bluuebunny/crossref_metadata_2025_split huggingface dataset:
End‐of‐life decision‐making in individuals with Locked‐in syndrome in the acute period after brainstem stroke
Authors: Anderson J. F. I. , Augoustakis L. V. , Holmes R. J. , Chambers B. R. 
Published: March 2009

AbstractLocked‐in syndrome (LIS) is commonly associated with a poor prognosis, particularly if the aetiology is stroke. Dealing with individuals with LIS and a poor prognosis raises the issue of introducing end‐of‐life discussions with the patient and/or family in the acute period of the illness. Existing literature regarding LIS provides little guidance about end‐of‐life decision‐making in the acute management phase. We aim to provide some guidance for clinicians holding end‐of‐life discussions in the acute management period. We report two cases of relatively young individuals with LIS secondary to brainstem stroke. Both cases had a very poor prognosis and end‐of‐life discussions were commenced by the treating team in the acute phase. Despite the severity of their conditions, in neither case were end‐of‐life discussions well tolerated by the family in the weeks following admission. We suggest that LIS patients and their families, who have chosen to persist with full medical management after diagnosis of LIS, should be provided with sufficient time to adjust to the catastrophic changes that have occurred before further end‐of‐life discussions are pursued. Education and support are likely to be highly beneficial in the acute period post stroke as they allow the patient and family to develop a realistic understanding of the likely outcomes of their decisions.
An Australian cardiovascular risk equation for type 2 diabetes: the Fremantle Diabetes Study
Authors: Davis W. A. , Knuiman M. W. , Davis T. M. E. 
Published: March 2009

AbstractBackground: There is no valid cardiovascular disease (CVD) risk prediction equation for Australians with diabetes. The aim of this study is to develop and validate a multivariate risk function for 5‐year cardiovascular risk prediction in Australian type 2 diabetes patients.Methods: The Fremantle Diabetes Study is a community‐based longitudinal observational study. A total of 1240 type 2 diabetic patients (95.8% of the baseline cohort) with all required risk factor data were followed from baseline (1993–1996) for 5 years or until they experienced a cardiovascular event or died, whichever came first. CVD during follow up was defined as hospitalization for/with myocardial infarction or stroke, and death from cardiac or cerebrovascular causes or sudden death. Validation of the algorithm was performed on an independent diabetic cohort from the Busselton Health Study.Results: During 5570 patient‐years of follow up, 185 (14.9%) had at least one CVD event and 175 (14.1%) died (57.7% from CVD). Variables in the final model comprised age, sex, prior CVD, ln(urinary albumin : creatinine ratio), lnHbA1c, ln(high density lipoprotein‐cholesterol), Southern European ethnic background and Aboriginality. The mean 5‐year predicted risk of a CVD event was 15.5%. Applied to the Busselton cohort, discrimination of the model was good (AUC = 0.84, P < 0.001) as was the goodness‐of‐fit (Hosmer–Lemeshow Ĉ‐test, P= 0.85) and accuracy (mean squared error (95% confidence interval) = 0.09 (0–0.76)). The positive and negative predictive values for a 10% 5‐year CVD risk cut‐off were 23.4% and 97.7% respectively.Conclusion: This simple diabetes‐specific 5‐year CVD risk equation is the first validated, population‐based Australian model. It should have a role in diabetes management in primary and specialist care.
Acidosis in the hospital setting: is metformin a common precipitant?
Authors: Scott K. A. , Martin J. H. , Inder W. J. 
Published: March 2009

AbstractBackground: Acidosis is commonly seen in the acute hospital setting, and carries a high mortality. Metformin has been associated with lactic acidosis, but it is unclear how frequently this is a cause of acidosis in hospitalized inpatients. The aim of this study is to explore the underlying comorbidities and acute precipitants of acidosis in the hospital setting, including the relationship between type 2 diabetes (T2DM) and metformin use.Methods: Retrospective review. Cases of acidosis were identified using the hospital discharge code for acidosis for a 3‐month period: October–December 2005.Results: A total of 101 episodes of acidosis were identified: 29% had isolated respiratory acidosis, 31% had metabolic acidosis and 40% had a mixed respiratory and metabolic acidosis. There were 28 cases of confirmed lactic acidosis. Twenty‐nine patients had T2DM, but only five of the subjects with T2DM had lactic acidosis; two were on metformin. The major risk factors for development of lactic acidosis were hepatic impairment (OR 33.8, P = 0.01), severe left ventricular dysfunction (OR 25.3, P = 0.074) and impaired renal function (OR 9.7, P = 0.09), but not metformin use.Conclusion: Most cases of metabolic and lactic acidosis in the hospital setting occur in patients not taking metformin. Hepatic, renal and cardiac dysfunction are more important predictors for the development of acidosis.
Measuring the quality of hospital care: an inventory of indicators
Authors: Copnell B. , Hagger V. , Wilson S. G. , Evans S. M. , Sprivulis P. C. , Cameron P. A. 
Published: March 2009

AbstractBackground: Development of indicators to measure health‐care quality has progressed rapidly. This development has, however, rarely occurred in a systematic fashion, and some aspects of care have received more attention than others. The aim of this study is to identify and classify indicators currently in use to measure the quality of care provided by hospitals, and to identify gaps in current measurement.Methods: A literature search was undertaken to identify indicator sets. Indicators were included if they related to hospital care and were clearly being collected and reported to an external body. A two‐person independent review was undertaken to classify indicators according to aspects of care provision (structure, process or outcome), dimensions of quality (safety, effectiveness, efficiency, timeliness, patient‐centredness and equity), and domain of application (hospital‐wide, surgical and non‐surgical clinical specialities).Results: 383 discrete indicators were identified from 22 source organizations or projects. Of these, 27.2% were relevant hospital‐wide, 26.1% to surgical patients and 46.7% to non‐surgical specialities, departments or diseases. Cardiothoracic surgery, cardiology and mental health were the specialities with greatest coverage, while nine clinical specialities had fewer than three specific indicators. Processes of care were measured by 54.0% of indicators and outcomes by 38.9%. Safety and effectiveness were the domains most frequently represented, with relatively few indicators measuring the other dimensions.Conclusion: Despite the large number of available indicators, significant gaps in measurement still exist. Development of indicators to address these gaps should be a priority. Work is also required to evaluate whether existing indicators measure what they purport to measure.
Probabilistic high cycle fatigue behaviour of nodular cast iron containing casting defects
Authors: NASR A. , BOURAOUI CH. , FATHALLAH R. , NADOT Y. 
Published: March 2009

ABSTRACTTheoretical and experimental investigations were combined to characterize the influence of surface casting defects (shrinkages) on the high cycle fatigue (HCF) reliability. On fracture surfaces of fatigue samples, the defect is located at the surface. The shape used for the calculation is a spherical void with variable radius. Finite‐element simulations were then performed to determine stress distribution around defects for different sizes and different loadings. Correlated expressions of the maximum hydrostatic stress and the amplitude of the shear stress were obtained by using the response surface technique. The loading representative point in the HCF criterion was then transformed into a scattering surface, which has been obtained by a random sampling of the defect sizes. The HCF reliability has been computed by using the Monte Carlo simulation method. Tension and torsion fatigue tests were conducted on nodular cast iron with quantification of defect size on the fracture surface. The S–N curves show a large fatigue life scattering; shrinkages are at the origin of the fatal crack leading to the final failure. The comparison of the computed HCF reliability to the experimental results shows a good agreement. The capability of the proposed model to take into account the influence of the range of the defect sizes and the type of its statistical distribution has been demonstrated. It is shown that the stress distribution at the fatigue limit is log‐normal, which can be explained by the log‐normal defect distribution in the nodular cast iron tested.
An invariant‐based approach for high‐cycle fatigue calculation
Authors: CRISTOFORI A. , TOVO R. 
Published: March 2009

ABSTRACTFatigue failures of in‐service components are frequently due to multiaxial loadings; therefore, damage quantification in such conditions is important to many industrial applications. In this work a multiaxial criterion suitable for high‐cycle fatigue assessment is formalized. It makes use of hydrostatic stress component and deviatoric stress component to estimate fatigue damage. A new formulation for the equivalent amplitude of the deviatoric component is formalized and compared with definitions proposed by Deperrois and Li and De Freitas. Damage evaluation procedure is discussed for deterministic loads and explicit analytical formulation is presented for sinusoidal loadings. Fatigue criterion is applied to experimental data taken from literature, related to several materials subjected to either in‐phase or out‐of‐phase loads. It is shown that the new approach gives good predictions for both smooth and notched specimens. A similar comparison between experimental and theoretical results is also presented for other common criteria. It appears that the quality of the fatigue assessments obtained with the present criterion is better or, at most, similar to that of the other criteria analysed.
A multiaxial fretting fatigue test for spline coupling contact
Authors: WAVISH P. M. , HOUGHTON D. , DING J. , LEEN S. B. , WILLIAMS E. J. , McCOLL I. R. 
Published: March 2009

ABSTRACTA novel fretting fatigue experimental methodology is presented for mimicking the salient fretting variables for arbitrary axial locations within a complex spline coupling geometry, under combined torque, axial loading and rotating bending moment. The approach permits the simulation, in a simplified test arrangement, of the superimposed multiaxial fretting conditions between the spline teeth. This is achieved via the combination of a low frequency in‐plane cyclic normal clamping load and a higher frequency out‐of‐plane cyclic fatigue stress. The latter is known from spline fatigue tests to play a critical role, along with torque and axial loads, in fretting fatigue cracking of splines.
Fatigue fracture toughness of metals
Authors: TROSHCHENKO V. T. 
Published: March 2009

ABSTRACTThe paper considers the peculiarities of fatigue crack propagation and final fracture of metals under cyclic loading. It is shown that the value of the fatigue fracture toughness of steels in an embrittled state is appreciably lower than that of the fracture toughness under static loading. A model of the transition from stable to unstable fatigue crack propagation is justified.
Corticomotor excitability of back muscles is affected by intervertebral disc lesion in pigs
Authors: Hodges Paul W. , Galea Mary P. , Holm Sten , Holm Allison Kaigle 
Published: March 2009

AbstractMorphological and behavioural changes in back muscles are common in back pain and injury. Recent data indicate a rapid reduction in the size of the multifidus, a deep back muscle, within 3 days of experimental intervertebral disc (IVD) injury in pigs. A reduced neural drive may contribute to this. We investigated changes in corticomotor excitability following IVD lesion by evaluation of the response of back muscles to electrical stimulation of the motor cortex. Motor evoked potentials (MEPs) were studied in 12 Swedish landrace pigs before injury, immediately after abdominal incision, immediately after L3‐4 IVD lesion with a scalpel, and 15 min later. In two animals, responses were also evoked by descending volleys excited at the level of the mastoid processes (cervicomedullary evoked potentials) without motor cortex activation. In five animals, a sham procedure was followed without IVD lesion. MEPs were recorded in short (deep) and long (superficial) fibres of the multifidus at L3‐5 on the lesioned side and at L4 contralaterally with intramuscular wire electrodes. Although the MEP amplitude increased in several muscles after incision, at 15 min after IVD lesion only the MEP amplitude of the deep L4 multifidus on the lesioned side was increased [36% (SD 15%), P < 0.05]. There were no changes in MEP amplitude after 15 min at adjacent or contralateral levels. The response to cervicomedullary stimulation reduced slightly. This suggests that the increased MEP amplitude was due to changes in cortical excitability. These data indicate that IVD lesion induces localized increases, and not decreases, in the excitability of cortical inputs to the deep paraspinal muscles that cross a lesioned disc.
Attenuated human auditory middle latency response and evoked 40‐Hz response to self‐initiated sounds
Authors: Baess Pamela , Widmann Andreas , Roye Anja , Schröger Erich , Jacobsen Thomas 
Published: March 2009

AbstractFor several modalities, it has been shown that the processing of sensory information generated by our own actions is attenuated relative to the processing of sensory information of externally generated stimuli. It has been proposed that the underlying mechanism builds predictions about the forthcoming sensory input and forwards them to the respective sensory processing levels. The present study investigated whether early auditory processing is suppressed by the top‐down influences of such an internal forward model mechanism. To this end, we compared auditory middle latency responses (MLRs) and evoked 40‐Hz responses elicited by self‐initiated sounds with those elicited by externally initiated but otherwise identical sounds. In the self‐initiated condition, the amplitudes of the Pa (27–33 ms relative to sound onset) and Nb (40–46 ms) components of the MLRs were significantly attenuated when compared to the responses elicited by click sounds presented in the externally initiated condition. Similarly, the evoked activity in the 40‐Hz and adjacent frequency bands was attenuated. Considering that previous research revealed subcortical and auditory cortex contributions to MLRs and 40‐Hz responses, our results support the existence of auditory suppression effects with self‐initiated sounds on temporally and structurally early auditory processing levels. This attenuation in the processing of self‐initiated sounds most probably contributes to the optimal processing of concurrent external acoustic events.
Expression of Zif268 in the granule cell layer of the adult mouse olfactory bulb is modulated by experience
Authors: Busto Germain U. , Elie Julie E. , Kermen Florence , Garcia Samuel , Sacquet Joëlle , Jourdan François , Marcel Dominique , Mandairon Nathalie , Didier Anne 
Published: March 2009

AbstractBehavioral and physiological evidence indicates that odor processing in the main olfactory bulb is influenced by olfactory experience. At the cellular level, changes in inhibitory influence exerted by granular interneurons may contribute to restructuring odor representations. To assess experience‐dependent modulation in the responsiveness of granule cells, we measured the level and spatial distribution of odor‐induced expression of the immediate–early gene Zif268 in the granule cell layer of adult mice submitted or not to olfactory discrimination conditioning. We first show that stimulation by the reinforced odorant in conditioned animals did not induce any increase in Zif268 expression in contrast to stimulation with an unfamiliar odorant which induced an odor‐specific three‐fold increase in Zif268 expression. The same lack of Zif268 induction was observed in animals exposed to odorants without learning, indicating that familiarity to the odorant with or without conditioning similarly reduced responsiveness of granule cells to odorant stimulation. Second, conditioning induced a spatial reorganization of Zif268‐positive cells leading to higher contrast and significant enlargement of their distribution pattern. The latter effect was also present in animals exposed to the odorants without conditioning but was significantly weaker. Taken together, these data indicate that distinct populations of granule cells are solicited by odorant processing, depending on its familiarity or behavioral significance. Finally, we report that the expression pattern of Zif268 in the granule cell layer is constrained by anteroposterior and dorsolateral gradients in cell density, pointing to anatomical and possibly functional disparity within the layer.
On the positive side of error processing: error‐awareness positivity revisited
Authors: Shalgi Shani , Barkan Ido , Deouell Leon Y. 
Published: March 2009

AbstractPerformance errors are indexed in the brain even if they are not consciously registered, as demonstrated by the error‐related negativity (ERN or Ne) event‐related potential. It has recently been shown that another response‐locked potential, the error positivity (Pe), follows the Ne, but only in those trials in which the participants consciously detect making the error (‘Aware Errors’). In the present study we generalize these findings to an auditory task and investigate possible caveats in the interpretation of the Pe as an index of error awareness. In an auditory Go/No‐Go error‐awareness task (auditory EAT) participants pressed an additional ‘fix error’ button after noticing that they had made an error. As in visual tasks, the Ne was similar for aware (‘fixed’) and unaware (‘unfixed’) errors, while the Pe was enhanced only for Aware Errors. Within subjects, the Ne and Pe behaved in similar fashions for auditory and visual errors. A control condition confirmed that the awareness effect was not due to the requirement to report error awareness. These results reinforce the evidence in favor of the Pe as a correlate of conscious error processing, and imply that this process is not modality‐specific. Nevertheless, single‐trial analysis suggested that the Pe may be a delayed P3b related to stimulus processing rather than to response monitoring.
The maintenance of specific aspects of neuronal function and behavior is dependent on programmed cell death of adult‐generated neurons in the dentate gyrus
Authors: Kim Woon Ryoung , Park Ok‐hee , Choi Sukwoo , Choi Se‐Young , Park Soon Kwon , Lee Kea Joo , Rhyu Im Joo , Kim Hyun , Lee Yeon Kyung , Kim Hyun Taek , Oppenheim Ronald W. , Sun Woong 
Published: March 2009

AbstractA considerable number of new neurons are generated daily in the dentate gyrus (DG) of the adult hippocampus, but only a subset of these survive, as many adult‐generated neurons undergo programmed cell death (PCD). However, the significance of PCD in the adult brain for the functionality of DG circuits is not known. Here, we examined the electrophysiological and behavioral characteristics of Bax‐knockout (Bax‐KO) mice in which PCD of post‐mitotic neurons is prevented. The continuous increase in DG cell numbers in Bax‐KO mice resulted in the readjustment of afferent and efferent synaptic connections, represented by age‐dependent reductions in the dendritic arborization of DG neurons and in the synaptic contact ratio of mossy fibers with CA3 dendritic spines. These neuroanatomical changes were associated with reductions in synaptic transmission and reduced performance in a contextual fear memory task in 6‐month‐old Bax‐KO mice. These results suggest that the elimination of excess DG neurons via Bax‐dependent PCD in the adult brain is required for the normal organization and function of the hippocampus.
Depth‐dependent detection of microampere currents delivered to monkey V1
Authors: Tehovnik Edward J. , Slocum Warren M. 
Published: March 2009

AbstractMonkeys can detect electrical stimulation delivered to the striate cortex (area V1). We examined whether such stimulation is layer dependent. While remaining fixated on a spot of light, a rhesus monkey was required to detect a 100‐ms train of electrical stimulation delivered to a site within area V1. A monkey signaled the delivery of stimulation by depressing a lever after which he was rewarded with a drop of apple juice. Control trials were interleaved during which time no stimulation was delivered and the monkey was rewarded for not depressing the lever. Biphasic pulses were delivered at 200 Hz, and the current was typically at or < 30 μA using 0.2‐ms cathode‐first biphasic pulses. For some experiments, the pulse duration was varied from 0.05 to 0.7 ms and anode‐first pulses were used. The current threshold for detecting cathode‐first pulses 50% of the time was the lowest (< 10 μA) when stimulation was delivered to the deepest layers of V1 (between 1.0 and 2.5 mm below the cortical surface). Also, the shortest chronaxies (< 0.2 ms) and the shortest latencies (< 200 ms) for detecting the stimulation were observed at these depths. Finally, anode‐first pulses were most effective at evoking a detection response in superficial V1 and cathode‐first pulses were most effective at evoking a detection response in deep V1 (> 1.75 mm below the cortical surface). Accordingly, the deepest layers of V1 are the most sensitive for the induction of a detection response to electrical stimulation in monkeys.
The dorsomedial hypothalamic nucleus is not necessary for food‐anticipatory circadian rhythms of behavior, temperature or clock gene expression in mice
Authors: Moriya Takahiro , Aida Reiko , Kudo Takashi , Akiyama Masashi , Doi Masao , Hayasaka Naomi , Nakahata Norimichi , Mistlberger Ralph , Okamura Hitoshi , Shibata Shigenobu 
Published: March 2009

AbstractCircadian rhythms in mammals are regulated by a light‐entrainable circadian pacemaker in the hypothalamic suprachiasmatic nucleus and food‐entrainable oscillators located elsewhere in the brain and body. The dorsomedial hypothalamic nucleus (DMH) has been proposed to be the site of oscillators driving food‐anticipatory circadian rhythms, but this is controversial. To further evaluate this hypothesis, we measured clock gene, temperature and activity rhythms in intact and DMH‐ablated mice. A single 4‐h midday feeding after an overnight fast inducedmPer1andmPer2mRNA expression in the DMH, arcuate nucleus, nucleus of the solitary tract and area postrema, and reset daily rhythms ofmPer1,mPer2andmBMAL1in the DMH, arcuate and neocortex. These rhythms persisted during 2 days of food deprivation after 12 days of scheduled daytime feeding. Acute induction of DMHmPer1andmPer2wasN‐methyl‐d‐aspartate (NMDA) receptor‐dependent, whereas rhythmic expression after 6 days of restricted feeding was not. Thermal DMH lesions did not affect acute induction or rhythmic expression of clock genes in other brain regions in response to scheduled daytime feeding. DMH lesions attenuated mean daily activity levels and nocturnality but did not affect food‐anticipatory rhythms of activity and body temperature in either light–dark or constant darkness. These results confirm that the DMH and other brain regions express circadian clock gene rhythms sensitive to daytime feeding schedules, but do not support the hypothesis that DMH oscillations drive food‐anticipatory behavioral or temperature rhythms.