Coordination polymer flexibility leads to polymorphism and enables a crystalline solid-vapour reaction: a multi-technique mechanistic study.

Despite an absence of conventional porosity, the 1D coordination polymer [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 ] (1; TMP=tetramethylpyrazine) can absorb small alcohols from the vapour phase, which insert into AgO bonds to yield coordination polymers [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 (ROH)2 ] (1-ROH; R=Me, Et, iPr). The reactions are reversible single-crystal-to-single-crystal transformations. Vapour-solid equilibria have been examined by gas-phase IR spectroscopy (K=5.

Quantitative comparison of structure and dynamics of elastin following three isolation schemes by 13C solid state NMR and MALDI mass spectrometry.

Methods for isolating elastin from fat, collagen, and muscle, commonly used in the design of artificial elastin based biomaterials, rely on exposing tissue to harsh pH levels and temperatures that usually denature many proteins. At present, a quantitative measurement of the modifications to elastin following isolation from other extracellular matrix constituents has not been reported. Using magic angle spinning (13)C NMR spectroscopy and relaxation methodologies, we have measured the modification in structure and dynamics following three known purification protocols.

Arabidopsis AtPARK13, which confers thermotolerance, targets misfolded proteins.

Mutations in HTRA2/Omi/PARK13 have been implicated in Parkinson disease (PD). PARK13 is a neuroprotective serine protease; however, little is known about how PARK13 confers stress protection and which protein targets are directly affected by PARK13. We have reported that Arabidopsis thaliana represents a complementary PD model, and here we demonstrate that AtPARK13, similar to human PARK13 (hPARK13), is a mitochondrial protease.

Use of the Internet and mobile-based "apps" for sex-seeking among men who have sex with men in New York City.

The Internet continues to be a popular venue for men who have sex with men (MSM) to seek sexual partners. Increased sexual risk behavior has been linked to MSM who use the Internet to seek partners. However, there has been little research on how new mobile-based social networking applications ("apps") may affect sex-seeking and sexual risk behaviors of MSM.

Tethered domains and flexible regions in tRNase Z(L), the long form of tRNase Z.

tRNase Z, a member of the metallo-β-lactamase family, endonucleolytically removes the pre-tRNA 3' trailer in a step central to tRNA maturation. The short form (tRNase Z(S)) is the only one found in bacteria and archaebacteria and is also present in some eukaryotes. The homologous long form (tRNase Z(L)), exclusively found in eukaryotes, consists of related amino- and carboxy-domains, suggesting that tRNase Z(L) arose from a tandem duplication of tRNase Z(S) followed by interdependent divergence of the domains.

Examining HIV-positive parents' disclosure to their children: a biopsychosocial approach.

In the post HAART era, the biopsychosocial issues now facing HIV-positive parents concerning disclosure of their status to their children need to be understood in the context of chronic disease. This article describes the experiences of 101 adult HIV-positive urban in-treatment mothers and fathers of school-age children on disclosure, psychological distress, social support, and symptom severity. Key variables associated with parents' HIV disclosure were the age of parent and of children in the household, parents' HIV-related symptoms, and parent ethnicity.

Pathogenesis-related mutations in the T-loops of human mitochondrial tRNAs affect 3' end processing and tRNA structure.

Numerous mutations in the mitochondrial genome are associated with maternally transmitted diseases and syndromes that affect muscle and other high energy-demand tissues. The mitochondrial genome encodes 13 polypeptides, 2 rRNAs and 22 interspersed tRNAs via long bidirectional polycistronic primary transcripts, requiring precise excision of the tRNAs. Despite making up only ~10% of the mitochondrial genome, tRNA genes harbor most of the pathogenesis-related mutations.

Protein-DNA interactions define the mechanistic aspects of circle formation and insertion reactions in IS2 transposition.

Background: Transposition in IS3, IS30, IS21 and IS256 insertion sequence (IS) families utilizes an unconventional two-step pathway. A figure-of-eight intermediate in Step I, from asymmetric single-strand cleavage and joining reactions, is converted into a double-stranded minicircle whose junction (the abutted left and right ends) is the substrate for symmetrical transesterification attacks on target DNA in Step II, suggesting intrinsically different synaptic complexes (SC) for each step. Transposases of these ISs bind poorly to cognate DNA and comparative biophysical analyses of SC I and SC II have proven elusive.

Soluble expression, purification and characterization of the full length IS2 Transposase.

Background: The two-step transposition pathway of insertion sequences of the IS3 family, and several other families, involves first the formation of a branched figure-of-eight (F-8) structure by an asymmetric single strand cleavage at one optional donor end and joining to the flanking host DNA near the target end. Its conversion to a double stranded minicircle precedes the second insertional step, where both ends function as donors. In IS2, the left end which lacks donor function in Step I acquires it in Step II.

Disrupted caregiving and maternal HIV disease: a proposed model for evaluating HIV-affected children's psychosocial adjustment.

A current concern among social science researchers is the impact of human immunodeficiency virus (HIV) disease on the family, especially on the parenting abilities of mothers with HIV. Beginning research suggests that the children of HIV-positive parents are vulnerable, pointing to the impact of HIV disease on children's social and emotional adjustment. The objective of this article is to propose a model of the HIV disease-related disruption of care on children's psychosocial adjustment.

Online sex-seeking behaviors of men who have sex with men in New York City.

The ongoing HIV epidemic among men who have sex with men (MSM) in New York City and the increased use of Internet sexual social networking websites by MSM fosters a need to understand the characteristics and sex-related behaviors of this group. The authors conducted an online survey of 195 MSM who use sexual social networking websites in New York City. Demographic characteristics, sexual sensation seeking, and HIV optimism-skepticism were compared among participants reporting sex with and without condom use (safe sex and high-risk sex, respectively) with partners met online.

Effect of changes in the flexible arm on tRNase Z processing kinetics.

tRNAs are transcribed as precursors and processed in a series of reactions culminating in aminoacylation and translation. Central to tRNA maturation, the 3' end trailer can be endonucleolytically removed by tRNase Z. A flexible arm (FA) extruded from the body of tRNase Z consists of a structured alphaalphabetabeta hand that binds the elbow of pre-tRNA.

Biocytin wide-field bipolar cells in rabbit retina selectively contact blue cones.

The biocytin wide-field bipolar cell in rabbit retina has a broad axonal arbor in layer 5 of the inner plexiform layer and a wide dendritic arbor that does not contact all cones in its dendritic field. The purpose of our study was to identify the types of cones that this cell contacts. We identified the bipolar cells by selective uptake of biocytin, labeled the cones with peanut agglutinin, and then used antibodies against blue cone opsin and red-green cone opsin to identify the individual cone types.

High resolution q-space imaging studies of water in elastin.

We report on the direct measurement of the molecular diffusion coefficients of water confined to purified bovine nuchal ligament elastin by high resolution q-space NMR imaging. The experimental data indicate that water trapped within an elastin fiber has two distinguishable molecular diffusion coefficients. The component with the slowest mobility has a diffusion coefficient on the order of 10(-6) cm(2)/s that varies inversely with the diffusion time and is seen to reduce near 37 degrees C.

Prediction of cyclin-dependent kinase phosphorylation substrates.

Protein phosphorylation, mediated by a family of enzymes called cyclin-dependent kinases (Cdks), plays a central role in the cell-division cycle of eukaryotes. Phosphorylation by Cdks directs the cell cycle by modifying the function of regulators of key processes such as DNA replication and mitotic progression. Here, we present a novel computational procedure to predict substrates of the cyclin-dependent kinase Cdc28 (Cdk1) in the Saccharomyces cerevisiae.

tRNase Z catalysis and conserved residues on the carboxy side of the His cluster.

tRNAs are transcribed as precursors and processed in a series of required reactions leading to aminoacylation and translation. The 3'-end trailer can be removed by the pre-tRNA processing endonuclease tRNase Z, an ancient, conserved member of the beta-lactamase superfamily of metal-dependent hydrolases. The signature sequence of this family, the His domain (HxHxDH, Motif II), and histidines in Motifs III and V and aspartate in Motif IV contribute seven side chains for the coordination of two divalent metal ions.

Adolescents' psychological response to the experience of community interpersonal violence: a cross-national and a cross-cultural comparison.

A comparative cross-national study investigating the level of experience with community interpersonal violence, level of psychological distress, and the relationship between exposure and distress among adolescents is presented. Participants were 617 first-year college students comprising African Americans and Jamaican Americans living in New York City, and Jamaicans living in Kingston, Jamaica. The three groups are similar in terms of age, gender, educational level, and race; they differ in location of residence, culture, and immigration status.

Residues in two homology blocks on the amino side of the tRNase Z His domain contribute unexpectedly to pre-tRNA 3' end processing.

tRNase Z, which can endonucleolytically remove pre-tRNA 3'-end trailers, possesses the signature His domain (HxHxDH; Motif II) of the beta-lactamase family of metal-dependent hydrolases. Motif II combines with Motifs III-V on its carboxy side to coordinate two divalent metal ions, constituting the catalytic core. The PxKxRN loop and Motif I on the amino side of Motif II have been suggested to modulate tRNase Z activity, including the anti-determinant effect of CCA in mature tRNA.

Naturally occurring mutations in human mitochondrial pre-tRNASer(UCN) can affect the transfer ribonuclease Z cleavage site, processing kinetics, and substrate secondary structure.

tRNAs are transcribed as precursors with a 5' end leader and a 3' end trailer. The 5' end leader is processed by RNase P, and in most organisms in all three kingdoms, transfer ribonuclease (tRNase) Z can endonucleolytically remove the 3' end trailer. Long ((L)) and short ((S)) forms of the tRNase Z gene are present in the human genome.

Residues in the conserved His domain of fruit fly tRNase Z that function in catalysis are not involved in substrate recognition or binding.

Transfer RNAs are transcribed as precursors with extensions at both the 5' and 3' ends. RNase P removes endonucleolytically the 5' end leader. tRNase Z can remove endonucleolytically the 3' end trailer as a necessary step in tRNA maturation.

The effect of personal characteristics on reporting child maltreatment.

Objective: This study examined the relationship between personal characteristics of 276 potential entry-level social service workers and their decision to report child maltreatment to Child Protective Services (CPS). The personal characteristics of interest were: age, gender, parenthood, mother's education, father's education, college major, ethnicity, and immigrant status. The study hypotheses were that personal characteristics would have: (1) an individual effect on reporting, (2) a combined effect on reporting, and (3) an effect on reporting beyond any effect mediated by approval of corporal punishment and perceptions of maltreatment.

Deconstructing stigma: perceptions of HIV-seropositive mothers and their disclosure to children.

This study addressed the perceptions of stigma and disclosure behavior of HIV-seropositive mothers. Eighty-eight HIV-seropositive women in New York City completed two independent measures of stigma, the Perceived Stigma Scale and the Devaluation-Discrimination Measure. Disclosers (67%) and nondisclosers (33%) were similar in most sociodemographic characteristics-marital status, race, religion and employment, with the exception of age and education.

Left ventricular function during strength testing and resistance exercise in patients with left ventricular dysfunction.

Purpose: Deterioration in left ventricular function is a more sensitive marker of myocardial ischemia during exercise than ST segment depression. The current study was designed to evaluate left ventricular function during one-repetition-maximum (1-RM) strength testing and resistance exercise in cardiac patients with moderate left ventricular dysfunction.

Methods: Using echocardiographic methods, left ventricular function was evaluated in 15 patients with left ventricular dysfunction (age, 65 +/- 6.

The association of ecological variables and psychological distress with exposure to community violence among adolescents.

Ecological theory suggests that exposure to community violence should be related to individual, family, and community characteristics; traumatic stress theory suggests that exposure to community violence should be related to level of psychological distress. A correlational study of 468 older adolescents in New York City tested these hypotheses. Exposure was found to be moderately related to level of psychological distress, but was not related to family or neighborhood characteristics.

The left end of IS2: a compromise between transpositional activity and an essential promoter function that regulates the transposition pathway.

Cut-and-paste (simple insertion) and replicative transposition pathways are the two classical paradigms by which transposable elements are mobilized. A novel variation of cut and paste, a two-step transposition cycle, has recently been proposed for insertion sequences of the IS3 family. In IS2 this variation involves the formation of a circular, putative transposition intermediate (the minicircle) in the first step.