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7 pags., 4 figs., 1 tab., Available experimental neutron skin thicknesses of even-even stable Ca, Ni, Sn, Pb, and Cd isotopes are evaluated, and separate trends of neutron skin thickness versus relative neutron excess δ=(N-Z)/A are observed for different isotopic chains. This phenomenon is quantitatively reproduced by the deformed Skyrme Hartree-Fock + Bardeen-Cooper-Schrieffer model with SLy4 force., This work is supported in part by the NSFC (12022504, 11775273, U1932140,12121005), by the CAS Pioneer Hundred Talents Program, by the CAS Open Research Project of large research infrastructures, by the CAS Maintenance and Reform of Large Research Infrastructures (DSS-WXGZ2018-0002), and by the Max Plank Society. Y.A.L. acknowledges the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 682841 “ASTRUm”) and P.S. acknowledges MCI/AEI/FEDER, UE (Spain) (Grant no. PGC2018-093636-B-I00)

This paper reports the linear frequency-modulated thermography inspection of disbonds in titanium alloy honeycomb sandwich structures with different skin thicknesses. A three-dimensional finite element model of a titanium alloy honeycomb sandwich structure is built. The maximum value of the phase difference between the disbond defect region and the nondefective region is used to optimize the heating duration and frequency bandwidth. Three titanium alloy honeycomb sandwich structure specimens, with a skin thickness of 0.6 mm, 0.85 mm, and 1.2 mm, respectively, are manufactured, in which skin-to-core disbond defects are prepared. The linear frequency-modulated thermography experiments are carried out on the specimens. The correlation algorithm is used to process the infrared image sequences. The experimental results show that linear frequency-modulated thermography can realize the fast and efficient inspection of the disbonds in titanium alloy honeycomb sandwich structures with different skin thicknesses. For skin thickness ranges from 0.6 mm to 1.2 mm, a heating duration of 22 s and a frequency range of 0.01 Hz–0.21 Hz are recommended.

In this chapter, experimental investigations into the boundary layer and the mechanical characteristics of dolphin skin are performed, and variants mechanical models of dolphin skin are proposed. A device for measuring the mechanical characteristics of the skin of living dolphins is described. Experimental investigations into the skin elasticity of various types of living dolphins are carried out. The distribution of skin elasticity over the body of dolphins at different swimming speeds is described. The selected sizes of mass, density, and coefficient of the oscillating mass of individual dolphin skin layers are experimentally determined. The distribution of the thickness of the laminar and turbulent boundary layers along the body is compared with the distribution of dolphin skin thicknesses along the body. The parameters of the limiting frequency, tension, and dampening are also determined. Experimental investigations of the speed of propagation and dampening of forced oscillations on the skin surface of a living dolphin.

This article considers a previously overlooked feature in carbon molecular sieve (CMS) membranes that we term a “hyperskin” present at the outermost region of dense CMS selective layers. Such a feature with much lower permeability, but similar selectivity compared to the bulk of the skin, reduces CMS hollow fiber permeance below that predicted from corresponding dense films. Effects of the hyperskin are considered for CMS hollow fibers with low skin thicknesses based on two polyimide precursors – Matrimid® and 6FDA:BPDA-DAM. Although the fundamental formation mechanism for the hyperskin feature suggests its existence on virtually all CMS membranes, its impact on transport properties is shown to differ dramatically, depending on the detailed characteristic properties of the specific CMS membrane. Indeed, for hollow fibers with very low nominal resistance (i.e. Selective layer thickness determined by SEM Intrinsic permeability of thick dense CMS films ), the observed permeance only reaches a small fraction of the predicted permeance. The selectivity between different gas penetrants, however, is not altered by the presence of this hyperskin. While identifying this issue is the major focus of this article, strategies to address this limitation, without compromising the molecular sieving properties of CMS membranes are briefly discussed.

Electromechanical impedance (EMI) method is one of the most widely used structural health monitoring (SHM) methods. The low-cost alternative of the method, surface response to excitation (SuRE) method has the similar characteristics. Both methods require additional disks/sensors to estimate the location of defects or external loading. Additive manufacturing (AM) methods have been matured and started to be an alternative to the conventional manufacturing. Most of the parts made by the AM methods are hollow. The infill type and skin thickness are selected to manufacture the parts faster by using less material and to avoid warping of the part. In this paper, manufacture of the parts with two infill types and two surface skin thicknesses at their different locations are proposed to estimate the site of the applied external forces without using additional disks/sensors. SuRE method was used in the study. The experimental results indicated that the frequencies of the most changed spectrum sections were different depending on the infill types and surface skin thicknesses. The same approach could be used for the EMI applications.

The rationale of this study is to perform a personalized dosimetry in digital mammography, using Monte Carlo simulations. We developed a GEANT4-based application that reproduces mammographic investigations editable in different setups and conditions. Mean Glandular Dose (MGD) is estimated for different compressed breast sizes and compositions. Breast compositions are obtained with homogeneous mixture of glandular and adipose tissues. The simulated setup reproduces the Hologic Selenia® Dimensions® Mammography System and the TASMIPM tool for deriving the photon fluence from the X-ray source has been employed. The influence of different skin models is also investigated, deriving the mean glandular dose in the breast using adipose tissue for different skin thicknesses, from 2 mm to 5 mm, and a dedicated composition found in literature with the specific thickness of 1.45 mm. We denoted different photon shielding properties on the MGD values.

We used the cluster structure properties of the 212Po to estimate the neutron skin thickness of 208Pb. For this purpose, we considered two important components: (a) alpha decay is a low energy phenomenon; therefore, one can expect that the mean-field, which can explain the ground state properties of 212Po, does not change during the alpha decay process. (b) 212Po has a high alpha cluster-like structure, two protons and two neutrons outside its core nucleus with a double magic closed-shell, and the cluster model is a powerful formalism for the estimation of alpha decay preformation factor of such nuclei. The slope of the symmetry energy of 208Pb is estimated to be MeV within the selected same mean-fields and Skyrme forces, which can simultaneously satisfy the ground-state properties of parent and daughter nuclei, as their neutron skin thicknesses are consistent with experimental data.

The change of proton and neutron skin thicknesses is investigated in nuclei after \ensuremath{\alpha} decay. The skin thicknesses are self-consistently calculated. The observed \ensuremath{\alpha} decays lead to relatively large decrease of the proton skin in the daughter nuclei. A large increase of the neutron skin in the daughter nucleus reflects the hindered \ensuremath{\alpha} decay. This hindrance is related to the decrease of both the ${Q}_{\ensuremath{\alpha}}$ value and the preformation probability in the parent nucleus. For each isotopic chain, the observed half-lives consistently correlate with the change of the proton (neutron) skin thickness, from parent to daughter nuclei.

Within the density-dependent cluster model (DDCM), the decay half-lives of 22 cluster emitters are calculated by using experimental decay energies. Based on our previous study on cluster radioactivity [Phys. Rev. C 90, 064310 (2014)], not only the quadratic symmetry energy ${E}_{2}({\ensuremath{\rho}}_{0})$ and its slope ${L}_{2}({\ensuremath{\rho}}_{0})$ but also the quartic symmetry energy ${E}_{4}({\ensuremath{\rho}}_{0})$ and its slope ${L}_{4}({\ensuremath{\rho}}_{0})$ at the saturation density ${\ensuremath{\rho}}_{0}$ are constrained by considering the neutron skin thicknesses in the daughter nuclei. With the extracted values of ${E}_{2}({\ensuremath{\rho}}_{0})$ and ${L}_{2}({\ensuremath{\rho}}_{0})$, the exponent $\ensuremath{\gamma}$ of the quadratic density-dependent symmetry energy ${E}_{2}(\ensuremath{\rho})={E}_{2}({\ensuremath{\rho}}_{0}){(\ensuremath{\rho}/{\ensuremath{\rho}}_{0})}^{\ensuremath{\gamma}}$ is estimated. Moreover, the symmetry energy coefficient of nuclei ${a}_{\mathrm{sym}}(A)$ and the ratio $\ensuremath{\kappa}$ of the surface symmetry coefficient to the volume symmetry coefficient are extracted as well.

To restrict debonding, carbon fiber reinforced lattice-core sandwich composites with compliant skins were designed and manufactured. Compression behaviors of the lattice composites and sandwich columns with different skin thicknesses were tested. Bending performances of the sandwich panels were explored by three-point bending experiments. Two typical failure mechanisms of the lattice-core sandwich structures, delaminating and local buckling were revealed by the experiments. Failure criteria were suggested and gave consistent analytical predictions. For panels with stiff skins, delamination is the dominant failure style. Cell dimensions, fracture toughness of the adhesives and the strength of the sandwich skin decide the critical load capacity of the lattice-core sandwich structure. The mono-cell buckling and the succeeding local buckling are dominant for the sandwich structures with more compliant skin sheets. Debonding is restricted within one cell in bending and two cells in compression for lattice-core sandwich panels with compliant face sheets and softer lattice cores.

Although spatial summation of pain (SSP) is central to the processing of pain intensity and quality, its mechanism is not fully understood. We previously found greater heat SSP in hairy than in glabrous skin, suggesting that perhaps A-mechano-heat II (AMH-II) nociceptors are the dominant subserving system. In order to further explore the role of A-delta fibers in heat-induced SSP, we analyzed the electrophysiological correlates of SSP under conditions that minimize the influence of skin thicknesses. Among 17 subjects, fast rate of rise (70 °C/sec) heat stimuli that induced a pre-fixed, similar, SSP magnitude for hairy and glabrous skin were repeatedly administered using large and small probes, during which time the contact heat-evoked potentials (CHEPs) and pain ratings were recorded. Both N2 and P2 amplitudes were larger in hairy than in glabrous skin, but a differential effect of SSP was found on the CHEPs. Despite similar psychophysical SSP in hairy and glabrous skin, the electrophysiological SSP reflected in N2 but not P2 amplitude was larger in hairy skin. Nevertheless, regardless of skin type, SSP was manifested by an increase in P2 amplitudes. Considering the uniform psychophysical SSP for the two skin types, the fast stimulation rate and lower activity of AMH-II in glabrous skin, a greater electrophysiological SSP in hairy than in glabrous skin may suggest that SSP is mainly subserved by AMH nociceptors. The overall SSP effect, manifested in greater P2 amplitude, may reflect specific brain responses aimed to prepare the individual to an increased potential tissue damage.

Analysis of contaminant transport through fractured crystalline rocks has received considerable attention, particularly with regard to subsurface nuclear waste repositories. Most of the studies have employed the dual continuum approach, with the fractures and the rock matrix as the two continuums, assuming that fractures control the overall conductivity of the rock and the porous matrix just provides storage. However, field observations of rock fractures have shown that the real situation can be very complex. Based on some recent investigations, it has been reported that the portion of the rock matrix adjacent to many open fractures is physically and chemically altered. These alterations, referred to as the fracture skin, can have different sorption and diffusion properties compared to those of the undisturbed rock matrix and this may influence the transport of solutes through such formations. In the present study, a numerical model is developed to simulate conservative solute transport in a fractured crystalline rock formation using the triple continuum approach — with the fracture, fracture skin and the rock matrix as the three continuums. The model is solved using a fully implicit finite difference scheme. Contaminant migration in the fractured formation with and without skin has been simulated. It is observed that contaminant penetration along the fracture is enhanced at large flow velocities. The effect of flow velocity on conservative solute transport is investigated for different fracture apertures and fracture skin thicknesses. The influence of flow velocity on contaminant transport is demonstrated to be more with change in fracture aperture than with change in skin thickness.

Introduction: Although it is important to know the normal values of dermis, epidermis, or total skin thicknesses (ST) for some drugs and vaccine research, skin‑related clinical investigations, and skin transfer operations used in plastic surgery, it would not be ethical to take new biopsies from healthy volunteers to measure their ST. This study aims to describe a new ethical histometric technique for the measurement of skin layers and to determine the mean ST of some major body regions in the people living in our region. Materials and Methods: A total of 180 skin samples from six major body regions of 90 males and 90 females were enrolled in the study. The measurements were performed histometrically from appropriate skin samples obtained from the pathology archive. The samples were classified according to the six different parts of the body (scalp, abdomen, back, dorsum of foot, dorsum of hand, and the breast). Results: The mean epidermal thickness ranged from 76.9 ± 26.2 to 267.4 ± 120.6 μm. The thickest epidermis was found in the dorsum of foot in women (267.4 ± 120.6 μm) while the thinnest was found in the breast in women (76.9 ± 26.2 μm). The mean dermal thickness ranged from 2115 ± 946.4 to 5888 ± 2422.3 μm. The thickest dermis was found in the breast in men (5888 ± 2422.3 μm), while the thinnest dermis was found in the dorsum of hand in women (2115 ± 946.4 μm). Conclusions: Human ST varies according to ethnic origin. It was determined that the dermis and epidermis of Anatolian people are thicker than that of the previously reported other ethnic groups. The skin pathology archive can be used to create maps of the body’s skin structure. Keywords: Dermis, epidermis, histometric, skin thickness

This article reviews the current state of the art in the design of traditional uni-directional fibre laminate construction; beyond the ubiquitous balanced and symmetric design. A ply termination algorithm is then employed to develop permissible tapered designs, with single-ply terminations and ply contiguity constraints, which are free from undesirable changes in mechanical coupling characteristics. More importantly however, is the fact that all tapered designs have immunity to thermal warping distortion; which include all combinations of anti-symmetric (or cross-symmetric), non-symmetric and symmetric angle- and cross-ply sub-sequence symmetries. Tapered designs are presented for laminates with fully uncoupled properties, and those possessing extension–shearing and/or bending–twisting coupling. Such designs represent typical fuselage skin thicknesses, i.e., with between (n =) 12 and 16 plies, but due consideration is also given to new fuselage design concepts with grid-stiffeners and/or geodesic stiffener arrangements, for which thinner designs (n ⩾ 8) are of interest.

The total charge-changing, charge pick-up, and partial charge-changing cross sections of very neutron-rich nuclei (Ne-30, Na-32,Na-33) with a proton target have been measured at similar to 240A MeV for the first time. We introduced the phenomenological correction factor in Glauber-model calculations for the total charge-changing cross sections with the proton target, and applied it to deduce the proton radii of these nuclei. For 30Ne and Na-32, the neutron skin thicknesses of the nuclei were deduced by comparing the proton radii with the matter radii deduced from the interaction cross-section measurements. A significant thick neutron-skin has been observed for the nuclei. We also found that the charge pick-up cross sections are much larger than those in the systematics of stable nuclei.

Trenbolone acetate was experimentally fed to part of Atlantic salmon Salmo salar over 30 d at various dose levels. Skin thicknesses (epidermis and stratum compactum) were measured histologically at the end of the feeding trial. Fish from each feeding group were then given bath challenges of Aeromonas salmonicida to assess the effects of trenbolone acetate on susceptibility of the fish to bacterial disease. Epidermal thickness increased with the highest dose of trenbolone acetate fed but this provided no demonstrably greater protection against A. salmonicida.

In this era of competent materials and fabrication for air filtration the factor dictating the protection factor (ratio of concentration outside to inside the respirator) is unfiltered inward leakage. Respirator testing using humans is constrained by the requirement for advance approval of the protocol by a human use committee, by the diversity and caprices of the subjects used in testing, by factors such as fatigue and illness, and by health hazards of aerosol challenges. Hanson Robotics has designed and built a robotic headform with dimensions matching those of the medium headform identified from a NIOSH wearers panel. The polyurethane skull form and polydimethylsiloxane artificial skin covering (Frubber) also accurately reproduce skin thicknesses measured for a panel of male Caucasians aged 19 -22 and provide a good simulation of the gross surface texture of human skin and its elastic response to touch. An initial static test of fit of seven models of N95 respirators to a static prototype prepared from similar materials in the same dimensions showed a typical scatter of measured fit factors (FFs) after donning, and an average FF of slightly more than 200 in a second series of donnings in which a leak check was used to exclude samples for which FF was 100, showing that the headform does closely resemble a human head in the NIOSH medium size window. Statistical validation that this similarity constitutes functional equivalence is underway.

Yorkshire and Yucatan Mini-pig breeds have been commonly used for laser-tissue studies. The newer Yucatan Micro-pig breed has not been used in laser-tissue studies, but could be an alternative to meet logistical needs for laser-tissue studies if its skin is comparable to the accepted Yorkshire and Yucatan Mini-pig breeds. This study sought to contrast the differences in skin thickness and melanin content in pig skin across domestic swine breeds. Skin thickness was measured using HE eight Yorkshire pigs, two Yucatan Mini-pigs, and one Yucatan Micro-pig. Statistically significant intra-breed variations in the thicknesses of the stratum corneum, epidermis and dermis were found between equivalent sample sizes in the Yorkshire group. The Yucatan Micro-pig was found to have skin thicknesses more similar to the Yucatan Mini-pig?s compared to the Yorkshire. Results for the melanin index values indicate that the Yorkshire pig breed is most likely to have an average melanin index near 0.37%, with the Yucatan Mini- and Micro-pigs trending towards melanin index values greater than that of the Yorkshire pig breed. The sample sizes for the Mini- and Micro-pigs were insufficient to assess the complete melanin index values between breeds. Though this is not an equivalent sample size comparison, results indicate that the skin thickness and melanin distribution in the new Micro-pig are more similar to the Yucatan Mini-pig and not the Yorkshire breed, suggesting the Micro-pig may be a suitable substitute for experiments which have traditionally used the Mini-pig.

The density dependence of nuclear symmetry energy remains poorly constrained. Starting from precise empirical values of the nuclear volume and surface symmetry energy coefficients and the nuclear saturation density, we show how in the ambit of microscopic calculations with different energy density functionals, the value of the symmetry energy slope parameter $L$ alongwith that for neutron skin can be put in tighter bounds. The value of $L$ is found to be $L$= 64$\pm $5 MeV. For $^{208}$Pb, the neutron skin thickness comes out to be 0.188 $\pm $0.014 fm. Knowing $L$, the method can be applied to predict neutron skins of other nuclei., Comment: 5 pages, Phys. Rev. Lett. (accpeted)

As a non-invasive method, ultrasound is a suitable diagnostic procedure for routine in vivo examination of the human skin in dermatology. In this study 40 healthy test subjects were examined with a 20-MHz ultrasound scanner in order to determine the thickness and morphology of normal skin at 51 different sites. B-mode ultrasonography permits us to measure both the individual layers of the skin and deeper structures and to assess their definition and echogenicity. In both sexes the greatest skin thicknesses were found on: the shoulder-blade (mean thicknesses (mm), males 3.07/ females 2.47); the upper back (m, 3.04/f, 2.85); the chin (m, 3.04/f, 2.69); the lower lip (m, 2.66/f,2.50) and in the region of the lower back (m, 2.64/f, 2.39). Particularly thin skin was found on: the upper eyelid (m, 0.59/f, 0.64); the lower eyelid (m, 0.99/f, 0.86); in the groin (m. 0.97/f, 0.90); in the armpit (m, 1.01/f, 1.09) and on the forearm (m, 1.13/f. 1.00 mm). Knowledge of differences in the characteristic reflex patterns depending on the sex and age of the subject and the site of the skin examined forms the basis for assessment of pathological sonograms.

The effects of disbond (delamination) sizes and skin thicknesses on the dynamic response of honeycomb structures were investigated. A mechanical impedance instrument (MIA 3000) was used to test the specimens which were made of two layers of thin aluminium skins with Nomex honeycomb cores. Firstly, this study concentrated on the influence of disbond size on its resonance frequency and the amplitude and phase of impedance in honeycomb structures. Secondly, the influences of skin and honeycomb core thicknesses on these parameters were also investigated. It was found that, having the same skin thicknesses and materials, the resonance frequency of a large disbond was lower than that of a small disbond, and also lower than that of a good area. With a thicker skin, the resonance frequency was higher than that of a thinner skin. It was also observed that, with a thicker honeycomb core, the resonance frequency in a good area was larger than in that of a thinner one. The resonance frequency in a constant disbond, however, was invariant when the skin thicknesses and materials were kept the same. It was further evident that, with a swept frequency ranging from 1 to 8 kHz, most disbonds could be detected if the thicknesses of aluminium skin were between 0.5 and 2.0 mm.

Thick neutron skins (∼ 0.9 fm) have been verified for the first time in 6He and 8He nuclei from a combined analysis of the interaction and the fragmentation cross sections of 4,6,8He incident reactions at 800A MeV. A relativistic mean field (RMF) model was applied to 6He and 8He nuclei and shown to reproduce the neutron skin thicknesses very well. It is also shown that the RMF model predicts a gross linear dependence of the neutron skin thickness on the difference between the proton and the neutron Fermi energy in a wide range of nuclei. Possible observations of thick neutron skins in other nuclei, in particular in Na isotopes, are also discussed.

The ability of steel-concrete-steel sandwich tubes to resist local lateral loads has been investigated experimentally. Two types of loading were employed: quasi-static, by means of a 12.7 mm diameter hemispherically tipped punch, and dynamic, by means of a 12.7 mm diameter hemispherically tipped projectile fired from a compressed air gun. The performance of tubes with skin thicknesses of 1 mm and filler thicknesses of 10, 20 and 38 mm was measured in terms of energy absorption capabilities and compared with the equivalent performance of monolithic steel tubes.

Proton and neutron density profiles of 760 nuclei in the mass region of A=16-304are analyzed using the Skyrme energy density for the parameter set SLy4. Simple formulae are obtained to fit the resulting radii and diffuseness data. These formulae may be useful to estimate the values of the unmeasured radii, and especially in extrapolating charge radius values for nuclei which are far from the valley of stability or to perform analytic calculations for bound and/or scattering problems. The obtained neutron and proton root-mean-square radii and the neutron skin thicknesses are in agreement with the available experimental data., Comment: 14 pages,5 figures. arXiv admin note: text overlap with arXiv:1003.5225 by other authors

Objective To describe the interdomal fat pad, an important anatomical structure that, to our knowledge, has not been reported in the rhinoplasty literature. Design Anatomical observations were made during a consecutive series of external rhinoplasties, and the existence of the interdomal fat pad was documented in patients with noses of varying nasal skin thicknesses. Setting Private facial plastic surgery practice. Patients One hundred consecutive white patients undergoing external rhinoplasty were analyzed. Thirty-seven patients were undergoing secondary rhinoplasty and were excluded. Sixty-three patients undergoing primary rhinoplasty were enrolled into the study. Intervention None. Main Outcome Measures The nasal skin type of each patient was subjectively determined preoperatively to be thin, average, or thick. The presence or absence of a distinct fat pad between the domes of the lower lateral cartilages was observed and recorded in each group of patients. Results Among the 63 patients studied, 22 had thick skin; 31, average skin; and 10, thin skin. Well-defined interdomal fat pads were noted in 12 patients with thick skin, 13 patients with average skin, and 2 patients with thin skin. Conclusions There is a distinct anatomical structure that we refer to as the interdomal fat pad that exists in noses of all skin types. The awareness of this structure should encourage a careful and direct examination of the undersurface of nasal tip skin. An unrecognized, extensive fat pad may interfere with tip narrowing and refinement. It may be the cause of persistent postrhinoplasty supratip fullness and excessive tip width.

To extend the utility of normalized glandular dose (DgN) calculations to higher x-ray energies (up to 120 keV) and to provide the tools for investigators to calculate DgN values for arbitrary mammographic and x-ray spectra.Validated Monte Carlo methods were used to assess DgN values. One million x-ray photons (1-120 keV, in 1-keV increments) were input to a semicircular breast geometry of thicknesses from 2 to 12 cm and breast compositions from 0% to 100% glandular. DgN values for monoenergetic (1-120 keV) x-ray beams, polyenergetic (40-120 kV, tungsten anode) x-ray spectra, and polyenergetic mammographic spectra were computed. Skin thicknesses of 4-5 mm were used.The calculated DgN values were in agreement within approximately 1%-6% with previously published data, depending on breast composition. DgN tables were constructed for a variety of x-ray tube anode-filter combinations, including molybdenum anode-molybdenum filter, molybdenum anode-rhodium filter, rhodium anode-rhodium filter, tungsten anode-rhodium filter, tungsten anode-palladium filter, and tungsten anode-silver filter. DgN values also were graphed for monoenergetic beams to 120 keV and for general diagnostic x-ray beams to 120 kV.The tables and graphs may be useful for optimizing mammographic procedures. The higher energy data may be useful for investigations of the potential of dual-energy mammography or for calculation of dose in general diagnostic or computed tomographic procedures.

OBJECTIVE--To assess the effect of high dose inhaled corticosteroids on skin. DESIGN--Cross sectional study of patients receiving treatment for chest diseases. SETTING--Outpatient chest clinic in a teaching hospital. PATIENTS--68 Patients divided into four groups of similar age--namely, 15 receiving long term oral prednisolone, 21 receiving high dose inhaled corticosteroids, 15 receiving low dose inhaled corticosteroids, and 17 controls. MAIN OUTCOME MEASURES--Skin thickness at three sites measured by A scan ultrasound and clinical assessment of purpura. RESULTS--Compared with controls patients in both the oral prednisolone treated group and the high dose inhaled corticosteroid treated group had significantly thinner skin at all three sites (group median thicknesses: prednisolone treated group 28-33% less than controls; high dose inhaled corticosteroid treated group 15-19% less than controls). Differences in skin thicknesses between the low dose inhaled corticosteroid treated group and the controls were trivial. The prevalence of purpura was significantly greater in patients receiving oral prednisolone (12/15 patients) and high dose inhaled corticosteroids (10/21) than in controls (2/17). CONCLUSION--Skin thinning and purpura represent further evidence of systemic effects of high dose inhaled corticosteroids.

Purpose: Correct centering of the HDR source with the spherical MammoSite balloon is critical for proper brachytherapy delivery. We tested a MammoSite modified to incorporate a linear MOSFETdosimeter array to assess whether real‐time dosimetry measurements could confirm HDR source centering in MammoSite catheters. Method and Materials: A “MammoSite with MOSFETs” was simulated using a linear MOSFET array (Thomson Nielsen) consisting of 2 MOSFETs at the end of a flexible strip spaced 4 cm apart. The MOSFET array was placed along an uninflated 6‐French endobronchial catheter within a water‐equivalent solid phantom. This arrangement simulated having the detectors along the source pathway of a MammoSite, with the detectors within the balloon. The first detector was located at distal end of the “MammoSite” and the second at the proximal balloon collar. The HDR source was programmed to dwell at various positions relative to the “center” and MOSFET readings were obtained. Also, a prototype “MammoSite with MOSFETs” was built with the MOSFET array in a lumen adjacent to the source lumen. The scatter conditions (i.e., variable skin thicknesses) have been assessed by proximal MOSFET readings at various depths in a water phantom. Results: Ratio of the distal and proximal MOSFETs' readings showed high sensitivity to changes in dwell position. The fractional standard deviation of the ratio ranged from 0.9% to 3.2%, while each 1 mm shift from center caused at least 15% change in ratio. These ratios were not strongly affected by dose,dose rate, or nearby scatter media. Conclusion: The “MammoSite with MOSFETs” showed the potential to dosimetrically verify HDR source position with a linear resolution of 1mm or better. Further investigations are warranted to make this a routine clinical tool. Conflict of Interest: AH, Employed by Thomson‐Nielsen. JS, BS, MW, employed by Proxima Therapeutics.

A combined analytic and experimental program was conducted to determine sonic fatigue design properties of bonded structural sections based on skin-stringer-frame design commonly applied in aircraft and to formulate data and criteria for the development of sonic fatigue resistant designs of such structure. The FM73/BR127 adhesive system was used in the bonding of beam and multibay panel test specimens with 7075-T6 aluminum alloy skins and substructure. The metal surfaces that were bonded were treated with a phosphoric acid anodizing process that complied with the BAC-5555 specifications. Beam tests were conducted under narrow band shaker excitation and multibay panel tests were conducted under broadband acoustic excitation. The test results were evaluated and used in the development of a semi-empirical method for predicting sonic fatigue lives of multibay panels in acoustic environments. The range of applicability of the sonic fatigue design method is only partly determined. The sonic fatigue lives of the multibay acoustic test panels compared favorably with the lives of riveted panels of comparable size and skin thicknesses.

Sandwich constructions with high-quality PVC cellular plastic as core material and either metal or glassfibre/polyester skins are finding applications in an increasing number of vehicle systems. Simultaneously, computer-based structural design methods are developed, which significantly facilitates the work for the designer. In this paper, dual optimisation techniques are used together with a finite element code to find an optimum design of a refrigerated sandwich truck structure with PVC core and aluminium skins. The design variables include skin thicknesses and core thicknesses in seven different design areas of the truck. The weight is minimised with respect to these design variables with constraints on stresses in core and skin, and on certain deformations. An optimum is found after five iterations.

A global formula for the real part of the interaction between nuclei is developed for use in heavy-ion scattering under conditions of strong absorption. The formula is tested by comparisons of results of calculations of differential cross sections for 16 O projectiles incident on 48 Ca, 60 Ni, 120 Sn and 208 Pb. The advantage displayed by the formula, which is of Woods-Saxon form, but augmented by a small factor, is its explicit dependence on the density parameters of the projectile and target. The scattering process is seen to focus on specific regions specifying the matter distributions corresponding to different skin thicknesses.

THE St. Venant theory as applied to long beams of constant cross‐section could generally be used with sufficient accuracy for the solution of the structures encountered in aircraft until the last few years. The wings of high‐speed aircraft, with smaller aspect ratios, large angles of sweep‐back, and small thickness/chord ratios, introduce a new problem. There is an extensive literature on the subject, and all the methods which have been proposed are necessarily studies of redundant systems, the degree of redundancy varying according to the accuracy required. As these solutions require that the scantlings of the structure be known in advance, it was thought interesting to establish a simple method which would determine to a good approximation the skin thicknesses required. This is based on the application of the theorem of least work, which gives exact solutions of elasticity problems so long as all the terms in the strain energy expression are taken into account.

An investigation was conducted on a semi-monocoque box beam to determine the combined stress interaction curve for a corrugation-skin type of construction under combined compression and shear load. The investigation included the determination of initial buckling stresses and a comparison of measured stresses with computed stresses on the box beam. The interaction curve presented is most closely represented by the expression Rc + RS 1J = 1 where R is the appropriate stress ratio. Curves of effective width of skin versus corrugation stress, initial buckling stresses for several skin thicknesses, as well as the combined stress interaction curve are included.

When a body is situated at sufficiently great altitudes (about 200 km or above) it is exposed to impact by the meteorites which enter the earth's atmosphere. A preliminary attempt is made to estimate the probability that a body situated in the vicinity of the earth will be hit by a meteorite and, when hit does occur, to estimate the metal plate thickness necessary to prevent perforation by the impact of meteorites of different sizes. For stainless steel skin thicknesses ranging from 0.05 to 0.02 inch it is necessary to consider meteorites as small as those corresponding to magnitude 8 to 11, respectively. In general, however, it is found that for meteorites which are large enough to present a perforation hazard the probability of a hit is negligibly small, particularly if the body is not exposed to meteoritic impact for excessively long periods of time.

The mean total skin thicknesses (mm) for the breeds sampled were: Devon 8.15, Hereford 6.7, Zebu cross 6.43, Australian Illawarra Shorthorn 6.23, Friesian 6.0, Zebu 5.77, Aberdeen Angus 5.75, Shorthorn 5.69, and Jersey 5.46. The early maturing Shorthorn (Bos taurus L.) and the Zebu (Bos indicus L.) differed significantly in the depth of the papillary and reticular layers, and in the relative thickness of these skin layers. The mean thickness for the papillary layer; was 0.98 mm in the Zebu, 1.40 mm in the Zebu cross, and 1.70 mm in the Shorthorn. Thus the larger, more active sweat glands of the Zebu are more superficial. The corresponding reticular layer averaged 4.45 mm in the Zebu, 4.5 mm in the Zebu cross, and 4.08 mm in the Shorthorn. The thickness of the papillary layer relative to the total skin thickness was 18.3, 23.7, and 29.3 per cent., for the Zebu, Zebu cross, and Shorthorn respectively. The Zebu and the Jersey have relatively thin skins. Therefore a thick skin is not essential for adaptability to a hot environment. Inherent differences in the function of the follicles and the glands of the papillary layer may be critical characteristics for heat tolerance.