Single Beam Interferometry of a Thermal Bump: II—Theory

Kuo and Munidasa [1] have reported a method by which a time-dependent optical intensity pattern is produced by the interference of laser light diffracted from a thermally induced bump with the light of the same laser reflected from the plane of the sample on which the bump was induced. In their experiment the thermal bump was induced by a second laser beam which was optically incoherent with the interfering light, but which was intensity modulated at frequencies ranging from the audio to the ultrasonic range. The resulting time-dependent patterns carry information about the thermal and elastic properties of the sample. The purpose of this work is to provide a first-principles calculation of those patterns so that those material properties can be measured with this technique. The starting point of the calculation is the solution to the coupled thermoelastic equations developed by Favro et al. [2–4]. That solution is expressed in terms of the three eigenmodes of the coupled equations: (1) a longitudinal acoustic wave consisting of propagating particle displacements and associated temperature variations arising from the compression and rarefaction of the material; (2) a transverse (shear) wave which consists only of propagating particle displacements and which does not cause any temperature variation as it propagates; and (3) a heavily-damped thermal wave which consists of propagating temperature variations and associated particle displacements arising from the thermal expansion it causes. The combination of surface displacements (i.e. “thermal bump”) resulting from these three kinds of waves when a modulated laser beam is incident on the surface of an opaque solid can be calculated in a straight forward fashion from expressions given in [4]

Single Beam Interferometry of a Thermal Bump: I—Experiment

We present a sensitive interferometric technique which simultaneously measures the optical, elastic and thermal parameters of solids. We obtain the optical reflectivity change and the displacement due to thermal expansion (thermal bump) produced by an intensity modulated and focused laser beam

Clinical trial of a low-cost external fixator for global surgery use

PURPOSE: A low-cost modular external fixator for the lower limb has been developed for global surgery use. The purpose of this study is to assess outcome measures in the first clinical use of the device. METHODS: A prospective cohort study was conducted with patients recruited in two trauma hospitals. Initial clinical procedure data were collected, and patients were followed up every two weeks until 12 weeks or definitive fixation. Follow-up assessed infection, stability, and radiographic outcomes. In addition, patient-reported outcomes and surgeons' feedback on device usability were collected by questionnaires. RESULTS: The external fixator was used on 17 patients. Ten were mono-lateral, five were joint spanning, and two were delta configuration. One patient had a pin site infection at 12-week follow-up. All were stable when tested mechanically and using radiographic assessment, and 53% were converted to definitive fixation. CONCLUSION: The low-cost external fixator developed is appropriate for use in global surgery trauma centres with good clinical outcomes. PROSPECTIVE TRIAL REGISTRATION NUMBER AND DATE: SLCTR/2021/025 (06 Sep 2021)

Gene content evolution in the arthropods

Arthropods comprise the largest and most diverse phylum on Earth and play vital roles in nearly every ecosystem. Their diversity stems in part from variations on a conserved body plan, resulting from and recorded in adaptive changes in the genome. Dissection of the genomic record of sequence change enables broad questions regarding genome evolution to be addressed, even across hyper-diverse taxa within arthropods. Using 76 whole genome sequences representing 21 orders spanning more than 500 million years of arthropod evolution, we document changes in gene and protein domain content and provide temporal and phylogenetic context for interpreting these innovations. We identify many novel gene families that arose early in the evolution of arthropods and during the diversification of insects into modern orders. We reveal unexpected variation in patterns of DNA methylation across arthropods and examples of gene family and protein domain evolution coincident with the appearance of notable phenotypic and physiological adaptations such as flight, metamorphosis, sociality, and chemoperception. These analyses demonstrate how large-scale comparative genomics can provide broad new insights into the genotype to phenotype map and generate testable hypotheses about the evolution of animal diversity

The Drosophila melanogaster Genetic Reference Panel

A major challenge of biology is understanding the relationship between molecular genetic variation and variation in quantitative traits, including fitness. This relationship determines our ability to predict phenotypes from genotypes and to understand how evolutionary forces shape variation within and between species. Previous efforts to dissect the genotype-phenotype map were based on incomplete genotypic information. Here, we describe the Drosophila melanogaster Genetic Reference Panel (DGRP), a community resource for analysis of population genomics and quantitative traits. The DGRP consists of fully sequenced inbred lines derived from a natural population. Population genomic analyses reveal reduced polymorphism in centromeric autosomal regions and the X chromosome, evidence for positive and negative selection, and rapid evolution of the X chromosome. Many variants in novel genes, most at low frequency, are associated with quantitative traits and explain a large fraction of the phenotypic variance. The DGRP facilitates genotype-phenotype mapping using the power of Drosophila genetics

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

The Drosophila melanogaster Genetic Reference Panel

A major challenge of biology is understanding the relationship between molecular genetic variation and variation in quantitative traits, including fitness. This relationship determines our ability to predict phenotypes from genotypes and to understand how evolutionary forces shape variation within and between species. Previous efforts to dissect the genotype–phenotype map were based on incomplete genotypic information. Here, we describe the Drosophila melanogaster Genetic Reference Panel (DGRP), a community resource for analysis of population genomics and quantitative traits. The DGRP consists of fully sequenced inbred lines derived from a natural population. Population genomic analyses reveal reduced polymorphism in centromeric autosomal regions and the X chromosome, evidence for positive and negative selection, and rapid evolution of the X chromosome. Many variants in novel genes, most at low frequency, are associated with quantitative traits and explain a large fraction of the phenotypic variance. The DGRP facilitates genotype–phenotype mapping using the power of Drosophila genetics

Single Beam Interferometry of a Thermal Bump: II—Theory

Kuo and Munidasa [1] have reported a method by which a time-dependent optical intensity pattern is produced by the interference of laser light diffracted from a thermally induced bump with the light of the same laser reflected from the plane of the sample on which the bump was induced. In their experiment the thermal bump was induced by a second laser beam which was optically incoherent with the interfering light, but which was intensity modulated at frequencies ranging from the audio to the ultrasonic range. The resulting time-dependent patterns carry information about the thermal and elastic properties of the sample. The purpose of this work is to provide a first-principles calculation of those patterns so that those material properties can be measured with this technique. The starting point of the calculation is the solution to the coupled thermoelastic equations developed by Favro et al. [2–4]. That solution is expressed in terms of the three eigenmodes of the coupled equations: (1) a longitudinal acoustic wave consisting of propagating particle displacements and associated temperature variations arising from the compression and rarefaction of the material; (2) a transverse (shear) wave which consists only of propagating particle displacements and which does not cause any temperature variation as it propagates; and (3) a heavily-damped thermal wave which consists of propagating temperature variations and associated particle displacements arising from the thermal expansion it causes. The combination of surface displacements (i.e. “thermal bump”) resulting from these three kinds of waves when a modulated laser beam is incident on the surface of an opaque solid can be calculated in a straight forward fashion from expressions given in [4].</p

Single Beam Interferometry of a Thermal Bump: I—Experiment

We present a sensitive interferometric technique which simultaneously measures the optical, elastic and thermal parameters of solids. We obtain the optical reflectivity change and the displacement due to thermal expansion (thermal bump) produced by an intensity modulated and focused laser beam.</p