Solder-joint reliability of HVQFN-packages subjected to thermal cycling

In this work experimental results of thermal cycling tests on HVQFN-packages mounted on printed circuit boards are combined with finite element analyses. Validating the finite element analyses by a selected series of small, medium and large HVQFN-packages assembled on printed circuit boards, allows us to determine the performance of this family. To be able to do that, the discriminating parameters that determine the board level performance of this family need to be understood. The emphasis is on the fatigue life of the soldered interconnections as it is influenced by the thermal stress load, the board thickness, and the dimension of the package. Data from different experimental set-ups are compared. An important parameter in this respect is the inclusion of the base material of the panels. The test loads were set to cycling at −40 °C/+125 °C and −20 °C/+100 °C. The results prove that the essential physical properties governing the fatigue life are the stiffness of the complete assembly and the thermal expansion mismatch between the parts.     

Improved cytotoxicity testing of magnesium materials

Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.     

Knowledge-based interpretation of bioelectrical signals

The integration into one automated system of the qualitative knowledge of the physician, who is accustomed to visually scanning a paper record, with possibly sophisticated signal analysis tools that must replace the visual scanning is addressed. The automated interpretation of bioelectrical signals must combine signal analysis knowledge with knowledge about the application domain of the signal and, as such, requires the knowledge of two experts. The role of event-oriented interpretation and the use of spatial and temporal context is discussed. An architecture for a system tailored to fit the characteristics of automated bioelectrical signal interpretation is described. It contains two separate, cooperating knowledge bases, and it makes use of object-oriented knowledge representation and spatial and temporal operators. An example of the automated detection of epileptogenic electroencephalograph sharp transients is presented.     

Context processing in schizotypal personality disorder: Evidence of specificity of impairment to the schizophrenia spectrum.

Working memory abnormalities, which are particularly pronounced on context processing tasks, appear relatively specific to schizophrenia spectrum illnesses compared with other psychotic disorders. However, the specificity of context processing deficits to schizotypal personality disorder (SPD), a prototype of schizophrenia, has not been studied. The authors administered 3 versions of the modified AX Continuous Performance Test and an N-back working memory test to 63 individuals with SPD and 25 with other personality disorders, as well as 42 healthy controls. For the AX Continuous Performance Test standard and degraded versions, there was a significant Trial Type × Delay × Group interaction, as SPDs made significantly more errors reflecting poor maintenance of context and fewer errors reflecting good maintenance of context. SPDs also demonstrated poor performance on the N-back, especially at the 2-back condition. Context processing errors and N-back accuracy scores were related to disorganization symptoms. These findings, which are quite similar to those previously reported in patients with schizophrenia, suggest that context processing deficits are specific to the schizophrenia spectrum and are not a reflection of overall psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Depression in Parkinson's disease is not accompanied by more corticotropin-releasing hormone expressing neurons in the hypothalamic paraventricular nucleus

BACKGROUND: Depression is frequently encountered in Parkinson's disease (PD). In addition, more than half of the PD patients have a disturbed dexamethasone suppression test, which is associated with increased activity of corticotropin-releasing hormone (CRH) neurons. We recently found an increase in CRH neuron number, CRH-messenger RNA, and vasopressin colocalization in CRH neurons in the paraventricular nucleus (PVN) of depressed patients, which may be involved in the pathogenesis of depression. METHODS: The number of neurons expressing CRH was determined in the PVN of 6 depressed PD patients with a high score (> or = 13) on the Hamilton Depression Rating Scale, 6 nondepressed PD patients, and 6 controls. RESULTS: The three groups did not differ in the number of neurons expressing CRH. CONCLUSIONS: We hypothesize that activation of CRH neurons in the PVN, as we recently observed in idiopathic depression, does not play an essential role in depression in PD.     

Glycerol gangliotomy of the second dorsal cervical root in rats: an experimental study to evaluate a minimal invasive approach for the treatment of the chronic cervicogenic headache

The purpose of this integrated literature review (1980-1997) is to describe and summarize specific nursing interventions that have been devised to aid community-dwelling older adults with self-administration of prescribed medications. Interventions that combine patient education with written information or follow-up phone calls produce the most positive results. By using interventions supported by research, nurses will provide more effective and efficient care to older adults managing medications at home.     

Control of the transmission of Vibrio cholerae and other enteropathogens by foods originating from endemic areas in South America and elsewhere as a model situation.

The cholera-pandemic raging in South and Middle America and endemic cholera in other countries call for measures of health protection of the local population, but particularly with respect to the young, old, pregnant and immunocompromised citizens of countries importing food from the areas where the disease has struck. Instead of harshly barring importation, a more humanitarian policy is recommended, relying on assistance of areas presenting risks, with the introduction of and adherence to rigorous measures of longitudinally integrated microbiological safety assurance. This model is equally applicable to other enteric diseases transmitted by food. Examples are given of how canned foods of neutral pH, fishery products, vegetables and certain fruits should be processed for safety. Importation monitoring strategies, linked to this proactive approach to consumer protection, are briefly summarized.     

The adsorption site of ammonia at copper surfaces

The adsorption of ammonia at copper surfaces was studied using Hartree-Fock-Slater LCAO calculations to investigate ammonia interaction with copper clusters. Important factors influencing ammonia adsorption were established from trends in its behaviour at clusters of different size. Adsorption at different coordination sites was examined in light of these results and it was found that a strong electrostatic contribution directs the ammonia towards lower coordination sites.     

Validation of multifrequency bioelectrical impedance analysis in monitoring fluid balance in healthy elderly subjects

BACKGROUND: Multifrequency Bioelectrical Impedance Analysis (MFBIA) is a novel method to assess body composition in elderly subjects. However, it is unclear whether MFBIA can detect changes in body water compartments in elders. We aimed to determine the within-subject variability of MFBIA and the responsiveness to a diuretic intervention in aged subjects with a stable fluid balance. METHODS: We selected 12 healthy active elderly subjects (5 male, 7 female) with a mean age of 75 years. Total body water and extracellular fluid (ECF) were measured by deuterium oxide- and potassium bromide-dilution techniques. Within-subject variability in total body MFBIA was assessed by performing four measurements at 1, 5, 50, and 100 kHz within a 2-month period. Subsequently, responsiveness of MFBIA to the ECF loss caused by oral administration of 40 mg of furosemide was determined. RESULTS: Within-subject variability in MFBIA at 1, 5, 50, and 100 kHz expressed as standard deviations was 21, 19, 14, and 14 Ohm (omega), respectively. Furosemide caused a mean weight loss of 1.8 +/- 0.6 kg, which resulted in significant increases in impedance of 57 +/- 24 omega at 1 kHz and 37 +/- 12 omega at 100 kHz (p < .001). The responsiveness of MFBIA for the diuretic intervention was best at 5 kHz (responsiveness index = 1.98). CONCLUSIONS: Within-subject variability of MFBIA was small in healthy elderly subjects with stable fluid balance. Responsiveness of MFBIA to 9% furosemide-induced ECF loss was excellent. These data support the necessity for further clinical assessment of the value of MFBIA in monitoring fluid balance in geriatric patients.