bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting the Binding Affinity of Epitope‐Peptides with HLA‐A*0201 by Encoding Atom‐Pair Non‐covalent Interaction Information between Receptor and Ligands
Authors: Hu Lu , Ai Zhenglin , Liu Ping , Xiong Quan , Min Min , Lan Chunhui , Wang Jun , Fan Lilin , Chen Dongfeng
Published: May 2010

A structure‐based method was used to characterize the non‐covalent interactions of HLA‐A*0201 with its peptide ligands. In this procedure, protein and peptide atoms were classified into 16 types in terms of their chemical property and local environment, and a 16 × 16 matrix was then defined to describe the interaction mode of 256 atom‐pairs between the receptor and ligand in a complex structure. Three biologically related chemical forces as electrostatic, van der Waals, and hydrophobic potentials were separately calculated for each element of the matrix to yield 768 structural descriptors encoding the detailed information about the non‐covalent interactions involved in protein–peptide binding. We employed this method to perform quantitative structure–activity relationship (QSAR) study of a data panel consisting of 419 non‐apeptides with known binding affinities to HLA‐A*0201 protein. Several QSAR models were constructed using partial least square regression (PLS) coupled with or without genetic algorithm (GA)‐variable selection, and these models were validated rigorously and investigated systematically by using external test set and one‐way analysis of variance. Results show that diverse properties have significant contributions to the HLA‐A*0201–peptide binding. Particularly, the hydrophobicity and electrostatic property at the anchor residues of peptides confer a significant specificity and stability for the bound complexes.
Structure–Activity Relationships (SAR) Research of Thiourea Derivatives as Dual Inhibitors Targeting both HIV‐1 Capsid and Human Cyclophilin A
Authors: Chen Kan , Tan Zhiwu , He Meizi , Li Jiebo , Tang Shixing , Hewlett Indira , Yu Fei , Jin Yinxue , Yang Ming
Published: May 2010

HIV‐1 capsid (CA) and human cyclophilin A (CypA) play important roles in HIV‐1 assembly and disassembly processes, which are critical in HIV‐1 replication. Based on the discovery of thiourea derivatives targeting both of the two proteins and indicating effective inhibitory activities in our group, we designed and synthesized a new class of thiourea derivatives. Their abilities to bind to capsid and cyclophilin A were determined by ultraviolet spectroscopic analysis, fluorescence binding affinity, and PPIase inhibition assay. Furthermore, the newly synthesized compounds were tested for their antiviral activities and cytotoxicities using CEM cells. According to the biological evaluation and subsequent molecular docking analyses, we studied the structure–activity relationships of thiourea derivatives. Three optimal compounds (K17, K24, K25) based on the achieved structure–activity relationships would be the basis for future optimization.
Inhibition of Mycobacterial Growth by Plumbagin Derivatives
Authors: Mathew Ritta , Kruthiventi Anil K. , Prasad Jalli V. , Kumar Sadula P. , Srinu Garlapati , Chatterji Dipankar
Published: May 2010

Electron transport and respiratory pathways are active in both latent and rapidly growing mycobacteria and remain conserved in all mycobacterial species. In mycobacteria, menaquinone is the sole electron carrier responsible for electron transport. Menaquinone biosynthesis pathway is found to be essential for the growth of mycobacteria. Structural analogs of the substrate or product of this pathway are found to be inhibitory for the growth of Mycobacterium smegmatis and M. tuberculosis. Several plumbagin [5‐hydroxy‐2‐methyl‐1, 4‐naphthaquinone] derivatives have been analyzed for their inhibitory effects of which butyrate plumbagin was found to be most effective on M. smegmatis mc2155, whereas crotonate plumbagin showed greater activity on M. tuberculosis H37Rv. Effect on electron transport and respiration was demonstrated by butyrate plumbagin inhibiting oxygen consumption in M. smegmatis. Structural modifications of these molecules can further be improved upon to generate new molecules against mycobacteria.
Discourse Markers across Speakers and Settings
Authors: Fox Tree Jean E.
Published: May 2010

Viewing discourse markers as one of a class of signals that communicators use to manage conversation can help make sense of the varied and contradictory functions ascribed to them. Issues for further testing include demonstrating that speakers and listeners ascribe particular functions to particular markers, tracking the development of these functions as children age, tracking how these functions are adopted by second language learners, and documenting how discourse marker use changes across technological settings.
Does Economic Growth Cause Environmental Recovery? Geographical Explanations of Forest Regrowth
Authors: Mansfield Becky , Munroe Darla K. , McSweeney Kendra
Published: May 2010

This study examines the links between economic change and environmental recovery. We first review the influential framework known as Forest Transition Theory (FTT), which uses the experience of the North to posit a causal linkage between economic growth and forest regrowth. We then lay out problems with this theory and offer an alternative. Our central argument is that FTT provides faulty explanations of forest regrowth because it treats economic development as a characteristic of places. Drawing from geographical scholarship that sees economic development as occurring through dynamic relationships among places, we contend instead that forest regrowth in the North is due not to a universal process of economic development, but rather reflects the ability of wealthy regions to import forest and agricultural products, thereby exporting environmental impact. Economic growth, therefore, cannot be prescribed as a universal catalyst for environmental recovery because any such recovery relies on degradation elsewhere. Future research on forest regrowth should investigate multiple environment–economy relationships that both create and depend on differences among places.
The Academic Geography Video Genre: A Methodological Examination
Authors: Bauch Nicholas
Published: May 2010

This article compliments the video “Across Space: Finding the farm in the city.” It first outlines key methodological considerations in the production of a video in the academic geography video genre, including technology, scripting, editing, and the implications of authorship related to each of these. Then it discusses the intellectual aims of the video, which are to (i) show where the farm is represented in the city, (ii) show that by using the categories of urban and rural it allows us to attach values to places of a certain character, sometimes unjustifiably so, and (iii) demonstrate the transformative properties of space, i.e., how the meanings of artifacts change when they are used in different spatial contexts. The article concludes with methodological suggestions for other videographers wishing to produce motion pictures that relate themes frequently undertaken in academic geography.
From the Background to the Spotlight: TASK Channels in Pathological Conditions
Authors: Bittner Stefan , Budde Thomas , Wiendl Heinz , Meuth Sven G.
Published: May 2010

TWIK‐related acid‐sensitive potassium channels (TASK1–3) belong to the family of two‐pore domain (K2P) potassium channels. Emerging knowledge about an involvement of TASK channels in cancer development, inflammation, ischemia and epilepsy puts the spotlight on a leading role of TASK channels under these conditions. TASK3 has been especially linked to cancer development. The pro‐oncogenic potential of TASK3 could be shown in cell lines and in various tumor entities. Pathophysiological hallmarks in solid tumors (e.g. low pH and oxygen deprivation) regulate TASK3 channels. These conditions can also be found in (autoimmune) inflammation. Inhibition of TASK1,2,3 leads to a reduction of T cell effector function. It could be demonstrated that TASK1−/−mice are protected from experimental autoimmune inflammation while the same animals display increased infarct volumes after cerebral ischemia. Furthermore, TASK channels have both an anti‐epileptic as well as a pro‐epileptic potential. The relative contribution of these opposing influences depends on their cell type‐specific expression and the conditions of the cellular environment. This indicates that TASK channels are per se neither protective nor detrimental but their functional impact depends on the “pathophysiological” scenario. Based on these findings TASK channels have evolved from “mere background” channels to key modulators in pathophysiological conditions.
On Model Selection Curves
Authors: Müller Samuel , Welsh Alan H.
Published: May 2010

Many popular methods of model selection involve minimizing a penalized function of the data (such as the maximized log‐likelihood or the residual sum of squares) over a set of models. The penalty in the criterion function is controlled by a penalty multiplier λ which determines the properties of the procedure. In this paper, we first review model selection criteria of the simple form “Loss + Penalty” and then propose studying such model selection criteria as functions of the penalty multiplier. This approach can be interpreted as exploring the stability of model selection criteria through what we call model selection curves. It leads to new insights into model selection and new proposals on how to select models. We use the bootstrap to enhance the basic model selection curve and develop convenient numerical and graphical summaries of the results. The methodology is illustrated on two data sets and supported by a small simulation. We show that the new methodology can outperform methods such as AIC and BIC which correspond to single points on a model selection curve.
Metabolic Abnormalities in Adult and Geriatric Major Depression With and Without Comorbid Dementia
Authors: Blank Karen , Szarek Bonnie L. , Goethe John W.
Published: May 2010

J Clin Hypertens (Greenwich). 2010;12:456–461. ©2010 Wiley Periodicals, Inc.

Metabolic abnormalities and metabolic syndrome (MetS) increasingly have been linked to depression. The authors studied examined inpatients 35 years and older with major depressive disorder (MDD) to determine the prevalence of component metabolic abnormalities and the full MetS with age, treatment, and comorbid dementia. Data analysis involved retrospective cross‐sectional review from a nonprofit psychiatry inpatient service of all discharges 35 years and older with a diagnosis of MDD during a 3 year period (April 1, 2003 to March 31, 2006) (N=1718). Metabolic measures included waist circumference, lipid measurements, glucose, and hypertension diagnosis. Abnormal metabolic measures and MetS were highly prevalent in both young and old patients with MDD: one or more component was present in 87.6% of older (65–99 years old) and 79.9% of younger patients. Full MetS was present in 31.5% of older and 28.9% of younger patients (not significant, P=0.85). Metabolic abnormalities were not associated with atypical antipsychotics after controlling other variables. One‐quarter (n=79, 24.9%) of older inpatients had a dementia co‐diagnosis. Older patients with MDD and dementia had greater risk of elevated glucose while younger patients were more often hypertensive. Longitudinal studies are needed to determine the relationships of MDD with or without dementia with these highly prevalent abnormal metabolic measures and MetS.
Why Physicians Do Not Prescribe a Thiazide Diuretic
Authors: Sutton Emily , Wilson Holly , Kaboli Peter J. , Carter Barry L.
Published: May 2010

J ClinHypertens (Greenwich). 2010;12:502–507. © 2010 Wiley Periodicals, Inc.

The purpose of this study was to evaluate the reasons physicians provided when the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines recommending a thiazide diuretic as a first line treatment for hypertension were not followed. A subsample of patients from a randomized controlled study who had uncontrolled blood pressure at an index visit and were not prescribed a thiazide were evaluated. Differences in groups that received any medication change or therapeutic lifestyle changes counseling and those that did not were compared. Differences in treatment were also compared for patients who received educational materials with or without telephone calls and financial incentive with a control group. The authors examined whether patients achieved blood pressure control in 12 months. The results show providers are not aggressive enough with getting blood pressure to goal and patients who are more educated about hypertension may be less likely to experience clinical inertia.
Attitudes and Practices of Resident Physicians Regarding Hypertension in the Inpatient Setting
Authors: Neal Axon Robert , Garrell Robin , Pfahl Kyle , Fisher Julie E. , Zhao Yumin , Egan Brent , Weder Alan
Published: May 2010

J Clin Hypertens (Greenwich). 2010;12:698–705. ©2010 Wiley Periodicals, Inc.

Hypertension is prevalent in the population at large and among hospitalized patients. Little has been reported regarding the attitudes and patterns of care of physicians managing nonemergent elevated blood pressure (BP) among inpatients. Resident physicians in internal medicine (IM), family medicine (FM), and surgery were surveyed regarding inpatient BP management. One hundred eighty‐one questionnaires were completed across 3 sites. Respondents generally considered inpatient BP control a high priority. A majority of IM and FM residents indicated following the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) consensus guidelines for inpatients compared to 20% of surgery residents (P<.001). While trainees did not appear to strictly follow JNC 7 guidelines for goal BP of 140/90 mm Hg, they did report making frequent BP medication changes (∼51% reported changing regimens for >50% of hypertensive patients). Overall ∼90% indicated that discharging a hypertensive patient on a drug regimen established during hospitalization is preferable to reverting to the regimen in place at the time of admission. Resident physicians regard elevated BP inpatient management as important, but attitudes and practice vary between specialties. JNC 7 guidelines may not be appropriate for inpatient use. Future research should focus on developing functional diagnostic criteria for hypertension in the inpatient setting and determining best practices inpatient BP management.
Public Dying: Death in the Media and Jade Goody
Authors: Woodthorpe Kate
Published: May 2010

Abundant in books, on television, in film, on the internet, and in newspapers and magazines, in the twenty‐first century death is hugely accessible. Within recent years, sociologists have responded to this visibility by examining death in the media, including its role and status in popular culture and ‘public mourning’, seen for example following the death of Diana, Princess of Wales in 1997. This article considers a third strand of death in the media that requires sociological attention: public dying. Drawing on the extensive media coverage of reality TV personality Jade Goody’s dying and subsequent death in early 2009, the article examines the way in which Goody’s dying illustrated how it can be commodified.
Stimulation of human and mouse erythrocyte Na+–K+–2Cl− cotransport by osmotic shrinkage does not involve AMP‐activated protein kinase, but is associated with STE20/SPS1‐related proline/alanine‐rich kinase activation
Authors: Sid Brice , Miranda Lisa , Vertommen Didier , Viollet Benoît , Rider Mark H.
Published: May 2010

This study was undertaken to investigate whether the mechanism of increased Na+–K+–2Cl− (NKCC1) cotransporter activity by osmotic shrinkage involved AMP‐activated protein kinase (AMPK) activation. AMPK was found to phosphorylate a recombinant GST‐dogfish (1–260) NKCC1 fragment at Ser38 and Ser214, corresponding to Ser77 and Ser242 in human NKCC1, respectively. Incubation of human erythrocytes with 20 μm A769662 AMPK activator increased Ser242 NKCC1 phosphorylation but did not stimulate 86Rb+ uptake. Under hypertonic conditions in human red blood cells (RBCs) incubated with 0.3 m sucrose, NKCC1 activity increased as measured by bumetanide‐sensitive 86Rb+ uptake and AMPK was activated. However, there was no effect of AMPKα1 deletion in mouse RBCs on the increased rate of 86Rb+ uptake induced by hyperosmolarity. AMPK activation by osmotic shrinkage of mouse RBCs was abrogated by 10 μm STO‐609 CaMKKβ inhibitor, but incubation with STO‐609 did not affect the increase in 86Rb+ uptake induced by hyperosmolarity. Osmotic shrinkage of human and mouse RBCs led to activation loop phosphorylation of the STE20/SPS1‐related proline/alanine‐rich kinase (SPAK) at Thr233, which was accompanied by phosphorylation of NKCC1 at Thr203/207/212, one of which (Thr207) is responsible for cotransporter activation. Therefore, phosphorylation‐induced activation of NKCC1 by osmotic shrinkage does not involve AMPK and is likely to be due to SPAK activation.
Acid‐sensing ion channels in rat hypothalamic vasopressin neurons of the supraoptic nucleus
Authors: Ohbuchi Toyoaki , Sato Kaori , Suzuki Hideaki , Okada Yasunobu , Dayanithi Govindan , Murphy David , Ueta Yoichi
Published: May 2010

Body fluid balance requires the release of arginine vasopressin (AVP) from the neurohypophysis. The hypothalamic supraoptic nucleus (SON) is a major site of AVP synthesis, and AVP release is controlled somatodendritically or at the level of nerve terminals by electrical activities of magnocellular neurosecretory cells (MNCs). Acid‐sensing ion channels (ASICs) are neuronal voltage‐insensitive cationic channels that are activated by extracellular acidification. Although ASICs are widely expressed in the central nervous system, functional ASICs have not been assessed in AVP neurons. ASICs are modulated by lactate (La−), which reduces the extracellular calcium ion concentration. We hypothesize that ASICs modify neuronal function through La− that is generated during local hypoxia resulting from osmotic stimulation in the SON. In the present study, we used the whole‐cell patch‐clamp technique to show that acid‐induced ASIC current is enhanced by La− in isolated rat SON MNCs that express an AVP‐enhanced green fluorescent protein (eGFP) transgene. Immunohistochemistry and multi‐cell reverse transcriptase‐polymerase chain reaction experiments revealed that these neurons express the ASIC1a and ASIC2a subunits. In addition, increased La− production was specifically observed in the SON after osmotic stress. These results suggest that interaction between ASICs and La− in the SON plays an important role in the regulatory mechanism of body fluid homeostasis.
Modulation of somatosensory‐evoked cortical blood flow changes by GABAergic inhibition of the nucleus basalis of Meynert in urethane‐anaesthetized rats
Authors: Piché Mathieu , Uchida Sae , Hara Sanae , Aikawa Yoshihiro , Hotta Harumi
Published: May 2010

Vascular changes associated with brain functions are thought to be tightly coupled with neuronal activity through neuronal glucose consumption or the local release of vasoactive agents. In contrast, another view suggests that cortical blood flow is strongly regulated by the nucleus basalis of Meynert (NBM), independently of regional metabolism. Thus, although cortical regional cerebral blood flow (rCBF) variations induced by somatosensory stimulation are strongly linked to neuronal activity, they may also be partly controlled by the NBM. In the present study, cortical rCBF alterations in response to innocuous brushing of the hindlimb (HL) were investigated by laser speckle contrast imaging. The contribution of NBM to these changes was examined after injection of the GABAergic agonist muscimol into the right NBM, allowing comparison of somatosensory‐evoked cortical rCBF modifications before and after NBM inactivation. As expected, HL brushing elicited a robust rCBF increase in the contralateral parietal cortex (PC), over the representation of the HL. However, these alterations were decreased, by approximately 40%, in the hemisphere ipsilateral to muscimol inactivation of NBM, whereas vehicle injection did not produce any significant variation. The results demonstrate that cortical rCBF changes induced by somatosensory stimulation are partly regulated by NBM.
Mechanisms of synchronous activity in cerebellar Purkinje cells
Authors: Wise Andrew K. , Cerminara Nadia L. , Marple‐Horvat Dilwyn E. , Apps Richard
Published: May 2010

Complex spike synchrony is thought to be a key feature of how inferior olive climbing fibre afferents make their vital contribution to cerebellar function. However, little is known about whether the other major cerebellar input, the mossy fibres (which generate simple spikes within Purkinje cells, PCs), exhibit a similar synchrony in impulse timing. We have used a multi‐microelectrode system to record simultaneously from two or more PCs in the posterior lobe of the ketamine/xylazine‐anaesthetized rat to examine the relationship between complex spike and simple spike synchrony in PC pairs located mainly in the A2 and C1 zones in crus II and the paramedian lobule. PC pairs displaying correlations in the occurrence of their complex spikes (coupled PCs) were usually located in the same zone and were also more likely to exhibit correlations in the timing of their spontaneous simple spikes and associated pauses in activity. In coupled PCs, synchrony in both complex spike and simple spike activity was enhanced and the relative timing in the occurrence of complex spikes could be altered by peripheral stimulation. We conclude that the functional coupling between PC pairs in their complex spike and simple spike activity can be significantly modified by sensory inputs, and that mechanisms besides electrotonic coupling are involved in generating PC synchrony. Synchronous activity in multiple PCs converging onto the same cerebellar nuclear cells is likely to have a significant impact on cerebellar output that could form important timing signals to orchestrate coordinated movements.
Survey of Aging for LRB of a Base-Isolated Building Completed 15 Years Ago
Authors: Shimoda Ikuo , Masayoshi Ikenaga , Mochimaru Masami , Miyazaki Mitsuru , Sakuraba Shinichi , Masuda Koichi , Wake Tomotaka
Published: May 2010

We researched aging of the LRB (Lead Rubber Bearing) installed in a base-isolated building which was constructed 15 years ago. The hardness of the cover rubber and the height were measured for 35 LRBs which were installed in the building. The compression test and combined compression shear test with monitor samples and actually installed LRB were performed to search changes in their hysteresis characteristics. The monitor samples were composed of 4 LRBs and 1 RB. Main results obtained were as follows: 1) The LRBs installed in the TC building crept approximately 1 (mm) during 15 years and did not changed during last 5 years. 2) The hardness of the cover rubber did not change against that of 15 years ago. 3) From the testing of the monitor samples, the compression stiffness increased approximately 17% and the shear stiffness increased approximately 5%, however the yield force changed quite a little during 15 years on average. As a result, the suitability of the design specifications of the LRB was confirmed.
Elevators Compatible to Intermediate-Floors Base Seismic Isolation Building
Authors: Miyata Koichi , Sekiya Yuji , Shigeta Masayuki
Published: May 2010

This paper describes a new elevator system applied for Intermediate-Floors Base Seismic Isolation Buildings, to replace the existing system with the ultimate aim to reduce the installation and construction costs. Features of the new elevator system such as high tensioned steel guide rail, new entrance structure, new type of guide rail reinforcements called rail backing and new control systems are introduced in the paper. Details of a new design method to determine the stiffness and the length of the rail backing is also listed.
Study on Three-Dimensional Seismic Isolation System for Next Generation Nuclear Power Plant: Independent Cable Reinforced Rolling-Seal Air Spring
Authors: Kageyama Mitsuru , Hino Yoshihiko , Moro Satoshi
Published: May 2010

In Japan, the development of the next generation NPP has been conducted in recent years. In the equipment/piping design of the plant, seismic condition has been required much more mitigate than before. So, the three-dimensional (abbreviation to 3D) seismic isolation system development has also been conducted since 2000. The superlative 3D base isolation system for the entire building was proposed. The system is composed of cable reinforced air springs, rocking arresters and viscous dampers. Dimensions of the air spring applied to the actual power plant are 8 meters in the outer-diameter and 3.5 meters in height. The allowable half strokes are 1.0 meters in horizontal and 0.5 meters in vertical respectively. The maximum supporting weight for a single device is 70 MN. The inner design air pressure is about 1.8MPa. This air spring has a distinguishing feature, which realizes 3D base isolation with a single device, whose natural periods are about 4 seconds in horizontal and about 3 seconds in vertical. In order to verify the 3D performance of this system, several feasibility tests were conducted. Firstly, 3D shaking table tests were conducted. The test specimen is scaled 1/4 of the actual device. The outer diameter and inner air pressure of air spring is 2 meters and 0.164 MPa. Next, a pressure resistant test for the sub cable, textile sheet and rubber sheet, which composed air spring, were conducted as a full scale model test. Then, air permeation test for the rubber sheet was also conducted. As a result, the proposed system was verified that it could be applied to the actual nuclear power plants.
Fundamental Study of Active Mass Damper for Improving Livability of Houses Against Traffic Vibration
Authors: Matsumoto Yukito , Hasegawa Osamu , Shimoda Ikuo , Seto Kazuto
Published: May 2010

In Japan, there are many houses built on limited space and also besides side of causeways and railroads, due to population concentration in the cities in recent years. Houses with 3-stories or slender structure houses are susceptible to traffic vibration induced by external forces. This affect frequency creates an uncomfortable environment for habitation. Because houses often have a complex geometry, it is difficult to establish the vibration characteristics of a structure. Furthermore, the response characteristics of a house will change with environmental condition. To address some of these issues, an Active Mass Damper (AMD) has developed in order to supply for users with a reasonable price. This AMD has a mass of 176kg in weight supported by guide springs, and driven by an AC servomotor and a wire rope. The AMD is controlled by two methods, LQ Control and Direct Displacement Feedback (DDFB) Control. In this report, a control effect is examined through simulation when the AMD is installed in the RF level of a 3-story house model. The simulation results are demonstrated that the AMD could improve the uncomfortable environment in houses. A matter of particular note was reduction of about 4 dB in the overall vibration level. Concerning an experimental study about this equipment, refer to the following report, “Fundamental experiment of Active Mass Damper for houses against traffic vibration”.
Whirl Vibration Control of Winder by Using Simply Supported Dynamic Absorber
Authors: Iba Daisuke , Tsutsui Shinsuke , Sone Akira , Masuda Arata
Published: May 2010

This paper proposes a dynamic absorber effective in machines and structures, which can be modeled as a flexible beam with a circular section. A winder, which is textile machineries as an example, is taken up, and vibration control of a spindle with a circular section is performed. The winder has a cantilever type hollow spindle which is supported at one end and free at the other, and there is a vibration problem that is caused by increase of vibration amplitude of the spindle at critical speed. In the case of the winder, because of winding up a synthetic fiber to the spindle, there is no space to mount dynamic absorbers to the outside of the spindle. Then new dynamic absorber is developed for mounting to the inside of the free end of the hollow spindle. The dynamic absorber is simply composed of a mass, a rod, and two spherical surface bearings, and it is possible to suppress whirl vibration of the spindle. The effectiveness of the proposed dynamic absorber is confirmed by the simplified and the practical experiment.
Vibration Control Performance of Damping Coupled Tuned Mass Dampers
Authors: Masaki Nobuo , Hirata Hisashi
Published: May 2010

Recently tuned mass dampers have been installed on three-story prefabricated houses for reducing of traffic-induced vibration and improving living comfort. This tuned mass damper consists of a mass unit, spring units and laminated rubber bearings. The mass is supported by four laminated rubber bearings, and spring units are used for adjusting the natural frequency of the tuned mass damper to the optimal value. Vibration control performance of this type of tuned mass dampers is deteriorated when the natural frequency of the house is changed. To solve this problem, the authors have developed a damping coupled tuned mass damper. In this type of tuned mass damper, two mass units having slightly different natural frequencies are coupled by using a damping unit. In this paper, mechanism and vibration control performance of the damping coupled tuned mass damper are described.
High Performance Passive Damper With Ingenious Hydraulic Valve System
Authors: Matsunaga Yoshinori , Tagami Jun , Kurino Haruhiko , Yamada Toshikazu
Published: May 2010

Newly developed ingenious hydraulic valve system (MAIKO-Ben) autonomously controls the flow valve opening between two hydraulic chambers utilizing the pressure balance between them without an external power source. This impressive function can create a passive hydraulic damper with high performance equivalent to that of previously developed semi-active damper that can absorb much more structural vibration energy than a conventional passive damper. This damper works a semi-active damper while remaining passive. First, we explain the self-regulating hydraulic mechanism of this valve system. The flow control valve is activated through the hydraulic power accumulated in rather small buffer placed between the two hydraulic chambers, and produces maximum or minimum damping coefficient based on the pressure balance between them. Second, we present the results of dynamic loading tests conducted on a full-scale prototype damper (maximum force: 2MN) under both sinusoidal waves and non-stationary seismic response waves. It is confirmed that the developed device showed excellent energy dissipation capacity as expected, and also that the damper’s dynamic characteristics could be well simulated through simply modeling the above hydraulic mechanism. According to these results, it is verified that the MAIKO-Ben system has enough promise to be applied to the real buildings.
A Proposed Method for Anticipated-Allowable Piping, Mechanical and Seismic Nozzle Load Design
Authors: Botsis Ch. , Anagnostides G. , Kokavesis N.
Published: May 2010

Nozzle loads impose an important constraint in the design of pressure containing equipment. Pressure vessels are connected to external piping by a nozzle welded to the vessel wall and a flange connection. The nozzle loads are due to the piping expansion or contraction caused by the difference between the installation and operating temperatures. Pressure vessel designers need to know, early in the design process, the piping loads that a nozzle may be subjected to. It is important that such loads do not overstress the vessel-nozzle intersection. However the actual piping loads many times are only determined long after the pressure vessel materials are ordered and even procured. The intention of this paper is to provide an empirical but also realistic load set as a function of nozzle external radius, r, vessel external radius, R, vessel thickness, t, and allowable stress, S. The basis of this work is practical experience and also existing theoretical work. This will be a valuable tool in the hands of the pressure vessel mechanical designer. It will allow him to prescribe an early-heuristic estimate of the allowable nozzle loads that will cover external piping loads. These “anticipated” or design loads will allow a pressure vessel mechanical designer to reinforce his design early into the manufacturing of a pressure vessel. Finally, piping engineers will know the terminal allowable loads and thus determine the best piping routing and support arrangements if space constraints allow it.
Dynamic Characteristics of Structure With Bolted Joint Considering Some Factors
Authors: Aoki Shigeru
Published: May 2010

Bolted joints are widely used for pressure vessels and piping system. Many studies on strength and stiffness of bolted joint are carried out. However, few studies on the dynamic characteristics of structure with bolted joint are carried out. The dynamic characteristics are important for design of structure subjected to earthquake excitations. In this paper, the effect of bolted joints on dynamic characteristics of structure is examined. First, the damping ratio and the natural frequency of specimens with some types of bolted joints are measured. Those are obtained for some factors, amplitude of excitation, applied torque. Obtained results are compared with those for the specimen without bolted joint. It is found that the damping ratio increases and the natural frequency becomes lower. Next, modeling of the bolted joint is presented. The bolted joint is modeled using additional mass, stiffness and damping elements. Finally, using model of bolted joint, response of the structure with bolted joint subjected to earthquake excitation is examined. Earthquake excitation is modeled as stationary random excitation. Mean square values of the response are obtained. Standard deviation of the acceleration response of the structure with bolted joint are lower than those without bolted joint.
Reduction of First Excursion Probability Due to Plastic Deformation and Absorbed Energy
Authors: Aoki Shigeru
Published: May 2010

When the system is subjected to excess seismic loading, spring element has hysteresis loop characteristic caused by plastic deformation. Energy is dissipated by hysteresis loop characteristic. Elastic-plastic damper which utilizes energy absorption is practically used. On the other hand, response is nonstationary random process because seismic loading is nonstationary random process. In such a case, reliability of the system should be evaluated in probabilistic manner. Some failure modes are observed. First excursion failure is one of the most important failure modes. First excursion probability, that is, probability of occurrence of first excursion failure, also represents the characteristic of random process. In this paper, the first excursion probability and absorbed energy by hysteresis loop characteristic are obtained from theoretical method. This method is based on equivalent linearization method. Bilinear hysteresis loop characteristic is used as force-deformation relation. It is concluded that the first excursion probability decreases with the increase of absorbed energy.
Study on Nonlinear Vibration Characteristic Evaluation of Nonlinear Vibration System With Gaps by Transition Probability Density Function
Authors: Shintani Masanori , Ikuta Hiroyuki , Takada Hajime
Published: May 2010

In this paper, the transition probability density functions between response velocity and response displacement in nonlinear vibration systems which have the restoring force characteristic of a cubic equation are governed by the Fokker-Planck Equation. The experimental probability density functions are compared with analytical results. The analytical model of the cubic equation as Duffing Equation is proposed by the restoring force characteristic of the nonlinear vibration system with gaps in the experiments. However, a slight difference for the frequency range of the transfer function was shown by simulation results. Then, it is considered using transition probability density functions in the response characteristic. For stationary random input waves, the probability density function between the response displacement and the response velocity are easily estimated by the Fokker-Planck Equation and the Duffing Equation. The slight difference of the transfer function of the response acceleration is evaluated by the scattering of the restoring force characteristic estimated by the probability density function and self-natural frequency curve. The R.M.S. value and the transfer function of the experimental results are compared with the analytical results. It is thought that the estimation of the probability density function of the response has validity. It is thought that the evaluation of the nonlinear vibration characteristics by the probability density function is valid.
Seismic Proving Test of Ultimate Piping Strength: Design Method Confirmation Test
Authors: Suzuki Kenichi , Abe H. , Suzuki Kohei
Published: May 2010

The proving test of a large-scale piping system with a piping bore of 200A (8B) and made from carbon steel material was conducted to assure the safety margin of the current and new design codes for piping. Two test models were used, one for the design method confirmation test and one for the ultimate strength test. The design confirmation test model reflected the structural features and vibration characteristics of piping systems. For the ultimate strength test, the piping system was modified by adding one more mass and removing one horizontal support. The original seismic wave to the input seismic wave was selected to be the “S2” seismic wave for a PWR building. The time-pitch and the excitation level were then modified to meet the test conditions. For the design confirmation test, a series of tests was initiated at a level of the current allowable primary stress limit (3Sm) for the “S2” seismic wave (off-resonance), culminating in an elasto-plastic response test up to 4.5 times the allowable primary stress limit (on-resonance as an extreme case) with no evidence of piping failure. Pre-test and post-test analyses were performed. The post-test analysis results, which considered some differences of actual input acceleration and damping ratio, compare well with the design confirmation test results of elasto-plastic global response and local strain.
Experimental Study on Shaking Table Control Using Adaptive Control
Authors: Shinohara Yuichiro , Shimizu Nobuyuki , Sato Eiji
Published: May 2010

The full-scale earthquake testing facility (large-scale shaking table), which is now being constructed by the Japanese government, requires stable and precise control for conducting satisfactory dynamical fracturing tests of structure model. We had ended the experimental study of enhancing control by using a small-scale shaking table, and then started the experimental study of enhancing control by using a medium-scale shaking table. A final goal of the series of the study is to obtain a guideline of enhancing control for the experiment by using the large-scale shaking table. In this paper, the Minimal Control Synthesis (MCS) is applied to a shaking table-test control. The MCS has been implemented in the controller design for the experiments of the small-scale and the medium-scale shaking table and proved to be effective for enhancing shaking table control by the experiments. This paper reports the results of the control experiments.
Computation of Input Energy to Test Structure on Shaking Table Test
Authors: Fuyama Hiroyuki , Yasuda Chiaki , Kajii Shinichiro , Sakuno Makoto
Published: May 2010

In case of destruction test on shaking table, the energy, dissipated in the process of collapse, could be employed as one of indexes to grasp the test structure strength. In general, for the vibration systems, internal dissipated energies are equal to externally supplied energies. Considering the shaking table and test structure as one vibration system, the input energy generated by actuators of shaking table can be used to estimate the dissipated energy during collapse of the test structure. This paper describes followings. (1) Derive computation method of dissipated energy based on information of shaking table system. (2) Show validity of computation method Results of numerical simulation employing shaking table simulator.
Analysis and Experiment on the Effect of Seismic Protection of Buildings by High Damping Rubber Bearings
Authors: Pu Jun-Ping , Tsai C. S. , Huang Jian-Fa , Chen Bo-Jen , Fang Yao-Min
Published: May 2010

In recent years, many studies on base isolation strategies and devices have been developed and applied in U. S. A., Europe, Japan, and New Zealand. The high damping rubber bearing belongs to one kind of the earthquake-proof ideas of base isolation technologies. The installation of high damping rubber bearings can lengthen the natural period of a building and simultaneously reduce the earthquake-induced energy trying to impart to the building. The objective of this paper is to investigate the base isolation effect of high damping rubber bearings. The uniaxial, biaxial, and triaxial shaking table tests were performed to study the seismic behavior of a 0.4-scale three-story isolated steel structure in the National Center for Research on Earthquake Engineering in Taiwan. The experimental and analytical results show that the nonlinear mechanical characteristics of the high damping rubber bearings can be reasonably simulated.
Passive Control of Seismic Response of Piping Systems
Authors: Parulekar Y. M. , Reddy G. R. , Vaze K. K. , Muthumani K.
Published: May 2010

Passive energy dissipating devices like Elasto-plastic dampers (EPDs) can be used for eliminating snubbers and reducing the response of piping systems subjected to seismic loads. Cantilever and 3-dimensional piping systems were tested with and without EPD on shake table. Using a finite element model of the piping systems, linear and nonlinear time history analysis is carried out using Newmark’s time integration technique. Equivalent linearization technique such as Caughey method is used to evaluate the equivalent damping of the piping systems supported on Elasto-Plastic damper. An iterative response spectrum method is used for evaluating response of the piping system using this equivalent damping. The analytical maximum response displacement obtained at the Elasto-Plastic damper support for the two piping systems is compared with experimental values and time history analysis values. It has been concluded that, iterative response spectrum technique using Caughey equivalent damping is simple and results in reasonably acceptable response of the piping systems supported on EPD.
Room temperature capacitance-voltage profile and photoluminescence for delta doped InGaAs single quantum well
Authors: Ban K.-Y. , Dahal S. N. , Honsberg C. B. , Nataraj L. , Bremner S. P. , Cloutier S. G.
Published: May 2010

Room temperature capacitance-voltage (C-V) profile and photoluminescence (PL) studies of δ-doped single InGaAs quantum well samples are reported. The purpose was to obtain the confined carrier occupancy in the conduction band offset and observe any relevant phenomena. The results show that the peak intensity of the C-V profiles was almost linearly proportional to sheet carrier concentration and the full width at half maximum of the C-V profiles became narrower with increasing doping level in the barrier layer. This is interpreted as being due to improved confinement of electrons as a result of band bending induced by the δ-doping layer. This explanation was further supported by PL data that show the transition corresponding to the dominant peak changed with different δ-doping levels and that all of the transitions were redshifted. Finally, theoretical calculations of the band structure based on a four band k⋅p method are presented to explain the observed results.
Optical characterization of AlxGa1−xAs/GaAs modulation-doped heterostructures grown under As2 and As4 fluxes
Authors: Vázquez-Cortés D. , Soubervielle-Montalvo C. , Méndez-García V. H. , Zamora-Peredo L. , Jiménez-Sandoval S.
Published: May 2010

The authors have investigated the optical properties of AlxGa1−xAs/GaAs modulation-doped heterostructures grown under different experimental conditions, mainly by changing the molecular species of the As beam stemming from a cracker cell at different temperatures. By low-temperature photoluminescence (PL) spectroscopy, they observed that using As2 instead of As4, the crystal quality of the ternary alloy improves significantly since narrower lines in the near-band-gap energy of AlGaAs were obtained when the temperature of the As-cracker zone increased. The experimental position of the energy of the ternary band gap transition as a function of temperature fits the Varshni and Viña functional forms satisfactorily, while it is difficult to assess the data for those samples grown employing As4. It was found that the As2 molecular beam reduces the creation of donor acceptor levels in AlGaAs, as compared with As4. The PL spectra line shape in the GaAs band gap region shows lines associated with band-to-band transition, exciton-bound to neutral-point defects (d,X), and conduction-band to neutral carbon-acceptor (C,A0). The intensity of these transitions was found to be independent of the As molecular-beam species; nevertheless, the photoreflectance spectra of the samples show line shape changes close to the GaAs band gap energy. This region has been related to the electron mobility of two-dimensional electron-gas systems.
Temperature dependent lattice constant of Al0.90Ga0.10AsySb1−y
Authors: Breivik Magnus , Nilsen Tron Arne , Myrvågnes Geir , Selvig Espen , Fimland Bjørn-Ove
Published: May 2010

Using x-ray diffraction, the in-plane and out-of-plane lattice constants of Al0.90Ga0.10AsySb1−y epilayers grown on GaSb and GaAs substrates were determined between 30 and 398 °C for y=0.003–0.059. The bulk lattice constant was then calculated from the in-plane and out-of-plane lattice constants. A polynomial function for the bulk lattice constant as a function of y and temperature was derived from a fit to the resulting data. Comparison to measured out-of-plane lattice constants of platinum-coated Al0.90Ga0.10AsySb1−y indicates that the polynomial function is valid up to around 550 °C. The polynomial function can be used to determine the lattice matching of Al0.90Ga0.10AsySb1−y to, e.g., GaSb at typical growth temperatures used for growth of cladding layers in laser structures. A formula is given for calculating the As mole fraction for lattice matching to GaSb at a given temperature.
Parallel fabrication of monolithic nanoscopic tunnel junctions for molecular devices
Authors: Gupta R. , Willis B. G.
Published: May 2010

Nanoelectrode tunneling devices for molecular level measurements have been grown using atomic layer deposition. These devices are two-terminal nanostructures separated by a free space region on the order of one to several nanometers where molecules can adsorb and be probed with electrical measurements including electron tunneling spectroscopy. Successful fabrication of parallel devices arranged in arrays is achieved by exploiting a nanofeedback mechanism that aids in the convergence of independent devices to tunneling. Independent devices are shown to behave similarly for thermal expansion, adsorption, desorption, and tunneling spectroscopy measurements. Adsorption is shown to be strongly influenced by the large electric fields in the nanoscopic tunnel junctions, and a model based on electric field forces qualitatively captures these effects. Desorption events are observed as stochastic processes for the independent devices and parallel inelastic electron tunneling spectroscopy measurements show features that are similar between independent devices. These data demonstrate parallel operation of nanoelectrode devices and suggest that it may be possible to scale the devices to have many nanojunctions operating in parallel.