bluuebunny/crossref_metadata_2025 huggingface dataset:
Promoting early presentation of breast cancer: development of a psycho-educational intervention
Authors: Burgess C.C. , Bish A.M. , Hunter H.S. , Salkovskis P. , Michell M. , Whelehan P. , Ramirez A.J.
Published: March 2008

Objectives: Women who delay presenting with breast cancer have a reduced chance of survival. Older women, who are at greater risk of developing breast cancer, are more likely to delay presenting with the disease. The aim of this developmental work was to design a psycho-educational intervention to promote early help-seeking by older women with breast cancer symptoms. We also aimed to demonstrate the feasibility of implementing the intervention with women attending for their final invited mammogram in the National Health Service (NHS) Breast Screening Programme.

Methods: The intervention was designed to address the factors associated with delayed presentation by women with breast cancer. These risk factors were placed in a theoretical framework to understand patient delay. The intervention incorporated behavioural change techniques that, according to previous research, have been demonstrated to be effective.

Results: The intervention was developed in two formats to be delivered by diagnostic radiographers: a booklet alone and a brief interview plus the booklet. The intervention was acceptable to both older women and healthcare professionals in the NHS Breast Screening Programme.

Discussion: The intervention will be tested ultimately in a multicentre randomized controlled trial to determine whether it can reduce the proportion of older women who delay their presentation and thereby save lives.
Clustering of cognate proteins among distinct proteomes derived from multiple links to a single seed sequence
Authors: Barbosa-Silva Adriano , Satagopam Venkata P , Schneider Reinhard , Ortega J Miguel
Published: March 2008

Background

Modern proteomes evolved by modification of pre-existing ones. It is extremely important to comparative biology that related proteins be identified as members of the same cognate group, since a characterized putative homolog could be used to find clues about the function of uncharacterized proteins from the same group. Typically, databases of related proteins focus on those from completely-sequenced genomes. Unfortunately, relatively few organisms have had their genomes fully sequenced; accordingly, many proteins are ignored by the currently available databases of cognate proteins, despite the high amount of important genes that are functionally described only for these incomplete proteomes.

Results

We have developed a method to cluster cognate proteins from multiple organisms beginning with only one sequence, through connectivity saturation with that Seed sequence. We show that the generated clusters are in agreement with some other approaches based on full genome comparison.

Conclusion

The method produced results that are as reliable as those produced by conventional clustering approaches. Generating clusters based only on individual proteins of interest is less time consuming than generating clusters for whole proteomes.
Toward an operative diagnosis in sepsis: a latent class approach
Authors: De La Rosa Gisela D , Valencia Marta L , Arango Clara M , Gomez Carlos I , Garcia Alex , Ospina Sigifredo , Osorno Susana , Henao Adriana , Jaimes Fabián A
Published: March 2008

Background

Recent data have suggested that 18 million of new sepsis cases occur each year worldwide, with a mortality rate of almost 30%. There is not consensus on the clinical definition of sepsis and, because of lack of training or simply unawareness, clinicians often miss or delay this diagnosis. This is especially worrying; since there is strong evidence supporting that early treatment is associated with greater clinical success. There are some difficulties for sepsis diagnosis such as the lack of an appropriate gold standard to identify this clinical condition. This situation has hampered the assessment of the accuracy of clinical signs and biomarkers to diagnose sepsis.

Methods/design

Cross-sectional study to determine the operative characteristics of three biological markers of inflammation and coagulation (D-dimer, C-reactive protein and Procalcitonin) as diagnostic tests for sepsis, in patients admitted to hospital care with a presumptive infection as main diagnosis.

Discussion

There are alternative techniques that have been used to assess the accuracy of tests without gold standards, and they have been widely used in clinical disciplines such as psychiatry, even though they have not been tested in sepsis diagnosis. Considering the main importance of diagnosis as early as possible, we propose a latent class analysis to evaluate the accuracy of three biomarkers to diagnose sepsis.
Influence of two different resection techniques (conventional liver resection versus anterior approach) of liver metastases from colorectal cancer on hematogenous tumor cell dissemination – prospective randomized multicenter trial
Authors: Schmidt T , Koch M , Antolovic D , Reissfelder C , Schmitz-Winnenthal FH , Rahbari NN , Schmidt J , Seiler CM , Büchler MW , Weitz J
Published: March 2008

Background

Surgical hepatic resection remains the treatment of choice for patients with liver metastases from colorectal cancer despite the use of alternative therapeutic strategies. Although this procedure provides long-term survival in a significant number of patients, 50–75% of the patients develop intra- and/or extrahepatic recurrence. One possible reason for tumor recurrence may be intraoperative hematogenous tumor cell dissemination due to mechanical manipulation of the tumor during hepatic resection. Surgical technique may have an influence on hematogenous tumor cell spread. We hypothesize that hematogenous tumor cell dissemination may be reduced by using the anterior approach technique compared to conventional liver resection.

Methods/Design

This is a multi-centre prospective randomized controlled, superiority trial to compare two liver resection techniques of liver metastases from colorectal cancer. 150 patients will be included and randomized intraoperatively after surgical exploration just prior to resection. The primary objective is to compare the anterior approach with the conventional liver resection technique with regard to intraoperative haematogenous tumor cell dissemination. As secondary objectives we examine five year survival rates (OS and DFS), blood loss, duration of operation, requirement of blood transfusions, morbidity rate, prognostic relevance of tumor cell detection in blood and bone marrow and the comparison of tumor cell detection by different detection methods.

Conclusion

This trial will answer the question whether there is an advantage for the anterior approach technique compared to the conventional resection group with regard to tumor cell dissemination. It will also add further information about prognostic differences, safety, advantages and disadvantages of each technique.

Trial registration

Current controlled trials – ISRCTN45066244
A mathematical model of venous neointimal hyperplasia formation
Authors: Budu-Grajdeanu Paula , Schugart Richard C , Friedman Avner , Valentine Christopher , Agarwal Anil K , Rovin Brad H
Published: March 2008

Background

In hemodialysis patients, the most common cause of vascular access failure is neointimal hyperplasia of vascular smooth muscle cells at the venous anastomosis of arteriovenous fistulas and grafts. The release of growth factors due to surgical injury, oxidative stress and turbulent flow has been suggested as a possible mechanism for neointimal hyperplasia.

Results

In this work, we construct a mathematical model which analyzes the role that growth factors might play in the stenosis at the venous anastomosis. The model consists of a system of partial differential equations describing the influence of oxidative stress and turbulent flow on growth factors, the interaction among growth factors, smooth muscle cells, and extracellular matrix, and the subsequent effect on the stenosis at the venous anastomosis, which, in turn, affects the level of oxidative stress and degree of turbulent flow. Computer simulations suggest that our model can be used to predict access stenosis as a function of the initial concentration of the growth factors inside the intimal-luminal space.

Conclusion

The proposed model describes the formation of venous neointimal hyperplasia, based on pathogenic mechanisms. The results suggest that interventions aimed at specific growth factors may be successful in prolonging the life of the vascular access, while reducing the costs of vascular access maintenance. The model may also provide indication of when invasive access surveillance to repair stenosis should be undertaken.
CD 56 staining in liver biopsies does not help in differentiating extrahepatic biliary atresia from other causes of neonatal cholestasis
Authors: Mahjoub Fatemeh E , Khairkhah Reza Hadizadeh , Sani Mehri Najafi , Irvanloo Guiti , Monajemzadeh Maryam
Published: March 2008

Introduction

Several conditions are considered in differential diagnosis of neonatal cholestasis. Of these the most important is extrahepatic biliary atresia (EHBA), while prompt diagnosis and surgical correction of obstruction can ameliorate clinical symptoms, provides long term survival for about one fourth of patients and serves as an important bridge to transplantation for many others. From histopathologic standpoint, features of EHBA overlaps with other diagnoses and so ancillary tests such as immunohistochemical staining for CD56 is suggested by some authors as a helpful tool in differential diagnosis.

Hereby we wanted to examine this staining in our center which is a referral children hospital and to prove its efficacy in our problematic cases.

Materials and Methods

By retrospective review of pathology records during 2000 to 2006 in Markaze Tebbi Koodakan (children hospital related to Tehran University of Medical Sciences), we selected 17 cases of EHBA as patients and 12 cases with other diagnoses as controls, both with some degree of bile ductular proliferation in liver biopsies. EHBA cases were all proved by surgery. Four of control cases also underwent surgery but proved to have open ducts by intra-operative cholangiography. Long term follow up and other tests ruled out EHBA in other 8 cases. Hematoxylin-Eosin stains of paraffin blocks were studied again and freshly prepared sections were immunostained for CD56.

Results

Bile ducts and proliferating bile ductules were strongly positive for CD56 in 6 of 17 cases of EHBA. In 7 out of 17, positivity were seen in more than two thirds of portal tracts. In controls, one case showed strong positivity and 6 out of twelve showed positivity in more than two thirds of portal tracts. The intensity and distribution of CD56 staining did not differ significantly between two groups.

Discussion

Despite findings of previous studies, we have shown that CD56 staining can not help as an ancillary test in differential diagnosis of neonatal cholestasis and perhaps other markers should be tested in this regard.
Concomitant sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman Disease) and diffuse large B-cell lymphoma: a case report
Authors: Moore James C , Zhao Xiaohui , Nelson Edward L
Published: March 2008

Introduction

Sinus histiocytosis with massive lymphadenopathy, also known as Rosai-Dorfman Disease, is a rare and benign source of lymphadenopathy first described in 1969, which mimics neoplastic processes. This disease commonly presents in children and young adults with supra-diaphragmatic lymphadenopathy or extranodal lesions consisting of tissue infiltrates composed of a polyclonal population of histiocytes. Since its description greater than 400 cases have been described, sometimes in patients with a variety of treated and untreated neoplastic diseases. However, the literature contains reports of only 19 cases of Rosai-Dorfman Disease in association with lymphomas, Hodgkin's or non-Hodgkin's. The majority of these cases have the two diagnoses, malignant lymphoma and Rosai-Dorfman Disease, separated in time. Interestingly, infradiaphragmatic lymphadenopathy was a feature in the majority of previously reported cases of Rosai-Dorfman Disease and non-Hodgkin's lymphoma.

Case presentation

This report provides details of a case with co-existing sinus histiocytosis with massive lymphadenopathy and diffuse large B cell non-Hodgkin's lymphoma. This case is the fifth described case of simultaneous Rosai-Dorfman Disease and concurrent non-Hodgkin's lymphoma. Unfortunately, the diagnosis of a clinically aggressive diffuse large B cell lymphoma was made at autopsy. The aggressive biological behavior of the diffuse large B cell lymphoma in this patient may have been related to the underlying immune dysregulation believed to be part of the pathophysiology of Rosai-Dorfman Disease.

Conclusion

Taken together this report and the preceding reports of Rosai-Dorfman Disease and non-Hodgkin's lymphoma suggests that in cases with a diagnosis of Rosai-Dorfman Disease in the setting of prominent infradiaphragmatic lymphadenopathy, clinicians should maintain a high index of suspicion for the presence of occult non-Hodgkin's lymphoma especially if the clinical course is atypical for classic Rosai-Dorfman Disease.
Cross-kingdom patterns of alternative splicing and splice recognition
Authors: McGuire Abigail M , Pearson Matthew D , Neafsey Daniel E , Galagan James E
Published: March 2008

Background

Variations in transcript splicing can reveal how eukaryotes recognize intronic splice sites. Retained introns (RIs) commonly appear when the intron definition (ID) mechanism of splice site recognition inconsistently identifies intron-exon boundaries, and cassette exons (CEs) are often caused by variable recognition of splice junctions by the exon definition (ED) mechanism. We have performed a comprehensive survey of alternative splicing across 42 eukaryotes to gain insight into how spliceosomal introns are recognized.

Results

All eukaryotes we studied exhibit RIs, which appear more frequently than previously thought. CEs are also present in all kingdoms and most of the organisms in our analysis. We observe that the ratio of CEs to RIs varies substantially among kingdoms, while the ratio of competing 3' acceptor and competing 5' donor sites remains nearly constant. In addition, we find the ratio of CEs to RIs in each organism correlates with the length of its introns. In all 14 fungi we examined, as well as in most of the 9 protists, RIs far outnumber CEs. This differs from the trend seen in 13 multicellular animals, where CEs occur much more frequently than RIs. The six plants we analyzed exhibit intermediate proportions of CEs and RIs.

Conclusion

Our results suggest that most extant eukaryotes are capable of recognizing splice sites via both ID and ED, although ED is most common in multicellular animals and ID predominates in fungi and most protists.
Connective Tissue Growth Factor and Susceptibility to Renal and Vascular Disease Risk in Type 1 Diabetes
Authors: Jaffa Ayad A. , Usinger William R. , McHenry M. Brent , Jaffa Miran A. , Lipstiz Stuart R. , Lackland Daniel , Lopes-Virella Maria , Luttrell Louis M. , Wilson Peter W. F.
Published: March 2008

Objective: We explored the relevance and significance of connective tissue growth factor (CTGF) as a determinant of renal and vascular complications among type 1 diabetic patients.

Methods and Results: We measured the circulating and urinary levels of CTGF and CTGF N fragment in 1050 subjects with type 1 diabetes from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study cohort. We found that hypertensive diabetic subjects have significantly higher levels of plasma log CTGF N fragment relative to normotensive subjects (P = 0.0005). Multiple regression analysis showed a positive and independent association between CTGF N fragment levels and log albumin excretion rate (P < 0.0001). In categorical analysis, patients with macroalbuminuria had higher levels of CTGF N fragment than diabetic subjects with or without microalbuminuria (P < 0.0001). Univariate and multiple regression analyses demonstrated an independent and significant association of log CTGF N fragment with the common and internal carotid intima-media thickness. The relative risk for increased carotid intima-media thickness was higher in patients with concomitantly elevated plasma CTGF N fragment and macroalbuminuria relative to patients with normal plasma CTGF N fragment and normal albuminuria (relative risk = 4.76; 95% confidence interval, 2.21–10.25; P < 0.0001).

Conclusion: These findings demonstrate that plasma CTGF is a risk marker of diabetic renal and vascular disease.
Cadherin switching
Authors: Wheelock Margaret J. , Shintani Yasushi , Maeda Masato , Fukumoto Yuri , Johnson Keith R.
Published: March 2008

The cadherin molecules at adherens junctions have multiple isoforms. Cadherin isoform switching (cadherin switching) occurs during normal developmental processes to allow cell types to segregate from one another. Tumor cells often recapitulate this activity and the result is an aggressive tumor cell that gains the ability to leave the site of the tumor and metastasize. At present, we understand some of the mechanisms that promote cadherin switching and some of the pathways downstream of this process that influence cell behavior. Specific cadherin family members influence growth-factor-receptor signaling and Rho GTPases to promote cell motility and invasion. In addition, p120-catenin probably plays multiple roles in cadherin switching, regulating Rho GTPases and stabilizing cadherins.
Microneme protein 8 – a new essential invasion factor inToxoplasma gondii
Authors: Kessler Henning , Herm-Götz Angelika , Hegge Stephan , Rauch Manuel , Soldati-Favre Dominique , Frischknecht Friedrich , Meissner Markus
Published: March 2008

Apicomplexan parasites rely on sequential secretion of specialised secretory organelles for the invasion of the host cell. First, micronemes release their content upon contact with the host cell. Second, rhoptries are discharged, leading to the formation of a tight interaction (moving junction) with the host cell, through which the parasite invades. The functional characterisation of several micronemal proteins in Toxoplasma gondii suggests the occurrence of a stepwise process. Here, we show that the micronemal protein MIC8 of T. gondii is essential for the parasite to invade the host cell. When MIC8 is not present, a block in invasion is caused by the incapability of the parasite to form a moving junction with the host cell. We furthermore demonstrate that the cytosolic domain is crucial for the function of MIC8 and can not be functionally complemented by any other micronemal protein characterised so far, suggesting that MIC8 represents a novel, functionally distinct invasion factor in this apicomplexan parasite.
Beyond Wnt inhibition: new functions of secreted Frizzled-related proteins in development and disease
Authors: Bovolenta Paola , Esteve Pilar , Ruiz Jose Maria , Cisneros Elsa , Lopez-Rios Javier
Published: March 2008

The secreted Frizzled-related proteins (SFRPs) are a family of soluble proteins that are structurally related to Frizzled (Fz) proteins, the serpentine receptors that mediate the extensively used cell-cell communication pathway involving Wnt signalling. Because of their homology with the Wnt-binding domain on the Fz receptors, SFRPs were immediately characterised as antagonists that bind to Wnt proteins to prevent signal activation. Since these initial studies, interest in the family of SFRPs has grown progressively, offering new perspectives on their function and mechanism of action in both development and disease. These studies indicate that SFRPs are not merely Wnt-binding proteins, but can also antagonise one another's activity, bind to Fz receptors and influence axon guidance, interfere with BMP signalling by acting as proteinase inhibitors, and interact with other receptors or matrix molecules. Furthermore, their expression is altered in different types of cancers, bone pathologies, retinal degeneration and hypophosphatemic diseases, indicating that their activity is fundamental for tissue homeostasis. Here we review some of the debated aspects of SFRP-Wnt interactions and discuss the new and emerging roles of SFRPs.
Tribological behaviour of A390/Grp metal—matrix composites fabricated using a combination of rheocasting and squeeze casting techniques
Authors: Mahmoud T S
Published: March 2008

The dry sliding wear performance of hypereutectic A390 Al—Si alloy reinforced with graphite particulates (Grp) was investigated. Composites containing 4 and 8 wt% of Grp were produced by rheocasting technique followed by squeeze casting. Pins of the materials were rubbed against a 316 stainless steel disc using pin-on-ring type apparatus under various loads and speeds. It has been observed that both wear rate and the coefficient of friction of the composites decreased considerably with Grp additions. The A390/Grp composites exhibited higher wear resistance than those obtained for the monolithic A390 alloy. The formation of the hard tribo-layer on the surface of the composites assisted in increasing the wear resistance of these materials. It is believed that the reduction of the friction coefficient is attributed the presence of the graphite layers within the tribo-layer.
New design methodology for piezoelectric shunt structures using admittance analysis
Authors: Choi S-B , Kim H S , Park J-S
Published: March 2008

In this paper, a new design method for a piezoelectric shunt circuit to reduce unwanted vibration of flexible structures is proposed. Admittance is introduced to represent electromechanical characteristics of piezoelectric structures and to predict the performance of piezoelectric shunt system. It is shown that admittance of the piezoelectric structure is proportional to the dissipated energy in the shunt circuit. Admittance is used as a design index to construct the piezoelectric shunt system and obtained by finite-element method. The location, area, shape, and material property of piezoelectric patches are determined by admittance analysis. Vibration reduction of the piezoelectric structure with shunt circuit is realized by experiments. It is proved from damped system response of the piezoelectric structure in frequency and time domains that the admittance is proportional to the performance of the piezoelectric shunt system. A flow chart for design procedures using admittance analysis is presented to save design cost of the piezoelectric shunt system.
Vibration measurement of a cantilever beam using root embedded piezoceramic sensor
Authors: Sunar M , Al-Bedoor B O
Published: March 2008

Numerical and experimental studies are carried out to investigate the usability of a piezoceramic (PZT) sensor placed in the root of a stationary cantilever beam for measuring structural vibrations. The ability of the sensor for picking up the vibration signals during both the transient and steady-state phases is investigated. The piezoelectric equations obtained using the Hamilton's principle together with the finite-element approximation are utilized to extract the voltage outputs of the PZT sensor. An experimental set-up, to validate the theoretical results, is designed and manufactured. The experimentally measured sensor voltages are compared with the numerical ones. The results showed the excellent performance of the sensors in reading vibration signals of the beam. The root embedded PZT approach is an important step towards the application of measuring rotating blade vibrations.
Noise identification in reverberant sound field by using simulated annealing
Authors: Chiu M-C
Published: March 2008

Noise control is important and essential in an enclosed machine room where the noise level is restricted by the occupational safety and health act. Before the appropriate noise abatement is performed, the identification work of location and free-field sound energy of equipment inside the reverberant sound field become crucial and an absolute prerequisite. Research on new techniques of single noise control and sound absorption system has been well addressed and developed; however, the research work on sound identification for an existing multi-noise enclosed room is rare and observably insufficient. Without the actual location and pure free-field noise level, noise control work will be improper and wasted; therefore, the numerical approach of noise recognition from the reverberant sound field becomes necessary and obligatory.

In this paper, the novel technique of simulated annealing (SA) in conjunction with the method of minimized variation square is applied in the following numerical optimization. In addition, various sound monitoring systems in detecting the noise condition within the echo area is also introduced. Before noise identification can be carried out, the accuracy of the mathematical model in a single-noise enclosed system has to be checked by SoundPlan (a professional simulation package in sound field). Thereafter, the SA recognition of three kinds of multi-noise systems has to be exemplified and fully explored. The results reveal that either the locations or sound power levels (SWLs) of noises can be precisely distinguished. Consequently, this paper may provide an efficient and rapid way in distinguishing the location and free-field noise level of equipment in a complicated sound field.
Fuzzy model-based condition monitoring of a dry vacuum pump via time and frequency analysis of the exhaust pressure signal
Authors: Twiddle J A , Jones N B , Spurgeon S K
Published: March 2008

A fuzzy model-based diagnostic scheme is designed to monitor dry vacuum pump performance and detect two fault conditions, mechanical inefficiency and exhaust system blockage. The diagnostic scheme is based on time and frequency analysis of the exhaust pressure signal. Power ratios of certain frequency components in the signal spectrum can be used to predict the gas load, motor current and hence mechanical efficiency. Changes in the periodic features of the signal, symptomatic of fault conditions can be detected using a fuzzy reference model. A fuzzy rule base is used to analyse outputs of the reference model and the load estimator and produce a diagnosis of the pump condition. Experimental results show that the motor current estimation had a root mean squared error of 0.11 A (∼5 per cent). Two fault symptoms, a 29 per cent obstruction of the exhaust silencer and an 8 per cent increase in current with respect to gas load, were simulated on the pump test bed and successfully diagnosed.
Effect of three-dimensional deformation on the limit load of highly weld strength undermatched specimens under tension
Authors: Alexandrov S , Kocak M
Published: March 2008

In the case of welded structures with cracks, a number of parameters, such as those with units of length, makes it difficult to present the results of numerical solutions in a form convenient for direct engineering applications, such as flaw assessment procedures. For centre-cracked components under tension, it is shown in the current article that an effect of crack length on the limit load can be taken into account by means of an upper bound limit load for the corresponding structure with no crack without any additional numerical treatment. Using this result, it is sufficient to find an upper bound limit load for the structure with no crack and then to apply the analytical formulae for finding the corresponding limit load for the structure of interest.

Welding of some aluminium alloys for structural applications usually leads to a significantly lower strength (undermatched) weld joint. The approach proposed is used to demonstrate an effect of three-dimensional deformation on an upper bound limit load for such highly strength undermatched centre-cracked welded specimens under tension. This result can also be used in metal-forming applications where upper bound solutions are more useful than lower bound solutions.
A non-linear model for impinging jets atomization
Authors: Ibrahim E A , Outland B E
Published: March 2008

The problem considered is predicting the characteristics of the spray produced by atomization of an attenuating liquid sheet formed by the impingement of two liquid jets of equal diameters and momenta. A second-order non-linear perturbation analysis is employed to model the evolution of harmonic instability waves that lead to sheet distortion and fragmentation. The onset of atomization occurs when the uneven surface modulations of the thinning sheet bring its upper and lower interfaces in contact. It is found that the sheet is torn into ligaments at each half wavelength. The instability of the ligaments causes their eventual disintegration into drops. The results indicate that sheet breakup length, time, and resultant drop size decrease as Weber number is increased. A higher Weber number induces a greater sheet breakup thickness. The breakup length, thickness, time, and drop size are diminished at larger impingement angles. The theoretical predictions of the present non-linear model are in good agreement with available experimental data and empirical correlations for sheet breakup length and drop size.
The use of structured relationship modelling techniques as a tool to elicit customizable product features
Authors: Barrass D F , Roberts J , Jones R , Hague R , Dickens P
Published: March 2008

The current article discusses a procedure for the elicitation of product requirements from a target group of users. The use of the method to help develop products with customizable elements is evaluated as this is one area in which this procedure is considered effective. The technique of forming a structured relationship model uses open-ended questions to elicit subject's sensations when using the product under investigation. Inductive content analysis is then performed on the responses to allow a structured relationship model to be developed.
Observations during mechanical testing of Nitinol
Authors: Eaton-Evans J , Dulieu-Barton J M , Little E G , Brown I A
Published: March 2008

Superelastic and shape memory capabilities of Nitinol are strongly dependent on the alloy composition, its heat treatment, and mechanical deformation history. The current article presents a review of the behaviour of Nitinol and describes a characterization study conducted to determine the mechanical properties of the material, both by means of differential scanning calorimetry (DSC) and by mechanical testing at a range of temperatures. Values for key transformation temperatures are found using both techniques. It is concluded that mechanical deformation during sample preparation for DSC measurements may have led to material property modifications and hence erroneous phase transformation temperature values. It is shown that mechanical testing can provide a means of benchmarking DSC data.
Temperature and cavitation
Authors: Huang D G , Zhuang Y Q
Published: March 2008

Pressure, density, and temperature are the fundamental thermodynamic parameters. In a liquid flow field, once the local pressure drops to the saturated pressure, the liquid vapourizes and local cavitation occurs. The cavitation region of the flow is characterized by a mixture of liquid and vapour. Vapourization is an endothermic process. However, in the literature of the past several decades, this vapourization induced thermal effect was sometimes ignored in cavitating flows, and the temperature was always assumed as a constant in the whole flow field. In order to gain a deep insight into the mechanism of cavitation, temperature effects of cavitation are hereby investigated in this paper. An appreciable temperature drop has been found when cavitation occurs, which suggests that thermal effects in cavitating flows from the view of thermodynamics may be of great value to understand the mechanism of cavitation.
Polymer Incarcerated Gold Catalyzed Aerobic Oxidation of Hydroquinones and Their Derivatives
Authors: Miyamura Hiroyuki , Shiramizu Mika , Matsubara Ryosuke , Kobayashi Shu
Published: March 2008

Polymer-incarcerated gold (PI Au) cluster catalysts mediated aerobic oxidation of hydroquinones and catechols to quinones very efficiently under mild conditions. The characteristic role of water in the reaction system was also observed.
Uniform One-hole Particles Used as Versatile Micro-encapsulation
Authors: Bi Cai Xia , Wei Wei , Yang Jian , Gong Fang Ling , Su Zhi Guo , Ma Guang Hui
Published: March 2008

An interesting process for preparation of micro-encapsulation was investigated. In this process, the uniformly sized particles with controllable holes in their surface were obtained firstly. After loading the functional materials with small size, the holes were closed by the means of swelling with a selected solvent.
Facile Templating Methods to Remarkable Architectures of Nanoporous Carbon Spheres
Authors: Yamada Yuri , Nakamura Tadashi , Yano Kazuhisa
Published: March 2008

A colloidal crystal fabricated from monodispersed mesoporous silica spheres (MMSS) has been employed as a sacrificial template to prepare nanoporous carbon architectures. The mesostructure of MMSS was well replicated, even when they were fabricated to the colloidal crystal, in the nanopores of the carbon spheres. By changing the filtration process slightly, the 3D-packed nanoporous carbon colloidal crystal and the novel “ball in cup” carbon hierarchical structure were successfully obtained.
Distribution and Expression of Soluble Epoxide Hydrolase in Human Brain
Authors: Sura Priyanka , Sura Radhakrishna , EnayetAllah Ahmed E. , Grant David F.
Published: March 2008

Epoxyeicosatrienoic acids (EETs) are cytochrome P450 metabolites of arachidonic acid, which function in the brain to regulate cerebral blood flow and protect against ischemic brain injury. EETs are converted by soluble epoxide hydrolase (sEH) to the corresponding inactive diol metabolites. Previous animal studies have indicated that sEH gene deletion or treatment with sEH inhibitors results in increased levels of EETs and protection against stroke-induced brain damage. To begin elucidating the underlying mechanism for these effects, we sought to determine the distribution, expression, and activity of sEH in human brain samples obtained from patients with no neurological changes/pathologies. Immunohistochemical analyses showed the distribution of sEH mainly in the neuronal cell bodies, oligodendrocytes, and scattered astrocytes. Surprisingly, in the choroid plexus, sEH was found to be highly expressed in ependymal cells. Vascular localization of sEH was evident in several regions, where it was highly expressed in the smooth muscles of the arterioles. Western blot analysis and enzyme assays confirmed the presence of sEH in the normal brain. Our results indicate differential localization of sEH in the human brain, thus suggestive of an essential role for this enzyme in the central nervous system. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.
Boundary integral equations for acoustical inverse sound-soft scattering
Authors: Ivanyshyn O. , Johansson B. T.
Published: March 2008

The shape of a plane acoustical sound-soft obstacle is detected from knowledge of the far field pattern for one time-harmonic incident field. Two methods based on solving a system of integral equations for the incoming wave and the far field pattern are investigated. Properties of the integral operators required in order to apply regularization, i.e. injectivity and denseness of the range, are proved.
Neurodegeneration and Motor Dysfunction in a Conditional Model of Parkinson's Disease
Authors: Nuber Silke , Petrasch-Parwez Elisabeth , Winner Beate , Winkler Jürgen , von Hörsten Stephan , Schmidt Thorsten , Boy Jana , Kuhn Melanie , Nguyen Huu P. , Teismann Peter , Schulz Jörg B. , Neumann Manuela , Pichler Bernd J. , Reischl Gerald , Holzmann Carsten , Schmitt Ina , Bornemann Antje , Kuhn Wilfried , Zimmermann Frank , Servadio Antonio , Riess Olaf
Published: March 2008

α-Synuclein (α-syn) has been implicated in the pathogenesis of many neurodegenerative disorders, including Parkinson's disease. These disorders are characterized by various neurological and psychiatric symptoms based on progressive neuropathological alterations. Whether the neurodegenerative process might be halted or even reversed is presently unknown. Therefore, conditional mouse models are powerful tools to analyze the relationship between transgene expression and progression of the disease. To explore whether α-syn solely originates and further incites these alterations, we generated conditional mouse models by using the tet-regulatable system. Mice expressing high levels of human wild-type α-syn in midbrain and forebrain regions developed nigral and hippocampal neuropathology, including reduced neurogenesis and neurodegeneration in absence of fibrillary inclusions, leading to cognitive impairment and progressive motor decline. Turning off transgene expression in symptomatic mice halted progression but did not reverse the symptoms. Thus, our data suggest that approaches targeting α-syn-induced pathological pathways might be of benefit rather in early disease stages. Furthermore, α-syn-associated cytotoxicity is independent of filamentous inclusion body formation in our conditional mouse model.
Subunit-Specific Trafficking of GABAAReceptors during Status Epilepticus
Authors: Goodkin Howard P. , Joshi Suchitra , Mtchedlishvili Zakaria , Brar Jasmit , Kapur Jaideep
Published: March 2008

It is proposed that a reduced surface expression of GABAAreceptors (GABARs) contributes to the pathogenesis of status epilepticus (SE), a condition characterized by prolonged seizures. This hypothesis was based on the finding that prolonged epileptiform bursting (repetitive bursts of prolonged depolarizations with superimposed action potentials) in cultures of dissociated hippocampal pyramidal neurons (dissociated cultures) results in the increased intracellular accumulation of GABARs. However, it is not known whether this rapid modification in the surface-expressed GABAR pool results from selective, subunit-dependent or nonselective, subunit-independent internalization of GABARs. In hippocampal slices obtained from animals undergoing prolonged SE (SE-treated slices), we found that the surface expression of the GABAR β2/3 and γ2 subunits was reduced, whereas that of the δ subunit was not. Complementary electrophysiological recordings from dentate granule cells in SE-treated slices demonstrated a reduction in GABAR-mediated synaptic inhibition, but not tonic inhibition. A reduction in the surface expression of the γ2 subunit, but not the δ subunit was also observed in dissociated cultures and organotypic hippocampal slice cultures when incubated in an elevated KCl external medium or an elevated KCl external medium supplemented with NMDA, respectively. Additional studies demonstrated that the reduction in the surface expression of the γ2 subunit was independent of direct ligand binding of the GABAR. These findings demonstrate that the regulation of surface-expressed GABAR pool during SE is subunit-specific and occurs independent of ligand binding. The differential modulation of the surface expression of GABARs during SE has potential implications for the treatment of this neurological emergency.
Functional Imaging, Spatial Reconstruction, and Biophysical Analysis of a Respiratory Motor Circuit IsolatedIn Vitro
Authors: Koizumi Hidehiko , Wilson Christopher G. , Wong Stephen , Yamanishi Tadashi , Koshiya Naohiro , Smith Jeffrey C.
Published: March 2008

We combined real-time calcium-based neural activity imaging with whole-cell patch-clamp recording techniques to map the spatial organization and analyze electrophysiological properties of respiratory neurons forming the circuit transmitting rhythmic drive from the pre-Bötzinger complex (pre-BötC) through premotoneurons to hypoglossal (XII) motoneurons. Inspiratory pre-BötC neurons, XII premotoneurons (preMNs), and XII motoneurons (MNs) were retrogradely labeled with Ca2+-sensitive dye in neonatal ratin vitrobrainstem slices. PreMN cell bodies were arrayed dorsomedially to pre-BötC neurons with little spatial overlap; axonal projections to MNs were ipsilateral. Inspiratory MNs were distributed in dorsal and ventral subnuclei of XII. Voltage-clamp recordings revealed that two currents, persistent sodium current (NaP) and K+-dominated leak current (Leak), primarily contribute to preMN/MN subthreshold current–voltage relationships. NaP or Leak conductance densities in preMNs and MNs were not significantly different. We quantified preMN and MN action potential time course and spike frequency–current (f–I) relationships and found no significant differences in repetitive spiking dynamics, steady-statef–Igains, and afterpolarizing potentials. Rhythmic synaptic drive current densities were similar in preMNs and MNs. Our results indicate that, despite topographic and morphological differences, preMNs and MNs have some common intrinsic membrane, synaptic integration, and spiking properties that we postulate ensure fidelity of inspiratory drive transmission and conversion of synaptic drive into (pre)motor output. There also appears to be a common architectonic organization for some respiratory drive transmission circuits whereby many preMNs are spatially segregated from pre-BötC rhythm-generating neurons, which we hypothesize may facilitate downstream integration of convergent inputs for premotor pattern formation.
Neurite Outgrowth andIn VivoSensory Innervation Mediated by a CaV2.2–Laminin β2 Stop Signal
Authors: Sann Sharon B. , Xu Lin , Nishimune Hiroshi , Sanes Joshua R. , Spitzer Nicholas C.
Published: March 2008

Axons and dendrites of developing neurons establish distributed innervation patterns enabling precise discrimination in sensory systems. We describe the role of the extracellular matrix molecule, laminin β2, interacting with the CaV2.2 calcium channel in establishing appropriate sensory innervation.In vivo, CaV2.2 is expressed on the growth cones ofXenopus laevissensory neurites and laminin β2 is expressed in the skin. Culturing neurons on a laminin β2 substrate inhibits neurite outgrowth in a specific and calcium-dependent manner. Blocking signaling between laminin β2 and CaV2.2 leads to increased numbers of sensory terminalsin vivo. These findings suggest that interactions between extracellular matrix molecules and calcium channels regulate connectivity in the developing nervous system.
Acetylcholinesterase Expression in Muscle Is Specifically Controlled by a Promoter-Selective Enhancesome in the First Intron
Authors: Camp Shelley , De Jaco Antonella , Zhang Limin , Marquez Michael , De La Torre Brian , Taylor Palmer
Published: March 2008

Mammalian acetylcholinesterase (AChE) gene expression is exquisitely regulated in target tissues and cells during differentiation. An intron located between the first and second exons governs a ∼100-fold increase in AChE expression during myoblast to myotube differentiation in C2C12 cells. Regulation is confined to 255 bp of evolutionarily conserved sequence containing functional transcription factor consensus motifs that indirectly interact with the endogenous promoter. To examine controlin vivo, this region was deleted by homologous recombination. The knock-out mouse is virtually devoid of AChE activity and its encoding mRNA in skeletal muscle, yet activities in brain and spinal cord innervating skeletal muscle are unaltered. The transcription factors MyoD and myocyte enhancer factor-2 appear to be responsible for muscle regulation. Selective control of AChE expression by this region is also found in hematopoietic lineages. Expression patterns in muscle and CNS neurons establish that virtually all AChE activity at the mammalian neuromuscular junction arises from skeletal muscle rather than from biosynthesis in the motoneuron cell body and axoplasmic transport.
Withdrawal from Cocaine Self-Administration Normalizes Deficits in Proliferation and Enhances Maturity of Adult-Generated Hippocampal Neurons
Authors: Noonan Michele A. , Choi Kwang H. , Self David W. , Eisch Amelia J.
Published: March 2008

Relapse, a major problem in the treatment of cocaine addiction, is proposed to result in part from neuroadaptations in the hippocampus. We examined how a mediator of hippocampal neuroplasticity, adult neurogenesis in the subgranular zone (SGZ), was regulated by cocaine self-administration (CSA), and whether these changes were reversed by 4 weeks of withdrawal (CSA-WD) versus continued cocaine self-administration (CSA-CONT). Rats self-administered intravenous cocaine or saline for 3 weeks and were killed 2 h (CSA) or 4 weeks (CSA-WD, CSA-CONT) after injection with the S-phase marker bromodeoxyuridine (BrdU). Cells in several stages of adult neurogenesis were quantified: proliferating cells labeled by BrdU (2 h) or Ki-67; immature neurons labeled by doublecortin; and adult-generated neurons labeled with BrdU (4 weeks) and the mature neuronal marker NeuN. CSA decreased proliferation in both the SGZ and the subventricular zone (SVZ), a source of adult-generated olfactory neurons, changes reversed by CSA-WD. Unexpectedly, CSA-WD and CSA-CONT resulted in more immature doublecortin-immunopositive (+) neurons in the posterior SGZ and a normal number of adult-generated BrdU+ neurons in the SGZ, suggesting an enduring impact of CSA regardless of whether cocaine intake was stopped or continued. However, only CSA-WD rats had more adult-generated neurons with punctate BrdU staining, an indicator of enhanced maturity. These data suggest a mechanism for the cognitive and olfactory deficits seen in cocaine addicts, and further suggest that adult-generated neurons should be considered for their potential role in cocaine addiction and hippocampal-mediated relapse after cocaine withdrawal.
Competitive and Noncompetitive Odorant Interactions in the Early Neural Coding of Odorant Mixtures
Authors: Rospars Jean-Pierre , Lansky Petr , Chaput Michel , Duchamp-Viret Patricia
Published: March 2008

Most olfactory receptor neurons (ORNs) express a single type of olfactory receptor that is differentially sensitive to a wide variety of odorant molecules. The diversity of possible odorant-receptor interactions raises challenging problems for the coding of complex mixtures of many odorants, which make up the vast majority of real world odors. Pure competition, the simplest kind of interaction, arises when two or more agonists can bind to the main receptor site, which triggers receptor activation, although only one can be bound at a time. Noncompetitive effects may result from various mechanisms, including agonist binding to another site, which modifies the receptor properties at the main binding site. Here, we investigated the electrophysiological responses of rat ORNsin vivoto odorant agonists and their binary mixtures and interpreted them in the framework of a quantitative model of competitive interaction between odorants. We found that this model accounts for all concentration-response curves obtained with single odorants and for about half of those obtained with binary mixtures. In the other half, the shifts of curves along the concentration axis and the changes of maximal responses with respect to model predictions, indicate that noncompetitive interactions occur and can modulate olfactory receptors. We conclude that, because of their high frequency, the noncompetitive interactions play a major role in the neural coding of natural odorant mixtures. This finding implies that the CNS activity caused by mixtures will not be easily analyzed into components, and that mixture responses will be difficult to generalize across concentration.