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1.
Angew Chem Int Ed Engl ; : e202411156, 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39136344

RESUMEN

A reagent-controlled diastereodivergent copper-catalyzed borylative difunctionalization is reported. The formation of Lewis adducts that guide selectivity is commonly invoked in organic reaction mechanisms. Using density functional theory calculations, we identified BpinBdan as a sterically similar and less Lewis acidic alternative to B-2pin2. Using a newly developed borylative aldol domino reaction as the proof-of-concept, we demonstrate a change in stereochemical outcome by a simple change of borylating reagent - B2pin2 affords the diastereomer associated with coordination control while BpinBdan overturns this mode of binding. We show that this strategy can be generalized to other scaffolds and, more importantly, that BpinBdan does not alter the diastereomeric outcome of the reaction when coordination is not involved. BpinBdan can be viewed as a mechanistic probe for coordination in future copper-catalyzed borylation reactions.

2.
Nat Commun ; 15(1): 5529, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38956039

RESUMEN

Left unchecked, plant-parasitic nematodes have the potential to devastate crops globally. Highly effective but non-selective nematicides are justifiably being phased-out, leaving farmers with limited options for managing nematode infestation. Here, we report our discovery of a 1,3,4-oxadiazole thioether scaffold called Cyprocide that selectively kills nematodes including diverse species of plant-parasitic nematodes. Cyprocide is bioactivated into a lethal reactive electrophilic metabolite by specific nematode cytochrome P450 enzymes. Cyprocide fails to kill organisms beyond nematodes, suggesting that the targeted lethality of this pro-nematicide derives from P450 substrate selectivity. Our findings demonstrate that Cyprocide is a selective nematicidal scaffold with broad-spectrum activity that holds the potential to help safeguard our global food supply.


Asunto(s)
Antinematodos , Sistema Enzimático del Citocromo P-450 , Nematodos , Animales , Sistema Enzimático del Citocromo P-450/metabolismo , Nematodos/efectos de los fármacos , Antinematodos/farmacología , Sulfuros/farmacología , Sulfuros/química
3.
Hong Kong Physiother J ; 44(2): 91-102, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38510154

RESUMEN

Background: Self-efficacy expresses a learner's perception of how well they can do in the online academic setting. Although students' academic successes can be measured by online learning self-efficacy, there is a scarcity of evidence targeted toward allied health students. Objective: The primary aim of this study is to determine the level of online self-efficacy among students from skill-based allied health programs. The secondary aim is to correlate online self-efficacy with age, sex, year level, and program of the students. Methods: This cross-sectional analytic study utilized the Online Learning Self-Efficacy Scale (OLSE) to determine students' level of self-efficacy via a survey conducted with students who underwent the Enriched Virtual Mode of learning. Descriptive statistics was used to characterize the study participants, describe the level of self-efficacy, and compare the subscales of OLSE. Inferential statistics using Spearman's rho was performed to determine the correlation. Results: A total of 117 respondents with a mean age ± SD of 20.59 ± 0.11 years old, predominantly female (71%) were included in the study. The students from allied health programs had an online self-efficacy overall mean score of 3.83 (SD=0.05; range 2.64-5.00) with the use of technology subscales weighted the highest mean score (4.24). Females have a higher average OLSE score (M=3.92, SD=0.05) compared to males. Significant correlation was found between OLSE scores to sex (r=0.260, p=0.005) and year level (r=-0.199, p=0.031) while nonsignificant correlation was found between OLSE scores to the program (r=-0.048, p=0.604) and age (r=-0.123, p=0.185). Conclusion: Students of allied health programs generally have a very good level of online self-efficacy. This study assists educators in developing proactive strategies and approaches to promote students' self-confidence across all domains and encourage them to adopt a dynamic remote learning-based approach. Educational institutions should use this opportunity to assess how well they have implemented remote learning to ensure educational continuity, especially in times of crisis.

4.
Nat Commun ; 14(1): 1816, 2023 03 31.
Artículo en Inglés | MEDLINE | ID: mdl-37002199

RESUMEN

Nematode parasites of humans and livestock pose a significant burden to human health, economic development, and food security. Anthelmintic drug resistance is widespread among parasites of livestock and many nematode parasites of humans lack effective treatments. Here, we present a nitrophenyl-piperazine scaffold that induces motor defects rapidly in the model nematode Caenorhabditis elegans. We call this scaffold Nemacol and show that it inhibits the vesicular acetylcholine transporter (VAChT), a target recognized by commercial animal and crop health groups as a viable anthelmintic target. We demonstrate that it is possible to create Nemacol analogs that maintain potent in vivo activity whilst lowering their affinity to the mammalian VAChT 10-fold. We also show that Nemacol enhances the ability of the anthelmintic Ivermectin to paralyze C. elegans and the ruminant nematode parasite Haemonchus contortus. Hence, Nemacol represents a promising new anthelmintic scaffold that acts through a validated anthelmintic target.


Asunto(s)
Antihelmínticos , Nematodos , Animales , Humanos , Caenorhabditis elegans , Proteínas de Transporte Vesicular de Acetilcolina , Antihelmínticos/farmacología , Ivermectina/farmacología , Resistencia a Medicamentos , Mamíferos
5.
Br J Radiol ; 95(1136): 20211165, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35671135

RESUMEN

OBJECTIVE: We aimed to investigate if the use of read-out segmented echoplanar imaging with additional two-dimensional navigator correction (Readout Segmentation of Long Variable Echo, RESOLVE) for acquiring prostate diffusion-weighted imaging (DWI) improves image quality, compared to single-shot echoplanar imaging (ss-EPI). METHODS: This single-center prospective study cohort included 162 males with suspected prostate cancer, who underwent 3 Tesla multiparametric MRI (3T-mpMRI). Two abdominal radiologists, blinded to the clinical information, separately reviewed each 3T-mpMRI study to rank geometrical distortion, degree of rectal distention, lesion conspicuity, and anatomic details delineation first on ss-EPI-DWI and later on RESOLVE-DWI using 5-point scales (1 = excellent, 5 = poor). The average of the ranking scores given by two readers was generated and used as the final score. RESULTS: There was good-to-excellent interreader agreement for scoring image quality parameters on both ss-EPI and RESOLVE. Geometrical distortion scores > 3 was seen in 12.3% (20/162) of ss-EPI images, with all having geometrical distortion score <3 on RESOLVE (p < .001). The mean image distortion score was significantly less on RESOLVE than ss-EPI (1.16 vs 1.61, p < .01 regardless of rectal gas, p< .05 when stratified by the degree of rectal distention ). RESOLVE was superior to ss-EPI for lesion conspicuity (mean 1.35 vs 1.53, p< .002) and anatomic delineation (2.60 vs 2.68, p< .001) of prostate on DWI. CONCLUSION: Compared to conventional ss-EPI, the use of RESOLVE for acquisition of prostate DWI resulted in significantly enhanced image quality and reduced geometrical distortion. ADVANCES IN KNOWLEDGE: RESOLVE could be an alternative or replacement of ss-EPI for acquiring prostate DWI with significantly less geometrical distortion and significantly improved lesion conspicuity and anatomic delineation.


Asunto(s)
Imagen Eco-Planar , Próstata , Imagen de Difusión por Resonancia Magnética/métodos , Imagen Eco-Planar/métodos , Humanos , Masculino , Pelvis , Estudios Prospectivos , Próstata/diagnóstico por imagen
6.
Angew Chem Int Ed Engl ; 61(8): e202116171, 2022 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-34939302

RESUMEN

The dearomatization of 2-naphthols represents a simple method for the construction of complex 3D structures from simple planar starting materials. We describe a cyclopropanation of 2-naphthols that proceeds via cyclopropene ring-opening using rhodium and acid catalysis under mild conditions. The vinyl cyclopropane molecules were formed with high chemoselectivity and scalability, which could be further functionalized at different sites. Both computational and experimental evidence were used to elucidate the reaction mechanism.

7.
Int J Neural Syst ; 18(6): 491-526, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19145665

RESUMEN

We present a machine learning approach to discover the agent dynamics that drives the evolution of the social groups in a community. We set up the problem by introducing an agent-based hidden Markov model for the agent dynamics: an agent's actions are determined by micro-laws. Nonetheless, We learn the agent dynamics from the observed communications without knowing state transitions. Our approach is to identify the appropriate micro-laws corresponding to an identification of the appropriate parameters in the model. The model identification problem is then formulated as a mixed optimization problem. To solve the problem, we develop a multistage learning process for determining the group structure, the group evolution, and the micro-laws of a community based on the observed set of communications among actors, without knowing the semantic contents. Finally, to test the quality of our approximations and the feasibility of the approach, we present the results of extensive experiments on synthetic data as well as the results on real communities, such as Enron email and Movie newsgroups. Insight into agent dynamics helps us understand the driving forces behind social evolution.


Asunto(s)
Inteligencia Artificial , Relaciones Interpersonales , Aprendizaje , Cadenas de Markov , Modelos Estadísticos , Algoritmos , Comunicación , Simulación por Computador , Humanos , Dinámicas no Lineales , Factores de Tiempo
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