Exciton generation and dissociation mechanisms in organic bulk heterojunction solar cell materials.

Characterization of the optical and electrical properties of organic solar cell materials is of prime importance to organic solar cell design. This thesis describes the use of capacitive photocurrent measurements to study the exciton generation and dissociation mechanisms of organic solar cell materials. The emphasis is on the study of the methanofullerene derivatives (e.g., PCBM) which act as the electron acceptor material. This is because much work has already been done studying electron donating polymers used in organic solar cells (in an effort to enhance their absorbance coefficient), but less information is available on the acceptor material. In the blend films of MDMO-PPV: PCBM, the charge generation rate in PCBM was discovered to be much higher than would be expected from the absorbance cross-section. This observation led to design of a photovoltage bleaching experiment to examine the charge generation mechanism. Here the effect of illumination by a tunable light source on the open circuit photovoltage of a MDMO-PPV: PCBM bulk heterojunction solar cell was measured. Illumination of light at the PCBM ground state singlet exciton causes a sharp decrease in the photovoltage, while illumination at the ground state MDMO-PPV exciton shows no change. A direct pathway of recombination of above gap generated charge carriers was identified. Photovoltage bleaching results suggests that excitation at the PCBM ground singlet state exciton increases the recombination rate of higher energy excitations, either by acting as a recombination center or by forcing higher energy carriers into short lived states that recombine before reaching the contacts. The fact that the photovoltage bleaching correlates with the ground state PCBM singlet exciton suggests that charge dissociation from PCBM preferentially generates long-lived localized states. Capacitive photocurrent measurements were then performed on isolated methanofullerene derivatives, with the polymer donor material absent. Several low energy transitions were resolved in the optical spectroscopy of methanofullerene derivatives. These low energy states lay below the optical energy band-gap of these materials, so that their presence was unexpected. It was determined that the low energy states overlapped with the plasmon state of the highly conducting substrates (Indium Tin Oxide) which were in close proximity with the PCBM. Plasmon states in ITO have been observed previously, but the results presented in this thesis are unique in that this is the first evidence of charge transfer from the plasmon state of ITO to a high electron affinity fullerene derivative. The results show the evidence of charge transfer from PCBM to ITO over a broad wavelength range of 400 - 2400 nm (3 eV - 0.5 eV). Few materials have been observed to have absorbance and charge transfer over such a large range of energies in the infra-red regime. These results open a new direction for development of organic solar cell design with higher power conversion efficiencies

Dispersion of narrow diameter carbon nanotubes for optical characterization.

Optical properties of carbon nanotubes have recently attracted considerable amount of attention. Due to there direct band gap material characteristic these and dimension of the order of nano meters they find potential applications in the field of nano photonics. Thus the optical study of carbon nanotubes is important for both fundamental research and for the next generation technical applications. In this thesis single walled carbon nanotubes were dispersed in various encapsulates such as surfactants, polymers, proteins etc to separate them individually and study there optical properties. The individually dispersed single walled carbon nanotubes displayed unique absorbance spectra. The optical absorption spectrum of a particular tube is expected to be dominated by a series of relatively sharp inter-band transitions, at energies associated with the van Hove singularities, the absorbance spectrum obtained on our samples were consistent with this expectation. Our samples also showed sharp photoluminescence peaks mostly from the semiconducting single walled carbon nanotubes. The detailed overlap of the absorbance spectra and photoluminescence spectra lead us to believe that our samples contain mainly individual tubes encapsulated in one of the surfactants or polymers. Thin film transistors (TFT) were made with a mesh of single walled carbon nanotubes as the active channel on top of a silicon/silicon oxide substrate, with silicon acting as a back gate and titanium/gold electrodes were evaporated on top of the nanotube film. Photocurrent properties of these thin films were investigated and they showed a huge change in the photocurrent in the presence and absence of the laser light. Thin films of carbon nanotubes were also deposited on rectangular silicon substrates and the influence of applied strain in the presence of laser light was investigated. These films showed a huge change in resistance on application of mechanical strain. Raman measurements were also performed on these thin films and the obtained radial breathing mode (RBM) data helped resolve the diameter of many single walled carbon nanotubes

The relationship between emotional intelligence and academic achievement in medical undergraduate

Background: In today’s era of technology, intelligence and success are not viewed the same way they were before. New theories of intelligence have been introduced and are gradually replacing the traditional theory. Academic achievement is based on creativity, emotions, and interpersonal skills. Methods: The aim of this study was to see whether there is a relationship between emotional intelligence and academic success. Study was done on 1st MBBS students of Govt. Medical College, Bhavnagar. The sample size was 75 students (boys and girls). The emotional intelligence questionnaire from Institute for Health and Human Potential was given to the students, Depending on the EQ score we divided the students in to five groups and compared with their academic performance. Results: Study showed inverse relationship between emotional intelligence and academic achievement.Conclusion: There is a negative relation among emotional intelligence and academic achievement of the participants

ROLE OF VENTILATION IN CASES OF ACUTE RESPIRATORY DISTRESS SYNDROME /ACUTE LUNG INJURY

Introduction: Acute lung injury (ALI) and Acute Respiratory Distress Syndrome (ARDS) are characterized by re- fractory hypoxemia that develops secondary to high-permeability pulmonary edema. These syndromes are gaining more attention as a means of better comprehending the pathophysiology of ARDS and possiblyfor modifying venti- latory management. In this context a study was done to compare role of invasive and non-invasive ventilation in cases of ARDS/ALI. Methods: in this study patients of ARDS admitted in intensive care ward due to Pulmonary and Extra Pulmonary Sepsis (Lung Injury) during May 2008 to April 2011were included in the study. All the patients were clinically ex- amined and investigated after taking informed consent. Traumatic patients with ARDS were excluded from study. Results: In this study of 100 cases of ARDS/ALI admitted in ICU, all 44 cases on non‐invasive ventilation were improved. Whereas, out of 44 cases on invasive ventilation only 5 improved and 39 were expired. Rest 12 required no ventilator support. Conclusion: Early application of Non-invasive ventilation in patients of ARDS/ALI, in form of high PEEP and low Tidal Volume, which helps in clearance of secretion and prevents collapse of alveoli and thereby decreases need of invasive ventilation as well as decreases the mortality due to ARDS/ALI;and thereby 100% chances of improve- ment. In invasive ventilation, outcome of the patients is not favorable.

Endoscopic Retrograde Cholangiopancreatography-Related Early Perforations: A Study of Effects of Procedure Duration, Complexity, and Endoscopist Experience

BACKGROUND: Perforations (Perf) during endoscopic retrograde cholangiopancreatography (ERCP) are rare (\u3c 1%) but potentially fatal events (up to 20% mortality). Given its rarity, most data is through case series studies from centers or analysis of large databases. Although a meta-analysis has shown fewer adverse events as a composite (bleeding, pancreatitis, Perf) during ERCP performed at high-volume centers, there is very little real-world data on endoscopist and center procedural volumes, ERCP duration and complexity on the occurrence of Perf. AIM: To study the profile of Perf related to ERCP by center and endoscopist procedure volume, ERCP time, and complexity from a national endoscopic repository. METHODS: Patients from clinical outcomes research initiative-national endoscopic database (2000-2012) who underwent ERCP were stratified based on the endoscopist and center volume (quartiles), and total procedure duration and complexity grade of the ERCP based on procedure details. The effects of these variables on the Perf that occurred were studied. Continuous variables were compared between Perf and no perforations (NoPerf) using the Mann-Whitney U test as the data demonstrated significant skewness and kurtosis. RESULTS: A total of 14153 ERCPs were performed by 258 endoscopists, with 20 reported Perf (0.14%) among 16 endoscopists. Mean patient age in years 61.6 ± 14.8 CONCLUSION: Overall adverse events as a composite during ERCP are known to occur at a lower rate with higher volume endoscopists and centers. However, Perf studied from the national database show prolonged and more complex procedures performed by high-volume endoscopists at high-volume centers contribute to Perf

Sonographically Guided Lumbar Puncture in Pediatric Patients

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135581/1/jum201332122191.pd

Outcomes of Medicare-age eligible NHL patients receiving RIC allogeneic transplantation: a CIBMTR analysis

The application of allogeneic hematopoietic cell transplantation (allo-HCT) in non-Hodgkin lymphoma (NHL) patients ≥65 years in the United States is limited by lack of Medicare coverage for this indication. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we report allo-HCT outcomes of NHL patients aged ≥65 years (older cohort; n = 446) compared with a cohort of younger NHL patients aged 55-64 years (n = 1183). We identified 1629 NHL patients undergoing a first reduced-intensity conditioning (RIC) or nonmyeloablative conditioning allo-HCT from 2008 to 2015 in the United States. Cord blood or haploidentical transplants were excluded. The median age was 68 years (range 65-77) for the older cohort vs 60 years (range 55-64) in the younger cohort. The 4-year adjusted probabilities of nonrelapse mortality (NRM), relapse/progression (R/P), progression-free survival (PFS), and overall survival (OS) of the younger and older groups were 24% vs 30% (P = .03), 41% vs 42% (P = .82), 37% vs 31% (P = .03), and 51% vs 46% (P = .07), respectively. Using multivariate analysis, compared with the younger group, the older cohort was associated with increased NRM, but there was no difference between the 2 cohorts in terms of R/P, PFS, or OS. The most common cause of death was disease relapse in both groups. In NHL patients eligible for allo-HCT, there was no difference in OS between the 2 cohorts. Age alone should not determine allo-HCT eligibility in NHL, and Medicare should expand allo-HCT coverage to older adults

Cladribine plus cytarabine plus venetoclax in acute myeloid leukemia relapsed or refractory to venetoclax plus hypomethylating agent

Not available

Competence in Endoscopic Ultrasound and Endoscopic Retrograde Cholangiopancreatography, From Training Through Independent Practice.

BACKGROUND & AIMS: It is unclear whether participation in competency-based fellowship programs for endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) results in high-quality care in independent practice. We measured quality indicator (QI) adherence during the first year of independent practice among physicians who completed endoscopic training with a systematic assessment of competence. METHODS: We performed a prospective multicenter cohort study of invited participants from 62 training programs. In phase 1, 24 advanced endoscopy trainees (AETs), from 20 programs, were assessed using a validated competence assessment tool. We used a comprehensive data collection and reporting system to create learning curves using cumulative sum analysis that were shared with AETs and trainers quarterly. In phase 2, participating AETs entered data into a database pertaining to every EUS and ERCP examination during their first year of independent practice, anchored by key QIs. RESULTS: By the end of training, most AETs had achieved overall technical competence (EUS 91.7%, ERCP 73.9%) and cognitive competence (EUS 91.7%, ERCP 94.1%). In phase 2 of the study, 22 AETs (91.6%) participated and completed a median of 136 EUS examinations per AET and 116 ERCP examinations per AET. Most AETs met the performance thresholds for QIs in EUS (including 94.4% diagnostic rate of adequate samples and 83.8% diagnostic yield of malignancy in pancreatic masses) and ERCP (94.9% overall cannulation rate). CONCLUSIONS: In this prospective multicenter study, we found that although competence cannot be confirmed for all AETs at the end of training, most meet QI thresholds for EUS and ERCP at the end of their first year of independent practice. This finding affirms the effectiveness of training programs. Clinicaltrials.gov ID NCT02509416

Competence in Endoscopic Ultrasound and Endoscopic Retrograde Cholangiopancreatography, From Training Through Independent Practice.

BACKGROUND & AIMS: It is unclear whether participation in competency-based fellowship programs for endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) results in high-quality care in independent practice. We measured quality indicator (QI) adherence during the first year of independent practice among physicians who completed endoscopic training with a systematic assessment of competence. METHODS: We performed a prospective multicenter cohort study of invited participants from 62 training programs. In phase 1, 24 advanced endoscopy trainees (AETs), from 20 programs, were assessed using a validated competence assessment tool. We used a comprehensive data collection and reporting system to create learning curves using cumulative sum analysis that were shared with AETs and trainers quarterly. In phase 2, participating AETs entered data into a database pertaining to every EUS and ERCP examination during their first year of independent practice, anchored by key QIs. RESULTS: By the end of training, most AETs had achieved overall technical competence (EUS 91.7%, ERCP 73.9%) and cognitive competence (EUS 91.7%, ERCP 94.1%). In phase 2 of the study, 22 AETs (91.6%) participated and completed a median of 136 EUS examinations per AET and 116 ERCP examinations per AET. Most AETs met the performance thresholds for QIs in EUS (including 94.4% diagnostic rate of adequate samples and 83.8% diagnostic yield of malignancy in pancreatic masses) and ERCP (94.9% overall cannulation rate). CONCLUSIONS: In this prospective multicenter study, we found that although competence cannot be confirmed for all AETs at the end of training, most meet QI thresholds for EUS and ERCP at the end of their first year of independent practice. This finding affirms the effectiveness of training programs. Clinicaltrials.gov ID NCT02509416