What puts them at risk? A cross-sectional case-control survey of demographic profile and sexual behavior of patients with sexually transmitted infections at a tertiary care center in North India.

BACKGROUND: Sexually transmitted infections (STIs) are a major public health problem in developing nations. Identification of risk factors can help in formulating effective strategies against them. The present study was conducted in a tertiary care hospital in North India over 1 year to identify the risk factors associated with STIs. MATERIALS AND METHODS: A questionnaire-based cross-sectional case-control survey was conducted where participants answered questions on demographic details, sexual behavior, and awareness of STIs. Cases were patients with STIs whereas controls were randomly selected from healthy individuals accompanying patients with nonvenereal complaints attending our hospital. RESULTS: There were 106 cases and 64 controls. STI patients had sexual debut 2 years before controls. A higher proportion of STI cases had lower education, multiple sexual partners, lived separately from their partner, had nonregular partners, had protected sex in the last month, had sex under influence of alcohol/illicit drugs, sex in unstructured settings, and engaged in transactional sex, in comparison to controls (P < 0.05). More cases were aware of the symptoms/preventive measures of STIs (P < 0.001). On multivariate analysis, multiple sexual partners, sex under influence of alcohol/illicit drugs with nonregular partner, protected sex in the last month, and knowledge of preventive measures were found to be statistically associated with STIs (P < 0.05). CONCLUSIONS: Our study identifies risk-behavior patterns in patients with STIs, which should be modified to reduce the burden of these diseases. Increasing the knowledge about STIs in these patients can translate into more common condom usage that lends support for strengthening sexual health programs at grass-root levels. LIMITATIONS: The small size of the study population could have led to decreased power of the study to detect differences between cases and controls. The external validity of our results needs to be tested in different population groups involving larger sample sizes.

High Q factor InP photonic crystal nanobeam cavities on silicon wire waveguides.

High-quality (Q) factor indium phosphide (InP)-based 1D photonic crystal nanobeam cavities are fabricated on silicon on insulator waveguides. Through the optimization of the fabrication process, the intrinsic Q factor of these fully encapsulated nanocavities is demonstrated to attain values higher than 100,000. Experimental and numerical investigations are carried out on the impact, on the Q factor, of the strength of the evanescent wave coupling between the cavity and the waveguide. We reveal that this coupling can result in a modification of the electromagnetic field distribution in the resonant mode, which gives rise up to a factor 4 reduction in the intrinsic Q factor for the structures under study.

Integrated III-V Photonic Crystal--Si waveguide platform with tailored optomechanical coupling.

Optomechanical systems, in which the vibrations of a mechanical resonator are coupled to an electromagnetic radiation, have permitted the investigation of a wealth of novel physical effects. To fully exploit these phenomena in realistic circuits and to achieve different functionalities on a single chip, the integration of optomechanical resonators is mandatory. Here, we propose a novel approach to heterogeneously integrate arrays of two-dimensional photonic crystal defect cavities on top of silicon-on-insulator waveguides. The optomechanical response of these devices is investigated and evidences an optomechanical coupling involving both dispersive and dissipative mechanisms. By controlling the optical coupling between the waveguide and the photonic crystal, we were able to vary and understand the relative strength of these couplings. This scalable platform allows for an unprecedented control on the optomechanical coupling mechanisms, with a potential benefit in cooling experiments, and for the development of multi-element optomechanical circuits in the framework of optomechanically-driven signal-processing applications.

Subduing surface recombination for continuous-wave operation of photonic crystal nanolasers integrated on Silicon waveguides.

Detrimental surface recombination of carriers in InP-based photonic crystal nanobeams containing quantum wells is reduced by employing chemical treatment followed by silica encapsulation. Carrier lifetime is shown to recover to 2.63ns close to the bulk value. This enables us to obtain optically pumped room-temperature continuous-wave nanolasers at 1.55µm integrated onto Silicon on insulator waveguide platform with a threshold of 8µW.

Intralesional injection of Mycobacterium w vaccine vs imiquimod, 5%, cream in patients with anogenital warts: a randomized clinical trial.

IMPORTANCE: Intralesional antigen therapy has been used in the treatment of anogenital warts (AGWs), but it has not been compared with existing therapies. Evidence of its efficacy is not strong. OBJECTIVE: To compare the efficacy and safety of intralesional Mycobacterium w (Mw) vaccine with that of imiquimod, 5%, cream in the treatment of AGWs, as well as changes in human papillomavirus (HPV)-6 and HPV-11 viral loads. DESIGN, SETTING, AND PARTICIPANTS: A double-blind randomized clinical trial was conducted in New Delhi, India, between February 2009 and July 2012 and included a 3-month follow-up. Of 159 patients with AGWs who were screened, 89 were randomized. INTERVENTIONS: Patients received either imiquimod, 5%, cream and an intralesional vehicle (imiquimod group: 44 patients) or vehicle cream and intralesional Mw vaccine (Mw group: 45 patients). MAIN OUTCOMES AND MEASURES: The primary end point was complete clinical remission of visible AGWs. Secondary measures included the percentage of reduction in the surface area of AGWs and viral load for HPV-6 and HPV-11. Viral load was measured by real-time quantitative polymerase chain reaction. RESULTS: In the intention-to-treat analysis, 59% (n = 26) of the patients in the imiquimod group and 67% (n = 30) of those in the Mw group had complete resolution (P = .52). Eighteen HPV genotypes, including high-risk genotypes, were detected, with no significant differences between the treatment groups (all P > .05). There was a significant decline in the mean viral loads of HPV-6 (from 0.011 × 108 to 0.00000154 × 108 copies/mg of tissue; P = .003) and HPV-11 (from 0.121 × 108 to 0.017 × 108 copies/mg of tissue; P = .03) after treatment in the Mw group but only in the viral load of HPV-6 (from 1.41 × 108 to 0.004 × 108 copies/mg of tissue; P = .01) in the imiquimod group. There was no recurrence of AGWs in patients with complete clearance at the 3-month follow-up and no serious adverse events. CONCLUSIONS AND RELEVANCE: Imiquimod, 5%, and the Mw vaccine were equally effective in achieving clinical and virologic clearance for HPV-6. A significant decline in the HPV-11 viral load was achieved only with the Mw vaccine. Efficacy and safety of intralesional Mw vaccine is comparable to that of imiquimod, 5%, in treatment of AGWs. TRIAL REGISTRATION: ctri.nic.in Identifier: CTRI/2009/091/000055.

Thermal management in hybrid InP/silicon photonic crystal nanobeam laser.

Thermal properties of InP-based quantum well photonic crystal nanobeam lasers heterogeneously integrated on silicon on insulator waveguides are studied. We show both numerically and experimentally the reduction of the thermal resistance of the III-V cavities by adjusting the composition of the layer which bonds the III-V materials to the silicon wafer and by adding an over-cladding on top of the cavities. Using a bonding layer made of benzocyclobutene and SiO(2) and an over-cladding of MgF(2), we found a decrease by a factor higher than 35 compared to air-suspended photonic crystal nanobeam cavities. Such optimized structures are demonstrated to operate under continuous wave pumping for several 10's of minutes despite the adverse effect of non-radiative surface recombination of carriers.

Experimental demonstration of a hybrid III-V-on-silicon microlaser based on resonant grating cavity mirrors.

We present the experimental demonstration of a novel class of hybrid III-V-on-silicon microlasers. We show that by coupling a silicon cavity to a III-V waveguide, the interaction between the propagating mode in the III-V waveguide and the cavity mode in the silicon resonator results in high, narrowband reflection back into the III-V waveguide, forming a so-called resonant mirror. By combining two such mirrors and providing optical gain in the III-V wire between these two mirrors, laser operation can be realized. This optically pumped device measures 55 by 2 µm, requires microwatt-level threshold pump power, and shows single-mode laser emission with a side-mode suppression ratio of up to 39 dB.

Health-related quality of life in Indian patients with three viral sexually transmitted infections: herpes simplex virus-2, genital human papilloma virus and HIV.

BACKGROUND: Health-related quality of life (HRQOL) has not been studied in Indian patients with viral sexually transmitted infections (STIs): herpes simplex virus-2 (HSV-2) and genital human papilloma virus (HPV) infections. Furthermore, there is no reported study that compares HRQOL among these two viral STIs and HIV. METHODS: All consenting adults with any of the three viral infections attending a sexually transmitted disease clinic and 35 healthy controls were enrolled. HRQOL was evaluated using the WHOQOL-BREF instrument, which evaluates QOL under physical, psychological, social and environmental domains. Data concerning demographic and socioeconomic status were collected. RESULTS: There were 65 (27.3%), 60 (25.2%) and 53 (22.3%) patients with HIV, HSV-2 and HPV, respectively, and 25 (10.5%) patients with mixed infections. The WHOQOL-BREF scores of patients in different STI groups were significantly lower than those of controls. The total HRQOL scores (mean±SD) were 280.1±83.56 (among controls), 196.9±72.41 (genital HPV), 141.0±50.50 (HSV-2), 101.0±75.25 (HIV) and 103.4±47.23(mixed infection groups). Mean HRQOL scores were lowest in the physical and psychological domains. HRQOL scores were least in HIV and mixed infections groups, while patients with genital HPV infection had significantly better HRQOL scores compared to other patient groups. Higher education and socioeconomic status had a positive influence on HRQOL. CONCLUSION: Viral STIs were associated with a significant reduction in HRQOL scores. Among patient groups, the greatest impact on HRQOL was seen in those with HIV and mixed infections and the least impact seen in those with genital HPV infection. Comprehensive care including counselling services need to be implemented in STI clinics.

Dynamics of band-edge photonic crystal lasers.

Band-edge photonic crystal lasers were fabricated and their temporal characteristics were minutely analyzed using a high resolution up-conversion system. The InGaAs/InP photonic crystal laser operates at room temperature at 1.55 microm with turn on time ranging from 17ps to 30ps.

High contrast reflection modulation near 1.55mum in InP 2D photonic crystals on silicon wafer.

We report on reflection modulation results near 1.55 mum in InP-based two-dimensional photonic crystals. The fabrication technology uses a polymeric bonding technique to integrate the InP thin-slab onto a Silicon wafer. Reflectivity modulation greater than 90% is obtained by pumping at 810 nm with optical excitation densities of 15 muJ/cm(2). The resulting optical broadband modulation is based on the saturation of absorption of InGaAs quantum wells at a photonic mode frequency tunable by lithography.