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PubMed2006

Hardness and carbonate effects on the reactivity of zero-valent iron for Cr(VI) removal.

Zero-valent iron (Fe0) was used to remove hexavalent chromium, Cr(VI), in groundwater via a coupled reduction-oxidation reaction. Nine columns were set up under various groundwater geochemistry to investigate the effects of hardness and carbonate on Cr(VI) removal. The Cr(VI) removal capacity of Fe0 was found to be about 4 mgCr/g Fe0 in the control column (i.e., column 1). A slight decrease in the Cr(VI) removal capacity was found in the presence of calcium hardness. However, there was a 17% drop in the Cr(VI) removal capacity when magnesium hardness was present at low to moderately hard level. Results also revealed that carbonate changed the morphology of the Fe0 by formation of pale green precipitates on the iron filings. Furthermore, there was a 33% decrease in the Cr(VI) removal capacity of Fe0 when both carbonate and hardness ions were present. In general, the presence of hardness ions and carbonate in groundwater have great impact on the Fe0 by formation of passivated precipitates, such as CaCO3, on the Fe0 surface resulting in a diminished lifespan of the Fe0 by blocking electron transfer.

Calcium Carbonate↗
PubMed1998

Localization of atrial natriuretic peptide receptors in the rat tongue and hard palate.

Atrial natriuretic peptide (ANP) receptors were characterized in rat oral mucosa using quantitative in vitro autoradiography and activation of particulate guanylyl cyclase (GC) by natriuretic peptides. Competition-binding analysis performed by quantitative in vitro autoradiography demonstrated specific [125I]rANP(1-28) binding sites in the tongue and hard palate. The precise location of this binding was revealed on the basal and parabasal cells of the epithelia by microautoradiography. The dissociation constant (Kd) and maximal binding capacity (Bmax) of these sites were 3.34+/-1.35 nM and 2.71+/-2.21 fmol/mm2 on the epithelium of the tongue, and 4.09+/-1.52 nM and 3.45+/-3.01 fmol/mm2 on the epithelium of the hard palate, respectively. Receptor subtypes were characterized by competition with des [Gln18, Ser19, Gly20, Leu21, Gly22] ANP(4-23) (C-ANP), a specific ligand for the clearance receptor (NPR-C). These binding sites were displaced by C-ANP with inhibition constant (Ki) of 8.96+/-3.18 nM and Bmax of 2.89+/-2.45 fmol/mm2 on the epithelium of the tongue, and Ki of 9.12+/-2.71 nM and Bmax of 3.08+/-2.94 fmol/mm2 on the epithelium of the hard palate, respectively. Production of cyclic GMP by particulate GC in the epithelial membranes of the tongue and hard palate was stimulated by rANP(1-28), porcine brain natriuretic peptide (BNP)(1-26), and C-type natriuretic peptide (CNP)(1-22) in a dose-dependent manner. These results indicate that ANP-binding sites in the epithelium of the tongue and hard palate are mainly clearance receptors (NPR-C) but biological receptors (NPR-A and/or NPR-B) with GC activity are also present, and suggest that ANP may have a role in the proliferation of the oral epithelial cells, especially in the tongue and hard palate.

Analysis of Variance↗
PubMed1997

Effect of danaparoid sodium on hard exudates in diabetic retinopathy.

BACKGROUND: In diabetes mellitus, both retinopathy and nephropathy represent specific microvascular disease with increased capillary permeability resulting in hard exudates, foveal oedema, and albuminuria. The decrease of heparan-sulphate content of the glomerular-basement membrane is quantitatively related to the rate of proteinuria in nephropathy associated with insulin-dependent diabetes mellitus (IDDM). Several short-term studies in patients with IDDM and non-IDDM have shown that a reduction of microalbuminuria and macroalbuminuria can be achieved with the supplementation of glycosaminoglycans. After completion of a study on the effect of danaparoid sodium on albumin excretion in patients with IDDM and macroalbuminuria, we hypothesised that treatment with danaparoid sodium also influenced retinal leakage in the patients in that trial. METHODS: In this retrospective study nine patients with nephropathy received 750 anti-Xa units danaparoid sodium once a day for 6 weeks in a placebo-controlled double-blind cross-over study. Fundus photographs, done at baseline and at the end of the study, were semiquantitatively scored for the severity of hard exudates. FINDINGS: At baseline 14 eyes had grade 1 to 5 severity of hard exudates and four eyes were without hard exudates (grade 0). There was no progression in the latter four eyes. In ten eyes an improvement was observed: four patients showed a favourable response to treatment in both eyes and two patients showed improvement in one eye. We found improvement of hard exudates after 6 weeks of treatment with danaparoid sodium. INTERPRETATION: Our uncontrolled observation indicates that the supplementation of danaparoid sodium influences both the permeability of retinal vessels as well as of glomerular vessels. Danaparoid-sodium therapy as a systemic adjuvant is worth considering for treatment strategies for foveal oedema and hard exudates in diabetic maculopathy.

Adult↗
PubMed1992

Blepharoptosis induced by prolonged hard contact lens wear.

PURPOSE: The authors attempt to establish a relation between hard contact lens wear and upper eyelid ptosis. METHODS: This study consists of two parts. In the first part, the authors compare the unilateral or bilateral ptosis that developed during hard contact lens wear in 17 patients with the involutional ptosis that developed in another group of 73 patients. In the second part, the authors compare both upper and lower eyelid position in 46 patients who had been wearing hard contact lenses for at least 10 years with the position of 50 matched controls who had never worn contact lenses. RESULTS: The ptosis that had developed in the 17 patients who wore hard contact lenses was clinically similar to that caused by involutional levator disinsertion. The second part of the study shows that the prolonged wearers of hard contact lenses had upper eyelids that were lower by approximately 0.5 mm when compared with control subjects. This difference is statistically significant. According to standard criteria, there were at least 10 ptotic eyelids in the contact lens group versus 1 in the control group. CONCLUSION: The study findings suggest that prolonged hard contact lens wear may induce a lower position of the upper eyelid and eventually lead to ptosis through levator disinsertion.

Adolescent↗
PubMed1999

Assessing the performance of NHS hospital trusts: the role of 'hard' and 'soft' information.

Formal performance measurement systems have become a prominent feature throughout most of the public sector. The NHS is no exception and the government is developing and expanding on existing performance data to produce a new national framework which is to be at the heart of the 'performance-led' NHS. The success of formal performance measurement systems depends in part on the degree to which they can capture adequately relevant information within a quantitative framework. In this paper, we explore the use of formal, quantitative 'hard' information and informal, subjective 'soft' information in the assessment of the performance of NHS hospital Trusts by external organisations. Our empirical work is summarised into 3 main themes: (i) the use of 'soft' information as a complement to 'hard' information; (ii) the use of 'soft' information as a substitute for 'hard' information; and (iii) the use of 'hard' information as a safety net in the assessment of performance. We argue that 'soft' information plays a valuable role in the assessment of performance of NHS Trusts and note that this is also reflected in current practice in the private sector. We argue that one of the main functions of 'hard' information in performance assessment is to act as a safety net in order to identify laggards by highlighting poor performance. Rarely is it used as a means to encourage good performance or to identify best practice. Whilst the safety net function may indeed be useful, if the new national performance framework is to achieve its aim of promoting good performance, the limitations of formal systems will have to be taken into account. We argue that the advantages of 'soft' information in the NHS should be acknowledged, rather than trying to force it into a formal framework where the benefits may be nullified. However, we also warn against excessive reliance on 'soft' information and suggest that a balanced system which allows both 'hard' and 'soft' information to flourish is the optimal solution to performance assessment in the NHS.

Efficiency, Organizational↗
PubMed2002

Hydration entropy change from the hard sphere model.

The gas to liquid transfer entropy change for a pure non-polar liquid can be calculated quite accurately using a hard sphere model that obeys the Carnahan-Starling equation of state. The same procedure fails to produce a reasonable value for hydrogen bonding liquids such as water, methanol and ethanol. However, the size of the molecules increases when the hydrogen bonds are turned off to produce the hard sphere system and the volume packing density rises. We show here that the hard sphere system that has this increased packing density reproduces the experimental transfer entropy values rather well. The gas to water transfer entropy values for small non-polar hydrocarbons is also not reproduced by a hard sphere model, whether one uses the normal (2.8 A diameter) or the increased (3.2 A) size for water. At least part of the reason that the hard sphere model with 2.8 A size water produces too small entropy change is that the size of water is too small for a system without hydrogen bonds. The reason that the 3.2 A model also produces too small entropy values is that this is an overly crowded system and that the free volume introduced in the system by the addition of a solute molecule produces too much of a relief to this crowding. A hard sphere model, in which the free volume increase is limited by requiring that the average surface-to-surface distance between the solute and water molecules is the same as that between the increased-size water molecules, does approximately reproduce the experimental hydration entropy values.

Entropy↗
PubMed2001

A double exposed portal image comparison between electronic portal imaging hard copies and port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center.

PURPOSE: At the William Buckland Radiotherapy Center (WBRC), field-only electronic portal image (EPI) hard copies are used for radiation treatment field verification for whole brain, breast, chest, spine, and large pelvic fields, as determined by a previous study. A subsequent research project, addressing the quality of double exposed EPI hard copies for sites where field only EPI was not considered adequate to determine field placement, has been undertaken. The double exposed EPI hard copies were compared to conventional double exposed port films for small pelvic, partial brain, and head and neck fields and for a miscellaneous group. METHODS AND MATERIALS: All double exposed EPIs were captured during routine clinical procedures using liquid ion chamber cassettes. EPI hard copies were generated using a Visiplex multi-format camera. In sites where port film remained the preferred verification format, the port films were generated as per department protocol. In addition EPIs were collected specifically for this project. Four radiation oncologists performed the evaluation of EPI and port film images independently with a questionnaire completed at each stage of the evaluation process to assess the following: Adequacy of information in the image to assess field placement. Adequacy of information for determining field placement correction. Clinician's preferred choice of imaging for field placement assessment RESULTS: The results indicate that double exposed EPI hard copies generally do containsufficient information to permit evaluation of field placement and can replace conventionaldouble exposed port films in a significant number of sites. These include the following:pelvis fields < 12 X 12 cm, partial brain fields, and a miscellaneous group. However forradical head and neck fields, the preferred verification image format remained port film dueto the image hard copy size and improved contrast for this media. Thus in this departmenthard copy EPI is the preferred modality of field verification for all sites except radical headand neck treatments. This should result in an increase in efficiency of workloadmanagement and patient care.

Head and Neck Neoplasms↗
PubMed1999

A comparison of field-only electronic portal imaging hard copies with double exposure port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center.

PURPOSE: To determine in which treatment sites field-only hard copy electronic portal images (EPI) captured during a treatment exposure could replace traditional double exposed port films in a busy radiation oncology department. METHODS AND MATERIALS: The three linear accelerators in the William Buckland Radiotherapy Centre (WBRC) at the Alfred Hospital in Melbourne are each equipped with an electronic portal imaging device (EPID). These devices can be used daily on all patients where the treatment fields are within the size constraint of the cassette, for example, less than 25 x 25 cm. Port films using radiographic film in hard cassettes were previously considered the standard method of field placement verification. After the radiation therapists were trained in all program aspects of capturing, enhancing, and producing hard copies of EPIs, a study was developed to evaluate the possibility of replacing port films with EPI hard copies within the established departmental procedures. Comparison of EPI hard copy with the simulator film and the port film of the same field was carried out by the radiation oncologist specialists. Seventy-eight comparison sets were generated and grouped into seven anatomical regions for evaluation by the radiation oncologist specialist responsible for each particular region. The outcome decision was the preferred imaging option. Where no preference was stated, EPI became the modality of choice, as it increased the efficiency of work practice. RESULTS: The results indicate that field-only EPI can be considered to be at least as clinically useful for treatment verification in the following sites: breast, chest, hip, spine, and large pelvic fields. Port films using a standard, double exposure technique were considered necessary for partial brain fields, small pelvis fields, extremities, and radical head and neck fields. CONCLUSION: The quality of field-only images captured using an EPID has been favorably assessed to be equivalent to, or an improvement on, the traditional double exposed port films for some treatment areas. Departmental policy has been altered to incorporate this new imaging modality as a practical alternative to port films, resulting in a direct benefit in terms of resource management and patient care. Continuing research is currently evaluating open area exposed EPI hard copies as a potential alternative to port films.

Feasibility Studies↗
PubMed2005

Development of SNP assays for genotyping the puroindoline b gene for grain hardness in wheat using pyrosequencing.

Grain hardness is one of the most important quality characteristics of cultivated bread wheat (Triticum aestivum L.) and has been reported to result from either a failure to express puroindoline a (Pina) or single-nucleotide mutations in puroindoline b (Pinb). Up to now, seven alleles from Pinb-D1a to Pinb-D1g were identified in bread wheat. Compared to the DNA coding region of Pinb-D1a (allele for softness), six single-nucleotide polymorphisms (SNPs) were detected in six alleles for Pinb-D1. In this study, we used pyrosequencing technology to develop two SNP assays for identification of the seven Pinb alleles and characterized SNP variations in the Pinb of 493 European wheat varieties. Of the three hardness alleles Pinb-D1b, Pinb-D1c, and Pinb-D1d detected in this study, Pinb-D1b was the most predominant hardness allele in European hard wheats. The hardness genotypes of partial German wheat varieties available confirmed the reliability and validation of the SNP assays developed for the Pinb locus. Therefore, pyrosequencing technology offers an efficient, precise, and reliable concept for high-throughout genotyping to assist selection of grain hardness genes in wheat quality breeding programs.

Alleles↗
PubMed2005

Geometrical characteristics of the enlarged fused hard sphere models of simple molecules.

The enlarged fused hard sphere model represents a compromise between fused hard sphere- and hard convex body models of repulsive interactions of nonspherical molecules. Geometric functionals of the enlarged fused hard sphere models, i.e., the hard body volume, surface area, and "mean radius" for 25 molecules of the linear and approximately planar shapes (cycloalkanes and aromatic compounds), neopentane and cyclohexane were determined from the bond lengths and bond angles and expressed in the dimensionless form. The hard sphere diameters, first approximated by the values found from the correlation of the second virial coefficients, were then adjusted to heats of vaporization of the studied compounds. Parameters of nonsphericity and molar volumes, evaluated from these characteristics, are compared with parameters of modern semiempirical equations of state (BACK, BACKONE, SAFT). The calculated geometric quantities for a series of compounds make it possible to improve methods of determining the characteristic parameters of the modern semiempirical equations of state, as well as those from the perturbation approaches.

Journal Article↗
PubMed2001

Water hardness and sodium trends in Texas aquifers.

Median hardness and sodium levels in groundwater were calculated for 244 Texas counties from measurements at 7728 water wells. The data were mapped and analyzed with a geographic information system (GIS). County median hardness levels varied widely, from 4-2304 mg L-1. More than 60% of the counties had hardness medians above 180 mg L-1. County medium sodium concentrations ranged from 6-1170 mg L-1, with more than 90% of those values exceeding 20 mg L-1. There was a significant positive correlation between hardness and sodium concentrations in six of Texas' nine major aquifers. A significant negative correlation between hardness and sodium was observed in two aquifers. Several factors control hardness and sodium variations in Texas aquifers including rock/sediment composition, groundwater chemical evolution, and seepage from nearby formations. Probable human controls include agricultural return flow and pumping-induced saltwater intrusion.

Agriculture↗
PubMed1997

Post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin.

This study examined the post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin using a digital microhardness tester. Change in hardness of these materials over a period of 6 months was compared to that of conventional glass ionomer cements and a composite resin. With the exception of the composite resin, all materials showed a significant increase in hardness over 24 h after their initial set. Dual-cure resin-modified glass ionomer cements showed decreased hardness with increased storage time in saline at 37 degrees C. Results suggest that the addition of resins to glass ionomer cements does not improve initial hardness and does not negate the acid-base reaction of conventional cements. Resin addition may, however, lead to increased water sorption and decreased hardness.

Journal Article↗
PubMed2005

Prediction of collective diffusion coefficient of bovine serum albumin in aqueous electrolyte solution with hard-core two-Yukawa potential.

A new method to predict concentration dependence of collective diffusion coefficient of bovine serum albumin (BSA) in aqueous electrolyte solution is developed based on the generalized Stokes-Einstein equation which relates the diffusion coefficient to the osmotic pressure. The concentration dependence of osmotic pressure is evaluated using the solution of the mean spherical approximation for the two-Yukawa model fluid. The two empirical correlations of sedimentation coefficient are tested in this work. One is for a disordered suspension of hard spheres, and another is for an ordered suspension of hard spheres. The concentration dependence of the collective diffusion coefficient of BSA under different solution conditions, such as pH and ionic strength is predicted. From the comparison between the predicted and experimental values we found that the sedimentation coefficient for the disordered suspension of hard spheres is more suitable for the prediction of the collective diffusion coefficients of charged BSA in aqueous electrolyte solution. The theoretical predictions from the hard-core two-Yukawa model coupled with the sedimentation coefficient for a suspension of hard spheres are in good agreement with available experimental data, while the hard sphere model is unable to describe the behavior of diffusion due to its neglect of the double-layer repulsive charge-charge interaction between BSA molecules.

Algorithms↗
PubMed2001

Use of electron beam tomography data to develop models for prediction of hard coronary events.

BACKGROUND: Prediction of hard cardiac events (myocardial infarction and coronary death) remains difficult in spite of the identification of several relevant risk factors for the development of coronary artery disease (CAD). New indicators of risk might add to our predictive ability. We used measures of coronary artery calcification (CAC) found by electron beam tomography (EBT) imaging to develop prediction models for hard cardiac events alone and in association with traditional risk factors for CAD. METHODS: Two groups of patients were studied: group A, 676 asymptomatic patients (mean age 52 years, 51% men) prospectively followed up for 32 +/- 7 months after being referred by primary care physicians for a screening EBT, and group B, 10,122 asymptomatic patients screened by EBT at one center and used as controls for calculation of calcium score nomograms. RESULTS: The occurrence of hard events in group A patients was related to traditional risk factors for CAD, presence of CAC (score >0), Ln (1 + absolute calcium score [CS]), and age- and sex-specific CS percentiles (CS%). Univariate analyses showed that age, smoking, diabetes mellitus, presence of CAC, Ln (1 + absolute CS), and CS% were predictive of hard events (all P <.05). Multiple logistic regression analyses demonstrated that CS% was the only significant predictor of events and provided incremental prognostic value when added to traditional risk factors for CAD (chi-square, P <.001). In a comparison of receiver-operator characteristic curves for prediction of hard events, the area under the curve for CS% plus conventional risk factors and age was significantly larger than that obtained by use of traditional risk factors and age separately as predictors (0.84 vs 0.71, respectively, P <.001). Furthermore, the area under the curve of CS% alone was significantly larger than that of traditional risk factors and age combined (0.82 vs 0.71, P =.028). CONCLUSIONS: Patients are usually selected for EBT screening on the basis of the presence of conventional risk factors for CAD. However, an age- and sex-specific calcium score provides the best predictive model for the occurrence of hard coronary events and adds incremental prognostic information to conventional risk factors for CAD.

Aged↗
PubMed1996

Relationship between water hardness and coronary mortality in Taiwan.

A number of studies carried out in other countries have shown the existence of negative correlations between coronary mortality and the hardness of water supplies. Data on water hardness throughout Taiwan have been collected from Taiwan Water Supply Corporation (TWSC) to examine the ecological correlation between deaths from coronary disease (1981-1990) and total hardness in drinking water. Analysis demonstrates a significant negative association between drinking water hardness and coronary mortality. After adjustment for the urbanization index, coronary mortality in municipalities with soft water was estimated to be 9.6% higher than that in municipalities with hard water. The weighted multivariate-adjusted regression coefficient indicated a decrease of 0.053 in standardized mortality ratios (SMRs) for every 100 mg/L increase in total hardness in drinking water after allowing for the urbanization condition.

Calcium Carbonate↗
PubMed2003

Induction of hard keratin expression in non-nail-matrical keratinocytes by nail-matrical fibroblasts through epithelial-mesenchymal interactions.

Epithelium in the nail matrix is different from that at other body sites, in terms of clinical and histological appearance. Hard keratins are exclusively expressed in the nail matrix and bed and the hair apparatus, and hard keratin is considered a differentiation marker of these sites. Whether the expression of hard keratin in non-nail-matrical keratinocytes could be induced by nail-matrical fibroblasts was examined. Skin equivalents were constructed in three ways; ventral keratinocytes (from the ventral side of the digit) were cocultured with ventral fibroblasts (group A), ventral keratinocytes were cocultured with nail-matrical fibroblasts (group B), and nail-matrical keratinocytes were cocultured with ventral fibroblasts (group C). Immunohistochemical examinations with anti-hard keratin antibody (HKN-7) revealed hard keratin expression in groups B and C. HKN-7-positive cells were distributed continuously in the entire epithelial strata or in the suprabasal layer in group B, whereas HKN-7-positive cells were distributed spottily in group C. This study indicates extrinsic hard keratin induction in non-nail-matrical keratinocytes by nail-matrical fibroblasts and suggests that non-nail-matrical epidermal grafts may be effective in the treatment of deepithelized nail injuries. In addition, it is possible that lost nails could be reconstructed with grafts of "tissue-engineered" nail equivalent.

Antibodies, Monoclonal↗
PubMed2004

Effect of hard-drug use on CD4 cell percentage, HIV RNA level, and progression to AIDS-defining class C events among HIV-infected women.

In vitro and animal studies suggest that cocaine and heroin increase HIV replication and suppress immune function, whereas epidemiologic studies are inconclusive regarding their effect on HIV infection progression. The authors prospectively examined the association between illicit-drug use and 4 outcome measures (CD4 cell percentage, HIV RNA level, survival to class C diagnosis of HIV infection, and death) in a national cohort of HIV-infected women. Women enrolled between 1989 and 1995 were followed for 5 years and repeatedly interviewed about illicit ("hard")--drug use. Up to 3 periodic urine screens validated self-reported use. Outcomes were compared between hard-drug users (women using cocaine, heroin, methadone, or injecting drugs) and nonusers, adjusting for age, antiretroviral therapy, number of pregnancies, smoking, and baseline CD4 cell percentage. Of 1148 women, 40% reported baseline hard-drug use during pregnancy. In multivariate analyses, hard-drug use was not associated with change in CD4 cell percentage (P = 0.84), HIV RNA level (P = 0.48), or all-cause mortality (relative hazard = 1.10; 95% confidence interval, 0.61-1.98). Hard-drug users did, however, exhibit a higher risk of developing class C diagnoses (relative hazard = 1.65; 95% confidence interval, 1.00-2.72), especially herpes, pulmonary tuberculosis, and recurrent pneumonia. Hard-drug-using women may have a higher risk for nonfatal opportunistic infections.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Weighted density functional theory of spherically inhomogeneous hard spheres.

The weighted density functional theory of hard sphere fluids proposed by Tarazona is applied to spherically inhomogeneous hard sphere fluids. The density profile of a hard sphere fluid around a hard sphere particle with structureless hard wall and varying radii is obtained. Our results are compared with previously obtained computer simulation with good agreement. We also calculate the density profile of a hard sphere fluid confined to spherical pores. We compare these results with those obtained by Calleja et al., in which both theory and computer simulation are used. In this case the results are also in agreement.

Journal Article↗