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Infrared (IR) action spectroscopy is utilized to characterize carbon-centered hydroperoxy-cyclohexyl radicals (·QOOH) transiently formed in cyclohexane oxidation. The oxidation pathway leads to three nearly degenerate ·QOOH isomers, β-, γ-, and δ-QOOH, which are generated in the laboratory by H-atom abstraction from the corresponding ring sites of the cyclohexyl hydroperoxide (CHHP) precursor. The IR spectral features of jet-cooled and stabilized ·QOOH radicals are observed from 3590 to 7010 cm−1 (∼10–20 kcal mol−1) at energies in the vicinity of the transition state (TS) barrier leading to OH radicals that are detected by ultraviolet laser-induced fluorescence. The experimental approach affords selective detection of β-QOOH, arising from its significantly lower TS barrier to OH products compared to γ and δ isomers, which results in rapid unimolecular decay and near unity branching to OH products. The observed IR spectrum of β-QOOH includes fundamental and overtone OH stretch transitions, overtone CH stretch transitions, and combination bands involving OH or CH stretch with lower frequency modes. The assignment of β-QOOH spectral features is guided by anharmonic frequencies and intensities computed using second-order vibrational perturbation theory. The overtone OH stretch (2νOH) of β-QOOH is shifted only a few wavenumbers from that observed for the CHHP precursor, yet they are readily distinguished by their prompt vs slow dissociation rates to OH products. [ABSTRACT FROM AUTHOR]

An IR–vacuum ultraviolet (VUV) ion-dip spectroscopy method is utilized to examine the IR spectrum of acetaldehyde oxide (CH3CHOO) in the overtone CH stretch (2νCH) spectral region. IR activation creates a depletion of the ground state population that reduces the VUV photoionization signal on the parent mass channel. IR activation of the more stable and populated syn-CH3CHOO conformer results in rapid unimolecular decay to OH + vinoxy products and makes the most significant contribution to the observed spectrum. The resultant IR–VUV ion-dip spectrum of CH3CHOO is similar to that obtained previously for syn-CH3CHOO using IR action spectroscopy with UV laser-induced fluorescence detection of OH products. The prominent IR features at 5984 and 6081 cm−1 are also observed using UV + VUV photoionization of OH products. Complementary theoretical calculations utilizing a general implementation of second-order vibrational perturbation theory provide new insights on the vibrational transitions that give rise to the experimental spectrum in the overtone CH stretch region. The introduction of physically motivated small shifts of the harmonic frequencies yields remarkably improved agreement between experiment and theory in the overtone CH stretch region. The prominent features are assigned as highly mixed states with contributions from two quanta of CH stretch and/or a combination of CH stretch with an overtone in mode 4. The generality of this approach is demonstrated by applying it to three different levels of electronic structure theory/basis sets, all of which provide spectra that are virtually indistinguishable despite showing large deviations prior to introducing the shifts to the harmonic frequencies. [ABSTRACT FROM AUTHOR]

The oxidation of cycloalkanes is important in the combustion of transportation fuels and in atmospheric secondary organic aerosol formation. A transient carbon-centered radical intermediate (•QOOH) in the oxidation of cyclohexane is identified through its infrared fingerprint and time-and energy-resolved unimolecular dissociation dynamics to hydroxyl (OH) radical and bicyclic ether products. Although the cyclohexyl ring structure leads to three nearly degenerate •QOOH isomers (β-, γ-, and δ-QOOH), their transition state (TS) barriers to OH products are predicted to differ considerably. Selective characterization of the β-QOOH isomer is achieved at excitation energies associated with the lowest TS barrier, resulting in rapid unimolecular decay to OH products that are detected. A benchmarking approach is employed for the calculation of high-accuracy stationary point energies, in particular TS barriers, for cyclohexane oxidation (C6H11O2), building on higher-level reference calculations for the smaller ethane oxidation (C2H5O2) system. The isomer-specific characterization of β-QOOH is validated by comparison of experimental OH product appearance rates with computed statistical microcanonical rates, including significant heavy-atom tunneling, at energies in the vicinity of the TS barrier. Master-equation modeling is utilized to extend the results to thermal unimolecular decay rate constants at temperatures and pressures relevant to cyclohexane combustion. [ABSTRACT FROM AUTHOR]

Fourteen highly reactive isomers of C5H and their ionic counterparts have been theoretically investigated using density functional theory (DFT) and coupled-cluster methods. The linear C5H (l-C5H) radical, pent-1,3-diyn-5-yliden-1-yl (1), along with its cationic form and the cyclic C5H (c-C5H), 1-ethynylcycloprop-1-en-2-yl-3-ylidene (2), have recently been detected in the Taurus Molecular Cloud-1. By using the UCCSD(T)/cc-pCVTZ level of theory, the calculated rotational constants and other spectroscopic parameters are found to be in good agreement with the available experimental data for isomers 1 and 2. Therefore, the current theoretical study may assist synthetic chemists and molecular spectroscopists in detecting other isomers in the laboratory or in the interstellar medium (ISM). Thermodynamically favorable rearrangement schemes for forming low-lying isomers 1, 2, and 3 have also been studied theoretically, and (2λ3-cycloprop-2-en-1-ylidene)ethenylidene (3) with a large dipole moment (μ = 4.73 Debye) is proposed to be a plausible candidate for detection in the ISM. [ABSTRACT FROM AUTHOR]

Simple Summary: Tetra-coordinated carbon-containing molecules generally form tetrahedral carbon geometries. However, there are continuous searches for other possible geometries of tetra-coordinated carbon which are non-classical in nature. However, planar tetra-coordinated carbon (ptC), where all four bonds of the carbon atom are in the same plane or the pyramidane structure in which tetra-coordinated carbon with all four bonds are on the same side of a plane, are good examples of non-classical structures. However, synthesis and experimental realization of these molecules are very challenging in the laboratory. In this paper, we have theoretically investigated nine unusual isomers of the molecular formula C5H4 and studied their stability and novel bonding patterns. One of the ptC compounds has been found to be thermodynamically more stable compared to its tetrahedral counterpart with a high value of dipole moment (μ = 4.64 D), which may be helpful for experimental detection in the laboratory or in the low-temperature regions of the interstellar medium. We have theoretically investigated nine unusual isomers of the molecular formula C5H4 using coupled cluster (CC) and density functional theory (DFT) methods. These molecules possess non-classical structures consisting of two pyramidanes, three planar tetracoordinate carbon (ptC), and four spiro types of isomers. Both the pyramidanes (tetracyclo-[2.1.0.01,3.02,5]pentane; py-1 and tricyclo-[2.1.0.02,5]pentan-3-ylidene; py-2) are minima on the potential energy surface (PES) of C5H4. Among the three isomers containing ptC, (SP4)-spiro [2.2]pent-1-yne (ptC-2) is a minimum, whereas isomer, (SP4)-spiro [2.2]pent-1,4-diene (ptC-1) is a fourth-order saddle point, and (SP4)-sprio[2.2]pent-1,4-diylidene (ptC-3) is a transition state. The corresponding spiro isomers spiro[2.2]pent-1,4-diene (spiro-1), sprio[2.2]pent-1,4-diylidene (spiro-3) and spiro[2.2]pent-4-en-1-ylidene (spiro-4) are local minima, except spiro[2.2]pent-1-yne (spiro-2), which is a second-order saddle point. All relative energies are calculated with respect to the global minimum (pent-1,3-diyne; 1) at the CCSD(T)/cc-pVTZ level of theory. Quantum chemical calculations have been performed to analyze the bonding and topological configurations for all these nine isomers at the B3LYP/6-311+G(d,p) level of theory for a better understanding of their corresponding electronic structures. ptC-2 was found to be thermodynamically more stable than its corresponding spiro counterpart (spiro-2) and possesses a high dipole moment (μ = 4.64 D). The stability of the ptC structures with their higher spin states has been discussed. [ABSTRACT FROM AUTHOR]

Drug discovery is still behind in the race compared to vaccine discovery in fighting COVID-19. In this study, we have selected 41 quinazoline alkaloids from two natural product databases to create an adequate library and performed detailed computational studies against the main protease ( M pro ) of SARS-CoV-2 using two reference compounds, namely famotidine and X77. The screening of the library was carried out by blending the rigid docking and pharmacokinetic analysis that resulted in nine alkaloids as initial leads against M pro . These initial leads were further subjected to advanced flexible docking and were compared with reference compounds (famotidine and X77) for the analysis of structure-based interactions. For further selection, a second screening was carried out based on binding energies and interaction profiles that yielded three alkaloids, namely CNP0416047, 3-hydroxy anisotine and anisotine as final leads. The stereo-electronic features of lead alkaloids were further investigated through additional E-pharmacophore mapping against crystallized X77 reference compound. Additionally, the reactivity of lead alkaloids at the binding sites of the protein was estimated by measuring the electron distribution on the frontier molecular orbitals and HOMO–LUMO band energies. Finally, the stabilities of complexes between lead alkaloids with the protein were accessed extensively using robust molecular dynamics simulation through RMSD, RMSF, Rg and MM-PBSA calculation. Thus, this study identifies three natural quinazoline alkaloids as potential lead inhibitors of M pro through extensive computational analysis. This study performed a full-scale in silico investigations on natural quinazoline alkaloids against the main protease (MPro) of SARS_CoV_2 by examining forty one natural quinazoline alkaloids and identified three alkaloids (CNP0416047, 3-hydroxy anisotine and anisotine) as final lead compounds. The screening and structure-based analysis of these ligands were carried out by blending different computational techniques such as rigid docking, pharmacokinetics, flexible docking, E-pharmacophore mapping, DFT studies and MD simulations. Mostly, this study added values to quinazoline alkaloids which are fascinating natural pharmacophores and opened the possibilities of in vitro studies of these hit alkaloids in future. [ABSTRACT FROM AUTHOR]

We have studied the intermolecular complex formation between trifluoromethoxybenzene and methanol (CD3OD) in superfluid helium droplets by infrared spectroscopy in the spectral range of 2630–2730 cm−1, covering the O–D stretches of methanol-d4 (CD3OD). The cluster size associated with the observed bands is deduced from the variation of infrared intensity of a particular band with the partial pressures of trifluoromethoxybenzene and methanol. Quantum chemical calculations are performed at the MP2/6-311++G(d,p) level of theory to complement the experimental results. As a result, we have identified six different conformers of the trifluoromethoxybenzene⋯methanol intermolecular complex: three bound via O–H⋯O hydrogen bonds and the other three via O–H⋯π hydrogen bonds. Furthermore, to access the effect of fluorination on the methyl unit of anisole molecules, we compare the IR spectrum of trifluoromethoxybenzene (C6H5OCF3)⋯methanol with our earlier reported spectrum of anisole (C6H5OCH3)⋯methanol. [ABSTRACT FROM AUTHOR]

The mass-selective infrared (IR) spectra of oxazole-(D2O)n≤2 complexes embedded in helium droplets are recorded in the spectral range of 2565–2800 cm−1. The experimental IR spectra are assigned by comparing with quantum chemical calculations at the MP2/6-311++G(d,p) level of theory. Here, we show that in the case of the 1:1 oxazole-D2O dimer, the water molecule binds to the N atom of the heterocyclic ring via a N⋯DO hydrogen bond (H-bond). However, in the oxazole-(D2O)2 trimer, the water dimer forms N⋯DO and CH⋯O H-bonds with the N atom and adjacent CH group, respectively, leading to the formation of a seven-membered ring. We compare these results with those of our recently reported isoxazole-(water)n≤2 complexes to demonstrate differences in the hydration motif of these two structural isomers. [ABSTRACT FROM AUTHOR]

Hydration of aromatic molecules is a fundamental chemical process. Herein, microhydration framework of the prototypical neutral polycyclic aromatic hydrocarbon (PAH), naphthalene (naphthalene–(water)n≤3), is investigated by infrared spectroscopy inside helium nanodroplets. The measured data are analyzed by quantum chemical calculations at the MP2/6-311++G(d,p) level. This combined experimental and theoretical approach demonstrates that water binds to the naphthalene ring via π hydrogen bond (H-bond) for n = 1 case. Further addition of the solvent molecules occurs via the formation of a H-bonded water network facilitated by the nonadditive cooperative force. No isomers are observed in which the solvent molecules separately bind to the aromatic ring. For n = 3 case, we observe the formation of a cyclic H-bonded water moiety. Comparison with corresponding cationic and anionic naphthalene±–(water)n clusters demonstrates the charge-induced modification of the hydration motif. Our results are further compared with the prototypical benzene–(water)n complexes to comprehend the effect of an additional phenyl ring on the solvation network. [ABSTRACT FROM AUTHOR]

Abstract Background Targeted interventions (TIs) have been a major strategy for HIV prevention in India. We evaluated the impact of TIs on HIV prevalence in high HIV prevalence southern states (Tamil Nadu, Karnataka, Andhra Pradesh and Maharashtra). Methods A quasi-experimental approach was used to retrospectively compare changes in HIV prevalence according to the intensity of targeted intervention implementation. Condom gap (number of condoms required minus condoms supplied by TIs) was used as an indicator of TI intensity. Annual average number of commercial sex acts per female sex worker (FSW) reported in Behavioral Surveillance Survey was multiplied by the estimated number of FSWs in each district to calculate annual requirement of condoms in the district. Data of condoms supplied by TIs from 1995 to 2008 was obtained from program records. Districts in each state were ranked into quartiles based on the TI intensity. Primary data of HIV Sentinel Surveillance was analyzed to calculate HIV prevalence reductions in each successive year taking 2001 as reference year according to the quartiles of TI intensity districts using generalized linear model with logit link and binomial distribution after adjusting for age, education, and place of residence (urban or rural). Results In the high HIV prevalence southern states, the number of TI projects for FSWs increased from 5 to 310 between 1995 and 2008. In high TI intensity quartile districts (n = 30), 186 condoms per FSW/year were distributed through TIs as compared to 45 condoms/FSW/year in the low TI intensity districts (n = 29). Behavioral surveillance indicated significant rise in condom use from 2001 to 2009. Among FSWs consistent condom use with last paying clients increased from 58.6% to 83.7% (p < 0.001), and among men of reproductive age, the condom use during sex with non-regular partner increased from 51.7% to 68.6% (p < 0.001). A significant decline in HIV and syphilis prevalence has occurred in high prevalence southern states among FSWs and young antenatal women. Among young (15-24 years) antenatal clinic attendees significant decline was observed in HIV prevalence from 2001 to 2008 (OR = 0.42, 95% CI 0.28-0.62) in high TI intensity districts whereas in low TI intensity districts the change was not significant (OR = 1.01, 95% CI 0.67-1.5). Conclusion Targeted interventions are associated with HIV prevalence decline.

Anisole is a multifunctional molecule that can form intermolecular complexes via its aromatic π-electron system as well as its methoxy group. We have studied the complexation of anisole with methanol. This serves as a prototype system to explore the competition between O–H⋯O, O–H⋯π, C–H⋯O and C–H⋯π hydrogen bonding. The anisole⋯methanol molecular complexes were formed in superfluid helium droplets and were detected using high-resolution laser-infrared spectroscopy, in the frequency range between 2630 and 2730 cm−1 covering the O–D stretches of methanol-d4 (CD3OD). Several bands assigned to (anisole)m⋯(methanol)n complexes (where m = 1, and 2 and n = 1) were observed. The experimental results are complemented by the ab initio electronic structure calculations at the MP2/6-311++G(d,p) and B3LYP-D3/aug-cc-pVTZ levels of theory. Based on a comparison of the observed spectra with the ab initio theoretical spectra, we suggest that for the anisole⋯methanol complex, structures bound via O–H⋯O and O–H⋯π hydrogen bonding are almost equally preferred. [ABSTRACT FROM AUTHOR]

Abstract: The first example of a chiral cinchona‐squaramide catalyzed enantioselective intramolecular aza‐Michael addition for the synthesis of dihydroisoquinolines and tetrahydropyridines has been developed. In general, good yields and excellent enantioselctivities were observed. Broad classes of Michael acceptors, such as enones, esters, thioesters, and Weinreb amides, were successful substrates. The possibility of recycling the catalysts has also been demonstrated. An oxidation of combined enamine and keto functionalities on chiral dihydroisoquinolines leads to a single diastereomer of an architecturally unprecedented tetracyclic core without loss in enantioselectivity. [ABSTRACT FROM AUTHOR]

In this study 1155 injection drug users (IDUs) receiving targeted intervention in five cities of Punjab were surveyed; three cities (Amritsar, Taran-Taran, Batala) were in districts sharing an international border with Pakistan and the other two were Jalandhar and Ludhiana. Information on socio-demography, substance use and sexual practices were collected; blood samples were tested for biologic markers. HIV and HCV antibody (HCVAb) prevalences in injection drug users were 29 and 49%, respectively. Of the HCVAb-seroreactive IDUs, 33% had HIV as well. HIV prevalence in young IDUs (≤19 years), estimated as surrogate for HIV incidence, was high at 12% and HCVAb in this subgroup was 27%. Herpes simplex virus 2 antibody (IgG) was detected in 10% of IDUs; 2% had syphilis. Alcohol use prevalence was high and frequency of use concerning. In multivariate analyses, ‘city of residence closer to international border’ and ‘>1 year duration of injecting drugs were associated with HIV and HCVAb. Furthermore, ‘irregular supply of syringes and needles’ was associated with HCVAb seroreactive status of IDUs (adjusted odds ratio 1.7; 95% CI 1.3–2.3; P < 0.001), and ‘any genital disease symptom within the last year’ (adjusted odds ratio 2; 95% CI 1.4–2.9; P < 0.001) was associated with HIV infection. Alcohol and sexual risk reduction, strengthening of needle–syringe exchange, reducing injecting duration and clinical management of HIV, HCV and HIV/HCV co-infection appear as four core programme needs. [ABSTRACT FROM PUBLISHER]

An attempt is made to understand the correlates of anaemia and examine the response to iron supplementation in some selected villages in West Bengal where anaemia among women is high. Estimates are derived by cyanmethemoglobin method to determine correlates of anaemia. Changes in haemoglobin after oral iron supplementation among women were monitored. Relationships among the variables were analyzed using the SPSS version 14.0 software. Analysis of various micro-level factors demonstrate that women who suffer from severe to moderate anaemia differ considerably in terms of socio-economic, dietary and anthropometric measurements from women who experience moderate to normal levels of anaemia. The lowest haemoglobin level was noticed among the <30 year old women. This is the child bearing and rearing period, making them more prone to anaemia. High rates of live births, heavy workload, poor diet and menstrual disorder are probably responsible for this anaemic condition among women. Uniform improvement in haemoglobin concentration after iron supplementation was not found among women who were at different levels of anaemia before iron supplementation. [ABSTRACT FROM AUTHOR]

Background & objectives: Mizoram, a northeastern State of India bordering Myanmar, is home to several tribal clans under the ethnic group Mizo: Renthelei, Ralte, Paite, Lai, Hmar, Lusei, Mara, Thado and Kuki. Mizos also reside in the neighbouring northeastern States of Tripura, Assam, Manipur and Nagaland. The majority of Mizo people outside India live across the border in the neighbouring Chin State and Sagaing Region of Myanmar. Over the last decade, Mizoram witnessed a concerning level of rise in HIV prevalence among the general population. The present rapid review was conducted to identify various interventions that could help curb this rising trend. Methods: An electronic search strategy with broad domains of ‘HIV/AIDS’, ‘key population’, ‘community engagement’ and ‘interventions in Mizoram’ using PubMed, Embase and Cochrane was adopted; grey literature were also accessed. Evidence, thus gleaned, were synthesized. Results: Twenty eight resource materials comprising articles, reports and dissertations contributed to the current review. Changing tribal social support structure, early initiation of drugs, sexual debut at an early age and drug–sex interface were identified as factors associated with the progression of HIV epidemic in the State. Issues pertaining to the migration of people across the borders and easy access to drugs continue to be of concern. Churches and youth leaders have a strong influence on the society, at times even constraining access of key population groups to HIV prevention and care services. Tackling stigma and discrimination, ensuring uninterrupted HIV services and creation of an enabling environment in this context seems urgently needed. Incarcerated people in the State have been found with a high level of HIV infection and their linkages with prevention and care services need strengthening. Interpretation & conclusions: This review underscores the importance of drawing upon successful intervention examples from the past such as ‘Friends on Friday’ and Red Ribbon Clubs. Active engagement of community-based organizations in programme planning, implementation and monitoring is essential. Establishment of harm reduction interventions for general and key populations paired with strategic communication appear to be the need of the hour. [ABSTRACT FROM AUTHOR]

We investigate glycine microsolvation with water molecules, mimicking astrophysical conditions, in our laboratory by embedding these clusters in helium nanodroplets at 0.37 K. We recorded mass selective infrared spectra in the frequency range 1500-1800  cm-1 where two bands centered at 1630 and 1724 cm-1 were observed. By comparison with the extensive accompanying calculations, the band at 1630 cm-1 was assigned to the COO- asymmetric stretching mode of the zwitter ion and the band at 1724 cm-1 was assigned to redshifted C=O stretch within neutral clusters. We show that zwitter ion formation of amino acids readily occurs with only few water molecules available even under extreme conditions. [ABSTRACT FROM AUTHOR]

The oxidation of cycloalkanes is important in the combustion of transportation fuels and in atmospheric secondary organic aerosol formation. A transient carbon-centered radical intermediate (•QOOH) in the oxidation of cyclohexane is identified through its infrared fingerprint and time- and energy-resolved unimolecular dissociation dynamics to hydroxyl (OH) radical and bicyclic ether products. Although the cyclohexyl ring structure leads to three nearly degenerate •QOOH isomers (β-, γ-, and δ-QOOH), their transition state (TS) barriers to OH products are predicted to differ considerably. Selective characterization of the β-QOOH isomer is achieved at excitation energies associated with the lowest TS barrier, resulting in rapid unimolecular decay to OH products that are detected. A benchmarking approach is employed for the calculation of high-accuracy stationary point energies, in particular TS barriers, for cyclohexane oxidation (C 6 H 11 O 2 ), building on higher-level reference calculations for the smaller ethane oxidation (C 2 H 5 O 2 ) system. The isomer-specific characterization of β-QOOH is validated by comparison of experimental OH product appearance rates with computed statistical microcanonical rates, including significant heavy-atom tunneling, at energies in the vicinity of the TS barrier. Master-equation modeling is utilized to extend the results to thermal unimolecular decay rate constants at temperatures and pressures relevant to cyclohexane combustion., Competing Interests: Competing interests statement:D.E.H. participated in a Faraday Discussion on Unimolecular Reactions and published general discussions with several co-authors within the last 4 y. The authors declare no other potential conflicts of interest.

Considering the importance of magnesium-bearing hydrocarbon molecules (MgC n H; n = 2, 4, and 6) in the carbon-rich circumstellar envelopes (e.g., IRC+10216), a total of 28 constitutional isomers of MgC 4 H have been theoretically investigated using density functional theory (DFT) and coupled-cluster methods. The zero-point vibrational energy corrected relative energies at the ROCCSD(T)/cc-pCVTZ level of theory reveal that the linear isomer, 1-magnesapent-2,4-diyn-1-yl ( 1 , 2 Σ + ), is the global minimum geometry on the MgC 4 H potential energy surface. The latter has been detected both in the laboratory and in the evolved carbon star, IRC+10216. The calculated spectroscopic data for 1 match well with the experimental observations (error ∼ 0.78%) which validates our theoretical methodology. Plausible isomerization processes happening among different isomers are examined using DFT and coupled-cluster methods. CASPT2 calculations have been performed for a few isomers exhibiting multireference characteristics. The second most stable isomer, 1-ethynyl-1λ 3 -magnesacycloprop-2-ene-2,3-diyl ( 2 , 2 A 1 , μ = 2.54 D), is 146 kJ mol -1 higher in energy than 1 and possibly the next promising candidate to be detected in the laboratory or in the interstellar medium in future.

Introduction: Mizoram, the northeastern State of India bordering Myanmar, is presently witnessing a burgeoning generalized HIV epidemic along with the highest State-level HIV prevalence among female sex workers (FSWs, 24.7%) and people who inject drugs (PWID,19.8%) in the country. The present study was conducted against such background to understand the current situation of HIV prevention and care services in Mizoram, and capture community voices as well as concerns so that the way forward could be informed appropriately., Methods: The study period was October through December 2020 (in the midst of COVID-restrictions) in the districts of Aizawl, Mamit, Kolasib, Lunglei, and Champhai where HIV prevalence crossed 1% among ante-natal clinic (ANC) attending women. Contrastingly, the national average HIV prevalence among ANC attendees is 0.24%, which formed the basis for selecting the aforementioned five high burden districts for this current inquiry. In-depth-interviews were conducted with community members and youth leaders, vulnerable and general population groups as well as HIV-program officials. Interviews were recorded, transcribed, translated and later coded for analysis following thematic approach., Results: The emerging issues were grouped in three thematic layers; (1) HIV vulnerability, (2) challenges pertaining to prevention and care services, and (3) program elements and future roadmap. Discrimination at the community level, unfriendly behavior of some of the HIV-service staff, occasional interruption in supplies of anti-retroviral treatment and sterile syringes and needles were voiced as deterrents to accessing HIV prevention and care services by the participants. Community engagement, based on restorative approach rather than retribution and ensuring enhanced performance of the district AIDS program control units emerged as necessary programmatic elements., Conclusion: This inquiry highlighted macro-social and structural forces contributing to stigma and discrimination toward people at risk of HIV. It is urgent that HIV-services are re-aligned through de-centralized district level innovations and creation of safer spaces at the physical, societal and familial level. These, even during the time of stress such as a pandemic, would help health services to remain resilient. HIV outreach, sensitization of the community leaders and health-care professionals through strategic communication and ownership of the communities in these endeavors appeared paramount., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Rao, Mamulwar, Panda, Pachuau, Vanlalvenzuali, Lalruatsanga, Roy and Lalnuntlangi.)

Polycyclic aromatic hydrocarbons are considered as primary carriers of the unidentified interstellar bands. The recent discovery of the first interstellar aromatic molecule, benzonitrile (C 6 H 5 CN), suggests a repository of aromatic hydrocarbons in the outer earth environment. Herein, we report an infrared (IR) study of benzonitrile-(D 2 O) n clusters using mass-selective detection in helium nanodroplets. In this work, we use isotopically substituted water, D 2 O, instead of H 2 O because of our restricted IR frequency range (2565-3100 cm -1 ). A comparison of the experimental and predicted spectra computed at the MP2/6-311++G(d,p) level of benzonitrile-(water) 1-2 clusters reveals the formation of a unique local minimum structure, which was not detected in previous gas-phase molecular beam experiments. Here, the solvent water forms a nearly linear hydrogen bond (H-bond) with the nitrile nitrogen of benzonitrile, while the previously reported most stable cyclic H-bonded isomer is not observed. This can be rationalized by the stepwise aggregation process of precooled monomers. The addition of a second water molecule results in the formation of two different isomers. In one of the observed isomers, a H-bonded water chain binds linearly to the nitrile nitrogen similar to the monohydrated benzonitrile-water complex. In the other observed isomer, the water dimer forms a ring-type structure, where a H-bonded water dimer simultaneously interacts with the nitrile nitrogen and the adjacent ortho CH group. Finally, we compare the water-binding motif in the neutral benzonitrile-water complex with the corresponding positively and negatively charged benzonitrile-water monohydrates to comprehend the charge-induced alteration of the solvent binding motif.

Hydration of aromatic molecules is a fundamental chemical process. Herein, microhydration framework of the prototypical neutral polycyclic aromatic hydrocarbon (PAH), naphthalene (naphthalene-(water)n≤3), is investigated by infrared spectroscopy inside helium nanodroplets. The measured data are analyzed by quantum chemical calculations at the MP2/6-311++G(d,p) level. This combined experimental and theoretical approach demonstrates that water binds to the naphthalene ring via π hydrogen bond (H-bond) for n = 1 case. Further addition of the solvent molecules occurs via the formation of a H-bonded water network facilitated by the nonadditive cooperative force. No isomers are observed in which the solvent molecules separately bind to the aromatic ring. For n = 3 case, we observe the formation of a cyclic H-bonded water moiety. Comparison with corresponding cationic and anionic naphthalene±-(water)n clusters demonstrates the charge-induced modification of the hydration motif. Our results are further compared with the prototypical benzene-(water)n complexes to comprehend the effect of an additional phenyl ring on the solvation network.

Hydration of heterocyclic molecules plays a crucial role in biological and chemical recognition. Here, we present an infrared (IR) spectroscopic investigation of microhydrated, heterocyclic isoxazole molecule. The IR spectra of isoxazole-(water) n ≤2 clusters are recorded using helium nanodroplet spectroscopy and are analyzed by quantum chemical calculations at the MP2/6-311++g(d,p) level. In the most abundant isoxazole-water dimer, the solvent water participates in a N···HO hydrogen bonding (H-bond) interaction, while in another observed structure, water simultaneously interacts with ring nitrogen and the neighboring CH group via N···HO and CH···O H-bonds. The addition of another water molecule to the monohydrated cluster results in the formation of a single isomer that features a seven-membered ring, in which the water dimer simultaneously interacts with skeletal nitrogen and the adjacent CH group through N···HO and CH···O bonds.

Isomers of C 11 H 8 have been theoretically examined using density functional theory and coupled-cluster methods. The current investigation reveals that 2 a H-cyclopenta[ cd ]indene ( 2 ), 7-ethynyl-1H-indene ( 6 ), 4-ethynyl-1H-indene ( 7 ), 6-ethynyl-1 H -indene ( 8 ), 5-ethynyl-1 H -indene ( 9 ), and 7b H -cyclopenta[ cd ]indene ( 10 ) remain elusive till date in the laboratory. The puckered low-lying isomer 2 lies at 9 kJ mol -1 below the experimentally known molecule, cyclobuta[ de ]naphthalene ( 3 ), at the fc-CCSD(T)/cc-pVTZ//fc-CCSD(T)/cc-pVDZ level of theory. 2 lies at 36 kJ mol -1 above the thermodynamically most stable and experimentally known isomer, 1H-cyclopenta[ cd ]indene ( 1 ), at the same level. It is identified that 1,2-H transfer from 1 yields 2 H -cyclopenta[ cd ]indene ( 14 ) and subsequent 1,2-H shift from 14 yields 2 . Appropriate transition states have been identified, and intrinsic reaction coordinate calculations have been carried out at the B3LYP/6-311+G(d,p) level of theory. Recently, 1-ethynyl-1 H -indene ( 11 ) has been detected using synchrotron-based vacuum ultraviolet ionization mass spectrometry. 2-Ethynyl-1 H -indene ( 4 ) and 3-ethynyl-1 H -indene ( 5 ) have been synthetically characterized in the past. While the derivatives of 7b H -cyclopenta[ cd ]indene ( 10 ) have been isolated elsewhere, the parent compound remains unidentified till date in the laboratory. Although C 11 H 8 is a key elemental composition of astronomical interest for the formation of polycyclic aromatic hydrocarbons in the interstellar medium, none of its low-lying isomers have been characterized by rotational spectroscopy though they are having a permanent dipole moment (μ ≠ 0). Therefore, energetic and spectroscopic properties have been computed, and the present investigation necessitates new synthetic studies on C 11 H 8 , in particular 2 , 6-10 , and also rotational spectroscopic studies on all low-lying isomers.

Background: Targeted interventions (TIs) have been a major strategy for HIV prevention in India. We evaluated the impact of TIs on HIV prevalence in high HIV prevalence southern states (Tamil Nadu, Karnataka, Andhra Pradesh and Maharashtra)., Methods: A quasi-experimental approach was used to retrospectively compare changes in HIV prevalence according to the intensity of targeted intervention implementation. Condom gap (number of condoms required minus condoms supplied by TIs) was used as an indicator of TI intensity. Annual average number of commercial sex acts per female sex worker (FSW) reported in Behavioral Surveillance Survey was multiplied by the estimated number of FSWs in each district to calculate annual requirement of condoms in the district. Data of condoms supplied by TIs from 1995 to 2008 was obtained from program records. Districts in each state were ranked into quartiles based on the TI intensity. Primary data of HIV Sentinel Surveillance was analyzed to calculate HIV prevalence reductions in each successive year taking 2001 as reference year according to the quartiles of TI intensity districts using generalized linear model with logit link and binomial distribution after adjusting for age, education, and place of residence (urban or rural)., Results: In the high HIV prevalence southern states, the number of TI projects for FSWs increased from 5 to 310 between 1995 and 2008. In high TI intensity quartile districts (n = 30), 186 condoms per FSW/year were distributed through TIs as compared to 45 condoms/FSW/year in the low TI intensity districts (n = 29). Behavioral surveillance indicated significant rise in condom use from 2001 to 2009. Among FSWs consistent condom use with last paying clients increased from 58.6% to 83.7% (p < 0.001), and among men of reproductive age, the condom use during sex with non-regular partner increased from 51.7% to 68.6% (p < 0.001). A significant decline in HIV and syphilis prevalence has occurred in high prevalence southern states among FSWs and young antenatal women. Among young (15-24 years) antenatal clinic attendees significant decline was observed in HIV prevalence from 2001 to 2008 (OR = 0.42, 95% CI 0.28-0.62) in high TI intensity districts whereas in low TI intensity districts the change was not significant (OR = 1.01, 95% CI 0.67-1.5)., Conclusion: Targeted interventions are associated with HIV prevalence decline.

Following our earlier work [Phys. Rev. Lett. 84, 3570 (2000)] we present an exact linear stability analysis of one-site monochromatic breathers in a piecewise smooth discrete nonlinear Schrödinger-type model. Destabilization of the breather occurs by virtue of a growth rate becoming positive as a stability border is crossed, while above a critical spatial decay rate (lambda(c)) the breather is found to be intrinsically unstable. The model admits of other exact breather solutions, including multisite monochromatic breathers for which the profile variable (phi(n)) crosses a relevant threshold at more than one site. In particular, we consider exact two-site breather solutions with phase difference delta between the two sites above threshold, and present stability results for delta=pi (antiphase breather; the in-phase breather with delta=0 happens to be intrinsically unstable). We obtain a band of extended eigenmodes, together with a pair of localized symmetric modes and another pair of localized antisymmetric ones. The frequencies of the localized modes vary as the parameters characterizing the breather are made to vary, and destabilization occurs through the Krein collision of a quartet of growth rates, leading to temporal growth of a pair of symmetric eigenmodes of nonzero frequency. We clarify the limit N--> infinity (N is the gap length between the sites above threshold) when the two-site breather reduces to a pair of decoupled one-site breathers. The model offers the possibility of obtaining spatially random vortex-type breathers.