bluuebunny/crossref_metadata_2025 huggingface dataset:
Microwave Dielectric Properties of Ba2Ca1−xSrxWO6Double Perovskites
Authors: Zhou Yuanyuan , Meng Siqin , Wu Hongchao , Yue Zhenxing
Published: March 2011

Ba2Ca1−xSrxWO6 (x=0–1) microwave dielectric ceramics have been prepared using the two‐step solid‐state reaction method. The substitution of Sr2+ for Sr2+ can effectively lower the densification temperature of the ceramics from 1500° to 1200°C. Single‐phase ceramics with double perovskite structures were obtained, and structural transitions occurred in Ba2Ca1−xSrxWO6 via the phase sequence: cubic→rhombohedral→monoclinic with an increase of x. The microwave dielectric properties of the Ba2Ca1−xSrxWO6 ceramics can be effectively tuned by tailoring x. The dielectric constant (ɛr) remains almost unvaried, the quality factor (Q × f) decreases monotonically, and the temperature coefficient of resonant frequency (τf) changes in sign with the increase of x. A good combination of the microwave dielectric properties was obtained for Ba2Ca0.975Sr0.025WO6 sintered at 1250°C: ɛr=23.9, Q × f=80 200 GHz, and τf=+18 ppm/°C.
Annealing Effects on Semitransparent and Ferromagnetic ZnFe2O4 Nanostructured Films by Sol–Gel
Authors: Li Gang , Zhu Xuebin , Song Wenhai , Yang Zhaorong , Dai Jianming , Sun Yuping , Fu Yankun
Published: March 2011

ZnFe2O4 films have been prepared using a sol–gel route. The influences of annealing temperature as well as annealing atmosphere on the structural, morphological, magnetic, and optical properties were investigated. The TEM and SEM images show that ZnFe2O4 films are polycrystalline in nature and homogeneous with densely packed grains. ZnFe2O4 films exhibit ferromagnetic behavior at 300 K and high transparency (≥80%) above the absorption band edge. With decreasing annealing temperature and annealing oxygen partial pressure, the saturated magnetism at 300 K is improved and the optical band gap is decreased. The reasons are discussed, and the results show that semitransparent ZnFe2O4 films with room‐ temperature ferromagnetism can be successfully prepared using a sol–gel method.
Hydrostatic Pressure Dependence of Dielectric, Elastic, and Piezoelectric Properties of Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 Ceramic
Authors: Gao Junjie , Xu Zhuo , Zhang Chonghui , Li Fei , Wei Xiaoyong , Yao Xi
Published: March 2011

The effect of hydrostatic pressure on piezoelectric materials is a crucial factor for underwater device design. In this work, the dielectric, elastic, and piezoelectric properties of Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 [PMNT (67/33)] ceramics were investigated under pressure from 0.1 to 455 MPa. The dielectric permittivity and losses were found to increase under hydrostatic pressure due to enhanced domain wall motion. With increasing hydrostatic pressure, the mechanical losses drastically increased, which can be attributed to the increase of both domain wall motion and the friction between pressure‐transmitting fluid and piezoelectric vibrators. In addition, piezoelectric coefficients (d33, d31) and electromechanical coupling factors (k33, k31) were found to decrease with increasing pressure, owing to the pressure‐induced depolarization for PMNT ceramics.
Chromosomal variability of human mesenchymal stem cells cultured under hypoxic conditions
Authors: Ueyama Hanae , Horibe Tomohisa , Hinotsu Shiro , Tanaka Tomoaki , Inoue Takeomi , Urushihara Hisashi , Kitagawa Akira , Kawakami Koji
Published: March 2011

Bone marrow derived human mesenchymal stem cells (hMSCs) have attracted great interest from both bench and clinical researchers because of their pluripotency and ease of expansion ex vivo. However, these cells do finally reach a senescent stage and lose their multipotent potential. Proliferation of these cells is limited up to the time of their senescence, which limits their supply, and they may accumulate chromosomal changes through ex vivo culturing. The safe, rapid expansion of hMSCs is critical for their clinical application. Chromosomal aberration is known as one of the hallmarks of human cancer, and therefore it is important to understand the chromosomal stability and variability of ex vivo expanded hMSCs before they are used widely in clinical applications. In this study, we examined the effects of culturing under ambient (20%) or physiologic (5%) O2 concentrations on the rate of cell proliferation and on the spontaneous transformation of hMSCs in primary culture and after expansion, because it has been reported that culturing under hypoxic conditions accelerates the propagation of hMSCs. Bone marrow samples were collected from 40 patients involved in clinical research. We found that hypoxic conditions promote cell proliferation more favourably than normoxic conditions. Chromosomal aberrations, including structural instability or aneuploidy, were detected in significantly earlier passages under hypoxic conditions than under normoxic culture conditions, suggesting that amplification of hMSCs in a low‐oxygen environment facilitated chromosomal instability. Furthermore, smoothed hazard‐function modelling of chromosomal aberrations showed increased hazard after the fourth passage under both sets of culture conditions, and showed a tendency to increase the detection rate of primary karyotypic abnormalities among donors aged 60 years and over. In conclusion, we propose that the continuous monitoring of hMSCs will be required before they are used in therapeutic applications in the clinic, especially when cells are cultured under hypoxic conditions.
Apoptosis related protein‐1 triggers melanoma cell death via interaction with the juxtamembrane region of p75 neurotrophin receptor
Authors: Selimovic Denis , Sprenger Achim , Hannig Matthias , Haïkel Youssef , Hassan Mohamed
Published: March 2011

Although chemotherapeutic drugs could theoretically target all metastatic sites, current treatments do not provide complementary therapeutics. Therefore, the development of an alternative approach replacing the traditional therapy is urgently needed. To assess the killing efficiency of the functionally identified apoptosis‐related protein (APR)‐1 in melanoma cells, we established a system for the regulated expression of APR‐1. The induction of APR‐1 expression caused apoptosis of melanoma cells via the interaction with the juxtamembrane region of p75 neurotrophin receptor (p75NTR), and possible also via the competition with tumour necrosis factor receptor‐associated factor‐6 (TRAF6) and the catalytic receptor of neurotrophin (Trk) for the same p75NTR interacting site. The accumulation of APR‐1 in melanoma cells may block the physical association of p75NRT with TRAF6 and/or Trk, leading to the disruption of both NF‐κB and extracellular signal‐regulated kinase (ERK) pathways. Also, accumulation of APR‐1 protein enhanced the activity of both c‐Jun‐N‐terminal kinase (JNK) and p38 pathways. However, the analysis of APR‐1‐modulated pathways demonstrated the involvement of apoptosis‐regulating kinase 1‐JNK/p38 pathway in the induction of Bax expression leading to both mitochondrial dysregulation [as demonstrated by the loss of mitochondrial membrane potential, the release of both cytochrome c and apoptosis‐inducing factor into cytoplasm, and cleavage of caspase‐9, caspase‐3 and poly (ADP‐ribose) polymerase (PARP)] and endoplasmic reticulum stress as demonstrated by the increase of intracellular Ca2+ release. Thus, besides the analysis of its pro‐apoptotic function, our data provide insight into the molecular mechanism of APR‐1‐induced apoptosis of melanoma cells.
Progesterone enhances vascular endothelial cell migration via activation of focal adhesion kinase
Authors: Zheng Shuhui , Huang Jinghe , Zhou Kewen , Xiang Qiuling , Zhang Yaxing , Tan Zhi , Simoncini Tommaso , Fu Xiaodong , Wang Tinghuai
Published: March 2011

The mechanisms of progesterone on endothelial cell motility are poorly investigated. Previously we showed that progesterone stimulated endothelial cell migration via the activation of actin‐binding protein moesin, leading to actin cytoskeleton remodelling and the formation of cell membrane structures required for cell movement. In this study, we investigated the effects of progesterone on the formation of focal adhesion complexes, which provide anchoring sites for cell movement. In cultured human umbilical endothelial cells, progesterone enhanced focal adhesion kinase (FAK) phosphorylation at Tyr397 in a dose‐ and time‐dependent manner. Several signalling inhibitors interfered with progesterone‐induced FAK activation, including progesterone receptor (PR) antagonist ORG 31710, specific c‐Src kinase inhibitor PP2, phosphatidylinosital‐3 kinase (PI3K) inhibitor wortmannin as well as ρ‐associated kinase (ROCK‐2) inhibitor Y27632. It suggested that PR, c‐Src, PI3K and ROCK‐2 are implicated in this action. In line with this, we found that progesterone rapidly promoted c‐Src/PI3K/Akt activity, which activated the small GTPase RhoA/ρ‐associated kinase (ROCK‐2) complex, resulting in FAK phosphorylation. In the presence of progesterone, endothelial cells displayed enhanced horizontal migration, which was reversed by small interfering RNAs abrogating FAK expression. In conclusion, progesterone promotes endothelial cell movement via the rapid regulation of FAK. These findings provide new information on the biological actions of progesterone on human endothelial cells that are relevant for vascular function.
High‐molecular weight Aβ oligomers and protofibrils are the predominant Aβ species in the native soluble protein fraction of the AD brain
Authors: Upadhaya Ajeet Rijal , Lungrin Irina , Yamaguchi Haruyasu , Fändrich Marcus , Thal Dietmar Rudolf
Published: March 2011

Alzheimer’s disease (AD) is characterized by the aggregation and deposition of amyloid β protein (Aβ) in the brain. Soluble Aβ oligomers are thought to be toxic. To investigate the predominant species of Aβ protein that may play a role in AD pathogenesis, we performed biochemical analysis of AD and control brains. Sucrose buffer‐soluble brain lysates were characterized in native form using blue native (BN)‐PAGE and also in denatured form using SDS‐PAGE followed by Western blot analysis. BN‐PAGE analysis revealed a high‐molecular weight smear (>1000 kD) of Aβ42‐positive material in the AD brain, whereas low‐molecular weight and monomeric Aβ species were not detected. SDS‐PAGE analysis, on the other hand, allowed the detection of prominent Aβ monomer and dimer bands in AD cases but not in controls. Immunoelectron microscopy of immunoprecipitated oligomers and protofibrils/fibrils showed spherical and protofibrillar Aβ‐positive material, thereby confirming the presence of high‐molecular weight Aβ (hiMWAβ) aggregates in the AD brain. In vitro analysis of synthetic Aβ40‐ and Aβ42 preparations revealed Aβ fibrils, protofibrils, and hiMWAβ oligomers that were detectable at the electron microscopic level and after BN‐PAGE. Further, BN‐PAGE analysis exhibited a monomer band and less prominent low‐molecular weight Aβ (loMWAβ) oligomers. In contrast, SDS‐PAGE showed large amounts of loMWAβ but no hiMWAβ40 and strikingly reduced levels of hiMWAβ42. These results indicate that hiMWAβ aggregates, particularly Aβ42 species, are most prevalent in the soluble fraction of the AD brain. Thus, soluble hiMWAβ aggregates may play an important role in the pathogenesis of AD either independently or as a reservoir for release of loMWAβ oligomers.
Cerebral correlates of psychotic syndromes in neurodegenerative diseases
Authors: Jellinger Kurt A.
Published: March 2011

Introduction

Old age and Alzheimer’s disease

Lewy body diseases

Psychosis has been recognized as a common feature in neurodegenerative diseases and a core feature of dementia that worsens most clinical courses. It includes hallucinations, delusions including paranoia, aggressive behaviour, apathy and other psychotic phenomena that occur in a wide range of degenerative disorders including Alzheimer’s disease, synucleinopathies (Parkinson’s disease, dementia with Lewy bodies), Huntington’s disease, frontotemporal degenerations, motoneuron and prion diseases. Many of these psychiatric manifestations may be early expressions of cognitive impairment, but often there is a dissociation between psychotic/behavioural symptoms and the rather linear decline in cognitive function, suggesting independent pathophysiological mechanisms. Strictly neuropathological explanations are likely to be insufficient to explain them, and a large group of heterogeneous factors (environmental, neurochemical changes, genetic factors, etc.) may influence their pathogenesis. Clinico‐pathological evaluation of behavioural and psychotic symptoms (PS) in the setting of neurodegenerative and dementing disorders presents a significant challenge for modern neurosciences. Recognition and understanding of these manifestations may lead to the development of more effective preventive and therapeutic options that can serve to delay long‐term progression of these devastating disorders and improve the patients’ quality of life. A better understanding of the pathophysiology and distinctive pathological features underlying the development of PS in neurodegenerative diseases may provide important insights into psychotic processes in general.
Reliability of the vertical magnification factor on panoramic radiographs: clinical implications for posterior mandibular implants
Authors: Vazquez Lydia , Nizam Al Din Yassin , Christoph Belser Urs , Combescure Christophe , Bernard Jean‐Pierre
Published: March 2011

Objectives: Panoramic radiographs allow evaluation of the available bone height for implant treatment planning while imparting a low radiation dose. As panoramic radiography produces image distortion, reference objects are required to determine the exact magnification. This study aims to estimate a panoramic unit's vertical magnification factor (MF) by measuring the length of dental implants used as radiopaque reference objects on postoperative panoramic radiographs. We compared our findings to the vertical MF listed by the panoramic unit manufacturer, and studied the reproducibility and accuracy of our measuring method by analyzing the inter‐ and intraobserver agreements.

Material and methods: Using a digital calliper, we measured the length of 32 implants on 17 postoperative panoramic radiographs taken with a Scanora® unit. The implants were 10mm‐long standard Straumann® implants placed in the posterior segments of mandibles. The MF was calculated by dividing the implant's radiological length by the implant's real length.

Results: The mean calculated vertical MF was 1.27 ± 0.01 (1.245–1.295) and was lower than the manufacturer's MF (1.3). The vertical MF was 1.28 ± 0.01 in the premolar and 1.27 ± 0.01 in the molar regions. There was an excellent intraobserver reliability (0.96 for observer 1; 0.93 for observer 2) and a good interobserver reliability (0.85 at measurement session 1; 0.8 at measurement session 2)

Conclusions: The observed reliability of the MF confirms that a panoramic radiograph can be used for preoperative implant length evaluation in the posterior mandibular segments. MF stability should be verified with other panoramic units. In clinical practice, using the implant length as a reference object on postoperative panoramic radiographs is a simple and effective evaluation method to estimate a panoramic unit's MF.

To cite this article:
 Vazquez L, Nizam Al Din Y, Belser UC, Combescure C, Bernard J‐P. Reliability of the vertical magnification factor on panoramic radiographs: clinical implications for posterior mandibular implants. Clin. Oral Impl. Res. xx, 2011; 000–000. doi: 10.1111/j.1600‐0501.2010.02131.x
Point‐of‐care oral‐based diagnostics
Authors: Hart RW , Mauk MG , Liu C , Qiu X , Thompson JA , Chen D , Malamud D , Abrams WR , Bau HH
Published: March 2011

Oral Diseases (2011) 17, 745–752

Many of the target molecules that reside in blood are also present in oral fluids, albeit at lower concentrations. Oral fluids are, however, relatively easy and safe to collect without the need for specialized equipment and training. Thus, oral fluids provide convenient samples for medical diagnostics. Recent advances in lab‐on‐a‐chip technologies have made minute, fully integrated diagnostic systems practical for an assortment of point‐of‐care tests. Such systems can perform either immunoassays or molecular diagnostics outside centralized laboratories within time periods ranging from minutes to an hour. The article briefly reviews recent advances in devices for point‐of‐care testing with a focus on work that has been carried out by the authors as part of a NIH program.
Three‐dimensional tomographic mapping related to primary stability and structural miniscrew characteristics
Authors: Silvestrini Biavati A , Tecco S , Migliorati M , Festa F , Marzo G , Gherlone E , Tetè S
Published: March 2011

To cite this article:
 Silvestrini Biavati A, Tecco S, Migliorati M, Festa F, Marzo G, Gherlone E, Tetè S:  Three‐dimensional tomographic mapping related to primary stability and structural miniscrew characteristics  Orthod Craniofac Res 2011;14:88–99

Structured Abstract

Authors –  Silvestrini Biavati A, Tecco S, Migliorati M, Festa F, Marzo G, Gherlone E, Tetè S

Objectives –  To evaluate the maxilla, mandible, and cortical plates on computerized tomographic (CT) scans to achieve accurate three‐dimensional bone thickness measurements.

Setting and Sample Population –  We selected the CT scans of 25 subjects (among 102), aged 18–58 years (10 men, 15 women), with nearly complete dentition.

Material and Methods –  We performed interradicular and bucco‐lingual (including cortical plate thickness) measurements in dental areas distal to the canines in both alveolar arches, at three levels (5, 8, and 11 mm) from the alveolar ridge.

Results –  The mean thicknesses of the cortical plates in the maxilla were 1.10 mm buccally and 1.27 mm on the palatal side (p < 0.05). In the mandible, cortical plates were 2.23 mm buccally and 2.02 mm lingually. Mandibular buccal and lingual cortical plates became thicker distally in the second and third molar areas. There was considerable variation in cortical thickness (from 0.25 to 5.50 mm).

Based on interradicular distances, only 13% of measured sites in the maxilla were suitable for miniscrew insertion (≥3.3 mm), but 63% of sites were suitable in the mandible.

Conclusion –  This study showed considerable individual variation in bone thickness. Our data suggested that the palatal/lingual side may provide greater primary stability for miniscrews. The palatal area, between the second upper bicuspid and the first molar, appeared to be the most suitable area for tapered 7‐ to 9‐mm miniscrews, starting at 1.5–2 mm from the alveolar crest.
Copying medical summaries on deceased infants to bereaved parents
Authors: Clarke Paul , Booth David
Published: March 2011

Aim:  When an infant dies following neonatal intensive care, a detailed medical summary about the infant’s life and death is sent to the general practitioner (GP). Our practice is to send an exact copy of this summary to the parents also. We evaluated the opinions of bereaved parents and their GPs on this practice.

Methods:  We carried out a postal questionnaire survey of bereaved parents who had been sent a copy of our medical summary on their deceased infant and their GPs. Parents were asked to rate the summary for its helpfulness, their understanding of it and how distressing it was to receive. We concurrently surveyed via e‐mail all paediatricians in our region to ask whether they routinely copied letters to bereaved parents.

Results:  Only 3 of 32 (9%) paediatricians routinely copied summaries to bereaved parents. Thirteen of 21 (62%) parents responded: all but one found the copied summary very helpful, most did not find it especially distressing and most reported a fair understanding of it despite its detailed medical content. Almost all their GPs supported copying the summaries to parents.

Conclusion:  Most bereaved parents welcome an exact copy of the detailed medical summary that provides a complete record of their baby’s clinical course, brief life and terminal events.
Role of angiotensin‐converting enzyme gene polymorphism in persistent pulmonary hypertension of the newborn
Authors: De Jesus Lilia C , Kazzi S Nadya J , Dahmer Mary K , Chen Xinguang , Quasney Michael W
Published: March 2011

Aim:  To evaluate the association of angiotensin‐converting enzyme (ACE) gene polymorphism with risk/severity of persistent pulmonary hypertension of the newborn (PPHN) among at risk infants.

Methods:  Infants ≥34 weeks with respiratory distress at birth were recruited. PPHN was diagnosed clinically and by cardiac echocardiogram. Control group consisted of infants with respiratory distress who did not develop PPHN. ACE genotyping (DD, II, DI genotypes) and serum ACE levels were determined.

Results:  A total of 120 infants were included (PPHN = 44; control = 76). Frequency of ACE DD genotype was not different between the two groups of infants (25% versus 33%). Among PPHN infants, severity of illness did not differ between genotypes. Mean (SD) serum ACE levels [15 (9) versus 24 (13) versus 29 (14) U/L] were positively associated with the number of D alleles and inversely associated with infants’ gestational age (GA) and level of cardiovascular support.

Conclusion:  Angiotensin‐converting enzyme gene polymorphism did not impact the risk or severity of PPHN among infants ≥34 weeks GA.
Methaemoglobinaemia with G6PD deficiency: rare cause of persistently low saturations in neonates
Authors: Titheradge Hannah , Nolan Katie , Sivakumar Shanmugasundaram , Bandi Srinivas
Published: March 2011

We report a very rare case of methaemoglobinaemia associated with glucose 6 phosphate dehydrogenase (G6PD) deficiency, complicating a respiratory illness in a preterm neonate. This neonate had consistently low saturation readings despite being ventilated at moderately high pressures in 100% oxygen. An arterial blood gas confirmed a high methaemoglobin level and a high pO2, inconsistent with the saturations. In addition, the bilirubin increased to exchange levels and was difficult to control with quadruple phototherapy. A double volume exchange transfusion was performed, which reduced both bilirubin and methaemoglobin. The pulse oximetry then started to correlate well with pO2. G6PD deficiency was confirmed.

Conclusion:  Paediatricians should remember that methaemoglobinaemia is a rare but important cause of persistently low saturations, and exchange transfusion is a reliable treatment for this condition.
Accretion-induced luminosity spreads in young clusters: evidence from stellar rotation
Authors: Littlefair S. P. , Naylor Tim , Mayne N. J. , Saunders Eric , Jeffries R. D
Published: March 2011

We present an analysis of the rotation of young stars in the associations Cepheus OB3b, NGC 2264, 2362 and the Orion Nebula Cluster (ONC). We discover a correlation between rotation rate and position in a colour–magnitude diagram (CMD) such that stars which lie above an empirically determined median pre-main sequence rotate more rapidly than stars which lie below this sequence. The same correlation is seen, with a high degree of statistical significance, in each association studied here. If position within the CMD is interpreted as being due to genuine age spreads within a cluster, then the stars above the median pre-main sequence would be the youngest stars. This would in turn imply that the most rapidly rotating stars in an association are the youngest, and hence those with the largest moments of inertia and highest likelihood of ongoing accretion. Such a result does not fit naturally into the existing picture of angular momentum evolution in young stars, where the stars are braked effectively by their accretion discs until the disc disperses. Instead, we argue that, for a given association of young stars, position within the CMD is not primarily a function of age, but of accretion history. We show that this hypothesis could explain the correlation we observe between rotation rate and position within the CMD.
Non-Gaussian velocity distributions — the effect on virial mass estimates of galaxy groups
Authors: Ribeiro A. L. B. , Lopes P. A. A. , Trevisan M.
Published: March 2011

We present a study of nine galaxy groups with evidence for non-Gaussianity in their velocity distributions out to 4R200. This sample is taken from the 57 groups selected from the 2dF Percolation-Inferred Galaxy Groups (2PIGG) catalogue of galaxy groups. Statistical analysis indicates that the non-Gaussian groups have masses significantly higher than that of the Gaussian groups. We also have found that all non-Gaussian systems seem to be composed of multiple velocity modes. Besides, our results indicate that multimodal groups should be considered as a set of individual units with their own properties. In particular, we have found that the mass distributions of such units are similar to that of the Gaussian groups. Our results reinforce the idea of non-Gaussian systems as complex structures in the phase space, likely corresponding to secondary infall aggregations at a stage before virialization. The understanding of these objects is relevant for cosmological studies using groups and clusters through the mass function evolution.
MODELING THE RHEOLOGICAL PROPERTIES OF CHEDDAR CHEESE WITH DIFFERENT FAT CONTENTS AT VARIOUS TEMPERATURES
Authors: YANG XIN , ROGERS NEAL ROBERT , BERRY TRISTAN KENDRICKS , FOEGEDING EDWARD ALLEN
Published: March 2011

Cheddar cheese consists of a gel phase with imbedded fat particles and can be represented as a particle‐filled gel. The storage modulus (G′) of Cheddar cheese containing different fat contents was fitted to 12 theoretical models for particle‐filled gels. Models that included the G′ of fat particles and their interactions best described cheese G′. The estimated G′ of fat particle (Gf′) was larger than that of gel matrix (Gm′) at 10, 15 and 20C, corresponding to a reinforcing effect of fat on cheese G′. However, Gf′ decreased at a faster rate than Gm′ with increasing temperature, resulting in a weakening effect at 25C. Cheese rheological properties were dominated by the solid fat phase at 10 and 15C and showed no significant change with aging. In contrast, cheese G′ at 20 and 25C decreased after aging cheeses for 12 weeks, corresponding to decreases of Gm′ as a result of changes in the protein network.

PRACTICAL APPLICATIONS

Fat is critical to cheese texture. The rheological properties of cheeses depend on the two phases: fat particles and protein gel matrix. However, limited works have been done to quantitatively evaluate the contributions from the two phases. In this article, the rheological properties of Cheddar cheese containing a range of fat content were fitted to 12 mathematical models for particle‐filled gels. The advantages and limitations of these theoretical models were compared. This study extended the application of the mathematical models in Cheddar cheese, showing a quantitative evaluation on the role of fat in cheese rheology. This provides quantitative information for developing fat substitutes to function as fat particles in cheese texture.
INFLUENCES OF ADDITIONAL GUM CHEWING ON POSTPRANDIAL GASTRIC MOTILITY
Authors: KOMINE YUKO MITO , HATTORI YOSHINORI
Published: March 2011

Insufficient trituration of food may increase the functional burden on the stomach and delay gastric emptying. However, previous studies have suggested that gastric emptying is not affected by the particle‐size distribution of the swallowed food if masticatory activity is retained. This finding may be related to the prokinetic effect of mastication on gastric motility via the cephalic‐vagal reflex, and increased gastric motility in turn may hasten gastric emptying. Using cutaneous electrogastrography (EGG), we investigated whether nonfeeding gum chewing, termed additional gum chewing (AGC) here, before a meal that is deliberately chewed inadequately increases postprandial gastric motility. Our EGG results showed that the acceleration effect of AGC was rapid and significant, although it lasted less than 30 min. The cumulative gastric motility after AGC was nearly comparable with that after eating with sufficient mastication. Thus, AGC and similar techniques may help improve gastric motility in subjects with reduced masticatory activity.

PRACTICAL APPLICATIONS

Gastric emptying is not affected by the particle‐size distribution of the swallowed food if masticatory activity is retained. Thus, individuals with impaired masticatory efficiency should chew food thoroughly. However, lack of motivation, the habit of eating fast and a soft diet have often been reported to deter individuals from changing their chewing behavior and increasing the number of chewing cycles. The current study revealed that postprandial gastric motility after additional gum chewing (AGC) was almost comparable with that after eating with sufficient mastication, suggesting the practical usefulness of AGC as an alternative to facilitate gastric motility in subjects with reduced masticatory activity.
NUMERICAL SIMULATION OF THE SWALLOWING OF LIQUID BOLUS
Authors: SONOMURA M. , MIZUNUMA H. , NUMAMORI T. , MICHIWAKI H. , NISHINARI K.
Published: March 2011

Thickened liquid foods are given to alleviate swallowing disorder, and their usefulness depends on the flow behavior of the liquid bolus when it is swallowed. In order to optimize the use of the bolus, its swallowing flow was simulated numerically for a pharynx. The rheological model of the bolus liquid was assumed to be a viscous power law model. The movements of the tongue and pharynx were modeled to simulate the swallowing flow. The interaction of the flow of the bolus and the movements of the pharynx were analyzed using a finite element method. In normal swallowing, the viscous liquid reduced the bolus velocity compared with the velocity of the water bolus, but the difference in the velocity because of viscosity was slight between the thickened boluses. With respect to abnormal swallowing, simulations were conducted for two kinds of disorder. (1) When the disorder was caused by dysfunction in the lift up of the throat and retroflexion of the epiglottis, the water bolus was scattered over the epiglottis and was partly aspirated. A thickened bolus of 10 cc was also aspirated from the pyriform sinuses to the larynx. A small bolus of 2 cc remained at the valleculae and then dropped down into the larynx. In contrast, a bolus of 5 cc flowed along the pyriform sinuses and was not aspirated differently from the other cases. (2) When the disorder was caused by early termination of swallowing movements, a part of the bolus remained around the epiglottis, and the return of the epiglottis induced part of the bolus to drop into the larynx. These results suggested that the pattern of the aspiration depended on the swallowing movements, and the viscosity and volume of the bolus.

PRACTICAL APPLICATIONS

Liquid care foods have been developed for use with swallowing disorders, and the particular viscous properties that are optimal for these foods have been studied. However, there are different types of swallowing disorder; hence, providing general guidelines for the properties of liquid care foods is difficult. The object of the study reported herein was to develop a numerical model for the simulation of the swallowing of a liquid bolus, which can be used to aid the effort to produce safe liquid care foods.
THE NEURAL REPRESENTATION OF ORAL TEXTURE INCLUDING FAT TEXTURE
Authors: ROLLS EDMUND T.
Published: March 2011

The brain areas that represent taste also provide a representation of oral texture. Fat texture is represented by neurons independently of viscosity: some neurons respond to fat independently of viscosity, and other neurons encode viscosity. The neurons that respond to fat also respond to silicone and paraffin oil, indicating that the sensing is texture‐ not chemo‐specific. This fat sensing is not related to free fatty acids such as linoleic acid; a few other neurons with responses to free fatty acids typically do not respond to fat in the mouth. Fat texture‐sensitive neurons are found in the primary taste cortex, the secondary taste cortex in the orbitofrontal cortex where the pleasantness of food is represented, and in the amygdala. Different neurons respond to different combinations of texture, taste, oral temperature, and in the orbitofrontal cortex to olfactory and visual properties of food. Complementary human functional neuroimaging studies are described.

PRACTICAL APPLICATIONS

This research has implications for understanding how fat in the mouth is sensed. It therefore has implications for the design of foods that may mimic the mouthfeel of fat, but not its energy content.
Skeletal muscle mass recovery from atrophy in IL‐6 knockout mice
Authors: Washington T. A. , White J. P. , Davis J. M. , Wilson L. B. , Lowe L. L. , Sato S. , Carson J. A.
Published: March 2011

Aim:  Skeletal muscle interleukin‐6 (IL‐6) expression is induced by continuous contraction, overload‐induced hypertrophy and during muscle regeneration. The loss of IL‐6 can alter skeletal muscle’s growth and extracellular matrix remodelling response to overload‐induced hypertrophy. Insulin‐like growth factor‐1 (IGF‐1) gene expression and related signalling through Akt/mTOR is a critical regulator of muscle mass. The significance of IL‐6 expression during the recovery from muscle atrophy is unclear. This study’s purpose was to determine the effect of IL‐6 loss on mouse gastrocnemius (GAS) muscle mass during recovery from hindlimb suspension (HS)‐induced atrophy.

Methods:  Female C57BL/6 [wild type (WT)] and IL‐6 knockout (IL‐6 KO) mice at 10 weeks of age were assigned to control, HS or HS followed by normal cage ambulation groups.

Results:  GAS muscle atrophy was induced by 10 days of HS. HS induced a 20% loss of GAS mass in both WT and IL‐6 KO mice. HS+7 days of recovery restored WT GAS mass to cage‐control values. GAS mass from IL‐6 KO mice did not return to cage‐control values until HS+14 days of recovery. Both IGF‐1 mRNA expression and Akt/mTOR signalling were increased in WT muscle after 1 day of recovery. In IL‐6 KO muscle, IGF‐1 mRNA expression was decreased and Akt/mTOR signalling was not induced after 1 day of recovery. MyoD and myogenin mRNA expression were both induced in WT muscle after 1 day of recovery, but not in IL‐6 KO muscle.

Conclusion:  Muscle IL‐6 expression appears important for the initial growth response during the recovery from disuse.
Parkinson’s disease or Parkinson symptoms following seasonal influenza
Authors: Toovey Stephen , Jick Susan S. , Meier Christoph R.
Published: March 2011

Please cite this paper as: Toovey S et al. (2011) Parkinson’s disease or Parkinson symptoms following seasonal influenza. Influenza and Other Respiratory Viruses 5(5), 328–333.

Background  Influenza may cause neurological sequelae and has been associated with encephalitis lethargica, an entity displaying Parkinson’s disease (PD) signs and symptoms that followed the 1918 influenza pandemic. We studied the association between diagnosed influenza and idiopathic PD or Parkinson symptoms (PS) not followed by a firm PD diagnosis.

Methods  We used the UK‐based General Practice Research Database to perform a case–control analysis. We identified cases who developed an incident diagnosis of PD or PS between 1994 and March 2007, and we matched four controls on age, gender, general practice, calendar time, and history in the database to each case. We calculated odds ratios (OR) with 95% confidence intervals (CI) using conditional logistic regression to assess the relative risk of developing PD or PS in association with previous influenza diagnoses.

Results  We identified 3976 PD cases and 18 336 PS cases. The risk of developing PD was not associated with previous influenza infections. However, PS was associated with recent influenza (last infection 0–29 days: OR 3·03, 95% CI 1·94–4·74; 30–364 days: OR 1·36, 95% CI 1·14–1·63), number of influenza episodes (1 attack: OR 1·20, 95% CI 1·12–1·28; 2 attacks: OR 1·52, 95% CI 1·28–1·81; ≥3 attacks: OR 2·00, 95% CI 1·45–2·75), and severity of preceding influenza infections (≥1 severe attack: OR 1·45, 95% CI 1·25–1·68).

Conclusions  Influenza is associated with PD‐like symptoms such as tremor, particularly in the month after an infection, but not with an increased risk of developing idiopathic PD.
Dynamic Predictive Model for the Growth of Salmonella spp. in Liquid Whole Egg
Authors: Singh Aikansh , Korasapati Nageswara R. , Juneja Vijay K. , Subbiah Jeyamkondan , Froning Glenn , Thippareddi Harshavardhan
Published: March 2011

Abstract:  A dynamic model for the growth of Salmonella spp. in liquid whole egg (LWE) (approximately pH 7.8) under continuously varying temperature was developed. The model was validated using 2 (5 to 15 °C; 600 h and 10 to 40 °C; 52 h) sinusoidal, continuously varying temperature profiles. LWE adjusted to pH 7.8 was inoculated with approximately 2.5–3.0 log CFU/mL of Salmonella spp., and the growth data at several isothermal conditions (5, 7, 10, 15, 20, 25, 30, 35, 37, 39, 41, 43, 45, and 47 °C) was collected. A primary model (Baranyi model) was fitted for each temperature growth data and corresponding maximum growth rates were estimated. Pseudo‐R2 values were greater than 0.97 for primary models. Modified Ratkowsky model was used to fit the secondary model. The pseudo‐R2 and root mean square error were 0.99 and 0.06 log CFU/mL, respectively, for the secondary model. A dynamic model for the prediction of Salmonella spp. growth under varying temperature conditions was developed using 4th‐order Runge–Kutta method. The developed dynamic model was validated for 2 sinusoidal temperature profiles, 5 to 15 °C (for 600 h) and 10 to 40 °C (for 52 h) with corresponding root mean squared error values of 0.28 and 0.23 log CFU/mL, respectively, between predicted and observed Salmonella spp. populations. The developed dynamic model can be used to predict the growth of Salmonella spp. in LWE under varying temperature conditions.

Practical Application:  Liquid egg and egg products are widely used in food processing and in restaurant operations. These products can be contaminated with Salmonella spp. during breaking and other unit operations during processing. The raw, liquid egg products are stored under refrigeration prior to pasteurization. However, process deviations can occur such as refrigeration failure, leading to temperature fluctuations above the required temperatures as specified in the critical limits within hazard analysis and critical control point plans for the operations. The processors are required to evaluate the potential growth of Salmonella spp. in such products before the product can be used, or further processed. Dynamic predictive models are excellent tools for regulators as well as the processing plant personnel to evaluate the microbiological safety of the product under such conditions.
Measuring and Predicting Head Space Pressure during Retorting of Thermally Processed Foods
Authors: Ghai Gaurav , Teixeira Arthur A. , Welt Bruce A. , Goodrich‐Schneider Renee , Yang Weihua , Almonacid Sergio
Published: March 2011

Abstract:  Traditional metal cans and glass jars have been the mainstay in thermally processed canned foods for more than a century, but are now sharing shelf space with increasingly popular flexible pouches and semi‐rigid trays. These flexible packages lack the strength of metal cans and glass jars, and need greater control of external retort pressure during processing. Increasing internal package pressure without counter pressure causes volumetric expansion, putting excessive strain on package seals that may lead to serious container deformation and compromised seal integrity. The primary objective of this study was to measure internal pressure build‐up within a rigid air‐tight container (module) filled with various model food systems undergoing a retort process in which internal product temperature and pressure, along with external retort temperature and pressure, were measured and recorded at the same time. The pressure build‐up in the module was compared with the external retort pressure to determine the pressure differential that would cause package distortion in the case of a flexible package system. The secondary objective was to develop mathematical models to predict these pressure profiles in response to known internal temperature and initial and boundary conditions for the case of the very simplest of model food systems (pure water and aqueous saline and sucrose solutions), followed by food systems of increasing compositional complexity (green beans in water and sweet peas in water). Results showed that error between measured and predicted pressures ranged from 2% to 4% for water, saline, and green beans, and 7% to 13% for sucrose solution and sweet peas.

Practical Application:  Flexible packages have limited strength, and need more accurate and closer control of retort pressure during processing. The package becomes more flexible as it heats and might expand with increasing internal pressure that may cause serious deformation or rupture if not properly controlled and/or counterbalanced with external retort pressure. This article describes methods for determining exactly what the retort pressure profile will need to be to avoid this problem during retorting, and mathematical models to predict these pressures in response to known internal temperature and initial/boundary conditions.
Antimicrobial Photodynamic Therapy in the Colon: Delivering a Light Punch to the Guts?
Authors: Wainwright Mark , Dai Tianhong , Hamblin Michael R.
Published: March 2011

A paper in this issue of Photochemistry and Photobiology by Cassidy et al. describes the use of a sophisticated drug delivery vehicle prepared by the hot melt extrusion process to deliver photosensitizers to the colon. The smart vehicle protects its cargo through the acidic environment of the stomach but releases the active photosensitizers in the higher pH and anaerobic environment of the colon. The goal is to use photodynamic therapy (PDT) to destroy pathogenic microorganisms that can cause disease when they grow out of control in the colon. Since the colon is an environment with a low oxygen concentration the investigators also used tetrachlorodecaoxide, an oxygen donor to boost the available oxygen concentration. The paper reports results with Enterococcus faecalis and Bacteroides fragilis but the real medical problem demanding to be solved is Clostridium difficile that can cause intractable drug‐resistant infections after antibiotic use. There still remain barriers to implementing this strategy in vivo, including light delivery to the upper colon, oxygen availability and optimizing the selectivity of photosensitizers for bacteria over colon epithelial cells. Nevertheless, this highly innovative paper lays the ground for the study of an entirely new and significant application for antimicrobial PDT.
The Economics of Director Heterogeneity
Authors: Anderson Ronald C. , Reeb David M. , Upadhyay Arun , Zhao Wanli
Published: March 2011

We investigate the potential costs and benefits of firms constituting a heterogeneous pool of directors relative to more homogeneous boards. We measure director heterogeneity along six separate dimensions and divide board heterogeneity into occupational and social components. Our empirical analysis indicates that corporate complexity and managerial control exhibit significant influence on board heterogeneity. Using the heterogeneity of the county population of the firm's headquarters as an instrument, we also find that investors place valuation premiums on heterogeneous boards in complex firms but discount heterogeneity in less complex firms. Overall, our analysis indicates greater heterogeneity may not necessarily improve board efficacy.
Systemic and Central Immunity in Alzheimer's Disease: Therapeutic Implications
Authors: Butchart Joseph , Holmes Clive
Published: March 2011

Clinical pharmaceutical trials aimed at modulating the immune system in Alzheimer's Disease have largely focused on either dampening down central proinflammatory innate immunity or have manipulated adaptive immunity to facilitate the removal of centrally deposited beta amyloid. To date, these trials have had mixed clinical therapeutic effects. However, a number of clinical studies have demonstrated disturbances of both systemic and central innate immunity in Alzheimer's Disease and attention has been drawn to the close communication pathways between central and systemic immunity. This paper highlights the need to take into account the potential systemic effects of drugs aimed at modulating central immunity and the possibility of developing novel therapeutic approaches based on the manipulation of systemic immunity and its communication with the central nervous system.
High universality of matK primers for barcoding gymnosperms
Authors: LI Yan , GAO Lian‐Ming , POUDEL Ram C. , Li De‐Zhu , FORREST Alan
Published: March 2011

Abstract  DNA barcoding is a tool to provide rapid and accurate taxonomic identification using a standard DNA region. A two‐marker combination of matK+rbcL was formally proposed as the core barcode for land plants by the Consortium for the Barcode of Life Plant Working Group. However, there are currently no barcoding primers for matK showing high universality in gymnosperms. We used 57 gymnosperm species representing 40 genera, 11 families and four subclasses to evaluate the universality of nine candidate matK primers and one rbcL primer in this study. Primer (1F/724R) of rbcL is proposed here as a universal primer for gymnosperms due to high universality. One of the nine candidate matK primers (Gym_F1A/Gym_R1A) is proposed as the best “universal”matK primer for gymnosperms because of high polymerase chain reaction success and routine generation of high quality bidirectional sequences. A specific matK primer for Ephedra was newly designed in this study, which performed well on the sampled species. The primers proposed here for rbcL and matK can be easily and successfully amplified for most gymnosperms.
Application of DNA barcodes in Hedyotis L. (Spermacoceae, Rubiaceae)
Authors: GUO Xing , SIMMONS Mark P. , BUT Paul Pui‐Hay , SHAW Pang‐Chui , WANG Rui‐Jiang
Published: March 2011

Abstract  The potential application of DNA barcodes of plastid (matK, trnH–psbA, petD, and rbcL) and nuclear (internal transcribed spacer (ITS) of rDNA) DNA regions was investigated for 25 Hedyotis taxa. The ITS showed the best species discrimination by resolving 23 of the species as exclusive lineages with no shared alleles between any of the 24 distinct species (H. assimilis and H. mellii are not supported as distinct species based on our molecular and morphological data). Conversely, rbcL performed the worst and only resolved 10 of the species as exclusive lineages, and 10 species with shared alleles. Using ITS has the advantage of high PCR amplification success and it provides good intra‐ and interspecific variation distribution patterns. The most powerful plastid markers were petD and trnH–psbA, but we could amplify and sequence trnH–psbA for only 83% of the accessions sampled. Combination of ITS and petD performed extremely well, with all 24 of the distinct species resolved as exclusive lineages and no shared alleles between any of the distinct species. We therefore recommend ITS, or a combination of ITS and petD, as the standard DNA barcode in Hedyotis, but acknowledge that there are no shared alleles between distinct species for matK and rbcL combined.