Modeling of a New Telerobot

This paper deals with the modeling of a robot with a new kinematicdesign. All joint movements in this robot are transmitted via concentrictubes and bevel gears. D'Alembert's principle is used to derivethe equations of motion for rigid and elastic models, consideringthe elastic deflections of the arms and inner tubes. Implementing therecursive algorithm, both symbolical and numerical methods were tested.The advantages and problems are discussed. In order to verify the model,simulation results are compared with measurements.     

Variability in the interpretation of thorax radiography in a primary care medical community and its reference radiologists

OBJECTIVE: To know the variability in the interpretation (normal/pathological) of posteroanterior view chest radiograph and the associated factors between a medical primary care community and a Gold Standard (GS) from 3 reference radiologists. DESIGN: Crossover study. SETTING: Primary care. Teaching health centers of Elche. METHODS: Interobserver percentage agreement (IPA) and Kappa statistic (K) were used to analyse the interobserver agreement (IA) between the GS and every of the participants in interpretation of 100 radiographs. Intraobserver variability was assessed with a second review. Using uni and multivariant analysis some possibly associated factors were studied. RESULTS: Overall IPA and K were 71.3% (CI 95%: 69.2-73.3) and 0.41 (CI 95%: 0.36-0.46) respectively. Time employed in radiographs reading and time passed after medicine studies finished were independently and significantly associated to higher and lower interobserver agreement results respectively, whereas recent professional experience, permanent job and age were not associated. Professional training is the variable that most explain the inter and intraobserver variability. CONCLUSIONS: Overall IA is acceptable. The IA showed by the participants trained under the MIR system is good but the IA achieved by the rest of participants is not acceptable. It is necessary a training which increase the clinical competence, as it does MIR training.     

Bursting and tonic discharges in two classes of reticular thalamic neurons

1. Two types of cat reticular (RE) thalamic cells were disclosed by means of intracellular recordings under urethan anesthesia. The RE neurons were identified by their typical depolarizing spindle oscillations in response to synchronous stimulation of the internal capsule. 2. In type I neurons (n = 41), depolarizing current pulses induced tonic firing at the resting or slightly depolarized membrane potential (Vm) and triggered high-frequency spike bursts at a Vm more negative than -75 mV. As well, these cells discharged rebound bursts at the break of a hyperpolarizing current pulse. Internal capsule stimulation elicited spindle sequences made off by depolarizing waves giving rise to spike bursts. 3. Type II cells (n = 9) did not discharge spike bursts to large depolarizing current pulses even when the Vm reached -100 mV, nor did they fire rebound bursts after long-lasting hyperpolarizing current pulses or spike bursts riding on the rhythmic depolarizing components of spindle sequences. 4. Compared with type I cells, type II cells showed less frequency accommodation during tonic firing. The latter neuronal class discharged at high frequencies (40 Hz) with slight DC depolarization, approximately 8-10 Hz at the resting Vm, and no underlying synaptic or subthreshold oscillatory events could be detected when the firing was blocked by DC hyperpolarization. 5. The presence of two cell classes in the RE nucleus challenges the common view that this nucleus consists of a single neuronal class. We suggest that a different set of conductances is present in type II RE neurons, thus preventing the low-threshold Ca2+ current from dominating the behavior of these cells.     

Palatopharyngeal surgery. A study of its effectiveness in the treatment of obstructive apnea syndrome during sleep

Palatopharyngeal surgery is a therapeutic option for obstructive Sleep Apnea Syndrome (OSAS). This operation is based on the assumption that the soft palate is the principal apneogenic area of the upper airways. The effectiveness of palatopharyngeal surgery and of correcting nasal obstruction (co-adjuvant factor of SAOS), when present, was evaluated. Thirty patients were selected by cephalometry for surgery (3 women, 27 men; age 45.3 +/- 7.5 years). The success rate was 60%, which justifies the inclusion of surgery as a useful option for treating SAOS.     

Anatomic basis of continuous axillary block of the brachial plexus with thoracic reservoir

Although continuous axillary block is effective for periods of up to four to six weeks, pain clinic patients with severe chronic pain in the upper extremities, mainly resulting from neuropathic disease, can require continuous drug delivery by catheter-reservoir for up to three months or longer. We studied possible locations for implanting reservoirs or catheters from the perivascular axillary space in fresh cadavers, checking for possible vascular or nerve damage after applying the usual technique for reservoir implantation. The ideal location for the reservoir is the subcutaneous tissue of the homolateral infraclavicular space of the anterior side of the thorax. The customary procedures for inserting the catheter along the subcutaneous route that extends from the perivascular axillary space to the reservoir carry no risk of damaging vascular or nerve structures.     

Ophthalmoplegia-ataxia-areflexia in pediatrics. Three new patients and review of the literature

OBJECTIVE: The objective of this study was to investigate if pediatric patients with benign brainstem encephalitis (Bickerstaff Syndrome) or with Miller-Fisher Syndrome are the extremes of the same nosological entity which, in adults, has been named ophalmoplegia-ataxia-areflexia syndrome. PATIENTS AND METHODS: The subjects included in the study were three patients of our institution and 24 patients found in the revision of the English and Spanish pediatric literature who fulfilled the diagnostic criteria of ophtalmoplegia-ataxia-areflexia syndrome. The topographical location of the lesion in the nervous system was based on previously established criteria by using clinical and complementary studies. RESULTS: Of the 27 patients included in the study we were able to reach an accurate topographical diagnosis in 9. None had an exclusive involvement of the peripheral nervous system, (6) had exclusively central nervous system involvement and 2 showed involvement of both system. In 12, the topographical location of the lesion could be only ascertained as probable; 3 of them in the peripheral nervous system, 2 in the central nervous system and mixed involvement in 7. In the remaining 7 patients there were insufficient clinical data to allow topographical classification. CONCLUSIONS: The ophtalmoplegia-ataxia-areflexia syndrome can also be found in pediatric patients. The lesion in the majority of patients in this age group is located in the central nervous system, either alone or combined with peripheral nervous system involvement.     

Personal RF exposimetry in urban area

The purpose of the current study was to evaluate the usefulness of a radiofrequency (RF) personal exposimeter (dosimeter) for assessing individual RF exposure in an urban environment. Measurements taken by RF personal dosimeter were also compared to preliminary site measurements taken around mobile base stations. The results from personal exposure showed that one third of the participants spent 40–70% of 24 h recording time above the detection limits (0.05 V/m), and half of subjects spent less than 10%. The highest exposure was detected during the traveling period and the lowest in bed at home. Based on our results, we concluded that site measurements cannot be used to accurately determine personal exposure. We also concluded that duration of time exposed to RF levels above the detection limit of the personal dosimeter is a useful exposure metric to compare and contrast individual RF exposure of study subjects.     

Reinforcement of single-walled carbon nanotube bundles by intertube bridging

During their production, single-walled carbon nanotubes form bundles. Owing to the weak van der Waals interaction that holds them together in the bundle, the tubes can easily slide on each other, resulting in a shear modulus comparable to that of graphite. This low shear modulus is also a major obstacle in the fabrication of macroscopic fibres composed of carbon nanotubes. Here, we have introduced stable links between neighbouring carbon nanotubes within bundles, using moderate electron-beam irradiation inside a transmission electron microscope. Concurrent measurements of the mechanical properties using an atomic force microscope show a 30-fold increase of the bending modulus, due to the formation of stable crosslinks that effectively eliminate sliding between the nanotubes. Crosslinks were modelled using first-principles calculations, showing that interstitial carbon atoms formed during irradiation in addition to carboxyl groups, can independently lead to bridge formation between neighbouring nanotubes.