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Different models have been used to evaluate the interfacial Dzyaloshinskii–Moriya interaction (DMI) from the asymmetric bubble expansion method using magneto-optics. Here, we investigate the most promising candidates over a range of different magnetic multilayers with perpendicular anisotropy. Models based on the standard creep hypothesis are not able to reproduce the domain wall (DW) velocity profile when the DW roughness is high. Our results demonstrate that the DW roughness and the interface roughness of the sample layers are correlated. Furthermore, we give guidance on how to obtain reliable results for the DMI value with this popular method. A comparison of the results with Brillouin light scattering (BLS) measurements on the same samples shows that the BLS approach often results in higher measured values of DMI. [ABSTRACT FROM AUTHOR]

The Atacama Desert, on the western margin of the Central Andes, hosts some of the world's largest porphyry copper deposits (PCDs). Despite a hyperarid climate, many of these PCDs have undergone secondary "supergene" enrichment, whereby copper has been concentrated via groundwater-driven leaching and reprecipitation, yielding supergene profiles containing valuable records of weathering and landscape evolution. We combine hematite (U-Th-Sm)/He geochronology and oxygen isotope analysis to compare the weathering histories of two Andean PCDs and test the relative importance of climate and tectonics in controlling both enrichment and water table movement. At Cerro Colorado, in the Precordillera, hematite precipitation records prolonged weathering from ~31 to ~2 Ma, tracking water table descent following aridity-induced canyon incision from the late Miocene onward. By contrast, hematite at Spence, within the Central Depression, is mostly younger than ~10.5 Ma, suggesting exhumation ended much later. A heavy oxygen isotopic signature for Spence hematite suggests that upwelling formation water has been an important source of groundwater, accounting for a high modern water table despite persistent hyperaridity, whereas isotopically light hematite at Cerro Colorado formed in the presence of meteoric water. Compared with published paleo-environmental and sedimentological records, our data show that weathering can persist beneath appreciable post-exhumation cover, under hyperarid conditions unconducive to enrichment. The susceptibility of each deposit to aridity-induced water table descent, canyon incision and deep weathering has been controlled by recharge characteristics and morphotectonic setting. Erosional exhumation, rather than aridity-induced water table decay, appears to be more important for the development of supergene enrichment. [ABSTRACT FROM AUTHOR]

We determined the spin-transport properties of Pd and Pt thin films by measuring the increase in ferromagnetic resonance damping due to spin-pumping in ferromagnetic (FM)-nonferromagnetic metal (NM) multilayers with varying NM thicknesses. The increase in damping with NM thickness depends strongly on both the spin- and charge-transport properties of the NM, as modeled by diffusion equations that include both momentum- and spin-scattering parameters. We use the analytical solution to the spin-diffusion equations to obtain spin-diffusion lengths for Pt and Pd. By measuring the dependence of conductivity on NM thickness, we correlate the charge- and spin-transport parameters, and validate the applicability of various models for momentum-scattering and spin-scattering rates in these systems: constant, inverse-proportional (Dyakanov-Perel), and linear-proportional (Elliot-Yafet). We confirm previous reports that the spin-scattering time appears to be shorter than the momentum scattering time in Pt, and the Dyakanov-Perel-like model is the best fit to the data. [ABSTRACT FROM AUTHOR]

Motivated by the importance of magnetization dynamics in nanomagnets for the development and optimization of magnetic devices and sensors, we measured and modeled spin wave spectra in patterned elliptical nanomagnets. Ferromagnetic resonance spectra for multiple nanomagnets of Ni80Fe20, fabricated by electron-beam lithography to have nominal short-axes of 200 nm or 100 nm, were measured by use of heterodyne magneto-optical microwave microscopy. Scanning electron microscope images taken of the same nanomagnets were used to define element shapes for micromagnetic simulations. The measured spectra show significant differences between nominally identical nanomagnets, which could be only partially attributed to uncontrolled shape variations in the patterning process, as evidenced by the limited agreement between the measured and simulated spectra. Agreement between measurements and simulations was improved by including a zone of reduced magnetization and exchange at the edges of the nanomagnets in the simulations. Our results show that the reduction of shape variations between individual magnetic random-access memory elements can potentially improve their performance. However, unambiguous determination of materials parameters in nanomagnets based on analysis and modeling of spin wave spectra remains problematic. [ABSTRACT FROM AUTHOR]

Skyrmions can be stabilized in magnetic systems with broken inversion symmetry and chiral interactions, such as Dzyaloshinskii-Moriya interactions (DMI). Further, compensation of magnetic moments in ferrimagnetic materials can significantly reduce magnetic dipolar interactions, which tend to favor large skyrmions. Tuning DMI is essential to control skyrmion properties, with symmetry breaking at interfaces offering the greatest flexibility. However, in contrast to the ferromagnet case, few studies have investigated interfacial DMI in ferrimagnets. Here we present a systematic study of DMI in ferrimagnetic CoGd films by Brillouin light scattering. We demonstrate the ability to control DMI by the CoGd cap layer composition, the stack symmetry and the ferrimagnetic layer thickness. The DMI thickness dependence confirms its interfacial nature. In addition, magnetic force microscopy reveals the ability to tune DMI in a range that stabilizes sub-100 nm skyrmions at room temperature in zero field. Our work opens new paths for controlling interfacial DMI in ferrimagnets to nucleate and manipulate skyrmions. [ABSTRACT FROM AUTHOR]

The spin dynamics of sub-100-nm Ni80Fe20 nanomagnets are directly measured using the magneto-optic Kerr effect and a broadband detection scheme. Elliptical dots approximately 68 nm in diameter and 10 nm thick were fabricated in 20×20 μm2 arrays. There is approximately a factor of 2 increase in the effective linewidth when compared to a 20 μm diameter continuous disk of the same material. Using micromagnetic simulations, we model the effect of dot-to-dot size variation on the effective linewidth and find that 2 nm size variations are more than sufficient to account for the effective increase in linewidth. [ABSTRACT FROM AUTHOR]

A single monolayer (ML) of Cr was found to have a significant effect on the magnetic properties of subsequently deposited ultra-thin epitaxial Co layers. Brillouin light scattering (BLS) indicated that the Cr interlayer reversed the sign of the interface contribution to the total perpendicular magnetic anisotropy (PMA) of the Co. The negative value of the interfacial anisotropy term implied in-plane behavior. As a result, the samples with Cr became in-plane at about 11 ML of Co (1 ML of Co is about 0.2 nm), but the structures without Cr, while behaving qualitatively similar, exhibited higher total PMA and became in-plane at about 13 ML of Co. This behavior was also confirmed using perpendicular magneto-optic Kerr effect measurements. These results suggested that the in-plane nature of the interface anisotropy term for those samples with Cr was significant in determining their greater sensitivity to increased Co thickness. The impact of interdiffusion at the Cr/Co interface should not be neglected; by itself Cr is antiferromagnetic, and as an additive to Co and with no diffusion to grain boundaries (these films are single crystal), a greater effect from it is expected than from simple diluents such as Cu or Au. A monotonic decrease in magnetization with decreasing Co thickness was observed, but only for the samples with Cr, further suggesting the importance of interdiffusion. [ABSTRACT FROM AUTHOR]

The development and baseline operation of an acoustic view cell for observing fluids, and fluid-fluid and fluid-solid interfaces in porous media over the frequency range of 10-5000 Hz is described. This range includes the industrially relevant frequency range 500-5000 Hz that is not covered by existing devices. Pressure waveforms of arbitrary shape are generated in a 17.46 mm ID by 200 mm and 690.5 mm long glass tubes at flow rates up to 200 ml/min using a syringe pump. Peak-to-peak amplitudes exceeding 80 kPa are readily realized at frequencies from 10 to 5000 Hz in bubble free fluids when actuated with 20 Vpp as exemplified using castor oil. At resonant frequencies, peak-to-peak pressure amplitudes exceeding 500 kPa were obtained (castor oil at 2100 Hz when actuated with 20 Vpp). Impacts of vibration on macroscopic liquid-liquid and liquid-vapour interfaces and interface movement are illustrated. Pressure wave transmission and attenuation in a fluid saturated porous medium, randomly packed 250-330 μm spherical silica beads, is also demonstrated. Attenuation differences and frequency shifts in resonant peaks are used to detect the presence and generation of dispersed micro-bubbles (<180 μm diameter), and bubbles within porous media that are not readily visualized. Envisioned applications include assessment of the impacts of vibration on reaction, mass transfer, and flow/flow pattern outcomes. This knowledge will inform laboratory and pilot scale process studies, where nuisance vibrations may affect the interpretation of process outcomes, and large scale or in situ processes in aquifers or hydrocarbon reservoirs where imposed vibration may be deployed to improve aspects of process performance. Future work will include miscible interface observation and quantitative measurements in the bulk and in porous media where the roles of micro-bubbles comprise subjects of special interest. [ABSTRACT FROM AUTHOR]

Two parallel multi-element ultrasonic acoustic arrays combined with sets of focal laws for acoustic signal generation and a classical tomographic inversion algorithm are used to generate real-time two-dimensional micro seismic acoustic images of multiphase materials. Proof of concept and calibration measurements were performed for single phase and two phase liquids, uniform polyvinyl chloride (PVC) plates, and aluminum cylinders imbedded in PVC plates. Measurement artefacts, arising from the limited range of viewing angles, and the compromise between data acquisition rate and image quality are discussed. The angle range of scanning and the image resolution were varied, and the effects on the quality of the reproduction of the speed of sound profiles of model solids and liquids with known geometries and compositions were analysed in detail. The best image quality results were obtained for a scanning angle range of [-35°, 35°] at a step size of 2.5° post processed to generate images on a 40 µm square grid. The data acquisition time for high quality images with a 30 mm x 40 mm view field is 10 min. Representation of two-phase solids with large differences in speed of sound between phases and where one phase is dispersed in the form of macroscopic objects (greater than 1 mm in diameter) proved to be the most difficult to image accurately. Liquid-liquid and liquid-vapor phase boundaries, in micro porous solids by contrast, were more readily defined. Displacement of air by water and water by heptane in natural porous limestone provides illustrative kinetic examples. Measurement results with these realistic cases demonstrate the feasibility of the technique to monitor in real time and on the micrometer length scale local composition and flow of organic liquids in inorganic porous media, one of many envisioned engineering applications. Improvement of data acquisition rate is an area for future collaborative study. [ABSTRACT FROM AUTHOR]

Speed of sound and acoustic wave attenuation are sensitive to fluid phase composition and to the presence of liquid-liquid interfaces. In this work, the use of an acoustic array comprising 64 elements as a non-intrusive sensor for liquid-liquid interface, phase separation kinetics measurement in bulk fluids, and local composition measurement in porous media is illustrated. Three benchmark examples: the phase behaviour of methanol + mixed hexanes and methanol + heptane mixtures at 25.0 °C and 1 bar, and Athabasca bitumen + heptane in a synthetic silica porous medium at 22.5 °C and 1 bar, illustrate the accuracy of liquid-liquid interface and potential research and industrial applications of the technique. Liquid-liquid interfaces can be detected independently using both speed of sound and acoustic wave attenuation measurements. The precision of the interface location measurement is 300 μm. As complete scans can be performed at a rate of 1 Hz, phase separation kinetics and diffusion of liquids within porous media are readily tracked. The technique is expected to find application where the fluids or porous media are opaque to visible light and where other imaging techniques are not readily applied, or are too costly. A current limitation is that the acoustic probes must be cooled to less than 315 K in order for them to operate. [ABSTRACT FROM AUTHOR]

This paper explores the role of ethics in the work a forensic engineer performs in relation to a project that might progress to a court hearing in which the engineer will give evidence. [ABSTRACT FROM AUTHOR]

The article focuses on a study on the use of self-expanding metal stents (SEMS) as an alternative to surgical bypass for malignant gastric outlet obstruction. The study included 70 patients who underwent SEMS placement for hepatobiliary and pancreatic malignancy and antral gastric carcinoma. It concluded that SEMS can successfully alleviate complete malignant gastric outlet obstruction in patients with limited life expectancy.

Liquid-phase mutual diffusion coefficients are a key parameter in reservoir simulation models related to both primary production and envisioned secondary recovery processes for heavy oil and bitumen. The measurement of liquid-phase mutual diffusion coefficients in bitumen and heavy oil + light hydrocarbon or gas mixtures present numerous experimental and data analysis challenges due to the viscosity and opacity of the mixtures, the variability of density, viscosity and mutual diffusion coefficient with composition, and the multi-phase nature of these mixtures. Data analysis challenges are particularly acute. For example, recently reported mutual diffusion coefficient values for liquid mixtures of bitumen + carbon dioxide vary over three orders of magnitude when different analysis methods are applied to the same experimental data. In this contribution, we illustrate the importance of measuring composition profiles within liquids as a function of time, as a basis for mutual diffusion coefficient computation, and for allowing explicitly for the variation of diffusion coefficient and liquid density with composition in the analysis of composition profile data. Such inclusions eliminate apparent temporal variations of mutual diffusion coefficients and yield values consistent with relevant theories and exogenous data sets. Liquid-phase mutual diffusion coefficients computed for the mixtures Athabasca Bitumen + pentane and Cold Lake Bitumen + heptane exemplify the experimental and data analysis approaches. [ABSTRACT FROM AUTHOR]

Exercise that imparts rapid, high-magnitude mechanical loading is considered to be advantageous to bone health. Previous rodent studies have suggested that swimming may also be beneficial to bone. We investigated the differential effects of exercise with and without weight bearing on cortical and trabecular bone. Forty female Sprague-Dawley rats (120 days) were weight-stratified and randomized into four groups: swim control (Cs, n = 10), swim (S, n = 10), treadmill control (Ct, n = 10), and treadmill (T, n = 10). Treadmill speed was adjusted to match the average limb loading frequency used for swimming, and all training progressed to 1 hour/day, 5 days/week, for 12 weeks. Femurs and humeri were assessed for cortical morphometry by peripheral quantitative computed tomography, areal bone mineral density (BMD) by peripheral dual-energy X-ray absorptiometry, mineral content by ashing, strength by three-point bending, and trabecular volume (BV/TV) by micro-computed tomography. Swimming was associated with increases in cortical thickness and BMD in the humerus midshaft and trabecular BV/TV in the distal femur and proximal humerus compared with age-matched controls. Compared to swimming, treadmill training was associated with increases in percent ash of the femur and humerus and Young's modulus of the femur. Swimming appears to engender novel bone strains and osteogenic adaptations in the humerus and femur, which are different from those induced by normal cage activity. In summary, our findings suggest that when limb loading frequency is matched, swimming may afford greater benefits to cortical and trabecular bone than uphill treadmill work in rats. [ABSTRACT FROM AUTHOR]

The treatment of acute and recurrent variceal bleeding is best accomplished by a skilled, knowledgeable, and well-equipped team using a multidisciplinary integrated approach. Optimal management should provide the full spectrum of treatment options including pharmacologic therapy, endoscopic treatment, interventional radiologic procedures, surgical shunts, and liver transplantation. Endoscopic therapy with either band ligation or injection sclerotherapy is an integral component of the management of acute variceal bleeding and of the long-term treatment of patients after a variceal bleed. Variceal eradication with endoscopic ligation requires fewer endoscopic treatment sessions and causes substantially less esophageal complications than does injection sclerotherapy. Although the incidence of early gastrointestinal rebleeding is reduced by endoscopic ligation in most studies, there is no overall survival benefit relative to injection sclerotherapy. Simultaneous combined ligation and sclerotherapy confers no advantage over ligation alone. A sequential staged approach with initial endoscopic ligation followed by sclerotherapy when varices are small may prove to he the optimal method of reducing variceal recurrence. Overall, current data demonstrate clear advantages for using ligation in preference to sclerotherapy. Ligation should therefore he considered the endoscopic treatment of choice in the treatment of esophageal varices. [ABSTRACT FROM AUTHOR]

Cryostorage of nonhuman primate embryos by time-consuming slow-cooling methods is often limited to early cleavage stages. Effective rapid-cooling methods have been developed for many species and represent valuable tools for laboratory- and field-based studies of nonhuman primate reproductive biology. However, few rapid-cooling protocols have been applied to nonhuman primate embryos in terms of comparing various developmental stages. Here we compare slow cooling vs. two- and three-step rapid cooling of two-, four-, and eight-cell Macaca fascicularis (Mf ) embryos. Rapid cooling was conducted in open pulled straws (OPS) using cooling solutions containing reduced quantities of ethylene glycol (EG) and supplemented with either of two high-molecular-weight polymers, ficoll and dextran. The survival of the slow-cooled embryos, but not the rapid-cooled embryos, was independent of embryonic stage at cryostorage. Slow cooling was associated with greater cell survival (82%) post thaw compared to warming following rapid cooling (18–29%). Slow cooling resulted in a high proportion of embryo survival (18/20; 90%) and cleavage (15/18; 83%) post thaw. Rapid cooling resulted in significantly reduced percentages of embryo survival (26–32%) and embryo cleavage in culture (29–38%) after warming. Conventional slow cooling was more effective than the rapid-cooling protocols employed in this study for cryopreservation of early-cleavage-stage Mf embryos. Am. J. Primatol. 58:169–174, 2002. © 2002 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Leucocyte adhesion deficiency (LAD) is a hereditary disorder caused by mutations in the CD18 (β2 integrin) gene. Four missense mutations have been identified in three patients. CD18(A270V) supports, at a diminished level, CD11b/CD18 (Mac-1, αMβ2 integrin) and CD11c/CD18 (p150,95, αXβ2 integrin) expression and function but not CD11a/CD18 (LFA-1, αLβ2 integrin) expression. Conversely, CD18(A341P) supports a limited level of expression and function of CD11a/CD18, but not of the other two CD11/CD18 antigens. CD18(C590R) and CD18(R593C) show a decreasing capacity to associate with the CD11a, CD11c and CD11b subunits. Transfectants expressing the CD11a/CD18 with the C590R and R593C mutations are more adhesive than transfectants expressing wild-type LFA-1, and express the reporter epitope of the monoclonal antibody 24 constitutively. Thus, the four mutations affect CD18 differently in its capacities to support CD11/CD18 expression and adhesion. These results not only provide a biochemical account for the clinical diversity of patients with leucocyte adhesion deficiency, but also offer novel insights into the structural basis of interaction between the α and β subunits, which is an integral component in our understanding of integrin-mediated adhesion and its regulation. [ABSTRACT FROM AUTHOR]

Double packaging, in which an inner straw containing the specimen is inserted into an outer, larger straw (here termed 'straw-in-straw') to prevent the inner straw from coming into direct contact with liquid nitrogen provides a simple strategy for reducing or eliminating the potential contamination risk associated with storage in liquid nitrogen. This approach has in the past been used in conjunction with cryopreservation by slow cooling, but has not previously been tested for use throughout an entire rapid cooling and warming procedure. This study determined whether keeping the straw containing the embryos inside a second protecting container throughout the cryopreservation and storage protocol would compromise embryo viability. We established that a cryoprotectant containing a high polymer concentration (35% dextran or Ficoll) together with 25% ethylene glycol (as the penetrating cryoprotectant) was highly effective for day 2 and day 3 mouse embryos in both single and double straws. The survival and development of all cryopreserved embryos, as assessed both in vitro and in vivo, was not statistically different to their untreated controls. This established that a protein/serum-free cryoprotectant solution supplemented with polymers could provide complete protection of mouse embryos. It also shows, for the first time, that embryos can be cooled by direct immersion in liquid nitrogen and warmed by direct immersion into a waterbath within a double straw arrangement to reduce the likelihood of contamination. [ABSTRACT FROM AUTHOR]

The dose response curves of purified normal and chronic lymphocytic leukaemic lymphocytes to highly, purified phytohaemagglutinin in 3- and 6-day cultures have been defined. Normal lymphocytes cultured for 3 days were maximally stimulated by low concentrations of phytohaemagglutinin, in the range 0.4 to 1.4 μg phytohaemagglutinin/106 cells/ml. Higher concentrations of phytohaemagglutinin caused no further stimulation. Normal lymphocytes cultured for 6 days showed a progressively greater response to increasing concentrations of phytohaemaggluttnin up to 15 μg phytohaemagglutinin/106 cells/ml. Chronic lymphocytic leukaemic lymphocytes responded subnormally to all ranges of phytohaemagglutinin concentrations tested, m both 3- and 6-day cultures. The shape of the dose response curve resembled the normal curve in 2 of 5 cases of chronic lymphocytic leukaemic lymphocytes studied in 3-day cultures, and in all 7 cases studied in 8-day cultures. No evidence could be adduced of a consistently greater response of chronic lymphocytic leukaemic lymphocytes in 6-day compared with 3-day cultures. Five hours' exposure of normal lymphocytes to an optimum phytohaemagglutinin dose did not result in maximum H³-thymidine incorporation after 3 days in culture. [ABSTRACT FROM AUTHOR]

Girls and young women who require ovariectomy or cancer therapy may consider having their own eggs, embryos or ovarian tissue stored (cryopreserved) for their own future use. Ovarian tissue is simple to collect and contains large numbers of germ cells. Transplantation of fresh and frozen-thawed ovarian tissue in healthy sheep and mice has resulted in normal live young. Similar techniques may be effective in the human but it is unclear whether ovarian tissue cryopreservation and grafting is suitable for ovaries from individuals with cancer or infections. If cancer cells were present in an ovary at the time of collection and survived cryopreservation and grafting they could establish cancer in the recipient. We therefore performed ovarian cryopreservation and transplantation trials using a mouse lymphoma model. This established that the lymphoma was transmitted by grafts of both fresh and frozen ovarian tissue. The normal healthy recipient mice died 9-43 days after receiving a small piece (1 mm3) of ovarian tissue from a donor with lymphoma. We conclude that ovarian tissue which is collected, cryopreserved and grafted while it contains cancer cells has the potential to spread the cancer to the graft recipient. [ABSTRACT FROM AUTHOR]

Mouse pronuclear and 4-cell embryos were cryopreserved by slow cooling to -33 degrees C in 1.5 M 1,2-propanediol or 1.5 M ethylene glycol, with or without 0.1 M sucrose. Straws were thawed by immersion into a 37 degrees C water bath, immediately after their removal from liquid nitrogen (protocol 1), or after being held in air for 15 (protocol 2) or 30 s (protocol 3). Others were held in air until the ice melted (protocol 4). Embryos which formed blastocysts that hatched and attached to the Petri dish in vitro (plated) were considered viable. The thawing protocol did not significantly influence the viability of embryos frozen in propanediol with 0.1 M sucrose (52-72% of pronuclear and 69-97% of 4-cell embryos plated). In the other solutions tested, propanediol without sucrose and ethylene glycol with/without sucrose, only protocol 2 resulted in uniformly high development of both pronuclear (45-65% plating) and 4-cell embryos (70-97% plating). Thawing protocol 4 significantly reduced development, in particular for embryos frozen in ethylene glycol (0% 1-cell; 0-25% 4-cell plating). The difference between thawing protocols 2 and 4 was reduced by continuing slow cooling of ethylene glycol solutions to lower temperatures (-41 degrees C). Adding antifreeze proteins type I or III did not improve survival or development. Thus, although mouse pronuclear and 4-cell embryos can be frozen-thawed in either ethylene glycol or propanediol without significant loss of viability, an appropriate thawing protocol is essential for embryos frozen in ethylene glycol or propanediol-sucrose. [ABSTRACT FROM AUTHOR]

While optimizing the ultrarapid embryo freezing procedure we noted that embryo survival was lowest when gas bubbles formed in the straws. Here we report the influences of gassing the freezing solutions with 5% CO2 in air, degassing the solution, the pH of the medium and straw irradiation on the survival and development in vitro of 2-cell mouse embryos. Embryos were ultrarapidly frozen in medium M2 containing 3 M dimethyl sulphoxide and 0.25 M sucrose. Significantly fewer embryos survived freezing and thawing in gassed solutions. The subsequent development of intact embryos to blastocysts was similar in gassed and non-gassed solutions. Survival and development of embryos frozen in solutions of pH 7.0, 7.6 or 8.0 was similar, but fewer embryos developed to blastocysts after freezing in media at pH 6.0. In straws sterilized by gamma irradiation before use, embryo survival after freezing and thawing was dramatically reduced compared with that seen when non-irradiated straws were used. With non-gassed solutions significantly more gas bubbles formed in irradiated straws than in non-irradiated straws. Although bubble formation was significantly reduced in all straws by using degassed freezing solutions, this did not improve embryo survival. We conclude that under conditions normally used for ultrarapid freezing, dissolved gas and pH have less effect on embryo viability than the use of irradiated straws. [ABSTRACT FROM AUTHOR]

Background: Bone mass and fall propensity are two major risk factors for hip fracture. Our intent was to determine if weight-bearing exercises with added resistance from weighted vests would improve dynamic balance, muscle strength and power, and bone mass in postmenopausal women, thereby reducing risk for falls and hip fracture.Methods: Forty-four nonsmoking, community-dwelling, Caucasian women aged 50-75 years participated in the study. All participants were at least 5 years past menopause and most were estrogen-deplete (n = 36). Bone mass and body composition were assessed by dual-energy x-ray absorptiometry, muscular strength by isokinetic dynamometry, muscular power by modified Wingate Anaerobic Power Test, and indices of postural stability by dynamic posturography. Half of the subjects participated in a 9-month regimen of weight-bearing exercises performed three times a week that emphasized lower-body muscle strength and power development. Resistance was added progressively and individually by the use of a weighted vest. Controls maintained customary diet and activity patterns.Results: Significant improvements were observed for indices of lateral stability, lower-body muscular strength (16-33% increase), muscular power (13% increase), and leg lean mass (3.5% increase) in exercisers vs controls (p < .05). No significant changes (p > .05) were detected for femoral neck bone mass in exercisers or controls at the conclusion of the trial.Conclusions: Lower body exercise, using a weighted vest for resistance, provides an effective means of improving key indices of falls in postmenopausal women. [ABSTRACT FROM AUTHOR]

We studied the microwave assisted magnetic reversal of 65×71 nm2 elliptical Ni80Fe20 nanomagnets. Hysteresis curves were measured by magneto-optical Kerr effect for a range of microwave frequencies and amplitudes. The coercive field Hc was reduced by 26% for an rf field of 0.08Hc when the microwave frequency coincided with the minimum of the experimentally determined ferromagnetic resonance frequency with varying dc field. The experimental results for the fractional reduction in Hc with rf field amplitude are in good agreement with numerical simulations for an array of interacting macrospins with a physically realistic shape anisotropy distribution. [ABSTRACT FROM AUTHOR]

Ciliated hepatic foregut cysts are an unusual congenital cause of cystic liver lesions. Although most are benign, 4.4% of reported cases have been shown to harbor squamous cell carcinoma. Diagnostic uncertainty or misdiagnosis frequently results in surgical exploration. We present a case of a ciliated hepatic foregut cyst and review this uncommon condition. [ABSTRACT FROM AUTHOR]

Dynamic wavelength stabilization of an AlGaAs diode laser has been demonstrated. The diode laser is butt coupled to a stripe-loaded optical waveguide which contains a Bragg reflecting grating. The laser is pulsed with 50-ns-long, 25% duty cycle, 100% modulation depth pulses and the waveguide output is observed to remain at single wavelengths over a peak current range of 120-160 mA and 15 °C temperature variations. [ABSTRACT FROM AUTHOR]