bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomechanics of the gastrointestinal tract
Authors: GREGERSEN H. , KASSAB G.
Published: November 2010

Abstract As the function of the gastrointestinal tract is to a large degree mechanical, it has become increasingly popular to acquire distensibility data in motility research based on various parameters. Hence it is important to know on which geometrical and mechanical assumptions the various parameters are based. Currently, compliance and tone derived from pressure‐volume curves are by far the most often used parameters. However, pressure‐volume relations obtained in tubular organs must be carefully interpreted as they provide no direct measure of luminal cross‐sectional area and other variables useful in plane stress and strain analysis. Thus, erroneous conclusions concerning tissue distensibility may be deduced. Other parameters, such as wall tension, stress and strain, give more useful information about mechanical behaviour. Distensibility data procure significance in fluid mechanics and in the study of tone, peristaltic reflexes, and mechanoreceptor kinematics. Such data are needed for the determination of the interaction between stimulus, electrical responses in neurons and the mechanical behaviour of the gut. Furthermore, from a clinical perspective, investigation of visco‐elastic properties is important because GI diseases are associated with growth and remodelling. For example, prestenotic dilatation, increased collagen synthesis, dysmotility and altered distensibility are common features of obstructive diseases. The purpose of this review is to discuss the physiological and clinical importance of acquiring biomechanical data, distensibility parameters and interpretation of these results and their associated errors. We will also discuss some aspects of the relationship between morphology, growth and biomechanics. Finally, we will outline a number of techniques to study the mechanical properties of the GI tract.
Nitrergic inhibition of migrating myoelectric complex in the rat is mediated by vasoactive intestinal peptide
Authors: HELLSTRÖM P. M. , LJUNG T.
Published: November 2010

AbstractThe role of vasoactive intestinal peptide (VIP) for the action of nitric oxide (NO) as a nonadrenergic noncholinergic inhibitory mediator was investigated regarding effects on migrating myoelectric complex (MMC) in rat. Animals were supplied with implanted bipolar electrodes at 5, 15 and 25 cm distal to pylorus for electromyography of small intestine. First, basal recordings with saline were followed by intravenous infusions of glyceryl trinitrate or VIP at different infusion rates to achieve dose‐response relationships. Second, effects of different doses of the nitric oxide synthase inhibitor, Nω‐nitro‐L‐arginine (L‐NNA) were studied. Third, the action of L‐NNA (1 mg kg−1) on the effect of VIP (500 pmol kg−1min−1), and of the VIP receptor antagonist (4‐Cl‐D‐Phe6, Leu17), VIP (45 nmol 20 min−1), on the action of glyceryl trinitrate (44 nmol kg−1min−1) was investigated. Glyceryl trinitrate prolonged the MMC cycle length from 16.3 ± 1.3 to 44.9 ± 8.0 min (P < 0.001), while VIP completely disrupted the MMC for the whole infusion period (P < 0.05). Higher doses of either compound induced quiescence. L‐NNA shortened MMC cycle length from 14.7 ± 1.2 to 8.6 ± 1.4 min (P < 0.05), increased its propagation velocity from 2.0 ± 0.4 to 18.3 ± 8.4 cm min−1(P < 0.01) and increased calculated length from 6.3 ± 1.0 to 55.4 ± 18.4 cm (P < 0.01). Pretreatment with (4‐Cl‐D‐Phe6,Leu17)VIP blocked the inhibitory action of glyceryl trinitrate and preserved MMC pattern (P < 0.05). In contrast, L‐NNA had no effect on the inhibition of MMC caused by VIP. Our results indicate that inhibition of MMC is related to production of NO, which may mediate its actions through VIP.
Evaluation of early events in the creation of amyenteric opossum model of achalasia
Authors: SINGARAM C. , SWEET M. A. , GAUMNITZ E. A. , BASS P. , SNIPES R. L.
Published: November 2010

AbstractBenzyldimethyltetradecylammonium chloride (BAC) has previously been used to create amyenteric rat jejunal models. Fifteen opossums (D. virginiana) were injected with 10–15 mL 4 mM BAC or saline in the distal oesophagus and along with controls underwent oesophagoscopy, manometry and barium oesophagrams. Atropine and sodium nitroprusside were studied in six of the BAC‐treated and five controls using oesophageal manometry. Histologically several neuronal markers, B‐NADPH‐diaphorase and acetylcholine esterase histochemical staining were used. NADPH‐diaphorase activity was assayed at the lower oesophageal sphincter (LOS) and 3 and 5 cm above LOS in both groups. Oesophagoscopy of the treated animals showed no mucosal inflammation, or strictures. Manometrically, LOS pressures were significantly higher in the BAC‐treated group (25.7 ± 8.6 mmHg) when compared to controls (8.7 ± 1.8 mmHg). The oesophageal contraction amplitudes were similar in both groups. While sodium nitroprusside (SNP) significantly reduced the LOS pressure, atropine did not alter the resting LOS pressure in the BAC‐treated animals. Histologically at the LOS the treated group showed: (i) absence of myenteric neurons, in contrast to prominent NADPH‐diaphorase and other neuron and peptide markers in the control and (ii) ***increàse in the number of nerve bundles that were not positive for AchE. No differences were seen in the oesophageal body between the groups. The NADPH‐diaphorase assay showed a significant decrease of activity in the BAC‐treated LOS, but no differences in the oesophageal body compared to controls. Several of these radiologic, manometric and histological observations resemble features of achalasia and the mechanism of the tonic pressure increase at this early time point appears to be due to a non‐cholinergic mechanism.
Mitogenic Response and Cytokine Production Induced by Cramoll 1,4 Lectin in Splenocytes of Inoculated Mice
Authors: de Melo C. M. L. , Melo H. , Correia M. T. S. , Coelho L. C. B. B. , da Silva M. B. , Pereira V. R. A.
Published: November 2010

Cramoll 1,4 is a lectin with specific glucose/mannose binding, which is extracted from seeds ofCratylia mollisMart. Many assays have shown the cytokine expression activity and anti‐inflammatory profile of this lectin. The aim of this study was to evaluate the immunostimulatory response,in vitro, of splenocytes in mice previously inoculated,in vivo, withC. mollis(Cramoll 1,4) andCanavalia ensiformis(Con A) lectins. Results demonstrated higher proliferation indexes induced by Cramoll 1,4 than Con A lectin in relation to all experimental groups. Cramoll 1,4 and Con A also induced high levels of IL‐2, IL‐6, IFN‐γ and nitric oxide production. Moreover, Cramoll 1,4 did not induce apoptosis and stimulated a significant number of cells in the S phase of the cell cycle. Results showed that Cramoll 1,4 lectin induces proliferative response and suggested that this lectin can be used as a mitogenic agent in immunostimulatory assays.
Short‐Term Metabolism of Radioactive Kinetin during Lettuce Seed Germination
Authors: MIERNYK J. A. , BLAYDES D. F.
Published: November 2010

Exogenously applied 8‐14C‐kinetin is rapidly taken up by seeds of lettuce (Lactuca sativa L. cv. Grand Rapids). Radioactive metabolites were extracted and purified by solvent fractionation, column and paper chromatography. The primary metabolite was identified as the 9‐riboside‐5′‐monophosphate. As germination proceeds, some kinetin is released from this bound storage form, giving a maximum level of free kinetin at 12 hours after imbibition. After this time the concentration of ribotide increases while the concentration of free base decreases. Other metabolites are the 9‐riboside, AMP and IMP.

It is suggested that a required amount of free base cytokinin is necessary by 12 hours after imbibition. This concentration of free cytokinin may act as a physiological trigger for later events during germination.
Ethylene Production and Mycelium Growth of the Tulip Strain of Fusarium oxysporum as Influenced by Shaking of and Oxygen Supply to the Culture Medium
Authors: SWART ANNIE , KAMERBEEK G. A.
Published: November 2010

The fungus Fusarium oxysporum Schlecht f. sp. tulipae Apt. can produce ethylene abundantly in vitro when grown in Pratt's liquid medium with glucose as the only organic substrate. This production starts after a lag phase of about 4 days, and peak production occurs when mycelium weight has reached its maximum value. For several days the rate of production is more or less linearly dependent on pO2. The total production is also dependent on the oxygen concentration, but pure oxygen inhibits the total production by about 50% as compared with 21% oxygen. The high production in shake cultures, as compared with the low production in stagnant cultures, is probably the result of a better oxygen supply in the culture medium. The mycelium weight proved not to be a valid referential basis for the production of ethylene.
Characterization of Cyclic Nucleotide Phosphodiesterase Activity in Sunflower Callus
Authors: JUNKER S. , VERBEEK‐WYNDAELE R. , TRUELSEN T. A.
Published: November 2010

A membrane‐bound and a soluble cyclic nucleotide phosphodiesterase from sunflower callus has been examined. Kinetic studies showed Km‐values in the range of 2.5‐5.0 mM with cyclic adenosine 3′,5′‐monophosphate (3′, 5′‐cAMP) as the substrate. The soluble cyclic nucleotide phosphodiesterase was characterized further: Optimal activity was at pH 6.5‐7.0 and at 40°C. The enzyme did not require divalent metal ions for maximal activity. It was inhibited by Cu2+ and slightly activated by Fe3+. Sodium fluoride, imidazole and theophylline did not affect the activity, but caffeine was slightly inhibitory. Its activity was strongly inhibited by ATP, AMP and Pi. The enzyme hydrolysed 3′,5′‐cAMP, 2′,3′‐cAMP and 3′,5′‐cGMP, while N6, O2′‐dibutyryl cyclic AMP (dBcAMP) was left unattacked. The soluble enzyme activity was influenced neither by callus age nor by plant growth substances added in vivo or in vitro.
Glutamate Dehydrogenase Activity in Lemna perpusilla 6746: The Effects of Sucrose, Glucose and Fructose Addition to Growth Media
Authors: DUKE STANLEY H. , KOUKKARI WILLARD L.
Published: November 2010

Lemna perpusilla Torr, strain 6746 clones were maintained under conditions of continuous illumination with various concentrations of sucrose, glucose or fructose added to the growth, medium. After two weeks of growth, plants were harvested and either assayed for total glutamate dehydrogenase activity or fractionated into one chloroplast‐rich and one mitochondria‐rich preparation and then assayed for glutamate dehydrogenase activity. In all assays for glutamate dehydrogenase it was necessary to add bovine serum albumin to the extraction medium in order to obtain sufficient enzyme activity for accurate and reproducible results. The presence of sucrose in the growth medium reduced glutamate dehydrogenase activity in all studies. When samples containing intact organelles were assayed, sucrose inhibition of activity appeared to occur primarily in the chloroplast fraction. Glucose, on the other hand, increased glutamate dehydrogenase activity in the chloroplast‐rich fractions. Upon freeze‐thawing differences between the various treatments were less obvious. The results from these studies indicate possible differences in sugar uptake and/or utilization in Lemna perpusilla.
Epidemiological, clinical and prognostic indices in IgA nephropathy
Authors: D'AMICO Giuseppe
Published: November 2010

Summary: IgAN is the commonest primary glomerulonephritis in all parts of the world; the different incidence reported in different geographical areas is mainly due to different biopsy policies, even though genetic factors, still unclarified, may be acting. Progression to ESRF occurs in IgAN at a variable rate (average renal survival at 10 years is 80–87%), and many studies, reviewed in this paper, have sought to identify clinical and histological features which are predictive of the outcome. A functional impairment at presentation and a severe proteinuria are the most powerful clinical indicators of unfavourable prognosis, while both glomerular and interstitial sclerosis are the most reliable histological indicators. The fact that these prognostic indicators are not always reliable in predicting the outcome for a single patient, probably due to the pathophysiology of the progressive damage in this disease, is stressed.
Three‐year randomized controlled trial of dipyridamole and low‐dose warfarin in patients with IgA nephropathy and renal impairment
Authors: LEE GSL , CHOONG HL , CHIANG GSC , WOO KT
Published: November 2010

Summary: Activation of platelets and the coagulation pathway are factors which may contribute to the progression of renal disease in IgA nephropathy (IgAN). Of 21 patients with IgAN and serum creatinines between 1.6 and 3.0 mg/dL, 10 were assigned to treatment with dipyridamole and low‐dose warfarin (keeping the thrombotest between 30 and 50%) and 11 to no treatment in a prospective randomized 3‐year study. At entry into the trial, patients in the treatment group were younger (35 ± 6 years vs 42 ± 9 years) and had worse histological scores for tubular atrophy (1.7 ± 0.7 vs 1.1 ± 0.5) and arteriolar hyperplasia (1.4 ± 0.7 vs 0.7 ± 0.8) than those in the non‐treatment group. There were no differences in serum creatinine values, creatinine clearances, urinary protein excretions, serum albumins or urinary erythrocyte counts. At the end of the trial, patients on treatment did not experience a significant increase in serum creatinine values (1.9 ± 0.3 mg/dL to 2.5 ± 1.2) or reduction in creatinine clearances (52 ± 20mL/min to 52 ± 27). Untreated patients, however, experienced a significant rise in serum creatinine values (2.1 ± 0.5 mg/dL to 3.3 ± 1.1, P < 0.01) and a fall in creatinine clearances (51 ± 26 mL/min to 31 ± 22, P = 0.06). There was no significant change in the proteinuria in either group (treatment group: 1.2 ± 1.2 g/day to 1.3 ± 1.1, non‐treatment group: 1.9 ± 1.4 to 1.5 ± 1.1) and there was also no change in serum albumins and urinary erythrocyte counts. Four untreated and one treated patient developed end‐stage renal failure during the course of the trial. This study suggests that treatment of patients with IgAN and renal impairment with dipyridamole and low‐dose warfarin retards the deterioration of renal function, as measured by the serum creatinine and creatinine clearance.
Team process in community‐based participatory research on maternity care in the Dominican Republic
Authors: Foster Jennifer , Chiang Fidela , Hillard Rebecca C , Hall Priscilla , Heath Annemarie
Published: November 2010

FOSTER J, CHIANG F, HILLARD RC, HALL P and HEATH A. Nursing Inquiry 2010; 17: 309–316 Team process in community‐based participatory research on maternity care in the Dominican Republic

A cross‐cultural team consisting of US trained academic midwife researchers, Dominican nurses, and Dominican community leaders have partnered in this international nursing and midwifery community‐based participatory research (CBPR) project in the Dominican Republic to understand the community experience with publicly funded maternity services. The purpose of the study was to understand community perceptions of maternity services. This article highlights the activities that the research team carried out during each phase of the research process, and how they established team identity, team trust, and team efficacy. This research has created a platform for new avenues for health providers and community to partner to improve maternal‐newborn care. Community‐based participatory research is one way forward to address the past and present inequities constitutive of global health disparities.
Yoga for chronic pain management: a qualitative exploration
Authors: Tul Yvonne , Unruh Anita , Dick Bruce D.
Published: November 2010

Scand J Caring Sci; 2011; 25; 435–443
 
Yoga for chronic pain management: a qualitative exploration

Objective:  To explore patients’ perceptions of their pain while participating in a weekly yoga program.

Methods:  A consecutive convenience sample was recruited from a Multidisciplinary Pain Centre. Seven adult patients (six women), agreed to participate in an 8‐week Hatha yoga program, including weekly group sessions and at‐home practice. Data were gathered from participant observation and in‐depth interviews. Interviews explored the experience of practicing yoga and its relationship to the participant’s pain experience. An inductive analysis of the interviews explored emergent themes from participants’ descriptions of their experience.

Results:  Analyses identified three themes: renewed awareness of the body; transformed relationship with the body in pain; and acceptance.

Discussion:  Participants’ data suggested that they reframed what it meant to live with chronic pain. Some participants reported that the sensory aspects of pain did not change but that pain became less bothersome. They were better able to control the degree to which pain interfered with their daily life. Other participants reported less frequent or less intense pain episodes because they could recognize body signals and adjust themselves to alleviate painful sensations. The findings suggest that patients who benefit from yoga may do so in part because yoga enables changes in cognitions and behaviours towards pain.
Occurrence of Incisional Complications and Associated Risk Factors Using a Right Ventral Paramedian Celiotomy Incision in 159 Horses
Authors: Anderson Stacy L. , Vacek John R. , MacHarg Margaret A. , Holtkamp Derald J.
Published: November 2010

Objective:To evaluate the occurrence of, and variables associated with, incisional complications after right ventral paramedian celiotomy in horses.

Study Design:Case series.

Animals:Horses (n=159).

Methods:Occurrence of incisional complications after right ventral paramedian celiotomy was determined in 159 horses (161 celiotomies) that survived at least 30 days after surgery at a private equine hospital (2003–2007). Follow‐up information for 121 horses was obtained ≥90 days after surgery. Univariate analysis and multivariate logistic regression was performed to evaluate variables associated with incisional complications after celiotomy.

Results:Of 161 celiotomies, ≥1 incisional complications occurred in 27 (16.8%) during hospitalization and/or after discharge, including: drainage (15.5%), skin dehiscence (3.7%), noticeable cutaneous scarring (1.9%), and herniation (0.6%). Variables significantly associated with incisional complications after multivariate analysis included: Quarter horse‐type breed (odds ratio [OR]: 3.9, 95% confidence interval [95% CI]: 1.3–11.7); use of an abdominal bandage (OR: 9.5, 95% CI: 2.9–30.8); and >4 postoperative febrile (>38.3°C) days (OR: 12.9, 95% CI: 2.8–58.2).

Conclusions:Overall occurrence of incisional complications after right paramedian ventral celiotomy compared favorably to those reported for ventral median celiotomies. Several variables were associated with, but not necessarily predictive for, the occurrence of incision complications.
A Preliminary Study on the Effect of Wounding on Transforming Growth Factor‐β1 and Cartilage Oligomeric Matrix Protein Concentrations in the Skin of Horses
Authors: Dart Andrew J. , Dart Christina M. , Dudhia Jay , Perkins Nigel , Canfield Paul , Smith Roger K. W.
Published: November 2010

Objective: To evaluate whether wound type or site influence the production of cartilage oligomeric matrix protein (COMP) and transforming growth factor β1 (TGF‐β1), and determine if there is a correlation between TGF‐β1and COMP during healing.

Study Design: Experimental.

Animals: Standardbred horses (n=6), 4–8 years old.

Methods: Six, standardized, full‐thickness skin wounds (open, straight, and elliptical) were surgically created on the neck (n=3) and metacarpus (3) on each horse. Wounds were randomly allocated to site and side. Tissue samples were collected before creating wounds and on days 7, 14, and 42. COMP concentration (μg/g dry weight of tissue) was determined using a standard competitive ELISA and TGF‐β1 (ng/g dry weight of tissue) was determined using a commercially available sandwich ELISA.

Results: COMP concentrations were higher in intact skin on the neck compared with the metacarpus (P=.02). There was no difference in COMP and TGF‐β1 concentrations between the different wound types or sites during healing. There was no correlation between TGF‐β1 and COMP during healing.

Conclusions: Within the limitations of the study design, production of COMP during healing of skin wounds does not appear to be influenced by wound type or anatomic site, nor does it appear to be correlated with TGF‐β1 concentrations.
Why Are CEOs Rarely Fired? Evidence from Structural Estimation
Authors: TAYLOR LUCIAN A.
Published: November 2010

I evaluate the forced CEO turnover rate and quantify effects on shareholder value by estimating a dynamic model. The model features learning about CEO ability and costly turnover. To fit the observed forced turnover rate, the model needs the average board of directors to behave as if replacing the CEO costs shareholders at least $200 million. This cost mainly reflects CEO entrenchment rather than a real cost to shareholders. The model predicts that shareholder value would rise 3% if we eliminated this perceived turnover cost, all else equal. The model also helps explain the relation between CEO firings, tenure, and profitability.
The Net Benefits to Leverage
Authors: KORTEWEG ARTHUR
Published: November 2010

I estimate the market's valuation of the net benefits to leverage using panel data from 1994 to 2004, identified from market values and betas of a company's debt and equity. The median firm captures net benefits of up to 5.5% of firm value. Small and profitable firms have high optimal leverage ratios, as predicted by theory, but in contrast to existing empirical evidence. Companies are on average slightly underlevered relative to the optimal leverage ratio at refinancing. This result is mainly due to zero leverage firms. I also look at implications for financial policy.
Leverage Choice and Credit Spreads when Managers Risk Shift
Authors: CARLSON MURRAY , LAZRAK ALI
Published: November 2010

We model the debt and asset risk choice of a manager with performance‐insensitive pay (cash) and performance‐sensitive pay (stock) to theoretically link compensation structure, leverage, and credit spreads. The model predicts that optimal leverage trades off the tax benefit of debt against the utility cost of ex‐post asset substitution and that credit spreads are increasing in the ratio of cash‐to‐stock. Using a large cross‐section of U.S.‐based corporate credit default swaps (CDS) covering 2001 to 2006, we find a positive association between cash‐to‐stock and CDS rates, and between cash‐to‐stock and leverage ratios.
Lucky CEOs and Lucky Directors
Authors: BEBCHUK LUCIAN A. , GRINSTEIN YANIV , PEYER URS
Published: November 2010

We study the relation between opportunistic timing of option grants and corporate governance failures, focusing on “lucky” grants awarded at the lowest price of the grant month. Option grant practices were designed to provide lucky grants not only to executives but also to independent directors. Lucky grants to both CEOs and directors were the product of deliberate choices, not of firms’ routines, and were timed to make them more profitable. Lucky grants are associated with higher CEO compensation from other sources, no majority of independent directors, no outside blockholder on the compensation committee, and a long‐serving CEO.
The changing landscape of Indian agriculture
Authors: Gulati Ashok , Ganguly Kavery
Published: November 2010

In tracking the revolutionary changes in the Indian agricultural sector, it is quite clear that technology, institutions, and markets have had a very important role to play. Of course, the public sector played a pivotal and catalytic role when India ushered in the Green Revolution in late 1960s and early 1970s. The public sector imported new seeds, organized their distribution and demonstration, and provided price and market support, all “not‐for‐profit.” The cooperative sector, supported and facilitated by the government, again with the spirit of “not‐for‐profit,” helped bring in the White Revolution in milk through Operation Flood in 1970s and 1980s. This spirit is now being gradually replaced by “for‐profit” objective driven by the private sector, as is demonstrated in the revolutionary changes brought about by the introduction of Bacillus thuringiensis technology in the cotton sector during 2002–2007. On top of this, the corporate sector is also changing the complexion of the Indian agrisystem through notable changes in organized food processing and retailing. This change in spirit from “not‐for‐profit” to “for‐profit” in the growth process of Indian agriculture has significant implications for the concept of CISS, i.e., competitiveness, inclusiveness, sustainability, and scalability, which needs to be studied carefully and in detail. Accordingly, this article traces some of these dynamic changes and their likely implications.
Conditioning trends shaping the agricultural and rural landscape in Africa
Authors: Adesina Akinwumi A.
Published: November 2010

African countries continue to face deepening food crises that have been accentuated by the global food, energy, and financial crises. This situation is part of a long‐term structural problem: decades of under‐investments in agricultural sector and poor policies of support for smallholder farmers who form the bulk of the farming population. The inability of these farmers to achieve a supply response when commodity prices were high and market access was less of a problem suggests that there are multiple sets of binding constraints that continue to limit the potential of agricultural growth to reduce food security and poverty on the continent. This article reviews some of the historical trends that have hampered the performance of the agriculture sector. In addition, it reviews the impacts of more positive trends that could stimulate agricultural growth in Africa that could change the African agricultural landscape. The article however warns that there are more recent global developments and some continental challenges that could prevent or slow agricultural growth. These include the global financial crisis, public sector investments, inequities in global agricultural development policies, rush for agricultural lands by foreign investors, domestic commercial financing markets, climate change, and emerging carbon markets. The article argues that while opportunities for accelerated growth exists for African agriculture, new sets of policy instruments will be needed to support smallholder farmers to access new agricultural technologies, finance, reduce impacts of climate change, and adopt sustainable land use practices that can allow them to benefit from emerging global carbon markets.
Analyzing collective action
Authors: Ostrom Elinor
Published: November 2010

Collective‐action problems pervade all societies as well as ecological systems used by humans. Substantial evidence has accrued during the last several decades that human actors are able to solve some (but definitely not all) collective‐action problems on their own without external rules and enforcement imposed from the outside. In this article, I review some of the structural variables that have been found to affect the likelihood of collective action. Then, I address the need to base future work on collective action on a more general theory of human behavior than has been used to model collective action over the last five decades. In the last section, I discuss how structural variables affect the core relationships of reputation, trust, and reciprocity as these affect levels of cooperation.
Applying economic sociology to understand the meaning of “Quality” in food markets
Authors: Allaire Gilles
Published: November 2010

This article reviews the concept of the “market” and questions the standard view of the “market” developed by orthodox economic theory. The article highlights how Economic Sociology and Convention Theory is more useful in understanding markets and appreciating markets as social constructs, which are governed by institutions and social orders. This adjustment in the analytical framework to study markets and especially food markets, is useful in unpacking the various dimensions of “quality” in food products and illustrating that “quality” is an institution that is shaped by society and by culture.
Cell signaling
Authors: Iqbal Jameel , Zaidi Mone , Avadhani Narayan G.
Published: November 2010

This review explores advances in our understanding of dynamicism in cellular signaling. Areas highlighted include the role of stochasticity in producing diversity in analogous signaling circumstances; population desynchronization's effect in masking newly appreciated repetitive bursts in protein phosphorylation and messenger RNA production; double‐positive feedback interactions and their ability to synchronize multiple signal transduction pathways; scaffolding proteins control over signaling feedback; and frequency‐responsive transcriptional regulation as an example of dynamicism in signaling.
Measurement of Singlet‐Oxygen In Vivo: Progress and Pitfalls
Authors: Kanofsky Jeffrey R.
Published: November 2010

This article is a highlight of the paper by Jarvi et al. in this issue of Photochemistry and Photobiology as well as a brief overview of the state of the field of singlet‐oxygen (1O2) detection in vivo. The in vivo detection of 1O2 using its characteristic 1270 nm phosphorescence is technically challenging. Nevertheless, substantial progress has been made in this area. Major advances have included the commercial development of photomultiplier tubes sensitive to 1270 nm light, techniques for spatially resolving the location of 1O2 at a subcellular level and more complex mathematical models for interpreting the kinetics of 1O2 emission from living cells. It is now recognized that oxygen consumption, photosensitizer bleaching, oxidation of biological molecules and diffusion of 1O2 can significantly change the kinetics of 1O2 emission from living cells.
A Comparison of Preservice Elementary Teachers' Beliefs About Mathematics and Teaching Mathematics: 1968 and 1998
Authors: Seaman Carol E. , Szydlik Jennifer Earles , Szydlik Stephen D. , Beam John E.
Published: November 2010

The study replicates Collier's (1972) work. It focuses on the beliefs of a large sample of elementary education students at four stages of teacher preparation, about both the nature of and the teaching of mathematics. The instrument measures what Collier termed a “formal‐informal” dimension of belief. The data suggest that initially the 1998 students held significantly more informal (constructivist) beliefs than did their 1968 counterparts. In both years, students moved toward more informal beliefs during the course of their programs, with the most significant changes occurring in their beliefs about how mathematics should be taught. However, apparent contradictions in belief structures were observed both at the start and at the end of their programs. Thus, it appears that though many students acquired new, more informal beliefs during the course of their programs, they did not develop robust, consistent philosophies of mathematics education.
Effect of aluminium oxide particle sandblasting on the artificial tooth–resin bond
Authors: Consani Rafael Leonardo Xediek , Richter Marina Martorano , Mesquita Marcelo Ferraz , Sinhoreti Mario Alexandre Coelho , Guiraldo Ricardo Danil
Published: November 2010

Aim:  The influence of tooth ridge‐lap surface sandblasting with aluminium oxide particles was evaluated on the adhesion of artificial teeth to acrylic resins.

Methods:  Specimens were made with the acrylic resin adhered to teeth (BioCler GII), according to an unmodified surface, glossy surface sandblasted with 50‐μm particles and conventional (Classico) or microwaved (Onda Cryl) resin, and a glossy surface sandblasted with 100‐μm particles and Classico or Onda Cryl resin. The shear bond test was performed in an Instron machine using a 500‐N load cell and cross‐speed of 1 mm/min.

Results:  The analysis of variance revealed significant difference in the tooth–resin shear bond strength for resin, surface treatment, and interaction. For conventional resin, control, 50‐, and 100‐μm particles showed statistically‐different values; for microwaved resin, the control showed less statistical difference when compared to 50‐ and 100‐μm particle treatments; for between resins, only the 100‐μm particle treatment showed statistically‐different values, with lower values for the microwaved resin. Mixed failures (cohesive in the resin and adhesive) were predominantly observed in all groups. Mixed (cohesive in the tooth and adhesive) or adhesive failures were not observed.

Conclusions:  Sandblasting with different aluminium oxide particle sizes produced different effects on the shear strength values of the tooth–resin bond.
Enamelin/ameloblastin gene polymorphisms in autosomal amelogenesis imperfecta among Syrian families
Authors: Dashash Mayssoon , Bazrafshani Mohamed Riza , Poulton Kay , Jaber Saaed , Naeem Emad , Blinkhorn Anthony Stevenson
Published: November 2010

Aim:  This study was undertaken to investigate whether a single G deletion within a series of seven G residues (codon 196) at the exon 9–intron 9 boundary of the enamelin gene ENAM and a tri‐nucleotide deletion at codon 180 in exon 7 (GGA vs deletion) of ameloblastin gene AMBN could have a role in autosomal amelogenesis imperfecta among affected Syrian families.

Methods:  A new technique – size‐dependent, deletion screening – was developed to detect nucleotide deletion in ENAM and AMBN genes. Twelve Syrian families with autosomal‐dominant or ‐recessive amelogenesis imperfecta were included.

Results:  A homozygous/heterozygous mutation in the ENAM gene (152/152, 152/153) was identified in affected members of three families with autosomal‐dominant amelogenesis imperfecta and one family with autosomal‐recessive amelogenesis imperfecta. A heterozygous mutation (222/225) in the AMBN gene was identified. However, no disease causing mutations was found. The present findings provide useful information for the implication of ENAM gene polymorphism in autosomal‐dominant/‐recessive amelogenesis imperfecta.

Conclusion:  Further investigations are required to identify other genes responsible for the various clinical phenotypes.
Faster O2 uptake kinetics in canine skeletal muscle in situ after acute creatine kinase inhibition
Authors: Grassi Bruno , Rossiter Harry B. , Hogan Michael C. , Howlett Richard A. , Harris James E. , Goodwin Matthew L. , Dobson John L. , Gladden L. Bruce
Published: November 2010

Non‐technical summary

The ability to sustain skeletal muscle contractions is dependent on the conversion of chemical to mechanical energy – a process fueled by adenosine triphosphate (ATP). The link between two of the major mechanisms for ATP provision, phosphocreatine (PCr) breakdown and oxidative phosphorylation, was investigated in canine muscle. Infusion of a drug to prevent PCr breakdown (via inhibition of the enzyme creatine kinase; CK) caused (among other effects) a faster adjustment of energy provision from oxidation upon the onset of contractions. Thus, in mammalian skeletal muscle the CK enzyme slows the signal responsible for the activation of oxidative phosphorylation. Sudden increases in the demands for energy at the onset of exercise are met by PCr breakdown, but this process is functionally related, presumably through the levels of some of its metabolites, to the regulation of oxidative phosphorylation, the most important pathway for ATP resynthesis.
Reciprocal Ia inhibition contributes to motoneuronal hyperpolarisation during the inactive phase of locomotion and scratching in the cat
Authors: Geertsen Svend S. , Stecina Katinka , Meehan Claire F. , Nielsen Jens B. , Hultborn Hans
Published: November 2010

Non‐technical summary

During a movement, the contraction of a given muscle group is often coordinated with the simultaneous relaxation of its antagonist muscles. The neural basis of this antagonist relaxation has been investigated in both animal and human experiments for decades and it is believed that activation of the Ia inhibitory interneurones by central motor programmes plays a major role in this relaxation of antagonist muscles. The alternating movements during locomotion would seem to especially require reciprocal actions, but recent studies have raised significant questions about the role of this inhibition. We found that inhibition evoked by these inhibitory interneurones is largest when their target motoneurones are inactive – even in the absence of supraspinal influence. The results of this work provide new evidence for the role of the Ia inhibitory interneurones during rhythmic motor activity. This supports the classical view of reciprocal inhibition as a basis for antagonist relaxation.
On the fabrication of three-dimensional silicon-on-insulator based optical phased array for agile and large angle laser beam steering systems
Authors: Hosseini Amir , Kwong David , Zhang Yang , Chandorkar Saurabh A. , Crnogorac Filip , Carlson Andrew , Fallah Babak , Bank Seth , Tutuc Emanuel , Rogers John , Pease R. Fabian W. , Chen Ray T.
Published: November 2010

In this article, the authors present and discuss the fabrication of three-dimensional (3D) optical phased array (OPA) devices for large angle, two-dimensional optical beam steering. Fabrication of a single layer (one-dimensional) OPA prototype for one-dimensional beam steering on silicon nanomembrane is presented. The authors present different approaches, such as nanoimprint lithography, optical lithography, and self-aligned patterning of multibonded silicon-on-insulator wafers, for the realization of 3D OPA devices in particular and 3D photonic circuits in general. At the end, the authors discuss the challenges and potential solutions.
Akt and Autophagy Cooperate to Promote Survival of Drug-Resistant Glioma
Authors: Fan Qi-Wen , Cheng Christine , Hackett Chris , Feldman Morri , Houseman Benjamin T. , Nicolaides Theodore , Haas-Kogan Daphne , James C. David , Oakes Scott A. , Debnath Jayanta , Shokat Kevan M. , Weiss William A.
Published: November 2010

Combined inhibition of PI3K, mTOR, and autophagy promotes glioma cell death.
Hippo Checks Regeneration
Authors: VanHook Annalisa M.
Published: November 2010

The Hippo signaling target Yap is dispensable for homeostasis of the intestinal epithelium but is required for regeneration.
Calmodulin and Brain Development
Authors: Ray L. Bryan
Published: November 2010

Calmodulin appears to function in control of synaptic properties that vary in the front- and hindbrain.
Tonic Inhibition
Authors: Stern Peter R.
Published: November 2010

The neurotransmitter GABA is tonically released from cells through an anion channel with an unusually large pore.
Grooming and Growing with Microglia
Authors: Antony Joseph Mathew
Published: November 2010

Microglia modulate neurobehavior.
Science Signaling
Podcast: 9 November 2010
Authors: Fields R. Douglas , VanHook Annalisa M.
Published: November 2010

A nonvesicular, nonsynaptic form of communication between axons and neighboring cells may play a role under normal conditions and in disease.
Visualizing Calcium Signaling in Astrocytes
Authors: Fields R. Douglas
Published: November 2010

Astrocyte signaling is apparent in movies of rat brain astrocytes cultured with fluorescent calcium indicator dyes.
Changes in Cell Wall Synthesis and Ultrastructure during Paradoxical Growth Effect of Caspofungin on Four Different
Candida
Species
Authors: Bizerra Fernando C. , Melo Analy S. A. , Katchburian Eduardo , Freymüller Edna , Straus Anita H. , Takahashi Hélio K. , Colombo Arnaldo L.
Published: November 2010

Paradoxical growth (PG) has been described for echinocandins and is characterized by cell growth at drug concentrations above the MIC. In this study, two isolates each of
Candida albicans
,
C. tropicalis
,
C. orthopsilosis
, and
C. parapsilosis
, all of which displaying PG in response to caspofungin, were subjected to MIC, minimal fungicidal concentration (MFC), and time-kill curve assays to evaluate the levels of PG. Cell wall components and ultrastructural modifications of the PG cells were also investigated. The results showed that when cell growth and survival were evaluated by MFC or time-kill curve assays, high concentrations of caspofungin did not show fungicidal activity against PG cells. Furthermore, for
C. parapsilosis
and
C. orthopsilosis
, time-kill curves were more discriminatory than MFCs in detecting the PG effect. The four different
Candida
species studied demonstrated similar alterations in cell wall components and ultrastructure associated with PG. In PG cells, β-1,3-glucan content decreased from 2.7- to 7.8-fold, whereas chitin content increased from 4.0- to 6.6-fold. An electron microscopy study of the PG cells revealed morphological alterations, clumping of cells, enlarged cells, the absence of filamentation, abnormal septa, and accumulation of chitin in the cell wall. Also, PG cells basically exhibited a single dark high-density layer in the cell wall, indicating the loss of the β-1,3-glucan layer. Our results present novel details about the ultrastructural alterations that occur in
C. albicans
,
C. parapsilosis
,
C. orthopsilosis
, and
C. tropicalis
during PG and show that chitin is the major component of the cell walls of PG cells. Stimulation of chitin synthesis may represent a rescue mechanism against caspofungin activity.
Metallo-β-Lactamase Production by
Pseudomonas otitidis
: a Species-Related Trait
Authors: Thaller Maria Cristina , Borgianni Luisa , Di Lallo Gustavo , Chong Yunsop , Lee Kyungwon , Dajcs Joseph , Stroman David , Rossolini Gian Maria
Published: November 2010

Susceptibility to several β-lactams and β-lactamase production was investigated in a collection of 20 strains of
Pseudomonas otitidis
, a new
Pseudomonas
species that has been recently recognized in association with otic infections in humans. All strains appeared to be susceptible to piperacillin, cefotaxime, ceftazidime, and aztreonam, while resistance or decreased susceptibility to carbapenems was occasionally observed. All strains were found to express metallo-β-lactamase (MBL) activity and to carry a new subclass B3 MBL gene, named
bla
POM
, that appeared to be highly conserved in this species.
P. otitidis
, therefore, is the first example of a pathogenic
Pseudomonas
species endowed with a resident MBL. The POM-1 protein from
P. otitidis
type strain MCC10330 exhibits the closest similarity (60 to 64%) to the L1 MBL of
Stenotrophomonas maltophilia
. Expression in
Escherichia coli
and
Pseudomonas aeruginosa
revealed that, similar to L1 and other subclass B3 MBLs, POM-1 confers decreased susceptibility or resistance to carbapenems, penicillins, and cephalosporins but not to aztreonam. Expression of the POM MBL in
P. otitidis
is apparently constitutive and, in most strains, does not confer a carbapenem-resistant phenotype. However, a strong inoculum size effect was observed for carbapenem MICs, and carbapenem-resistant mutants could be readily selected upon exposure to imipenem, suggesting that carbapenem-based regimens should be considered with caution for
P. otitidis
infections.
Cyclopentadienyl ruthenium complexes with tricarbollide ligands
Authors: Perekalin Dmitry S. , Trifonova Evgeniya A. , Glukhov Ivan V. , Holub Josef , Kudinov Alexander R.
Published: November 2010

Reaction of the tricarbollide anion [7,8,9-C3B8H11]– (1a) with the naphthalene complex [CpRu(C10H8)]+ under visible light irradiation in CH2Cl2 gives the 12-vertex closo-ruthenacarborane 1-Cp-1,2,3,5-RuC3B8H11 (2; 87% yield). This complex was also obtained by reaction of 1a with CpRu(cod)Cl (97%). Upon heating at 80 °C in toluene 2 rearranges into isomer 1-Cp-1,2,4,10-RuC3B8H11 (3; 63%). Irradiation of 1a with [CpRu(C10H8)]+ in acetone gives the 11-vertex closo-1-Cp-1,2,3,4-RuC3B7H10 (4; 32%). The latter was also prepared by reaction of 1a with [CpRu(MeCN)3]+ (59%). Compound 2 slowly undergoes cage contraction in acetone giving 4. Irradiation of 1a with [Cp*Ru(C10H8)]+ affords the isomeric 12-vertex closo-ruthenacarboranes 1-Cp*-1,2,3,5-RuC3B8H11 and 1-Cp*-1,2,4,10-RuC3B8H11 (2.2:1 ratio; 56%). Reaction of the amino-substituted tricarbollide anion [7-tBuNH-7,8,9-C3B8H10]– with [(C5R5)Ru(C10H8)]+ (R = H, Me) selectively gives 12-vertex closo-ruthenacarboranes 1-(C5R5)-12-tBuNH-1,2,4,12-RuC3B8H10 (ca. 50%). The structures of 2 and 4 were confirmed by X-ray diffraction.
Oxidation pathways of natural dye hematoxylin in aqueous solution
Authors: Sokolová Romana , Degano Ilaria , Hromadová Magdaléna , Bulíčková Jana , Gál Miroslav , Valášek Michal
Published: November 2010

The oxidation mechanism of hematoxylin was studied in phosphate buffers and 0.1 M KCl by cyclic voltammetry and UV-Vis spectroscopy under deaerated conditions. The redox potential of hematoxylin in buffered solution strongly depends on pH. A two electron oxidation is preceded by deprotonation. The homogeneous rate of deprotonation process of hematoxylin in 0.1 M phosphate buffer is kd = (2.5 ± 0.1) × 104 s–1. The cyclic voltammetry under unbuffered conditions shows the distribution of various dissociation forms of hematoxylin. The dissociation constants pK1 = 4.7 ± 0.2 and pK2 = 9.6 ± 0.1 were determined using UV-Vis spectroscopy. The final oxidation product was identified by gas chromatography with mass spectrometry detection as hemathein. The distribution of oxidation products differs under buffered and unbuffered conditions. The dye degradation in natural unbuffered environment yields hemathein and hydroxyhematoxylin, which is absent in buffered solution.
Derivation of new reference tables for human heart weights in light of increasing body mass index
Authors: Gaitskell Kezia , Perera Rafael , Soilleux Elizabeth J
Published: November 2010

As body weights and body mass indices have increased over time, we questioned the validity of correlating heart weight with body weight and whether tables from previous decades remain relevant. We investigated this by collecting details of heart weight, body weight, height, gender and age from 384 autopsy cases with no obvious heart or lung disease. Heart weights, body weights and heights showed a normal distribution for both genders. Heart weight correlated slightly better with body surface area than body weight and we present new reference charts derived from these data. The correlation between heart weight and body weight has changed little, despite increases in body weight and body mass index. As life expectancy is increasing, we investigated the effect of age on heart weight and demonstrated a small increase in heart weight relative to body surface area for both genders, in contrast to a previous study.
Establishing a ‘physician's spiritual well-being scale’ and testing its reliability and validity
Authors: Fang C K , Li P Y , Lai M L , Lin M H , Bridge D T , Chen H W
Published: November 2010

The purpose of this study was to develop a Physician's Spiritual Well-Being Scale (PSpWBS). The significance of a physician's spiritual well-being was explored through in-depth interviews with and qualitative data collection from focus groups. Based on the results of qualitative analysis and related literature, the PSpWBS consisting of 25 questions was established. Reliability and validity tests were performed on 177 subjects. Four domains of the PSpWBS were devised: physician's characteristics; medical practice challenges; response to changes; and overall well-being. The explainable total variance was 65.65%. Cronbach α was 0.864 when the internal consistency of the whole scale was calculated. Factor analysis showed that the internal consistency Cronbach α value for each factor was between 0.625 and 0.794 and the split-half reliability was 0.865. The scale has satisfactory reliability and validity and could serve as the basis for assessment of the spiritual well-being of a physician.