Photopolymer Holographic Lenses for Solar Energy Applications: A Review.

Holographic lenses (HLs) are part of holographic optical elements (HOE), and are being applied to concentrate solar energy on a focal point or focal line. In this way, the concentrated energy can be converted into electrical or thermal energy by means of a photovoltaic cell or a thermal absorber tube. HLs are able to passively track the apparent motion of the sun with a high acceptance angle, allowing tracking motors to be replaced, thus reducing the cost of support structures.

Holographic Lens Resolution Using the Convolution Theorem.

The similarity between object and image of negative asymmetrical holographic lenses (HLs) stored in a low-toxicity photopolymer has been evaluated theoretically and experimentally. Asymmetrical experimental setups with negative focal lengths have been used to obtain HLs. For this purpose, the resolution of the HLs was calculated using the convolution theorem.

Green and wide acceptance angle solar concentrators.

A low-toxicity photopolymer was employed to prepare holographic solar concentrators (HSCs). The main aim of this study is to obtain a versatile holographic element to concentrate the sunlight from different relative positions of the Sun during the day, avoiding the need of expensive tracking systems. Multiplexed holographic elements that combine symmetric and asymmetric holographic lenses of low frequency (545 l/mm) have been recorded in the same plate to concentrate the sunlight from sunrise to sunset.

Aberration-Based Quality Metrics in Holographic Lenses.

Aberrations and the image quality of holographic lenses were evaluated by a Hartmann-Shack (HS) wavefront sensor. Two lenses, one recorded with a symmetrical configuration and the other with an asymmetrical one, were stored in a photopolymer called Biophotopol. Each was reconstructed with two different wavelengths, 473 nm and 633 nm.

Holographic Lenses in an Environment-Friendly Photopolymer.

In this paper, we theoretically and experimentally evaluated the quality of volume phase transmission lenses stored in an environmentally friendly photopolymer. Holographic lenses (HLs) were obtained using symmetrical and asymmetrical experimental setups with the same positive and negative focal length and pupil diameter. The image quality was evaluated from the calculation of the modulation transfer function (MTF) by capturing the point spread function (PSF) with a charge-coupled device (CCD).

Survival of patients with chronic respiratory failure on long-term oxygen therapy and or non-invasive ventilation at home.

Background & Aims: Chronic respiratory failure (CRF) is the common fate of respiratory diseases where systemic effects contribute to outcomes. In a prospective cohort of home-treated patients with CRF, we looked for predictors of long-term survival including respiratory, nutritional and inflammatory dimensions.

Methods: 637 stable outpatients with CRF, 397 men, 68 ± 11 years, on long-term oxygen therapy and/or non-invasive ventilation from 21 chest clinics were enrolled and followed over 53 ± 31 months.

Management of tracheobronchial amyloidosis with therapeutic bronchoscopic techniques.

Amyloidosis is a systemic disease caused by abnormal deposition of amyloid material that is detected with Congo red staining and is difficult to diagnose. Involvement of the tracheobronchial tree is rare and is a challenge for pulmonologists because of the wide differential diagnosis of this disease. We present two cases where tracheobronchial affectation has been observed: in one of them as a primary disease, and in another as secondary affectation.

Directly observed treatment for tuberculosis in pharmacies compared with self-administered therapy in Spain.

Objectives: To compare directly observed treatment (DOT) of tuberculosis through pharmacy offices with self-administered treatment (SAT) in patients at risk for non-adherence.

Methods: Prospective study for DOT (1999-2002) and retrospective study for SAT (1996-1998) in patients at risk for non-adherence (human immunodeficiency virus [HIV] infection, alcoholism, illicit drug use, immigrant or homeless status and/or previous failure to complete). Patients in the DOT programme received medication as out-patients twice a week in pharmacies that supervised adherence and provided socio-sanitary support to patients.

[Lethal nemalinic myopathy and congenital arthrogryposis].

Introduction: Nemalinic myopathy (NM) is a non progressive congenital disorder of skeletal muscle, characterized by rod like formations present in muscle fibres, whilst congenital multiple arthrogryposis (CMA) is a syndrome characterized by contractures and articular rigidity which may be due to many causes, including NM.

Clinical Case: A boy of 0 h of premature life, with CMA was assessed on the suspicion of neuromuscular disease with normal preliminary studies. Muscle biopsy eventually showed the typical rod like formations of NM.

Magnetic resonance imaging of the pharynx in OSA patients and healthy subjects.

Obstructive sleep apnoea (OSA) occurs because of recurrent narrowing and occlusion of the velopharynx (VP) during sleep. The specific cause of OSA is unknown. Cephalometric radiography, fibreoptic nasopharyngoscopy, acoustic reflection techniques, and computerized tomography have limitations (dynamic and tridimensional evaluation) in the mechanism of occlusion investigation.

[Acute respiratory insufficiency as initial manifestation of brain stem lesions].

We describe three patients with different brainstem lesions (bulbar angioma, bulbar infarct, and Arnold-Chiari malformation) who debuted with acute respiratory insufficiency. Other neurological manifestations had gone unobserved in all three cases. Respiratory insufficiency worsened notably during sleep to the point that mechanical ventilation was required or death occurred (Ondine s curse).