Coupling of equatorial Atlantic surface stratification to glacial shifts in the tropical rainbelt.

The modern state of the Atlantic meridional overturning circulation promotes a northerly maximum of tropical rainfall associated with the Intertropical Convergence Zone (ITCZ). For continental regions, abrupt millennial-scale meridional shifts of this rainbelt are well documented, but the behavior of its oceanic counterpart is unclear due the lack of a robust proxy and high temporal resolution records. Here we show that the Atlantic ITCZ leaves a distinct signature in planktonic foraminifera assemblages. We applied this proxy to investigate the history of the Atlantic ITCZ for the last 30,000 years based on two high temporal resolution records from the western Atlantic Ocean. Our reconstruction indicates that the shallowest mixed layer associated with the Atlantic ITCZ unambiguously shifted meridionally in response to changes in the strength of the Atlantic meridional overturning with a southward displacement during Heinrich Stadials 2-1 and the Younger Dryas. We conclude that the Atlantic ITCZ was located at ca. 1°S (ca. 5° to the south of its modern annual mean position) during Heinrich Stadial 1. This supports a previous hypothesis, which postulates a southern hemisphere position of the oceanic ITCZ during climatic states with substantially reduced or absent cross-equatorial oceanic meridional heat transport.

Linkages between atmospheric blocking, sea ice export through Fram Strait and the Atlantic Meridional Overturning Circulation.

As a key persistent component of the atmospheric dynamics, the North Atlantic blocking activity has been linked to extreme climatic phenomena in the European sector. It has also been linked to Atlantic multidecadal ocean variability, but its potential links to rapid oceanic changes have not been investigated. Using a global ocean-sea ice model forced with atmospheric reanalysis data, here it is shown that the 1962-1966 period of enhanced blocking activity over Greenland resulted in anomalous sea ice accumulation in the Arctic and ended with a sea ice flush from the Arctic into the North Atlantic Ocean through Fram Strait. This event induced a significant decrease of Labrador Sea water surface salinity and an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC) during the 1970s. These results have implications for the prediction of rapid AMOC changes and indicate that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait sea ice transport and of the synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models.

Effectiveness of various toothpastes on dentine tubule occlusion.

OBJECTIVE: Dentine hypersensitivity is an increasing problem in dentistry. Several products are available that claim to occlude open dentine tubules and to reduce dentine hypersensitivity. The aim of this study was to investigate the effectiveness of several different products on dentine tubule occlusion using qualitative and quantitative methods. MATERIALS AND METHODS: Dentine discs were prepared from extracted human premolars and molars. The dentine discs were brushed with 6 different experimental toothpastes, 1 positive control toothpaste and 1 negative control without toothpaste; the brushing simulated a total brushing time of 1 year. Half of the discs were etched with lemon juice after toothpaste application. Standardized scanning electron microphotographs were taken and converted into binary black and white images. The black pixels, which represented the open dentine tubules, were counted and statistically evaluated. Then, half of the dentine discs were broken, and the occlusion of the dentine tubules was investigated using energy dispersive X-ray spectroscopy (EDS). RESULTS: The number of open dentine tubules decreased significantly after brushing with 5 of the 6 tested toothpastes. A significant effect was observed after acid erosion for 3 of the 6 tested toothpastes. EDS revealed partly closed dentine tubules after brushing with 3 toothpastes; however, no partly closed dentine tubules were observed after acid erosion. CONCLUSIONS: Some toothpastes are capable of partial dentine tubule occlusion. This occlusion is unstable and can be removed with acid erosion. CLINICAL SIGNIFICANCE: Desensitizing toothpastes are the most common products that are used against dentine hypersensitivity, and these toothpastes affect dentine tubule occlusion.

Observations of Co4+ in a higher spin state and the increase in the Seebeck coefficient of thermoelectric Ca3Co4O9.

Ca3Co4O9 has a unique structure that leads to exceptionally high thermoelectric transport. Here we report the achievement of a 27% increase in the room-temperature in-plane Seebeck coefficient of Ca3Co4O9 thin films. We combine aberration-corrected Z-contrast imaging, atomic-column resolved electron energy-loss spectroscopy, and density-functional calculations to show that the increase is caused by stacking faults with Co4+-ions in a higher spin state compared to that of bulk Ca3Co4O9. The higher Seebeck coefficient makes the Ca3Co4O9 system suitable for many high temperature waste-heat-recovery applications.

Atomic structure of highly strained BiFeO3 thin films.

We determine the atomic structure of the pseudotetragonal T phase and the pseudorhombohedral R phase in highly strained multiferroic BiFeO(3) thin films by using a combination of atomic-resolution scanning transmission electron microscopy and electron energy-loss spectroscopy. The coordination of the Fe atoms and their displacement relative to the O and Bi positions are assessed by direct imaging. These observations allow us to interpret the electronic structure data derived from electron energy-loss spectroscopy and provide evidence for the giant spontaneous polarization in strained BiFeO(3) thin films.

Simulation of spatially resolved electron energy loss near-edge structure for scanning transmission electron microscopy.

Aberration-corrected scanning transmission electron microscopy yields probe-position-dependent energy-loss near-edge structure (ELNES) measurements, potentially providing spatial mapping of the underlying electronic states. ELNES calculations, however, typically describe excitations by a plane wave traveling in vacuum, neglecting the interaction of the electron probe with the local electronic environment as it propagates through the specimen. Here, we report a methodology that combines a full electronic-structure calculation with propagation of a focused beam in a thin film. The results demonstrate that only a detailed calculation using this approach can provide quantitative agreement with observed variations in probe-position-dependent ELNES.

Defining brain mechanical properties: effects of region, direction, and species.

No regional or directional large-deformation constitutive data for brain exist in the current literature. To address this deficiency, the large strain (up to 50%) directional properties of gray and white matter were determined in the thalamus, corona radiata, and corpus callosum. The constitutive relationships of all regions and directions are well fit by an Ogden hyperelastic relationship, modified to include dissipation. The material parameter alpha, representing the non-linearity of the tissue, was not significantly sensitive to region, direction, or species. The average value of the material parameter mu, corresponding to the shear modulus of the tissue, was significantly different for each region, demonstrating that brain tissue is inhomogeneous. In each region, mu, obtained in 2 orthogonal directions, was compared. Consistent with local neuroarchitecture, gray matter showed the least amount of anisotropy and corpus callosum exhibited the greatest degree of anisotropy. Finally, human temporal lobe gray matter properties were determined and compared to porcine thalamic properties. The results show significant regional inhomogeneity at large strains and significant anisotropy in each region tested. The extent of regional anisotropy correlated with the degree of alignment in the local neuroarchitecture. These large strain, regional and directional data should enhance the biofidelity of computational models and provide important information regarding the mechanisms of traumatic brain injury.

The role of dentistry in palliative care of the head and neck cancer patient.

Although palliative care for the terminally ill is based on a multidimensional philosophy to provide whole-person comfort care while maintaining optimal function, it does not usually include dentistry in its team approach. Dentists can have a significant role in the care of these patients by providing total, active comfort care of the oral cavity. The function of the oral cavity is essential to the patient's ability to thrive. Therefore, alleviation of pain and prevention of infection in the oral cavity should be a priority in providing total, active comfort for the patient. The oral problems experienced by the hospice head and neck patient clearly affect the quality of his or her remaining life. Through routine assessments and interventions by a dentist on the palliative care team (Figure 4), comfort care for the patient may be improved by the maintenance of oral hygiene and procedures to hydrate the oral mucosa. In addition, routine dental assessments may identify dental disease and facilitate dental interventions for caries, periodontal disease, oral mucosal problems or prosthetic needs. Attention to such detail may reduce not only the microbial load of the mouth but the risk for pain and oral infection as well. This multidisciplinary approach to palliative care, including a dentist, may reduce the oral debilities that influence the patient's ability to speak, eat or swallow. Not only does maintenance of oral health have impact on the quality of life, which is already challenged by the disease, but it also aids in the ability of patients to thrive for whatever precious time is left to them.

Capillary perfusion pattern and microvascular geometry in heterogeneous hypoxic areas of hypoperfused rat myocardium.

The origin of heterogeneities in tissue oxygenation due to low-flow ischemia was studied in hypoperfused myocardium of anesthetized rats. In frozen sections of myocardial biopsies the localization of increases in NADH fluorescence, an indicator of tissue hypoxia, was compared with microvascular flow distribution and capillary geometry. The latter parameters were accomplished through capillary labeling with indicator dyes in vivo and enzyme-histochemical staining in vitro, respectively. Most NADH-fluorescent areas were found to have developed despite sustained capillary flow. When the fractions of arterial, venous, and intermediate capillary segments were analyzed within circumscribed hypoxic fields (< 200 microns diam), frequencies of 30.7 +/- 6.1, 35.3 +/- 5.3, and 30.8 +/- 5.0%, respectively, were found. In contrast, a significantly higher fraction of arterial segments (63.2 +/- 3.3%) and a lower percentage of venous segments (16.4 +/- 2.5%) were determined in nonhypoxic islands enclosed by hypoxic tissue. These results support the view that the latter zones are located near the arterial portion of the capillary bed where their oxygenation is favored during low-flow states. This effect appears to contribute to the supply heterogeneities in hypoperfused myocardium.

Method for simultaneous determination of the distribution of capillary plasma flow and myocyte redox state (NADH-fluorescence) in the hypoperfused myocardium of the anesthetized rat.

A method is described which allows to observe the pattern of capillary plasma filling simultaneously with the redox state (NADH-fluorescence) of the myocytes in the hypoperfused myocardium. In anesthetized rats the coronary perfusion pressure was reduced to a defined level, the blood plasma labeled with dye-conjugated albumin and a myocardial biopsy-sampled. Freeze-substitution of histological sections allowed to detect the intravascular plasma label as well as the myocyte NADH-fluorescence on a microscopic level. It was found that areas showing increased cellular NADH-fluorescence did not arise in a distribution congruent with zones of failing capillary plasma flow in the hypoperfused myocardium.

Family functioning and psychopathology among adolescents with severe emotional disturbances.

Family psychosocial functioning and its relation to psychopathology among adolescents with severe emotional disturbances (SED) was assessed. Subjects were 353 adolescents with SED, ages 12-18, and their parents. During a semi-structured interview, adolescents were administered Family Adaptability and Cohesion Evaluation Scale (FACES-III), Diagnostic Interview Schedule for Children-Child Version (DISC-C), and the Self-Derogation Scale. Parents were administered FACES-IIII and the Child Behavior Checklist (CBCL) in a phone interview. Results indicated that on the FACES-IIII cohesion dimension, both parents and adolescents perceived their family relations as more disengaged and less connected than did normative families (p less than .001). In contrast, only parent FACES-IIII adaptability scores were significantly more extreme than a normative sample (p less than .01). Additionally, both parent and adolescent cohesion scores were significantly correlated with adolescent psychopathology measures: DISC-C conduct disorder (p less than .01), depression (p less than .05), alcohol/marijuana (p less than .01), and CBCL externalizing symptoms (p less than .01). These relationships did not deviate from linearity.

Substance abuse prevalence and comorbidity with other psychiatric disorders among adolescents with severe emotional disturbances.

Among 547 adolescents with serious emotional disturbances, ages 12 to 18, this study assessed (1) prevalence of DSM-III substance use disorders (i.e., alcohol and marijuana abuse/dependence), and (2) comorbidity with DSM-III Axis I disorders. Factors of age, sex, state location, and type of treatment program also were examined. Data were analyzed by logistic regression. Significant factors (p less than 0.05) associated with severe alcohol or marijuana abuse/dependency diagnosis included (1) residential mental health treatment program, 2.37 Odds Ratio (OR); (2) conduct disorder diagnosis, 2.18 OR; (3) depression diagnosis, 1.75 OR; (4) states, 1.43 OR; (5) age, 1.29 OR; and (6) a depression x facility interaction, 1.91 OR.

Patterns of alcohol abuse among black and white alcoholics.

The drinking practices of a matched sample of 78 Black and 78 White, male, hospitalized alcoholics were compared. The groups were matched on age and educational level; and they were equivalent in terms of marital and employment status, number of times hospitalized for treatment of alcoholism and other neuropsychiatric disorders, and number of arrests. The Alcohol Use Inventory was used to assess drinking practices. Significant multivariate and univariate analysis of variance indicated that (a) Whites reported greater daily consumption of alcohol, a tendency to perceive alcohol as a means of relieving psychological distress, and a greater level of psychological distress as a consequence of alcohol abuse than Blacks; and (b) Blacks reported a tendency to perceive alcohol as a means to improve mental functioning and to experience more serious psychoperceptual withdrawal symptoms than Whites.

Self-reported and self-monitored smoking patterns.

Individual differences in smoking patterns are usually assessed with self-report measures such as Horn's Reasons for Smoking Test, which have not been systematically validated. This paper compares results from several self-report scales with self-monitoring data obtained from 164 smoking clinic subjects who monitored their smoking for at least two days. Self-monitoring data were factor-analyzed and correlated with self-report measures. Most of the hypothesized relationships failed to appear. The Sedative Smoking (tension-reduction) factor of the Reasons for Smoking Test received the strongest support. In general, however, the results did not support the validity of commonly-used self-report scales of smoking motives and situations.

Drinking practices among black and white alcoholics and alcoholics of different personality types.

In order to examine the effects that race and personality type have on self-reported drinking practices, samples of 49 White and 49 Black male alcoholics were matched on age and education, and classified into two personality types according to MMPI scores. The results of multivariate and univariate analyses of variance yielded significant main effects. White alcoholics reported a greater: (a) use of alcohol for symptomatic relief of psychological distress, (b) loss of motor control and tendency to engage in destructive acts, and (c) daily consumption of beverage alcohol than Black alcoholics. Alcoholics with psychiatric-appearing MMPI profiles reported greater: (a) social benefits of alcohol use, (b) alcohol use for symptomatic relief of psychological distress, and (c) perceptual distortions associated with alcohol withdrawal than alcoholics with characterlogical-appearing MMPIs. Results were discussed in terms of need to control confounding effects of biosocial variables in cross-cultural research and implications that these effects may have on the generalizability of alcoholic personality typologies.

Perceptual and cognitive abnormalities in bulimia.

The authors compared 55 bulimic subjects and 55 normal control subjects using the Beck Depression Inventory, a new scale designed to detect cognitive distortions (the Bulimia Cognitive Distortion Scale), and several perceptual and attitudinal measures of body image. There were significant differences between the bulimic and control groups on all measures except estimates of face width. These findings are discussed in terms of a multifactorial theory of the psychopathogenesis of bulimia.

The development of a scale to measure cognitive distortions in bulimia.

The Bulimia Cognitive Distortions Scale (BCDS) was developed to measure irrational beliefs and cognitive distortions associated with bulimia. The final 25-item scale was found to have excellent internal consistency with high item to total correlations and a coefficient alpha of .97. Factor analysis revealed two clear factors measuring cognitive distortions related to automatic eating behaviors and to physical appearance. Data attesting to the convergent and divergent validity of the BCDS are also presented. With 110 subjects (55 bulimics, 55 controls), a discriminant analysis revealed the BCDS to be the only significant variable in predicting group membership, correctly classifying 93.6% of all subjects. The BCDS was also predictive of severity of bulimia as measured by the frequency of binge eating episodes. The potential of the BCDS as both a diagnostic and research instrument is discussed.

On quantifying the magnitude of sex-role endorsement.

The conception of sex-role attributes as multidimensional has led to the development of the median split and various difference score approaches for assigning individuals to sex-rote categories. In response to the criticisms of information loss and imprecision when applying such methods, this report presents a data manipulation (medz) which combines the masculine and feminine scales in an additive rather than subtractive manner, upholds the continuous nature of the variables, and utilizes the median split for categorization. Comparisons of this technique with the t ratio, difference/median split, and direct difference approaches indicate greater differentiation among androgynous subjects when assessed according to the medz. An application of the process and some rationale for its implementation are provided.

[The unaffected primary rejection of xenogeneic kidney transplants in the closely related fox-dog species system]. / Die unbeeinflusste Primärabstossung xenogener Nierentransplantate im nah verwandten Speziessystem Fuchs - Hund.

The present study reports of three kinds of experiments of unaffected primary rejection of xenogenous kidney transplanats in the close-related fox-dog species system. The issue is whether there is a relation between the amount of grafted parenchyma and the immune induced potency, that is whether the course of rejection of transplanted single kidneys (group I a) differs from the course after en-bloc transplantation of both kidneys (group I b). In group II alterations of blood chemism and behavior of humoral antibodies are followed in dogs to which a fox kidney was transplanted, while keeping their own functioning kidneys. This experiment is to give information whether the uremic syndrome influences the development of humoral immunity, and what changes of blood chemism may primarily be related to destruction of the graft, under the condition of absent uremia. Untreated graft recipients survived for 5,4 +/- 0,49 days (n = 5) when single kidneys were transplanted (group I a), and 5,2 +/- 0,75 days (n = 5) when both kidneys were grafted en-bloc (group I b). As to the rejecting reactions, both groups are almost equal: the increasing functional failure causes a fast increase of creatinine and urea nitrogen; alkaline phosphatase and LDH show distinct alterations, related to the progress of the graft's destruction. Decrease of albumin level and loss of cholinesterase activity indicate an impaired hepatic function as reaction to uremic intoxication. Gamma-globulins and leucocytes show alterations that can be related to non-specific inflammatory reactions. The immunologically specific initial lymphopenia suggests that after revascularization these cells migrate to the graft, and later react with antigenic structures of vascular endothelium and still later with those of the organ cells. Cytotoxic antibodies appear on the 4th postoperative day in increasing amount. Post mortem histologic examination shows round cell infiltrates in the vastly necrotic renal parenchyma. When the recipient's kidneys are kept in situ and a fox kidney is transplanted (group II) uremia is avoided and the animals survive. During the 30-days period of observation, that is longer than the term of rejection, the titer of cytotoxic antibodies remains stable or tends to increase. LDH and alkaline phosphatase show characteristic changes that are considered sequels from destructed transplantate. The experiments show, aside from certain reservations, that the donor-host combination fox-dog is suitable to serve as preclinic model for human transplantation using xenogenous donors of organs, i. e. anthropoid primates.