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Biomedical subjects

S Enoch

Publications and source records attributed to S Enoch.

13 recordsLinked to original sources
PubMed2006

Strong modification of the nonlinear optical response of metallic subwavelength hole arrays.

The influence of hole shape on the nonlinear optical properties of metallic subwavelength hole arrays is investigated. It is found that the amount of second harmonics generated can be enhanced by changing the hole shape. In part this increase is a direct result of the effect of hole shape on the linear transmission properties. Remarkably, in addition to enhancements that follow directly from the linear properties of the array, we find a hot hole shape. For rectangular holes the effective nonlinear response is enhanced by more than 1 order of magnitude for one particular aspect ratio. This enhancement can be attributed to slow propagation of the fundamental wavelength through the holes which occurs close to the hole cutoff.

Journal Article↗
PubMed2006

Automated QSPR through Competitive Workflow.

This paper describes a novel software architecture, Competitive Workflow, which implements workflow as a distributed and competitive multi-agent system. The implementation of a competitive workflow architecture designed to model important computer-aided molecular design workflows, the Discovery Bus, is described. QSPR modelling results for three example ADME datasets, for solubility, human plasma protein binding and P-glycoprotein substrates using an autonomous QSPR modelling workflow implemented on the Discovery Bus are presented. The autonomous QSPR system allows exhaustive exploration of descriptor and model space, automated model validation and continuous updating as new data and methods are made available. Prediction of properties of novel structures by an ensemble of models is also a feature of the system.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Distinct phenotype associated with a cryptic subtelomeric deletion of 19p13.3-pter.

Telomeres are gene rich regions with a high recombination rate. Cryptic subtelomeric rearrangements are estimated to account for 5% of mental retardation/malformation syndromes. Here we present the first patient with a deletion of 19p13.3, identified by subtelomeric FISH analysis. His features included a distinctive facial appearance, cleft palate, hearing impairment, congenital heart malformation, keloid scarring, immune dysregulation, and mild learning difficulties. Subtelomeric FISH analysis identified a deletion of 19p13.3-pter. The deletion size was determined to be 1.2 Mb by FISH analysis. It extended from within the chromosomal region covered by BAC RP11-50C6 to 19pter. The deleted area encompassed approximately 60 genes. Fifteen possible candidate genes were considered with respect to the phenotype, including follistatin-related precursor 3 (FSTL3) and serine-threonine kinase 11 (STK-11).

Abnormalities, Multiple↗
PubMed2005

Band gap formation and multiple scattering in photonic quasicrystals with a Penrose-type lattice.

This Letter presents a study of the local density of states (LDOS) in photonic quasicrystals. We show that the LDOS of a Penrose-type quasicrystal exhibits small additional band gaps. Among the band gaps, some exhibit a behavior similar to that typical of photonic crystals, while others do not. The development of certain band gaps requires large-size quasicrystals. It is explained by the long-range interactions involved in their formation. Moreover, the frequencies where the band gaps occur are not necessarily explained using single scattering and should therefore involve multiple scattering.

Journal Article↗
PubMed2005

Informed consent should be obtained from patients to use products (skin substitutes) and dressings containing biological material.

BACKGROUND: Biological products (tissue engineered skin, allograft and xenograft, and biological dressings) are widely used in the treatment of burns, chronic wounds, and other forms of acute injury. However, the religious and ethical issues, including consent, arising from their use have never been addressed in the medical literature. AIMS: This study was aimed to ascertain the views of religious leaders about the acceptability of biological products and to evaluate awareness among healthcare professionals about their constituents. METHODS: The religious groups that make up about 75% of the United Kingdom population were identified and a questionnaire on 11 biological products was sent to its leaders. Another questionnaire concerning 17 products (11 biological and 6 synthetic dressings) was sent to 100 healthcare professionals working in seven specialist units in the UK. RESULTS: All religious leaders (100% response rate) replied, some after consultation with international bodies. Among them, 77% said that patients should be informed of the constituents of the biological products and consent obtained. Some leaders expressed concerns about particular products including the transmission of viral and prion diseases, cruelty to animals, and material derived from neonates. None of the healthcare professionals (73% response rate) surveyed knew the constituents of all the products correctly. CONCLUSION: Ignoring religious sensitivities and neglecting consent in the usage of biological products could have very serious implications, including litigation. Hospitals and manufacturers should take immediate measures to enlighten healthcare professionals of the constituents of these products so that they can obtain informed consent from patients.

Attitude to Health↗
PubMed2004

Strong influence of hole shape on extraordinary transmission through periodic arrays of subwavelength holes.

We show that extraordinary light transmission of periodic subwavelength hole arrays, generally attributed to surface-plasmon resonances, is strongly influenced by the hole shape. Both experiments and calculations, based on a Fourier modal method, demonstrate that a shape change from circular to rectangular increases the normalized transmission by an order of magnitude while the hole area decreases. Moreover, the spectra exhibit large redshifts (approximately 2500 cm(-1)). A comparison with the transmission of isolated holes shows that shape resonances of the rectangular holes play a dominant role.

Journal Article↗
PubMed2003

Thromboprophylaxis can be omitted in selected patients undergoing varicose vein surgery and hernia repair.

BACKGROUND: There is no current agreement on the routine use of thromboprophylaxis in patients undergoing varicose vein surgery and hernia repair. In the authors' hospital, prophylaxis is given only to those considered to be at an increased risk. A retrospective review was conducted to determine whether it was safe to omit prophylaxis in low-risk patients. METHODS: Data were extracted from the hospital database about all patients who underwent the above procedures between January 1997 and December 2001. The case notes of patients who developed venous thromboembolism (VTE) within 3 months of surgery were reviewed. The pharmacy database was then analysed to determine the effect of prophylaxis. RESULTS: A total of 4670 patients were identified. Some 2186 patients had varicose vein surgery; 1283 patients received prophylaxis, of whom four developed VTE. None of the 903 patients who did not receive prophylaxis developed VTE. A total of 2484 patients had hernia repair, of whom 1854 patients received prophylaxis and 630 did not; one patient from each group developed VTE. CONCLUSION: Low-risk patients having hernia and vein surgery do not need thromboprophylaxis.

Adolescent↗
PubMed2000

Anomalous refractive properties of photonic crystals

We describe methods of investigating the behavior of photonic crystals. Our approach establishes a link between the dispersion relation of the Bloch modes for an infinite crystal (which describes the intrinsic properties of the photonic crystal in the absence of an incident field) and the diffraction problem of a grating (finite photonic crystal) illuminated by an incident field. We point out the relationship between the translation operator of the first problem and the transfer matrix of the second. The eigenvalues of the transfer matrix contain information about the dispersion relation. This approach enables us to answer questions such as When does ultrarefraction occur? Can the photonic crystal simulate a homogeneous and isotropic material with low effective index? This approach also enables us to determine suitable parameters to obtain ultrarefractive or negative refraction properties and to design optical devices such as highly dispersive microprisms and ultrarefractive microlenses. Rigorous computations add a quantitative aspect and demonstrate the relevance of our approach.

Journal Article↗