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Introduction The Sri Lankan economic crisis that began in 2019 led to the suspension of cataract services in many districts. Although humanitarian missions were quick to supply materials, there was a lack of scientific evidence to predict the required intraocular lens power for patients with cataracts. This study aimed to assess the average lens power among patients from Trincomalee district, Sri Lanka, based on sex and age groups. Methods Eye theatre records at District General Hospital Trincomalee were used to assess cataract surgeries between April 2022 and July 2023. Age, sex, side of intraocular lens insertion, and intraocular lens power (selected using ultrasound biometry and the SRK/T formula) were assessed. Results We assessed 1,045 patient records, comprising 476 male patients (46%) and 557 female patients (53%). The intraocular lenses used for the patients ranged from 3 to 30 diopters (D). The average lens power for the entire population was 22.95 D. It was significantly higher for the female patients (23.11 ± 2.519 D) compared with the male patients (22.75 ± 2.250 D) (p = 0.0168). Among the age groups, the highest prevalence of cataracts was in those aged 60-79 years. Conclusions Our findings provide a useful guide for surgical planning in a resource-constrained setting such as the Trincomalee district. While the prevalence of cataracts by age and sex is in accordance with global statistics, the average diopter size is slightly higher compared to Western, African, and other Asian populations., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Pinto et al.)

Previous studies on human acute kidney injury (AKI) following poisoning with potassium permanganate/oxalic acid (KMnO 4 /H 2 C 2 O 4 ), paraquat, and glyphosate surfactant herbicide (GPSH) have shown rapid and large increases in serum creatinine (sCr) that cannot be entirely explained by direct nephrotoxicity. One plausible mechanism for a rapid increase in sCr is oxidative stress. Thus, we aimed to explore biomarkers of oxidative stress, cellular injury, and their relationship with sCr, after acute KMnO 4 /H 2 C 2 O 4 , paraquat, and GPSH poisonings. Serum biomarkers [sCr, creatine (sCn), cystatin C (sCysC)] and urinary biomarkers [cytochrome C (CytoC), 8-isoprostane (8-IsoPs)] were evaluated in 105 patients [H 2 C 2 O 4 /KMnO 4 (N = 57), paraquat, (N = 21), GPSH (N = 27)] recruited to a multicenter cohort study. We used area under the receiver operating characteristics curve (AUC-ROC) to quantify the extent of prediction of moderate to severe AKI (acute kidney injury network stage 2/3 (AKIN2/3)). Patients with AKIN2/3 showed increased levels of CytoC. Early high CytoC predicted AKIN2/3 in poisoning with KMnO 4 /H 2 C 2 O 4 (AUC-ROC 4-8h : 0.81), paraquat (AUC-ROC 4-8h : 1.00), and GPSH (AUC-ROC 4-8h : 0.91). 8-Isoprostane levels were not significantly elevated. Reduced sCn and increased sCr/sCn ratios were observed for 48 h post KMnO 4 /H 2 C 2 O 4 ingestion. Paraquat exhibited a similar pattern (N = 11), however only 3 were included in our study. Increased CytoC suggests there is mitochondrial injury coupled with energy depletion. The increased sCr within 24 h could be due to increased conversion of cellular creatine to creatinine during the process of adenosine triphosphate (ATP) generation and then efflux from cells. Later increases of sCr are more likely to represent a true decrease in kidney function., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Acute kidney injury (AKI) is a major complication of snake envenoming, but early diagnosis remains problematic. We aimed to investigate the time course of novel renal biomarkers in AKI following Russell's viper (Daboia russelii) bites., Methodology/principal Findings: We recruited a cohort of patients with definite Russell's viper envenoming and collected serial blood and urine samples on admission (<4h post-bite), 4-8h, 8-16h, 16-24h, 1 month and 3 months post-bite. AKI stage (1-3) was defined using the Acute Kidney Injury Network criteria. AKI stages (1-3) were defined by the Acute Kidney Injury Network (AKIN) criteria. There were 65 Russell's viper envenomings and 49 developed AKI: 24 AKIN stage 1, 13 stage 2 and 12 stage 3. There was a significant correlation between venom concentrations and AKI stage (p = 0.007), and between AKI stage and six peak biomarker concentrations. Although most biomarker concentrations were elevated within 8h, no biomarker performed well in diagnosing AKI <4h post-bite. Three biomarkers were superior to serum creatinine (sCr) in predicting AKI (stage 2/3) 4-8h post-bite: serum cystatin C (sCysC) with an area under the receiver operating curve (AUC-ROC), 0.78 (95%CI:0.64-0.93), urine neutrophil gelatinase-associated lipocalin (uNGAL), 0.74 (95%CI:0.59-0.87) and urine clusterin (uClu), 0.81 (95%CI:0.69-0.93). No biomarker was better than sCr after 8h. Six other urine biomarkers urine albumin, urine beta2-microglobulin, urine kidney injury molecule-1, urine cystatin C, urine trefoil factor-3 and urine osteopontin either had minimal elevation, and/or minimal prediction for AKI stage 2/3 (AUC-ROC<0.7)., Conclusions/significance: AKI was common and sometimes severe following Russell's viper bites. Three biomarkers uClu, uNGAL and sCysC, appeared to become abnormal in AKI earlier than sCr, and may be useful in early identification of envenoming., Competing Interests: The authors have declared that no competing interests exist.

Background: Chronic kidney disease of uncertain aetiology (CKDu) is one of the major health concerns among agricultural communities in Sri Lanka. Individuals involved in severe agricultural works for their livelihood are highly vulnerable for this disease and patients have been detected with persisting proteinuria at community-level screening. The current study was designed to evaluate the diagnosis of two functional markers of kidney damage using individuals with persisting proteinuria as the baseline., Methods: One hundred and fifty hard-working agricultural farmers from high-prevalence area for CKDu (Madawachchiya) were screened three times for proteinuria; 66 proteinuric and 21 non-proteinuric were identified as the baseline classification. Selected individuals were analysed further for creatinine, protein and cystatin C in urine and creatinine, cystatin C in serum. Urine protein-to-creatinine ratio (UP/UC) was calculated., Results: Based on creatinine and cystatin C cut-off levels in serum, individuals were classified as high or normal. Diagnosis of two functional markers (creatinine and cystatin C) were evaluated using receiver operating characteristic (ROC) curve and in terms of sensitivity and specificity using UP/UC as the baseline. Creatinine and cystatin C-based eGFR (estimated Glomerular filtration rate) levels were calculated, and Pearson's correlation coefficient was determined between different eGFR measurements using UP/UC. Mean (SD) UP/UC ratio, serum creatinine, and serum cystatin C levels of the proteinuric subjects were 129.0 (18.4) mg/mmol, 1.35 (0.39) mg/dL, 1.69 (0.58) mg/L. For non-proteniuric individuals, the results were found to be 14.4 (2.28), 1.22 (0.40) mg/dL, 0.82 (0.25) mg/L. The ROC analysis showed excellent accuracy in using cystatin C for identifying proteinuric patients than creatinine area under the curve (AUC): 0.9675, P < 0.001). Cut-off points were identified as 1.015 mg/dL for serum creatinine and 0.930mg/L for cystatin C. Furthermore, cystatin C based Hoek formula showed the better correlation (0.635, P < 0.001) with UP/UC compared with creatinine based modification of diet in renal disease (MDRD) formula., Conclusion: The study showed elevated serum cystatin C in patients with persisting proteinuria compared with non-responding serum creatinine. Moreover, cystatin C-based eGFR equations were more accurate to determine the kidney function than serum creatinine in proteinuric patients who are vulnerable for CKDu in high-prevalence areas., Competing Interests: Conflicts of Interest None.

The 20-minute whole blood clotting test (WBCT20) is used as a bedside diagnostic test for coagulopathic snake envenoming. We aimed to assess the performance of the WBCT20 in diagnosis of venom induced consumption coagulopathy (VICC) in Russell's viper envenoming. Adult patients admitted with suspected snake bites were recruited from two hospitals. WBCT20 and prothrombin time (PT) test were performed on admission. WBCT20 was done by trained clinical research assistants using 1 ml whole blood in a 5 ml borosilicate glass tube with a 10 mm internal diameter. The PT was measured by a semi-automated coagulation system and international normalised ratio (INR) calculated. VICC was defined as present if the INR was >1.4. The diagnostic utility of WBCT20 was determined by calculating the sensitivity and specificity of the WBCT20 on admission for detecting VICC. There were 987 snake bites where both WBCT20 and PT were done on admission samples. This included 79 patients (8 %) with VICC. The WBCT20 was positive in 65/79 patients with VICC (sensitivity 82 %; 95 % confidence interval [CI]: 72-90 %) and was falsely positive in 13/908 with no coagulopathy. The WBCT20 was negative in 895/908 snake bites with no coagulopathy (specificity: 98 % 95 % CI: 97-99 %) and was falsely negative in 14/79 with VICC. Using trained clinical staff, the WBCT20 test had a relatively good sensitivity for the detection of VICC, but still missed almost one fifth of cases where antivenom was potentially indicated.

Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 10(12) e/cm(2) or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene's properties. Here we demonstrate strong (1.33 × 10(13) e/cm(2)), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 10(13) e/cm(2) when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. The ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.

We investigate the effect of confinement on the crystalline microstructure of the polymer component of polymer : fullerene bulk heterojunction thin films using grazing incidence wide angle X-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920 nm to <20 nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thicker than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors.

Background: Traffic policemen are identified to be at a higher risk of exposure to air pollution and its contaminants such as lead. A study done prior to the introduction of unleaded petroleum in Sri Lanka revealed a mean blood lead level of 53.07 μg/dL, which was well above the Center for Disease Control defined acceptable safe levels. This study aimed to determine whether unleading of fuel has made an impact on the blood lead levels of traffic police working in an urban area with high traffic density., Method: A cross-sectional survey of 168 traffic police personnel working within Colombo city limits of Sri Lanka, a high traffic density area, was conducted. Blood lead levels of participants were measured using nitric acid, perchloric acid ashing method and atomic absorption spectrophotometry. An interviewer administered questionnaire was used for a targeted history and examination., Results and Discussion: Mean age of the sample population was 37 years. Thirty eight percent had detectable levels of lead in blood and 24.4% of the study sample had blood lead levels above Centre for disease control defined safe limits. Sample mean was 4.82 μg/dL (95% CI 3.58-6.04), and this is a 91% overall reduction when compared to data prior to unleading. Neither symptoms nor signs of classic lead toxicity showed significant correlation with toxic lead levels., Conclusion: Lead poisoning though still present in the high risk traffic warden population shows a considerable reduction following unleading. The need to have a low threshold to suspect lead poisoning is highlighted by the non-specific nature of the symptoms and signs of lead poisoning and its lack of association even in those found to have elevated lead levels. Further studies are required to elucidate a cause for the prevalence of lead poisoning despite cessation of using lead as an additive in petroleum.

Objective: Antiseptics are widely used in wound management to prevent or treat wound infections due to their proven wound healing properties regardless of their cytotoxicity. The objective of this study was to determine the bactericidal effects of three antiseptics on pathogens known to cause wound infections., Method: The study was carried out at a tertiary care hospital and a university microbiology laboratory in Sri Lanka in 2013. The three acids (acetic acid, ascorbic acid and boric acid) in increasing concentration (0.5%, 0.75% and 1%) were tested against bacterial suspensions equivalent to 0.5 McFarland standard. The Bacteria isolates used were isolated from wound and standard strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa., Results: There were 33 (68.8%) Coliforms, 10 (20.8%) Pseudomonas species, and 5 (10.4%) strains of Staphylococcus aureus. Acetic acid at concentration of 0.5% inhibited growth of 37 (77%) and 42 (87.5%) of tested isolates when exposed for 30 and 60 minutes, respectively. However 100% inhibition was achieved at four hours. At a concentration of 0.75%, 40 (83.3%) and 44 (91.7%) were inhibited when exposed for 30 and 60 minutes, respectively, with 100% inhibition at 4 hours. At concentration of 1%, 46 (95.8%) inhibition was seen at 30 minutes and 100% inhibition at 60 minutes. Ascorbic acid, at 0.5% and 0.75 % concentrations, inhibited growth of 45(93.7%) and 47(97.9%) of isolates respectively when exposed for 30 minutes. At these two concentrations, 100% inhibition was achieved when exposed for one hour. At 1% concentration, 100% inhibition was achieved at 30 minutes. Boric acid did not show bactericidal effect at concentrations of 0.5%, 0.75 % and 1%. Pseudomonas species were inhibited at 30 minutes by 0.5% acetic acid. Bactericidal effect against all the standard strains was seen with three acids at each concentration tested from 30 minutes onwards, Conclusion: Ascorbic acid was bactericidal for all organisms tested within the shortest exposure time at the lowest concentration compared to other two acids. Despite promising bactericidal effects, further studies warrant, as ongoing debates on toxicity of acids on tissue epithelialisation. Application of antiseptics for a shorter duration could overcome this problem without losing bactericidal activity., Declaration of Interest: The authors have no conflict of interest and no funding was received for this study.

Background: The aim of the study was to identify the epidemiology of chronic kidney disease of uncertain etiology in Sri Lanka., Methods: A cross-sectional study was carried out by analyzing health statistics, and three cohort studies were conducted (n = 15 630, 3996, and 2809) to analyze the demographic information, age-specific prevalence, etiology, and stage of presentation. We screened 7604 individuals for chronic kidney disease of uncertain etiology., Results: The results showed that the male:female ratio was 2.4:1, the mean age of patients was 54.7 ± 8 years, 92% of the patients were farmers, and 93% consumed water from shallow dug wells. Familial occurrence was common (36%). The prevalence of chronic kidney disease in different age groups was 3% in those aged 30-40 years; 7% in those aged 41-50 years, 20% in those aged 51-60 years, and 29% in those older than 60 years. Chronic kidney disease of uncertain etiology was diagnosed in 70.2% of patients, while 15.7% and 9.6% were due to hypertension and diabetic mellitus, respectively. The majority of patients were stage 4 (40%) at first presentation, while 31.8% were stage 3 and 24.5% were stage 5. Stage 1 and 2 presentation accounted for only 3.4%., Conclusions: Low prevalence of CKDU was noticed (1.5%) among those who consumed water from natural springs. Prevalence was highest among males, rice farming communities, and those presenting at later disease stages.

Background: Snake bite is a common problem in the North Central province of Sri Lanka. Common krait (Bungarus careuleus), Ceylon krait (Bungarus ceylonicus), Cobra (Naja naja), Russell's viper (Daboia russelii), Saw-scaled viper (Echis carinatus) and Hump-nosed pit viper (Hypnale hypnale) are the six species of venomous land snakes in Sri Lanka. A significant number of adults and children are bitten by snakes every year. However, the majority of research studies done in Sri Lanka and other countries show adults bitten by snakes and studies describing children bitten by snakes are very sparse., Methods: A descriptive cross sectional study was performed in the Teaching Hospital Anuradhapura in the North Central Province of Sri Lanka from May 2010 to 2011 May to describe the characteristics associated with cases of snake bite., Results: There were 24 males and 20 females. The highest numbers of bites (48%) were in the range of ages 6-12 years. The majority of the bites occurred between 6 pm to 6 am (59%).The foot was the most common bitten site (48%). Out of all the venomous bites, the Hump-nosed pit viper (Hypnale hypnale) accounted for the highest number (44%) and Russell's viper (Daboia ruselii) accounted for the second highest number (27%). A significant number of venomous bites occurred indoors while sleeping (22%). Antivenom serum was given to (39%) of venomous bites. Deaths occurred in (11%) of the venomous bites., Conclusions: Hump-nosed pit viper (Hypnale hypnale) accounted for the highest number of venomous bites. Majority of the bites occurred between 6 pm and 6 am. Foot was the most common bitten site. A significant number of venomous bites occurred indoor while sleeping. Antivenom serum was given to a significant number of venomous bites. Educating the public on making their houses snake proof and using a torch when going out during night time will help in the prevention of getting bitten by snakes.

The effects of thin-film confinement on the material properties of ultrathin polymer (electron donor):fullerene (electron acceptor) bulk heterojunction films can be important for both fundamental understanding and device applications such as thin-film photovoltaics. We use variable angle spectroscopic ellipsometry and near edge X-ray absorption fine structure spectroscopy to measure the optical constants, donor-acceptor volume fraction profile, and the degree of interchain order as a function of the thickness of a poly(3-hexythiophene-2,5-diyl) and phenyl-C61-butyric acid methyl ester bulk heterojunction film. We find that as the thickness of the bulk heterojunction film is decreased from 200 nm to the thickness confinement regime (less than 20 nm), the vertical phase segregation gradient of the donor and acceptor phases becomes less pronounced. In addition, observing the change in exciton bandwidth and the shift of absorption resonances (0-0 and 0-1) relative to neat donor and acceptor films, we find that the conjugation length and disorder in ultrathin films (20 nm) are less affected than thicker (200 nm) films by the addition of fullerene into the polymer. We believe that these findings could be important for discovering methods of precisely controlling the properties of bulk heterojunction films with crucial implications for designing more efficient organic-based photovoltaics.

Rationale: Bacterial flora can be isolated from many semen samples of subfertile males. Bacteriospermia can compromise the outcome of intra uterine insemination (IUI) by contaminating the post-processed sperm sample., Objectives: The objective of the present study is to determine the efficacy of penicillin and streptomycin in eliminating the bacteria from semen samples in the sperm processing procedure, and to assess the effects of antibiotics on sperm motility, survivability, and pregnancy rates., Design and Settings: A prospectively controlled study was carried out using couples undergoing IUI with their informed consent., Intervention: Sperm processing using the swim-up technique in penicillin and streptomycin supplemented culture medium., Subjects and Methods: Couples were consecutively allocated in two groups for sperm processing (a) Group AB+ (antibiotics supplemented culture medium, n = 33) and (b) Group AB- (antibiotic free culture medium, n = 33). Semen culture was performed before and after sperm processing. Sperm motility was assessed immediately after processing and after 24 h of incubation., Results: Bacterial isolates were found in 20 (60.6%) and 22 (66.1%) of samples before processing in Groups AB+ and AB- respectively. Addition of antibiotics resulted in completely eliminating non-specific bacteria from semen samples without affecting sperm motility. In vitro survival rate of sperm enhanced in AB+ group compared with AB- group (motile sperm after 24 h), 62.21% (standard deviation [SD]: 37.27) versus 41.36% (SD: 30.78), P = 0.012. Pregnancy rate, was comparable between two groups (9% in Group AB+ vs. 6% in Group AB-, P = 0.45)., Conclusion: Penicillin streptomycin combination could completely eliminate non-specific bacteria from semen samples during sperm processing in this population. The types of antibiotics and dosage used did not seem to have any harmful effects on human sperm.

The electronic structure and magnetism of nanocrystalline graphite prepared by ball milling of graphite in an inert atmosphere have been investigated using valence band spectroscopy (VB), core level near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and magnetic measurements as a function of the milling time. The NEXAFS spectroscopy of graphite milled for 30 hours shows simultaneous evolution of new states at ~284.0 eV and at ~290.5 eV superimposed upon the characteristic transitions at 285.4 eV and 291.6 eV, respectively. The modulation of the density of states is explained by evolution of discontinuities within the sheets and along the fracture lines in the milled graphite. The magnetic measurements in the temperature interval 2-300-2 K at constant magnetic field strength show a correlation between magnetic properties and evolution of the new electronic states. With the reduction of the crystallite sizes of the graphite fragments, the milled material progressively changes its magnetic properties from diamagnetic to paramagnetic with contributions from both Pauli and Curie paramagnetism due to the evolution of new states at ~284 and ~290.5 eV, respectively. These results indicate that the magnetic behaviour of ball-milled graphite can be manipulated by changing the milling conditions.

We demonstrate a novel, multi-purpose optoelectronic characterization technique to quantify light trapping and photoinduced charge generation and extraction in photovoltaics and other multilayer thin-film optoelectronic devices. The technique measures the photogenerated current created via the selective evanescent coupling of incident light into each of the guided modes of an optoelectronic device. In analogy to the internal quantum efficiency commonly used to characterize photovoltaics (the ratio of photogenerated electrons extracted from the device to photons absorbed by the device for normally incident light), we define the guided-mode internal quantum efficiency (GIQE) as the ratio of photogenerated electrons extracted from the device to the photons absorbed by the device for a specific guided mode. We complement the measurement of GIQE with computational modeling to calculate the electromagnetic field distribution within the various layers of the device, enabling us to separate the contribution to the GIQE of the absorption in the photoactive layer from parasitic absorption in other layers. By separately quantifying the quantum efficiency of each guided mode, this technique enables improved optimization and design of optoelectronic devices, including photovoltaics that utilize waveguiding and light-trapping. Additionally, since the electromagnetic field of each guided mode has a unique spatial distribution within the photoactive layer, this technique also provides insight into the spatial distributions of charge-carrier extraction, regions of disorder, trap states, and defects within the photoactive layer.

Methemoglobin (MetHb) is a significant clinical problem for some poisonings. Its measurement is a problem as both formation and reduction of MetHb can occur even after sampling with time. The objective of this study was to discover a method to stabilize the blood samples for the determination of MetHb. First, hemolysates were prepared by diluting the MetHb blood samples with phosphate buffers under different pH values. The samples were stored at 4-8 °C and a day-to-day variability in the amount of MetHb was determined using the method described by Evelyn and Malloy. The results show that there is a significantchange in the amount of MetHbstored in both KH2PO4/Na2HPO4 and KH2PO4/Na2HPO4 .2H2O buffer solutions at pH of 6.7 and 6.9. Buffer solution containing phosphate composition of KH2PO4/Na2HPO4 ·2H2O (pH=7.0) gives relatively stable values for MetHb during the storage and the amount of MetHb samples in the buffer solution retain constant up to 9 days. Therefore, stabilized MetHb blood samples can be prepared using KH2PO4/Na2HPO4 ·2H2O buffer solution (pH=7) with non-ionic detergent and the samples can be stored for several days at 4-8 °C., (© 2011 Wiley-Liss, Inc.)

Study Objective: Methemoglobinemia after pesticide poisoning is associated with a mortality of 12% in Sri Lanka. Treatment is complicated by the lack of laboratory facilities. We aimed to develop and validate a low-cost bedside test for quantitative estimation of clinically significant methemoglobin to be used in settings of limited resources., Methods: A method to reliably produce blood samples with 10% to 100% methemoglobin was developed. Freshly prepared methemoglobin samples were used to develop the color chart. One drop (10 microL) of prepared methemoglobin sample was placed on white absorbent paper and scanned using a flatbed Cannon Scan LiDE 25 scanner. The mean red, green, and blue values were measured with ImageJ 1.37v. These color values were used to prepare a color chart to be used at the bedside. Interobserver agreement was assessed against prepared samples. The results from clinical use were compared with formal methemoglobin measurements., Results: The red color value was linearly related to percentage methemoglobin (R(2)=0.9938), with no effect of absolute hemoglobin concentration. Mean interobserver (N=21) agreement and weighted kappa for scanned methemoglobin spots using the color chart were 94% and 0.83, respectively. Mean interobserver (N=9) agreement and weighted kappa for a freshly prepared methemoglobin sample with the chart were 88% and 0.71, respectively. Clinical use of the color chart also showed good agreement with spectrometric measurements., Conclusion: A color chart can be used to give a clinically useful quantitative estimate of methemoglobinemia., (Copyright (c) 2009 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.)

A near-infrared sensitive hybrid photovoltaic system between PbS nanocrystals (PbS-NCs) and C(60) is demonstrated. Up to 0.44% power conversion efficiency is obtained under AM1.5G with a short circuit current density (J(sc)) of 5 mA cm(-2) when the PbS-NC layer is treated in anhydrous methanol. The observed J(sc) is found be approximately one-third of the maximum expected from this hybrid configuration, indicating the potential for further optimization. Crucial for device operation, a smooth film of nanocrystals is seen to form on the hole transporting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer deposited on the transparent electrode, facilitated through an ionic interaction between nanocrystal capping ligands and the PEDOT:PSS. The formation of the open circuit voltage in this system is seen to be influenced by an interfacial dipole formed at the hole-extracting electrode, providing insights for further optimization.

Organic-inorganic hybrid heterojunctions have potential as the basis for future photovoltaic devices. Herein, we report the results of investigations exploring the possibility of using pentacene and tetracene as photoelectron donors in conjunction with PbS nanocrystals (PbS-NCs). Photoinduced charge transfer was probed using external quantum efficiency measurements on acene:PbS-NC hybrid photovoltaic devices in conjunction with photoluminescence studies of the corresponding bilayer films. It is shown that photoelectron transfer from pentacene to the PbS-NCs is inefficient as compared to that between tetracene and PbS-NCs. The latter case can be rationalized in terms of the energy level alignment at the heterojunction assuming a common vacuum level. However, in the case of pentacene:PbS-NC junctions an interfacial energy level shift must be considered in order to explain the observations.