Level of polychlorinated biphenyls in tumor and blood serum of breast cancer patients and control subjects from Punjab, Pakistan

The current study examined the level of Polychlorinated biphenyls (PCBs) in tumor and blood serum of female breast cancer patients and control individuals recruited from Punjab, Pakistan. Breast tumor and blood serum from 40 patients and only blood serum from ten control subjects were obtained and concentration of 32 PCB congeners was analyzed through Gas chromatography coupled with Mass spectrophotometry. Sociodemographic variables of the patients along with essential clinical and haematological parameters were taken as covariates. Tumor reflects the highest median (min-max) concentration (ng g-1 lw) of ƩPCBs at 115.94 (0.05-17.75) followed by 16.53 (0.09-2.94) and 5.24 (0.01-0.59) in blood serum of cancer patients and control group respectively. Median concentrations (ng g-1 lw) of non-dioxine like ƩPCBs were considerably higher at 83.04, 32.89 and 4.27 compared to 13.03 and 3.50 and 0.97 for dioxin like ƩPCBs in tumor, serum of breast cancer patients and control subjects respectively. PCB-87 was most dominant congeners in tumor followed by PCB-170 and -82 whereas PCB-28 and -52 reflected greatest contribution in serum of breast cancer patients. Blood haemoglobin, potassium and chloride ions showed significant positive whereas body mass index reflect inverse relationship when regressed with ƩPCBs in tumor. This pioneer study depicts elevated concentrations of PCBs in patients compared to control, reflecting potential positive association of PCBs with breast cancer which need further confirmation. We concluded that chronic exposure to PCBs might be associated with an increasing number of breast cancer incidences in developing countries like Pakistan, which should be further elucidated through detail in vitro and in vivo studies.

Fabricating a 3D floating porous PDMS - Ag/AgBr decorated g-C3N4 nanocomposite sponge as a re-usable visible light photocatalyst

In this study, polymeric graphitic carbon nitride (g-C3N4) semiconductors was synthesized via a thermal condensation method. Subsequently, Ag/AgBr nanoparticles with varying ratios were decorated onto the g-C3N4 surface using the water/oil emulsion method. The resulting nanocomposites were characterized using XRD for phase identification and structural analysis, HR-TEM and SEM&EDAX for morphological structure, particle size, and elemental composition analysis, and XPS for investigating the chemical state and electronic structure. The impact of Ag/AgBr content on the optical properties of g-C3N4 were also studied such as (optical bandgap (Eg), refractive index (n), extinction coefficient (k), optical conductivity (σopt) and dielectric function (ε*)), Electrochemical impedance spectroscopy (EIS), PL spectroscopy and Chrono-amperometric investigations were conducted to assess the charge transfer capabilities and long-term durability of the prepared nanocomposites. The results revealed a reduction in Ag/AgBr particle size with an increase in g-C3N4 content, accompanied by a decrease in the optical bandgap from 2.444 eV to 2.393 eV. Furthermore, the nanocomposites exhibited enhanced degradation efficiencies of RhB dye, with the highest tested content of Ag/AgBr achieving 100% degradation after 120 min of irradiation. However, the challenge of catalyst separation after the degradation process remained. To address this issue, we developed a novel approach by impregnating Ag/AgBr@g-C3N4 photocatalyst onto a floating porous sponge using a simple sugar-template technique, offering potential as a reusable photocatalyst material. Furthermore, the 3D PDMS - Ag/AgBr@g-C3N4 photocatalyst was evaluated and found to maintain nearly the same photocatalytic efficiency for up to 5 consecutive cycles.

Growth, hemato-biochemical, immune-antioxidant response, and gene expression in Nile tilapia (Oreochromis niloticus) received nano iron oxide-incorporated diets

Nanotechnology has recently played a key role in tackling many aquacultures issues. Hence, the present study targets the evaluation of dietary inclusion of nano iron oxide (nFe₂O₃) on growth performance, hematology, immune-antioxidant responses, ionic regulation and expression of related genes in Nile tilapia (Oreochromis niloticus). Fish were fed supplementary nFe₂O₃ at rates of zero (control), 0.5, and 1 g/kg diet for 30 days. Obtained data demonstrated that nFe₂O₃ significantly (P < 0.05) augmented growth performance (final weight and length, body mass gain, specific growth rate, feed conversion ratio, and length gain rate). Hematological picture {RBCs, Hb, MCV, MCH and MCHC, and leukocytes interpretations (WBCs and monocytes)}; and biochemical indexes including (AST and ALT; total protein; and glucose, and cortisol) were significantly (P < 0.05) improved in nFe₂O₃ supplemented groups. Plasma ionic concentration was also altered with nFe₂O₃ supplementation, and 1g nFe₂O₃ revealed the most marked increase in plasma (Na⁺) potassium (K⁺) levels. Similarly, IgM, nitrous oxide (NO), and lysozyme activity, plus superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities showed a remarkable improvement in 1g nFe₂O₃ group compared to the control. Expression of Insulin-Like Growth Factor-1 (IGF-1) and interleukin 1-β (IL-1β) genes were significantly up-regulated in nFe₂O₃ supplemented groups. Briefly, dietary nFe₂O₃ inclusion had enhanced properties on growth; hemato-biochemical; immune, antioxidative profiles; and related genes expression of O. niloticus, with a recommended concentration of 1g nFe₂O₃.

Feasibility of a Generative Adversarial Network for Artifact Removal in Experimental Photoacoustic Imaging

Photoacoustic tomography (PAT) reconstruction is an expeditiously growing interest among biomedical researchers because of its possible transition from laboratory to clinical pre-eminence. Nonetheless, the PAT inverse problem is yet to achieve an optimal solution in rapid and precise reconstruction under practical constraints. Precisely, the sparse sampling problem and random noise are the main impediments to attaining accuracy but in support of rapid PAT reconstruction. The limitations are associated with acquiring undersampled artifacts that deteriorate the optimality of the reconstruction task. Therefore, the former achievements of fast image formation limit the modality for clinical settings. Delving into the problem, here we explore a deep learning-based generative adversarial network (GAN) to improve the image quality by denoising and removing these artifacts. The specially designed attributes and unique manner of optimizing the problem, such as incorporating the data set limitations and providing stable training performance, constitute the main motivation behind the employment of GAN. Moreover, exploitation of the U-net variant as a generator network offers robust performance in terms of quality and computational cost, which is further validated with the detailed quantitative and qualitative analysis. The quantitatively evaluated structured similarity indexing method = 0.980 ± 0.043 and peak signal-to-noise ratio = 31 ± 0.002 dB state that the proposed solution provides the high-resolution image at the output, even training with a low-quality data set.

Prescribing Patterns for Upper Respiratory Tract Infections: A Prescription-Review of Primary Care Practice in Quetta, Pakistan and the Implications

Background: To identify and address the potential overuse of antibiotics, it is important to ascertain the prescribing practices of physicians. We, therefore, conducted this prescription analysis to document URTI-specific antibiotic prescription frequency in a public primary healthcare setting of Quetta city, Pakistan.

Methods: A retrospective record review was conducted of all prescriptions for URTIs in Combined Military Hospital, Quetta from 1 March to 31st May 2021. The Mann-Whitney U and Jonckheere–Terpstra test was used to evaluate the association between the tendencies of a different group of prescribers. p-value of <0.05 was of statistical significance.

Results: Over the 3 months, 50,705 prescriptions were screened and analyzed according to the established inclusion and exclusion criteria. A total of 4,126 (8.13%) URTI prescriptions met the inclusion criteria, of which 2,880 (69.80%) prescriptions contained antibiotics. Among all antibiotics, penicillins (Amoxicillin + Clavulanate) were the most prescribed antibiotic, constituting 1,323 (45.9%) of total antibiotics prescribed for all cases, followed by the Macrolide group 527 (18.2%). The Jonckheere–Terpstra test revealed a statistically significant association between the status of the prescriber and the diagnosis (p = 0.002). Furthermore, a moderate positive trend was reported with specialists being more competent in antibiotic prescribing based on their diagnosis, followed by postgraduates and house officers (τ = 0.322).

Conclusion: The prescribing patterns for the management of URTIs in the hospital were inconsistent with current guidelines. Strict adherence to guidelines must be ensured and antibiotic prescribing for URTIs should be discouraged.

Evaluation of serum procalcitonin level as a biomarker for disease severity in COVID-19 patients

The pandemic of coronavirus disease 2019 (COVID-19) has infected millions of individuals around the globe. Forecasting the COVID-19 severity is essential, and various biomarkers could be used to evaluate it. The current study was therefore aimed to evaluate the serum pro-calcitonin (PCT) level as a biomarker for bacterial co-infection and disease severity in COVID-19 patients. A total of 430 COVID-19 positive individuals were examined, in which 332 (77.2%) were male individuals while 98 (22.8%) were female individuals. Among the examined samples, 281 were classified as moderate (PCT value 0.07 ± 0.06 ng/mL), 95 were severe (PCT value 0.5 ± 0.4 ng/mL), and 54 were classified as critical (PCT value > 1 ng/mL) individuals. The increase in the total serum level of PCT was observed with the severity of the disease (p < 0.05). The statistical analysis represented no association of PCT value with gender (p 0.9650) while revealed a significant association (p < 0.001) with the age and PCT value in COVID-19 patients. It can be concluded that the serial PCT measurement could determine the prognosis of the disease and the presence of bacterial co-infection in COVID-19 patients. Further exploration of the topic is needed to evaluate the effect of different therapies on the PCT level and to prescribe specific treatment options for coinfection.

To Push or To Pull? In a Post-COVID World, Supporting and Incentivizing Antimicrobial Drug Development Must Become a Governmental Priority

The COVID-19 pandemic has refocused attention worldwide on the dangers of infectious diseases, in terms of both global health and the effects on the world economy. Even in high income countries, health systems have been found wanting in dealing with the new infectious agent. However, the even greater long-term danger of antimicrobial resistance in pathogenic bacteria and fungi is still under-appreciated, especially among the general public. Although antimicrobial drug development faces significant scientific challenges, the gravest challenge at the moment appears to be economic, where the lack of a viable market has led to a collapse in drug development pipelines. There is therefore a critical need for governments across the world to further incentivize the development of antimicrobials. Most incentive strategies over the past decade have focused on so-called "push" incentives that bridge the costs of antimicrobial research and development, but these have been insufficient for reviving the pipeline. In this Perspective, we analyze the current incentive strategies in place for antimicrobial drug development, and focus on "pull" incentives, which instead aim to improve revenue generation and thereby resolve the antimicrobial market failure challenge. We further analyze these incentives in a broader "One Health" context and stress the importance of developing and enforcing strict protocols to ensure appropriate manufacturing practices and responsible use. Our analysis reiterates the importance of international cooperation, coordination across antimicrobial research, and sustained funding in tackling this significant global challenge. A failure to invest wisely and continuously to incentivize antimicrobial pipelines will have catastrophic consequences for global health and wellbeing in the years to come.

BONE DEVELOPMENT AND FRACTURE HEALING IS NORMAL IN MICE THAT HAVE A DEFECT IN THE DEVELOPMENT OF THE LYMPHATIC SYSTEM

Ectopic lymphatics form in bone and promote bone destruction in diseases such as Gorham-Stout disease, generalized lymphatic anomaly, and kaposiform lymphangiomatosis. However, the role lymphatics serve in normal bone development and repair is poorly understood. The objective of this study was to characterize bone development and fracture healing in mice that have a defect in the development of the lymphatic vasculature. We found that bones in wild-type adult mice and mouse embryos did not have lymphatics. We also found that bone development was normal in Vegfr3Chy/Chy embryos. These mice do not have lymphatics and die shortly after birth. To determine whether lymphatics serve a role in postnatal bone development and fracture healing, we analyzed bones from Vegfr3wt/Chy mice. These mice are viable and have fewer lymphatics than wild-type mice. We found that postnatal bone development and fracture healing was normal in Vegfr3wt/Chy mice. Taken together, our results suggest that lymphatics do not play a major role in normal bone development or repair.

A Deep Learning Approach for the Photoacoustic Tomography Recovery From Undersampled Measurements

Photoacoustic tomography (PAT) is a propitious imaging modality, which is helpful for biomedical study. However, fast PAT imaging and denoising is an exigent task in medical research. To address the problem, recently, methods based on compressed sensing (CS) have been proposed, which accede the low computational cost and high resolution for implementing PAT. Nevertheless, the imaging results of the sparsity-based methods strictly rely on sparsity and incoherence conditions. Furthermore, it is onerous to ensure that the experimentally acquired photoacoustic data meets CS's prerequisite conditions. In this work, a deep learning-based PAT (Deep-PAT)method is instigated to overcome these limitations. By using a neural network, Deep-PAT is not only able to reconstruct PAT from a fewer number of measurements without considering the prerequisite conditions of CS, but also can eliminate undersampled artifacts effectively. The experimental results demonstrate that Deep-PAT is proficient at recovering high-quality photoacoustic images using just 5% of the original measurement data. Besides this, compared with the sparsity-based method, it can be seen through statistical analysis that the quality is significantly improved by 30% (approximately), having average SSIM = 0.974 and PSNR = 29.88 dB with standard deviation ±0.007 and ±0.089, respectively, by the proposed Deep-PAT method. Also, a comparsion of multiple neural networks provides insights into choosing the best one for further study and practical implementation.

QoS Based Optimal Resource Allocation and Workload Balancing for Fog Enabled IoT

This paper is aimed at efficiently distributing workload between the Fog Layer and the Cloud Network and then optimizing resource allocation in cloud networks to ensure better utilization and quick response time of the resources available to the end user. We have employed a Dead-line aware scheme to migrate the data between cloud and Fog networks based on data profiling and then used K-Means clustering and Service-request prediction model to allocate the resources efficiently to all requests. To substantiate our model, we have used iFogSim, which is an extension of the CloudSim simulator. The results clearly show that when an optimized network is used the Quality of Service parameters exhibit better efficiency and output.

15 Structured Geriatric Liaison Services in Mental Health Inpatient Facilities

Introduction

Older people admitted to mental health facilities may be at increased risk of deterioration in the physical co-morbidities and increased rates of mortality when admitted in acute medical settings. Our model of care focuses on intervening in the physical aspect of patients admitted in the mental health unit addressing their comorbidities and polypharmacy and offering staff support during the admission process. Our Older Mental Health Unit is based in the district hospital with a total of 22 beds for people over 65 years old distributed in two areas: dementia with behavioral and psychological symptoms (BPS) and functional disorders.

Methods

Allocated geriatrician once a week to attend MDT and medical ward rounds. 5 working days telephone consultations for advice and supporting trainees in teaching and research. We measure the impact of our intervention comparing the data predating our intervention comparing 20 patients in each period 2016 and 2018.

Results

Mean age increased from 74.3 to 77.8 in a two year period with an average of 3.5 medical co-morbidities. Reduction in polypharmacy from 7.15 to 5.5 number of medication, 58% reduction in the number of hospital transfers and 90% reduction in specialty referrals.

Conclusions

Structured Geriatric Liaison Services in Mental Health in inpatient facilities are shown to be effective in reducing acute hospital and outpatient clinic attendances minimising the challenges of management of these patients in non-mental health facilities.

Knowledge and practice of adolescent females about menstruation and menstruation hygiene visiting a public healthcare institute of Quetta, Pakistan

BACKGROUND

The current study is aimed to assess menstruation-related knowledge and practices of adolescent females visiting a public health care institute of Quetta city, Pakistan.

METHODS

A questionnaire-based cross-sectional survey was conducted. Nine hundred and twenty three female adolescents attending general out-patient departments of Mohtarma Shaheed Benazir Bhutto Hospital Quetta, Balochistan, was approached for data collection. Based on the objectives of the study, descriptive analysis was conducted and SPSS v. 21.0 was used for the data analysis.

RESULTS

Demographic characteristics revealed that the mean age of the respondents was 15 years. Mothers' (67%) were the main source of menstruation-related information. Majority (77.7%) of our respondents never had a class or session regarding menstruation-related education in their schools. About (44%) knew that menstruation is a physiological phenomenon while 60.2% knew that menstrual blood comes from the vagina. Nearly 40% of our study respondents missed their schools because of menarche. The use of absorbent material was frequent (90%) among the adolescent females and (68.7%) used commercially available sanitary napkins/pads. Although majority of the respondents (58.2%) were not taking baths during menstruation, 80.5% do cleaned their genitalia with water during menstruation.

CONCLUSION

Female adolescents of our study had certain misconception regarding menstruation because of poor access to health-related education. Education can be provided at healthcare facilities, residential area as well as religious centers. Adolescent reproductive health should be included in the school curriculum; this will influence general reproductive health of females.

Application of leaching tests on phosphogypsum by infiltration-percolation

The phosphoric acid production obtained by attacking phosphate rock by sulphuric acid cogenerates considerable quantities of phosphogypsum. The world cogeneration is estimated about 100-280 Mt per year. In another context of sustainable development, the phosphate chemical industry develops different ways of phosphogypsum valorization, which makes its storage stack in a suitable way for its potential use as an industrial by-product. Although, this storage can cause an environmental impact largely due to the transfer of trace elements (TEs) to groundwater by leaching. It is therefore important to evaluate the impact linked to the storage in order to limit this transfer. The evaluation is usually performed through leaching tests in columns or reactor. In this work, leaching tests were performed in columns by infiltration-percolation on two filter mediums: phosphogypsum and synthetic sandy soils. The results showed that the phosphogypsum is acting as a filter, which retains and releases the TEs. Most of these TEs (Pb, Se, Ag, Zn and Cu) were highly retained in the synthetic soils surfaces and their contents in waters were considerably lower than the maximum contaminant levels (MCLs). Although As, Cd, Cr and Ni were strongly transferred to groundwater, their respective contents were higher than the MCLs.

Frequency and predictors of anxiety and depression among pregnant women attending tertiary healthcare institutes of Quetta City, Pakistan

Background

Anxiety and depression (A&D) are commonly reported among pregnant women from all over the world; however, there is a paucity of workable data from the developing countries including Pakistan. The current study, therefore, aims to find out the frequency and predictors of A&D among pregnant women attending a tertiary healthcare institutes in the city of Quetta, in the Balochistan province, Pakistan.

Methods

A questionnaire based, cross-sectional survey was conducted. The pre-validated Hospital Anxiety and Depression Scale (HADS) were used to assess the frequency of A&D among study respondents. Anxiety and depression scores were calculated via standard scoring procedures while logistic regression was used to identify the predictors of A&D. SPSS v. 20 was used for data analysis and p < 0.05 was taken as significant.

Results

Seven hundred and fifty pregnant women responded to the survey. The majority of the respondents belonged to age group of 26–35 year (424, 56.4%) and had no formal education (283, 37.6%). Furthermore, 612 (81.4%) of the respondents were unemployed and had urban residencies (651, 86.6%). The mean anxiety score was 10.08 ± 2.52; the mean depression score was 9.51 ± 2.55 and the total HADS score was 19.23 ± 3.91 indicating moderate A&D among the current cohort. Logistic regression analysis reported significant goodness of fit (Chi square = 17.63, p = 0.030, DF = 3), indicating that the model was advisable. Among all variables, age had a significant association when compared with HADS scores [adjusted OR (odds ratios) = 1.23, 95% CI = 1.13–1.62, p < 0.001].

Conclusion

Moderate A&D was reported among the study respondents. Furthermore, age was highlighted as a predictor of A&D. The evidence from this study provides a motion of support programs for anxious and depressed pregnant women. The benefits of implementing good mental health in antenatal care have long-lasting benefits for both mother and infant. Therefore, there is a need to incorporate A&D screening in the existing antenatal programs.

A qualitative study exploring perceptions and attitudes of community pharmacists about extended pharmacy services in Lahore, Pakistan

Background

In recent decades, community pharmacies reported a change of business model, whereby a shift from traditional services to the provision of extended roles was observed. However, such delivery of extended pharmacy services (EPS) is reported from the developed world, and there is scarcity of information from the developing nations. Within this context, the present study was aimed to explore knowledge, perception and attitude of community pharmacists (CPs) about EPS and their readiness and acceptance for practice change in the city of Lahore, Pakistan.

Methods

A qualitative approach was used to gain an in-depth knowledge of the issues. By using a semi-structured interview guide, 12 CPs practicing in the city of Lahore, Pakistan were conveniently selected. All interviews were audio-taped, transcribed verbatim, and were then analyzed for thematic contents by the standard content analysis framework.

Results

Thematic content analysis yielded five major themes. (1) Familiarity with EPS, (2) current practice of EPS, (3) training needed to provide EPS, (4) acceptance of EPS and (5) barriers toward EPS. Majority of the CPs were unaware of EPS and only a handful had the concept of extended services. Although majority of our study respondents were unaware of pharmaceutical care, they were ready to accept practice change if provided with the required skills and training. Lack of personal knowledge, poor public awareness, inadequate physician-pharmacist collaboration and deprived salary structures were reported as barriers towards the provision of EPS at the practice settings.

Conclusion

Although the study reported poor awareness towards EPS, the findings indicated a number of key themes that can be used in establishing the concept of EPS in Pakistan. Over all, CPs reported a positive attitude toward practice change provided to the support and facilitation of health and community based agencies in Pakistan.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2442-6) contains supplementary material, which is available to authorized users.

Massive Diffuse Calcification of the Ascending Aorta and Minimal Focal Calcification of the Abdominal Aorta in Heterozygous Familial Hypercholesterolemia

A 41-year-old woman, the mother of 3 offspring, with likely heterozygous familial hypercholesterolemia, had been asymptomatic until age 38 when angina pectoris and exertional dyspnea appeared leading to the discovery of severe multivessel coronary artery disease and a massively calcified ascending aorta. Coronary bypass grafting using the right and left internal mammary arteries did not alleviate the symptoms. Evidence of overt heart failure subsequently appeared and that led to heart transplantation at age 41. She died 22 days later. The occurrence of massive diffuse calcification of the ascending aorta and minimal focal calcification of the abdominal aorta is rare and in the patient described it appears to be the consequence of heterozygous familial hypercholesterolemia.

Early Pregnancy Ultrasound and Management: Effect of a Multifaceted Training on Physician Knowledge

Vaginal bleeding is a common event in early pregnancy, with 20-40% of pregnancies affected. Prompt diagnosis and management of bleeding is important, both to reduce morbidity and to avoid excessive emotional distress. This was a prospective study of an educational programme aimed at Obstetrics and Gynaecology BST trainees in the National Maternity Hospital, Dublin. The educational programme consisted of didactic lectures, and simulation and practical sessions. A questionnaire reviewing early pregnancy complications was used to assess participant knowledge. Six trainees participated in the programme, with five (83%) answering the questionnaire. The pre-education questionnaire showed a generally poor level of knowledge of early pregnancy complications with 8/50 (16%) questions answered correctly. Following the educational intervention there was a statistically significant increase in participant knowledge with 45/50 (90%) questions answered correctly. A significant increase in participant knowledge of early pregnancy complications followed our multifaceted educational programme. Study limitations exist, however we have shown the potential value of our educational programme.

Intrinsic fluorescence of selenium nanoparticles for cellular imaging applications

Nanoparticles hold great potential in contributing to high-resolution bioimaging as well as for biomedical applications. Although, selenium (Se) nanoparticles (NPs) have been investigated owing to their potential roles in therapeutics, the imaging capability of these NPs has never been explored. This manuscript identifies the intrinsic fluorescence of Se NPs, which is highly beneficial for nanoscale imaging of biological structures. The emission of individual NPs and its evolution with time is explored. The photoluminescence spectra has revealed visible to near infrared emission for Se NPs. The work finally reflects on the role of this intrinsic fluorescence for in vitro imaging and tracking in fibroblast cells, without the need of any additional tags. This technique would overcome the limitations of the conventionally used methods of imaging with tagged fluorescent proteins and dyes, preventing possible adverse cellular effects or phototoxicity caused by the added fluorescent moieties.

Heart transplantation in the Ehlers-Danlos syndrome

We describe a woman with Ehlers-Danlos syndrome and aortic aneurysm who experienced a myocardial infarction due to spontaneous left circumflex coronary artery dissection 3 weeks postpartum. She developed end-stage heart failure and subsequently underwent a successful orthotopic heart transplantation. To our knowledge, this is the first report of a heart transplant performed in an individual with Ehlers-Danlos syndrome.

Crystal phase engineered quantum wells in ZnO nanowires

We report the fabrication of quantum wells in ZnO nanowires (NWs) by a crystal phase engineering approach. Basal plane stacking faults (BSFs) in the wurtzite structure can be considered as a minimal segment of zinc blende. Due to the existing band offsets at the wurtzite (WZ)/zinc blende (ZB) material interface, incorporation of a high density of BSFs into ZnO NWs results in type II band alignment. Thus, the BSF structure acts as a quantum well for electrons and a potential barrier for holes in the valence band. We have studied the photoluminescence properties of ZnO NWs containing high concentrations of BSFs in comparison to high-quality ZnO NWs of pure wurtzite structure. It is revealed that BSFs form quantum wells in WZ ZnO nanowires, providing an additional luminescence peak at 3.329 eV at 4 K. The luminescence mechanism is explained as an indirect exciton transition due to the recombination of electrons in the QW conduction band with holes localized near the BSF. The binding energy of electrons is found to be around 100 meV, while the excitons are localized with the binding energy of holes of ∼5 meV, due to the coupling of BSFs, which form QW-like structures.

Clinical factors associated with left ventricular ejection fraction disparity in patients with left ventricular dysfunction undergoing multimodality imaging

Drug and device therapy for heart failure is increasingly determined based on left ventricular ejection fraction. Significant disparity frequently exists between echocardiographic and nuclear scintigraphic techniques, even when testing is performed nearly simultaneously in clinically stable patients. In 119 patients with left ventricular dysfunction who underwent both echocardiography and stress testing with nuclear imaging within seven days (but with significant disparity in reported left ventricular ejection fraction), we identified four clinical variables which were associated with left ventricular ejection fraction difference. These clinical variables included atrial fibrillation, left ventricular hypertrophy, severe mitral regurgitation and paced rhythm.

Abstract P199: Prevalence of Appropriate Patients for Cardiac Radionuclide Imaging (RNI) Who Are Not Referred for the Procedure

Background: Concern regarding the growth of RNI led to the creation of Appropriate Use Criteria (AUC) as a foundation for evaluating potential overuse. No data exist surrounding the proportion of patients who would be considered appropriate for RNI, but who are not referred for the procedure.

Methods: We reviewed charts of 997 randomly selected patients, regardless of their medical history, seen in the outpatient setting of a single-specialty cardiology group from January to July 2008. Records were reviewed by physicians who were trained to abstract all relevant information to assign an AUC Class; including prior revascularization, recent MI, risk factors, functional capacity, chest pain, anginal control, symptoms and Framingham Risk score. The 2009 Update to the SPECT AUC were used to systematically assign each patient an indication for SPECT of Inappropriate (I), Uncertain (U) or Appropriate (A). Descriptive statistics were calculated to describe the prevalence of AUC ratings.

Results: Of the 997 subjects included, 268 were referred for cardiac RNI and 729 (73%) patients were not. Baseline characteristics of those who were not referred for RNI are reviewed in the table . Among those not referred, 28% (206/729) would have been A, 13% (93/729) U, 42% (308/729) I and 17% (124/729) had insufficient information to classify.

Conclusions: While there are important concerns of RNI overuse, more than 1 in 4 patients not referred for RNI would have meet the AUC criteria for being an appropriate indication. Whether avoiding testing in this group represents judicious use of expensive resources, or these patients outcomes are worse than comparable patients referred for RNI requires follow up and additional research.

Baseline demographics of subjects not undergoing RNI (n= 729) Age; years (mean±SD) 64 ±16 Male 419(57%) Prior Revascularization 253 (35%) CABG>5 yrs 59 (8%) CABG<5 yrs 28 (4%) PCI>2 yrs 112 (15%) PCI<2 yrs 54 (7%) DM 104 (14%) Framingham Risk Score (FRS) Moderate risk 97 (13%) Low risk 229 (31%) Data not available 386 (39%) CHD High Risk (DM or high FRS) 119 (16%) Chest Pain 23 (3%) Anginal equivalent Present 160 (22%) Absent 409 (56%) Data not available 160 (22%) Symptoms Absent 371 (51%) Present 196 (27%) Data not available 162 (22%) Functional capacity Good 457 (63%) Poor 113 (15%) Data not available 161 (22%)

Abstract P105: Clinical Factors Associated With Left Ventricular Ejection Fraction Disparity in Patients With Left Ventricular Dysfunction Undergoing Multimodality Imaging

Background: Drug and device therapy of heart failure is increasingly determined based on left ventricular ejection fraction (LVEF) partition values. Many patients undergo both single photon emission computed tomography (SPECT) and echocardiographic assessment of LVEF. Significant disparity frequently exists between these 2 techniques, even when testing is performed near simultaneously in clinically stable patients.

Objective: We aimed to determine clinical predictors of LVEF disparity in patients undergoing multimodality testing.

Methods: Between January 2006 and July 2007, 2937 patients underwent both echo and SPECT testing within a 7 day period. Of these, 119 patients had an LVEF <50% by 1 or both techniques, and an absolute LVEF difference between the 2 techniques of at least 10%. A control group comprising of 118 patients had an LVEF <50% by 1 or both techniques, and an absolute LVEF difference between the 2 techniques of less than 10%. In a logistic model with a stepwise selection method 30 candidate clinical variables were available to be selected in the model.

Results: The predictive model resulted in five variables: Atrial Fibrillation, Severe mitral regurgitation, Left ventricular hypertrophy, high basal heart rate during echocardiogram and Paced rhythm. The model obtained good predictability(c=0.82) and fit (Hosmer-Lemeshow p=0.51). The point estimates and odds ratios are shown in the figure below.

Conclusions: In patients with LVEF < 50%, atrial fibrillation, severe mitral regurgitation, left ventricular hypertrophy, high basal heart rate during echocardiogram and paced rhythm are associated with a >10% LVEF disparity between the two imaging techniques.

Method for vector characterization of polar liquids using frequency-domain spectroscopy

A device for performing vector transmission spectroscopy on aqueous and polar solvent specimens at terahertz frequencies is presented. The device enables the direct measurement of the complex dielectric function across the terahertz band using a Fourier transform IR spectrometer for lossy solutions. Using microfluidic sampling, specimen handling is straightforward and direct measurements on polar specimens are made possible. The method is scalable to longer or shorter wavelengths.

Polarization insensitive terahertz metamaterial absorber

We present the simulation, implementation, and measurement of a polarization insensitive resonant metamaterial absorber in the terahertz region. The device consists of a metal/dielectric-spacer/metal structure allowing us to maximize absorption by varying the dielectric material and thickness and, hence, the effective electrical permittivity and magnetic permeability. Experimental absorption of 77% and 65% at 2.12 THz (in the operating frequency range of terahertz quantum cascade lasers) is observed for a spacer of polyimide or silicon dioxide respectively. These metamaterials are promising candidates as absorbing elements for thermally based terahertz imaging.

A terahertz polarization insensitive dual band metamaterial absorber

Metamaterial absorbers have attracted considerable attention for applications in the terahertz range. In this Letter, we report the design, fabrication, and characterization of a terahertz dual band metamaterial absorber that shows two distinct absorption peaks with high absorption. By manipulating the periodic patterned structures as well as the dielectric layer thickness of the metal-dielectric-metal structure, significantly high absorption can be obtained at specific resonance frequencies. Finite-difference time-domain modeling is used to design the structure of the absorber. The fabricated devices have been characterized using a Fourier transform IR spectrometer. The experimental results show two distinct absorption peaks at 2.7 and 5.2 THz, which are in good agreement with the simulation. The absorption magnitudes at 2.7 and 5.2 THz are 0.68 and 0.74, respectively.