Computational Design of Crescent Shaped Promising Nonfullerene Acceptors with 1,4-Dihydro-2,3-quinoxalinedione Core and Different Electron-withdrawing Terminal Units for Photovoltaic Applications.

This study aims to design a series of nonfullerene acceptors (NFAs) for photovoltaic applications having 1,4-dihydro-2,3-quinoxalinedione fused thiophene derivative as the core unit and 1,1-dicyanomethylene-3-indanone (IC) derivatives and different π-conjugated molecules other than IC as terminal acceptor units. All the investigated NFAs are found air-stable as the computed highest occupied molecular orbitals (HOMOs) are below the air oxidation threshold (ca. -5.27 eV vs saturated calomel electrode). The studied NFAs can act as potential nonfullerene acceptor candidates as they are found to have sufficient open-circuit voltage (Voc) and fill factor (FF) ranging from 0.62 to 1.41 V and 83%-91%, respectively. From the anisotropic mobility analysis, it is noticed that the studied NFAs except dicyano-rhodanine terminal unit containing NFA, exhibit better electron mobility than the hole mobility, and therefore, they can be more promising electron transporting acceptor materials in the active layer of an organic photovoltaic cell. From the optical absorption analysis, it is noted that all the designed NFAs have the maximum absorption spectra ranging from 597 nm-730 nm, which lies in the visible region and near-infrared (IR) region of the solar spectrum. The computed light-harvesting efficiencies for the PM6 (thiophene derivative donor selected in our study):NFA blends are found to lie in the range of 0.96-0.99, which indicates efficient light-harvesting by the PM6:NFA blends during photovoltaic device operation.

Enhancement of air-stability, π-stacking ability, and charge transport properties of fluoroalkyl side chain engineered n-type naphthalene tetracarboxylic diimide compounds.

In this study, the impact of fluoroalkyl side chain substitution on the air-stability, π-stacking ability, and charge transport properties of the versatile acceptor moiety naphthalene tetracarboxylic diimide (NDI) has been explored. A density functional theory (DFT) study has been carried out for a series of 24 compounds having different side chains (alkyl, fluoroalkyl) through the imide nitrogen position of NDI moiety. The fluoroalkyl side chain engineered NDI compounds have much deeper highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) than those of their alkyl substituted compounds due to the electron withdrawing nature of fluoroalkyl groups. The higher electron affinity (EA > 2.8 eV) and low-lying LUMO levels (<-4.00 eV) for fluoroalkyl substituted NDIs reveal that they may exhibit better air-stability with superior n-type character. The computed optical absorption spectra (∼386 nm) for all the investigated NDIs using time-dependent DFT (TD-DFT) lie in the ultra-violet (UV) region of the solar spectrum. In addition, the low value of the LOLIPOP (Localized Orbital Locator Integrated Pi Over Plane) index for fluoroalkyl side chain comprising NDI compounds indicates better π-π stacking ability. This is also in good agreement for the predicted π-π stacking interaction obtained from a molecular electrostatic potential energy surface (ESP) study. The π-π stacking is thought to be of cofacial interaction for the fluoroalkyl substituted compounds and herringbone interaction for the alkyl substituted compounds. The calculated results shed light on why side chain engineering with fluoroalkyl groups can effectively lead to better air-stability, π-stacking ability and improved charge transport properties.

Childhood sexual abuse in adult patients with borderline personality disorder.

BACKGROUND: Researchers have found elevated rates of childhood sexual abuse (CSA) in borderline personality disorder (BPD) patients. They have also implicated the role of CSA later in BPD. However, there has been a scarcity of studies regarding this in Indian population. OBJECTIVES: To profile the occurrence of CSA and its parameters in BPD patients and to document symptomatology of BPD associated with CSA. MATERIALS AND METHODS: Thirty-six consecutive patients with BPD were administered with a two-staged semi-structured interview by different interviewers with the first stage for collecting sociodemographic details and confirming BPD diagnosis and the second stage for collecting information about CSA. RESULTS: Of 36 BPD patients, 16 (44.44%) reported a history of definite CSA. The majority of CSA associated with BPD were having characteristics of onset at 7-12 years, <10 occasions of abuse, perpetrator being a close relative or a close acquaintance and genital type of CSA. Identity disturbances (P = 0.0354), recurrent suicidal/self-harm behavior (P = 0.0177), and stress-related paranoid/dissociative symptoms (P = 0.0177) were significantly associated with the presence of CSA while unstable interpersonal relationships (P = 0.001) were significantly associated with the absence of CSA. CONCLUSION: Significant proportion of BPD patients reported CSA. The specific symptom profile of BPD patients can be used to predict the presence of CSA in these patients, which has a direct implication in the treatment of these patients.

HIV-associated dementia: A diagnostic dilemma.

BACKGROUND: Considerable clinical research has been conducted to increase our knowledge in understanding the underlying neuropathological significance of HIV viral infection. AIM: To find the incidence of HIV Associated Dementia in a suburban part of India. MATERIALS AND METHODS: 6135 prospective cases from January 2008 to August 2010 were subjected to pretest counseling. Those willing were tested for HIV status using western blot test. RESULTS: 5688 (92.71%) underwent for detection of HIV.273 (4.8%) were tested positive. 246 out of these (90.10%) were put on ART. 1 (0.37%) was detected to have HAD stage II.38 cases (18.92%) had varied psychiatric symptoms. CONCLUSION: HAART has considerably reduced morbidity in HIV infection.