9,528 research outputs found
Relationship between chromatin bridges in anaphase and chromosomal aberrations induced by TMP+UVA (365 nm) in CHO cells
In a recent paper, the hypothesis of 'conservative pairing' between complementary DNA strands belonging to both sister chromatids has been proposed as a phenomenon that could account for, at least in part, sister chromatid pairing in late G(2)/mitosis. The hypothesis was verified through a cytogenetic approach, studying the so-called 'sister chromatid chromatin bridges' (SCCBs), induced in the previous G(2)/mitosis by a crosslinking (TMP + UVA 365 nm) treatment in CHO cells (Rizzoni, M., E. Cundari, P. Perticone and B. Gustavino (1993) Chromatin bridges between sister chromatids induced in late G(2) mitosis in CHO cells by trimethylpsoralen + UVA, Experimental Cell Res., 209, 149-155; [1]). The purpose of the present paper is the study of the relationship between chromatin bridges without fragments in ana-telophase, which were demonstrated to be SCCBs, and chromosomal aberrations, in order to investigate their mechanism of induction. The evolution along the time of the two classes of mitotic anomalies was studied and a comparison was carried out to verify whether the bridges rise as a direct and immediate effect of the treatment or represent the misrepair-mediated effect of it. The present data show that single bridges without fragments come from a direct effect of photoinduced crosslinks in late G(2)/mitosis. Moreover TMP + 365 nm UVA treatment shows an S-dependent clastogenic effect. The proposed hypothesis of 'conservative pairing' between DNA strands of sister chromatids is further supported
Durability of biodegradable polymers for the conservation of cultural heritage
The use of polymers for conservation of cultural heritage is related to the possibility to slow down or stop natural deterioration which, in many cases, corresponds to stopping the entrance of liquid water and to favor spontaneous water vapor removal. Unfortunately, hydrophobicity is generally favored by surface roughness and thus competitive with transparency. It is therefore important to find an optimal balance hydrophobicity, transparency and durability (especially to photooxidation). However, polymers typically used for applications in this field come from non-renewable resources and are not biodegradable. In this work, the mechanical, structural, and optical properties of PLA, PBAT, and a PBAT/PLA blends, as well as surface properties and water vapor permeability, were investigated before and after exposure to UV irradiation, in order to evaluate their durability and suitability for conservation of cultural heritage
New plant trait records of the Hungarian flora
Canopy height, leaf area (LA), specific leaf area (SLA) and leaf dry matter content (LDMC) data of 210 species of the Hungarian flora resulting from our field sampling are presented in this data paper
IR ion spectroscopy in a combined approach with MS/MS and IM-MS to discriminate epimeric anthocyanin glycosides (cyanidin 3-O-glucoside and -galactoside)
Anthocyanins are widespread in plants and flowers, being responsible for their different colouring. Two representative members of this family have been selected, cyanidin 3-O-β-glucopyranoside and 3-O-β-galactopyranoside, and probed by mass spectrometry based methods, testing their performance in discriminating between the two epimers. The native anthocyanins, delivered into the gas phase by electrospray ionization, display a comparable drift time in ion mobility mass spectrometry (IM-MS) and a common fragment, corresponding to loss of the sugar moiety, in their collision induced dissociation (CID) pattern. However, the IR multiple photon dissociation (IRMPD) spectra in the fingerprint range show a feature particularly evident in the case of the glucoside. This signature is used to identify the presence of cyanidin 3-O-β-glucopyranoside in a natural extract of pomegranate. In an effort to increase any differentiation between the two epimers, aluminum complexes were prepared and sampled for elemental composition by FT-ICR-MS. CID experiments now display an extensive fragmentation pattern, showing few product ions peculiar to each species. More noteworthy is the IRMPD behavior in the OH stretching range showing significant differences in the spectra of the two epimers. DFT calculations allow to interpret the observed distinct bands due to a varied network of hydrogen bonding and relative conformer stability
Practice transformations to optimize the delivery of HIV primary care in community healthcare settings in the United States: A program implementation study.
BackgroundThe United States HIV care workforce is shrinking, which could complicate service delivery to people living with HIV (PLWH). In this study, we examined the impact of practice transformations, defined as efficiencies in structures and delivery of care, on demonstration project sites within the Workforce Capacity Building Initiative, a Health Resources and Services Administration (HRSA) Ryan White HIV/AIDS Program Special Projects of National Significance (SPNS).Methods and findingsData were collected at 14 demonstration project sites in 7 states and the District of Columbia. Organizational assessments were completed at sites once before and 4 times after implementation. They captured 3 transformation approaches: maximizing the HIV care workforce (efforts to increase the number of existing healthcare workforce members involved in the care of PLWH), share-the-care (team-based care giving more responsibility to midlevel providers and staff), and enhancing client engagement in primary HIV care to reduce emergency and inpatient care (e.g., care coordination). We also obtained Ryan White HIV/AIDS Program Services Reports (RSRs) from sites for calendar years (CYs) 2014-2016, corresponding to before, during, and after transformation. The RSR include data on client retention in HIV care, prescription of antiretroviral therapy (ART), and viral suppression. We used generalized estimating equation (GEE) models to analyze changes among sites implementing each practice transformation approach. The demonstration projects had a mean of 18.5 prescribing providers (SD = 23.5). They reported data on more than 13,500 clients per year (mean = 969/site, SD = 1,351). Demographic characteristics remained similar over time. In 2014, a majority of clients were male (71% versus 28% female and 0.2% transgender), with a mean age of 47 (interquartile range [IQR] 37-54). Racial/ethnic characteristics (48% African American, 31% Hispanic/Latino, 14% white) and HIV risk varied (31% men who have sex with men; 31% heterosexual men and women; 7% injection drug use). A substantial minority was on Medicaid (41%). Across sites, there was significant uptake in practices consistent with maximizing the HIV care workforce (18% increase, p < 0.001), share-the-care (25% increase, p < 0.001), and facilitating patient engagement in HIV primary care (13% increase, p < 0.001). There were also significant improvements over time in retention in HIV care (adjusted odds ratio [aOR] = 1.03; 95% confidence interval [CI] 1.02-1.04; p < 0.001), ART prescription levels (aOR = 1.01; 95% CI 1.00-1.01; p < 0.001), and viral suppression (aOR = 1.03; 95% CI 1.02-1.04; p < 0.001). All outcomes improved at sites that implemented transformations to maximize the HIV care workforce or improve client engagement. At sites that implemented share-the-care practices, only retention in care and viral suppression outcomes improved. Study limitations included use of demonstration project sites funded by the Ryan White HIV/AIDS Program (RWHAP), which tend to have better HIV outcomes than other US clinics; varying practice transformation designs; lack of a true control condition; and a potential Hawthorne effect because site teams were aware of the evaluation.ConclusionsIn this study, we found that practice transformations are a potential strategy for addressing anticipated workforce challenges among those providing care to PLWH. They hold the promise of optimizing the use of personnel and ensuring the delivery of care to all in need while potentially enhancing HIV care continuum outcomes
Caloric stimulation of ampullar receptors: a new method to produce mechanically-evoked responses in frog semicircular canals
A microthermistor positioned close to the exposed posterior semicircular canal in isolated labyrinth preparations of the frog was used to stimulate the sensory organ. Our results indicated that, depending on the position of the heater, the induced endolymphatic convection currents may result in either excitatory or inhibitory cupular deflections and thus in a modulation of ampullar receptor resting activity. Other possible thermal-dependent mechanisms, such as a direct action of the stimulus on vestibular sensors or endolymphatic volume changes, had, in the present experimental conditions, a minor role. Caloric stimulation could therefore represent a novel method to stimulate the semicircular canals 'in situ'
Chirality effects on the IRMPD spectra of basket resorcinarene/nucleoside complexes
The IRMPD spectra of the
ESI-formed proton-bound complexes
of the R,R,R,R- and S,S,S,S-enantiomers
of a bis(diamido)-bridged basket
resorcin[4]arene (R and S) with cytosine
(1), cytidine (2), and cytarabine
(3) were measured in the region 2800–
3600 cm1. Comparison of the IRMPD
spectra with the corresponding
ONIOM (B3LYP/6-31(d):UFF)-calculated
absorption frequencies allowed
the assessment of the vibrational
modes that are responsible for the observed
spectroscopic features. All of
the complexes investigated, apart from
[R·H·3]+, showed similar IRMPD spectra,
which points to similar structural
and conformational landscapes. Their
IRMPD spectra agree with the formation
of several isomeric structures in
the ESI source, wherein the N(3)-protonated
guest establishes noncovalent
interactions with the host amidocarbonyl
groups that are either oriented
inside the host cavity or outside it between
one of the bridged side-chains
and the upper aromatic nucleus. The
IRMPD spectrum of the [R·H·3]+ complex
was clearly different from the
others. This difference is attributed to the effect of intramolecular hydrogen bonding interactions between the
C(2’)-OH group and the aglycone oxygen atom of the nucleosidic guest upon repulsive interactions between
the same oxygen atom and the aromatic rings of the host
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