Biodiversity in urban habitat patches

We examined the biodiversity of urban habitats in Birmingham (England) using a combination of field surveys of plants and carabid beetles, genetic studies of four species of butterflies, modelling the anthropochorous nature of the floral communities and spatially explicit modelling of selected mammal species. The aim of the project was to: (i) understand the ecological characteristics of the biota of cities model, (ii) examine the effects of habitat fragment size and connectivity upon the ecological diversity and individual species distributions, (iii) predict biodiversity in cities, and (iv) analyse the extent to which the flora and fauna utilise the 'urban greenways' both as wildlife corridors and as habitats in their own right. The results suggest that cities provide habitats for rich and diverse range of plants and animals, which occur sometimes in unlikely recombinant communities. The studies on carabids and butterflies illustrated the relative importance of habitat quality on individual sites as opposed to site location within the conurbation. This suggests that dispersal for most of our urban species is not a limiting factor in population persistence, although elements of the woodland carabid fauna did appear to have some geographical structuring. Theoretical models suggested that dormice and water voles may depend on linear habitats for dispersal. The models also indicated that other groups, such as small and medium sized mammals, may use corridors, although field-based research did not provide any evidence to suggest that plants or invertebrates use urban greenways for dispersal. This finding indicates the importance of identifying a target species or group of species for urban greenways intended as dispersal routeways rather than as habitat in their own right. Their importance for most groups is rather that greenways provide a chain of different habitats permeating the urban environment. We suggest that planners can have a positive impact on urban biodiversity by slowing the pace of redevelopment and by not hurrying to tidy up and redevelop brownfield sites.

Comparison of screw loosening, rotation, and deflection among three implant designs

A common problem associated with single tooth implant restorations is abutment screw loosening. Manufacturers of implants have attempted to overcome this problem by incorporating antirotational design characteristics into their systems. Micromovement and torque levels required to loosen abutment screws for straight and angled antirotational screw-retained abutment/implant combinations from three different manufacturers were examined in this in vitro investigation. A custom-built machine was used and each sample was subjected to compressive horizontal reciprocal movements over a 25-degree incline for a simulated 1-month period. Data were generated that showed movements of the crown/abutment complex during force application. The amount of torque necessary to loosen the abutment screws before and after testing was also recorded and compared for each system. The results indicated no significant differences (p < 0.05) among all the straight and angled abutments for the variables studied.

Equatorial Undercurrent Disappears During 1982-1983 El Nino

The equatorial undercurrent at 159 degrees W decayed during August 1982, partially reversed during September, and rapidly reappeared in January 1983. The virtual disappearance is consistent with the basin-wide adjustment of sea surface slope to the strong westerly winds in the western and central Pacific that caused the 1982-1983 El Niño event.

Parental stress, food parenting practices and child snack intake during the COVID-19 pandemic

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has caused unprecedented disruptions to the lives of families. This study aimed to investigate the impact of pandemic-associated stress on food parenting practices including interactions surrounding snacks, and child diet.

METHODS

Parents (N = 318) of 2-12-year old children completed a cross-sectional online survey assessing current COVID-19-specific stress, pre-COVID-19 stress, financial stress (e.g. food insecurity), food parenting practices, and child snack intake frequency. Structural Equation Modeling was used to model simultaneous paths of relationships and test direct and indirect effects.

RESULTS

Stress, including financial hardship, was higher compared with before the crisis. The majority of children had regular mealtimes and irregular snack times. Higher COVID-19-specific stress was associated with more non-nutritive use of food and snacks (e.g. emotional and instrumental feeding), but also more structure and positive interactions (e.g. eating with or engaging with child around mealtimes). Higher COVID-19-specific stress was also associated with greater child intake frequency of sweet and savory snacks, with some evidence for mediation by snack parenting practices.

CONCLUSION

Our findings indicate that stress associated with the COVID-19 pandemic may be linked to child snack intake with potential impacts on child obesity risk, and suggest several modifiable points of intervention within the family context.

A Lumped Parameter Approach to Vibration and Stress Analysis of Elastic Linkages

A method of kineto-elastodynamic analysis is developed employing lumped parameter models for simulating moving mechanism components considered as simply-supported beams subject to in-plane bending. Application of finite difference approximations to Euler’s beam theory leads to a system of nonlinear, ordinary differential equations of motion, and numerical solution of these equations is illustrated for specific examples. Variable as well as uniform cross-section members are analyzed for elastic vibration and stresses. By means of a general optimization procedure presented, nonuniform beam contours are obtained which provide a substantial stress reduction relative to the uniform case, without a corresponding increase in total mass.

Detection of the herpesviral hematopoietic necrosis disease agent (Cyprinid herpesvirus 2) in moribund and healthy goldfish: validation of a quantitative PCR diagnostic method

Cyprinid herpesvirus 2 (CyHV-2) is a pathogen of goldfish Carassius auratus auratus L. that causes herpesviral hematopoietic necrosis (HVHN) disease. The disease is associated with necrosis of hematopoietic tissues and anemia with high mortality. We have developed a real time 5'-nuclease PCR method (Taqman) that quantitatively detects CyHV-2 with a linear response over 8 logs of target concentration. The coefficient of variability on replicate samples tested on different days was 13% and the calculated sensitivity approached 1 target molecule per reaction. The assay does not cross-react with other similar fish herpesviruses, including CyHV-1 (carp pox) and CyHV-3 (koi herpesvirus), but reliably detects known CyHV-2 positive fish. The assay detects CyHV-2 not just in clinical cases of HVHN but also in apparently healthy 1 yr old goldfish fingerlings and even in 3 to 5 yr old broodfish.

The sequence of carnation etched ring virus DNA: comparison with cauliflower mosaic virus and retroviruses

Carnation etched ring virus (CERV) DNA comprises 7932 bp. CERV primer binding sites and overall genome organization are similar to those of the related cauliflower mosaic virus (CaMV). The six open reading frames of CERV showed amino acid homology (50-80%) with CaMV ORFs I-VI; no homologues of CaMV ORFs VII or VIII were found. CERV ORFs 1-5 interface each other with the sequence ATGA. The comparison of CERV ORF5 with CaMV ORFV highlighted regions which show homologies to retrovirus gag/pol protease, RNase H and DNA polymerase domains; the possibility that the DNA polymerase domain comprises two subdomains, operating off different templates, is discussed. Both CERV and CaMV ORFs I have sequence homology to tobacco mosaic virus P30 and plastocyanin.

lac repressor-lac operator interaction: NMR observations

We show here the changes in the NMR spectra of the Escherichia coli lac repressor when bound to isolated lac operator DNA. The observations focus on the aromatic residues--four tyrosines and a single histidine--in the amino-terminal DNA binding domain of the lac repressor. There is a good correlation between chemical shift changes seen by 19F NMR when compared with 1 H NMR of otherwise identical repressor--DNA complexes. The results suggest that the tyrosines do not intercalate in the DNA. The NMR spectral changes with similarly sized DNA fragments, not containing the lac operator DNA sequence, are different. Thus, the amino-terminal domain of the lac repressor is independently capable of discriminating between lac operator and nonspecific DNA sequences. There can be two amino-terminal fragments per operator in the specific complex.

A myeloproliferative disease in two infants associated with eosinophilia and chromosome t(1;5) translocation

Two children are described who presented at the age of 5 and 7 months with anaemia, a high white cell count with eosinophilia and thrombocytopenia. Both children had an identical balanced translocation t(1;5)(q23;q33) and no evidence of a constitutional abnormality. The response to treatment of one child was poor, the other remains well on therapy. This translocation has not been previously reported and is likely to represent a subclass of myeloproliferative disorder analogous to the monosomy 7 syndrome, although less common. The previous literature of acquired chromosome abnormalities involving chromosomes 1 and 5 is reviewed.

Application of transverse microradiography for measurement of mineral loss by acid erosion

This paper describes a novel application of transverse microradiography for the detection and quantification of mineral loss due to acid erosion in thin tooth sections. Sixty-four specimens were randomly divided into eight equal-sized groups and exposed to an orthophosphoric-acid-based erosive fluid (pH = 3) for 0, 0.25, 0.5, 1, 2, 5, 12, or 24 hrs. We made microdensitometric scans separately across both enamel and dentin to derive data for the total mineral loss and the minimum mineral content within the eroded area. We then analyzed specimens using a profilometer to determine (1) the area above a plot of penetration depth against distance and (2) the maximum depth of penetration. Correlation coefficients for comparisons between microradiographic and profilometric data for both enamel and dentin specimens varied between 0.87 and 0.96. Two-sample t tests demonstrated that the microradiographic technique could detect early erosion, i.e., discriminate between erosion times of less than 1 hr. It was concluded that this application of transverse microradiography was a useful and acceptable method for the measurement of early mineral loss in vitro, occurring as a result of acid erosion.

Optimum Mechanism Design Combining Kinematic and Dynamic-Force Considerations

A general computer-aided procedure is presented which combines the kinematic synthesis and dynamic design of four-bar mechanisms. This procedure utilizes nonlinear programming techniques, adjusting the arbitrary parameters in a kinematic synthesis to include performance criteria related to dynamic forces, as well as kinematics. In a particular example, optimum crank-rocker path generating mechanisms with prescribed timing are found based on objective functions related to shaking force, shaking moment, input torque fluctuation and bearing reactions. The optimization procedure results in a significant improvement in these dynamic characteristics.

Herpesviral haematopoietic necrosis virus (CyHV-2) infection: case studies from commercial goldfish farms

Herpesviral haematopoietic necrosis is a disease of goldfish, Carassius auratus, caused by Cyprinid herpesvirus-2 (CyHV-2) infection. Quantitative PCR was carried out on tissue homogenates from healthy goldfish fingerlings, broodfish, eggs and fry directly sampled from commercial farms, from moribund fish submitted to our laboratory for disease diagnosis, and on naturally-infected CyHV-2 carriers subjected to experimental stress treatments. Healthy fish from 14 of 18 farms were positive with copy numbers ranging from tens to 10(7) copies microg(-1) DNA extracted from infected fish. Of 118 pools of broodfish tested, 42 were positive. The CyHV-2 was detected in one lot of fry produced from disinfected eggs. Testing of moribund goldfish, in which we could not detect any other pathogens, produced 12 of 30 cases with 10(6)-10(8) copies of CyHV-2 microg(-1) DNA extracted. Subjecting healthy CyHV-2 carriers to cold shock (22-10 degrees C) but not heat, ammonia or high pH, increased viral copy numbers from mean copy number (+/-SE) of 7.3 +/- 11 to 394 +/- 55 microg(-1) DNA extracted after 24 h. CyHV-2 is widespread on commercial goldfish farms and outbreaks apparently occur when healthy carriers are subjected to a sharp temperature drop followed by holding at the permissive temperature for the disease.

Effect of digital image compression on screening for diabetic retinopathy

BACKGROUND/AIMS

Digital imaging is widely used for diabetic retinopathy screening. The storage and transmission of digital images can be facilitated by image compression. The authors aimed to assess the effect of image compression on the accuracy of grading diabetic retinopathy.

METHODS

Forty nine 35 mm transparencies (17 with no retinopathy, eight with background, five with preproliferative, and 19 with proliferative retinopathy) were digitised and subjected to JPEG compression by 90%, 80%, 70%, and 0%. The 196 images were randomised and graded on a portable computer. Two masked graders assessed the images for grade of retinopathy and image quality (0-10). The sensitivity and specificity of retinopathy grading were calculated with a weighted kappa for grading agreement between levels of compression.

RESULTS

The sensitivity of retinopathy grading was reduced by JPEG compression. At 90%, 80%, 70%, and 0% compression the sensitivities were 0.38, 0.50, 0.65, and 0.72, respectively; the specificity results were 1.00, 1.00, 0.83, and 0.84, respectively; and the weighted kappa scores were 0.60, 0.75, 0.77, and 0.84, respectively. The quality scores for 90%, 80%, 70%, 0% compression were 2.9 (SD 1.1, 95% CI; 2.7-3.2), 4.6 (SD 1.1, 95% CI; 3.0-5.6), 5.8 (SD1.5, 95% CI 5.0-6.6), 6.3 (SD1.4, 95% CI; 5.4-7.2) (p<0.01 for each intergroup comparison).

CONCLUSION

The results demonstrate significant loss of sensitivity to the features of diabetic retinopathy with JPEG compression; this was compounded by the thin film transistor (TFT) screen. The authors found the quality of uncompressed images on TFT screens too poor to give grading sensitivities which reach current guidelines for diabetic retinopathy screening.

Hospital-acquired infections in pediatric burn patients

To determine the epidemiologic characteristics of hospital-acquired infections (HAI) in pediatric burn patients, we retrospectively reviewed hospital charts of pediatric burn patients from two similar burn units. All patients less than 18 years of age admitted to the burn unit from January 1, 1980 to July 10, 1988, were enrolled. Charts were analyzed for age, sex, burn injury (type, depth, burn surface area), and hospital course (burn wound therapy, use of indwelling catheters or tubes, infectious complications, antibiotic use, cause of death if patient died). Statistical analysis was done using a logistic regression model. Of the 224 children admitted, 32 (14%) had 58 infections during their stay in the burn unit. There was no significant difference in age, sex, race, burn type or use of wound excision between patients with or without infection. Patients who acquired an infection were more likely to have sustained a > or = 20% full-thickness burn (14/32 vs 3/192 without infection), a smoke inhalation injury (10/32 vs 8/192), or have an indwelling device (29/32 vs 77/192). Thirteen (22%) of the 58 infections were burn wound infections due to Staphylococcus aureus or Pseudomonas aeruginosa, 12 (21%) were urinary tract infections due to Enterobacteriaceae, 11 (19%) were pneumonias caused by S aureus, Streptococcus pneumoniae or Pseudomonas sp, and 10 (17%) were bacteremias caused by S aureus or coagulase-negative staphylococci. The infection rate in pediatric patients hospitalized for burn injury in our study was significantly lower than the infection rate described for adult burn patients. As in adult patients, burn wound infections, pulmonary infections, and catheter-associated bacteremias are the most common infections in burned children. However, urinary tract infections are more frequent in the pediatric population. Risk factors (> or = 20% full-thickness burns, indwelling devices) and causative organisms are similar in both age groups.

Mechanical considerations for the implant tooth-supported fixed partial denture

The implant tooth-supported fixed partial denture presents a biomechanical design problem, because the implant is rigidly fixed within the alveolus, and the tooth is surrounded by a periodontal ligament that allows movement. Nonrigid fixed partial denture designs are advocated by some dentists as a method of compensating for this differential movement. Rigid fixed partial denture designs, however, are advocated by many clinicians. Studies have failed to show the advantage of one design over the other. This study developed an in vitro method for testing such prosthesis designs and measured movement of a natural tooth abutment during simulated function. The movement of the natural tooth abutment was not found to change substantially with the fixed partial denture designs tested.

An in vitro study of implant--tooth-supported connections using a robot test system

Many unsolved problems in dental implant research concern the interfacial stress distributions between the implant components, as well as between the implant surface and contacting bone. To obtain a mechanical understanding of how vertical and horizontal occlusal forces are distributed in this context, it is crucial to develop in vitro testing systems to measure the force transmission between dental implants and attached prostheses. A new approach to such testing, involving a robotic system, is described in this investigation. The system has been designed to produce simulated mandibular movements and occlusal contact forces so that various implant designs and procedures can be thoroughly tested and evaluated before animal testing or human clinical trials. Two commonly used fixed prosthesis designs used to connect an implant and a tooth, a rigid connection and a nonrigid connection, were fabricated and used for experimental verification. The displacement and force distributions generated during simulated chewing activities were measured in vitro. Force levels, potentially harmful to human bone surrounding the connected dental implant and tooth, were analyzed. These results are useful in the design of prostheses and connecting components that will reduce failures and limit stress transfer to the implant/bone interface.

Dense plasma heating by crossing relativistic electron beams

Here we investigate, using relativistic fluid theory and Vlasov-Maxwell simulations, the local heating of a dense plasma by two crossing electron beams. Heating occurs as an instability of the electron beams drives Langmuir waves, which couple nonlinearly into damped ion-acoustic waves. Simulations show a factor 2.8 increase in electron kinetic energy with a coupling efficiency of 18%. Our results support applications to the production of warm dense matter and as a driver for inertial fusion plasmas.

Pharmacokinetics of bretylium in man after intravenous administration

The pharmacokinetic profile of bretylium was studied in four normal male volunteers using a new sensitive EC-GC procedure for its quantitative in biological fluids. The plasma concentrations and urinary excretion rates following the constant i.v. infusion of a single 4 mg/kg dose of bretylium tosylate declined biexponentially and the data were fitted to a two-compartment model with a renal and a nonrenal route of elimination. The drug had a mean half-life (t1/2 beta) of 7.8 hr and apparent volume of distribution (Vd, beta) of 8.18 liters/kg. The renal clearance, which was 6 times that of the glomerular filtration rate, accounted for almost 84% of the total body clearance and correlated linearly with the subjects' creatinine clearance. The observed side effects of bretylium were mild and similar to those of other adrenergic blocking agents.

Does cigarette smoking increase plasma urotensin II concentrations?

OBJECTIVE

Human urotensin II (UII) acts on the urotensin (UT) receptor and is the most potent mammalian vasoconstrictor identified to date. The role of UII in human cardiovascular regulation remains unclear, and the results of plasma measurements have been conflicting, perhaps because different measurement techniques have been used. The effects of cigarette smoking on plasma UII concentrations are unknown. The primary aim of our study was to demonstrate whether cigarette smoking had any effect on plasma UII concentrations in otherwise healthy volunteers. Our secondary aim was to compare the results obtained from assaying simultaneously using both radioimmunoassay (RIA) and immunoluminometric assay (ILMA).

METHODS

Blood was taken from 20 healthy male non-smokers and 20 healthy male cigarette smokers. Plasma was separated and stored at -70 degrees C. Samples were batch analysed simultaneously for UII using RIA and ILMA.

RESULTS

Median (range) plasma UII concentrations were lower in non-smokers [1.67 (1.0-2.27) pg ml(-1)] compared to smokers [2.62 (1.87-3.46) pg ml(-1)] (P = 0.03) measured using RIA. Those who had smoked a cigarette in the 10 min before sampling had greater concentrations of UII [3.10 (1.87-4.60) pg ml(-1)] compared to controls (P = 0.01). Plasma UII concentrations determined by ILMA were consistently low with no differences between groups.

CONCLUSION

The data obtained by RIA show that smoking may increase plasma concentrations of UII with a more pronounced increase when a cigarette has been smoked recently. There was a complete lack of correlation between RIA and ILMA for the whole data set, which suggests that some of the variability in plasma UII reported in the literature may result from differences between assays.

A very modest proposal for 1990s C/L psychiatry

The prediction that consultation-liaison psychiatry would play an integral role in the management of all medical/surgical patients in large hospitals has not come to pass. The primary reason is that no adequate funding mechanism has ever been found to support such a large endeavor. The economic climate as we enter the 1990s makes such funding even less likely. The authors suggest that C/L psychiatry accept a lesser role, largely confined to teaching hospitals. That role, which has been successful at a large public teaching hospital for nearly 10 years, encompasses serving as a primary psychiatric teaching site for medical students, a primary teaching site for psychiatry residents and other postgraduate physicians rotating through psychiatry, a source of innovative dispositions for medically ill psychiatric patients, and a source of opportunity for interdisciplinary research.