bluuebunny/crossref_metadata_2025 huggingface dataset:
Bias and standard error for social reciprocity measurements
Authors: Solanas Antonio , Leiva David , Salafranca Lluís
Published: December 2009

The directional consistency and skew‐symmetry statistics have been proposed as global measure of social reciprocity. Although both measures can be useful for quantifying social reciprocity, researchers need to know whether these estimators are biased in order properly to assess descriptive results. That is, if estimators are biased, researchers should compare actual values with expected values under the specified null hypothesis. Furthermore, standard errors are needed to enable suitable assessment of discrepancies between actual and expected values. This paper aims to derive some exact and approximate expressions in order to obtain bias and standard error values for both estimators for round‐robin designs, although the results can also be extended to other reciprocal designs.
Planning health behaviour change: Comparing the behavioural influence of two types of self‐regulatory planning
Authors: van Osch Liesbeth , Reubsaet Astrid , Lechner Lilian , Beenackers Mariëlle , Candel Math , de Vries Hein
Published: December 2009

Objectives

Recent efforts in health psychology to bridge the gap between individuals' intentions and behaviour have centered on the influence of planning strategies. This study investigated the impact of two commonly used types of self‐regulatory planning in the prediction of health promoting behaviour.

Design

This study employed a prospective longitudinal design. Three measurements were implemented in order to assess associations between various socio‐cognitive determinants, planning, and health behaviour.

Methods

Structural equation modelling (N=572) was used to compare the value of preparatory planning, i.e. the planning of strategies and preparatory actions towards a goal behaviour, and implemental planning, i.e. the planning of when, where, and how to perform a goal behaviour, in the prediction of fruit consumption.

Results

Both preparatory planning (ß=0.21; p<.001) and implemental planning (ß=0.13; p<.01) were significant predictors of fruit consumption, over and above the influence of motivational factors. Comparison of differences in explained variance (ΔR2) indicated that the contribution of preparatory planning was larger than that of implemental planning (z=2.19; p<.05). Implemental planning did not contribute to the prediction of fruit consumption over and above the influence of preparatory planning when tested simultaneously.

Conclusions

The results provide a first indication that the planning of strategic preparatory actions may be more influential in predicting health behaviour than implemental planning, focusing on when, where, and how to enact goal‐directed behaviour. Implications of the results and suggestions for future research are outlined.
The Experiences and Needs of People Who Cease Driving After Stroke
Authors: Liddle Jacki , Turpin Merrill , McKenna Kryss , Kubus Tara , Lambley Sonia , McCaffrey Katherine
Published: December 2009

Driving cessation can result in a range of negative consequences, including impacts on identity, mood, and life satisfaction. The aims of this study were to explore the needs and experiences of people who cease driving following a stroke, with the aim of informing clinical practice.Method:Using a qualitative phenomenological approach, semi-structured, audiotaped interviews were conducted to gain an understanding of the needs and experiences of 24 participants (17 male, 7 female, mean of 5.5 years post driving cessation) who had ceased driving following a stroke.Results:After constant comparative analysis, four themes emerged from the data. These were labelled ‘life without driving’, ‘key times of need’, ‘alternatives and other ways’, and ‘carer support and assistance’. Most participants found stopping driving after their stroke to be a sudden, unexpected and intense experience and raised issues, including the loss of numerous life-roles, challenges associated with arranging alternative transport, and reliance on carers and the need for more information throughout the process.Conclusion:Individuals who cease driving following a stroke have unmet needs and difficult experiences throughout the process. Key times of particular need have been identified in this study. These findings have important implications for health professionals that include providing more information and support with driving cessation and alternatives to driving.
Supporting the Needs of Young Adults With Acquired Brain Injury During Transition From Hospital to Home: The Queensland Service Provider Perspective
Authors: Cornwell Petrea , Fleming Jennifer , Fisher Annette , Kendall Melissa , Ownsworth Tamara , Turner Benjamin
Published: December 2009

Objective: To explore the availability and perceived adequacy of service support for younger people with ABI and their families in Queensland during the transition phase from the perspective of service providers. Research Design: A qualitative research design utilising survey-based open-ended questioning. Methods and Procedures: Participants were service provider organisations in Queensland for younger people with aquired brain injury (ABI). A two-part survey was developed for the purpose of the study. The first part of the survey obtained general information regarding client base and service characteristics for each organisation, while the second part was designed to identify gaps in, and barriers and facilitators to service provision. Snowballing recruitment was used with the initial seed point an existing Brain Injury Network. Results: A response rate of 20% was obtained with a total of 12 surveys returned representing seven service providers. Services currently available included rehabilitation, consultancy, education and training, and practical and emotional supports. Existing gaps in, and barriers to service provision were clustered under three key themes: service infrastructure, transition support, and transition context. Some of the facilitators to service provision identified included interagency linkages and financial compensation for injury. Conclusions: Gaps in, and barriers to service provision during the transition phase were identified that could be utilised to develop models of service delivery to improve short- and long-term outcomes for younger people with ABI.
A non-genomic signaling pathway shut down by mating changes the estradiol-induced gene expression profile in the rat oviduct
Authors: Parada-Bustamante Alexis , Orihuela Pedro A , Ríos Mariana , Cuevas Catherina A , Oróstica Maria Lorena , Velásquez Luis A , Villalón Manuel J , Croxatto Horacio B
Published: December 2009

Estradiol (E2) accelerates oviductal egg transport through intraoviductal non-genomic pathways in unmated rats and through genomic pathways in mated rats. This shift in pathways has been designated as intracellular path shifting (IPS), and represents a novel and hitherto unrecognized effect of mating on the female reproductive tract. We had reported previously that IPS involves shutting down the E2non-genomic pathway up- and downstream of 2-methoxyestradiol. Here, we evaluated whether IPS involves changes in the genomic pathway too. Using microarray analysis, we found that a common group of genes changed its expression in response to E2in unmated and mated rats, indicating that an E2genomic signaling pathway is present before and after mating; however, a group of genes decreased its expression only in mated rats and another group of genes increased its expression only in unmated rats. We evaluated the possibility that this difference is a consequence of an E2non-genomic signaling pathway present in unmated rats, but not in mated rats. Mating shuts down this E2non-genomic signaling pathway up- and downstream of cAMP production. TheStarlevel is increased by E2in unmated rats, but not in mated rats. This is blocked by the antagonist of estrogen receptor ICI 182 780, the adenylyl cyclase inhibitor SQ 22536, and the catechol-O-methyltransferase inhibitor, OR 486. These results indicate that the E2-induced gene expression profile in the rat oviduct differs before and after mating, and this difference is probably mediated by an E2non-genomic signaling pathway operating on gene expression only in unmated rats.
Influence of leptin on in vitro maturation and steroidogenic secretion of cumulus–oocyte complexes through JAK2/STAT3 and MEK 1/2 pathways in the rabbit model
Authors: Arias-Álvarez M , García-García R M , Torres-Rovira L , González-Bulnes A , Rebollar P G , Lorenzo P L
Published: December 2009

Extreme body mass indexes may impair reproductive outcome in assisted reproductive technologies. Leptin reflects the amount of body fat and could act as a modulator of oocyte quality through activation of specific transcription factors. The aim of this work was to establish whether: 1) leptin influences meiotic and cytoplasmic oocyte maturation; 2) STAT3 and MAPK mediate the effects of leptin and 3) leptin modulates steroid secretion by cumulus–oocyte complexes (COC) duringin vitromaturation (IVM). We confirmed immunolocalisation of leptin receptor in oocytes, cumulus/granulosa cells during the peri-ovulatory period. The confocal study showed that COC supplemented with 1, 10 and 100 ng/ml leptin had a significantly higher metaphase II (MII) percentage than those IVM without leptin (P<0.05) and a similar MII index compared to the group supplemented with 10% FCS. Leptin did not increase the percentage of cytoplasmically matured oocytes in terms of cortical granule migration rate, whereas a significantly higher index was found in the FCS group (P<0.001). Oestradiol concentrations in spent media were higher in the FCS group compared to other treatments (P<0.001). Leptin-stimulated nuclear oocyte maturation was significantly impaired when leptin-induced JAK2/STAT3 and MEK 1/2 activation was suppressed by the inhibitors (P<0.001). Steroid secretion of COC was not affected by leptin activation of JAK2/STAT3 or MEK 1/2 pathways. In conclusion, JAK2/STAT3 and MEK 1/2 pathways mediate the enhancement of nuclear oocyte maturation by leptin; however, neither cytoplasmic oocyte maturation nor steroidogenic response of COC were improved in the present rabbit model.
Preparation and characterization of heterojunction semiconductor YFeO3/TiO2 with an enhanced photocatalytic activity
Authors: Lū Xiaomeng , Liu Jun , Zhu Jianjun , Jiang Deli , Xie Jimin
Published: December 2009

YFeO3/TiO2 heterojunction semiconductors were prepared by the milling–annealing method. Effects of structure and surface phase by annealing temperature and TiO2 weight content were investigated. The physical and photophysical properties of heterojunction semiconductors were characterized by x-ray diffraction (XRD), UV-visible diffraction (UV-vis/DRS), and x-ray photoelectron spectroscopy (XPS), N2 adsorption. YFeO3 is presented as p-type semiconductor and disperses on the surface of n-type TiO2 to constitute a heterojunction composite. Results show that the presence of p–n junction not only has visible light harvesting but potential force for hole–electron pair separation. A preliminary investigation of photodegradation effect on Orange II showed that YFeO3/TiO2 heterojunction semiconductors exhibited better photocatalytic properties than the single phase of YFeO3 or TiO2. The ideal heterojunction semiconductor composition was ω (TiO2) = 0.9 sample annealed at 600 °C. The mechanism of the electric-field-driven electron–hole separation initiated by the chemically bonded p–n heterojunction and enhanced photocatalytic activity were discussed.
Highly efficient H2 evolution over ZnO-ZnS-CdS heterostructures from an aqueous solution containing SO32- and S2- ions
Authors: Wang Xuewen , Liu Gang , Chen Zhi-Gang , Li Feng , Lu Gao Qing , Cheng Hui-Ming
Published: December 2009

ZnO-ZnS-CdS heterostructure photocatalysts for water splitting were designed and prepared by a wet chemistry method. It was found that ZnO-ZnS-CdS heterostructures are highly active photocatalysts for H2 evolution under simulated solar light irradiation in an aqueous solution containing SO32- and S2- ions as sacrificial reagents. H2 evolution with (ZnO)2-(ZnS)1-(CdS)1 heterostructure reaches up to 2790 μmol h−1 g−1. The photoexcited electrons in the ZnO-ZnS-CdS heterostructures have a much longer lifetime (>225 ns) than that of the sole ZnO, ZnS, and CdS (<65 ns). The favorable interface processes of the heterostructures make a significant contribution to high photocatalytic H2 evolution rate.
Shear strengthening of reinforced concrete beams with CFRP
Authors: Bukhari I.A. , Vollum R.L. , Ahmad S. , Sagaseta J.
Published: December 2009

The current paper reviews existing design guidelines for strengthening beams in shear with carbon fibre reinforced polymer (CFRP) sheets and proposes a modification to Concrete Society Technical Report TR55. It goes on to present the results of an experimental programme which evaluated the contribution of CFRP sheets towards the shear strength of continuous reinforced concrete (RC) beams. A total of seven, two-span concrete continuous beams with rectangular cross-sections were tested. The control beam was not strengthened, and the remaining six were strengthened with different arrangements of CFRP sheets. The experimental results show that the shear strength of the beams was significantly increased by the CFRP sheet and that it is beneficial to orientate the FRP at 45° to the axis of the beam. The shear strength of FRP strengthened beams is usually calculated by adding individual components of shear resistance from the concrete, steel stirrups and FRP. The superposition method of design is replaced in Eurocode 2 by the variable angle truss model in which all the shear is assumed to be resisted by the truss mechanism. The current paper proposes a methodology for strengthening beams with FRP that is consistent with Eurocode 2.
On Parameter Estimation in Hierarchical Credibility
Authors: Belhadj Hassine , Goulet Vincent , Ouellet Tommy
Published: December 2009

One can find in the literature three main sets of estimators for the variance components in the hierarchical credibility model. This paper presents these estimators in a unified notation, studies some of their properties important for numerical evaluation and compares their relative performance by simulation. The paper also demonstrates how function cm of the R package actuar can be used to fit hierarchical models to insurance data.
Multi-Level Risk Aggregation
Authors: Filipović Damir
Published: December 2009

In this paper we compare the current Solvency II standard and a genuine bottom-up approach to risk aggregation. This is understood to be essential for developing a deeper insight into the possible differences between the diversification assumptions between the standard approach and internal models.
A Note on Nonparametric Estimation of the CTE
Authors: Ko Bangwon , Russo Ralph P. , Shyamalkumar Nariankadu D.
Published: December 2009

The α-level Conditional Tail Expectation (CTE) of a continuous random variable X is defined as its conditional expectation given the event {X > qα} where qα represents its α-level quantile. It is well known that the empirical CTE (the average of the n (1 – α) largest order statistics in a sample of size n) is a negatively biased estimator of the CTE. This bias vanishes as the sample size increases, but in small samples can be significant. In this article it is shown that an unbiased nonparametric estimator of the CTE does not exist. In addition, the asymptotic behavior of the bias of the empirical CTE is studied, and a closed form expression for its first order term is derived. This expression facilitates the study of the behavior of the empirical CTE with respect to the underlying distribution, and suggests an alternative (to the bootstrap) approach to bias correction. The performance of the resulting estimator is assessed via simulation.
Releasing Phosphorus from Calcium for Struvite Fertilizer Production from Anaerobically Digested Dairy Effluent
Authors: Zhang Tianxi , Bowers Keith E. , Harrison Joseph H. , Chen Shulin
Published: December 2009

Being a non‐renewable resource and a source of potential water pollution, phosphorus could be recovered from animal manure in the form of struvite (MgNH4PO4·6H2O) to be used as a slow‐release fertilizer. It was found recently that the majority of phosphorus in anaerobically digested dairy effluent is tied up in a fine suspended calcium‐phosphate solid, thus becoming unavailable for struvite formation. Acidification and use of a chelating agent were investigated for converting the calcium‐associated phosphorus in the digested effluent to dissolved phosphate ions, so that struvite can be produced. The results demonstrated that the phosphorus in the effluent was released into the solution by lowering the pH. In addition, the phosphorus concentration in the solution increased significantly with increased ethylenediaminetetraacetic acid (EDTA) concentration, as EDTA has a high stability constant with calcium. Most of the phosphorus (91%) was released into the solution after adding EDTA. Further, the freed phosphorus ion precipitated out as struvite provided that sufficient magnesium ions (Mg2+) were present in the solution. Furthermore, the phase structure of the solid precipitate obtained from the EDTA treatment matched well with standard struvite, based on the data from X‐ray diffraction analysis. These results provide methods for altering the forms of phosphorus for the design and application of phosphorus‐removal technologies for dairy wastewater management.
Studies on the Integration of Nanofiltration and Soil Treatment for Municipal Effluent Reclamation as a Groundwater Supplement
Authors: Linlin Wu , Xuan Zhao , Meng Zhang
Published: December 2009

Water shortage leads to increasing attention to artificial groundwater recharge by reclaimed water. An injection well is the most common recharge approach. In this paper, a new kind of integrated technology—short‐term vadose soil treatment followed by nanofiltration—is recommended as pretreatment for artificial groundwater recharge by an injection well. Laboratory‐scale experiments demonstrate that the short‐term vadose soil can remove approximately 30% of the total dissolved organic carbon (DOC) content and 40% of dissolved organic matter with a molecular weight less than 1 kDa. As a compensatory process of soil treatment, nanofiltration offers a favorable desalination and additional organics removal. The removal efficiencies for total dissolved solids and conductivity amount to 45 and 48%, respectively. The residual DOC in the final effluent is below 1.0 mg/L. In addition, short‐term vadose soil offers effective elimination of aromatic protein‐like and polysaccharide‐like substances, which are detected as components of the membrane foulant.
Synthesis and photophysical properties of novel thiophenylacrylonitrile derivatives containing a triphenylamine moiety
Authors: Fang Haiyan , Yu Mingxin
Published: December 2009

( Z)-2-(4-Halogenophenyl)-3-(thiophen-3-yl)acrylonitrile can be prepared by condensation of thiophene-3-carbaldehyde with arylacetonitrile halides in the presence of catalytic amounts of NaOCH3 at room temperature. Secondary arylamines reacted with ( Z)-2-(4-halogenophenyl)-3-(thiophen-3-yl)acrylonitriles to afford thiophenylacrylonitrile derivatives containing a triphenylamine moiety on catalysis by Pd(OAc)2/P( o-tolyl)3 at 120°C in toluene. The UV-Vis absorption and photoluminescent (PL) spectra of the products in CH2Cl2were investigated.
Mild and ligand-free palladium-catalysed Suzuki–Miyaura cross-couplings in aqueous two-phase system
Authors: Guo Sheng-Rong , Yuan Yan-Qin
Published: December 2009

Pd(OAc)2 combined with an ethanol/K2HPO4 aqueous two-phase system was developed as an inexpensive and efficient catalytic system for Suzuki–Miyaura cross-coupling. The couplings between aryl iodides and arylboronic acids proceeded smoothly in moderate to excellent yields at 60°C in the aqueous two-phase system, and aryl bromides required a higher reaction temperature (reflux at about 80°C) to improve the yield.
CXCL 9 and CXCL 10 as Sensitive Markers of Disease Activity in Patients with Rheumatoid Arthritis
Authors: KUAN WOON PANG , TAM LAI-SHAN , WONG CHUN-KWOK , KO FANNY W.S. , LI TENA , ZHU TRACY , LI EDMUND K.
Published: December 2009

Objective.

To assess whether serum levels of CC and CXC chemokines correlate with disease activity in patients with rheumatoid arthritis (RA), and to determine whether these effects predict clinical response.

Methods.

Serum levels of the chemokines CC (CCL2, CCL5) and CXC (CXCL8, CXCL9, CXCL10) were quantified at baseline and after 12 weeks of treatment with disease-modifying antirheumatic drugs or biologic agents in 28 patients using flow cytometry. Serum from 40 healthy individuals was collected for comparison at baseline. Response to treatment was classified according to the European League Against Rheumatism (EULAR) response criteria. Remission of disease was defined as a Disease Activity Score < 2.6.

Results.

The baseline serum concentrations of CC and CXC chemokines were significantly elevated in patients with active RA compared to healthy controls (p < 0.05) except for CCL2. Significant improvement in all disease activity measurements was observed after 12 weeks of treatment. Seventeen (60.7%) patients achieved good to moderate response based on the EULAR response criteria, and 5 (17.9%) patients achieved remission. The improvement in clinical activity in patients with RA was accompanied by a significant reduction in the serum concentration of CXCL9 and CXCL10 (p < 0.001). A significant reduction in the serum level of CXCL10 was also observed in the group that achieved EULAR response. Serum concentration of CCL5 remained significantly elevated in patients with RA (n = 5) who achieved remission compared to the healthy controls (p < 0.05).

Conclusion.

Serum concentration of CXCL9 and CXCL10 may serve as sensitive biomarkers for disease activity in patients with RA.
Human Embryonic Stem Cells Suppress T Cell Responses via Arginase I-Dependent Mechanism
Authors: Yachimovich-Cohen Nurit , Even-Ram Sharona , Shufaro Yoel , Rachmilewitz Jacob , Reubinoff Benjamin
Published: December 2009

Human embryonic stem cells (hESCs) can proliferate extensively in culture and give rise to progeny of the three germ layers. Several reports suggested that mouse and hESCs may attenuate immune responses. In this study, we focused on the mechanism by which hESCs inhibit T cell responses. Using coculture experiments, we demonstrate that hESCs inhibit cytokine secretion and T cell proliferation in response to potent T cell activators. Furthermore, we show that hESCs downmodulate the TCR-associated CD3-ζ chain. These effects are maintained when hESCs are replaced by their conditioned media and can be restored by the addition of l-arginine to hESC-conditioned media or by treatment of hESCs with a specific arginase inhibitor. Moreover, we show arginase-I expression and activity in hESCs. We further demonstrate that mouse ESCs (mESCs) similarly inhibit T cell activation via arginase I, suggesting an evolutionary conserved mechanism of T cell suppression by ESCs. In addition, we demonstrate that arginase I expression is not limited to ESCs in culture, but can also be detected in the inner cell mass and the trophectoderm of preimplantation mouse embryos and hESC-derived trophectoderm cells. Finally, T cells infiltrating ESC-derived teratomas have significantly lower levels of CD3-ζ chain. Collectively, the data indicate a role for ESC-arginase I activity in the attenuation of T cell activation.
The conics of Lucas' configuration
Authors: Herrera Gómez Blas
Published: December 2009

Der vorliegende Beitrag ist eine Variation zur sogenannten Lucas-Konfiguration. Diese ist beschrieben durch ein Dreieck und die ihm einbeschriebenen drei Quadrate, deren eine Seite jeweils auf einer der Dreiecksseiten liegt. Der Autor beweist nun das bemerkenswerte Resultat, dass die zwölf Eckpunkte der drei Quadrate in zwei Klassen mit je sechs Punkten zerfallen, so dass die Punkte beider Klassen jeweils einen Kegelschnitt beschreiben. Eine Klasse beschreibt dabei sogar eine Ellipse.
Multidrug-Resistant “Super Gonorrhea” Rallies Multipronged Effort
Authors: Landhuis Esther Wei-Yun
Published: May 2024

This Medical News article discusses approaches to slow the spread of antimicrobial resistance in Neisseria gonorrhoeae.
US Hospital Service Availability and New 340B Program Participation
Authors: Owsley Kelsey M. , Hasnain-Wynia Romana , Rooks Ronica N. , Tung Gregory J. , Mays Glen P. , Lindrooth Richard C.
Published: May 2024

Importance

The US 340B Drug Pricing Program enables eligible hospitals to receive substantial discounts on outpatient drugs to improve hospitals’ financial sustainability and maintain access to care for patients who have low income and/or are uninsured. However, it is unclear whether hospitals use program savings to subsidize access as intended.

Objective

To evaluate whether the 340B program is associated with improvements in access to hospital-based services and to test whether the association varies by hospital ownership.

Design, Setting, and Participants

Difference-in-differences and cohort analysis from 2010 to 2019. Never and newly participating 340B general, acute, nonfederal hospitals in the US using data from the American Hospital Association’s Annual Survey of Hospitals merged with hospital and market characteristics. Data were analyzed from January 1, 2023, to January 31, 2024.

Exposures

New enrollment in 340B between 2012 and 2018.

Main Outcomes and Measures

Total number of unprofitable service lines, ie, substance use, psychiatric (inpatient and outpatient), burn clinic, and obstetrics services; and profitable services, ie, cardiac surgery and orthopedic, oncologic, neurologic, and neonatal intensive services.

Results

The study sample comprised a total of 2152 hospitals, 1074 newly participating and 1078 not participating in the 340B program. Participating hospitals were more likely than nonparticipating hospitals to be critical access and teaching hospitals, have higher Medicaid shares, and be located in rural areas and in Medicaid expansion states. At public hospitals, participation in the 340B program was associated with a significant increase in total unprofitable services (0.21; 95% CI, 0.04 to 0.38; P = .02) and marginal increases in substance use (5.4 percentage points [pp]; 95% CI, –0.8 pp to 11.6 pp; P = .09) and inpatient psychiatric (6.5 pp; 95% CI, –0.7 pp to 13.7 pp; P = .09) services. Among nonprofit hospitals, there was no significant association between 340B and service offerings (profitable and unprofitable) except for an increase in oncologic services (2.5 pp; 95% CI, 0.0 pp to 5.0 pp; P = .05).

Conclusions and Relevance

The finding of the cohort study indicate that participation in the 340B program was associated with an increase in unprofitable services among newly participating public hospitals. Nonprofit hospitals were largely unaffected. These findings suggest that public hospitals responded to 340B savings by improving patient access, whereas nonprofits did not. This heterogeneous response should be considered when evaluating the eligibility criteria for the 340B program and how it affects social welfare.
Public Restroom Access and Mental Health Among Gender-Minoritized Individuals in China
Authors: Wang Yuanyuan , Liu Dongyu , Han Meng , Li Jiaqi , Yu Hui
Published: May 2024

This cross-sectional study assesses the adequacy of gender-neutral public restrooms and examines the association of public restroom–related stress with mental health among gender-diverse individuals in China.
Prostate‐Specific Membrane Antigen Targeted StarPEG Nanocarrier for Imaging and Therapy of Prostate Cancer
Authors: Meher Niranjan , Ashley Gary W. , Bobba Kondapa Naidu , Wadhwa Anju , Bidkar Anil P. , Dasari Chandrashekhar , Mu Changhua , Sankaranarayanan Ramya Ambur , Serrano Juan A. Camara , Raveendran Athira , Bulkley David P. , Aggarwal Rahul , Greenland Nancy Y. , Oskowitz Adam , Wilson David M. , Seo Youngho , Santi Daniel V. , VanBrocklin Henry F. , Flavell Robert R.
Published: May 2024

The tumor uptake of large non‐targeted nanocarriers primarily occurs through passive extravasation, known as the enhanced permeability and retention (EPR) effect. Prior studies demonstrated improved tumor uptake and retention of 4‐arm 40 kDa star polyethylene glycol (StarPEG) polymers for cancer imaging by adding prostate‐specific membrane antigen (PSMA) targeting small molecule ligands. To test PSMA‐targeted delivery and therapeutic efficacy, StarPEG nanodrugs with/without three copies of PSMA‐targeting ligands, ACUPA, are designed and synthesized. For single‐photon emission computed tomography (SPECT) imaging and therapy, each nanocarrier is labeled with 177Lu using DOTA radiometal chelator. The radiolabeled nanodrugs, [177Lu]PEG‐(DOTA)1 and [177Lu]PEG‐(DOTA)1(ACUPA)3, are evaluated in vitro and in vivo using PSMA+ PC3‐Pip and/or PSMA– PC3‐Flu cell lines, subcutaneous xenografts and disseminated metastatic models. The nanocarriers are efficiently radiolabeled with 177Lu with molar activities 10.8–15.8 MBq/nmol. Besides excellent in vitro PSMA binding affinity (kD = 51.7 nM), the targeted nanocarrier, [177Lu]PEG‐(DOTA)1(ACUPA)3, demonstrated excellent in vivo SPECT imaging contrast with 21.3% ID/g PC3‐Pip tumors uptake at 192 h. Single doses of 18.5 MBq [177Lu]PEG‐(DOTA)1(ACUPA)3 showed complete resolution of the PC3‐Pip xenografts observed up to 138 days. Along with PSMA‐targeted excellent imaging contrast, these results demonstrated high treatment efficacy of [177Lu]PEG‐(DOTA)1(ACUPA)3 for prostate cancer, with potential for clinical translation.
Surface Reconstruction for Efficient NiOx‐Based Inverted Perovskite Solar Cells
Authors: Yan Nan , Cao Yang , Jin Zhiwen , Liu Yucheng , Liu Shengzhong (Frank) , Fang Zhimin , Feng Jiangshan
Published: May 2024

Functional agents are verified to efficiently enhance device performance of perovskite solar cells (PSCs) through surface engineering. However, the influence of intrinsic characteristics of molecules on final device performance is overlooked. Here, a surface reconstruction strategy is developed to enhance the efficiency of inverted PSCs by mitigating the adverse effects of lead chelation (LC) molecules. Bathocuproine (BCP) is chosen as the representative of LC molecules for its easy accessibility and outstanding optoelectronic properties. During this strategy, BCP molecules on perovskite surface are first dissolved in solvents and then captured specially by undercoordinated Pb2+ ions, preventing adverse n‐type doping by the molecules themselves. In this case, the BCP molecule exhibits outstanding passivation effect on perovskite surface, which leads to an obviously increased open‐circuit voltage (VOC). Therefore, a record power conversion efficiency of 25.64% for NiOx‐based inverted PSCs is achieved, maintaining over 80% of initial efficiency after exposure to ambient condition for ≈1500 h.
Effects of Vanadium Doping on the Optical Response and Electronic Structure of WS2 Monolayers
Authors: Sousa Frederico B. , Zheng Boyang , Liu Mingzu , Resende Geovani C. , Zhou Da , Pimenta Marcos A. , Terrones Mauricio , Crespi Vincent H. , Malard Leandro M.
Published: May 2024

2D dilute magnetic semiconductors have been recently reported in transition metal dichalcogenides doped with spin‐polarized transition metal atoms, for example vanadium‐doped WS2 monolayers, which exhibit room‐temperature ferromagnetic ordering. However, a broadband characterization of the electronic band structure of these doped WS2 monolayers and its dependence on vanadium concentration is still lacking. Therefore, power‐dependent photoluminescence, resonant four‐wave mixing, and differential reflectance spectroscopies are performed here to study optical transitions close to the A exciton energy of vanadium‐doped WS2 monolayers at three different doping levels. Instead of a single A exciton peak, vanadium‐doped samples exhibit two photoluminescence peaks associated with transitions from a donor‐like level and the conduction band minima. Moreover, resonant Raman and second‐harmonic generation experiments reveal a blueshift in the B exciton energy but no energy change in the C exciton after vanadium doping. Density functional theory calculations show that the band structure is sensitive to the Hubbard U correction for vanadium, and several scenarios are proposed to explain the two photoluminescence peaks around the A exciton energy region. This work provides the first broadband optical characterization of these 2D dilute magnetic semiconductors, shedding light on the novel and tunable electronic features of V‐doped WS2 monolayers.
Water‐Assisted Synthesis of Layer‐Controlled CsPbBr3 Nanoplates Spontaneously Encapsulated in PbBr(OH)
Authors: Lian Zhen‐Dong , Wang Bo , Wu Zhi‐Sheng , Lin Hao , Ding Ting , Wang Jin‐Xiao , Zhang Liang‐Xing , Xu Jin‐Cheng , Xiao Peng , Xu Hua , Wang Shuang‐Peng , Ng Kar Wei
Published: May 2024

CsPbBr3 nanoplates (NPs) have shown great potential in diverse optoelectronic applications. Despite the wonderful luminescence properties, the inherent instability of these NPs hinders their use in practical situations. Herein, a facile water‐assisted strategy is reported to synthesize highly stable blue emission CsPbBr3 NPs encapsulated in PbBr(OH). The introduction of water directly into the reaction mixture is pivotal, as it triggers the transformation of bulk CsPbBr3 nanocubes into 2‐D CsPbBr3 NPs within the PbBr(OH) matrix, resulting in the formation of CsPbBr3@PbBr(OH) microbricks. Remarkably, the water content in the reaction mixture allows the control of the number of perovskite layers in the NPs, thus enabling the emission color to be tuned from deep blue to green. The unconventional approach presented herein not only offers a cost‐effective pathway to synthesize blue‐emitting perovskites which are highly stable in a wide variety of polar and non‐polar solvents, but also holds immense potential for propelling the advancement of high‐performance LEDs and other optoelectronic devices. The findings underscore the significance of water in dictating the growth dynamics and emission characteristics of perovskite NPs, paving the way for their practical application.
Diffuse optical tomography for mapping cerebral hemodynamics and functional connectivity in delirium
Authors: Jiang Shixie , Huang Jingyu , Yang Hao , Czuma Richard , Farley Lauren , Cohen‐Oram Alexis , Hartney Kimberly , Chechotka Kristina , Kozel F. Andrew , Jiang Huabei
Published: May 2024

INTRODUCTION

Delirium is associated with mortality and new onset dementia, yet the underlying pathophysiology remains poorly understood. Development of imaging biomarkers has been difficult given the challenging nature of imaging delirious patients. Diffuse optical tomography (DOT) offers a promising approach for investigating delirium given its portability and three‐dimensional capabilities.

METHODS

Twenty‐five delirious and matched non‐delirious patients (n = 50) were examined using DOT, comparing cerebral oxygenation and functional connectivity in the prefrontal cortex during and after an episode of delirium.

RESULTS

Total hemoglobin values were significantly decreased in the delirium group, even after delirium resolution. Functional connectivity between the dorsolateral prefrontal cortex and dorsomedial prefrontal cortex was strengthened post‐resolution compared to during an episode; however, this relationship was still significantly weaker compared to controls.

DISCUSSION

These findings highlight DOT's potential as an imaging biomarker to measure impaired cerebral oxygenation and functional dysconnectivity during and after delirium. Future studies should focus on the role of cerebral oxygenation in delirium pathogenesis and exploring the etiological link between delirium and dementias.

Highlights

We developed a portable diffuse optical tomography (DOT) system for bedside three‐dimensional functional neuroimaging to study delirium in the hospital.

We implemented a novel DOT task‐focused seed‐based correlation analysis.

DOT revealed decreased cerebral oxygenation and functional connectivity strength in the delirium group, even after resolution of delirium.
A Stretchable and Tough Graphene Film Enabled by Mechanical Bond
Authors: Wang Chunyu , Gao Boyue , Fang Fuyi , Qi Wenhao , Yan Ge , Zhao Jun , Wang Wenbin , Bai Ruixue , Zhang Zhaoming , Zhang Zhitao , Zhang Wenming , Yan Xuzhou
Published: May 2024

The pursuit of fabricating high‐performance graphene films has aroused considerable attention due to their potential for practical applications. However, developing both stretchable and tough graphene films remains a formidable challenge. To address this issue, we herein introduce mechanical bond to comprehensively improve the mechanical properties of graphene films, utilizing [2]rotaxane as the bridging unit. Under external force, the [2]rotaxane cross‐link undergoes intramolecular motion, releasing hidden chain and increasing the interlayer slip distance between graphene nanosheets. Compared with graphene films without [2]rotaxane cross‐linking, the presence of mechanical bond not only boosted the strength of graphene films (247.3 vs 74.8 MPa) but also markedly promoted the tensile strain (23.6 vs 10.2 %) and toughness (23.9 vs 4.0 MJ/m3). Notably, the achieved tensile strain sets a record high and the toughness surpasses most reported results, rendering the graphene films suitable for applications as flexible electrodes. Even when the films were stretched within a 20 % strain and repeatedly bent vertically, the light‐emitting diodes maintained an on‐state with little changes in brightness. Additionally, the film electrodes effectively actuated mechanical joints, enabling uninterrupted grasping movements. Therefore, the study holds promise for expanding the application of graphene films and simultaneously inspiring the development of other high‐performance two‐dimensional films.
Switchable Dual Circularly Polarized Luminescence in Through‐Space Conjugated Chiral Foldamers
Authors: Shen Pingchuan , Jiao Shaoshao , Zhuang Zeyan , Dong Xiaobin , Song Shaoxin , Li Jinshi , Tang Ben Zhong , Zhao Zujin
Published: May 2024

Organic materials with switchable dual circularly polarized luminescence (CPL) are highly desired because they can not only directly radiate tunable circularly polarized light themselves but also induce CPL for guests by providing a chiral environment in self‐assembled structures or serving as the hosts for energy transfer systems. However, most organic molecules only exhibit single CPL and it remains challenging to develop organic molecules with dual CPL. Herein, novel through‐space conjugated chiral foldamers are constructed by attaching two biphenyl arms to the 9,10‐positions of phenanthrene, and switchable dual CPL with opposite signs at different emission wavelengths are successfully realized in the foldamers containing high‐polarizability substitutes (cyano, methylthiol and methylsulfonyl). The combined experimental and computational results demonstrate that the intramolecular through‐space conjugation has significant contributions to stabilizing the folded conformations. Upon photoexcitation in high‐polar solvents, strong interactions between the biphenyl arms substituted with cyano, methylthio or methylsulfonyl and the polar environment induce conformation transformation for the foldamers, resulting in two transformable secondary structures of opposite chirality, accounting for the dual CPL with opposite signs. These findings highlight the important influence of the secondary structures on the chiroptical property of the foldamers and pave a new avenue towards efficient and tunable dual CPL materials.
Organocatalytic Enantioselective 1,12‐Addition of Alkynyl Biphenyl Quinone Methides Formed In Situ
Authors: Wang Xing , Shen Boming , Liu Meiwen , Wang Ziyang , Liu Chang , Li Pengfei , Yu Peiyuan , Li Wenjun
Published: May 2024

The chemistry of quinone methides formed in situ has been flourishing in recent years. In sharp contrast, the development and utilization of biphenyl quinone methides are rare. In this study, we achieved a remote stereocontrolled 1,12‐conjugate addition of biphenyl quinone methides formed in situ for the first time. In the presence of a suitable chiral phosphoric acid, alkynyl biphenyl quinone methides were generated from α‐[4‐(4‐hydroxyphenyl)phenyl]propargyl alcohols, followed by enantioselective 1,12‐conjugate addition with indole‐2‐carboxylates. The strategy enabled the alcohols to serve as efficient allenylation reagents, providing practical access to a broad range of axially chiral allenes bearing a (1,1′‐biphenyl)‐4‐ol unit, which were previously less accessible. Combined with control experiments, density functional theory calculations shed light on the reaction mechanism, indicating that enantioselectivity originates from the nucleophilic addition of alkynyl biphenyl quinone methides. Notably, not only the presence of biphenyl quinone methides as versatile intermediates was confirmed but also organocatalytic enantioselective 1,12‐addition was established.
Formation of a Porous Crystalline Mg1‐xAl2Oy Overlayer on Metal Catalysts via Controlled Solid‐State Reactions for High‐temperature Stable Catalysis
Authors: Cai Lihua , Han Shanlei , Xu Wenlong , Chen Si , Shi Xianxian , Lu Junling
Published: May 2024

Catalyst deactivation by sintering and coking is a long‐standing issue in metal‐catalyzed harsh high‐temperature hydrocarbon reactions. Ultrathin oxide coatings of metal nanocatalysts have recently appeared attractive to address this issue, while the porosity of the overlayer is difficult to control to preserve the accessibility of embedded metal nanoparticles, thus often leading to a large decrease in activity. Here, we report that a nanometer‐thick alumina coating of MgAl2O4‐supported metal catalysts followed by high‐temperature reduction can transform a nonporous amorphous alumina overlayer into a porous Mg1‐xAl2Oy crystalline spinel structure with a pore size of 2–3 nm and weakened acidity. The high porosity stems from the restrained Mg migration from the MgAl2O4 support to the alumina overlayer through solid‐state reactions at high temperatures. The resulting Ni/MgAl2O4 and Pt/MgAl2O4 catalysts with a porous crystalline Mg1‐xAl2Oy overlayer achieved remarkably high stability while preserving much higher activity than the corresponding alumina‐coated Ni and Pt catalysts on MgO and Al2O3 supports in the reactions of dry reforming of methane and propane dehydrogenation, respectively.
Experimental and numerical study on mechanical behavior of 3D printed adhesive joints with polycarbonate substrates
Authors: Öztürk Fatih Huzeyfe , Marques E. A. S. , Carbas R. J. C. , da Silva L. F. M.
Published: May 2024

Adhesive joints play a crucial role in enhancing the structural integrity and performance of 3D printed parts. The purpose of this study is to investigate the failure load and behavior of polycarbonate (PC) single lap joints (SLJs) produced by fused deposition modeling (FDM) using experimental and finite element analysis (FEA) methods. The FEA of joints presents a new approach by integrating PC substrates with Hill yield criterion, transversely isotropic material and adhesive layer with cohesive zone modeling (CZM). The study focused on the effect of printing angles (0°, 45°, and 90°) and overlap lengths (12.5 and 25 mm) on the performance of SLJs. The influence of 3D printing parameters on the mechanical behavior of PC joints was investigated by tensile testing of SLJs. The experimental failure load was 1586 N for a 12.5 mm joint at 90° and 4115 N for a 25.4 mm joint at 0°. Comparison of the experimental and FEA failure loads of the joints showed maximum and minimum differences of 11.98% and 1.34%, respectively. This result showed that the proposed model is applicable for determining the joint strength as a function of the printing angle and monitoring the joint damage behavior.
Fe3+‐activated magnetoplumbite persistent luminescence phosphor by modulating the oxygen vacancy
Authors: Du Zhan , Shang Huijun , Wang Bo , Pan Feng
Published: May 2024

Broadband near‐infrared (NIR) spectroscopy has gained significant attention due to its versatile application in various fields. In the realm of NIR phosphors, Fe3+ ion is an excellent activator known for its nontoxic and harmless nature. In this study, we prepared an Fe3+‐activated SrGa12O19 (SGO) NIR phosphor and analyzed its phase and luminescence properties. Upon excitation at 326 nm, the SGO:Fe3+ phosphor exhibited a broadband emission in the range 700–1000 nm, peaking at 816 nm. The optical band gap of SGO:Fe3+ was evaluated. To enhance the long‐lasting phosphorescence, an oxygen vacancy‐rich SGO:Fe3+ (VO‐SGO:Fe3+) sample was prepared for activation. Interestingly, the increase in the oxygen‐vacancy concentration indeed contributed to the activation of persistent luminescence of Fe3+ ions. The VO‐SGO:Fe3+ sample has a long duration and high charge storage capacity, allowing it to perform efficiently in various applications. This work provides the foundation for further design of Cr3+‐free PersL phosphors with efficient NIR PersL.
Reprogramming anchorage dependency to develop cell lines for recombinant protein expression
Authors: Lee Ju Young , Huh Hyunbin D. , Lee Dong Ki , Park So Yeon , Shin Ji Eun , Gee Heon Yung , Park Hyun Woo
Published: May 2024

As the biopharmaceutical industry continues to mature in its cost‐effectiveness and productivity, many companies have begun employing larger‐scale biomanufacturing and bioprocessing protocols. While many of these protocols require cells with anchorage‐independent growth, it remains challenging to induce the necessary suspension adaptations in many different cell types. In addition, although transfection efficiency is an important consideration for all cells, especially for therapeutic protein production, cells in suspension are generally more difficult to transfect than adherent cells. Thus, much of the biomanufacturing industry is focused on the development of new human cell lines with properties that can support more efficient biopharmaceutical production. With this in mind, we identified a set of “Adherent‐to‐Suspension Transition” (AST) factors, IKZF1, BTG2 and KLF1, the expression of which induces adherent cells to acquire anchorage‐independent growth. Working from the HEK293A cell line, we established 293‐AST cells and 293‐AST‐TetR cells for inducible and reversible reprogramming of anchorage dependency. Surprisingly, we found that the AST‐TetR system induces the necessary suspension adaptations with an accompanying increase in transfection efficiency and protein expression rate. Our AST‐TetR system therefore represents a novel technological platform for the development of cell lines used for generating therapeutic proteins.