Device operation of organic tandem solar cells

A generalized methodology is developed to obtain the current-voltage characteristic of polymer tandem solar cells by knowing the electrical performance of both sub cells. We demonstrate that the electrical characteristics of polymer tandem solar cells are correctly predicted for both the series and parallel connection of the sub cells. The agreement with experiments allows us to investigate the effect of a reduced open-circuit voltage, short-circuit current or fill factor in one of the sub cells on the performance of the tandem cell. A low fill factor in one of the sub cells leads to a stronger reduction of the efficiency in a series configuration as compared to the parallel tandem device. (C) 2008 Elsevier B.V. All rights reserved

A REVIEW ARTICLE ON HERPES SIMPLEX ENCEPHALITIS

Abstract:Herpes Simplex encephalitis (HSE) is a life threatening outcome of Herpes simplex virus (HSV) infection of the central nervous system (CNS). HSVaccounts for 2-5 percent of all cases of encephalitis. One third of cases occur in those younger than 20 years old and one half in those older than 50 years old.Clinical diagnosis is recommended in the encephalopathic, febrile patients with focal neurological signs. However, the clinical findings are not pathogonomic because numerous other diseases of CNS can mimic HSE. Diagnosis should be confirmed based on medical history, analysis of cerebrospinal fluid (CSF) for protein and glucose contents, the cellular analysis and identifying the pathogens by serology and Polymerase Chain Reaction (PCR) amplification .The diagnostic gold standard is the detection of HSV DNA in the cerebrospinal fluid by PCR. But negative results need to be interpreted regarding thepatients clinical signs and symptoms and the time of CSF sampling. Spike and slow wave patterns is observed in Electroencephalogram (EEG).Neuroimaging, especially Magnetic Resonance Imaging (MRI) is essential for evaluating the patients, which shows temporal lobe edema or hemorrhage.All patients with HSE should be treated by intravenous Acyclovir (10mg/kg q8hr for 14-21 days). After completing therapy, PCR of the CSF can confirmthe elimination of replicating virus, assisting further management of the patient.Keywords:Herpes Simplex Virus (HSV), Encephalitis, Childre

National policies in ensuring access to quality and safety of drugs: A challenge or a prerequisite

Access to the essential medicines is an important challenge in the developing countries. To have access to the quality and affordable medicines, the pharmaceutical decision makers try different strategies. The production of generic and copy medicines is one of the strategies that if adopted based on the recognized standards and norms can be effective in raising the health status in the developing countries. However, the regulation enfeeblement has somewhat impaired the quality of generic and copy medicines and harmed the health life of consumers. Here we aim to reflect over the role of different beneficiaries including international organizations, governments, pharmaceutical companies, and NGOs in ensuring the feasible and sustainable access of citizens to the essential medicines. We also aim to highlight the importance of the patient status in the enhancement of the medical delivery

DFT explorations of quadrupole coupling constants for planar 5-fluorouracil pairs

Atomic scale properties of quadrupole coupling constants (CQ) have been evaluated for singular and paired 5-fluorouracil (FU) models. Structural possibilities and properties for various types of hydrogen bonded (HB) homo pairs of FU have been investigated based on density functional theory (DFT) calculations. The models have been optimized to obtain the minimum energy level structures and only the planar molecular pairs have been considered. Various types of HB interactions have also managed the molecular shapes for the FU pairs. Different types of energies and also electron transferring properties have been investigated by the evaluated optimized properties. The atomic scale results indicated different strengths of HB interactions for FU pairs according to the changes of CQ properties for atoms in the singular and paired systems depending on the strength of interactions. © 2016 Elsevier B.V

The Role of Serotonin in Fear Learning and Memory: A Systematic Review of Human Studies

Fear is characterized by distinct behavioral and physiological responses that are essential for the survival of the human species. Fear conditioning (FC) serves as a valuable model for studying the acquisition, extinction, and expression of fear. The serotonin (5-hydroxytryptamine, 5-HT) system is known to play a significant role in emotional and motivational aspects of human behavior, including fear learning and expression. Accumulating evidence from both animal and human studies suggests that brain regions involved in FC, such as the amygdala, hippocampus, and prefrontal cortex, possess a high density of 5-HT receptors, implicating the crucial involvement of serotonin in aversive learning. Additionally, studies exploring serotonin gene polymorphisms have indicated their potential influence on FC. Therefore, the objective of this work was to review the existing evidence linking 5-HT with fear learning and memory in humans. Through a comprehensive screening of the PubMed and Web of Science databases, 29 relevant studies were included in the final review. These studies investigated the relationship between serotonin and fear learning using drug manipulations or by studying 5-HT-related gene polymorphisms. The results suggest that elevated levels of 5-HT enhance aversive learning, indicating that the modulation of serotonin 5-HT2A receptors regulates the expression of fear responses in humans. Understanding the role of this neurochemical messenger in associative aversive learning can provide insights into psychiatric disorders such as anxiety and post-traumatic stress disorder (PTSD), among others

Oxygen isotope effect and phase separation in the optical conductivity of (La0.5_{0.5}Pr0.5_{0.5})0.7_{0.7}Ca0.3_{0.3}MnO3_3 thin films

The optical conductivities of films of (La$_{0.5}$Pr$_{0.5}$)$_{0.7}$Ca$_{0.3}$MnO$_3$ with different oxygen isotopes ($^{16}$O and $^{18}$O) have been determined in the spectral range from 0.3 to 4.3 eV using a combination of transmission in the mid-infrared and ellipsometry from the near-infrared to ultra-violet regions. We have found that the isotope exchange strongly affects the optical response in the ferromagnetic phase in a broad frequency range, in contrast to the almost isotope-independent optical conductivity above $T_C$. The substitution by $^{18}$O strongly suppresses the Drude response and a mid-infrared peak while enhancing the conductivity peak at 1.5 eV. A qualitative explanation can be given in terms of the phase separation present in these materials. Moreover, the optical response is similar to the one extracted from measurements in polished samples and other thin films, which signals to the importance of internal strain.Comment: 11 pages, 11 figures, to appear in PR

Numerical investigation on novel method for adhesively bonded t-joint between aluminum and sandwich panel

A common way to join dissimilar materials in industrial applications is to use adhesives. Marine industries use this kind of joints for attaching main hull to superstructure of the ships. Most previous researches have focused on composite-composite joints, while a few of them are devoted to aluminum- sandwich panel joints. This study focuses on the numerical static strength analysis of a typical aluminum-sandwich panel T-joints and improving its strength through a novel design. The results of numerical analyses are in a good agreement with those of the experimental tests and confirm the accuracy of numerical analyses. In analyzing the adhesive between joint elements, contact elements and cohesive zone model (CZM) in ANSYS as well as nonlinear analysis is used. Results show that change in joint geometry considered in this paper, caused a 7.25% increase in vertical failure load of the joint. This increase in strength of joint attained in a situation that because of the merging of the joined parts, the process of construction became easier

Relaxations of fluorouracil tautomers by decorations of fullerene-like SiCs: DFT studies

Decorations of silicon carbide (SiC) fullerene-like nanoparticles by fluorouracil (FU) and its tautomers are investigated through density functional theory (DFT) calculations. Two models of fullerene-like particles including Si12C8 and Si8C12 are constructed to be counterparts of decorated hybrid structures, FU@Si12C8 and FU@Si8C12, respectively. The initial models including original FU and tautomeric structures and SiC nanoparticles are individually optimized and then combined for further optimizations in the hybrid forms. Covalent bonds are observed for FU@Si12C8 hybrids, whereas non-covalent interactions are seen for FU@Si8C12 ones. The obtained properties indicated that Si12C8 model could be considered as a better counterpart for interactions with FU structures than Si8C12 model. The results also showed significant effects of interactions on the properties of atoms close to the interacting regions in nanoparticles. Finally, the tautomeric structures show different behaviors in interactions with SiC nanoparticles, in which the SiC nanoparticles could be employed to detect the situations of tautomeric processes for FU structures. © 2016 Elsevier B.V