Theoretical Estimation of Thermal Effects in Drilling of Woven Carbon Fiber Composite

Carbon Fiber Reinforced Polymer (CFRPs) composites are extensively used in structural applications due to their attractive properties. Although the components are usually made near net shape, machining processes are needed to achieve dimensional tolerance and assembly requirements. Drilling is a common operation required for further mechanical joining of the components. CFRPs are vulnerable to processing induced damage; mainly delamination, fiber pull-out, and thermal degradation, drilling induced defects being one of the main causes of component rejection during manufacturing processes. Despite the importance of analyzing thermal phenomena involved in the machining of composites, only few authors have focused their attention on this problem, most of them using an experimental approach. The temperature at the workpiece could affect surface quality of the component and its measurement during processing is difficult. The estimation of the amount of heat generated during drilling is important; however, numerical modeling of drilling processes involves a high computational cost. This paper presents a combined approach to thermal analysis of composite drilling, using both an analytical estimation of heat generated during drilling and numerical modeling for heat propagation. Promising results for indirect detection of risk of thermal damage, through the measurement of thrust force and cutting torque, are obtained.     

Myeloid-derived suppressor cells limit the inflammation by promoting T lymphocyte apoptosis in the spinal cord of a murine model of multiple sclerosis

Multiple Sclerosis (MS) is a demyelinating/inflammatory disease of the central nervous system. Relapsing-remitting MS is characterized by a relapsing phase with clinical symptoms and the production of inflammatory cell infiltrates, and a period of remission during which patients recover partially. Myeloid-derived suppressor cells (MDSCs) are immature cells capable of suppressing the inflammatory response through Arginase-I (Arg-I) activity, among other mechanisms. Here, we have identified Arg-I(+) -MDSCs in the spinal cord during experimental autoimmune encephalomyelitis (EAE), cells that were largely restricted to the demyelinating plaque and that always exhibited the characteristic MDSC surface markers Arg-I/CD11b/Gr-1/M-CSF1R. The presence and density of Arg-I(+) -cells, and the proportion of apoptotic but not proliferative T cells, were correlated with the EAE time course: peaked in parallel with the clinical score, decreased significantly during the remitting phase and completely disappeared during the chronic phase. Spinal cord-isolated MDSCs of EAE animals augmented the cell death when co-cultured with stimulated control splenic CD3 T cells. These data point to an important role for MDSCs in limiting inflammatory damage in MS, favoring the relative recovery in the remitting phase of the disease. Thus, the MDSC population should be considered as a potential therapeutic target to accelerate the recovery of MS patients.     

Pessimistic attributions and coping strategies as predictors of depressive symptoms in people with coronary heart disease

This two-wave longitudinal study examines the ability of pessimistic attributional style and coping strategies to predict depressive symptoms in a sample of 99 patients with coronary heart disease (CHD). After the cardiac episode, the globality dimension of this style was associated with increased depressive symptoms, and this association was mediated by the low use of effective coping strategies. Stability and globality dimensions of pessimistic attributional style could also predict depressive symptoms eight weeks later. Cardiac intervention programmes should include the treatment of these symptoms and promote effective coping strategies as well as the modification of these stable and global attributions.     

Optical coherence tomography in central retinal artery occlusion

CLINICAL CASES: Three eyes with central retinal artery occlusion (CRAO) have been studied. Optical coherence tomography (OCT) was performed in each of them. Ophthalmoscopic signs of CRAO were equivocal in the three eyes. However, the presence of a hyporeflective signal in the OCT scan could be seen clearly in each of them. DISCUSSION: The presence of a hyporeflective band between the neurosensory retina and the retinal pigment epithelium in OCT images, that persist for several months after a CRAO episode, is useful in establishing the diagnosis in these patients.     

Two cases of leprosy in Valladolid

Leprosy is still a major health problem on a worldwide level, and although it does not reach endemic levels on our continent, it seems that there is an upward trend due to the number of imported cases diagnosed each year. We present two cases of lepromatous leprosy diagnosed in Valladolid within a five-month period. The last reported case of this disease in our community was over 20 years ago.     

Intraocular lens opacification after nonpenetrating glaucoma surgery with mitomycin-C

A 58-year-old woman had successful phacoemulsification with intraocular lens (IOL) implantation in January 2001. Two years later, nonpenetrating glaucoma surgery with mitomycin-C (MMC) 0.02% was performed for uncontrolled glaucoma. Two months later, opacification of the anterior IOL surface was observed. The IOL was removed and a hydrophobic acrylic AcrySof IOL (Alcon) implanted. The opacified IOL was studied by flame atomic absorption spectrometry, which showed the presence of calcium carbonate. A new IOL of the same model was placed in an aqueous solution with calcium carbonate and basic pH, and the same opacification developed. We hypothesize that the change in aqueous humor pH after glaucoma surgery and the characteristics of the IOL precipitated deposition of calcium.