cssi/SciSciGPT-SciSciNet huggingface dataset:
The design, construction, and initial characterization of an ultra-low-background gas-proportional counting system

Over the past several years, the Pacific Northwest National Laboratory (PNNL) has developed an ultra-low-background proportional counter (ULBPC) technology. The resulting detector is the product of an effort to produce a low-background, physically robust gas proportional counter for applications like radon emanation measurements, groundwater tritium, and 37Ar. In order to fully take advantage of the inherent low-background properties designed into the ULBPC, a comparably low-background dedicated counting system is required. An ultra-low-background counting system (ULBCS) was recently built in the new shallow underground laboratory at PNNL. With a design depth of 30 m water-equivalent, the shallow underground laboratory provides approximately 100× fewer fast neutrons and 6× fewer muons than a surface location. The ULBCS itself provides additional shielding in the form of active anti-cosmic veto (via 2-in-thick plastic scintillator paddles) and passive borated poly (1 in.), lead (6 in.), and copper (~3 in.) shielding. This work will provide details on PNNL’s new shallow underground laboratory, examine the motivation for the design of the counting system, and provide results from the characterization of the ULBCS, including initial detector background.
Angular dependence of high-transverse-momentum inclusive π0 production in π±p and pp interactions

Abstract We have measured the inclusive π0 production at high transverse momentum from both pion and proton beams at 100 and 200 GeV/c. Salient characteristics are a wide plateau in the cm angular distribution and evidence for scaling in both πp and pp interactions. The π±p→π0X cross sections fall less steeply with x| = (p|/pmax)cm, and peak at x| = 0.14, in contrast to the pp→π0X cross sections, which peak at x| = 0.
God in the process: Is there a place for religion in conflict resolution?

There is a growing demand for religion and spirituality in conflict resolution processes. Is this dangerous or praiseworthy, and how should we respond? The authors reviewed literature from conflict resolution, psychology, and law. They conclude that faith, religion, spirituality, and values: (1) can have a safe place in the process; (2) need to be a subject of expertise for conflict resolvers; and (3) should be understood through the self-awareness work of being an ethical practitioner, regardless of their beliefs. The authors explore the implications of this for the self-determination of parties and the legitimacy of third-party roles.
Novel approach to self-sensing actuation

Self-sensing approaches for controlling piezoelectric materials thus far have been composed of slight variations on a theme; the theme being a linear bridge technique for extracting the self-sensing signal. Linear bridge-based self- sensing however has always been plagued with problems of impedance mismatching, drift, and instability, all due to the nonlinearities inherent in piezomaterials. Additionally, all past self-sensing research has been limited to strictly ac sensing applications, hence the abundance of vibration suppression papers. We propose a novel self-sensing technique which shows promise in reducing most if not all of these problems. The approach dubbed OBSS (observer based self- sensing) is akin to state estimation techniques in that is uses electric field and electric displacement information coupled with the linear piezoelectric constitutive relations to estimate the material's stress and strain states. Additionally, since most piezomaterials exhibit significant hysteresis, a real-time compensation method using the generalized Maxwell slip hysteresis model must be employed to minimize this nonlinear effect. Theoretical development and experimental validation of the OBSS technique is presented.
A computer animation representing the molecular events of G protein-coupled receptor activation (case study)

The molecular events involved in the activation of G protein-coupled receptors, represent a fundamental biochemical process. These events were selected for animation because the mechanism involves both a ligand-receptor conformational shape change, and an enzyme-substrate conformational shape change. Expository animation brought this biochemical process to life.
Depression in Family Members Caring for a Relative With Alzheimer's Disease

The reformulated learned helplessness model of depression was tested in a study of families caring for relatives with Alzheimer's disease who did not participate in family support groups or have access to respite care. Family members who identified themselves as major caregivers, ie, those providing daily assistance to the patient, received a clinical psychiatric interview, the Beck Self-Report Depression Scale, and a modified Hammen and deMayo Attributional Style Questionnaire. The results showed that 55% of major caregivers, primarily spouses, living with an older relative with dementia experienced clinical depression. Depressed caregivers were more likely to perceive a lack of control over their situation than those who were not depressed. Contrary to the reformulated learned helplessness hypothesis, they did not perceive their situation to be the result of internal, stable, and global attributions. The results suggest the need to study depression in ecologically stressful natural settings and to develop effective clinical intervention strategies.
Steady state of stiff linear kinetic systems by a Markov matrix method

Abstract The absence of detailed balance in systems containing pseudo-first-order reactions can cause the evaluation of steady-state concentrations to be a difficult computational problem. if the rate constants differ by many orders of magnitude, direct solution for these concentrations from the matrix of rate constants is not practical. The embedded Markov chain generated by the state-changes of one molecule has a transition matrix whose better separation of eigenvalues makes it more suitable for analysis than the matrix of rate constants. Solution for an eigenvector of this matrix by the method of inverse iteration provides an efficient means for obtaining steady-state concentrations.
Bounding Fitting Heights of Character Degree Graphs

ofG,written G ,isthegraphwhosevertexsetisρ G .Twoverticespandqinρ G areadjacentifthereis some degree a∈ cd G where pqdivides a. These graphs have beenstudiedinseveralplaces.Thebestsourcesforgeneralinformationaboutthese graphs are Theorem 14 of [2], Chapter 30 of [3], and Sections 18and19of[10].In[8],adegreegraph wassaidtohave
Improving system sensitivity via surplus controller capacity

Abstract In this paper a linear plant with variable characteristics is considered. It is assumed that the plant is driven optimally by an open-loop controller. For a particular task and a nominal plant characteristic the controller is assumed to have a surplus capacity (in the optimal sense). This surplus capacity is used to minimize the effects of fluctuations in the plant characteristics about the nominal. Three criteria are formulated for optimally using the controller surplus capacity. Solutions to the three cases are derived and compared. The analysis provides insight into problems of optimal control containing a parameter.
Coronary angioplasty: a therapeutic option for symptomatic patients with two and three vessel coronary disease.

Abstract Coronary angioplasty is a widely applied revascularization procedure for patients with multivessel coronary artery disease. However, follow-up in this patient subgroup is relatively limited. From 1983 to 1986, coronary angioplasty was performed in 349 and 121 patients with, respectively, two- and three-vessel coronary disease with a primary success rate of 83 and 88%. The in-hospital mortality rate was 2.8% (13 of 470 patients). Complete revascularization was achieved in 128 patients. Among the 397 patients with a successful outcome, 373 (94%) were followed up ≥ 1 year; 79% were free of death, nonfatal myocardial infarction or the need for coronary bypass grafting, and 82% of patients had symptomatic improvement by at least one angina functional class. A second coronary angioplasty procedure was required in 13% of patients. After a mean follow-up period of 27 months, an increased incidence of coronary bypass grafting was noted in patients with incomplete versus complete revascularization (16 versus 7%, p In conclusion, coronary angioplasty can be performed with a high initial success rate and marked symptomatic improvement in patients with multivessel coronary disease. However, in this group's experience, the majority of patients selected for coronary angioplasty with multivessel coronary disease will have incomplete revascularization that can be predicted in the majority of patients before the procedure. The risk of subsequent cardiac events over 2 years of follow-up is small but is increased in patients with incomplete revascularization.
Iteration theorems for families of strict deterministic languages

Abstract Two iteration theorems, one for strict deterministic languages of degree n , the other for simple deterministic languages, are presented. Examples demonstrating the use of these theorems are also given.
Review: effect of bimetal interface structure on the mechanical behavior of Cu–Nb fcc–bcc nanolayered composites

This article reviews the growing body of work over the past decade investigating the effect of interface crystallographic character and resulting local interface structure on the mechanical behavior in bimetallic nanolayered composites. It has been shown that nanolayered composites exhibit enhanced strength, thermal stability, radiation damage tolerance, and resistance to shock deformation in comparison to their coarse-grained constituents. These unique behaviors are attributable to the high density of interfacial content, as well as the local interface structure and its influence on mechanically or irradiation-induced defects. Here, we cover recent literature on Cu–Nb nanolayered composites synthesized via different pathways including physical vapor deposition and severe plastic deformation techniques such as accumulative roll bonding. By altering the synthesis method, we can produce materials with similar chemical composition and layered morphology, while varying only the crystallographic character of the interface as defined by the orientation relationship and interface plane. This capability, in turn, opens an unprecedented opportunity for systematic investigation of the local interface structure on subsequent behavior, while keeping all other variables constant. We begin with a discussion of interface structures that develop as a function of their processing path. We then follow with the effects of interface structure on dislocation nucleation and deformation twinning. Next, we discuss interface effects on mechanical behavior at quasi-static ambient conditions and later under extreme strains, strain rates, and temperatures. Taken together, these examples provide a strong indication that interface structure matters. The exciting implication is that bimetal interfaces can potentially be engineered for optimal material performance.
Infrared Fiber Technology: Its Promise and Status

Optical fibers with attenuations much lower than those attainable in present-day silicate waveguides are possible in theory if mid-infrared operating wavelengths are used. The loss mechanisms, materials, and problems inherent in obtaining such fibers are discussed. Among several candidates, heavy metal fluoride glasses are suggested as being must suited to low and moderate loss fiber applications in the 2-5 micrometer spectral region.
Fixed-point implementation of active disturbance rejection control for superconducting radio frequency cavities

A fixed-point implementation of the previously explored active disturbance rejection control (ADRC) for superconducting radio frequency (SRF) cavities is presented in this paper. The developed fixed-point algorithm is very suitable for being implemented on a field programmable gate array (FPGA) allowing high sampling rate (>20 MHz), which may be needed in special applications. The design tradeoffs are discussed as well to ensure its implementation on a low end FPGA with limited resources. Through both simulations and hardware tests, it is demonstrated that the fixed-point algorithm provides performance as good as the floating-point algorithm.
Optimal input signals for parameter estimation in dynamic systems--Survey and new results

This paper surveys the field of optimal input design for parameter estimation as it has developed over the last two decades. Many of the developments covered are only recent and have not appeared in the open literature elsewhere. After a brief introduction, the paper discusses the historical background of the subject both in the engineering and in the statistical literature. The concepts of optimality and input design are then discussed, followed by a derivation of the Fisher information matrix for multiinput multioutput systems with process noise. The design procedures are divided into the categories of time-domain methods and frequency-domain methods, with the former being more general, but also more time consuming (computationally). Several extensions to state constraints, continuous-time systems, etc., are discussed. A number of examples are given to illustrate the nature of optimal inputs. The results on time-domain synthesis with state constraints and their relationship to "dual control" are new.
Balloon-borne photoionization mass spectrometer for measurement of stratospheric gases.

A balloon-borne photoionization mass spectrometer used to measure stratospheric trace gases is described. Ions are created with photons from high-intensity krypton discharge lamps and a quadrupole mass analyzer is employed for ion identification. Differential pumping is achieved with liquid helium cryopumping. To insure measurement of unperturbed stratospheric air, the entire system is contained in a sealed gondola and the atmospheric sample is taken some distance away during descent. The photoionization technique allows the detection of a low ionization potential constituent, such as nitric oxide, at less than a part in one billion in the presence of the major atmospheric gases and their isotopes. Operation of the mass spectrometer system was demonstrated during a daytime flight from Palestine, Texas on 26 April 1977. The sensitivity achieved and the unique selectivity afforded by this technique offer a capability for trace constituent measurement not possible with the more conventional electron impact ionization approach.
Modeling potential future individual tree-species distributions in the eastern United States under a climate change scenario: a case study with Pinus virginiana

Abstract We are using a deterministic regression tree analysis model (DISTRIB) and a stochastic migration model (SHIFT) to examine potential distributions of ∼66 individual species of eastern US trees under a 2×CO2 climate change scenario. This process is demonstrated for Virginia pine (Pinus virginiana). USDA Forest Service Forest Inventory and Analysis data for more than 100 000 plots and nearly 3 million trees east of the 100th meridian were analyzed and aggregated to the county level to provide species importance values for each of more than 2100 counties. County-level data also were compiled on climate, soils, land use, elevation, and spatial pattern. Regression tree analysis (RTA) was used to devise prediction rules from current species–environment relationships, which were then used to replicate the current distribution and predict the potential future distributions under two scenarios of climate change (2×CO2). RTA allows different variables to control importance value predictions at different regions, e.g. at the northern versus southern range limits of a species. RTA outputs represent the potential ‘environmental envelope’ shifts required by species, while the migration model predicts the more realistic shifts based on colonization probabilities from varying species abundances within a fragmented landscape. The model shows severely limited migration in regions of high forest fragmentation, particularly when the species is low in abundance near the range boundary. These tools are providing mechanisms for evaluating the relationships among various environmental and landscape factors associated with tree-species importance and potential migration in a changing global climate.
The Anatomical Determinants for the Design of Intracardiac Mapping and Ablation Catheters

An important factor in the efficient and successful completion of the ablation procedure is the design characteristics of the mapping/ablation catheters. These procedures are often hampered by the inability to maneuver the catheter to the desired location, in part because the catheters only have a single plane deflection capability and are not designed for the specific cardiac anatomical structures that contain the arrhythmogenic substrate. Single and Biplane Deflectable Catheters: Using measurements taken from six normal human cadaver hearts, ablation catheter design characteristics are presented for posterior, posterior septal, lateral, and posterior lateral pathways for retrograde and transseptal approaches. Three catheter designs based on anatomical characteristics were also evaluated. Pigtail Catheter: This catheter adapts to the atrial side of the mitral ring and improves positioning and stability for mapping and ablation of left-sided accessory pathways. Loop Catheter: This catheter is positioned at the perivalvular tricuspid ring and provides simultaneous mapping and ablation capabilities without the need to move the catheter or the need for additional catheters. Rotating Tip Catheter: The tip of this catheter is made up of three elongated teeth, which were curved 120 degrees apart into the rotating tip electrode. This electrode was designed to negotiate the surfaces of the atrial and intraventricular chambers. It is capable of discrete movements and has a large electrode-tissue contact area for the ablation of atrial and ventricular arrhythmias. Catheter designs presented in this article are based on the ability of the catheter to adapt to the anatomical location of the arrhythmogenic tissue as well as the maneuverability of the catheter's mapping and ablation electrodes. An anatomical approach to the design of ablation catheter technology is likely to reduce the x-ray radiation exposure for patient and operator, and may further increase the success rate of the procedure.
Enthalpy and Entropy in Ring Closure Reactions

Abstract The strain and entropy effects of the lactone formation from ω-bromoalkane-carboxylate ions in ring sizes 3 to 23 is reevaluated. We find that Δ H ‡ is the largest contributor to the observed rates (Δ G ‡ ) for ring sizes 3 to 6, while − T Δ S ‡ has little influence, − T Δ S ‡ has more effect on the observed rates for ring sizes 8 and larger.
Physical activity across the curriculum (PAAC): rationale and design.

Abstract Background Over the years schools have reduced physical education and recess time in favor of more academic instruction. Due to the drastic rise in obesity levels among children, some states have begun to mandate minimum amounts of physical activity (PA) that school children receive, causing schools to find alternative methods for increasing PA levels. Physical Activity Across the Curriculum (PAAC) is a 3-year randomized clinical trial incorporating moderate-intensity PA in elementary schools to reduce childhood obesity. This paper describes the rational, design, and methods of the PAAC intervention study. Methods Twenty-two elementary schools were randomized to either a control or intervention condition. In schools randomized to the intervention condition (PAAC), regular classroom teachers were taught how to incorporate PA into standard academic lessons. Teachers were asked to accumulate 90–100 min/week of PAAC each week through out the 3-year study period. Schools randomized to the control group did not alter their teaching methods. Direct observation of PA levels in the classroom was collected weekly. Height and weight was measured twice a year to calculate BMI. Results Two years of the intervention have been completed and only one school has left the study. The remaining 21 schools are participating in the final intervention year. Conclusions The results from the PAAC intervention may provide schools with an alternative method to increase PA levels in children and reduce childhood obesity.
Modulation-enabled tapered remote coupler: all-optical communication on and off chip

The "Modulation-Enabled Tapered Remote Coupler" (METRoC) is introduced targeting the integration of on-chip and off-chip optical interconnects. With Moore's law scaling of CMOS critical dimensions, the computing power of modern microprocessors has grown rapidly. Future multi-core chips will demand aggregate on- and off-chip bandwidths in the TBytes/sec regime. However, metal on-chip global interconnections and off-chip communications do not scale commensurately with the CMOS device sizes, resulting in challenges to meet the growing bandwidth requirements within acceptable power budgets. Optics is a potential solution to replace the fundamentally limited electrical interconnects. Recent advancements in optical and optoelectronic component fabrication and manufacturing processes may enable implementation of optical interconnects at the chip-scale. An optical solution that seamlessly integrates the two domains is highly desirable. The METRoC is proposed as a compact optical interconnect fabric that obviates the need for opto-electronic and electrooptic conversions when signals propagate between the on-chip and off-chip domains. Multiple quantum well (MQW) devices are chosen as the optical modulators and photodetectors. The key aspect of METRoC is the modulationenhanced prismatic structures embedded in waveguides, which enable the direct coupling from the integrated MQW devices to the intra-chip guided-wave fabrics. Additionally, tapered remote couplers can provide free-space interconnections between chips or remote regions on-chip. Both coupling structures have small footprint areas and hence are projected to provide high bandwidth densities. The fabrication process is compatible with silicon CMOS processes. The coupling fabric can also be used to optically interconnect two silicon die within a multichip module.
On the SO(7) symmetry of the SO(8) monopole and quadrupole pairing model

Abstract The SO(7) D-pairing symmetry of the SO(8) monopole and quadrupole pairing model is shown to be unusual in that there is no corresponding group generated only by number-conserving operators. Rather, the SO(7) symmetry is manifested in terms of number-conserving operators only by taking a particular combination of the Casimir operators appropriate for the other subgroup chains.
Sodium and potassium concentrations in bile from human gallbladders.

SummaryMeasurements of sodium, potassium, pH, total solids and pigment in human gallbladder bile indicate wide variations. Potassium is present in higher concentrations than in extracellular fluids. The resorptive power as measured by pigment failed to correlate with the increase in potassium concentration and total solids.
The PTEN-AKT3 Signaling Cascade as a Therapeutic Target in Melanoma

Melanocytes undergo extensive genetic changes during transformation into aggressive melanomas. These changes deregulate genes whose aberrant activity promotes the development of this disease. The phosphoinositide-3-kinase (PI3K) and mitogen-activated protein (MAP) kinase pathways are two key signaling cascades that have been found to play prominent roles in melanoma development. These pathways relay extra-cellular signals via an ordered series of consecutive phosphorylation events from cell surface throughout the cytoplasm and nucleus regulating diverse cellular processes including proliferation, survival, invasion and angiogenesis. It is generally accepted that therapeutic agents would need to target these two pathways to be an effective therapy for the long-term treatment of advanced-stage melanoma patients. This review provides an overview of the PI3 kinase pathway focusing specifically on two members of the pathway, called PTEN and Akt3, which play important roles in melanoma development. Mechanisms leading to deregulation of these two proteins and therapeutic implications of targeting this signaling cascade to treat melanoma are detailed in this review.
The Impact of Employee's Satisfaction on Company's Well-being and Sustainability of the Company in the Long Run

Nowadays, many business owners and companies realize that employees have now become one the most important assets of a company; their level of happiness and satisfaction will directly impact their working performance and affect company's overall performance and sustainability. It is crucial for companies to keep employees satisfied because it is one of the critical components to success. This article will discuss the factors that affect employees' satisfaction and the impact of their satisfaction to the company's well-being and sustainability of the company in the long run.
Beyond the physical: A qualitative assessment of the burden of symptomatic uterine fibroids on women's emotional and psychosocial health

Abstract Objective To qualitatively assess the burden of uterine fibroids on women's emotional health. Methods Sixty women (n = 60) with symptomatic uterine fibroids were recruited from an urban academic medical center and community-based organizations. Women completed qualitative, semi-structured interviews and demographic surveys. Interviews were recorded and transcribed verbatim. Using a grounded theory approach, three coders independently identified major themes and subthemes that emerged from the interviews. Results The kappa among coders was 0.94. The mean age of participants was 43.0 ± 6.8. 61.7% of participants self-identified as African-American, 25.0% as Caucasian, 8.3% as Hispanic and 5.0% as Asian. Most participants exhibited a significant emotional response to their fibroids, including fear, anxiety, anger, and depression. Half of the women felt helpless and believed that they had no control over their fibroids. Many women possessed a negative self-image and cited concern over appearing less attractive, which led to difficulties becoming intimate. Several women felt that they lacked substantial support to help them deal with these issues. Conclusion In addition to the known high prevalence and severe physical impact of uterine fibroids, there is a significant psychological impact on women. Many women lack support to help them deal with these issues and very few seek help from a mental health professional. There is an opportunity and a need for the mental health community to address the concerns in this population, in order to improve psychological health and quality of life in patients living with this chronic condition.
Rigid and Flexible Low Reynolds Number Airfoils

Issues related to the design of low Reynolds number airfoils, such as the thickness, camber, and surface proe les, are investigated. To contrast the issues involved, NACA 0012 and CLARK-Y, two well-known airfoils, a recently proposed low Reynolds number airfoil S1223, and a modie ed airfoil UF, are compared under varied Reynolds numbers and angles of attack. These airfoilsrange from 0% (NACA 0012)to 8.89%(S1223)camber, and from 6% (UF)to12.9%(CLARK-Y)thickness,and allowusto makea broadcomparison of thelift-and-drag characteristics with varying Reynolds numbers, from 7.5 £ 104 to 2.0 £ 106. Furthermore, the concept of a e exible airfoil is assessed in an unsteady, low Reynolds number environment. To facilitate the present study, we have employed techniques treating either inviscid or coupled inviscid/boundary-layer e ows around rigid airfoils, as well as a moving boundary technique to handle an elastic, massless membrane in a portion of the upper airfoil surface. The results show that within the range of Reynolds numbers and airfoil shapes, increased camber and reduced thickness provide more favorable lift-and-drag characteristics when the Reynolds number becomes lower. The results also indicate that a e exible proe le yields better overall performance than a similar rigid proe le in an oscillating freestream.
Hypotension induced by central hypovolaemia and hypoxaemia

Summary. Our question was whether the reduced orthostatic tolerance that accompanies hypoxaemia in some (not all) subjects might be associated with an abnormally large release of adrenaline. Eight normal young men were exposed to lower body negative pressure (LBNP) at —30 to —40 mmHg while breathing air or 10% O2 in N2. Four subjects developed hypotension and bradycardia whenever LBNP was applied during hypoxaemia; four showed a rise in heart rate and stable blood pressure. During normoxia plasma adrenaline concentration did not rise during LBNP in any subject, nor during hypoxaemia plus LBNP in the subjects who remained normotensive. In the four men whose heart rates and blood pressures fell during LBNP with hypoxaemia, adrenaline rose markedly, reaching 200–1600 pg ml-1. All subjects showed similar elevations in noradrenaline concentration during LBNP in both normoxia and hypoxaemia. The results suggest that reduced tolerance to central hypovolaemia during hypoxaemia could stem from known vasomotor and cardiac effects attending high plasma concentrations of adrenaline.
Positions of cations and molecules in zeolites with the chabazite framework I. Dehydrated ca-exchanged chabazite

Abstract Chabazite from Bozen, Tyrol, was ion-exchanged with CaCl2 solution to Ca1.9Al3.8Si8.2O24.nH2O. After de h ydration at 320°C for 1 day, the crystal structure (R3m a 9.442(2) A α 93.09(1)°) was determined at room temperature. Most Ca atoms (refined to 1.88) are displaced into the large cavity from the center of a 6-ring and lie at 2.33A to three O(4) and 2.78 to three O(3). The center of the ditrigonal prism contains 0.1 Ca apparently at 2.8A to six O(4). All cations have O(4) as nearest neighbors leaving the other framework oxygens undersaturated. The TO bond lengths increase ∼0.08 A per unit charge of undersaturation. The cation distribution and cell dimensions differ from those determined earlier for Ca-exchanged chabazite from Benton County, Oregon, which was dehydrated at 360°C for 4 hr.
Treatment of endocarditis due to Proteus species: a literature review

Endocarditis due to Proteus species is very rare. We report a case of endocarditis due to Proteus mirabilis that was successfully treated with ampicillin and gentamicin, and review the treatment regimens of previously published cases of Proteus endocarditis.
Useful Instruction for Practical People: Early Printed Discussions of the Slide Rule in the US

Printed accounts of the appearance and use of various forms of slide rule appear in a variety of 18th and early 19th American printed sources. Based largely on British work, these texts reveal both confidence in the practical potential of the instrument and the slow diffusion of the device.
Decrease of sensitivity to ultraviolet radiation of Streptococcus faecalis grown in media supplemented with 6-azathymine, an analog of thymine.

Streptococcus faecalis was grown in basal medium supplemented with thymidine, as well as two levels of azathymine, a non-inhibitory concentration and a level that resulted in 50% inhibition of growth. After incubation for 20 hr at 37 deg , the cells were harvested by centrifugation, washed once with saline, resuspended in saline, and adjusted to approximately the same turbidity. Ten ml of each suspension were placed in petri dishes and irradiated for various intervals of time with a 15-W General Electric germicidal lamp from a distance of 60 cm. The viability before and after irradiation was determined by serial dilution of the cuIture and plating of aliquots on micro-assay cuiture agar, using the surface-drop method. The agar pfates were incubated in the dark for 18 hr at 37 deg and the number of evolved colonies were counted. There was no significant difference in the number of survivors after ultraviolet irradiation of cells grown in the absence of azathymine or in the presence of non-inhibitory levels of the compound. However, cultures grown in the presence of an inhibitory concentration of azathymine showed a 10-fold increase in resistance to the lethal effects of ultraviolet irradiation after 4 min of irradiation. (C.H.)
Electron transfer induced deprotonation of α- and β-pinene: Evidence for ring-closed vinylcyclobutane radical cations

Abstract Electron transfer from α- ( 1 ) or β-pinene ( 2 ), to 2,3,5,6-tetrachlorobenzoquinone generates radical cations, which are rapidly deprotonated by the semiquinone radical anion. (1S,5S)- 2 is converted to (1S,5S)- 1 and (1R,5R)- 1 yields a dehydrogenation product, verbenene, (1R,5R)- 9 with essentially quantitative retention of optical activity. The results support chiral, “ring-closed” radical cation structures in which the allylic-quaternary cyclobutane CC bond retains a significant degree of bonding.
Wear mechanisms of UHMWPE in total joint replacements

Abstract The wear of ultra-high molecular weight polyethylene (UHMWPE) has become a major focus regarding the long-term clinical performance of total joint replacements. Clinical retrieval analysis has revealed the existence of two distinct wear mechanisms that are operational in both total hip and total knee replacements. While the majority of the wear debris produced from the acetabular component is less than a micron in size and often particulate or fibrous in shape, much larger thin flakelike wear debris is produced from the tibial component. Two theoretical wear models that are based on the scale of intimate asperity interactions are proposed to account for the observed differences in hip and knee wear. Cyclic plastic strain accumulation is identified as the common cause for wear debris generation in both hip and knee replacements. In the case of acetabular cup wear, the scale of plastic deformation is limited to the sites of intimate micro-asperity contacts and the wear rate is defined by a critical strain criterion. In the case of tibial component wear, however, plastic deformation spreads into the subsurface to the site of macro-asperity contacts, and material can be removed by subsurface cracking and delamination. In both cases, the wear rate is strongly affected by the ultimate tensile strength and breaking elongation of the UHMWPE material.
Impact of Plateaued Surfaces on Tribological Performance

Plateaued surfaces are surfaces that have been machined to simulate those that result from normal running in and are said to have advantages over conventional or non-plateaued surfaces. However, the evidence is lacking. This study evaluates the tribological performance of plateaued and non-plateaued surfaces on a pin-on-disk tribometer. The honing pattern of an engine cylinder bore was simulated on the disks. These disks have similar average surface heights with either plateaued or non-plateaued surface finish. Friction, wear and scuffing resistance of plateaued and non-plateaued disks were evaluated. Results from the pin-on-disk tribometer show that in the hydrodynamic lubrication regime plateaued and non-plateaued disks have the same friction, while in the mixed lubrication regime the plateaued surface has less friction. The author's findings also reveal that plateaued surfaces tend to have higher wear resistance but lower scuffing resistance. It also confirms the conventional wisdom that plateaued surf...
Lack of specific (3H) prazosin binding sites in dog and rabbit cerebral arteries

Abstract In order to explore the characteristics of alpha adrenergic receptors on cerebrovascular smooth muscle, specific binding sites for the alpha 1 adrenergic ligand, ( 3 H) prazosin, were studied in blood vessel homogenates. No specific ( 3 H) prazosin binding was found in either rabbit or dog cerebral arteries, but specific binding was demonstrated in the rabbit saphenous and ear arteries. In the ear artery 3 H-prazosin binding was saturable with a K d of 0.51 ± 0.20 nM and a Bmax of 89 ± 29 fmoles/mg protein. To confirm the adequacy of our membrane preparation, homogenates of both dog and rabbit cerebral arteries showed saturable specific binding with two different ligands: one for muscarinic receptors, [ 3 H](-) quinuclidinyl benzilate (QNB) and one for alpha 2 adrenergic receptors, ( 3 H) yohimbine. The results of these studies demonstrate a lack of alpha 1 adrenergic receptors on cerebral blood vessels, confirming functional studies showing only a weak contractile response to norepinephrine.
Role of airway recruitment and derecruitment in lung injury

The mechanical forces generated during the ventilation of patients with acute lung injury causes significant lung damage and inflammation. Low-volume ventilation protocols are commonly used to prevent stretch-related injury that occurs at high lung volumes. However, the cyclic closure and reopening of pulmonary airways at low lung volumes, i.e., derecruitment and recruitment, also causes significant lung damage and inflammation. In this review, we provide an overview of how biomedical engineering techniques are being used to elucidate the complex physiological and biomechanical mechanisms responsible for cellular injury during recruitment/derecruitment. We focus on the development of multiscale, multiphysics computational models of cell deformation and injury during airway reopening. These models, and the corresponding in vitro experiments, have been used to both elucidate the basic mechanisms responsible for recruitment/derecruitment injury and to develop alternative therapies that make the epithelium more resistant to injury. For example, models and experiments indicate that fluidization of the cytoskeleton is cytoprotective and that changes in cytoskeletal structure and cell mechanics can be used to mitigate the mechanotransduction of oscillatory pressure into inflammatory signaling. The continued application of biomedical engineering techniques to the problem of recruitment/derecruitment injury may therefore lead to novel and more effective therapies.
Laser surface-engineered vanadium carbide coating for extended die life

Abstract A successful effort has been made to deposit vanadium carbide on AISI H13 steel using Nd:YAG laser. In this study a continuous, adherent, crack-, and porosity-free coating has been obtained which can serve as a protective layer for various surfaces. The coating is composite in nature. To explore the properties of this coating in greater detail, it has been evaluated for chemical, structural, and mechanical properties. Another aspect of this work is to identify the suitability of this coating to protect die-casting die surfaces from the attack of molten aluminum. A number of different mechanisms, such as corrosive attack and erosion by molten aluminum and oxidation of the die surface, act to reduce the life of die-casting dies. In view of this, the coating has been tested for preliminary analysis such as high-temperature oxidation by conducting thermogravimetric analysis and for liquid metal corrosion resistance by immersion test in liquid aluminum. It shows excellent oxidation resistance below 600 °C and performs well in the immersion test in liquid aluminum by reducing the extent of attack of molten aluminum on the H13 steel.
Hopf Bifurcation in Viscous Incompressible Flow Down an Inclined Plane: a Numerical Approach

In this article we investigate numerically a Hopf bifurcation phenomenon for a viscous incompressible flow down an inclined plane. This problem has been discussed by Nishida et al. who proved the existence of periodic solutions bifurcating from the steady flow. Using a computational methodology based on finite elements for the space discretization and on operator splitting for the time discretization, we have been able to reproduce the results predicted by Nishida et al.
Technology acceptance model: A replicated test using TETRAD

The technology acceptance model proposes that ease of use and usefulness predict the acceptance of information technology. Since its inception, the model has been widely applied in understanding user acceptance behavior. In a recent study on e-commerce applications, we surprisingly found that the model was validated when tested in isolation but failed within the larger nomological network. In this paper, we applied TETRAD III to explore the issue. As expected, we discovered two spurious associations in the model and fundamentally challenge its validity and hundreds of related studies. © 2009 Wiley Periodicals, Inc.
Land use in Nigeria

Abstract Prior to the Land Use Decree of 1978, the Nigerian land tenure system had become the object of intense attack and defence by vested interests promoting their views on changes in the tenure system which would best increase food and fibre production. The many points of view could be classified into two opposing camps: those who regarded the tenure system as inimical to agricultural development with emphasis on food production; and, those who argued that the tenure system was not a hindrance at that time. This article provides background information on issues leading to the land tenure reform in Nigeria; points out some of the shortcomings of past direct government control and management of land, and the Land Use Decree; suggests needed modifications to the Land Use Decree's implementation; and, derives some food production policy implications.
Fibroblasts from long-lived bird species are resistant to multiple forms of stress

SUMMARY Evolutionary senescence theory postulates that aging results from the declining force of natural selection with increasing chronological age. A goal of comparative studies in the biology of aging is to identify genetic and biochemical mechanism(s) driving species-specific differences in the aging process that are the end product of life history trade-offs. We hypothesized that cells from long-lived bird species are more resistant to stress agents than are cells from short-lived species, and that cells from birds are more resistant to stress than are cells from relatively short-lived mammals of similar size. We tested primary fibroblast cultures from 35 species of free-living birds for their resistance to multiple forms of cellular stress and found that cell lines from longer-lived species were resistant to death caused by cadmium ( R 2 =0.27, P =0.002), paraquat ( R 2 =0.13, P =0.03), hydrogen peroxide ( R 2 =0.09, P =0.07) and methyl methanesulfonate ( R 2 =0.13, P =0.03), as well as to the metabolic inhibition seen in low-glucose medium ( R 2 =0.37, P
The SPEED cache coherence protocol for an optical multi-access interconnect architecture

The paper presents a low overhead, high performance cache coherence protocol designed to exploit high bandwidth point to point and broadcast features of optics. SPEED integrates the virtues of snoopy based schemes and directory based schemes into one efficient protocol. Directory assist is used exclusively for read traffic to eliminate unnecessary broadcasts while snoopy assist is used exclusively for write and synchronization traffic to reduce directory overhead and synchronization complexities. The proposed protocol has the potential to increase performance as a result of its global independence between read and write operations, concurrency in channel access, reduced contention, and efficient broadcast of coherence and synchronization events.
Need for emergency surgical airway reduced by a comprehensive difficult airway program

BACKGROUND:Inability to intubate and ventilate patients with respiratory failure is associated with significant morbidity and mortality. A patient is considered to have a difficult airway if an anesthesiologist or other health care provider experienced in airway management is unable to ventilate the
IN SEARCH OF YAX NUUN AYIIN I: Revisiting the Tikal Project's Burial 10

Recent epigraphic decipherments suggest that the child of a Teotihuacan ruler was installed as the ruler of Tikal in a.d. 379. This paper reviews the excavation and osteology of the tomb of this king, Yax Nuun Ayiin I. Estimating the age at death of the skeletons, I found that the skeletons surrounding the principal occupant include at least one adult, who was distinguished by a rare style of dental decoration. I report strontium isotope ratios obtained from the teeth of four of these skeletons. Comparison with a larger data set of strontium isotope ratios on Tikal burials indicates that none of the sampled skeletons from Burial PTP-010 were foreigners to the Maya Lowlands. Although native Tikal children cannot be distinguished from the skeletons of children who lived at nearby Peten sites using strontium isotopes, these results do not support epigraphic readings that identify Yax Nuun Ayiin as a child of Teotihuacan.
Effect of Rate of Blood Flow Through Large Blood Vessels on HIFU Temperature Rise

High Intensity Focused Ultrasound (HIFU) shows considerable promise as a minimally-invasive technique for tumor ablation. A typical HIFU procedure involves focusing of acoustic energy in a small region, with the absorbed acoustic energy causing localized rise in tissue temperature. Temperature rise of the order of 40–60°C is achieved within seconds, causing immediate cell necrosis in the targeted region.
Pairwise Algorithm for Distributed Transmit Beamforming

In this paper, we present a novel algorithm for distributed transmit beamforming enabling multiple single-antenna nodes to simultaneously transmit a common message such that they constructively interfere at the receiver. In order to constructively interfere, the nodes iteratively estimate and adjust their carrier phases with the help of receiver feedback. The receiver's feedback is based on composite channel estimates calculated from two simultaneous transmissions initiated by the nodes at each iteration. We prove that starting from arbitrary carrier phases, the algorithm converges to the maximum gain almost surely. The algorithm is compared to the 1-Bit Feedback algorithm presented in [3] through simulation, and is shown to outperform it by margins of 4:1 and 3:1 on metrics reflecting power consumption and convergence rate, respectively. We simulate the impact of phase estimation errors on the algorithm's steady-state gain and show it to be robust to moderately large errors of plusmn 20deg. We analyze the causes of asynchrony in simultaneous message transmissions and simulate its contribution to phase estimation errors in the context of IEEE 802.15.4 packets. We show that the contribution falls within the acceptable plusmn 20deg range.