bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of leaf photosynthetic capacity through increased stomatal density in Arabidopsis
Authors: Tanaka Yu , Sugano Shigeo S. , Shimada Tomoo , Hara‐Nishimura Ikuko
Published: February 2013

Photosynthetic rate is determined by CO2 fixation and CO2 entry into the plant through pores in the leaf epidermis called stomata. However, the effect of increased stomatal density on photosynthetic rate remains unclear. This work investigated the effect of alteration of stomatal density on leaf photosynthetic capacity in Arabidopsis thaliana.

Stomatal density was modulated by overexpressing or silencing STOMAGEN, a positive regulator of stomatal development. Leaf photosynthetic capacity and plant growth were examined in transgenic plants.

Increased stomatal density in STOMAGEN‐overexpressing plants enhanced the photosynthetic rate by 30% compared to wild‐type plants. Transgenic plants showed increased stomatal conductance under ambient CO2 conditions and did not show alterations in the maximum rate of carboxylation, indicating that the enhancement of photosynthetic rate was caused by gas diffusion changes. A leaf photosynthesis‐intercellular CO2 concentration response curve showed that photosynthetic rate was increased under high CO2 conditions in association with increased stomatal density. STOMAGEN overexpression did not alter whole plant biomass, whereas its silencing caused biomass reduction.

Our results indicate that increased stomatal density enhanced leaf photosynthetic capacity by modulating gas diffusion. Stomatal density may be a target trait for plant engineering to improve photosynthetic capacity.
ALFIN‐LIKE 6 is involved in root hair elongation during phosphate deficiency in Arabidopsis
Authors: Chandrika Nulu Naga Prafulla , Sundaravelpandian Kalaipandian , Yu Su‐May , Schmidt Wolfgang
Published: February 2013

Phosphate (Pi) starvation in plants induces dense and elongated root hairs, which increase the absorptive surface area of the roots and play a critical role in Pi uptake. The molecular mechanism underlying these changes remains unclear.

Forward and reverse genetic approaches were employed to identify novel genes involved in root hair formation on Pi starvation.

The mutant per2, with defects in root hair elongation specifically under low Pi conditions, was identified in a large‐scale genetic screen of T‐DNA insertion lines. The phenotype was caused by a mutation in the homeodomain protein ALFIN‐LIKE 6 (AL6). From a screen of mutants defective in genes that showed lower transcript abundance in per2 relative to wild‐type roots on low Pi medium, we identified four putative downstream targets of AL6, namely ETC1, NPC4, SQD2 and PS2, all of which were critical in root hair elongation of Pi‐deficient plants. The results further indicate that AL6 is involved in the control of growth and several key responses to Pi starvation.

Our findings demonstrate that AL6 controls the transcription of a suite of genes critical for root hair elongation under low Pi conditions, suggesting a novel physiological function for an Alfin gene in Arabidopsis.
Diagnosis, prognosis and awareness of dying in nursing homes: towards the Gold Standard?
Authors: Johnson Martin , Attree Moira , Jones Ian , Al Gamal Ekhlas , Garbutt David
Published: February 2013

Background

In Western society and increasingly elsewhere, death has become medicalised and ‘hospitalised’ even when people are enduring deteriorating terminal conditions such as dementia and heart failure. In an attempt to rationalise and dignify the place and manner of death, evidence is emerging that the adoption of end‐of‐life care pathways and models can improve the experience of the end‐of‐life care across a range of care settings. Each of these demands skills and knowledge in the assessment and prediction of the dying trajectory.

Aim

In this study, we report complexities facing relatives, residents and nursing home staff in the awareness, diagnosis and prediction of the dying trajectory.

Methods

Data were collected and analysed within a broadly qualitative methodology. The contexts were two nursing homes in the Greater Manchester area, each at different stages of implementing ‘Gold Standards Framework’ approaches to planning end‐of‐life care with residents and their relatives. From 2008 to 2011 and with appropriate consent, data were collected by a mixture of interviews and participant observation with residents, relatives and staff. Appropriate ethics approvals were sought and given.

Results

Key emerging themes were diagnosis and awareness of dying in which there is no substitute for experience. Significant resource is needed to engage staff, residents and relatives/carers with the idea of advance care planning.

Conclusions

Talking to residents and relatives about their feelings and wishes for care at the end of life remains especially difficult, but education and training in key skills and knowledge can engender confidence. Challenges include diagnosing and predicting dying trajectories.

Implications for practice

Advance care planning can reduce the distress from and number of inappropriate hospital admissions, but requires determination and consistent application of the approach. This can be very challenging in the face of staff rotation and the unpredictability both of the dying trajectory and the decision‐making of some out of hours medical staff.
Impact of Body Mass Index on Atrial Fibrillation Recurrence: A Meta‐analysis of Observational Studies
Authors: GUIJIAN LIU , JINCHUAN YAN , RONGZENG DU , JUN QIAN , JUN WU , WENQING ZHU
Published: February 2013

Background

Obesity is associated with increased risk of atrial fibrillation (AF). Several trials exploring the impact of elevated body mass index (BMI) on the catheter ablation of AF have been published and yield conflicting results. We thus conducted a meta‐analysis to explore the association between elevated BMI and AF recurrence in patients undergoing catheter ablation.

Methods

A systematic review and meta‐analysis was performed. Relative risks (RRs) and 95% confidence intervals (CIs) were pooled.

Results

Six observational studies including 2,358 patients were included. Of those, four studies were prospective cohort studies, and two were retrospective studies. Elevated BMI increased the risk of AF recurrence compared to normal BMI by 31%, where the difference between the two arms was statistically significant (RR = 1.308, 95% CI: 1.036–1.651, P = 0.02). Compared to normal BMI group, the overweight group had a 27% increased risk of AF recurrence (RR = 1.270, 95% CI 0: 961–1.679, P = 0.093) and the obese group had a significantly increased risk of AF recurrence (RR = 1.378, 95% CI: 1.006–1.887, P = 0.045). When compared to the overweight group, the obese group has a 12% increased risk of AF recurrence (RR = 1.116, 95% CI: 0.866–1.438, P = 0.397).

Conclusions

Elevated BMI is associated significantly with AF recurrence in patients undergoing catheter ablation. There is a graded relationship between elevated BMI and increased risk of AF recurrence.
Behavioral Interventions in Patients with an Implantable Cardioverter Defibrillator: Lessons Learned and Where to Go from Here?
Authors: HABIBOVIĆ MIRELA , BURG MATTHEW M. , PEDERSEN SUSANNE S.
Published: February 2013

Background

The implantable cardioverter defibrillator (ICD) is the first‐line treatment for primary and secondary prevention of sudden cardiac death. A subgroup of patients experience psychological distress postimplant, and no clear evidence base exists regarding how best to address patients’ needs. The aim of this critical review is to provide an overview of behavioral interventions in ICD patients to date, and to delineate directions for future research using lessons learned from the ongoing RISTA and WEBCARE trials.

Methods

We searched the PubMed and PsycInfo databases to identify reports of behavioral trials targeting distress and related factors in ICD patients published between 1980 and April 2012.

Results

We identified 17 trials for the review. Generally, compared to usual care, behavioral interventions were associated with reduced anxiety and depression and improved physical functioning, with effect sizes ranging from small to moderate‐large (0.10–1.79 for anxiety; 0.23–1.20 for depression). Important limitations were small sample sizes and potential selection bias, hampering generalizability of the results. In addition to a need for larger trials, experiences from the RISTA and WEBCARE trials suggest that intervention trials tailored to the individual patient may be the way forward.

Conclusions

Behavioral interventions show promise with respect to reducing distress in ICD patients. Large‐scale intervention trials targeted to the individual needs and preferences of patients are warranted, as a “one size fits all” approach is unlikely to work for all ICD patients.
Age‐Related Prognosis of Syncope Associated with a Preexcitation Syndrome
Authors: BREMBILLA‐PERROT BÉATRICE , ZINSCH ANNE M. , SELLAL JEAN M. , ZINZIUS PIERRE Y. , SCHWARTZ JÉRÔME , BEURRIER DANIEL , DE CHILLOU CHRISTIAN , GODENIR JEAN P. , LETHOR JEAN P. , MARCHAL CÉCILE , CLOEZ JEAN L. , PAURIAH MAHESHWAR , NOSU RADU , ANDRONACHE MARIUS , MARÇON FRANÇOIS
Published: February 2013

Background

Syncope in Wolff‐Parkinson‐White syndrome (WPW) is without relationship with WPW or reveals a poorly tolerated arrhythmia. Electrophysiologic study (EPS) is recommended. The purpose of the study was to evaluate the influence of the patient's age on the causes and prognosis of syncope.

Methods

A total of 98 patients, mean age 35 ± 18 years, with WPW were admitted for syncope. Note that 29 were aged between 9 and 19 years (mean 15 ± 3) (children and teenagers/group I), 45 between 20 and 49 years (mean 34 ± 8) (adults/group II), and 24 between 50 and 70 years (mean 60 ± 8) (elderly/group III). EPS consisted of atrial pacing and programmed atrial stimulation in control state and after isoproterenol.

Results

Potentially malignant form (rapid conduction in accessory pathway >240 beats/min in control state or >300 beats/min after isoproterenol and atrial fibrillation [AF] induction) was more frequent in group I (34%) than in groups II (7%) (P < 0.002) and III (0%) (P < 0.001). Orthodromic atrioventricular reentrant tachycardia (AVRT) and AF were induced as frequently in groups I (59, 34%), II (47, 15.5%), and III (54, 17%). AVRT was induced in all but one patient with malignant form. EPS was as frequently negative in groups I (27.5%), II (44%), and III (37.5%). Natural follow‐up (mean 8 ± 6 years) indicated a favorable prognosis, only related to AVRT induction. Induced AF was without significance.

Conclusions

Data in syncope and WPW syndrome depended on age: electrophysiological malignant form was frequent in children/teenagers, rare in adults, and absent in elderly. AVRT, the main cause of syncope, was as frequent in all ranges of age. AF's induction alone had no significance. Final prognosis was favorable.
Effects of Right Ventricular Nonapical Pacing on Cardiac Function: A Meta‐analysis of Randomized Controlled Trials
Authors: WEIZONG WANG , ZHONGSU WANG , YUJIAO ZHANG , MEI GAO , JIANGRONG WANG , YONG ZHANG , XINXING XIE , YINGLONG HOU
Published: February 2013

Background

A meta‐analysis of randomized controlled trials (RCTs) was conducted to compare the effects of right ventricular nonapical (RVNA) and right ventricular apical (RVA) pacing on cardiac function.

Methods

A systematic literature search was performed using MEDLINE, EMBASE, and the Cochrane Library to identify RCTs comparing RVNA pacing with RVA pacing with follow‐up ≥2 months. Twenty RCTs involving 1,114 patients were included.

Results

Compared with RVA pacing, RVNA (mainly right ventricular septum [RVS]) pacing exhibited not only excellent pacing threshold and R‐wave amplitude but also higher impedance. RVNA pacing showed a significant increase in left ventricular ejection fraction (LVEF) at the end of follow‐up (weighted mean difference = 3.58, 95% confidence interval = 1.80–5.35), and the effects were observed in the following subgroups: 6‐month follow‐up, ≤12‐month follow‐up, >12‐month follow‐up, baseline LVEF ≤45%, and baseline LVEF >45%. RVS and RVA pacing significantly differed in improving LVEF (weighted mean difference = 4.82, 95% confidence interval = 2.78–6.87). In addition, RVNA pacing resulted in a narrower QRS duration, a smaller left ventricular end‐systolic volume, and a lower New York Heart Association functional class.

Conclusions

This meta‐analysis found that RVNA (mainly RVS) pacing exhibited satisfactory long‐term lead performance compared with RVA pacing and demonstrated beneficial effects in improving LVEF after the 6‐month follow‐up. Furthermore, it proved superior to RVA pacing in terms of interventricular synchrony and cardiac function.
Use of Asymmetric Bidirectional Catheters with Different Curvature Radius for Catheter Ablation of Cardiac Arrhythmias
Authors: MANTZIARI LILIAN , SUMAN‐HORDUNA IRINA , GUJIC MARKO , JONES DAVID G. , WONG TOM , MARKIDES VIAS , FORAN JOHN P. , ERNST SABINE
Published: February 2013

Background

The impact of recently introduced asymmetric bidirectional ablation catheters on procedural parameters and acute success rates of ablation procedures is unknown.

Methods

We retrospectively analyzed data regarding ablations using a novel bidirectional catheter in a tertiary cardiac center and compared these in 1:5 ratio with a control group of procedures matched for age, gender, operator, and ablation type.

Results

A total of 50 cases and 250 controls of median age 60 (50–68) years were studied. Structural heart disease was equally prevalent in both groups (39%) while history of previous ablations was more common in the study arm (54% vs 30%, P = 0.001). Most of the ablation cases were for atrial fibrillation (46%), followed by atrial tachycardia (28%), supraventricular tachycardia (12%), and ventricular tachycardia (14%). Median procedure duration was 128 (52–147) minutes with the bidirectional, versus 143 (105–200) minutes with the conventional catheter (P = 0.232), and median fluoroscopy time was 17 (10–34) minutes versus 23 (12–39) minutes, respectively (P = 0.988). There was a trend toward a lower procedure duration for the atrial tachycardia ablations, 89 (52–147) minutes versus 130 (100–210) minutes, P = 0.064. The procedure was successfully completed in 96% of the bidirectional versus 84% of the control cases (P = 0.151). A negative correlation was observed between the relative fluoroscopy duration and the case number (r = –0.312, P = 0.028), reflecting the learning curve for the bidirectional catheter.

Conclusions

The introduction of the bidirectional catheter resulted in no prolongation of procedure parameters and similar success rates, while there was a trend toward a lower procedure duration for atrial tachycardia ablations.
The role of anthocyanin in photoprotection and its relationship with the xanthophyll cycle and the antioxidant system in apple peel depends on the light conditions
Authors: Chen Changsheng , Li Houhua , Zhang Di , Li Pengmin , Ma Fengwang
Published: February 2013

The synthesis of anthocyanin, the xanthophyll cycle, the antioxidant system and the production of active oxygen species (AOS) were compared between red and non‐red apple cultivars, in response to either long‐term sunlight exposure (high light intensity) during fruit development, or to exposure of bagged fruits to lower light intensity late in fruit development. During fruit development of red and non‐red apples, the xanthophyll cycle pool size decreased much more in red apple peel late in development. With accumulation of AOS induced by long‐term sunlight exposure, enhancement of the antioxidant system was found. However, this change became significantly lower in red apple than non‐red apple as fruit developed, which might serve to accelerate the anthocyanin synthesis in red apple peel. When, late in fruit development, bagged fruits were exposed to sunlight, the accumulation of AOS was lower in red apple peel than in non‐red peel. This could be due to the higher anthocyanin concentration in the red peels. Meanwhile, compared with that in non‐red cultivar, the xanthophyll cycle and the antioxidant system in red apple peel were protected first but then down‐regulated by its higher anthocyanin concentration during sunlight exposure. In conclusions, red and non‐red apples peel possess different photoprotective mechanisms under high light conditions. The relationship between anthocyanin synthesis and the xanthophyll cycle, and the antioxidant system, depends on the light conditions that fruit undergoes.
A Comparison of Vegetation and Ground‐Dwelling Ants in Abandoned and Restored Gullies and Landslide Surfaces in the Western Colombian Andes
Authors: Calle Zoraida , Henao‐Gallego Natalia , Giraldo Carolina , Armbrecht Inge
Published: February 2013

Landslides and gullies are two common manifestations of land degradation in the densely populated Colombian Andes. In these unstable areas, further mass movements pose a serious threat to local populations and cause off‐site environmental damage through sedimentation, pollution, and increased flooding. A novel approach for restoring severely eroded slopes combines the use of stabilization structures made with stalks of Guadua angustifolia Kunth, Poaceae (bamboo), with high‐density planting of species that exhibit quick growth and sprouting. This study compared the vegetation and ground‐dwelling ant assemblages of 10 pairs of gullies, each pair formed by one enhanced and one untreated or control gully, 6–8 years after restoration or abandonment. The restoration treatment had significant effects on the complexity of vegetation. Average values for plant species richness, basal area, stem density, foliage density index, and total vegetation volume were 11.6, 140, 30, 11.5, and 15.6 times larger, respectively, in enhanced than in control gullies. Mirroring the differences in vegetation, average ant species richness was significantly larger (13 vs. 7.6 species per gully), and a higher proportion of ant species nested within enhanced than control gullies (52.5 vs. 30%). While control gullies were dominated by generalist ants such as Ectatomma ruidum and Linepithema angulatum, enhanced gullies had more specialized ground‐dwelling species, normally associated with high plant cover and abundant leaf litter such as Octostruma balzani and Heteroponera inca. We conclude that this restoration strategy promotes a fast recovery of vegetation and the ground‐dwelling ant fauna in these tropical mountains.
Diversity and Distribution of Floral Resources Influence the Restoration of Plant–Pollinator Networks on a Reclaimed Strip Mine
Authors: Cusser Sarah , Goodell Karen
Published: February 2013

Plant–pollinator mutualisms are one of the several functional relationships that must be reinstated to ensure the long‐term success of habitat restoration projects. These mutualisms are unlikely to reinstate themselves until all of the resource requirements of pollinators have been met. By meeting these requirements, projects can improve their long‐term success. We hypothesized that pollinator assemblage and structure and stability of plant–pollinator networks depend both on aspects of the surrounding landscape and of the restoration effort itself. We predicted that pollinator species diversity and network stability would be negatively associated with distance from remnant habitat, but that local floral diversity might rescue pollinator diversity and network stability in locations distant from the remnant. We created plots of native prairie on a reclaimed strip mine in central Ohio, U.S.A. that ranged in floral diversity and isolation from the remnant habitat. We found that the pollinator diversity declined with distance from the remnant habitat. Furthermore, reduced pollinator diversity in low floral diversity plots far from the remnant habitat was associated with loss of network stability. High floral diversity, however, compensated for losses in pollinator diversity in plots far from the remnant habitat through the attraction of generalist pollinators. Generalist pollinators increased network connectance and plant‐niche overlap. As a result, network robustness of high floral diversity plots was independent of isolation. We conclude that the aspects of the restoration effort itself, such as floral community composition, can be successfully tailored to incorporate the restoration of pollinators and improve success given a particular landscape context.
The Lipid Composition and Physical Properties of the Yeast Vacuole Affect the Hemifusion–Fusion Transition
Authors: Karunakaran Surya , Fratti Rutilio A.
Published: February 2013

Yeast vacuole fusion requires the formation of SNARE bundles between membranes. Although the function of vacuolar SNAREs is controlled in part by regulatory lipids, the exact role of the membrane in regulating fusion remains unclear. Because SNAREs are membrane‐anchored and transmit the force required for fusion to the bilayer, we hypothesized that the lipid composition and curvature of the membrane aid in controlling fusion. Here, we examined the effect of altering membrane fluidity and curvature on the functionality of fusion‐incompetent SNARE mutants that are thought to generate insufficient force to trigger the hemifusion–fusion transition. The hemifusion–fusion transition was inhibited by disrupting the 3Q:1R stoichiometry of SNARE bundles with the mutant SNARE Vam7pQ283R. Similarly, replacing the transmembrane domain of the syntaxin homolog Vam3p with a lipid anchor allowed hemifusion, but not content mixing. Hemifusion‐stalled reactions containing either of the SNARE mutants were stimulated to fuse with chlorpromazine, an amphipathic molecule that alters membrane fluidity and curvature. The activity of mutant SNAREs was also rescued by the overexpression of SNAREs, thus multiplying the force transferred to the membrane. Thus, we conclude that either increasing membrane fluidity, or multiplying SNARE‐generated energy restored the fusogenicity of mutant SNAREs that are stalled at hemifusion. We also found that regulatory lipids differentially modulated the complex formation of wild‐type SNAREs. Together, these data indicate that the physical properties and the lipid composition of the membrane affect the function of SNAREs in promoting the hemifusion–fusion transition.
Mast cells are present in the choroid of the normal eye in most vertebrate classes
Authors: McMenamin Paul Gerard , Polla Emily
Published: February 2013

Objective

Mast cells are bone marrow‐derived tissue‐homing leukocytes, which have traditionally been regarded as effector cells in allergic disorders, responses against parasites, and regulation of blood flow, but a broader perspective of their functional heterogeneity, such as immunomodulation, angiogenesis, tissue repair, and remodeling after injury, is now emerging. The persistence of mast cells in connective tissues throughout the evolution of vertebrates is evidence of strong selective pressure suggesting that these cells must have multiple beneficial and important roles in normal homeostasis. While mast cells are present within the uveal tract of eutherian mammals, there is little known about their presence in the choroid of other vertebrate classes.

Animals studied

Eye tissues from a range of vertebrate species (fish, amphibian, reptiles, birds, marsupials, monotreme, and eutherian mammals) were investigated. Tissues were fixed in either 2% glutaraldehyde, 2% paraformaldehyde or a mixture of both and processed for resin embedding. Semi‐thin sections of the retina and choroid were cut and stained with toluidine blue.

Results and conclusions

Mast cells were identified in the choroid of all classes of vertebrates investigated except sharks. Their morphology, location, and staining characteristics were remarkably similar from teleost fish through to eutherian mammals and bore close morphological resemblance to mammalian connective tissue mast cells. The similar morphology and distribution of mast cells in the choroid of all vertebrate classes studied suggest a basic physiological function that has been retained since the evolution of the vertebrate eye.
BMP‐7 attenuates TGF‐β1–induced fibroblast‐like differentiation of rat dermal papilla cells
Authors: Bin Shu , Li Hou‐Dong , Xu Ying‐Bin , Qi Shao‐Hai , Li Tian‐Zeng , Liu Xu‐Sheng , Tang Jin‐Ming , Xie Ju‐Lin
Published: February 2013

Dermal papilla cells (DPCs) show phenotypic plasticity during wound healing. The multipotency of DPCs is well recognized, but the signaling pathways that regulate the differentiation of these cells into fibroblasts are poorly understood. A preliminary experiment showed that transforming growth factor beta1 (TGF‐β1) can induce DPCs to differentiate into fibroblast‐like cells, which suggests that DPCs may be a source of wound‐healing fibroblasts. Bone morphogenetic protein‐7 (BMP‐7), a member of the TGF‐β superfamily, can prevent and reverse fibrosis by counteracting the TGF‐β1–mediated profibrotic effect. To determine whether BMP‐7 attenuates the TGF‐β1–induced differentiation of DPCs into fibroblasts, we established an in vitro system for DPC differentiation and recorded the gene expression patterns that distinguished DPCs from fibroblasts. The proportion of fibroblast‐like cells was significantly enhanced in DPCs treated with TGF‐β1, as evidenced by immunocytochemistry, flow cytometry, quantitative real‐time reverse transcriptase polymerase chain reaction, and Western blot analysis. BMP‐7 and TGF‐β1 administration substantially decreased fibroblast‐like differentiation, indicating inhibition of TGF‐β1–induced differentiation. The antagonistic BMP‐7– and TGF‐β1–activated signaling pathways can be used to promote wound healing or suppress hypertrophic scarring.
Impaired tissue regeneration corresponds with altered expression of developmental genes that persists in the metabolic memory state of diabetic zebrafish
Authors: Sarras Michael P. , Leontovich Alexey A. , Olsen Ansgar S. , Intine Robert V.
Published: February 2013

As previously reported by our laboratory, streptozocin‐induced diabetes mellitus (DM) in adult zebrafish results in an impairment of tissue regeneration as monitored by caudal fin regeneration. Following streptozocin withdrawal, a recovery phase occurs to reestablish euglycemia, via pancreatic beta‐cell regeneration. However, DM‐associated impaired fin regeneration continues indefinitely in the metabolic memory (MM) state, allowing for subsequent molecular analysis of the underlying mechanisms of MM. This study focuses on elucidating the molecular basis that explains the DM‐associated impaired fin regeneration and why it persists into the MM state with the aim of better understanding MM. Using a combination of microarray analysis and bioinformatics approaches, our study found that of the 14,900 transcripts analyzed, aberrant expression of 71 genes relating to tissue developmental and regeneration processes were identified in DM fish and the altered expression of these 71 genes persisted in MM fish. Key regulatory genes of major development and signal transduction pathways were identified among this group of 71. The aberrant expression of key regulatory genes in the DM state that persist into the MM state provides a plausible explanation on how hyperglycemia induced impaired fin regeneration in the adult zebrafish DM/MM model.
The role of skin substitutes in the management of chronic cutaneous wounds
Authors: Greaves Nicholas S. , Iqbal Syed A. , Baguneid Mohamed , Bayat Ardeshir
Published: February 2013

Chronic wounds, including diabetic and venous ulcers, represent disruption of normal healing processes resulting in a pathological state of nonhealing cutaneous inflammation. They place an increasingly significant economic burden on healthcare providers as their prevalence is rising in keeping with an aging population. Current treatment modalities are slow acting and resource intensive. Bioengineered skin substitutes from autogenic, allogenic, or xenogenic sources have emerged as a new and alternative therapeutic option. A range of such products is licensed for clinical use, which differ in terms of structure and cellular content. Placed directly onto a prepared wound bed, skin substitutes may stimulate or accelerate healing by promoting revascularization, cellular migration, and repopulation of wound fields through provision of an appropriate scaffold material to facilitate these processes. Products containing fetal or autologous cells also benefit from early release of bioactive molecules including growth factors and cytokines. To date, limited numbers of randomized controlled trials studying skin substitutes have been published but evidence from case series and case‐control studies is encouraging. This review discusses chronic wound biology, the influence that skin substitutes can exert on this environment, the products currently available, and examines the evidence for their use in chronic wound management.
Active Structural-Acoustic Control of Laminated Composite Truncated Conical Shells Using Smart Damping Treatment
Authors: Shah P. H. , Ray M. C.
Published: February 2013

This article deals with the active structural-acoustic control of composite truncated circular conical shells using active constrained layer damping (ACLD) treatment. The constraining layer of the ACLD treatment is made of vertically/obliquely reinforced 1–3 piezoelectric composite (PZC) material. A finite element model of smart laminated truncated conical shells backed by the acoustic cavity and integrated with the patches of such ACLD treatment has been developed to demonstrate the performance of these patches for active structural-acoustic control of symmetric and antisymmetric cross-ply and antisymmetric angle-ply truncated conical laminated shells. Both velocity and pressure rate feedback control laws have been implemented to activate the patches. Particular emphasis has also been placed on investigating the effect of variation of piezoelectric fiber orientation angle in the constraining layer on the performance of the patches.
Coupled Flight-Dynamic and Low-Order Aeroelastic Model for a Slender Launch Vehicle
Authors: Sinclair Andrew J. , Flowers George T.
Published: February 2013

This paper presents a method to develop a low-order aeroelastic model that qualitatively captures some of the phenomena experienced by launch vehicles, suitable for use in preliminary controller design. Equations of motion for the two-dimensional dynamics are derived by treating the vehicle as a beam with a gimbaled nozzle attached at the aft end. The flexible-body dynamics are kinematically described using a modal representation. An aerodynamic model focuses on flow separations at diameter transitions in the transonic regime that can lead to lengthwise variations in the applied aerodynamic force. Additionally, convective effects are modeled that lead to time lag in the aerodynamic forces. The equations of motion are tenth order when neglecting convective effects and twelfth order when including convective effects. The model demonstrates some of the possible coupling that occurs between rigid-body, flexible-body, and aerodynamic states. For representative parameter values, the aeroelastic coupling can destabilize the flexible-body motion. The resulting linearized model is not fully controllable, however, is stabilizable.
Linearized Frequencies and Damping in Composite Laminated Beams Subject to Buckling
Authors: Chortis Dimitris I. , Varelis Dimitris S. , Saravanos Dimitris A.
Published: February 2013

This paper considers the damped small-amplitude free-vibration of composite laminated strips subject to large in-plane forces and rotations. A theoretical framework is formulated for the prediction of the nonlinear damping of composite laminates subject to large Green–Lagrange axial strains and assuming a Kelvin viscoelastic solid. An extended beam finite element is developed capable of providing the nonlinear stiffness and damping matrices of the system. The linearized damped free-vibration equations associated with the deflected strip shape in the pre- and postbuckling region are presented. Numerical results quantify the strong geometric nonlinear effect of compressive in-plane loads on the modal damping and frequencies of composite strips. Measurements of the modal damping of a cross-ply glass/epoxy beam subject to buckling were also conducted and correlate well with the finite element predictions.
Molecular beam epitaxial growth of high-reflectivity and broad-bandwidth ZnTe/GaSb distributed Bragg reflectors
Authors: Fan Jin , Liu Xinyu , Ouyang Lu , Pimpinella Richard E. , Dobrowolska Margaret , Furdyna Jacek K. , Smith David J. , Zhang Yong-Hang
Published: February 2013

This paper reports the molecular beam epitaxial growth and characterization of high-reflectivity and broad-bandwidth distributed Bragg reflectors (DBRs) made of ZnTe/GaSb quarter-wavelength (λ/4) layers for optoelectronic applications in the midwave infrared spectral range (2–5 μm). A series of ZnTe/GaSb DBRs has been successfully grown on GaSb (001) substrates using molecular beam epitaxy (MBE). During the MBE growth, a temperature ramp was applied to the initial growth of GaSb layers on ZnTe to protect the ZnTe underneath from damage due to thermal evaporation. Post-growth characterization using high-resolution x-ray diffraction, atomic force microscopy, and transmission electron microscopy reveals smooth surface morphology, low defect density, and coherent interfaces. Reflectance spectroscopy results show that a DBR sample of seven λ/4 pairs has a peak reflectance as high as 99.0% centered at 2.56 μm with a bandwidth of 517 nm.
A new method to retrieve phase information for equiangular fan beam differential phase contrast computed tomography
Authors: Wu Zhao , Gao Kun , Wang Zhili , Ge Xin , Chen Jian , Wang Dajiang , Pan Zhiyun , Zhang Kai , Zhu Peiping , Wu Ziyu
Published: February 2013

Purpose:

Sample radiation damage is one of the main drawbacks limiting applications of the x‐ray phase‐contrast imaging method. Recently, for x‐ray grating‐based phase contrast imaging, the reverse projection (RP) method has been proposed by Zhu et al. [Proc. Natl. Acad. Sci. U.S.A. 107, – (2010) 10.1073/pnas.1003198107]. Compared to the conventional phase stepping technique, the RP method allows a strong reduction of the exposure time and minimization of the errors induced by mechanical vibrations. However, so far, it has only been considered for parallel beam illumination, typical of a synchrotron radiation source. In this paper, a generalization of the RP method from parallel beam geometry to fan beam geometry was presented and discussed.

Methods:

Within parallel beam geometry, the RP method utilizes the conjugate characteristic between reverse projection images. Nevertheless, this characteristic is not directly satisfied for fan beam geometry. In this study, a phantom composed of known materials was constructed and the projection images of the phantom were calculated in a fan beam geometry. By considering single ray, the conjugate images of the projection images were derived from the projection dataset. After that, using the modified RP method the authors retrieved phase and absorption information from paired images.

Results:

Extracted phase and absorption information of the phantom were in good agreement with theoretical values. Additionally, the slice reconstruction was performed and the results turned out to be in the authors’ expectation.

Conclusions:

Theoretical calculations and numerical simulations confirm both feasibility and validity of the RP method under fan beam illumination. Because this method is simple, fast, and releases a relatively low dose, the authors believe that this research is very useful for the x‐ray phase contrast imaging applications in clinical diagnosis, bioresearch, and industrial nondestructive testing.
Classical and semiclassical description of initial distributions of kaon capture by atomic hydrogen and deuterium
Authors: Riahi Rashid , Raeisi Morteza
Published: February 2013

The moderation and capture of negative kaons by atomic hydrogen and deuterium were investigated by the classical trajectory Monte–Carlo (CTMC) and the semiclassical fermion molecular dynamics (FMD) methods. The dependence of ionization and capture cross sections on initial kaon energy was also studied. The initial populations of kaonic atom levels were calculated. The n distributions of kaonic atoms peaked close to the orbital giving optimum overlap with the displaced electronic orbital. The angular momentum distributions, l, are found to be approximately statistical but cut off at large l smaller than lmax = n − 1 in large n. The results are compared with the adiabatic ionization, diabatic states, and Born approximation methods. The FMD results were found to be in better agreement with quantum mechanical calculations than the ones from CTMC. The kaon kinetic energy spectrum prior to capture was calculated, which reveals that capture occurs at small collision energies up to the ionization energy. Also, the calculations show that kaonic hydrogen (deuterium) atoms have kinetic energies below 0.3 a.u. (0.15 a.u.) after formation.
Fluorescence quenching of 6BDTC by aniline in different solvents
Authors: Nagaraja D. , Melavanki R.M. , Patil N.R.
Published: February 2013

Quenching mechanisms of coumarin derivative 6-bromo-3-[1-(4,5-dicarbomethoxy-1,2,3-triazoloacetyl)]coumarin (6BDTC) were carried out in different solvents using the steady-state method to understand the role of diffusion in the quenching mechanism. The solute was excited by UV radiation of wavelength 360 nm. Various quenching parameters like frequency of encounter, kd; probability of quenching per encounter, p; and quenching rate parameter, kq, were experimentally determined for all solvents. Activation energies of quenching, Ea, were also determined by using the literature values of activation energy of diffusion, Ed. It was found that the values of Ea were less than Ed in all solvents indicating that the quenching reactions are more significantly influenced by material diffusion.
INTERACTIONS OF PEDESTRIANS INTERLACED IN T-SHAPED STRUCTURE USING A MODIFIED MULTI-FIELD CELLULAR AUTOMATON
Authors: FU ZHIJIAN , YANG LIZHONG , RAO PING , ZHANG TAOLIN
Published: February 2013

Little work has been done before in the study of separating pedestrian flow interlaced. Under open boundaries, the interaction of separating pedestrian flow interlaced in a T-shaped structure was simulated, using a modified multi-field cellular automaton updating synchronously. The free-jammed phase transition diagram of pedestrian flow and principles of the pedestrian interference were obtained. The movement of pedestrians is free flow in the low entrance density. While it is a complete jammed flow with the entrance density increasing to a certain level and little difference existing between the left moving probability and the right moving probability. Thus, the dominant factor influencing pedestrian flow is the interference of opposite pedestrian flows due to changing movement directions. And it is changing to an incomplete jammed flow with this difference increasing. Thus, the dominant factor is changing to the interference of the coincident pedestrian flow and the limitation of the bottleneck.
MODELS OF PARTICLE PHYSICS FROM TYPE IIB STRING THEORY AND F-THEORY: A REVIEW
Authors: MAHARANA ANSHUMAN , PALTI ERAN
Published: February 2013

We review particle physics model building in type IIB string theory and F-theory. This is a region in the landscape where in principle many of the key ingredients required for a realistic model of particle physics can be combined successfully. We begin by reviewing moduli stabilization within this framework and its implications for supersymmetry breaking. We then review model building tools and developments in the weakly coupled type IIB limit, for both local D3-branes at singularities and global models of intersecting D7-branes. Much of recent model building work has been in the strongly coupled regime of F-theory due to the presence of exceptional symmetries which allow for the construction of phenomenologically appealing Grand Unified Theories. We review both local and global F-theory model building starting from the fundamental concepts and tools regarding how the gauge group, matter sector and operators arise, and ranging to detailed phenomenological properties explored in the literature.
A NEW SCHEDULING PROTOCOL DESIGN BASED ON DEFICIT WEIGHTED ROUND ROBIN FOR QoS SUPPORT IN IP NETWORKS
Authors: OUNI RIDHA , BHAR JAMILA , TORKI KHOLDOUN
Published: February 2013

We present a study of the effects of active queue management (AQM) on the average queue size in routers. In this work, three prominent AQM schemes are considered: packet classification, checking service level agreements (SLA) and queue scheduling. This paper presents several adaptive resource sharing models that use a revenue criterion to allocate bandwidth in an optimal way. The models ensure QoS requirements of data flows and, at the same time, maximize the total revenue by adjusting parameters of the underlying schedulers. Deficit round robin (DRR) and deficit weighted round robin (DWRR) scheduling techniques have shown their ability in providing fair and weighted sharing of network resources for network devices. However, they are unable to use the total allocated network bandwidth even in burst traffic. In this paper, we propose a negative-deficit weighted round robin (N-DWRR) technique as a new packet scheduling discipline to improve the bandwidth utilization rate without increasing the total latency. A fully hardware packet scheduler has been implemented and verified as part of an intellectual property core. This is motivated by the fact that the design and analysis of hardware/software architectures for such techniques requires new models and methods, which do not fall under the domain of traditional embedded-systems design.
HIGH QUALITY FACTOR L-BAND ACTIVE INDUCTOR-BASED BAND-PASS FILTERS
Authors: STORNELLI V. , PANTOLI L. , LEUZZI G.
Published: February 2013

In this letter, a tunable high-Q active inductor with high dynamic range is presented. The equivalent inductance and resistance values can be tunable in a wide frequency range by changing the compensating network components values; outside the operating frequency band, the equivalent resistance increases, improving signal rejection for band-pass filter applications. A second-order active band-pass filter with a central frequency of 2100 MHz using the high-Q active inductance has been fabricated and tested.
POSSIBILISTIC SAFETY ASSESSMENT OF HYBRID UNCERTAIN SYSTEMS
Authors: SAM PALASH CHANDRA , CHAKRABORTY SUBRATA
Published: February 2013

The safety evaluations of structures are usually performed by assuming uncertain 18 input parameters either as probabilistic or possibilistic in nature. Safety evaluations of structural systems characterized by some of the input parameters as possibilistic and others that are sufficient enough to model as probabilistic are unsuitable and restricted to gross assumption at early stages of modeling. The present paper deals with the safety analysis of such a hybrid uncertain system. Relying on the fundamental concept of entropy-based transformation; the feasibility of reliability analysis of a hybrid uncertain system in a possibilistic format is demonstrated in the present study. This will enable the designers to model the structural parameter uncertainty probabilistically as well possibilistically depending on the nature and quality of the input data. The bounds on the probability of failure based on the evidence theory are also computed to study the consistency of the possibility of failure results obtained by the transformation-based algorithm. A numerical example illustrates the capability of the proposed possibilistic approach of safety evaluation of hybrid uncertain system.
GEOMETRIC PREQUANTIZATION OF THE DUAL A LIE ALGEBRA
Authors: HEDREA CIPRIAN , GOLET IOAN , NEGREA ROMEO
Published: February 2013

We present here a range of considerations relating to the problem of Dirac for a quantifiable manifold (M, ω) to the dual a Lie algebra with a Poisson structure that is a Lie–Poisson structure minus.
Epigenetics: Setting Up Lifetime Production of Beef Cows by Managing Nutrition
Authors: Funston R.N. , Summers A.F.
Published: February 2013

Longevity of cattle is correlated to reproductive success. Many studies in different species report the influence of maternal nutrition on progeny performance, health, and reproduction. Maternal nutrient status can cause epigenetic alterations to the genome of the developing fetus, which potentially can impact future generations. This review discusses fetal programming mechanisms as well as maternal nutrition’s impact on placental development and progeny heifer performance and reproduction owing to nutrient restriction, age, or production status. Furthermore, we discuss how early neonatal nutrient intake and type can influence future productivity in the beef and dairy cow. Understanding how these factors influence progeny performance will enable cattlemen to produce replacement females better adapted to their environment through maternal nutrient regulation by stimulating fetal programming.
Accelerating Improvement of Livestock with Genomic Selection
Authors: Meuwissen Theo , Hayes Ben , Goddard Mike
Published: February 2013

Three recent breakthroughs have resulted in the current widespread use of DNA information: the genomic selection (GS) methodology, which is a form of marker-assisted selection on a genome-wide scale, and the discovery of large numbers of single-nucleotide markers and cost effective methods to genotype them. GS estimates the effect of thousands of DNA markers simultaneously. Nonlinear estimation methods yield higher accuracy, especially for traits with major genes. The marker effects are estimated in a genotyped and phenotyped training population and are used for the estimation of breeding values of selection candidates by combining their genotypes with the estimated marker effects. The benefits of GS are greatest when selection is for traits that are not themselves recorded on the selection candidates before they can be selected. In the future, genome sequence data may replace SNP genotypes as markers. This could increase GS accuracy because the causative mutations should be included in the data.
A Global Optimizing Policy for Decaying Items with Ramp-Type Demand Rate under Two-Level Trade Credit Financing Taking Account of Preservation Technology
Authors: Singh S. R. , Sharma Swati
Published: February 2013

An inventory system for deteriorating items, with ramp-type demand rate, under two-level trade credit policy taking account of preservation technology is considered. The objective of this study is to develop a deteriorating inventory policy when the supplier provides to the retailer a permissible delay in payments, and during this credit period, the retailer accumulates the revenue and earns interest on that revenue; also the retailer invests on the preservation technology to reduce the rate of product deterioration. Shortages are allowed and partially backlogged. Sufficient conditions of the existence and uniqueness of the optimal replenishment policy are provided, and an algorithm, for its determination, is proposed. Numerical examples draw attention to the obtained results, and the sensitivity analysis of the optimal solution with respect to leading parameters of the system is carried out.
Finite Iterative Algorithm for Solving a Complex of Conjugate and Transpose Matrix Equation
Authors: Ramadan Mohamed A. , El-Danaf Talaat S. , Bayoumi Ahmed M. E.
Published: February 2013

We consider an iterative algorithm for solving a complex matrix equation with conjugate and transpose of two unknowns of the form: A1VB1+C1WD1+A2V¯B2+C2W¯D2+A3VHB3+C3WHD3+A4VTB4 +

C4WTD4=E. With the iterative algorithm, the existence of a solution of this matrix equation can be determined automatically. When this matrix equation is consistent, for any initial matrices V1, W1 the solutions can be obtained by iterative algorithm within finite iterative steps in the absence of round-off errors. Some lemmas and theorems are stated and proved where the iterative solutions are obtained. A numerical example is given to illustrate the effectiveness of the proposed method and to support the theoretical results of this paper.