snow Joseph , Smith Bryan , Nath Avindra , Nair Govind ,   for the NIH‐DOD NeuroHIV Consortium
Published: February 2024

Objective

To investigate the relationship between neurocognitive deficits and structural changes on brain magnetic resonance imaging in people living with HIV (PLWH) with good virological control on combination antiretroviral therapy, compared with socioeconomically matched control participants recruited from the same communities.

Methods

Brain magnetic resonance imaging scans, and clinical and neuropsychological data were obtained from virologically controlled PLWH (viral load of <50 c/mL and at least 1 year of combination antiretroviral therapy) and socioeconomically matched control participants. Magnetic resonance imaging was carried out on 3 T scanner with 8‐channel head coils and segmented using Classification using Derivative‐based Features. Multiple regression analysis was performed to examine the association between brain volume and various clinical and neuropsychiatric parameters adjusting for age, race, and sex. To evaluate longitudinal changes in brain volumes, a random coefficient model was used to evaluate the changes over time (age) adjusting for sex and race.

Results

The cross‐sectional study included 164 PLWH and 51 controls, and the longitudinal study included 68 PLWH and 20 controls with 2 or more visits (mean 2.2 years, range 0.8–5.1 years). Gray matter (GM) atrophy rate was significantly higher in PLWH compared with control participants, and importantly, the GM and global atrophy was associated with the various neuropsychological domain scores. Higher volume of white matter hyperintensities were associated with increased atherosclerotic cardiovascular disease risk score, and decreased executive functioning and memory domain scores in PLWH.

Interpretation

These findings suggest ongoing neurological damage even in virologically controlled participants, with significant implications for clinical management of PLWH. ANN NEUROL 2024;95:941–950
Versatile Platforms of Microneedle Patches Loaded with Responsive Nanoparticles: Synthesis and Promising Biomedical Applications
Authors: Xie Rixin , Li Wenjing , Shi Kexin , Yang Li , Chen Hongzhong , Jiang Shaoyun , Zeng Xiaowei
Published: February 2024

Microneedle array systems loaded with responsive nanoparticles have received increasing attention due to the advantages of good drug stability, targeting ability, controlled release of drugs, high bioavailability, painlessness, and good patient compliance. Compared with oral drug delivery, microneedle transdermal drug delivery eliminates the need to pass through the gastrointestinal tract and liver, reducing the metabolic consumption of drugs by first‐pass effect. While compared with intravenous drug delivery, microneedle transdermal drug delivery reduces patient discomfort and does not require professional administration. However, there are few review articles on microneedles loaded with responsive nanoparticles. Herein, the current researches on microneedles loaded with specific responsive nanoparticles such as glucose‐responsive, pH‐responsive, enzyme‐responsive, light‐responsive, magnetic‐responsive, ultrasound‐responsive, and multiresponsive, and the biomedical application of these microneedle array systems are summarized. In addition, the challenges and prospects of microneedle strategies loaded with responsive nanoparticles are briefly discussed, which will facilitate the development of such versatile drug‐delivery strategy.
Unveiling pH‐Dependent Adsorption Strength of *CO2− Intermediate over High‐Density Sn Single Atom Catalyst for Acidic CO2‐to‐HCOOH Electroreduction
Authors: Sun Bin , Li Zaiqi , Xiao Difei , Liu Hongli , Song Kepeng , Wang Zeyan , Liu Yuanyuan , Zheng Zhaoke , Wang Peng , Dai Ying , Huang Baibiao , Thomas Arne , Cheng Hefeng
Published: February 2024

The acidic electrochemical CO2 reduction reaction (CO2RR) for direct formic acid (HCOOH) production holds promise in meeting the carbon‐neutral target, yet its performance is hindered by the competing hydrogen evolution reaction (HER). Understanding the adsorption strength of the key intermediates in acidic electrolyte is indispensable to favor CO2RR over HER. In this work, high‐density Sn single atom catalysts (SACs) were prepared and used as catalyst, to reveal the pH‐dependent adsorption strength and coverage of *CO2− intermediatethat enables enhanced acidic CO2RR towards direct HCOOH production. At pH=3, Sn SACs could deliver a high Faradaic efficiency (90.8 %) of HCOOH formation and a corresponding partial current density up to −178.5 mA cm−2. The detailed in situ attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopic studies reveal that a favorable alkaline microenvironment for CO2RR to HCOOH is formed near the surface of Sn SACs, even in the acidic electrolyte. More importantly, the pH‐dependent adsorption strength of *CO2− intermediate is unravelled over the Sn SACs, which in turn affects the competition between HER and CO2RR in acidic electrolyte.
Cr5.7Si2.3P8N24—A Chromium(+IV) Nitridosilicate Phosphate with Amphibole‐Type Structure
Authors: Pointner Monika M. , Fisher Katherine R. , Weidemann Martin , Wolf Florian , Wright Jonathan P. , Bright Eleanor Lawrence , Giacobbe Carlotta , Oeckler Oliver , Schnick Wolfgang
Published: February 2024

The first nitridic analog of an amphibole mineral, the quaternary nitridosilicate phosphate Cr5.7Si2.3P8N24 was synthesized under high‐pressure high‐temperature conditions at 1400 °C and 12 GPa from the binary nitrides Cr2N, Si3N4 and P3N5, using NH4N3 and NH4F as additional nitrogen source and mineralizing agent, respectively. The crystal structure was elucidated by single‐crystal X‐ray diffraction with microfocused synchrotron radiation (C2/m, a=9.6002(19), b=17.107(3), c=4.8530(10) Å, β=109.65(3)°). The elemental composition was analyzed by energy dispersive X‐ray spectroscopy. The structure consists of vertex‐sharing PN4‐tetrahedra forming zweier double chains and edge‐sharing (Si,Cr)‐centered octahedra forming separated ribbons. Atomic resolution scanning transmission electron microscopy shows ordered Si and Cr sites next to a disordered Si/Cr site. Optical spectroscopy indicates a band gap of 2.1 eV. Susceptibility measurements show paramagnetic behavior and support the oxidation state Cr+IV, which is confirmed by EPR. The comprehensive analysis expands the field of Cr−N chemistry and provides access to a nitride analog of one of the most prevalent silicate structures.
Deciphering Oxygen‐Independent Augmented Photodynamic Oncotherapy by Facilitating the Separation of Electron‐Hole Pairs
Authors: Hu Xiaoming , Fang Zhuting , Sun Fengwei , Zhu Caijun , Jia Mingxuan , Miao Xiaofei , Huang Lingting , Hu Wenbo , Fan Quli , Yang Zhen , Huang Wei
Published: February 2024

Developing Type‐I photosensitizers provides an attractive approach to solve the dilemma of inadequate efficacy of photodynamic therapy (PDT) caused by the inherent oxygen consumption of traditional Type‐II PDT and anoxic tumor microenvironment. The challenge for the exploration of Type‐I PSs is to facilitate the electron transfer ability of photosensitization molecules for transforming oxygen or H2O to reactive oxygen species (ROS). Herein, we propose an electronic acceptor‐triggered photoinduced electron transfer (a‐PET) strategy promoting the separation of electron‐hole pairs by marriage of two organic semiconducting molecules of a non‐fullerene scaffold‐based photosensitizer and a perylene diimide that significantly boost the Type‐I PDT pathway to produce plentiful ROS, especially, inducing 3.5‐fold and 2.5‐fold amplification of hydroxyl (OH⋅) and superoxide (O2−⋅) generation. Systematic mechanism exploration reveals that intermolecular electron transfer and intramolecular charge separation after photoirradiation generate a competent production of radical ion pairs that promote the Type‐I PDT process by theoretical calculation and ultrafast femtosecond transient absorption (fs‐TA) spectroscopy. By complementary tumor diagnosis with photoacoustic imaging and second near‐infrared fluorescence imaging, this as‐prepared nanoplatform exhibits fabulous photocytotoxicity in harsh hypoxic conditions and terrific cancer revoked abilities in living mice. We envision that this work will broaden the insight into high‐efficiency Type‐I PDT for cancer phototheranostics.
Surface functionalization of aramid fibers via constructing different zinc oxide nanostructures for improved UV resistance
Authors: Li Na , Zhou Xinyi , Cao Yutong , Yu Junrong , Wang Yan , Hu Zuming
Published: February 2024

Aramid fibers (AFs) with high strength and modulus have a vital application in harsh outdoor bulletproof protection and ship ropes; however, solar radiation, especially ultraviolet (UV) radiation, is one of the main factors for affecting their service life. Herein, different zinc oxide (ZnO) nanostructures were constructed on the surface of AFs by the growth of ZnO nanowires (AF‐ZnO NW) and coating of waterborne polyurethane/ZnO nanoparticles composite emulsion (AF/ZnO), respectively. The surface functionalized AFs exhibited enhanced mechanical properties retention after UV radiation. Nevertheless, the tensile strength of AF‐ZnO NW before UV aging was already lower than the tensile strength of original AFs due to the surface structure damage from chemical grafting modification. The tensile strength and elongation retention rates of AF/ZnO‐5% reached 74.4% and 84.4% after UV exposure for 168 h, respectively, which were much higher than the value of 48.3% and 60.5% of the neat AFs. These results provide an effective and low‐cost strategy for improving the UV‐resistance of advanced high‐performance fibers.
Effects of two antioxidants with different degrees of steric hindrance on the thermal‐oxidative aging properties of ABS resin
Authors: Yao Feng‐Hang , Wang Xiao‐Peng , Chen Jie
Published: February 2024

ABS resin is easily oxidized and deteriorated during use or processing. The addition of antioxidants is an effective method for improving ABS oxidation. The hindered phenol antioxidant DBHMIE and the asymmetrically hindered 245 were added separately or together to ABS; the oxidation induction temperature of ABS increased by 10.6, 12.1 and 14°C, with the addition of DBHMIE, 245 and their combination, respectively, and the initial decomposition temperature T3% increased by 29.7, 16.2 and 51.3°C, respectively. The addition of these two antioxidants to ABS did not greatly affect the mechanical properties of the material, but the impact strength increased by 2.24 kJ/m2 when both antioxidants were added together. During the thermal aging test, the decomposition temperature of the ABS splines prepared with the combined antioxidants increased during the first few cycles. The impact strength of the splines prepared with the combined antioxidants was the highest, with the smallest decrease of only 5.18%. The yellow index of the spline prepared with the combined antioxidants was between those of splines prepared with the antioxidants added alone. The combination of DBHMIE and 245 induced synergistic effects, improved thermal‐oxidative aging resistance, and improved and protected the toughness of ABS resin.
First Nations pre‐LGM ochre processing in Parramatta, NSW, Australia
Authors: Owen Timothy , Munt Simon , Player Sam , Toms Phillip , Wood Jamie
Published: February 2024

Previous archaeological evidence and published analysis has suggested that ochre was first used in the Sydney Basin around 9000 years ago, and that the Parramatta region may not have been occupied by First Nations peoples before ∼14 ka. We present new evidence which firmly places both events before the Last Glacial Maximum (LGM). Multiple ochre fragments, two with microscopically visible evidence of anthropogenic grinding, were recovered from the George Street Gatehouse site within the Parramatta Sand Body (PSB) at Parramatta. The ground ochre was associated with a pit feature buried within the PSB and dated by optically stimulated luminescence (OSL) between ∼35 and 30 ka. This find is the earliest evidence for ochre processing in the Sydney Basin by some 25000 years. A previous model for the region had proposed that occupation prior to and during the LGM was focussed on the Hawkesbury‐Nepean River corridor as a refugium, with only equivocal evidence of occupation prior to ∼14 ka at Parramatta (Williams et al., 2021). We propose that the Parramatta River could also have acted as a refugium for people moving through and occupying the now‐drowned Pleistocene coastal zone; and that those people used ochre in their symbolic expressions.