Hand, space and attentional asymmetries in goal-directed manual aiming

Two experiments were conducted to explore the interaction of the two cerebral hemispheres in motor control, by examining hand, space and attentional asymmetries in goal-directed aiming. In Experiment 1, right-handed subjects moved to targets more quickly with their right hand than their left hand. In addition, each hand was faster when moving in its own hemispace. Although in a control condition, movements were initiated more quickly with the left hand, visual distractors disrupted left hand performance more than right hand performance. For contralateral aiming, ipsilateral distractors caused the greatest interference. In Experiment 2, when targets and distractors were all presented at the midline, a right hand advantage was found for movement time along with a left hand advantage for reaction time, independent of target and distractor location. Our findings are discussed in terms of a right hemisphere role in movement preparation and the allocation of attention in space, and greater left hemisphere involvement in movement execution.     

The arterioportal fistula syndrome: clinicopathologic features, diagnosis, and therapy

BACKGROUND & AIMS: Arterioportal fistulas (APFs) are rare vascular disorders of the mesenteric circulation. The aim of this study was to determine the etiology, anatomical location, and main symptom at presentation of APFs, and analyze the various modes of treatment. METHODS: The etiology, clinical presentation, radiographs, and treatment of 12 patients with APFs are reported in detail, and another 76 cases published since 1980 are reviewed. RESULTS: APFs result from trauma (n = 25, 28%), iatrogenic procedures (n = 14, 16%), congenital vascular malformations (n = 13, 15%), tumor (n = 13, 15%), aneurysm (n = 12, 14%), and other causes (n = 11, 12%). The origin of APFs is the hepatic artery in the majority of patients (n = 56, 65%). The main symptoms at presentation are lower or upper gastrointestinal bleeding (n = 29, 33%), ascites (n = 23, 26%), heart failure (n = 4.5%), or diarrhea (n = 4.5%). Radiological intervention provides definitive treatment in 42% (n = 33) of patients, whereas the remainder are treated by surgery alone (n = 27, 31%) or a combination of radiological intervention and surgery (n = 8, 9%). CONCLUSIONS: APFs result in a protean syndrome variously combining portal hypertension and other hemodynamic imbalances (heart failure, intestinal ischemia). Single or multiple interventional radiological procedures using arterial and/or venous approaches allow definitive treatment of most APFs. With increasing technological advances, it is anticipated that surgery will only be indicated in rare instances after failure of radiological intervention(s).     

Early intervention for spelling problems: Teaching functional spelling units of varying size with a multiple-connections framework.

Poor spellers in 2nd grade (n?=?128) participated in 24 20-min sessions that included (a) direct instruction in the alphabet principle (most frequent phoneme-spelling connections); (b) modeling of different approaches, singly and in combination, for developing connections between spoken and written words for 48 words ordered by sound-spelling predictability; and (c) practice in composing. Results of this multilayered intervention showed that (a) more than 1 way of developing sound-spelling connections is effective in teaching spelling but that after training in the alphabet principle, combining whole word and onset-rime training is most effective in achieving transfer of the alphabet principle across word contexts; (b) functional spelling units of not only a single letter but also 2 or more letters are important in beginning spelling; and (c) training in spelling transfers to composition and word recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erbium-doped silicon and porous silicon for optoelectronics

Silicon forms the backbone of the microelectronics industry, and possibly, of the optoelectronics industry, hitherto dominated by III/V materials. One of the remaining goals is to build an optical source in silicon. Erbium exhibits luminescent 1.54 μm intra-4f transitions in both silicon and porous silicon. This paper reviews the work which has been carried out in this field and discusses some possible additional applications of erbium-doped silicon in optoelectronics, such as a novel on-chip temperature sensor.     

Apoptosis in the failing human heart

BACKGROUND: Loss of myocytes is an important mechanism in the development of cardiac failure of either ischemic or nonischemic origin. However, whether programmed cell death (apoptosis) is implicated in the terminal stages of heart failure is not known. We therefore studied the magnitude of myocyte apoptosis in patients with intractable congestive heart failure. METHODS: Myocardial samples were obtained from the hearts of 36 patients who underwent cardiac transplantation and from the hearts of 3 patients who died soon after myocardial infarction. Samples from 11 normal hearts were used as controls. Apoptosis was evaluated histochemically, biochemically, and by a combination of histochemical analysis and confocal microscopy. The expression of two proto-oncogenes that influence apoptosis, BCL2 and BAX, was also determined. RESULTS: Heart failure was characterized morphologically by a 232-fold increase in myocyte apoptosis and biochemically by DNA laddering (an indicator of apoptosis). The histochemical demonstration of DNA-strand breaks in myocyte nuclei was coupled with the documentation of chromatin condensation and fragmentation by confocal microscopy. All these findings reflect apoptosis of myocytes. The percentage of myocytes labeled with BCL2 (which protects cells against apoptosis) was 1.8 times as high in the hearts of patients with cardiac failure as in the normal hearts, whereas labeling with BAX (which promotes apoptosis) remained constant. The near doubling of the expression of BCL2 in the cardiac tissue of patients with heart failure was confirmed by Western blotting. CONCLUSIONS: Programmed death of myocytes occurs in the decompensated human heart in spite of the enhanced expression of BCL2; this phenomenon may contribute to the progression of cardiac dysfunction.     

The importance of geriatrics to family medicine: a position paper by the Group on Geriatric Education of the Society of Teachers of Family Medicine

The role of geriatrics and geriatricians in family medicine remains unsettled. Despite a rapidly aging population, a tremendous shortage now exists of faculty with interest and expertise in geriatrics. Relatively few family practice residents choose to enter geriatric fellowship programs, and federal funding for such programs has been reduced. Despite accreditation requirements, residency programs are not always able to provide the range of geriatric experiences needed to properly prepare graduates to provide care for the broad range of older patients. Medical students' exposure to geriatrics remains limited. The Group on Geriatric Education of the Society of Teachers of Family Medicine believes that family medicine faculty must recognize and be committed to the notion that geriatrics is integral to family medicine. Both undergraduate and residency training programs should emphasize experience with geriatric patients in multiple settings. In particular, the nursing home should not be the main focus of geriatric training. The small number of certified geriatric faculty will be able to provide leadership, but a broad range of faculty must become involved in teaching geriatrics. Faculty development activities and continuing education programs to foster the necessary expertise will be essential to the accomplishment of this task.     

Silicon bipolar chipset for SONET/SDH 10 Gb/s fiber-opticcommunication links

High-speed multiplexers, demultiplexers, frequency dividers, mixers, and amplifiers are key electronic components in high-speed fiber-optic communications systems such as SONET/SDH. In this paper, we present several important digital and analog integrated circuits (IC) which have been developed for use in SONET/SDH 10 Gb/s optical communication links. The circuits have been fabricated in MOSAIC 5E, an advanced silicon bipolar technology (f_T=26 GHz). The resulting chipset which amounts to a total of 10 IC's consists of multiplexers, demultiplexers, a regenerative frequency divider (2:1), a dual output limiting amplifier, and two different types of mixers for clock extraction. Specifically, the design and performance of these IC's and a hybrid clock recovery module are discussed. The high performance and potential low cost of this research chipset show that advanced silicon bipolar circuit technology can play an important role in future multigigabit fiber-optic communication systems     

Pitfalls and complications of esophageal prosthesis, laser therapy, and dilation

Although often diagnosed and treated by gastroenterologists, thoracic surgeons should be skilled partners in the management of esophageal obstruction. Knowledge of pitfalls and complications of any procedure is a prerequisite to success. This article focuses on problems encountered in dilatation, laser ablation, and stenting of esophageal strictures. Dilatation of both benign and malignant strictures requires knowledge of the different types of dilators and the ability to adapt to different stricture characteristics. Although lower morbidity makes laser ablation of malignant obstruction attractive, this author finds its use to be restrictive. The advent of expandable metal stents offers the potential for fewer early complications when compared with plastic protheses but, as discussed, morbidity may be different rather than less.