Structural signature of sporadic Creutzfeldt-Jakob disease.

BACKGROUND AND PURPOSE: Sporadic Creutzfeldt-Jakob disease (sCJD) is a rapidly progressive neurodegenerative disease caused by an abnormal isoform of the human prion protein. Structural magnetic resonance imaging in patients with pathologically confirmed sCJD was compared with cognitively normal individuals to identify a cortical thickness signature of sCJD. METHODS: This retrospective cross-sectional study compared patients with autopsy-confirmed sCJD with dementia (n = 11) with age- and sex-matched cognitively normal individuals (n = 22). We identified regions of interest (ROIs) in which cortical thickness was most affected by sCJD. Within patients with sCJD, the relationship between ROI cortical thickness and clinical measures (disease duration, cerebrospinal fluid tau and diffusion-weighted imaging abnormalities) was evaluated. RESULTS: Compared with cognitively normal individuals, patients with sCJD had significantly reduced cortical thickness in multiple ROIs, including the fusiform gyrus, precentral gyrus, precuneus and superior temporal gyrus bilaterally; the caudal middle frontal gyrus, superior frontal gyrus, postcentral gyrus, inferior temporal gyrus and transverse temporal gyrus in the left hemisphere; and the superior parietal lobule in the right hemisphere. Only one patient with sCJD had co-pathology consistent with Alzheimer's disease. Reduced cortical thickness did not correlate with disease duration, presence of diffusion restriction or elevated cerebrospinal fluid tau. CONCLUSION: Cortical signature changes in sCJD may reflect brain changes not captured by standard clinical measures. This information may be used with clinical measures to inform the progression of sCJD and patterns of prion protein spread throughout the brain. These results may have implications for prediction of symptomatic progression and plausibly for development of therapeutic strategies.

The relationship between compost bedded pack performance, management, and bacterial counts.

The objective of this study was to assess the relationships among temperature, moisture, carbon-to-nitrogen (C:N) ratio, space per cow, and bacterial counts from bedding material collected from compost bedded pack (CBP) barns. A field survey of 42 routinely aerated CBP barns was conducted in Kentucky between October 2010 and March 2011. Two bedding material samples of 1,064.7 cm(3) each were collected during a single site visit from 9 evenly distributed locations throughout each barn and thoroughly mixed to create a composite sample representative of the entire CBP. Bacterial counts were determined for coliforms, Escherichia coli, streptococci, staphylococci, and Bacillus spp. University of Kentucky Regulatory Services (Lexington) laboratory personnel performed nutrient analyses to determine moisture, carbon, and nitrogen contents. Surface and 10.2-cm pack depth temperatures were collected for each of the 9 evenly distributed locations and the mean calculated to produce a composite temperature. Space per cow was calculated as the total CBP area divided by number of cows housed on the CBP. The GLM procedure of SAS (SAS Institute Inc., Cary, NC) generated models to describe factors affecting bacterial counts. Bacterial counts were 6.3 ± 0.6, 6.0 ± 0.6, 7.2 ± 0.7, 7.9 ± 0.5, and 7.6 ± 0.5 log 10 cfu/g of dry matter for coliform, Escherichia coli, streptococci, staphylococci, and Bacillus spp., respectively. Composite temperature, CBP moisture, C:N ratio, and space per cow had no effect on coliform counts. Escherichia coli reached a peak concentration when the C:N ratio was between 30:1 and 35:1. Staphylococci counts increased as ambient temperature increased. Streptococci counts decreased with increased space per cow and composite temperature and increased with increasing ambient temperature and moisture. Streptococci counts peaked at a C:N ratio ranging from 16:1 to 18:1. Bacillus spp. counts were reduced with increasing moisture, C:N ratio, and ambient temperature. Mastitis-causing bacteria thrive in similar conditions to that of composting bacteria and microbes, making elimination of these at higher temperatures (55 to 65°C) difficult in an active composting environment. Producers must use recommended milking procedures and other preventative practices to maintain low somatic cell count in herds with a CBP barn.

Compost bedded pack dairy barn management, performance, and producer satisfaction.

The objective of the research was to characterize herd performance, producer satisfaction and recommendations, and management practices used by compost bedded pack (CBP) managers in Kentucky (42 farms and 47 CBP facilities). Farms were visited between October 2010 and March 2011. A random selection of cows housed solely in the CBP were scored for locomotion and hygiene. Changes in monthly Dairy Herd Improvement Association performance records, including milk production, SCC, reproductive performance, and daily bulk-tank somatic cell count after moving into the CBP were analyzed using the MIXED procedure of SAS (SAS 9.3; SAS Institute Inc., Cary, NC). The GLM procedure of SAS (SAS 9.3) was used to develop models to describe CBP moisture, CBP temperature at 20.3 cm, and mean herd hygiene. Producers provided 9.0 ± 2.2 m2 of pack space per cow (n = 44). Barns constructed with an attached feed alley cost $1,051 ± 407 per cow (n = 40). Barns constructed without an attached feed alley cost $493 ± 196 per cow (n = 13). Kiln-dried shavings required 0.05 ± 0.04 m3 of bedding per cow per day (n = 15). Green shavings required 0.07 ± 0.06 m3 of bedding per cow per day (n = 12). The most-frequently cited benefits of the CBP included cow comfort (n = 28), cow cleanliness (n = 14), and the low-maintenance nature of the system (n = 10). Increased stirring frequency, stirring depth, and ambient temperature increased pack temperature, measured at 20.3 cm below the CBP surface. Increased stirring depth, pasture-adjusted space per cow, and drying rate decreased CBP moisture. Mean herd locomotion and hygiene scores were 1.5 ± 0.3 (n = 34) and 2.2 ± 0.4 (n = 34), respectively. Increased 20.3-cm depth CBP temperature and ambient temperatures improved mean herd hygiene. Bulk-tank somatic cell count decreased from the year before to the year after moving into the CBP barn (323,692 ± 7,301 vs. 252,859 ± 7,112 cells/mL, respectively) for farms using the CBP barn as the primary housing facility (n = 9). Daily milk production, collected from monthly Dairy Herd Improvement Association tests, increased from before moving into the CBP barn to the second year after (29.3 ± 0.3 vs. 30.7 ± 0.3 kg, respectively) for farms using the CBP barn as the primary housing facility (n = 8). Calving interval decreased from the year before to the second year after (14.3 ± 0.1 vs. 13.7 ± 0.1 mo) moving into the CBP barn for farms using the CBP as primary housing (n = 8).

Axonal damage and astrocytosis are biological correlates of grey matter network integrity loss: a cohort study in autosomal dominant Alzheimer disease.

Brain development and maturation leads to grey matter networks that can be measured using magnetic resonance imaging. Network integrity is an indicator of information processing capacity which declines in neurodegenerative disorders such as Alzheimer disease (AD). The biological mechanisms causing this loss of network integrity remain unknown. Cerebrospinal fluid (CSF) protein biomarkers are available for studying diverse pathological mechanisms in humans and can provide insight into decline. We investigated the relationships between 10 CSF proteins and network integrity in mutation carriers (N=219) and noncarriers (N=136) of the Dominantly Inherited Alzheimer Network Observational study. Abnormalities in Aß, Tau, synaptic (SNAP-25, neurogranin) and neuronal calcium-sensor protein (VILIP-1) preceded grey matter network disruptions by several years, while inflammation related (YKL-40) and axonal injury (NfL) abnormalities co-occurred and correlated with network integrity. This suggests that axonal loss and inflammation play a role in structural grey matter network changes. Key points: Abnormal levels of fluid markers for neuronal damage and inflammatory processes in CSF are associated with grey matter network disruptions.The strongest association was with NfL, suggesting that axonal loss may contribute to disrupted network organization as observed in AD.Tracking biomarker trajectories over the disease course, changes in CSF biomarkers generally precede changes in brain networks by several years.

Using Statistical Shape and Appearance Modelling to characterise the 3D shape and material properties of human lumbar vertebrae: A proof of concept study.

Patient variation affects the outcomes of a range of spinal interventions, from disc replacement to vertebral fixation and vertebroplasty. Statistical Shape and Appearance Modelling (SSAM) can be used to describe anatomical variation and pathological differences within the population. To better understand how bone density and shape variation affect load transfer with respect to surgical treatments, Finite Element (FE) models can be generated from a SSAM. The aim for this study is to understand whether geometric and density variation as well as multiple vertebral levels can be incorporated into a single SSAM and whether this can be used to investigate the relationships between, and effects of, the various modes of variation. FE models of 14 human lumbar vertebrae that had been µCT imaged and validated through experimental testing were used as input specimens for a SSAM. The validity of the SSAM was evaluated by using principal component analysis to identify the primary modes of geometric and bone density variation and comparing to those in the input set. FE models were generated from the SSAM to examine the response to loading. The mean error between the input set and generated models for volume, mean density and FE compressive stiffness were 10%, 3% and 10% respectively. Principal Component (PC) 1 captured the majority of the bone density variation. The remaining PCs described specific geometric variation. The FE models generated from the SSAM showed the variations in vertebral stiffness as a result of complex relationships between bone density and shape. The SSAM created has limited data for its input set, however, it acts as a proof of concept for the novel combination of material and shape variation into a single shape model. This approach and the tools developed can be applied to wider patient groups and treatment scenarios to improve patient stratification and to optimise treatments.

Association of Maternal Vitamin D Deficiency with Early Childhood Caries.

Alaska Native (AN) children experience one of the highest reported rates of severe early childhood caries (S-ECC). Serum vitamin D concentrations in AN childbearing women in the Yukon Kuskokwim Delta (YKD) region have decreased since the 1960s to currently low levels, related to a decrease in traditional marine diet. Recent studies suggest an association between prenatal vitamin D (25(OH)D) concentrations in mothers and S-ECC in their infants. We used independent t tests to analyze the influence of prenatal 25(OH)D levels in YKD AN mothers on S-ECC in their children using data collected in the Maternal Organics Monitoring Study (MOMS). Maternal 25(OH)D levels were assessed at prenatal visits and in cord blood. We queried electronic dental records to assess early childhood caries (ECC) status using highest decayed, missing, filled, primary teeth (dmft) scores at 12 to 59 mo of age. We examined prenatal and cord blood for 76 and 57 mother/infant pairs, respectively. Children 12 to 35 mo of age with "deficient" cord blood (25(OH)D <30 nmol/L) had a mean dmft score twice as high as children who were "nondeficient" at birth (9.3 vs. 4.7; P = 0.002). There was no significant difference in mean dmft scores for children aged 36 to 59 mo with deficient versus nondeficient cord blood 25(OH)D (10.9 vs. 8.7 P = 0.14). There was no significant difference in mean dmft scores for children aged 12 to 35 mo whose mothers had "sufficient" versus "insufficient" 25(OH)D during prenatal visits (9.0 vs. 7.4; P = 0.48). In this small sample, children with deficient vitamin D levels in cord blood had a dmft score at 12 to 35 mo 2-fold higher than children with nondeficient cord blood. Maternal 25(OH)D may influence the primary dentition, and improving vitamin D status in pregnant women might affect ECC rates in their infants.

Distinct subclasses of small GTPases interact with guanine nucleotide exchange factors in a similar manner.

The Ras-related GTPases are small, 20- to 25-kDa proteins which cycle between an inactive GDP-bound form and an active GTP-bound state. The Ras superfamily includes the Ras, Rho, Ran, Arf, and Rab/YPT1 families, each of which controls distinct cellular functions. The crystal structures of Ras, Rac, Arf, and Ran reveal a nearly superimposible structure surrounding the GTP-binding pocket, and it is generally presumed that the Rab/YPT1 family shares this core structure. The Ras, Rac, Ran, Arf, and Rab/YPT1 families are activated by interaction with family-specific guanine nucleotide exchange factors (GEFs). The structural determinants of GTPases required for interaction with family-specific GEFs have begun to emerge. We sought to determine the sites on YPT1 which interact with GEFs. We found that mutations of YPT1 at position 42, 43, or 49 (effector loop; switch I), position 69, 71, 73, or 75 (switch II), and position 107, 109, or 115 (alpha-helix 3-loop 7 [alpha3-L7]) are intragenic suppressors of dominant interfering YPT1 mutant N22 (YPT1-N22), suggesting these mutations prevent YPT1-N22 from binding to and sequestering an endogenous GEF. Mutations at these positions prevent interaction with the DSS4 GEF in vitro. Mutations in the switch II and alpha3-L7 regions do not prevent downstream signaling in yeast when combined with a GTPase-defective (activating) mutation. Together, these results show that the YPT1 GTPase interacts with GEFs in a manner reminiscent of that for Ras and Arf in that these GTPases use divergent sequences corresponding to the switch I and II regions and alpha3-L7 of Ras to interact with family-specific GEFs. This finding suggests that GTPases of the Ras superfamily each may share common features of GEF-mediated guanine nucleotide exchange even though the GEFs for each of the Ras subfamilies appear evolutionarily unrelated.

Idiopathic scoliosis and pineal lesions in Australian children.

PURPOSE: To determine whether treatment of pineal lesions in children is associated with development of idiopathic scoliosis. METHODS: 38 boys and 10 girls with pineal lesions were identified. Their mean age at presentation was 10 years. The pineal pathology varied from cysts and epidermoid to teratoma, germinoma, pineocytoma, and glioblastoma. Treatment ranged from biopsy/extirpation to radiotherapy. RESULTS: 12 patients died. No scoliosis was found in any females or any of the deceased. Two boys had scoliosis: one had a 12-degree right upper thoracic curve with 32-degree kyphosis and the other had a 60-degree right thoracolumbar idiopathic curve, requiring a 2-stage arthrodesis. CONCLUSION: Pineal ablation is not related to the development of idiopathic scoliosis in humans.

Reticular synthesis of porous molecular 1D nanotubes and 3D networks.

Synthetic control over pore size and pore connectivity is the crowning achievement for porous metal-organic frameworks (MOFs). The same level of control has not been achieved for molecular crystals, which are not defined by strong, directional intermolecular coordination bonds. Hence, molecular crystallization is inherently less controllable than framework crystallization, and there are fewer examples of 'reticular synthesis', in which multiple building blocks can be assembled according to a common assembly motif. Here we apply a chiral recognition strategy to a new family of tubular covalent cages to create both 1D porous nanotubes and 3D diamondoid pillared porous networks. The diamondoid networks are analogous to MOFs prepared from tetrahedral metal nodes and linear ditopic organic linkers. The crystal structures can be rationalized by computational lattice-energy searches, which provide an in silico screening method to evaluate candidate molecular building blocks. These results are a blueprint for applying the 'node and strut' principles of reticular synthesis to molecular crystals.

Understanding the influence of polymorphism on phonon spectra: lattice dynamics calculations and terahertz spectroscopy of carbamazepine.

Rigid molecule atomistic lattice dynamics calculations have been performed to predict the phonon spectra of the four polymorphs of carbamazepine, and these calculations predict that there should be differences in the spectra of all four forms. Terahertz spectra have been measured for forms I and III, and there are clearly different features between polymorphs' spectra, that are accentuated at low temperature. While carbamazepine adopts the same hydrogen bonded dimers in all of its known polymorphs, the calculations show that differences in packing arrangements of the dimers lead to changes in the frequency ranges for each type of hydrogen bond vibration, giving a physical explanation to the observed differences between the spectra. Although the agreement between calculated and observed spectra does not allow a definitive characterization of the spectra, it is possible to make tentative assignments of many of the observed features in the terahertz region for the simpler form III; we can only make some tentative assignments of specific modes in the more complex spectrum of form I. While harmonic rigid molecule lattice dynamics shows promise for understanding the differences in spectra between polymorphs of organic molecules, discrepancies between observed and calculated spectra suggest areas of improvement in the computational methods for more accurate modeling of the dynamics in molecular organic crystals.

Second cancers following oral and pharyngeal cancers: role of tobacco and alcohol.

BACKGROUND: The exceptionally high rate of second primary cancers among patients with oral and pharyngeal cancers is well recognized, yet there has been limited epidemiologic study of risk factors for second tumors. PURPOSE: To evaluate the relation of smoking and alcohol consumption to the development of second cancers among this high-risk patient group, we conducted a nested case-control study. METHODS: A total of 1090 patients enrolled in a 1984-1985 population-based, case-control study of oral cancer in four areas of the United States were followed through June 1989 for the occurrence of second primary cancers. Information on tobacco and alcohol consumption was obtained from the original interviews and was updated by follow-up interviews obtained for 80 case patients with second cancers and 189 sex-, study area-, and survival-matched cancer patients free of second cancers (control subjects). RESULTS: Tobacco smoking and alcohol drinking each contributed to risk of second cancers, with the effects of smoking more pronounced than those of alcohol. The odds ratios (ORs) for smoking (adjusted for alcohol) rose with duration and intensity of smoking and were strongest for tumors of the aerodigestive tract (oral cavity, pharynx, esophagus, larynx, and lungs), with ORs reaching 4.7 (95% confidence interval [CI] = 1.4-16) among smokers of 40 or more cigarettes per day for 20 or more years. Current smokers as of the baseline survey experienced a fourfold increased risk of a second aerodigestive tract cancer relative to nonsmokers and former smokers. No reduction in risk was associated with cessation of smoking or drinking at or after the index diagnosis, although the short median interval (27 months) between tumor diagnoses limited observation of the effects due to recent cessation. Risk was significantly reduced, however, 5 years after smoking cessation. Among drinkers, second cancer risk was greatest for beer intake, with an OR for a second aerodigestive tract cancer of 3.8 (95% CI = 1.2-12) for 15 or more beers per week. CONCLUSIONS: Oral and pharyngeal cancer patients with the highest intakes of tobacco and alcohol are the ones most prone to develop second primary cancers. IMPLICATIONS: Avoidance of tobacco smoking and alcohol drinking is the most desirable way not only to prevent primary oral cancers, but also to reduce risk of second cancers of the aerodigestive system.

Racial differences in risk of oral and pharyngeal cancer: alcohol, tobacco, and other determinants.

BACKGROUND: In the United States, Blacks have increasingly higher rates of oral and pharyngeal cancer (oral cancer) than Whites, but determinants of the racial disparity have not been clear. PURPOSE: The purpose of this study was to explore reasons for the higher incidence of oral cancer among Blacks than Whites. METHODS: We used data from a large, population-based case-control study of oral cancer risk factors conducted in four areas of the United States. On the basis of interviews that ascertained characteristics of 1065 oral cancer patients (871 Whites and 194 Blacks) and 1182 controls (979 Whites and 203 Blacks), we examined racial differences in exposure prevalences and relative risks for a number of known etiologic factors, including tobacco and alcohol consumption, diet, and socioeconomic and other variables. To evaluate the extent to which the major risk factors explained the excess risk of oral cancer among Blacks, population-attributable risks were calculated. RESULTS: Differences with respect to alcohol consumption, especially among current smokers, emerged as the most important explanatory variables. After adjusting for smoking, heavy drinking (> or = 30 drinks/week) resulted in a 17-fold increased risk among Blacks and a ninefold increase among Whites. Among drinkers, Blacks tended to drink more than Whites. Also, a higher (P = .01) percentage of Blacks (37%) than Whites (28%) were current smokers, although there were little or no racial differences in relative risks or patterns of use for other smoking variables, including number of cigarettes smoked per day, years of smoking, and age started smoking. From population-attributable risk calculations, we estimated that differences in alcohol and tobacco use account for the bulk of the higher incidence of oral cancer among Blacks in the United States and that, in the absence of alcohol and tobacco, the rates of this cancer according to race (Black, White) and gender would be nearly equal. With regard to other potential etiologic factors, protective effects provided by higher dietary intake of fruits and vitamin C were more pronounced for Whites, while Blacks more often tended to be in sociodemographic and medical or dental health categories associated with increased risk. CONCLUSIONS: These analyses provide evidence that various environmental or lifestyle determinants of oral cancer may contribute to the higher oral cancer rates in Blacks than in Whites in the United States, but that patterns and risks associated with alcohol consumption, particularly among current smokers, are the most important contributors to the excess risk in Blacks. IMPLICATIONS: These findings suggest that the key to prevention of oral and pharyngeal cancers among both Blacks and Whites is reduced intake of alcoholic beverages and, because of strong interactive effects, the cessation of smoking.

Characterization of phagolysosomal simulant fluid for study of beryllium aerosol particle dissolution.

A simulant of phagolysosomal fluid is needed for beryllium particle dissolution research because intraphagolysosomal dissolution is believed to be a necessary step in the cellular immune response associated with development of chronic beryllium disease. Thus, we refined and characterized a potassium hydrogen phthalate (KHP) buffered solution with pH 4.55, termed phagolysosomal simulant fluid (PSF), for use in a static dissolution technique. To characterize the simulant, beryllium dissolution in PSF was compared to dissolution in the J774A.1 murine cell line. The effects of ionic composition, buffer strength, and the presence of the antifungal agent alkylbenzyldimethylammonium chloride (ABDC) on beryllium dissolution in PSF were evaluated. Beryllium dissolution in PSF was not different from dissolution in the J774A.1 murine cell line (p = 0.78) or from dissolution in another simulant having the same pH but different ionic composition (p = 0.73). A buffer concentration of 0.01-M KHP did not appear adequate to maintain pH under all conditions. There was no difference between dissolution in PSF with 0.01-M KHP and 0.02-M KHP (p = 0.12). At 0.04-M KHP, beryllium dissolution was increased relative to 0.02-M KHP (p = 0.02). Use of a 0.02-M KHP buffer concentration in the standard formulation for PSF provided stability in pH without alteration of the dissolution rate. The presence of ABDC did not influence beryllium dissolution in PSF (p = 0.35). PSF appears to be a useful and appropriate model of in vitro beryllium dissolution when using a static dissolution technique. In addition, the critical approach used to evaluate and adjust the composition of PSF may serve as a framework for characterizing PSF to study dissolution of other metal and oxide particles.

Modelling of crystal structure of cis-1,2,3,6 and 3,4,5,6-tetrahydrophthalic anhydrides using lattice energy calculations.

Lattice energy calculations using a model potential were performed to model the crystal structures of cis-1,2,3,6- and 3,4,5,6-tetrahydrophthalic (THP) anhydrides. The optimized molecular models using the DFT method at the B3LYP/6-31G** level were found consistent with the available experimental evidence and allowed all differences observed in crystal packing between cis-1,2,3,6- and 3,4,5,6-THP anhydrides to be reproduced. Calculations provide evidence for the presence of dipole-dipole C=O⋯C=O intermolecular interactions and support the idea that the molecules distort from their ideal geometries, improving packing in both crystals. The search for minima in the lattice energy of both crystals amongst the more common space groups with Z' = 1, using a simulated annealing crystal structure prediction procedure followed by lattice energy minimization showed that the observed structure of 3,4,5,6-THP anhydride (Z' = 2) is the thermodynamically most stable, and allowed us to justify why 3,4,5,6-THP anhydride crystallizes in such a complex structure with 16 molecules in the unit cell. The computational model was successful in predicting the second observed form at 173 K for cis-1,2,3,6-THP anhydride as a polymorph, and could predict several hypothetical structures with Z' = 1 that appear competitive with the observed structures. The results of phonon estimates of zero point intermolecular vibrational energy and entropy suggest that crystal structures of cis-1,2,3,6-THP anhydride cannot be predicted solely on the basis of lattice energy; factors other than thermodynamics favor the observed structures.

Circadian differences in pharmacological blockade of meal-stimulated gastric acid secretion.

The effects of identical morning (08.05 hours) and evening (20.05 hours) meals on intragastric pH were compared in 12 healthy volunteers receiving gastric antisecretory medication. Dosing included continuous intravenous infusion ranitidine (50 mg bolus followed by 12.5 mg/h) or a matching placebo which were randomly administered prior to and following 7 days of treatment with oral omeprazole (40 mg mane). Intragastric pH was monitored continuously using a tethered indwelling pH probe. Subjects were divided into groups, one of which began the pH monitoring session in the morning, the other in the evening. The median 24-h intragastric pH was significantly increased by all active dosing regimens (P less than 0.05). Combined omeprazole and ranitidine produced the highest median pH, 5.92. However, a breakthrough drop in intragastric pH occurred during the evening after all active dosing. Intragastric pH fell prior to and after consumption of the evening meal with median pH values less than 4 during all sessions. The evening meal led to significantly lower intragastric pH compared to the morning meal for omeprazole and the combined omeprazole and ranitidine dosing periods (P less than 0.05). There was no difference between morning and evening pH during the placebo or ranitidine periods. Ranitidine and omeprazole, either alone or in combination, were unable to prevent the meal-stimulated decline in intragastric pH during the evening time period.

Electronic excitations in homopolyatomic bismuth cations: spectroscopic measurements in molten salts and an ab initio CI-singles study

The electronic excitations of the low-valence bismuth cluster cations Bi5(3+), Bi8(2+), and Bi9(5+) have been studied with experimental and theoretical techniques. The UV-visible spectra of the bismuth ions were measured in acidic chloroaluminate melts (mixture of 1-methyl-3-benzyl imidazolium chloride and AlCl3). The spectra of the Bi5(3+) and Bi8(2+) ions agree fairly well with previous reports, but also revealed additional low-energy absorptions. Ab initio methods were employed to assign the experimentally observed electronic transitions of these homopolyatomic bismuth cations. Structures were optimized at the RHF, MP2, and B3LYP levels of theory by using split-valence LANL2DZ basis sets that were augmented with one and two sets of pure d functions. The computed structures agree well with the results of neutron diffraction analyses of melts. Electronically excited states of the three clusters were treated by using the CI-Singles theory. The results of these calculations were used to explain the observed UV-visible spectra. The observed electronic excitations in the UV-visible range are all found to result from transitions involving the molecular orbitals formed by 6p-atomic-orbital overlap. This leads to the necessity of using basis sets that include d-type functions, which allow for an adequate description of the bonding that results from such p-orbital overlap. Spin-orbit coupling becomes increasingly important with increasing atomic number and its consideration is necessary when describing the electronic transitions in clusters of heavy atoms. The calculations show that singlet-triplet transitions, which are made accessible by strong spin-orbit coupling, are responsible for some of the observed absorptions.

White blood cell immunization and anticardiolipin antibody levels in women with recurrent miscarriages.

To determine whether WBC immunization stimulates production of anticardiolipin antibodies, anticardiolipin antibodies were measured before and 6 weeks after WBC immunization. Twenty-four non-pregnant women, who had had recurrent miscarriages for which a definitive cause could not be determined, were immunized with their partner's WBC. No significant differences in levels of anticardiolipin antibodies were detected between paired samples of sera obtained before and 6 weeks after WBC immunization. White cell immunization in nonpregnant women did not stimulate production of anticardiolipin antibodies.

Automated skin lesion screening--a new approach.

Automated melanoma diagnosis is a popular focus of research, with numerous papers describing techniques and results. In our study, we identified two possible problems with the current method of automated diagnosis, where systems are intended to reproduce histopathology results. We propose a new method of identifying problematic skin lesions, namely attempting to reproduce algorithmically the perceptions of dermatologists as to whether the lesion should be excised. In the best case, our initial model reproduced the decision of dermatologists in over 80% of cases. These results suggest that reproducing the decision to excise may be a valuable adjunct to current methodology.

The computation of scatter in mammography by Monte Carlo methods.

A Monte Carlo computer program has been used to calculate the ratio of the scatter-to-primary radiation recorded by a range of image receptors used in mammography. The dependence of this ratio on breast size and photon energy has been investigated and the contributions of different sources of scattered radiation examined. The use of magnification and grid techniques have been included in the program and the performance of the Philips mammographic grid examined in detail. The results of the calculations are in good agreement with the limited experimental data available.

Nine-year mean follow-up of one-stage anteroposterior excision of hemivertebrae in the lumbosacral spine.

Six patients with lumbosacral hemivertebrae were treated by one-stage anterior and posterior excision of the hemivertebrae. Long-term follow-up is reported. Overall, correction of the lumbosacral curve was 46%, including one case of pseudarthrosis and subsequent loss of correction. More importantly, truncal imbalance was restored unless other congenital thoracic anomalies were present. New methods of calculating rib cage shift on the pelvis as well as vertebral column displacement from the sagittal plane are presented.