Quantum symmetry and photoreactivity of azabenzenes

The fundamental processes associated with a photochemical reaction are described with reference to experimental properties of azabenzenes. Consideration of both excitation and relaxation processes led to presentation of the symmetry propagator, a unifying principle which maps system fluctuations (perturbations acting on an initial state) with dissipations (transitions to different states), thus directing the energy flow along competing reactive and nonreactive pathways. A coherent picture of relaxation processes including chemical reactions was constructed with the aid of spectroscopic data. Pyrazine (1,4 diazine) possesses vibronically active modes which provide an efficient mechanism for internal conversion to the first excited singlet state, where other promoting modes of the correct symmetry induce both intersystem crossing to the triplet manifold, isomerization through diaza-benzvalene, and chemical reactions through cycloreversion of dewar pyrazine to yield HCN plus an azete. At higher energies simple H atom loss and internal conversion become more predominant, leading to ring opening followed by elimination of methylene nitrile and ground state reaction products. Efficiency of chemical transformations as dissipation mechanisms versus competing fluorescence, phosphorescence and radiationless relaxation was mapped from near ultraviolet to far ultraviolet by photodissociation quantum yields into reaction channels characterized by molecular beam photofragment translational spectroscopy. A reaction path model for azabenzene photochemistry was presented and tested against experiment. Presence of undiscovered channels in other azabenzene systems was predicted and verified. The dominant process, HCN elimination, was resolved into three distinct channels. Both molecular and atomic hydrogen elimination was observed, the former with significant vibrational excitation. Small yields of isomerization products, acetylene and N2, were also observed

Test accuracy of human papillomavirus in urine for detection of cervical intraepithelial neoplasia

The objective was to assess the diagnostic test accuracy of high-risk human papillomavirus (hrHPV) testing of self-collected urine and cervicovaginal samples for the detection of cervical intraepithelial neoplasia grade 2 or higher (CIN2+). We recruited a convenience sample of women 25 to 65 years of age who were undergoing clinically indicated colposcopy at two medical centers in North Carolina between November 2016 and January 2019. Women with normal cytology results and positive hrHPV results were also recruited. Urine samples, self-collected cervicovaginal samples, provider-collected cervical samples, and cervical biopsy samples were obtained from all enrolled women. Samples were tested for hrHPV DNA using the Onclarity assay (Becton Dickinson, Sparks, MD). Biopsy samples were histologically graded as CIN2+ or <CIN2. We calculated the sensitivity and specificity for detection of CIN2+ and assessed agreement between sample collection methods. We included 307 women (median age, 36 years) with valid histology results and triplematched urine, self-collected cervicovaginal, and provider-collected cervical hrHPV results; 83 women (27%) had CIN2+. Urine-based hrHPV testing correctly identified 80% of CIN2+ cases (95% confidence interval [CI], 71 to 88%) using the PCR cycle threshold (CT) established for provider-collected cervical samples, but sensitivity remained below the estimates for self-collected cervicovaginal and provider-collected cervical samples (both 94% [95% CI, 89 to 99%]). Using a higher CT cutoff value of ≤40, 90% sensitivity was achieved for urine-based hrHPV testing. Agreement between results for urine samples and self-collected cervicovaginal samples (kappa = 0.58) or provider-collected cervical samples (kappa = 0.54) was moderate. Urinebased hrHPV testing may be a promising approach to improve cervical cancer screening coverage, especially among women with limited access to health care

Extended HPV genotyping to compare hpv type distribution in self- And provider-collected samples for cervical cancer screening

Background: Primary high-risk human papillomavirus (hr- HPV) testing of self-collected cervico-vaginal swabs could increase cervical cancer screening coverage, although triage strategies are needed to reduce unnecessary colposcopies. We evaluated the use of extended hr-HPV genotyping of self-collected samples for cervical cancer screening. Methods: We recruited women ages 25-65 years at two colposcopy clinics in North Carolina between November 2016 and January 2019, and obtained self-collected cervico-vaginal samples, providercollected cervical samples, and cervical biopsies from all enrolled women. Self- and provider-collected samples were tested for 14 hr- HPV genotypes using the Onclarity Assay (Becton Dickinson). We calculated hr-HPV genotype-specific prevalence and assessed agreement between results in self- and provider-collected samples. We ranked the hr-HPV genotypes according to their positive predictive value (PPV) for the detection of cervical intraepithelial neoplasia (CIN) grade 2 or higher (CIN2+). Results: A total of 314 women participated (median age, 36 years); 85 women (27%) had CIN2+. More women tested positive for any hr-HPV on self-collected (76%) than on provider- collected samples (70%; P = 0.009) with type-specific agreement ranging from substantial to almost perfect. HPV-16 was the most common genotype in self-collected (27%) and provider-collected samples (20%), and HPV-16 prevalence was higher in self- than provider-collected samples (P < 0.001). In self- and provider-collected samples, HPV-16 had the highest PPV for CIN2+ detection. Conclusions: Overall sensitivity for CIN2+ detection was similar for both sample types, but the higher HPV-16 prevalence in self-collected samples could result in increased colposcopy referral rates. Impact: Additional molecular markers might be helpful to improve the triage of women who are hr-HPV positive on selfcollected samples

Carnauba wax nanoparticles enhance strong systemic and mucosal cellular and humoral immune responses to HIV-gp140 antigen

Induction of humoral responses to HIV at mucosal compartments without inflammation is important for vaccine design. We developed charged wax nanoparticles that efficiently adsorb protein antigens and are internalized by DC in the absence of inflammation. HIV-gp140-adsorbed nanoparticles induced stronger in vitro T-cell proliferation responses than antigen alone. Such responses were greatly enhanced when antigen was co-adsorbed with TLR ligands. Immunogenicity studies in mice showed that intradermal vaccination with HIV-gp140 antigen-adsorbed nanoparticles induced high levels of specific IgG. Importantly, intranasal immunization with HIV-gp140-adsorbed nanoparticles greatly enhanced serum and vaginal IgG and IgA responses. Our results show that HIV-gp140-carrying wax nanoparticles can induce strong cellular/humoral immune responses without inflammation and may be of potential use as effective mucosal adjuvants for HIV vaccine candidates

Quantum Symmetry and Photoreactivity of Azabenzenes

The fundamental processes associated with a photochemical reaction are described with reference to experimental properties of azabenzenes. Consideration of both excitation and relaxation processes led to presentation of the symmetry propagator, a unifying principle which maps system fluctuations (perturbations acting on an initial state) with dissipations (transitions to different states), thus directing the energy flow along competing reactive and nonreactive pathways. A coherent picture of relaxation processes including chemical reactions was constructed with the aid of spectroscopic data. Pyrazine (1,4 diazine) possesses vibronically active modes which provide an efficient mechanism for internal conversion to the first excited singlet state, where other promoting modes of the correct symmetry induce both intersystem crossing to the triplet manifold, isomerization through diaza-benzvalene, and chemical reactions through cycloreversion of dewar pyrazine to yield HCN plus an azete. At higher energies simple H atom loss and internal conversion become more predominant, leading to ring opening followed by elimination of methylene nitrile and ground state reaction products. Efficiency of chemical transformations as dissipation mechanisms versus competing fluorescence, phosphorescence and radiationless relaxation was mapped from near ultraviolet to far ultraviolet by photodissociation quantum yields into reaction channels characterized by molecular beam photofragment translational spectroscopy. A reaction path model for azabenzene photochemistry was presented and tested against experiment. Presence of undiscovered channels in other azabenzene systems was predicted and verified. The dominant process, HCN elimination, was resolved into three distinct channels. Both molecular and atomic hydrogen elimination was observed, the former with significant vibrational excitation. Small yields of isomerization products, acetylene and N2, were also observed

Soft and hard tissue healing of chronic osseous defects in the dog

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact [email protected] (M.Sc.D.)--Boston University School of Graduate Dentistry, 1972. (Periodontology)Bibliography included

Immune Cells in Cutaneous Wound Healing: A Review of Functional Data from Animal Models

The healing of skin wounds involves the activation and recruitment of various immune cell types, many of which are believed to contribute significantly to different aspects of the repair process. Roles for immune cells have been described in practically all stages of wound healing, including hemostasis, inflammation, proliferation and scar formation/remodeling. Over the last decade, tools to deplete immune cell populations in animal models have become more advanced, leading to a surge in the number of studies examining the function of specific immune cell types in skin repair. In this review, we will summarize what is known about distinct immune cell types in cutaneous wound healing, with an emphasis on data from animal studies in which specific cell types have been targeted