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One of the key enablers for the successful integration of 3-D interconnects using the Through-Silicon Via (TSV) schemes is the control of the mechanical stresses in the Cu TSV itself as well as in the surrounding silicon substrate. The synchrotron-sourced X-ray microdiffraction technique has been recognized to allow some important advantages compared to other techniques in characterization of the mechanical stresses in a TSV sample. This approach have been used to study Cu TSV samples from SK Hynix, Inc. earlier as well as more recently from SEMATECH, and we have found interesting differences in the stress states of the Cu TSV. We proposed a possible explanation of the observed differences. This fundamental understanding could lead to improved stress control and hence reliability in the Cu TSV samples, as well as to reduce its impact to the silicon electron mobility and hence to device performance in general.

With the demand for the materials are increasing in the field of military and civilian application with each passing day, an ultrasonic-electric surface modification treatment was employed to improve the surface properties of metal material with different heat-treated conditions. The surface properties of the specimens after conventional cutting and ultrasonic-electric surface modification treatment were characterized, respectively. A grain refinement layer was formed on the surface of different heat-treated specimens after ultrasonic-electric surface modification treatments. The average grain size on the top surface was refined into the submicrometer or nanometers scale. This is caused mainly by two aspects: one is the accumulation of initial tiny particles during deformation; the other is that the ferrite is smashed into pieces due to micro-fatigue damage. Moreover, it was found out the specimens after ultrasonic-electric surface modification treatment had shown the optimal surface properties and friction-wear properties.

To increase the exit velocity of projectile from single-stage reluctance coil launcher, the theoretical analysis is conducted for the projectile acceleration principle. The influence law of the electrical parameters on the projectile velocity is obtained, by the imitation research about the influence rule of the variation of electrical parameters (including capacitor voltage and capacitance) in a single-stage reluctance coil emitter on the transmitting performance, using the two-dimensional transient field solver in the finite element analysis software of Ansoft. At the same time, the single-stage reluctance coil launcher is also set up to conduct relevant tests, and the correctness of simulation analysis is verified. The results show that increasing the voltage and capacitance of the capacitor is beneficial to increase the exit velocity of the projectile, in the condition that the relative position of the projectile and driving coil is constant, The capacitor voltage is less than 1000V, and the capacitor capacitance is less than 1500μF. The simulation and experiment results provide guidance for the related analysis and study of multi-stage reluctance coil launcher.

This paper proposed a two layered 2 × 1 Koch Curve patch array antenna design with suspended air gap technique for Wireless Local Area Network (WLAN) application of 2.4 GHz resonant frequency. This proposed patch antenna is using two FR-4 substrate layers with dielectric constant, e r = 4.4 and the electrical conductivity tangent loss, tanΔ = 0.019. It is using the suspended air gap technique between two layers for enhancement effect of antenna gain from 4.89 dB to 5.18 dB. At the upper part of substrate, it consists a two feeding networks that connected the two patch of Koch Curve array patch. Beside antenna gain, this technique also improves the bandwidth and return loss of the antenna. It also contains a Koch Curve array structure at the patch part and have a full ground of copper at the back. This Koch Curve is design based on the basic equilateral triangle with three iteration steps. For the first iteration step, it be made up of the equilateral triangular shaped while the second iteration are added with mirror design of equilateral triangular to create a six segment of star-shaped. For the third iteration step, the equilateral triangle with the length base on previous iteration step is constructed on top of the side line of the base triangle. This third iteration step of the Koch Curve effect the reduction size of the patch antenna from 100 mm × 100mm to only 90mm × 60 mm. The return loss performance at resonant frequency 2.4 GHz is −32.735 dB.

Pressurizer surge lines are essential pipeline structure in NPPs, and the thermal stratification in surge line is recognized as one of the possible cause of thermal fatigue. In this paper, a Computational Fluid Dynamic (CFD) method has been adopted to simulate temperature fluctuations on the process of temperature rising in a pressurizer surge line under rolling motion of single degree of freedom. This work focuses on a fundamental description of differences of thermal stratification between the surge line rolling around the coordinate X-axis condition and that in a static state. The Large-eddy simulation (LES) model is employed to capture the details of temperature change in surge line. Temperature distributions near the inner wall of a surge line pipe with or without swinging were monitored and compared. The temperature differences between the top and bottom of the pipe sections are employed to represent the maximum temperature differences at all the monitored sections. As the surge line swinging, the pattern of temperature distribution and the length of thermal stratification development are different from that in a static. Fluid temperature fluctuation in surge line occur periodically during the fluid temperature rising when the surge line is rotated with the X-axis, and the temperature difference between top and bottom of the surge line is reduced in the same motion mode compared with the static state.

Ge n- and p-FinFETs with different interfacial layer ferroelectric HfZrO x (IL-FE-HZO) gate stacks have been demonstrated systematically by various annealing conditions for the first time. Microwave annealing (MWA) not only shows enhanced FE characteristics but also suppresses the gate leakage and Ge interdiffusion compared with conventional rapid thermal annealing (RTA). While HZO on Al 2 O 3 IL results in paraelectric behavior, HZO on GeO x IL exhibits significant FE. High I on /I off (> 107) and low subthreshold slope (S.S. ∼ 58 mV/dec.) are demonstrated by a Ge nFinFET with a gate length (L g ) of 60 nm and a FE-HZO/GeO x gate stack.

Drug addiction behavior that is established and maintained by psychostimulants has been shown to be associated with the expression of brain-derived neurotrophic factor (BDNF) in the mesolimbic dopamine (DA) system. Cocaine has been used for most prior studies testing this effect of psychostimulants and therefore relatively little is known about its counterpart amphetamine (AMP). To fill this gap, the present study was designed to test whether BDNF mRNA expression levels in the DA terminal regions were changed specifically by d-AMP-induced conditioned place preference (CPP) followed by drug-primed reinstatement. The dose of d-AMP, 1mg/kg, was confirmed to significantly induce CPP. Using this dose, a group of rats was initially subjected to d-AMP CPP, which was followed by entry into an extinction protocol with an additional 3-day withdrawal before a drug-primed reinstatement test was carried out. Following extinction of d-AMP CPP, a lower dose of d-AMP, namely 0.75mg/kg, was able to significantly reinstate CPP. The BDNF mRNA levels in the selected brain areas were determined by real-time polymerase chain reaction (PCR) after the CPP and reinstatement. The BDNF mRNA level in the medial prefrontal cortex (mPFC) was significantly increased after the reinstatement, but not the CPP test. And, none of the other four assessed brain areas showed any change in BDNF mRNA level after d-AMP CPP or reinstatement. These findings support the notion that BDNF is involved in drug-seeking behavior and indicate that d-AMP reinstatement after extinction may be linked to an increase in BDNF mRNA expression in the mPFC.

A distributed Brillouin fiber sensor was used to monitor the health of steel structures. We used this method on two steel beam specimens and longitudinal strain and cracks were detected well under different loads. The difference between the longitudinal strain measured by the distributed fiber sensor and that measured by strain gages is less than 4%. Traditional sensors or transducers that measure the average strain over a small region always miss cracks. The method proposed in this study gives very good results for the detection of cracks and the surrounding strain on a square pipe.

The simulation and visualization of atomic scale behavior during plastic deformation in crystals have been of great interest. Here the authors report a new form of crystal models using stacked drinking straws. The straw model is subjected to indentation pressing while the load-displacement response is measured in situ. Detailed atomistic mechanisms observed during indentation loading are seen to correlate with the overall mechanical response, as well as with theory and previous experiments. Various microscopic features and atomic defects are also incorporated, illustrating the capability of this viable tool for studying nanoscale-mechanical phenomena.

The indentation behavior of layered metal/ceramic nanocomposites was studied. The primary objective was to examine the evolving plastic deformation in the ductile metal constrained by the hard ceramic layers, during indentation cycling with respect to fixed maximum and minimum indentation loads. The model consists of alternating aluminum and silicon carbide thin films on a silicon substrate, with the Al/SiC layered structure being indented by a diamond indenter. The rate-dependent viscoplastic response of Al was specifically taken into account in the numerical model. Plastic deformation in the ductile Al layers continued to occur during the unloading phase of the first cycle, in addition to during subsequent reload/unload processes. Cyclic plasticity resulted in an open load-displacement loop and the indenter continued to move deeper in accordance with each cycle. For the control model of a thick homogeneous Al layer, there was no hysteresis loop and the transient behavior approached stabilization...

The computational modelling of the indentation response of heterogeneous materials is studied using the finite element method. The material system consists of hard particles embedded within a soft matrix. Two material models with exactly the same overall stress-strain characteristics are simulated: one specifically incorporating dispersed elastic particles in an elastic-plastic matrix and the other a simple elastic-plastic continuum having a homogenized constitutive response of the particle-containing material. The material model with particles explicitly included shows a harder response than that of the homogenized model, even when the particle size is much smaller than the indent size. This is primarily due to the local increase in particle concentration directly underneath the indentation, which cannot be easily accounted for in the homogenized model. As a consequence, treating a heterogeneous material as a simple continuum in a straightforward manner appears to be an invalid approach in indentation modelling.

For the first time, Ge CMOS with all thermal processes performed by microwave annealing (MWA) has been realized. The full MWA process is under 390 oC. It significantly outperforms conventional rapid thermal annealing (RTA) process in 3 aspects: (1) Diffusion-less junction: for easily diffused n-type dopant, phosphorous (P), the ion implantation dopant profile after the MWA activation process remains unchanged. (2) Increased C ox and lower gate leakage: the low temperature activation process leads to less Ge out-diffusion during MWA than RTA, suppressing the degradation of gate dielectric/ Ge channel interface. (3) Ultrathin 7.5nm Ni mono-germanide with low sheet resistance (Rs) and contact resistivity: after two-step MWA, a thin mono-NiGe layer was obtained which has larger crystallite size to lower Rs. Ge n- and p-MOSFET were also demonstrated. Compared to conventional RTA, the MWA gives 50% and 24% drive current enhancement for p- and n-MOSFET, respectively. These data show that the low temperature MWA is a very promising thermal process technology for Ge CMOS manufacturing.

The indentation behavior of metal/ceramic nanolayers is studied, with attention devoted to cyclic response under fixed maximum and minimum indentation loads. The primary objective is to examine the evolving plastic deformation in the ductile metal constrained by the hard ceramic layers. The model consists of alternating aluminum (Al) and silicon carbide (SiC) thin films on a silicon substrate, with the Al/SiC layered structure being indented by a diamond indenter. The rate-dependent viscoplastic response of Al is taken into account in the numerical model. It is shown that plastic deformation in the ductile Al layers continues to occur during the unloading phase of the first cycle, as well as during subsequent reload/unload processes. The cyclic plasticity results in an open load-displacement loop, and the indenter continues to move deeper with each cycle. For the control model of a homogeneous Al film, there is no hysteresis loop and the transient behavior soon approaches stabilization, showing repetitive elastic loading/unloading. The modeling results are also compared with cyclic nanoindentation experiments conducted on the same metal-ceramic multilayer system and control specimen.Copyright © 2012 by ASME

Misalignment of chips in three-dimensional (3D) integrated circuit (IC) packages subjects the bonding layer between chips to shear deformation. Chip warpage and thermal effects from chip processing can further compound the problem. In this study we perform a numerical assessment on the shear and thermally-induced deformations in and around the through-silicon vias (TSV) and solder micro-bumps. The 3D finite element model features a TSV/micro-bump bonding structure connecting two adjacent silicon chips, with and without an underfill layer in between. The possibility that the entire solder micro-bump may be transformed into an intermetallic is also considered in this study. We seek to parametrically explore the trend of stress and deformation fields due to misalignment-induced shear deformation and thermal expansion mismatch. Potential for damage initiation in the TSV/micro-bump is examined by the measure of plastic strain accumulation. The existence of an underfill layer around the TSV/micro-bump enhances the overall resistance to shear deformation, although with a higher buildup of local stresses. The TSV and silicon chip are less affected by misalignment than by thermal expansion mismatches.Copyright © 2012 by ASME

An error budget is an analysis tool for the prediction and control of the total error of a machine system for which accuracy is an important measurement of performance. The error budget concept is commonly applied in designing precision machine tools and precision measuring machines and requires application of a combinatorial rule to assess total error which is contributed to by a number of individual error components. No single generally agreed upon combinatorial rule exists for predicting maximum told error that may result from many error components, and precision machine designers often apply empirical formula rules that have evolved from practical experience. Combinatorial rules based on the central limit theorem (CLT) in probability theory and uncertainty interval concept are described in this paper and compared to two empirical formula rules using two precision machine error source examples reported in the literature. It is shown using Monte Carlo simulations that the CLT combinatorial rules and the empirical formulas adequately predict maximum total errors. However, the CLT rules provides a more rigorous methodology than an empirical formula for predicting total error. Moreover, a confidence level associated with the estimated total errors can be specified for error budgeting in precision machine design.

In this chapter attention is directed to patterned thin-film structures, where the film material exists as individual lines of various cross-section geometries. Contrary to the case of continuous films in Chap. 3, the deformation field in the line structure is dominated by the edge effect. In addition, the film segment may be entirely surrounded by one or more different materials so a severely confined condition is in place. The most representative example is the metal interconnects in modern integrated circuits. The interconnect structure is composed of several layers of Cu or Al lines embedded within the dielectric material (traditionally silica glass based, SiOx) on top of the Si substrates. They serve as the connection between the functional elements (transistors) and between the transistors and the outside packaging structure. A schematic illustrating a two-level interconnect structure is shown in Fig. 4.1 (see also Fig. 1.4).

In conjunction with the advancement of microelectronics, the art and technology of electronic packaging have progressed rapidly over the last several decades. Packaging protects the semiconductor or other electronic systems from external environment during manufacturing, assembly, shipping, handling and normal operation. It also serves to facilitate power delivery and thermal management (to maintain the device temperature below certain limits). A package is thus a combination of dissimilar materials in close contact, leading to deformation mismatches and internal stress buildup as a result of thermal and mechanical loads [1–7].

One of the simplest types of physical confinement is a thin continuous film (or blanket film) attached to a thick substrate material. Frequently this is a beginning form for creating micro- and nano-scale systems such as the semiconductor devices. Here the focus is on the constraint imposed by the substrate on the thin film. A numerical example is given below as an introductory illustration.

Based on the optimal fusion algorithm weighted by scalars in the linear minimum variance (LMV) sense, the distributed optimal fusion reduced-order Kalman estimators including predictor, filter and smoother are presented for discrete-time stochastic singular linear systems with multiple sensors and correlated noises. The fusion estimation problem of original high-order singular system is transferred to that of two reduced-order subsystems. They have better precision than any local estimators from every sensor do. The estimation error cross-covariance matrices between any two sensor subsystems are derived for two reduced-order subsystems, respectively. Furthermore, the steady-state fusion estimators are also investigated, which have the reduced online computational burden. A simulation example with three sensors shows the effectiveness.

Recent progresses in atomistic simulations of plastic deformation in nano-scale metallic crystals are presented. Attention is devoted to adjusting the interatomic potential parameters with the objective of gaining fundamental insight into the crystal defect processes in fcc metals. An initial defect is utilized in the molecular statics model to trigger plasticity in a controlled manner. A parametric study is performed by varying the atomic interaction range used in the copper model, such that dislocation slip behavior and/or phase transformation can first be observed without the influence of an unstable surface state of the specimen. We focus on tensile loading along a low-symmetry orientation where single slip prevails upon yielding. When the interaction distance is small, dislocation slip is seen to be the dominant deformation mechanism. A slight increase in the interaction range results in phase transition from the fcc structure to a bcc structure. Re-orientation of the bcc lattice also occurs at later stages of the deformation via a twinning operation. The phase transition mechanism is further enhanced if the nanowire is attached to a flat substrate parallel to the initial close-packed plane. When the atomic interaction range is increased further, the effect of surface stress becomes increasingly important. Plastic yielding occurs in the form of partial slip which creates a stacking fault in the slip plane. The initial point defect plays a less significant role and phase transition during deformation is suppressed. Detailed mechanisms of these atomistic features, as well as their implications to computational simulations of plastic deformation in metallic nanostructures, will be discussed.

Systematic finite element analyses are carried out to model the thermomechanical stresses in on-chip copper interconnect systems. Constitutive behavior of encapsulated copper films, determined by experimentally measuring the stress-temperature response during thermal cycling, is used in the model for predicting stresses in copper interconnect/low-k dielectric structures. Various combinations of oxide and polymer-based low-k dielectric schemes are considered. The evolution of stresses and deformation pattern in the dual-damascene copper, barrier layers, and the dielectrics is seen to have direct connections to the structural integrity of contemporary and future-generation devices. In particular, stresses experienced by the thin barrier layers and the mechanically weak low-k dielectrics are critically assessed. A parametric analysis on the influence of low-k material properties is also conducted. Practical implications in reliability issues such as voiding, interface fracture, electromigration and dielectric failure are discussed.Copyright © 2005 by ASME

By using Langendorff perfused rat heart and enzymatically isolated cardiomyocytes, we investigated the augmented injury effect of iron on the myocardium by hydrogen peroxide and the underlying mechanisms. Cell-permeable iron (Fe-HQ) decreased the contractile amplitude, velocity and end-diastolic cell length of the cardiomyocyte but increased the contents of lactate dehydrogenase (LDH) and creatine kinase (CK) in the coronary effluent and the myocardial malondialdehyde (MDA) while the left ventricular developed pressure (LVDP), +/-dp/dt(max), heart rate and coronary flow showed biphasic alterations. Hydrogen peroxide augmented the injury effect of iron accompanied by increases of coronary LDH, CK release and myocardial MDA content and decreases of LVDP, +/-dp/dt(max), and heart rate. Reduced glutathione could antagonize the injury effect of iron and hydrogen peroxide on the myocardium while dimethyl sulfoxide had no injury effect on the isolated heart. It is suggested that the functional injury of sulfhydryl group containing proteins may be involved in the augmentation of myocardial injury due to the increase of intracellular iron by hydrogen peroxide, but hydroxyl radicals may not.

The purpose of the present study was to explore the biological effects and mechanism of interleukin-2 (IL-2) on the isolated rat heart. The results showed that hrIL-2 increased the number of premature ventricular contraction, heart rate, left ventricular developed pressure, left ventricular end-diastolic pressure and coronary flow in the isolated perfused rat heart. Heat inactivated hrIL-2 had no effect on the heart. Pretreatment with ryanodine canceled the positive effects of hrIL-2 on left ventricular developed pressure, left ventricular end-diastolic pressure and coronary flow but had no effects on arrhythmogenesis and tachycardia by hrIL-2. Pretreatment with nifedipine or low extracellular calcium abolished the arrhythmogenic effect of hrIL-2 and attenuated partially the augment of heart rate, left ventricular developed pressure, left ventricular end-diastolic pressure and coronary flow. It suggests that the cardiac activity of hrIL-2 depended on the integrity of its spatial structure and transmembrane influx Ca2+ and intracellularly stored Ca2+ were involved in the cardiac activity of hrIL-2.

Objective. To provide a real useful application system for the HRV research. Method. The acquisition, detection and analysis system of HRV signal was set up based on Windows 95. The system analyzes the HRV signal with statistic method in time domain and power spectrum in frequency domain. And the power spectrum array was also introduced into the analysis. HRV signals of some healthy persons and some patients were detected and analyzed. Result. The HRV characteristic is much more obvious in the diabetics patients. Conclusion. The system is useful in HRV signal analysis and cardiovascular research.

In the present study, the relationship between the blockade of kappa-opioid receptor and ischemic preconditioning (IP) was examined and the effect of IP and prolonged ischemia on levels of dynorphin A1-13 (Dyn A1-13) in cardiac muscle in isolated perfused rat heart was investigated. The results are as follows: (1) IP reduced the severity of ischemia/reperfusion arrhythmia (P0.05) and infarct size (P0.01), but had no significant effect on heart rate and coronary flow (P0.05); (2) MR2266, kappa opioid receptor antagonist, reduced the severity of ischemia/reperfusion arrhythmia (P0.05) and infarct size (P0.01), and also enhanced the recovery of coronary flow, but had no significant effect on heart rate (P0.05); and (3) prolonged ischemia decreased the levels of Dyn A1-13 (P0.05), which was more marked in the unpreconditioned hearts. The results suggest: (1) MR2266 can "mimic" cardioprotective effect of IP in reducing the severity of arrhythmias and limiting infarct size of cardiac muscle; (2) ischemia causes release of endogenous kappa opioids, which can be attenuated by IP; and (3) the cardioprotective effects of IP in rat heart involves endogenous kappa opioids.

To extend the investigation of tail-pinch induced behavioral changes, rats performing on a differential reinforcement of low rates of 10 sec (DRL10), a fixed-interval of 60 sec (F160), and a fixed-ratio of 20 (FR20) schedules were exposed to a paper clip applied to the tail. While a 10 min tail-pinch conducted 1 hr before operant sessions significantly altered the DRL10 behavior, this stressor had little effect on either F160 or FR20 responding. Marked DRL10 behavior performance changes following tail-pinch included increases in the number of lever presses, decreases in the number of the reinforcers, and disruption in the frequency distribution of inter-response times (IRT). These DRL10 operant deficits were diminished when the subject received a tail-pinch pretreatment followed by d-amphetamine treatment (0.2 and 2.0 mg/kg). In combination with biochemical data from others, the present results suggest that catecholamine systems are involved in modulation of DRL10 behavior following tail-pinch.

Intracellular recordings were made from bullfrog sympathetic ganglion cells to elucidate effects of 2-n-butyl-1-(4-methylpiperazinyl)-5,6-methylenedioxyindene.2 HCl (TN-871) on synaptic transmission. TN-871 at 30 nM augmented cholinergic nicotinic fast excitatory postsynaptic potentials (fast EPSPs), whereas the drug at 3 microM reversibly depressed them, without affecting acetylcholine-induced depolarizations. TN-871 did not affect active and passive electrical properties of the ganglion cells. The quantal analysis method was applied to the fast EPSPs in a 0.54 mM Ca2+/7.56 mM Mg2+ Ringer's solution. The mean quantal content was significantly increased by TN-871 at 30 nM but significantly decreased at 3 microM. TN-871 at 300 nM either increased or decreased the mean quantal content. The mean quantal size of the fast EPSPs was not changed by TN-871 at the concentrations examined. Fast EPSPs in a 0.99 mM Ca2+/4.86 mM Mg2+ Ringer's solution were not affected by nicardipine, but were inhibited in amplitude by omega-conotoxin in a concentration-dependent manner. It is likely that TN-871, in high concentrations, might block omega-conotoxin-sensitive N-type calcium channels in the presynaptic terminals. These results indicate that TN-871 modulates transmitter release from preganglionic nerve terminals without changing the postsynaptic sensitivity of the ganglion cells to ACh.

We report the within-person, between-person, and methodological variances of a number of chemical analytes for free-living, middle-aged adults who participated in the Atherosclerosis Risk in Communities Study's Intraindividual Variability Study. The Atherosclerosis Risk in Communities Study is a National Institutes of Health-sponsored multicenter study of atherosclerotic risk factors. In the Atherosclerosis Risk in Communities Study and its Intraindividual Variability Study, concentrations of the following 12 chemical analytes were measured in serum from fasting individuals: sodium, calcium, potassium, creatinine, albumin, total protein, magnesium, phosphorus, urea, insulin, glucose, and urate. The analytes are listed in order of the increasing reliability coefficient (ie, the fraction that between-person variance represents of the total observed population variance), which ranged from .59 for sodium to .91 for urate. The reliability coefficient is a strong predictor of the possibility of finding statistical correlations between measured analyte concentrations and disease occurrence in an epidemiological study like the Atherosclerosis Risk in Communities Study. The within-person variance and methodological variance are also useful in computing confidence intervals for sequential laboratory test results in patients and evaluating limits for internal quality control and proficiency testing programs.

Intracellular calcium concentration ([Ca2+]i) of the rabbit eye suprachoroid was measured with microfluorophotometry using fura-2. Adenosine-5'-triphosphate (ATP) 1-100 microM, added to a perfusing solution, elicited an increase in [Ca2+]i of the suprachoroid. This action of ATP was inhibited when preparations were perfused with a nominally zero Ca2+ Krebs solution or a high magnesium Krebs solution. The [Ca2+]i-increasing action of ATP was attenuated either by lowering temperature or by a phospholipase C inhibitor, compound 48/80. These results indicate that extracellular Ca2+ is necessary to the ATP action and also suggest that the ATP action may be mediated by the intracellular signal transduction which exerts a Ca(2+)-release from intracellular Ca(2+)-store sites. The potency order of ATP-related purine nucleotides was ATPor = ATP-gamma-Sadenosine-5'-diphosphate (ADP). Adenosine-5'-monophosphate (AMP) and adenosine were not effective. It is concluded that P2-purinoceptors exist on the surface of the suprachoroid and are involved in mechanisms underlying the ATP-induced increase in [Ca2+]i of the suprachoroid.

Recent epidemiologic studies found that there is a strong association of hemostatic factors with ischemic heart disease. The Atherosclerosis Risk in Communities (ARIC) Intraindividual Variability (IIV) Study was conducted to estimate the various components of variation in hemostasis factors measured in the ARIC Study and to estimate the measures of repeatability of these factors. A total of 39 subjects (16 men, 23 women) were studied. Each had blood collected three times, with a 1- to 2-week interval between each visit. The contributions of between-person variability, within-person (biologic) variability, and processing and assay variability were estimated. Then the reliability coefficient R was estimated as the proportion of total variance accounted for by between-person variance. The reliability coefficient can be interpreted as the correlation between measures made at repeat visits. Among the various analytes, the reliability coefficients were quite high for activated partial thromboplastin time and plasma factor VIII (R = 0.92, 0.86, respectively). Low repeatability was obtained for antithrombin III activity and protein C (R = 0.42, 0.56, respectively). The lack of repeatability for these variables derives mostly from the processing (field center and laboratory) variation. Other analytes--fibrinogen, plasma factor VII, and von Willebrand factor--were intermediate in repeatability. In comparing the analyte-specific high-level to low-level groups, no substantial difference of within-person plus method coefficient of variation between the two groups was found for any analyte except for factor VIII, whereas the corresponding variance components for most analytes were higher for the higher analyte level. Reliability coefficients from this ARIC IIV study are generally higher than those found in other studies, and this is related to the relative variations in populations studied and to the time between measurements.

Because the pathogenesis of osteosclerosis in hypervitaminosis D is still not well elucidated, the authors experimentally studied hypervitaminosis D3 in 66 rabbits by injecting different doses of vitamin D3. Contact radiographs of bone specimens showed various signs of osteosclerosis, including dense epiphyses and metaphyses, thickened bony articular surfaces, dense metaphyseal bands, modeling defects at the metaphysis, and dense and thickened cortical bone. The corresponding pathologic sections showed that conspicuous metastatic calcification coated the trabeculae and filled bone marrow cavity and caverns in the original but porotic cortical and periosteal new bone. Rather than being resorbed, the metastatic calcifications were embedded in a thick layer of newly formed bone 6 to 14 weeks after vitamin D3 withdrawal. This study suggests that in hypervitaminosis D3, the osteoblasts and bone marrow undergo degeneration, leading to necrosis and calcification. After vitamin D3 withdrawal, osteoblasts reappear and become overactive, leading to overossification.

Room-temperature ferromagnetism was observed in Ge nanostructures deposited on polystyrene nanospheres. Various Ge layers (3, 5, 10, and 20nm) were deposited on different nanospheres (20, 30, 50, and 100nm in diameter). The magnetization in Ge nanostructures was influenced by both the thickness of Ge layers and the size of nanospheres. Maximum magnetization (360emu∕g) and magnetic moment (4.7μB∕Ge) were observed in the sample with a 5nm thick Ge layer on nanospheres with a diameter of 20nm. The ferromagnetism in Ge nanostructures was attributed to both the quantum size effect and the junctions among nanostructures.