Modulation of Mechanical Interactions by Local Piezoelectric Effects

Piezoelectricity is a well‐established property of biological materials, yet its functional role has remained unclear. Here, a mechanical effect of piezoelectric domains resulting from collagen fibril organisation is demonstrated, and its role in tissue function and application to material design is described. Using a combination of scanning probe and nonlinear optical microscopy, a hierarchical structuring of piezoelectric domains in collagen‐rich tissues is observed, and their mechanical effects are explored in silico. Local electrostatic attraction and repulsion due to shear piezoelectricity in these domains modulate fibril interactions from the tens of nanometre (single fibril interactions) to the tens of micron (fibre interactions) level, analogous to modulated friction effects. The manipulation of domain size and organisation thus provides a capacity to tune energy storage, dissipation, stiffness, and damage resistance.     

Megasonic agitation for enhanced electrodeposition of copper

In this paper we propose an agitation method based on megasonic acoustic streaming to overcome the limitations in plating rate and uniformity of the metal deposits during the electroplating process. Megasonic agitation at a frequency of 1 MHz allows the reduction of the thickness of the Nernst diffusion layer to less than 600 nm. Two applications that demonstrate the benefits of megasonic acoustic streaming are presented: the formation of uniform ultra-fine pitch flip-chip bumps and the metallisation of high aspect ratio microvias. For the latter application, a multi-physics based numerical simulation is implemented to describe the hydrodynamics introduced by the acoustic waves as they travel inside the deep microvias.     

矿用高强度圆环链及其热处理的研究进展

介绍了矿用高强度圆环链的研究进展,包括链条用钢、热处理技术的发展、链环尺寸形状的优化、链条设计制造及其力学性能的改善等.     

A novel method to dope diamond — Ion Beam Nuclear Transmutation Doping (IBNTD)

Using MeV-range protons to transmute a small fraction of host nuclei into n- or p-type dopants, we have demonstrated a novel method to dope challenging wide bandgap semiconductors. In particular, we have doped isotopically-enriched ¹³C diamond and AlGaN films using this method focusing on the ¹³C + ¹H → ¹⁴N + γ, radiative proton capture resonance at 1.75 MeV and ²⁷Al + ¹H → ²⁸Si + γ proton capture resonance at 0.997 MeV. Both samples sustained primarily end-of-range damage which was annealable in AlGaN. We have performed a variety of measurements to characterize the doped samples including Raman spectroscopy, STM, and X-ray diffraction on the doped samples which suggest the viability of IBNTD as a doping method. Calculations indicate that doping layer thicknesses of the order of 10 nm are achievable. Possible doping concentrations using this technique are also estimated.     

Comparing Public Perceptions of Alternative Water Sources for Potable Use: The Case of Rainwater,Stormwater, Desalinated Water,and Recycled Water

This research investigated how people’s perceptions of alternative water sources compare with their perceptions of other technologies, and identified significant predictors of comfort with different alternative water sources. We drew on data from four questionnaire survey studies with a total sample of more than 1200 Australian participants. Relative levels of comfort with the alternative water sources was consistent across the four studies: comfort was always highest for drinking rainwater and lowest for drinking recycled water, with comfort with drinking treated stormwater and desalinated water sitting between these two. Although comfort with drinking recycled water was always lowest of the four alternative water sources, participants were significantly more comfortable with drinking recycled water than they were with nuclear energy, or with using genetically modified plants and animals for food. In general, demographic variables were less important predictors of comfort with alternative water sources than were psychological variables; only age and gender emerged as relatively consistent predictors for recycled water, stormwater, and desalinated water, with older participants and males more comfortable with drinking these water sources. Of the psychological variables, participants’ comfort with technology in general, trust in science and trust in government emerged consistently as significant positive predictors of comfort with drinking recycled water, stormwater, and desalinated water.

     

An evaluation of the sex stereotyping effect as related to counselor perceptions of courses appropriate for high school students.

Compared the appropriateness of course choices made by 96 female and male high school counselees as rated by 13 female and male counselors to determine if there was a sex bias effect. The sex, grade, and the ability level of ratees were controlled for in a 4-way analysis of variance. The Ss were randomly assigned to each counselor to ensure equal numbers of males and females from each grade and each ability level. The counselors were given achievement information, ability-level data, courses previously taken, grades received, and information about future plans. Each S was rated 5 times by the counselors. No significant differences were found between the ratings of the female and male counselors. Significant findings are (a) the higher the ability level of the counselee, the more appropriate were the courses; and (b) females were rated as having more appropriate courses than were males (using post hoc procedures, the significant difference occurring at the junior year in high school). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hematopoiesis in dogs irradiated with protons in lethal doses with screening of the bone marrow]

The paper presents the results of a 6-year investigation of hemopoiesis of dogs which were exposed to double irradiations (with a 1.5-month interval) with protons at a dose of 350 rad when different parts of the body (head, chest, abdomen, pelvis) were shielded. Throughout the entire period the dogs showed moderate leucopenia and by the end of the investigation insignificant anemia. The dogs irradiated with shielded abdomen displayed disturbances in bone marrow hemopoiesis, whereas other dogs exhibited relative, although transient, normalization. All the dogs showed a significant decrease of erythropoiesis and a relative stability of leucopoiesis as well as a significant elevation of the number of reticulocytes, monocytes and plasmocytes 5.5 year after irradiation.     

Sympathetic response to stimulation of the pontine A5 region in conscious rabbits

OBJECT: This study is a retrospective analysis of clinical data obtained in 28 patients affected by obstructive hydrocephalus who presented with signs of midbrain dysfunction during episodes of shunt malfunction. METHODS: All patients presented with an upward gaze palsy, sometimes associated with other signs of oculomotor dysfunction. In seven cases the ocular signs remained isolated and resolved rapidly after shunt revision. In 21 cases the ocular signs were variably associated with other clinical manifestations such as pyramidal and extrapyramidal deficits, memory disturbances, mutism, or alterations in consciousness. Resolution of these symptoms after shunt revision was usually slow. In four cases a transient paradoxical aggravation was observed at the time of shunt revision. In 11 cases ventriculocistemostomy allowed resolution of the symptoms and withdrawal of the shunt. Simultaneous supratentorial and infratentorial intracranial pressure recordings performed in seven of the patients showed a pressure gradient between the supratentorial and infratentorial compartments, with a higher supratentorial pressure before shunt revision. Inversion of this pressure gradient was observed after shunt revision and resolution of the gradient was observed in one case after third ventriculostomy. In six recent cases, a focal midbrain hyperintensity was evidenced on T2-weighted magnetic resonance imaging sequences at the time of shunt malfunction. This rapidly resolved after the patient underwent third ventriculostomy. CONCLUSIONS: It is probable that in obstructive hydrocephalus, at the time of shunt malfunction, the development of a transtentorial pressure gradient could initially induce a functional impairment of the upper midbrain, inducing upward gaze palsy. The persistence of the gradient could lead to a global dysfunction of the upper midbrain. Third ventriculostomy contributes to equalization of cerebrospinal fluid pressure across the tentorium by restoring free communication between the infratentorial and supratentorial compartments, resulting in resolution of the patient's clinical symptoms.