bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of different negative pressure values in the process of infected wounds treated by vacuum‐assisted closure: an experimental study
Authors: Zhou Min , Yu Aixi , Wu Gang , Xia Chengyan , Hu Xiang , Qi Baiwen
Published: May 2012

Vacuum‐assisted closure (VAC) device is widely used to treat infected wounds in clinical work. Although the effect of VAC with different negative pressure values is well established, whether different negative pressures could result in varying modulation of wound relative cytokines was not clear. We hypothesise that instead of the highest negative pressure value the suitable value for VAC is the one which is the most effective on regulating wound relative cytokines. Infected wounds created on pigs' back were used to investigate the effects of varying negative pressure values of VAC devices. Wounds were treated with VAC of different negative pressure values or moist gauze, which was set as control. The VAC foam, semiocclusive dresses and moist gauze were changed on days 3, 5, 7 and 9 after wounds were created. When changing dressings, tissues from wounds were harvested for bacteria count and histology examination including Masson's trichrome stain and immunohistochemistry for microvessels. Western blot was carried out to test the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Results showed that on days 3 and 5 the number of bacteria in wounds treated by VAC with 75, 150, 225 and 300 mmHg was significantly decreased compared with that in wounds treated by gauze and 0 mmHg pressure value. However, there was no difference in wounds treated with negative pressure values of 75 , 150, 225 and 300 mmHg at any time spot. Immunohistochemistry showed that more microvessels were generated in wounds treated by VAC using 75 and 150 mmHg negative pressure comparing with that using 225 and 300 mmHg on days 3 and 5. However this difference vanished on days 7 and 9. Morphological evaluation by Masson's trichrome staining showed increased collagen deposition in VAC of 75 and 150 mmHg compared with that in VAC of 225 and 300 mmHg. Western blot showed that the expression of VEGF and bFGF significantly increased when the wounds treated with 75 and 150 mmHg negative pressure values compared with the wounds treated with 225 and 300 mmHg on day 5. Treatment using VAC with different negative pressure values more than 75 mmHg has similar efficiency on reducing bacteria in the infected wound. VAC with negative pressure values of 75 and 150 mmHg promote wound healing more quickly than other pressure values. Moreover, comparing with vigorous negative pressure, relatively moderate pressures contribute to wound healing via accelerated granulation growth, increased angiogenic factor production and improved collagen fibre deposition. Further study of this model may show other molecular mechanisms.
General equilibrium theory and competitive trade models
Authors: Jones Ronald W.
Published: May 2012

A rough generalization is that by and large economists who have contributed to establishing the properties of general equilibrium models, such as existence and optimality, form a rather different group from those who deal with simplified versions of general equilibrium in asking about comparative static questions, that is, international trade theorists. Paul Samuelson was a towering exception, making important contributions for both sets. Following his lead, this paper attempts to use an important technique developed by Samuelson to discuss how the body of general equilibrium theorists can gain from the portfolio of special simple models dealt with in competitive trade theory.
The dynamic Heckscher–Ohlin model: A diagrammatic analysis
Authors: Bond Eric W. , Iwasa Kazumichi , Nishimura Kazuo
Published: May 2012

In this paper, we show that the main results of dynamic Heckscher–Ohlin models (with non‐homothetic preferences) can be derived from diagrams which represent the basic functions in static models such as the Rybczynski line, income expansion paths, and excess demand functions at steady states. Results include not only the existence and the multiplicity of steady states in autarky and under free trade, but also their stabilities and the static and dynamic Heckscher–Ohlin theorems.
The early years of the Rochester department of economics
Authors: McKenzie Lionel
Published: May 2012

This article describes the early years of the Rochester department of economics.
17‐year outcome of preterm infants with diverse neonatal morbidities: Part 1—Impact on physical, neurological, and psychological health status
Authors: Sullivan Mary C. , Msall Michael E. , Miller Robin J.
Published: May 2012

Purpose.  The purpose of this study was to comprehensively examine physical, neurological, and psychological health in a U.S. sample of 180 infants at age 17.

Design and Methods.  The World Health Organization International Classification of Functioning, Disability and Health model framed the health‐related domains and contextual factors. Assessments included growth, chronic conditions, neurological status, and psychological health.

Results.  Physical health, growth, and neurological outcomes were poorer in the preterm groups. Minor neurological impairment was related to integrative function. Preterm survivors reported higher rates of depression, anxiety, and inattention/hyperactivity.

Practice Implications.  Complex health challenges confront preterm survivors at late adolescence, suggesting the necessity of continued health surveillance.
Joining of AlN to Ceramic Bonded Carbon for Heat Dissipating Substrates
Authors: Chen Weiwu , Tojo Tetsuro , Miyamoto Yoshinari
Published: May 2012

Ceramic bonded carbon (CBC) is a new composite consisting of carbon particles bonded with thin ceramic boundaries. It can not only reinforce carbon but also provide joining capability with other materials. To obtain light‐weight heat dissipating substrates with matched low coefficients of thermal expansion, a top layer of
AlN
and a bottom layer of
AlN
/CBC (20 vol%
AlN
) were sintered and joined in one step by hot‐pressing at 1950°C. Both
AlN
and
AlN
/CBC were densified and bonded tightly.
AlN
/CBC has a density of 2.30 g/cm3, bending strength of 112 MPa, and thermal conductivity of 170 W/mK. The obtained
AlN–AlN
/CBC plates showed a high strength as a result of the direct
AlN–AlN
sintering at the
AlN
and
AlN
/CBC interface.
Social desirability in the selection process: new insights from a novel context
Authors: Li Andrew , Bagger Jessica , Friske Wesley
Published: May 2012

In this study we examined whether past research on social desirability based on western samples could be generalized to a novel environment, such as Singapore. We also investigated whether cultural orientations predict the inflation of personality scores in the selection process and whether they influence the effectiveness of social desirability correction. Using survey data collected at two points from 324 undergraduate business students (166 students from the United States and 158 students from Singapore), the results of this within‐subject design study were mixed. Specifically, while social desirability inflated scores on personality measures, it also increased their criterion validity in Singapore. Additionally, self‐deception enhancement (SDE) predicted the inflation of openness to experience scores in the United States. Finally, in the sample from the United States, correcting for SDE increased the criterion validity of personality measures to a greater extent for those who scored high on horizontal individualism (HI) than it did for those who scored low on HI.
The Molecular Design of S‐Nitrosothiols as Photodynamic Agents for Controlled Nitric Oxide Release
Authors: Giles Niroshini M. , Kumari Sweta , Gang Bevan P. , Yuen Chun W. W. , Billaud Emilie M. F. , Giles Gregory I.
Published: May 2012

Nitric oxide is a small messenger molecule utilized by nature in cell signalling and the non‐specific immune response. At present, nitric oxide releasing prodrugs cannot be efficiently targeted towards a specific body compartment, which restricts their therapeutic applications. To address this limitation, we have designed two photolabile nitric oxide releasing prodrugs, tert‐butyl S‐nitrosothiol and tert‐dodecane S‐nitrosothiol, which are based on the S‐nitrosothiol functionality. By modulating the prodrugs’ hydrophobicity, we postulated that we could increase their stability within the cell by preventing their interaction with hydrophilic thiols and metal ions; processes that are known to inactivate this prodrug class. Our data demonstrate that these prodrugs have improved nitric oxide release kinetics compared to currently available S‐nitrosothiols, as they are highly stable in vitro in the absence of irradiation (t1/2 > 3 h), while their rate of decomposition can be regulated by controlling the intensity or duration of the photostimulus. Nitric oxide release can readily be achieved using non‐laser based light sources, which enabled us to characterize photoactivation as a trigger mechanism for nitric oxide release in A549 lung carcinoma cells. Here we confirmed that irradiation induced highly significant increases in cytotoxicity within a therapeutic drug range (1–100 μm), and the utility of this photoactivation switch opens up avenues for exploring the applications of these prodrugs for chemical biology studies and chemotherapy.
Penetration Study of Formulated Nanosized Titanium Dioxide in Models of Damaged and Sun‐Irradiated Skins
Authors: Miquel‐Jeanjean Corinne , Crépel Frédéric , Raufast Véronique , Payre Bruno , Datas Lucien , Bessou‐Touya Sandrine , Duplan Hélène
Published: May 2012

Inorganic ultraviolet filters such as titanium dioxide (TiO2), safe to use on healthy skin, are often applied on compromised and irradiated skin. The aim of this study was to evaluate in vitro the cutaneous penetration of TiO2 nanoparticles (≥ 20 nm primary size), included in a sunscreen, in intact, damaged, irradiated, and damaged/irradiated pigskin. Cutaneous penetration and localization of TiO2 after a 24‐h sunscreen application were investigated quantitatively using inductively coupled plasma‐mass spectrometry, and qualitatively using transmission electron microscopy (TEM). Elemental identity of the nanoparticles was evaluated by TEM‐coupled Energy Dispersive X‐ray analysis (TEM‐EDX). In intact and damaged/irradiated skins, 102.35 ± 4.20% and 102.84 ± 5.67% of the titanium deposited, respectively, were found at the surface and stratum corneum (SC), whereas only 0.19 ± 0.15% and 0.39 ± 0.39% were found in the viable epidermis and dermis and no titanium was detected in the receptor fluid. TEM‐EDX analysis confirmed the presence of titanium in the aggregates formed by TiO2 at the SC surface, as already characterized in the sunscreen formulation. TiO2 nanoparticles included in a sunscreen thus remain in the uppermost layers of the SC, whether in intact skin or in compromised and/or skin exposed to simulated solar radiation.
Recognition of a core fragment ofBeauveria bassianahydrophobin gene promoter (Phyd1) and its special use in improving fungal biocontrol potential
Authors: Wang Zheng‐Liang , Ying Sheng‐Hua , Feng Ming‐Guang
Published: May 2012

To identify a suitable promoter for use in engineering fungal entomopathogens to improve heterologous gene expression and fungal biocontrol potential, a 1798 bp promoter (Phyd1) upstream ofBeauveria bassianaclass I hydrophobin gene (hyd1) was optimized by upstream truncation and site‐directed mutation. A truncated 1290 bp fragment (Phyd1‐t1) droveeGFPexpression inB. bassianamuch more efficiently than full‐lengthPhyd1. Further truncatingPhyd1‐t1to 1179, 991 and 791 bp or mutating one of the binding domains of three transcription factors inPhyd1‐t1reduced significantly the expression ofeGFP(enhanced green fluorescence protein). UnderPhyd1‐t1control,eGFPwas expressed more abundantly in conidiogenic cells and conidia than in mycelia. Therefore,Phyd1‐t1was used to integrate a bacterium‐derived, insect midgut‐specific toxin (vip3Aa1) gene intoB. bassiana, yielding a transgenic strain (BbHV8) expressing 9.8‐fold more toxin molecules in conidia than a counterpart strain (BbV28) expressing the toxin under the control ofPgpdA, a promoter widely used for gene expression in fungi. Consequently,BbHV8 showed much higherper osvirulence toSpodoptera lituralarvae thanBbV28 in standardized bioassays with normal conidia for both cuticle penetration and ingestion or heat‐killed conidia for ingestion only. Conclusively,Phyd1‐t1is a useful tool for enhancing beneficial protein expression, such asvip3Aa1, in fungal conidia, which are the active ingredients of mycoinsecticides.
Estimation of the optimal brachytherapy utilisation rate in the treatment of vaginal cancer and comparison with patterns of care
Authors: Thompson Stephen R , Delaney Geoff P , Gabriel Gabriel S , Jacob Susannah , Barton Michael B
Published: May 2012

Introduction: Having previously modelled the optimal proportion of uterine cervix and corpus cancers that should be treated with brachytherapy (BT), we aimed to complete the assessment of the role of BT for gynaecological cancers by estimating the optimal proportion of vaginal cancer cases that should be treated with BT, the optimal BT utilisation (BTU) rate for vaginal cancer. We compared this with actual vaginal BTU and assessed quality of BT for vaginal cancer by a Patterns‐of‐Care Study (POCS).

Methods: Evidence‐based guidelines were used to construct an optimal BTU decision tree for vaginal cancer. Searches of the epidemiological literature to ascertain the proportion of patients who fulfilled the criteria for BT were conducted. The robustness of the model was tested by sensitivity analyses and by peer review. A retrospective POCS of BT in New South Wales (NSW) for 2003 was conducted, and actual BTU for vaginal cancer was determined. Differences between optimal and actual BTU were assessed. Quality of BT for vaginal cancer was compared with published benchmarks.

Results: The optimal vaginal cancer BTU rate was estimated to be 85% (range 81–87%). In NSW in 2003, actual vaginal cancer BTU was only 42% (95% confidence interval 22–62%). In NSW, only nine patients were treated, all with intra‐vaginal cylinders, and two of four to lower than recommended doses.

Conclusions: BT for vaginal cancers is underutilised in NSW compared with the proposed optimal models of care. BT quality may have been suboptimal and this may relate to the rarity of this disease.
Malignant struma ovarii: The west of Scotland experience and review of literature with focus on postoperative management
Authors: Shrimali Raj K , Shaikh Ghazia , Reed Nick S
Published: May 2012

Introduction: Malignant struma ovarii is an extremely rare ovarian tumour containing malignant thyroid carcinoma within differentiated thyroid tissue, as the predominant tissue type. Surgery for suspected ovarian tumour and incidental pathological diagnosis is the most common presentation. Evidence supporting any particular approach to the clinical management of this condition is limited, mainly consisting of case reports, small series or pathological case series. There is no randomised evidence for postoperative management in view of the rarity of this condition. The opinion is divided between conservative management versus total thyroidectomy and radio‐iodine ablation.

Methods: We carried out a retrospective review of our series with focus on postoperative management of this rare condition. A review of existing literature was also carried out.

Results: Six patients with a median age of 52 years presented with various symptoms of abdominal pain, pressure or menstrual problems. After the initial gynaecological resection and specialised pathology review, they were subsequently treated with total thyroidectomy and administration of radioactive iodine. All of these six patients are in remission at a median follow up of 60 months.

Conclusion: We favour aggressive postoperative management with total thyroidectomy and radioactive iodine, and long‐term follow up of these patients.
Food for Thought: „Exotisches und Hausmannskost“ zum interkulturellen Lernen
Authors: Eppelsheimer Natalie
Published: May 2012

How can we, in alignment with the ACTFL National Standards for Foreign Language Teaching (2006) or the goals set forward in the Common European Framework of References (2001), and in the context of the 2007 MLA report, advance beginning German learners' intercultural and symbolic competence and produce educated learners who operate with a “transcultural mentality” and social awareness in a multicultural society ? How can we provide opportunities for our students to situate themselves in a dialog with other cultures ? What are our criteria for selecting text with intercultural potential and for developing objectives, instructional goals, and learning activities that foster intercultural learning ? This article suggests some answers to these questions by first providing a summary of current discussions of interculturality and intercultural learning, and then using the short text “Exotisches und Hausmannskost” from Elke Heidenreich's Also column as a model for the application of theoretical considerations of interculturality and intercultural learning and for the selection and didactization of texts with intercultural potential.
Articulating the Curriculum through Cultural Themes: A Literacy and Genre Approach to Teaching Protest, Rebellion, and the Reevaluation of the Past
Authors: Rogers N. Jeff , LeCompte Laurie , Plumly Vanessa
Published: May 2012

Conceived of as a response to the 2007 MLA Report on the state of foreign language teaching and learning in the United States, this article takes up some of the report's recommendations and puts them into practice. The first part of the article offers a response to current debates concerning foreign language programs and lays the conceptual foundation for a unit intended to help bridge the gap between second and third year courses in German Studies. This is followed by a pedagogical unit developed around Gregor Schnitzler's (2002) comedy thriller, Was tun, wenn's brennt? The film provides material for students of German to explore the idea of Vergangenheitsbewältigung (‘coming to terms with the past’) beyond the context of the Nazi period, focusing instead on post‐war periods of German history.
Prevalence of the Bacterium Coxiella burnetii in Wild Rodents from a Canadian Natural Environment Park
Authors: Thompson M. , Mykytczuk N. , Gooderham K. , Schulte‐Hostedde A.
Published: May 2012

Zoonotic diseases impact both wild and domestic animal populations and can be transmitted to humans through close contact with animal species. Reservoir species acting as vectors are major traffickers of disease. Rodents contribute to the transmission of Coxiella burnetii although little is known about its prevalence in wild animal populations. DNA was extracted from genital swabs collected from woodland jumping mice, deer mice, Southern red‐backed voles, Eastern chipmunks, North American red squirrels, as well as Southern and Northern flying squirrels collected from Algonquin Park, Canada. The presence of C. burnetii was determined through real‐time PCR. All species sampled had some prevalence of infection, except Eastern chipmunks, indicating wild rodents in Algonquin Park are reservoirs for C. burnetii. Emerging zoonotic diseases are linked to increasing globalization. Contact amongst individuals increases as crowding, habitat loss and fragmentation increase within wild spaces. Parks often act as a last refuge for wildlife but may also be an important transmission zone of wildlife disease to humans. Investigations that attempt to discover wild reservoir species of zoonotic disease are critically important to understanding the risk of pathogen exchange between wild and human populations.
Remittances and Labour Supply in Post‐Conflict Tajikistan
Authors: Justino Patricia , Shemyakina Olga N.
Published: May 2012

This paper analyzes the impact of remittances on the labour supply of men and women in post‐conflict Tajikistan. We find that on average men and women from remittance‐receiving households are less likely to participate in the labour market and supply fewer hours when they do. The negative effect of remittances on labour supply is smaller for women, which is an intriguing result as other studies on remittances and labour supply (primarily focused on Latin America) have shown that female labour supply is more responsive to remittances. The results are robust to using different measures of remittances and inclusion of variables measuring migration of household members. We estimate a joint effect of remittances and an individual's residence in a conflict‐affected area during the Tajik civil war. Remittances had a larger impact on the labour supply of men living in conflict‐affected areas compared to men in less conflict‐affected areas. The impact of remittances on the labour supply of women does not differ by their residence in both the more or less conflict affected area.
Firm Behaviour and the Introduction of New exports: Evidence from Brazil
Authors: Cirera Xavier , Marin Anabel , Markwald Ricardo
Published: May 2012

This paper contributes to understanding the process of export diversification by analysing firm level determinants in Brazil during the period 2000–2009. The first objective of the paper is to establish the set of firm characteristics and processes that are more conductive to new exports; the second, to identify different pathways to diversification regarding relatedness and sophistication and, which firm level behaviours can be associated to the different paths. We answer these questions using a unique dataset that links data on exports, innovation and firms characteristics at the firm level. The paper contributes to the literature on export diversification and on preparation for exporting by identifying firm level behaviours that contribute to the process of diversification. In particular, the findings suggest that firms prepare for diversification by first gaining power in the domestic market and more importantly that they do so by adopting specific innovation and learning efforts.
Insecurity and Local Governance in Congo's South Kivu
Authors: Mushi Ferdinand Mugumo
Published: May 2012

South Kivu Province of the Democratic Republic of Congo (DRC) has experienced recurrent wars for more than 15 years. This Research Report explores the way local systems of governance and networking in South Kivu have been affected by the civil war and the ways in which local communities have tried to cope with chaos and the absence of the state.

Most community groups in South Kivu consider that violence and conflict were imposed on them and dissociate themselves, as communities, from violence, this being the work of some organised groups which should not be confused with the communities themselves. The fundamental causes of the wars lie in the ways in which Rwanda and Burundi, to different degrees, involved themselves with these other actors.

The report also explores the role of various local organisations and groups in conflict and post‐conflict governance. Governance does not completely disappear when the state collapses. Its structures remain hidden and in retreat, but ready to sprout into existence again. This is especially true for the structures of local and rural governance, and the networks of the church.

South Kivu remains volatile and filled with suspicion. The behaviour of many groups is determined by fear of another cycle of war. When some communities can draw on external backing, the extension of such networks establishes another dimension of distrust.

A post‐conflict state has need of decentralisation. Multi‐layered, networked governance is a reality and is much less of a threat to viable states than might be imagined. However, when the state is incapable of assuring the security of its own population against external threats, when its own protective services engage in arbitrary activities and live off the people, and when impunity goes unchecked, it is difficult for social mechanisms and local institutions alone to substitute for the lack of a functioning state.
Measuring the ‘Inclusivity’ of Inclusive Business
Authors: Wach Elise
Published: May 2012

‘Inclusive Business’ has enormous potential to contribute positively to development outcomes. Working through core business models, the ‘Inclusive Business’ approach requires minimal outside support and can often reach a scale unattainable by most direct development interventions. Take for example, Vodafone's M‐PESA service, which has reached more than 18.5 million individuals since 2007 and continues to be a profitable business model (BCtA 2011).

But when is business ‘inclusive’ and when is it simply business? How does Coca‐Cola's business model in El Salvador contribute more to women's empowerment than its typical approach to selling fizzy drinks? Accurate information about business impacts – direct and indirect, positive and negative – can help practitioners to better identify (and support) the approaches that can most positively contribute to development.

This paper analyses some of the current approaches and frameworks for evaluating ‘Inclusive Business’ impacts. It finds that while they shed light on the complex network of effects that businesses have and the ways in which some firms are attempting to contribute to development, they are unable to provide information about the actual impacts of business activities. More, higher quality, and less partial ‘Inclusive Business’ evaluations are needed to better enable us to harness the potential for business to contribute positively to development.
Using dispersal information to model the species–environment relationship of spreading non‐native species
Authors: Sullivan Martin J. P. , Davies Richard G. , Reino Luís , Franco Aldina M. A.
Published: May 2012

1. Non‐native species can be major drivers of biodiversity loss and cause economic damage. Predicting the potential distribution of a non‐native species, and understanding the environmental factors that limit this distribution, is useful for informing their potential management. This is often carried out using species distribution models (SDMs) that attempt to classify grid cells as suitable or unsuitable for a species based on a set of environmental covariates.

2. A key assumption of SDMs is that a species is in equilibrium with its environment. Spreading non‐native species often violate this assumption due to dispersal limitation.

3. We present a simple method for dealing with this problem: dispersal weighting (DW). This uses the probability that a species can disperse to a grid cell to weight a SDM. We use simulations to compare the ability of DW and unweighted models at parameterising the true species–environment relationship (SER) of a simulated species, and to test their ability at predicting the future distribution of this species. We investigate how varying the degree of spatial autocorrelation in explanatory variables affects the performance of the methods.

4. Dispersal weighting models outperformed unweighted models at parameterising the SER, and at predicting the future distribution of the species when dispersal probabilities were incorporated into the model predictions. Unweighted models had a stronger tendency than DW models to overestimate the magnitude of relationships with spatially autocorrelated explanatory variables, but underestimate the magnitude of relationships with randomly distributed variables.

5. We then applied our method to a real case study, using it to model the distribution of the non‐native common waxbill Estrilda astrild in the Iberian Peninsula as a function of climate and land‐use variables. The relative performance of DW and unweighted models reflected the results of the simulation.

6. We conclude that DW models perform better than unweighted models at modelling the true SER of non‐native species, and recommend using DW whenever enough data exist to create a dispersal model.
Limited‐information goodness‐of‐fit testing of hierarchical item factor models
Authors: Cai Li , Hansen Mark
Published: May 2012

In applications of item response theory, assessment of model fit is a critical issue. Recently, limited‐information goodness‐of‐fit testing has received increased attention in the psychometrics literature. In contrast to full‐information test statistics such as Pearson’s X2 or the likelihood ratio G2, these limited‐information tests utilize lower‐order marginal tables rather than the full contingency table. A notable example is Maydeu‐Olivares and colleagues’M2 family of statistics based on univariate and bivariate margins. When the contingency table is sparse, tests based on M2 retain better Type I error rate control than the full‐information tests and can be more powerful. While in principle the M2 statistic can be extended to test hierarchical multidimensional item factor models (e.g., bifactor and testlet models), the computation is non‐trivial. To obtain M2, a researcher often has to obtain (many thousands of) marginal probabilities, derivatives, and weights. Each of these must be approximated with high‐dimensional numerical integration. We propose a dimension reduction method that can take advantage of the hierarchical factor structure so that the integrals can be approximated far more efficiently. We also propose a new test statistic that can be substantially better calibrated and more powerful than the original M2 statistic when the test is long and the items are polytomous. We use simulations to demonstrate the performance of our new methods and illustrate their effectiveness with applications to real data.
Cells in the monkey ponto‐medullary reticular formation modulate their activity with slow finger movements
Authors: Soteropoulos Demetris S. , Williams Elizabeth R. , Baker Stuart N.
Published: May 2012

Key points

The reticulospinal tract is an important pathway communicating instructions for movement from the brain to the spinal cord

Although the reticulospinal tract is usually associated with gross movements such as postural adjustments and walking, recent work has shown that it also connects to spinal centres involved in hand function

In awake monkeys, we recorded from the origin of the reticulospinal tract (the reticular formation) during performance of a fine finger movement task. Cells modulated their firing during finger movements

Stimulation of sites within the reticular formation sometimes activated hand muscles, and some cells within the reticular formation responded to the sensory input following externally imposed movements of the digits

This work supports a role of the reticulospinal tract in hand function in healthy individuals. Additionally, this tract may be able to mediate some recovery of hand function when other pathways are damaged, such as after stroke

Abstract  Recent work has shown that the primate reticulospinal tract can influence spinal interneurons and motoneurons involved in control of the hand. However, demonstrating connectivity does not reveal whether reticular outputs are modulated during the control of different types of hand movement. Here, we investigated how single unit discharge in the pontomedullary reticular formation (PMRF) modulated during performance of a slow finger movement task in macaque monkeys. Two animals performed an index finger flexion–extension task to track a target presented on a computer screen; single units were recorded both from ipsilateral PMRF (115 cells) and contralateral primary motor cortex (M1, 210 cells). Cells in both areas modulated their activity with the task (M1: 87%, PMRF: 86%). Some cells (18/115 in PMRF; 96/210 in M1) received sensory input from the hand, showing a short‐latency modulation in their discharge following a rapid passive extension movement of the index finger. Effects in ipsilateral electromyogram to trains of stimuli were recorded at 45 sites in the PMRF. These responses involved muscles controlling the digits in 13/45 sites (including intrinsic hand muscles, 5/45 sites). We conclude that PMRF may contribute to the control of fine finger movements, in addition to its established role in control of more proximal limb and trunk movements. This finding may be especially important in understanding functional recovery after brain lesions such as stroke.
Protein S‐glutathionylation enhances Ca2+‐induced Ca2+ release via the IP3 receptor in cultured aortic endothelial cells
Authors: Lock Jeffrey T. , Sinkins William G. , Schilling William P.
Published: May 2012

Key points

In non‐excitable cells, oxidative stress increases inositol 1,4,5‐trisphosphate (IP3) receptor (IP3R) activity, which can cause Ca2+ oscillations under basal conditions and enhance agonist‐stimulated changes in cytosolic free Ca2+ concentration.

Protein S‐glutathionylation, the reversible modification of cysteine thiols by glutathione, is elevated in response to oxidative stress, but the consequence of glutathionylation for IP3R function is not known.

In this study we provide evidence that Ca2+‐induced Ca2+‐release (CICR) via the IP3R is enhanced by oxidant‐induced glutathionylation in cultured aortic endothelial cells.

Our results suggest glutathionylation may represent a fundamental mechanism for regulating IP3R activity during physiological redox signalling and during pathological oxidative stress.

Abstract  In non‐excitable cells, thiol‐oxidizing agents have been shown to evoke oscillations in cytosolic free Ca2+ concentration ([Ca2+]i) by increasing the sensitivity of the inositol 1,4,5‐trisphosphate (IP3) receptor (IP3R) to IP3. Although thiol modification of the IP3R is implicated in this response, the molecular nature of the modification(s) responsible for changes in channel activity is still not well understood. Diamide is a chemical oxidant that selectively converts reduced glutathione (GSH) to its disulfide (GSSG) and promotes the formation of protein–glutathione (P‐SSG) mixed disulfide, i.e. glutathionylation. In the present study, we examined the effect of diamide, and the model oxidant hydrogen peroxide (H2O2), on oscillations in [Ca2+]i in fura‐2‐loaded bovine (BAECs) and human (HAECs) aortic endo‐thelial cells using time‐lapse fluorescence video microscopy. In the absence of extracellular Ca2+, acute treatment with either diamide or H2O2 increased the number of BAECs exhibiting asynchronous Ca2+ oscillations, whereas HAECs were unexpectedly resistant. Diamide pretreatment increased the sensitivity of HAECs to histamine‐stimulated Ca2+ oscillations and BAECs to bradykinin‐stimulated Ca2+ oscillations. Moreover, in both HAECs and BAECs, diamide dramatically increased both the rate and magnitude of the thapsigargin‐induced Ca2+ transient suggesting that Ca2+‐induced Ca2+ release (CICR) via the IP3R is enhanced by glutathionylation. Similar to diamide, H2O2 increased the sensitivity of HAECs to both histamine and thapsigargin. Lastly, biochemical studies showed that glutathionylation of native IP3R1 is increased in cells challenged with H2O2. Collectively our results reveal that thiol‐oxidizing agents primarily increase the sensitivity of the IP3R to Ca2+, i.e. enhanced CICR, and suggest that glutathionylation may represent a fundamental mechanism for regulating IP3R activity during physiological redox signalling and during pathologicalical oxidative stress.
GluN1 splice variant control of GluN1/GluN2D NMDA receptors
Authors: Vance Katie M. , Hansen Kasper B. , Traynelis Stephen F.
Published: May 2012

Key points

NMDA receptors are ionotropic glutamate receptors that mediate the slow component of excitatory synaptic transmission in the central nervous system.

GluN1‐1a/GluN2D receptors, in which the GluN1 subunit does not contain exon‐5 encoded residues in the amino‐terminal domain, previously have been shown to have a low open probability and an exceptionally slow deactivation time course.

In this study, we report that GluN1 splice variants containing residues encoded by exon 5 in their amino‐terminal domain influence agonist potencies, deactivation time course, and single channel properties of GluN2D‐containing NMDA receptors.

We also show a model of NMDA receptor gating that can describe the key characteristics of the single channel and macroscopic current responses of GluN1/GluN2D NMDA receptors.

These data demonstrate that the GluN1 amino‐terminal domain is an important determinant in the kinetic and pharmacological properties of GluN2D‐containing NMDA receptors.

Abstract  NMDA receptors are ionotropic glutamate receptors that mediate a slow, Ca2+‐permeable component of excitatory synaptic transmission in the central nervous system. Recombinant GluN1‐1a/GluN2D receptors are characterized by low channel open probability and prolonged deactivation time course following the removal of agonist. Here, we show that the deactivation time course, agonist potency, and single channel properties of GluN2D‐containing NMDA receptors are modulated by alternative RNA splicing of GluN1. Our results demonstrate that GluN1 exon 5, which encodes a 21‐amino‐acid insert in the amino‐terminal domain, is a key determinant of GluN1/GluN2D receptor function. GluN1‐1b/GluN2D receptors, which contain the residues encoded by exon 5, deactivate with a dual exponential time course described by a τFAST of 410 ms and a τSLOW of 1100 ms. This time course is 3‐fold more rapid than that for exon 5‐lacking GluN1‐1a/GluN2D, which deactivates with a τFAST of 1100 ms and a τSLOW of 3400 ms. Exon 5‐containing NMDA receptors also have a two‐fold higher open probability (0.037) than exon 5‐lacking receptors (0.017). Furthermore, inclusion of exon 5‐encoded residues within the GluN1‐1b subunit decreases the potency for the endogenous agonist l‐glutamate. Evaluation of receptor kinetics for NMDA receptors containing mutated GluN1‐1b subunits and wild‐type GluN2D identified residue Lys211 in GluN1‐1b as a key determinant of exon 5 control of the deactivation time course and glutamate potency. Evaluation of a kinetic model of GluN1/GluN2D gating suggests that residues encoded by exon 5 influence several rate‐limiting steps. These data demonstrate that the GluN1 subunit is a key determinant of the kinetic and pharmacological properties of GluN2D‐containing NMDA receptors.
Deficiency of sphingomyelin synthase‐1 but not sphingomyelin synthase‐2 causes hearing impairments in mice
Authors: Lu Mei‐Hong , Takemoto Makoto , Watanabe Ken , Luo Huan , Nishimura Masataka , Yano Masato , Tomimoto Hidekazu , Okazaki Toshiro , Oike Yuichi , Song Wen‐Jie
Published: May 2012

Key points

Sphingomyelin (SM) is a structural component of plasma membrane and may participate in signal transduction. The role of SM metabolism in hearing remains controversial.

Here we examined hearing in mice deficient of SM synthase‐1 (SMS1) or SMS2, and show that only deficiency of SMS1 causes hearing loss.

The hearing loss in SMS1 knockout mice is attributable at least in part to a reduction of endocochlear potential.

The reduction of endocochlear potential is attributable at least in part to atrophy of the cochlear stria vascularis and its altered expression of K+ channels.

Our results establish that SMS1 is essential for normal inner ear function.

Abstract  Sphingomyelin (SM) is a sphingolipid reported to function as a structural component of plasma membranes and to participate in signal transduction. The role of SM metabolism in the process of hearing remains controversial. Here, we examined the role of SM synthase (SMS), which is subcategorized into the family members SMS1 and SMS2, in auditory function. Measurements of auditory brainstem response (ABR) revealed hearing impairment in SMS1−/− mice in a low frequency range (4–16 kHz). As a possible mechanism of this impairment, we found that the stria vascularis (SV) in these mice exhibited atrophy and disorganized marginal cells. Consequently, SMS1−/− mice exhibited significantly smaller endocochlear potentials (EPs). As a possible mechanism for EP reduction, we found altered expression patterns and a reduced level of KCNQ1 channel protein in the SV of SMS1−/− mice. These mice also exhibited reduced levels of distortion product otoacoustic emissions. Quantitative comparison of the SV atrophy, KCNQ1 expression, and outer hair cell density at the cochlear apical and basal turns revealed no location dependence, but more macrophage invasion into the SV was observed in the apical region than the basal region, suggesting a role of cochlear location‐dependent oxidative stress in producing the frequency dependence of hearing loss in SMS1−/− mice. Elevated ABR thresholds, decreased EPs, and abnormal KCNQ1 expression patterns in SMS1−/− mice were all found to be progressive with age. Mice lacking SMS2, however, exhibited neither detectable hearing loss nor changes in their EPs. Taken together, our results suggest that hearing impairments occur in SMS1−/− but not SMS2−/− mice. Defects in the SV with subsequent reductions in EPs together with hair cell dysfunction may account, at least partially, for hearing impairments in SMS1−/− mice.
Experimental and Computational Investigations to Evaluate the Effects of Fluid Viscosity and Particle Size on Erosion Damage
Authors: Okita Risa , Zhang Yongli , McLaury Brenton S. , Shirazi Siamack A.
Published: May 2012

Zhang et al. (2006) utilized computational fluid dynamics (CFD) to examine the validity of erosion models that have been implemented into CFD codes to predict solid-particle erosion in air and water for inconel 625. This work is an extension of Zhang’s work and is presented as a step toward obtaining a better understanding of the effects of fluid viscosity and sand-particle size on measured and calculated erosion ratios, where erosion ratio is defined as the ratio of mass loss of material to mass of solid particles. The erosion ratios of aluminum 6061-T6 were measured for direct impingement conditions of a submerged jet. Fluid viscosities of 1, 10, 25, and 50 cP and sand-particle sizes of 20, 150, and 300 μm were tested. The average fluid speed of the jet was maintained at 10 m/s. Erosion data show that erosion ratios for the 20- and 150-μm particles are reduced as the viscosity is increased, whereas, surprisingly, the erosion ratios for the 300-μm particles do not seem to change much for the higher viscosities. For all viscosities considered, larger particles produced higher erosion ratios, for the same mass of sand, than smaller particles. Concurrently, an erosion equation has been generated based on erosion testing of the same material in air. The new erosion model has been compared to available models and has been implemented into a commercially available CFD code to predict erosion ratios for a variety of flow conditions, flow geometries, and particle sizes. Because particle speed and impact angle greatly influence erosion ratios of the material, calculated particle speeds were compared with measurements. Comparisons reveal that, as the particles penetrate the near wall shear layer, particles in the higher viscosity liquids tend to slow down more rapidly than particles in the lower viscosity liquids. In addition, CFD predictions and particle-speed measurements are used to explain why the erosion data for larger particles is less sensitive to the increased viscosities.
Cylinder Liner in Ductile Cast Iron for High Loaded Combustion Diesel Engines
Authors: Rejowski Edney Deschauer , Soares Edmo , Roth Ingo , Rudolph Steffen
Published: May 2012

With the increase of combustion loading and the trend to reduce engine size, there is a need for thinner but stronger wet cylinder liners. While most of the current cylinder liners are made of gray cast iron, due to its good tribological behavior, machinability performance, and competitive price, alternative casting materials such as compact graphite iron, ductile iron, and even steel are being considered to address future engine demands. In this paper, a new ductile iron (DI) cast material for wet cylinder liners is presented. The material has about 60 and 70% higher limits, respectively, for tensile stress and fatigue resistance as compared to conventional gray cast irons, but without a penalty on the tribological properties. There is also a potential improvement to avoid cavitation on the outside surface due to its higher young modulus, which also equates to a higher stiffness.

The tested cylinder liners were induction hardened on the running surface and a slide hone process was used to improve wear and scuffing resistance. The liners were tested in a heavy duty diesel (HDD) engine with a peak cylinder pressure (PCP) of 245 bar and showed similar wear as observed with conventional cylinder liners of gray cast iron material. The DI cylinder liners were also tested in an abusive scuffing engine test without any concern. The improved mechanical properties of the described new DI material introduce possibilities to reduce the liner wall thickness or increase specific output. The preliminary evaluation in this paper showed that this new material is feasible for HDD diesel engines with a PCP up to 250 bar. In cases where the customer needs to increase the bore diameter for output reasons there is the potential to reduce the liner wall thickness by up to 25% based on high mechanical properties (UTS, Young’s modulus and fatigue strength). In both cases, a FEA analysis to support the new component design is recommended.
A Porous Media Approach for Analyzing a Countercurrent Dialyzer System
Authors: Sano Yoshihiko , Nakayama Akira
Published: May 2012

A porous media approach based on the volume-averaging theory has been proposed to investigate solute diffusion and ultrafiltration processes associated with hemodialysis using a hollow fiber membrane dialyzer. A general set of macroscopic governing equations has been derived for the three individual phases, namely, the blood phase, the dialysate phase, and the membrane phase. Thus, conservations of mass, momentum, and species are considered for blood compartments, dialysate compartments, and membranes within a dialyzer to establish a three concentration equation model. These macroscopic equations can be simultaneously solved for the various cases of inlet velocities of blood and dialysate. An analytic expression for the solute clearance was obtained for the one-dimensional case, in which important dimensionless parameters controlling the dialyzer system are identified for the first time.
Intelligent Image-Based Gas-Liquid Two-Phase Flow Regime Recognition
Authors: Ghanbarzadeh Soheil , Hanafizadeh Pedram , Hassan Saidi Mohammad
Published: May 2012

Identification of different flow regimes in industrial systems operating under two-phase flow conditions is necessary in order to safely design and optimize their performance. In the present work, experiments on two-phase flow have been performed in a large scale test facility with the length of 6 m and diameter of 5 cm. Four main flow regimes have been observed in vertical air-water two-phase flow at moderate superficial velocities of gas and water namely: Bubbly, Slug, Churn, and Annular. An image processing technique was used to extract information from each picture. This information includes the number of bubbles or objects, area, perimeter, as well as the height and width of objects (second phase). In addition, a texture feature extraction procedure was applied to images of different regimes. Some features which were adequate for regime identification were extracted such as contrast, energy, entropy, etc. To identify flow regimes, a fuzzy interface was introduced using characteristic of second phase in picture. Furthermore, an Adaptive Neuro Fuzzy (ANFIS) was used to identify flow patterns using textural features of images. The experimental results show that these methods can accurately identify the flow patterns in a vertical pipe.