485 research outputs found
Charge Transfer in Partition Theory
The recently proposed Partition Theory (PT) [J.Phys.Chem.A 111, 2229 (2007)]
is illustrated on a simple one-dimensional model of a heteronuclear diatomic
molecule. It is shown that a sharp definition for the charge of molecular
fragments emerges from PT, and that the ensuing population analysis can be used
to study how charge redistributes during dissociation and the implications of
that redistribution for the dipole moment. Interpreting small differences
between the isolated parts' ionization potentials as due to environmental
inhomogeneities, we gain insight into how electron localization takes place in
H2+ as the molecule dissociates. Furthermore, by studying the preservation of
the shapes of the parts as different parameters of the model are varied, we
address the issue of transferability of the parts. We find good transferability
within the chemically meaningful parameter regime, raising hopes that PT will
prove useful in chemical applications.Comment: 12 pages, 16 figure
Aberrant Cyclization Affords a C-6 Modified Cyclic Adenosine 5′-Diphosphoribose Analogue with Biological Activity in Jurkat T Cells
*S Supporting Information ABSTRACT: Two nicotinamide adenine dinucleotide (NAD +) analogues modified at the 6 position of the purine ring were synthesized, and their substrate properties toward Aplysia californica ADP-ribosyl cyclase were investigated. 6-N-Methyl NAD + (6-N-methyl nicotinamide adenosine 5′-dinucleotide 10) hydrolyzes to give the linear 6-N-methyl ADPR (adenosine 5′-diphosphoribose, 11), whereas 6-thio NHD + (nicotinamide 6-mercaptopurine 5′-dinucleotide, 17) generates a cyclic dinucleotide. Surprisingly, NMR correlation spectra confirm this compound to be the N1 cyclic product 6-thio N1-cIDPR (6-thio cyclic inosine 5′-diphosphoribose, 3), although the corresponding 6-oxo analogue is well-known to cyclize at N7. In Jurkat T cells, unlike the parent cyclic inosine 5′-diphosphoribose N1-cIDPR 2, 6-thio N1-cIDPR antagonizes both cADPR- and N1cIDPR-induced Ca 2+ release but possesses weak agonist activity at higher concentration. 3 is thus identified as the first C-6 modified cADPR (cyclic adenosine 5′-diphosphoribose) analogue antagonist; it represents the first example of a fluorescent N1cyclized cADPR analogue and is a new pharmacological tool for intervention in the cADPR pathway of cellular signaling
Incomplete but Infectious Vaccinia Virions Are Produced in the Absence of Oncolysis in Feline SCCF1 Cells
Vaccinia virus is a large, enveloped virus of the poxvirus family. It has broad tropism and typically virus replication culminates in accumulation and lytic release of intracellular mature virus (IMV), the most abundant form of infectious virus, as well as release by budding of extracellular enveloped virus (EEV). Vaccinia viruses have been modified to replicate selectively in cancer cells and clinically tested as oncolytic agents. During preclinical screening of relevant cancer targets for a recombinant Western Reserve strain deleted for both copies of the thymidine kinase and vaccinia growth factor genes, we noticed that confluent monolayers of SCCF1 cat squamous carcinoma cells were not destroyed even after prolonged infection. Interestingly, although SCCF1 cells were not killed, they continuously secreted virus into the cell culture supernatant. To investigate this finding further, we performed detailed studies by electron microscopy. Both intracellular and secreted virions showed morphological abnormalities on ultrastructural inspection, suggesting compromised maturation and morphogenesis of vaccinia virus in SCCF1 cells. Our data suggest that SCCF1 cells produce a morphologically abnormal virus which is nevertheless infective, providing new information on the virus-host cell interactions and intracellular biology of vaccinia virus.Peer reviewe
iPrevent
Curso de Especial InterésLa siguiente propuesta, contiene la información necesaria para poder asesorar y brindar
una mejor atención a los procesos que son inherentes a la sexualidad del ser humano. El diseño de la creación de una aplicación llamada iPrevent, usada en aparatos tecnológicos como los móviles con sistema Android y Apple. Esta aplicación está encaminada a presentar y a exponer los distintos métodos anticonceptivos que se encuentran en el mercado, así mismo brindar un marco de conocimiento de cada uno, para facilitar la toma de decisiones de los adolescentes; de esta manera teniendo una correlación con la salud pública y mitigar los embarazos no deseados y posibles interrupciones voluntarias del embarazo (IVE) y uso de Métodos Anticonceptivos de emergencia en esta población.101 p.1. Resumen
2. Justificación
3. Marco teórico
4. Objetivos
5. Metodología
6. Estudio de mercadeo
7. Resultados
8. Discusión
9. Conclusiones y recomendaciones
10. Referencias
11. ApéndicesPregradoPsicólog
LEM-3 is a midbody-tethered DNA nuclease that resolves chromatin bridges during late mitosis
Chromosome segregation and genome maintenance require the removal of DNA bridges that link chromosomes just before cells divide. Here the authors show that the LEM-3/Ankle1 nuclease processes DNA bridges before cells divide and define a previously undescribed genome integrity mechanism
Activity-Dependent Exocytosis of Lysosomes Regulates the Structural Plasticity of Dendritic Spines
Lysosomes have traditionally been viewed as degradative organelles, though a growing body of evidence suggests that they can function as Ca2+ stores. Here, we examined the function of these stores in hippocampal pyramidal neurons. We found that back-propagating action potentials (bpAPs) could elicit Ca2+ release from lysosomes in the dendrites. This Ca2+ release triggered the fusion of lysosomes with the plasma membrane, resulting in the release of Cathepsin B. Cathepsin B increased the activity of matrix metalloproteinase 9 (MMP-9), an enzyme involved in extracellular matrix (ECM) remodelling and synaptic plasticity. Inhibition of either lysosomal Ca2+ signalling or Cathepsin B release prevented the maintenance of dendritic spine growth induced by Hebbian activity. This impairment could be rescued by exogenous application of active MMP-9. Our findings suggest that activity-dependent exocytosis of Cathepsin B from lysosomes regulates the long-term structural plasticity of dendritic spines by triggering MMP-9 activation and ECM remodelling
Evaluation of a Fotonovela to Increase Depression Knowledge and Reduce Stigma Among Hispanic Adults
Fotonovelas—small booklets that portray a dramatic story using photographs and captions— represent a powerful health education tool for low-literacy and ethnic minority audiences. This study evaluated the effectiveness of a depression fotonovela in increasing depression knowledge, decreasing stigma, increasing self-efficacy to recognize depression, and increasing intentions to seek treatment, relative to a text pamphlet. Hispanic adults attending a community adult school (N = 157, 47.5 % female, mean age = 35.8 years, 84 % immigrants, 63 % with less than high school education) were randomly assigned to read the fotonovela or a low-literacy text pamphlet about depression. They completed surveys before reading the material, immediately after reading the material, and 1 month later. The fotonovela and text pamphlet both produced significant improvements in depression knowledge and self-efficacy to identify depression, but the fotonovela produced significantly larger reductions in antidepressant stigma and mental health care stigma. The fotonovela also was more likely to be passed on to family or friends after the study, potentially increasing its reach throughout the community. Results indicate that fotonovelas can be useful for improving health literacy among underserved populations, which could reduce health disparities
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