Experimental evidence on promotion of electric and improved biomass cookstoves.

Improved cookstoves (ICS) can deliver "triple wins" by improving household health, local environments, and global climate. Yet their potential is in doubt because of low and slow diffusion, likely because of constraints imposed by differences in culture, geography, institutions, and missing markets. We offer insights about this challenge based on a multiyear, multiphase study with nearly 1,000 households in the Indian Himalayas. In phase I, we combined desk reviews, simulations, and focus groups to diagnose barriers to ICS adoption. In phase II, we implemented a set of pilots to simulate a mature market and designed an intervention that upgraded the supply chain (combining marketing and home delivery), provided rebates and financing to lower income and liquidity constraints, and allowed households a choice among ICS. In phase III, we used findings from these pilots to implement a field experiment to rigorously test whether this combination of upgraded supply and demand promotion stimulates adoption. The experiment showed that, compared with zero purchase in control villages, over half of intervention households bought an ICS, although demand was highly price-sensitive. Demand was at least twice as high for electric stoves relative to biomass ICS. Even among households that received a negligible price discount, the upgraded supply chain alone induced a 28 percentage-point increase in ICS ownership. Although the bundled intervention is resource-intensive, the full costs are lower than the social benefits of ICS promotion. Our findings suggest that market analysis, robust supply chains, and price discounts are critical for ICS diffusion.

Reductions in indoor black carbon concentrations from improved biomass stoves in rural India.

Deployment of improved biomass burning cookstoves is recognized as a black carbon (BC) mitigation measure that has the potential to achieve health benefits and climate cobenefits. Yet, few field based studies document BC concentration reductions (and resulting human exposure) resulting from improved stove usage. In this paper, data are presented from 277 real-world cooking sessions collected during two field studies to document the impacts on indoor BC concentrations inside village kitchens as a result of switching from traditional stoves to improved forced draft (FD) stoves. Data collection utilized new low-cost cellphone methods to monitor BC, cooking duration, and fuel consumption. A cross sectional study recorded a reduction of 36% in BC during cooking sessions. An independent paired sample study demonstrated a statistically significant reduction of 40% in 24 h BC concentrations when traditional stoves were replaced with FD stoves. Reductions observed in these field studies differ from emission factor reductions (up to 99%) observed under controlled conditions in laboratory studies. Other nonstove sources (e.g., kerosene lamps, ambient concentrations) likely offset the reductions. Health exposure studies should utilize reductions determined by field measurements inside village kitchens, in conjunction with laboratory data, to assess the health impacts of new cooking technologies.

Change in hepatitis C virus clades: a cross-sectional study of chronic HCV patients in Pakistan from 2000-2010.

The changing pattern in hepatitis C virus (HCV) clades overtime is not well known in Pakistan. To find out the changing pattern of different HCV clades over time in this country 22,125 patients were genotyped and tracked for a period of 11 years (2000-2010). A changing pattern in HCV clades was seen in this region during the study period. Sub-clade 3a remained the dominant sub-clade circulating in different areas of the country in the study era. HCV sub-clade 3a demonstrated significantly high correlation with time (p < 0.05) whereas undetermined clades were seen with statistically non-significant correlation with time (years). All the other clades showed negative correlation with time. In general a significant decline was observed in the percentages of HCV clades 2, 4, 5 and 6 (p < 0.001). Among sub-clades, HCV 1a, 2c, 2b and 3b significantly decreased overtime (p < 0.05), while an increase has been observed for HCV 3a sub-clade and mixed clades (p <0.001). The ratio of undetermined clades remained constant over the study period. In conclusion, a changing pattern of HCV clades was observed over the 11-year study period, and this changed pattern might have direct impact on HCV disease outcome.

Preparation and characterization of a novel bioactive restorative composite based on covalently coupled polyurethane-nanohydroxyapatite fibres.

Nanohydroxyapatite (n-HAp) was prepared using a sol-gel method. n-HAp powder was obtained from the gel form by heat treatment followed by grinding using ball milling. A novel polyurethane composite material was prepared by chemically binding the hydroxyapatite to the diisocyanate component in the polyurethane backbone through solvent polymerization. The procedure involved the stepwise addition of monomeric units of the polyurethane and optimizing the reagent concentrations. The resultant composite material was electrospun to form fibre mats. The fibres were less than 1mum in thickness and contained no beads or irregularities. Chemical structural characterization of both the ceramics and the novel polymers were carried out by Fourier transform infrared and Raman spectroscopy. X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy and Brunauer-Emmett-Teller surface area analysis were also employed to observe the crystal lattice and size and surface area of the n-HAp. Further characterization (by energy-dispersive X-ray analysis and SEM) of the spun fibres revealed the presence of elements associated with hydroxyapatite and polyurethane without the presence of any loose particles of hydroxyapatite, indicating the formation of the covalent bond between the ceramics and the polymer backbone.

Methylational urinalysis: a prospective study of bladder cancer patients and age stratified benign controls.

Tumour suppressor gene (TSG) methylation has been proposed as a diagnostic marker for urothelial cancer (UC). Here, we compare the frequency of urinary TSG methylation in young and elderly patients, with and without UC. Urine samples were obtained prospectively from 35 UC patients, 35 benign controls over the age of 70 years and 34 healthy volunteers under the age of 40 years. Methylation analysis was performed for eight gene promoters using quantitative methylation-specific PCR. Methylation was detected in urine DNA from all three patient groups. The highest frequencies were seen in UC patients. Significantly less methylation was present in control samples than UC cases for RASSF1a and APC (P < 0.034). The 'methylation index' and level of methylation was highest in the UC group and lowest in the young control group. A marker panel of RASSF1a, E-cad and APC generated a sensitivity of 69%, a specificity of 60% and a diagnostic accuracy of 86%. TSG methylation is detectable in urine DNA from patients with and without bladder cancer. The frequency and extent of methylation appears to increase with age and malignancy. The lack of tumour specificity suggests that further investigation is required before this test is introduced into clinical practice.

Lactate dehydrogenase-B is silenced by promoter hypermethylation in human prostate cancer.

In order to identify novel candidates associated with prostate cancer metastasis, we compared the proteomic profile of the poorly metastatic human prostate cancer cell line LNCaP, with its highly metastatic variant LNCaP-LN3, by two-dimensional gel electrophoresis. A major protein spot (pI of 5.9 and molecular weight of 37 kDa) was seen in LNCaP cells, but not in LNCaP-LN3 cells and was identified as lactate dehydrogenase-B (LDHB), by tandem mass spectrometry. Furthermore, enzyme kinetic assays and zymography showed a higher LDH enzyme activity in LNCaP cells compared with LNCaP-LN3. Bisulphite-modified DNA sequencing showed promoter hypermethylation in LNCaP-LN3 cells but not in LNCaP, Du145, PC3, CWR22 or BPH45 cells. Treatment of LNCaP-LN3 cells with 5'-azacytidine caused re-expression of LDHB transcripts. In tissues, LDHB promoter hypermethylation occurred at a higher frequency in prostate cancer, 14/ 31 (45%), compared to adjacent nonmalignant or benign tissue, 2/19 (11%) (P < 0.025). Immunohistochemistry showed a higher frequency of LDHB expression in benign or non-malignant tissues, 59/ 73 (81%), compared to cancer cases, 3/53 (6%) (P < 0.001). Absent LDHB expression was also seen in 7/7 (100%) cases of metastatic cancer in bone. Our data are the first to show loss of LDHB expression in prostate cancer, the mechanism of which appears to involve promoter hypermethylation.

Controlled release of chlorhexidine diacetate from a porous methacrylate system: supercritical fluid assisted foaming and impregnation.

The release of chlorhexidine diacetate (CX) from a self-curing polymeric system based on poly(ethylmethacrylate) and tetrahydrofurfurylmethacrylate (PEM/THFM) was developed in this study. Supercritical fluid assisted impregnation and foaming was employed for preparing porous CX-PEM/THFM drug release system. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) show that the crystallinity of CX significantly decreased after supercritical processing, whilst Raman spectroscopy suggested a hydrogen bonding interaction between the CX and PEM in the product. A UV-Vis dissolution study revealed that the drug release rate is almost as seven times faster in the SCF processed drug delivery system than conventional cured samples.

Synthesis of poly(sebacic anhydride)-indomethacin controlled release composites via supercritical carbon dioxide assisted impregnation.

Poly(sebacic anhydride), PSA and indomethacin drug composite (DC) formulations were prepared using supercritical CO(2) (sc-CO(2)) aided mixing. The effect of the experimental temperature and sebacic acid purity on the physical properties of PSA-indomethacin DCs was investigated using a range of analytical techniques. The nature of the PSA-indomethacin interaction in composites after processing in sc-CO(2) under various conditions was investigated using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and powder X-ray diffraction (XRD) methods, respectively. The results indicate that processing at 130 degrees C of a 4:1 (w/w) ratio PSA-indomethacin mixture, renders the indomethacin amorphous and dispersed within the polymer matrix. The primary interaction between PSA and indomethacin appears to be hydrogen bonding between the carboxylic acid OH of indomethacin and the carbonyl group of PSA. In vitro dissolution studies revealed that the processed composites exhibit a substantially enhanced dissolution rate compared to the physical mixtures. Also, through the control of experimental conditions, the initial burst effect of the drug release was largely alleviated. Instead, the erosion of PSA (zero order degradation) became the dominant factor in controlling the drug release rate.

Fabrication and in vivo evaluation of hydroxyapatite/carbon nanotube electrospun fibers for biomedical/dental application.

The aim was to synthesize bioactive electrospun fibers for biomedical and dental application with improved biocompatibility. In situ precipitation of nano-hydroxyapatite (nHA) was performed with various concentrations (0.5%, 1%, 2%, 3%, and 5% wt/wt) of functionalized multi-walled-carbon nanotubes (MWCNTs) by using microwave irradiation technique. The obtained composites were characterized by Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC), and the cylindrical discs were made for mechanical testing. The failure behavior was analyzed by Scanning Electron Microscope (SEM). CNT and HA/CNT were silanized with γ-methacryloxypropyl-trimethoxysilane (MPTS) and mixed with polyvinyl alcohol (10% wt./vol.) and electrospun to fabricate fibers. The biocompatibility of both fibers was accessed by their effects on angiogenesis in a chick chorioallantoic membrane (CAM) assay. The electrospun fibers were analyzed by SEM. FTIR confirmed the structural behavior of pre and post-silanized HA/CNT. XRD showed the phase purity and crystallinity before and after heat treatment. Mechanical properties showed that 3% loaded HA/CNT has higher compressive strength (100.5±5.9MPa) compared to others and the failure behavior exhibited dispersion of CNT in HA matrix. The HA/CNT electrospun fibers showed significantly more blood vessels formation compared to CNT fibers. These HA/CNT electrospun fibers showed promising results in terms of biocompatibility and with improved mechanical properties of CNT reinforced composites, they can be used in load bearing clinical applications.

Supercritical fluid assisted impregnation of indomethacin into chitosan thermosets for controlled release applications.

Supercritical carbon dioxide (sc-CO(2)) was used to impregnate indomethacin (a non-steroidal anti-inflammatory drug) into chitosan thermosets for the preparation of controlled release formulations. The products were analyzed by a range of methods including powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of the experimental temperature and pressure of the sc-CO(2) on the thermal behavior of chitosan-indomethacin drug composites (DCs) was investigated via differential scanning calorimeter (DSC). The interaction of chitosan and indomethacin after impregnation was then studied by Fourier transform infrared (FTIR) and Raman spectroscopy, respectively. Our results suggest that the supercritical fluid impregnation process results in indomethacin being amorphously dispersed within the chitosan matrix. FTIR data suggest that the aliphatic carbonyl group of indomethacin interacts with the NH(2) group of the chitosan backbone. In vitro dissolution studies (via UV-vis spectroscopy) reveal that the dissolution rate of indomethacin substantially increases after processing in sc-CO(2), particularly, under the experimental conditions 20.7 MPa and 70 degrees C.

Allelotypes of primary cutaneous melanoma and benign melanocytic nevi.

A multistep genetic model of tumorigenesis, based on genetic alterations in benign and primary malignant lesions, has been proposed for neoplasms such as colonic carcinoma. However, evidence for a similar genetic progression in melanoma has relied heavily on findings in cultured lesions or metastases. We have investigated every autosomal arm for loss of heterozygosity in 41 primary cutaneous melanomas and 32 benign melanocytic nevi, and have investigated several chromosome arms that show loss in melanoma in 27 Spitz nevi (a nevus with histological similarities to melanoma). Loss of heterozygosity in primary melanoma was identified most frequently on chromosomes 9p (46%) at loci near the p16INK4 gene, 10q (31%), 6q (31%), and 18q (22%); loss of these chromosome arms were related to the progression of the melanoma. Only two benign melanocytic nevi (both of which showed atypical features on histology) demonstrated genetic alterations, including p9 loss in one case. In addition, two Spitz nevi contained interstitial deletions on chromosome 9p. Our findings show that loss of heterozygosity of 9p is not confined to melanoma, but that other uncultured melanocytic lesions can also display loss of this chromosome arm, and that other genetic changes (e.g., loss of 10q, 6q, and 18q) may be important in conveying the malignant phenotype to melanoma.

Genetic change in actinic keratoses.

Actinic keratoses (AKs) are small scaly red areas of skin characterised histologically by dysplasia, a minority of which are thought to be precursors of squamous cell carcinoma (SCC), and which show a high frequency of regression. Surprisingly, in view of their benign clinical course, they show a high frequency of loss of heterozygosity (LOH) with a median loss of four loci with almost 20% of lesions showing loss of eight or more alleles, as well as frequent p53 mutation. Loss was common on 3p (31%), 9p (39%), 9q (22%), 13q (52%), 17p (64%) and 17q (46%), and allele loss correlated with dysplasia. Topological disturbance of p21WAF1/CIP1 expression correlated with allele loss but was also seen together with increased wild-type p53 expression and an increase in the fraction of cycling cells in the absence of allele loss or p53 mutation, and is likely to represent an early change. P21WAF1/CIP1 expression appeared independent of p53 status. The frequency of LOH in AKs exceeded that of (invasive) SCCs suggesting that the relation between the accumulation of genetic change and behaviour for non-melanoma skin cancer is not straightforward.

Formation and characterization of porous indomethacin-PVP coprecipitates prepared using solvent-free supercritical fluid processing.

Supercritical carbon dioxide (sc-CO2) was used to prepare coprecipitates of indomethacin (IM) and poly(vinylpyrrolidone) (PVP) with the aim to improve the dissolution rate of IM. The coprecipitates of IM and PVP at various proportions were prepared using a stirred batch reactor containing sc-CO2 as a gas saturated solution (i.e., the compressible CO2 is dissolved in the molten compound). Temperatures between 40 and 90 degrees C and pressure of 150 or 200 bar were employed. The coprecipitates prepared at 75 degrees C and 150 bar were characterized using differential scanning calorimetry (DSC), powder X-ray diffraction (PXD), scanning electron microscopy (SEM), and dissolution testing. The results suggested that IM was totally amorphous at PVP weight fraction of 0.80 and above (indeed, as a molecular composite in which the drug molecules interact with the polymer backbone). As the PVP weight fraction decreased, IM displayed an increasing amount of crystalline material. The SEM photographs of coprecipitates showed a foamed and porous structure. The dissolution rate of IM was increased by incorporation of PVP. IM and PVP at various weight fractions exhibited comparatively higher dissolution rates than that of crystalline IM alone. The sc-CO2 based process produced a solvent free, completely amorphous porous IM solid dispersion with a rapid dissolution rate.

Deletion mapping of chromosome 3p and 13q and preliminary analysis of the FHIT gene in human nonmelanoma skin cancer.

Loss of heterozygosity of chromosomes 3p and 13q occurs frequently in human cutaneous squamous cell neoplasms, suggesting the presence of one or more tumor suppressor genes on these chromosome arms that may be involved in the pathogenesis of this tumor type. To date there is no clear evidence in cutaneous tumors where these putative genes are located. In this study we have analyzed 20 squamous cell neoplasms that show allelic loss at chromosome 13q, and 22 squamous cell neoplasms that show allelic loss at chromosome 3p, in an attempt to define the smallest area of deletion. One commonly deleted region was identified on chromosome 13 that centred around 13q13, and two commonly deleted regions were identified on chromosome 3 that mapped to 3p24-pter and 3p12-p14.1. Our findings suggest the presence of at least one tumor suppressor gene on chromosome 13 and two tumor suppressor genes on chromosome 3p that may be involved in the progression of these neoplasms. Deletions within the Fragile Histidine Triad gene, located at 3p14.2, have been reported in several tumors, leading to the suggestion that this gene is involved in tumor development. To evaluate the role of the Fragile Histidine Triad gene in nonmelanoma skin cancer, we have used reverse transcriptase polymerase chain reaction analysis to screen for deletions in 16 tumors (five basal cell carcinomas, five squamous cell carcinomas, five actinic keratoses, and one case of Bowen's disease) and HaCaT and A431 cell lines. A normal transcript was found to be expressed in 14 of 16 tumors and both cell lines. This suggests that the Fragile Histidine Triad gene is not a common target for deletion in Bowen's disease and the cell lines HaCaT and A431.

Microsatellite instability in human non-melanoma and melanoma skin cancer.

Microsatellite instability secondary to replication errors (RER), characterized by length changes at repetitive loci scattered throughout the genome, is a recently recognized genetic mechanism important in the development of some human cancers. Although RER has been reported in sebaceous gland tumors from patients with the Muir-Torre syndrome, the frequency of RER in human non-melanoma and melanoma skin cancers is not known. In this study, we investigated the importance of RER in human skin carcinogenesis. RER was identified in three of four actinic keratoses from a patient belonging to a kindred with documented Muir-Torre syndrome, which indicates that defective DNA replication may contribute to skin cancer development in such patients. Examination of a series of tumors from patients without Muir-Torre, including 137 skin cancers (47 basal cell carcinomas, 49 squamous cell carcinomas, and 41 primary malignant melanomas), 19 actinic keratoses, and 20 cases of Bowen's disease, using 10 or more microsatellite markers, identified repeat-sequence instability in less than 5% of the tumors studied. In six of the eight tumors, the sole change was an alteration 2 base pairs in length at a single locus. One patient with a squamous cell carcinoma showed changes at multiple loci suggesting defective mismatch repair. Although the low frequency of RER found in this study of a large series of human skin tumors suggests that this phenomenon is uncommon in patients with skin cancer, the identification of RER at multiple loci in two patients suggests that error-prone replication may be important in skin cancer development in some individuals.

A trichilemmal carcinoma arising from a proliferating trichilemmal cyst: the loss of the wild-type p53 is a critical event in malignant transformation.

The genetic events responsible for tumor progression may be defined by careful analysis of genetic changes in well-chosen tumors which contain distinct cell populations representing each stage of progression. Here we report a case of a trichilemmal carcinoma arising in the wall of a proliferating trichilemmal cyst (PTC). DNA was isolated from microdissected areas of the PTC and the carcinoma respectively, and PCR-based microsatellite loss of heterozygosity (LOH) analysis as well as p53 gene sequencing performed. A CGA to TGA nonsense mutation at codon 306 in exon 8 of the p53 gene was found in both samples. LOH analysis showed that the PTC retained chromosome arm 17p (where the p53 gene resides), whereas the carcinoma was associated with the loss of this allele. All the other loci examined were retained including 3p, 9q, 13q and 17q in both tumor parts. The results confirm a common clonal origin of the PTC and the trichilemmal carcinoma, and strongly suggest that the complete loss of the wild-type p53 is a critical event responsible for malignant transformation in this particular case.

In situ analysis of the degree of polymerization of bone cement by using FT-Raman spectroscopy.

A method has been developed which enables an in situ analysis of the degree of polymerization of bone cement. The concentration of monomeric double bond is monitored continuously during the entire curing process and hence the method can be used for quantitative studies of polymerization kinetics. In this study, Fourier Transform Raman (FTR) spectroscopy was utilized to investigate the degree of polymerization of a novel bone cement in situ, and the results are compared with the thermal profile obtained for polymerization.

Analysis of surface layers on bioactive glasses.

FT-Raman spectroscopy proves to be a powerful technique to study surface reactions on bioactive glasses and it eliminates the fluorescence of the organic phase of whole bone, thereby making it possible to compare the reaction layers formed on bioactive glasses with the mineral phase of bone. The spectrum of hydroxycarbonate apatite (HCA) developed on the bioactive glasses is closer to that of bone than synthetic hydroxyapatite (HA) and closely matches that of bone mineral obtained by deproteination of whole human femoral cortical bone.