bluuebunny/crossref_metadata_2025 huggingface dataset:
Do variations in hospital mortality patterns after weekend admission reflect reduced quality of care or different patient cohorts? A population-based study
Authors: Concha Oscar Perez , Gallego Blanca , Hillman Ken , Delaney Geoff P , Coiera Enrico
Published: October 2013

Background

Proposed causes for increased mortality following weekend admission (the ‘weekend effect’) include poorer quality of care and sicker patients. The aim of this study was to analyse the 7 days post-admission time patterns of excess mortality following weekend admission to identify whether distinct patterns exist for patients depending upon the relative contribution of poorer quality of care (care effect) or a case selection bias for patients presenting on weekends (patient effect).

Methods

Emergency department admissions to all 501 hospitals in New South Wales, Australia, between 2000 and 2007 were linked to the Death Registry and analysed. There were a total of 3 381 962 admissions for 539 122 patients and 64 789 deaths at 1 week after admission. We computed excess mortality risk curves for weekend over weekday admissions, adjusting for age, sex, comorbidity (Charlson index) and diagnostic group.

Results

Weekends accounted for 27% of all admissions (917 257/3 381 962) and 28% of deaths (18 282/64 789). Sixteen of 430 diagnosis groups had a significantly increased risk of death following weekend admission. They accounted for 40% of all deaths, and demonstrated different temporal excess mortality risk patterns: early care effect (cardiac arrest); care effect washout (eg, pulmonary embolism); patient effect (eg, cancer admissions) and mixed (eg, stroke).

Conclusions

The excess mortality patterns of the weekend effect vary widely for different diagnostic groups. Recognising these different patterns should help identify at-risk diagnoses where quality of care can be improved in order to minimise the excess mortality associated with weekend admission.
Improving management of patients with hyperemesis
Authors: Lloyd Jilly , Ramskill Nikki , Sharma Bhavna
Published: October 2013

Hyperemesis gravidarum (HG), defined as severe nausea and vomiting resulting in dehydration, is a common reason for emergency admission in gynaecology (1). The management of HG is supportive, including the correction of dehydration and electrolyte disturbances and use of antiemetics.

An audit in our unit identified that women with HG were not receiving appropriate fluid resuscitation and in particular inadequate potassium replacement. A proforma was developed by a multidiscplinary team to prompt appropriate investigations, medications, and fluid resuscitation. The proforma was introduced in paper format and electronically, accompanied by an education programme for junior doctors.

This intervention has improved prescribing practice and fluid resuscitation for these patients. Length of admission has reduced. Efforts have been made to ensure this change is sustainable in the long term, through involvement of the junior doctors using the proforma at all stages of the project.
Improving the inpatient oncology experience through a new consultant ward round
Authors: Navani Vishal
Published: October 2013

Regular consultant ward rounds have been shown to reduce the length of stay and improve the discharge planning for patients (1). To balance the competing demands of outpatient activity and inpatient oncology, it has been difficult to provide specialist care in our hospital. Previously, inpatients were managed primarily by the oncology specialist trainees, who are qualified in internal medicine, with an ad-hoc review by their named consultant. A regular consultant ward round was introduced for the first time on the 7/1/13. Each consultant was timetabled to give a twice weekly morning ward round on a rolling rota.

To evaluate this intervention, a retrospective case note analysis was undertaken. This included all patients admitted under oncology for the two months preceding and succeeding the new ward round. For each patient the admission date, time to first consultant review, number of consultant reviews, time to discharge after consultant review, and discharge date was identified. A staff survey also took place. Statistical analysis was performed using Mann-Whitney U or Chi-Squared tests.

85 patient episodes met the inclusion criteria. Case notes were available for 63 episodes (74%). The average length of stay significantly decreased from 11 days to three and half days (p<0.05). The time to discharge after first consultant review also significantly decreased from six days to two days (p<0.05). The number of consultant reviews and time to first consultant review remained unchanged (p>0.05). The percentage of patients receiving a consultant review increased, from 54.3% to 71.4%, though this was not statistically significant. However it is likely such a large increase is clinically significant. Medical and nursing staff satisfaction also improved.

This study suggests that a regular consultant ward round improves length of stay for patients. This is possibly because an increase in patients received a consultant review and that the treatment and discharge decisions were expedited after such a review.
Assessing the expenditure distribution of animal health surveillance: the case of Great Britain
Authors: Drewe J.A. , Häsler B. , Rushton J. , Stärk K. D. C.
Published: October 2013

Animal health surveillance in Great Britain (GB) is conducted through public and private initiatives, yet there is no consolidated information on these activities and their outcomes. We developed an inventory of livestock health surveillance programmes in GB to identify gaps in resource use and potential synergies that could be exploited. The inventory contained details of 36 livestock surveillance activities active in 2011. Data were collected by questionnaire and interviews. Livestock health surveillance funding was found to be unevenly distributed between species: the vast majority (approximately 94 per cent) was spent on cattle diseases (tuberculosis surveillance accounted for most of this expenditure), with 2 per cent on pigs, 2 per cent on sheep/goats, 1 per cent on poultry, and 1 per cent on antimicrobial resistance surveillance across all species. Consequently, surveillance efforts in GB appears heavily skewed towards regions with high cattle densities, particularly high‐prevalence tuberculosis areas such as the southwest. The contribution of private schemes to surveillance funding was hard to quantify due to limited access to data, but was estimated to be about 10 per cent. There is scope to better understand the benefits of surveillance, enhance data sharing, clarify costs and identify who pays and who gains. Health surveillance should be considered within the sharing of responsibilities for disease control.
Elevated levels of δ15N in riverine Painted Turtles (Chrysemys picta): trophic enrichment or anthropogenic input?
Authors: Hofmeister Natalie R. , Welk Megan , Freedberg Steven
Published: October 2013

The natural abundance of stable isotopes of elements in animal tissue is influenced by both biotic and abiotic factors. Biotically, animals feeding at higher trophic levels are enriched in the ratio of 15N:14N (δ15N) relative to their food resources owing to the preferential excretion of 14N. Abiotically, increases in δ15N may also reflect different sources of biologically available nitrogen, including nitrogen resulting from denitrification of inorganic fertilizer. We studied variation in δ15N among freshwater turtle populations to assess spatial variation in δ15N and to determine whether this variation can be attributed to differences in nitrogen source or trophic enrichment. We examined nitrogen and carbon stable isotope ratios in duckweed (genus Lemna L.) and in Painted Turtles (Chrysemys picta (Schneider, 1783)) in aquatic ecosystems expected to be differentially affected by agricultural activity and denitrification of inorganic fertilizer. Across sites, C. picta δ15N was strongly correlated with Lemna δ15N and was elevated in sites influenced by agricultural activity. Furthermore, trophic position of turtles was not associated with δ15N but was consistent with expected values for primary consumers in freshwater systems, indicating that differences in tissue δ15N could be attributed to differences in initial sources of nitrogen in each ecosystem. Our results suggest that care must be taken when attributing differences in isotopic values of animal populations to trophic factors.
Local and migratory movements of humpback whales (Megaptera novaeangliae) satellite-tracked in the North Atlantic Ocean
Authors: Kennedy A.S. , Zerbini A.N. , Vásquez O.V. , Gandilhon N. , Clapham P.J. , Adam O.
Published: October 2013

North Atlantic humpback whales (Megaptera novaeangliae (Borowski, 1781)) migrate from high-latitude summer feeding grounds to low-latitude winter breeding grounds along the Antillean Island chain. In the winters and springs of 2008 through 2012, satellite tags were deployed on humpback whales on Silver Bank (Dominican Republic) and in Guadeloupe (French West Indies) breeding areas. Whales were monitored, on average, for 26 days (range = 4–90 days). Some animals remained near their tagging location for multiple days before beginning their northerly migration, yet some visited habitats along the northwestern coast of the Dominican Republic, northern Haiti, the Turks and Caicos islands, and off Anguilla. Individuals monitored during migration headed towards feeding grounds in the Gulf of Maine (USA), Canada, and the eastern North Atlantic (Iceland or Norway). One individual traveled near Bermuda during the migration. This study provides the first detailed description of routes used by North Atlantic humpback whales towards multiple feeding destinations. Additionally, it corroborates previous research showing that individuals from multiple feeding grounds migrate to the Antilles for the breeding season. This study indicates that North Atlantic humpbacks use an area broader than the existing boundaries of marine mammal sanctuaries, which should provide justification for their expansion.
The term ‘Anthropocene’ in the context of formal geological classification
Authors: Gibbard P. L. , Walker M. J. C.
Published: October 2013

In recent years, ‘Anthropocene’ has been proposed as an informal stratigraphic term to denote the current interval of anthropogenic global environmental change. A case has also been made to formalize it as a series/epoch, based on the recognition of a suitable marker event, such as the start of the Industrial Revolution in northern Europe. For the Anthropocene to merit formal definition, a global signature distinct from that of the Holocene is required that is marked by novel biotic, sedimentary and geochemical change. Although there is clear evidence of anthropogenic effects in geological sequences, it is uncertain whether these trends are sufficiently distinct, consistent and dated for the proposal for a Holocene/Anthropocene boundary to be substantiated. The current view of the Earth-Science community is that it should remain informal. For formal definition a Global Stratigraphic Section and Point (GSSP) is required. Adoption of the term ‘Anthropocene’ will ultimately depend on recognition of a global event horizon. Without this, there is no justification for decoupling the Anthropocene from the Holocene. If the Anthropocene is deemed to have utility, it should be as an informal historical designation rather than a formally defined stratigraphic unit (of whatever status) within the geological timescale.
Cyclosporin A in left ventricular remodeling after myocardial infarction
Authors: Kholmukhamedov Andaleb , Logdon Christina , Hu Jiangting , McKinney Richard A. , Spinale Francis G. , Lemasters John J. , Mukherjee Rupak
Published: October 2013

Recent studies suggest that an increase in apoptosis within the myocardium may be a contributing factor for the progression of late adverse left ventricular (LV) remodeling following myocardial infarction (MI). Given that apoptosis is often triggered by induction of the mitochondrial permeability transition (MPT) pore, the goal of this study was to evaluate the therapeutic efficacy of cyclosporin A (CsA), an MPT blocker, to prevent cells from undergoing apoptosis and consequently attenuate late LV remodeling post-MI. MI was induced in C57BL/6 mice and then randomized to either vehicle or CsA groups. Beginning 48 h after surgery after infarction had already occurred, mice were gavaged with CsA (2 mg/kg) or vehicle once daily. LV end-diastolic volume and LV ejection fraction were assessed by echocardiography before MI induction and terminally at either 7 days ( n = 7) or 28 days ( n = 8) post-MI. LV end-diastolic volume increased and LV ejection fraction decreased in all MI groups with no difference between the CsA-treated and untreated groups. After vehicle and CsA, areas of necrosis were present at 7 and 28 days post-MI with no difference between treatment groups. Caspase-3 activity and terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling in distal nonnecrotic LV both increased after MI but were lower in CsA-treated mice compared with vehicle ( P < 0.05). In conclusion, CsA decreased apoptosis occurring late after MI, confirming involvement of a CsA-sensitive MPT in the cell death. However, CsA-mediated reduction in apoptosis in non-MI myocardium was not beneficial against late pump dysfunction occurring during post-MI remodeling.
Postprandial VLDL lipolysis products increase monocyte adhesion and lipid droplet formation via activation of ERK2 and NFκB
Authors: den Hartigh Laura J. , Altman Robin , Norman Jennifer E. , Rutledge John C.
Published: October 2013

Postprandial lipemia is characterized by a transient increase in circulating triglyceride-rich lipoproteins such as very low-density lipoprotein (VLDL) and has been shown to activate monocytes in vivo. Lipolysis of VLDL releases remnant particles, phospholipids, monoglycerides, diglycerides, and fatty acids in close proximity to endothelial cells and monocytes. We hypothesized that postprandial VLDL lipolysis products could activate and recruit monocytes by increasing monocyte expression of proinflammatory cytokines and adhesion molecules, and that such activation is related to the development of lipid droplets. Freshly isolated human monocytes were treated with VLDL lipolysis products (2.28 mmol/l triglycerides + 2 U/ml lipoprotein lipase), and monocyte adhesion to a primed endothelial monolayer was observed using a parallel plate flow chamber coupled with a CCD camera. Treated monocytes showed more rolling and adhesion than controls, and an increase in transmigration between endothelial cells. The increased adhesive events were related to elevated expression of key integrin complexes including Mac-1 [αm-integrin (CD11b)/β2-integrin (CD18)], CR4 [αx-integrin (CD11c)/CD18] and VLA-4 [α4-integrin (CD49d)/β1-integrin (CD29)] on treated monocytes. Treatment of peripheral blood mononuclear cells (PBMCs) and THP-1 monocytes with VLDL lipolysis products increased expression of TNFα, IL-1β, and IL-8 over controls, with concurrent activation of NFkB and AP-1. NFκB and AP-1-induced cytokine and integrin expression was dependent on ERK and Akt phosphorylation. Additionally, fatty acids from VLDL lipolysis products induced ERK2-dependent lipid droplet formation in monocytes, suggesting a link to inflammatory signaling pathways. These results provide novel mechanisms for postprandial monocyte activation by VLDL lipolysis products, suggesting new pathways and biomarkers for chronic, intermittent vascular injury.
Toll-like receptors and damage-associated molecular patterns: novel links between inflammation and hypertension
Authors: McCarthy Cameron G. , Goulopoulou Styliani , Wenceslau Camilla F. , Spitler Kathryn , Matsumoto Takayuki , Webb R. Clinton
Published: October 2013

Low-grade systemic inflammation is a common manifestation of hypertension; however, the exact mechanisms that initiate this pathophysiological response, thereby contributing to further increases in blood pressure, are not well understood. Aberrant vascular inflammation and reactivity via activation of the innate immune system may be the first step in the pathogenesis of hypertension. One of the functions of the innate immune system is to recognize and respond to danger. Danger signals can arise from not only pathogenic stimuli but also endogenous molecules released following cell injury and/or death [damage-associated molecular patterns (DAMPs)]. In the short-term, activation of the innate immune system is beneficial in the vasculature by providing cytoprotective mechanisms and facilitating tissue repair following injury or infection. However, sustained or excessive immune system activation, such as in autoimmune diseases, may be deleterious and can lead to maladaptive, irreversible changes to vascular structure and function. An initial source of DAMPs that enter the circulation to activate the innate immune system could arise from modest elevations in peripheral vascular resistance. These stimuli could subsequently lead to ischemic- or pressure-induced events aggravating further cell injury and/or death, providing more DAMPs for innate immune system activation. This review will address and critically evaluate the current literature on the role of the innate immune system in hypertension pathogenesis. The role of Toll-like receptor activation on somatic cells of the vasculature in response to the release of DAMPs and the consequences of this activation on inflammation, vasoreactivity, and vascular remodeling will be specifically discussed.
Neurovascular signaling in the brain and the pathological consequences of hypertension
Authors: Dunn Kathryn M. , Nelson Mark T.
Published: October 2013

The execution and maintenance of all brain functions are dependent on a continuous flow of blood to meet the metabolic needs of the tissue. To ensure the delivery of resources required for neural processing and the maintenance of neural homeostasis, the cerebral vasculature is elaborately and extensively regulated by signaling from neurons, glia, interneurons, and perivascular nerves. Hypertension is associated with impaired neurovascular regulation of the cerebral circulation and culminates in neurodegeneration and cognitive dysfunction. Here, we review the physiological processes of neurovascular signaling in the brain and discuss mechanisms of hypertensive neurovascular dysfunction.
Effects of exercise training on SFO-mediated sympathoexcitation during chronic heart failure
Authors: Llewellyn Tamra L. , Sharma Neeru M. , Zheng Hong , Patel Kaushik P.
Published: October 2013

Exercise training (ExT) has been shown to reduce sympathetic drive during heart failure (HF). The subfornical organ (SFO) is involved in the neural control of sympathetic drive. We hypothesized that an activated SFO contributes to enhanced sympathetic activity in HF. We also postulated that ExT would reduce the activation of the SFO and its contribution to the sympathetic drive during HF. Sprague-Dawley rats were subjected to coronary artery ligation to induce HF. Rats were assigned to ExT for 3–4 wk. Rats with HF had a 2.5-fold increase in FosB-positive cells in the SFO compared with sham-operated rats, and this was normalized by ExT. Microinjection of ANG II (100 pmol) into the SFO resulted in a greater increase in renal sympathetic nerve activity (RSNA), blood pressure, and heart rate in the HF group than in the sham-operated group. These responses were normalized after ExT (change in RSNA: 23 ± 3% vs. 8 ± 2%). ExT also abolished the decrease in RSNA in HF rats after the microinjection of losartan (200 pmol) into the SFO (−21 ± 4% vs. −2 ± 3%). Finally, there was elevated mRNA (5-fold) and protein expression (43%) of ANG II type 1 receptors in the SFO of rats with HF, which were reversed after ExT. These data suggest that the enhanced activity of the SFO by elevated tonic ANG II contributes to the enhanced sympathoexcitation exhibited in HF. The decrease in ANG II type 1 receptor expression in the SFO by ExT may be responsible for reversing the neuronal activation in the SFO and SFO-mediated sympathoexcitation in rats with HF.
Temporal changes in integrin-mediated cardiomyocyte adhesion secondary to chronic cardiac volume overload in rats
Authors: Stewart James A. , Gardner Jason D. , Brower Gregory L. , Janicki Joseph S.
Published: October 2013

Previous studies have established integrins as cell surface receptors that mediate cardiomyocyte-extracellular matrix (ECM) attachments. This study sought to determine the contributions of the myocardial β1- and β3-integrin subunits to ventricular dilatation and coronary flow regulation using a blood-perfused isolated heart preparation. Furthermore, cardiomyocyte adhesion to collagen types I and IV, fibronectin, and laminin with and without a β1-integrin subunit neutralizing antibody was assessed during the course of remodeling secondary to a sustained cardiac volume overload, including the onset of heart failure. Isolated cardiomyocytes were obtained during the initial, compensated, and decompensated phases of remodeling resulting from an aortocaval fistula created in 8-wk-old male Sprague-Dawley rats. Blocking the β1-integrin subunit in isolated normal hearts produced ventricular dilatation, whereas this was not the case when the β3-subunit was blocked. Substantial reductions in cardiomyocyte adhesion coincided with the previously documented development of ventricular dilatation and decreased contractility postfistula, with the β1-integrin contribution to adhesion ranging from 28% to 73% over the course of remodeling being essentially substrate independent. In contrast, both integrin subunits were found to be involved in regulating coronary vascular resistance. It is concluded that marked reductions in integrin-mediated cardiomyocyte adhesion to the ECM play a significant role in the progression of adverse myocardial remodeling that leads to heart failure. Furthermore, although both the β1- and β3-integrin subunits were involved in regulating coronary vascular resistance, only inhibition of β1-integrin-mediated adhesion resulted in ventricular dilatation of the normal heart.
QT/RR curvatures in healthy subjects: sex differences and covariates
Authors: Malik Marek , Hnatkova Katerina , Kowalski Donna , Keirns James J. , van Gelderen E. Marcel
Published: October 2013

Data of a large clinical study were used to investigate how much are the QT/RR patterns in healthy subjects curved and whether these curvatures differ between women and men. Daytime drug-free 12-lead Holter recordings were repeated 4 times in each of 176 female healthy subjects and 176 male healthy subjects aged 32.7 ± 9.1 yr. In each of the subjects, up to 1,440 carefully verified QT interval measurements were obtained with QT/RR hysteresis-corrected RR intervals. Individual subject data were used to fit the following regression equation: QT = χ + (δ/γ)(1 − RRγ) + ε, where QT and RR are QT and RR measurements (in s), χ is regression intercept, δ is the QT/RR slope, γ is the QT/RR curvature and provides the lowest regression residual, and ε represents normally distributed zero-centered errors. The bootstrap technique showed the intrasubject reproducibility of QT/RR slopes and curvatures. In women and men, QT/RR curvatures were 0.544 ± 0.661 and 0.797 ± 0.706, respectively ( P = 0.0006). The corresponding QT/RR slopes were 0.158 ± 0.030 and 0.139 ± 0.023, respectively ( P < 0.0001). QT/RR curvatures were related to QT/RR slopes but not to individually corrected mean QTc intervals or individual QT/RR hysteresis profiles. The individual heart rate correction formula derived from the curvilinear regression provided a significantly lower intrasubject variability of QTc interval than individual optimisation of linear or log-linear QT/RR heart rate corrections. The QT/RR curvature can be reliable measured and expressed numerically. The corresponding heart rate correction formula provides more compact data than the previously proposed approaches. There are substantial sex differences in QT/RR patterns. Women have a QT/RR pattern that is not only steeper than men but also more curved.
Increased inducibility of ventricular tachycardia and decreased heart rate variability in a mouse model for type 1 diabetes: effect of pravastatin
Authors: Rajab Mohammad , Jin Hongwei , Welzig Charles M. , Albano Alfred , Aronovitz Mark , Zhang Yali , Park Ho-Jin , Link Mark S. , Noujaim Sami F. , Galper Jonas B.
Published: October 2013

Although a reduction in the high-frequency (HF) component of heart rate variability (HRV) is a major complication of diabetes and a risk factor for sudden death, its relationship to ventricular tachycardia (VT) is unknown. We developed a mouse model for the study of VT and its relationship to changes in HRV in the Akita type 1 diabetic mouse. Programmed ventricular stimulation of anesthetized mice demonstrated that Akita mice were more inducible for VT compared with wild-type mice: 78.6% versus 28.6% ( P = 0.007). Optical mapping of perfused hearts demonstrated multifocal breakthroughs that occasionally gave rise to short-lived rotors consistent with focal initiation and maintenance of VT. Treatment of Akita mice with pravastatin, which had been previously shown clinically to decrease ventricular ectopy and to increase HRV, decreased the inducibility of VT: 36.8% compared with 75.0% with placebo treatment ( P = 0.022). The HF fraction of HRV was reduced in Akita mice (48.6 ± 5.2% vs. 70.9 ± 4.8% in wild-type mice, P = 0.005) and was increased compared with placebo treatment in pravastatin-treated mice. Pretreatment of Akita mice with the muscarinic agonist carbamylcholine or the β-adrenergic receptor blocker propranolol decreased the inducibility of VT ( P = 0.001). In conclusion, the increased inducibility of focally initiated VT and reduced HF fraction in Akita mice were partially reversed by both pravastatin treatment and pharmacologic reversal of parasympathetic dysfunction. In this new animal model for the study of the pathogenesis of VT in type 1 diabetes, pravastatin may play a role in the prevention of VT by attenuating parasympathetic dysfunction.
Tuning endothelial monolayer adhesion: a neutron reflectivity study
Authors: Pocivavsek Luka , Junghans Ann , Zebda Noureddine , Birukov Konstantin , Majewski Jaroslaw
Published: October 2013

Endothelial cells, master gatekeepers of the cardiovascular system, line its inner boundary from the heart to distant capillaries constantly exposed to blood flow. Interendothelial signaling and the monolayers adhesion to the underlying collagen-rich basal lamina are key in physiology and disease. Using neutron scattering, we report the first ever interfacial structure of endothelial monolayers under dynamic flow conditions mimicking the cardiovascular system. Endothelial adhesion (defined as the separation distance ℓ between the basal cell membrane and solid boundary) is explained using developed interfacial potentials and intramembrane segregation of specific adhesion proteins. Our method provides a powerful tool for the biophysical study of cellular layer adhesion strength in living tissues.
Amplification of steroid-mediated SP-B expression by physiological levels of caffeine
Authors: Fehrholz Markus , Hütten Matthias , Kramer Boris W. , Speer Christian P. , Kunzmann Steffen
Published: October 2013

Factors positively influencing surfactant homeostasis in general and surfactant protein B (SP-B) expression in particular are considered of clinical importance regarding an improvement of lung function in preterm infants. The objective of this study was to identify effects of physiological levels of caffeine on glucocorticoid-mediated SP-B expression in vitro and in vivo. Levels of SP-B and pepsinogen C were quantified by quantitative real-time RT-PCR or immunoblotting in NCI-H441 cells daily exposed to caffeine and/or dexamethasone (DEX). In vivo, SP-B expression was analyzed in bronchoalveolar lavage (BAL) of preterm sheep exposed to antenatal DEX and/or postnatal caffeine. If DEX and caffeine were continuously present, SP-B mRNA and protein levels were increased for up to 6 days after induction ( P < 0.05). Additionally, caffeine enhanced SP-B mRNA expression in DEX-pretreated cells ( P < 0.05). Moreover, caffeine amplified DEX-induced pepsinogen C mRNA expression ( P < 0.05). After short-term treatment with caffeine in vivo, only slightly higher SP-B levels could be detected in BAL of preterm sheep following antenatal DEX, combined with an increase of arterial oxygen partial pressure ( P < 0.01). Our data demonstrated that the continuous presence of caffeine in vitro is able to amplify DEX-mediated SP-B expression. In contrast, short-term improvement of lung function in vivo is likely to be independent of altered SP-B transcription and translation. An impact of caffeine on release of surfactant reservoirs from lamellar bodies could, however, quickly affect SP-B content in BAL, which has to be further investigated. Our findings indicate that caffeine is able to amplify main effects of glucocorticoids that result from changes in surfactant production, maturation, and release.
On the Convergence Analysis of the Alternating Direction Method of Multipliers with Three Blocks
Authors: Chen Caihua , Shen Yuan , You Yanfei
Published: October 2013

We consider a class of linearly constrained separable convex programming problems whose objective functions are the sum of three convex functions without coupled variables. For those problems, Han and Yuan (2012) have shown that the sequence generated by the alternating direction method of multipliers (ADMM) with three blocks converges globally to their KKT points under some technical conditions. In this paper, a new proof of this result is found under new conditions which are much weaker than Han and Yuan’s assumptions. Moreover, in order to accelerate the ADMM with three blocks, we also propose a relaxed ADMM involving an additional computation of optimal step size and establish its global convergence under mild conditions.
Diffraction of a Plane Elastic Wave by a Gradient Transversely Isotropic Layer
Authors: Anufrieva Anastasiia , Tumakov Dmitrii
Published: October 2013

The problem of diffraction of a plane elastic wave by a gradient transversely isotropic layer is considered.
Using the method of overdetermined boundary value problem in combination with the Fourier transform method, the system of ordinary differential equations of the second order with boundary conditions of the third type is obtained which is solved by the grid method. Results of calculations
obtained using the above-mentioned technique for the case of piecewise linear profiles for the Young modulus of the layer are given.
Successful Management of Metastatic Eccrine Porocarcinoma
Authors: Aaribi Imane , Mohtaram Amina , Ben Ameur El Youbi Meryam , Kharmoum Jinane , El Kabous Mustapha , Mrabti Hind , El Khannoussi Basma , Errihani Hassan
Published: October 2013

Eccrine porocarcinoma (EPC) is a rare tumor. It develops from the intraepidermal ductal portion of the eccrine sweat gland. Metastatic disease is rare. We report a new case of metastatic eccrine porocarcinoma with a successful management and a good response to docetaxel. A 54-year-old man was admitted with a mass in the breast. Biopsy specimen found carcinomatous tumor proliferation with large anastomosing ducts. Cellular atypia were noted, with eosinophilic cytoplasm and round to oval nuclei. The tumor showed positive immunoreactivity for ACE and negative to anti-PS-100. Resection was performed. One year later, he presented with local and metastatic recurrences. The patient had received 3 cycles of cisplatin and 5-fluorouracil; he progressed with increase in mass size and number of lung lesions. He has been undergoing three cycles of docetaxel with complete response in the lung and regression of the breast mass. The mass was excised. Porocarcinoma is a very rare entity and poorly understood. In the metastatic phase, it has modest or no sensitivity to anticancer treatment. Docetaxel should be considered in the metastatic eccrine porocarcinoma.
Electrostrictive Energy Conversion of Polyurethane with Different Hard Segment Aggregations
Authors: Sukwisute Pisan , Koyvanitch Krit , Putson Chatchai , Muensit Nantakan
Published: October 2013

This work reported the electrostriction of polyurethane (PU) with different aggregations of hard segments (HS) controlled by dissimilar solvents: N,N-dimethylformamide (DMF) and a mixture of dimethyl sulfoxide and acetone denoted as DMSOA. By using atomic force microscopy and differential scanning calorimetry, the PU/DMSOA was observed to have larger HS domains and smoother surface when compared to those of the PU/DMF. The increase of HS domain formation led to the increase of transition temperature, enthalpy of transition, and dielectric constant (0.1 Hz). For the applied electric field below 4 MV/m, the PU/DMSOA had higher electric-field-induced strain and it was opposite otherwise. Dielectric constant and Young’s modulus for all the samples were measured. It was found that PU/DMF had less dielectric constant, leading to its lower electrostrictive coefficient at low frequency. At higher frequencies the electrostrictive coefficient was independent of the solvent type. Consequently, their figure of merit and power harvesting density were similar. However, the energy conversion was well exhibited for low frequency range and low electric field. The PU/DMSOA should, therefore, be promoted because of high vaporizing temperature of the DMSOA, good electrostriction for low frequency, and high induced strain for low applied electric field.
Numerical Simulation of Particle Flow Motion in a Two-Dimensional Modular Pebble-Bed Reactor with Discrete Element Method
Authors: Liu Guodong , Zhang Yining , Lu Huilin , You Ersheng , Li Xiang
Published: October 2013

Modular pebble-bed nuclear reactor (MPBNR) technology is promising due to its attractive features such as high fuel performance and inherent safety. Particle motion of fuel and graphite pebbles is highly associated with the performance of pebbled-bed modular nuclear reactor. To understand the mechanism of pebble’s motion in the reactor, we numerically studied the influence of number ratio of fuel and graphite pebbles, funnel angle of the reactor, height of guide ring on the distribution of pebble position, and velocity by means of discrete element method (DEM) in a two-dimensional MPBNR. Velocity distributions at different areas of the reactor as well as mixing characteristics of fuel and graphite pebbles were investigated. Both fuel and graphite pebbles moved downward, and a uniform motion was formed in the column zone, while pebbles motion in the cone zone was accelerated due to the decrease of the cross sectional flow area. The number ratio of fuel and graphite pebbles and the height of guide ring had a minor influence on the velocity distribution of pebbles, while the variation of funnel angle had an obvious impact on the velocity distribution. Simulated results agreed well with the work in the literature.
Non-Foster Impedance Wideband Matching Technique for Electrically Small Active Antenna
Authors: Li Wenxing , Zhai Ning , Chen Ruilong , Yu Wenhua
Published: October 2013

This paper investigates a non-Foster wideband circuit matching technique for an electrically small antenna (ESA). By introducing a negative impedance convertor into an active network, the active network can obtain an equivalent input gain at input port to improve gain, sensitivity and output ratio of signal to noise. In addition, it also increases the effective height of active antenna. The experimental results have verified the proposed method by using a 100 KHz–30 MHz wideband active receiving monopole antenna.
A Topology Structure Based Outer Membrane Proteins Segment Alignment Method
Authors: Wang Han , Liu Bo , Sun Pingping , Ma Zhiqiang
Published: October 2013

Outer membrane proteins (OMPs) are transmembrane proteins (TMPs) located in outer membranes. These proteins perform diverse biochemical functions and have immediate medical relevance, so that their spatial structures are important for studying. But the special physicochemical properties of OMP make it hard to obtain their structures experimentally. For the purpose of predicting OMP structures, discriminating OMPs and aligning their sequences to native structures are indispensable steps. We developed a novel method OMSA (Outer Membrane Segment Alignment), which implemented both steps in one program. OMSA integrates OMP-specific topology features to implement a sequence-to-structure alignment, for example, segment type and segment orientation, while a segment-dependent gap penalty model is employed to improve the alignment. Compared to peer top-leading methods, OMSA achieved higher accuracy in both OMP discrimination and alignment, which may further improve OMP structure studying.
A Kinetic Study of Micronization Grinding of Dry Mica in a Planetary Ball Mill
Authors: Andrić Ljubiša , Terzić Anja , Aćimović-Pavlović Zagorka , Trumić Milan , Petrov Milan , Pavlović Ljubica
Published: October 2013

This paper presents results of the research of micronization grinding of dry mica in a planetary ball mill. Investigation was conducted in order to improve the quality and to obtain clearly defined properties and characteristics of mica powder. The micronization grinding of dry mica was performed in four time periods: 30, 60, 120, and 360 minutes. The micronized powder was investigated by means of differential thermal and thermogravimetric analyses, analysis of the degree of micronization, the specific surface area analysis, and X-ray diffraction analysis. The achieved results pointed out that dry mica micronization grinding which exceeds 360 minutes is recommended for this type of mill. However, it was also shown that the micronized mica produced by means of planetary ball mill after extra long periods of micronization grinding can pass into amorphous state.
Feasibility of RNA and DNA Extraction from Fresh Pipelle and Archival Endometrial Tissues for Use in Gene Expression and SNP Arrays
Authors: Kissel Heather D. , Paulson Thomas G. , Liu Karen , Li Xiaohong , Swisher Elizabeth , Garcia Rochelle , Sanchez Carissa A. , Reid Brian J. , Reed Susan D. , Doherty Jennifer Anne
Published: October 2013

Identifying molecular markers of endometrial hyperplasia (neoplasia) progression is critical to cancer prevention. To assess RNA and DNA quantity and quality from routinely collected endometrial samples and evaluate the performance of RNA- and DNA-based arrays across endometrial tissue types, we collected fresh frozen (FF) Pipelle, FF curettage, and formalin-fixed paraffin-embedded (FFPE) hysterectomy specimens (benign indications) from eight women. Additionally, neoplastic and uninvolved tissues from 24 FFPE archival hysterectomy specimens with endometrial hyperplasias and carcinomas were assessed. RNA was extracted from 15 of 16 FF and 51 of 51 FFPE samples, with yields >1.2 μg for 13/15 (87%) FF and 50/51 (98%) FFPE samples. Extracted RNA was of high quality; all samples performed successfully on the Illumina whole-genome cDNA-mediated annealing, selection, extension, and ligation (WG-DASL) array and performance did not vary by tissue type. While DNA quantity from FFPE samples was excellent, quality was not sufficient for successful performance on the Affymetrix SNP Array 6.0. In conclusion, FF Pipelle samples, which are minimally invasive, yielded excellent quantity and quality of RNA for gene expression arrays (similar to FF curettage) and should be considered for use in genomic studies. FFPE-derived DNA should be evaluated on new rapidly evolving sequencing platforms.
Dynamics of a Stage Structured Pest Control Model in a Polluted Environment with Pulse Pollution Input
Authors: Liu Bing , Xu Ling , Kang Baolin
Published: October 2013

By using pollution model and impulsive delay differential equation, we formulate a pest control model with stage structure for natural enemy in a polluted environment by introducing a constant periodic pollutant input and killing pest at different fixed moments and investigate the dynamics of such a system. We assume only that the natural enemies are affected by pollution, and we choose the method to kill the pest without harming natural enemies. Sufficient conditions for global attractivity of the natural enemy-extinction periodic solution and permanence of the system are obtained. Numerical simulations are presented to confirm our theoretical results.
Transport Reversal during Heteroexchange: A Kinetic Study
Authors: Makarov V. , Kucheryavykh L. , Kucheryavykh Y. , Rivera A. , Eaton M. J. , Skatchkov S. N. , Inyushin M.
Published: October 2013

It is known that secondary transporters, which utilize transmembrane ionic gradients to drive their substrates up a concentration gradient, can reverse the uptake and instead release their substrates. Unfortunately, theMichaelis-Mentenkinetic scheme, which is popular in transporter studies, does not include transporter reversal, and it completely neglects the possibility of equilibrium between the substrate concentrations on both sides of the membrane. We have developed a complex two-substrate kinetic model that includes transport reversal. This model allows us to construct analytical formulas allowing the calculation of a “heteroexchange” and “transacceleration” using standard Michaelis coefficients for respective substrates. This approach can help to understand how glial and other cells accumulate substrates without synthesis and are able to release such substrates and gliotransmitters.
PrionsEx Vivo: What Cell Culture Models Tell Us about Infectious Proteins
Authors: Krauss Sybille , Vorberg Ina
Published: October 2013

Prions are unconventional infectious agents that are composed of misfolded aggregated prion protein. Prions replicate their conformation by template-assisted conversion of the endogenous prion protein PrP. Templated conversion of soluble proteins into protein aggregates is also a hallmark of other neurodegenerative diseases. Alzheimer’s disease or Parkinson’s disease are not considered infectious diseases, although aggregate pathology appears to progress in a stereotypical fashion reminiscent of the spreading behavior ofmammalian prions. While basic principles of prion formation have been studied extensively, it is still unclear what exactly drives PrP molecules into an infectious, self-templating conformation. In this review, we discuss crucial steps in the life cycle of prions that have been revealed inex vivomodels. Importantly, the persistent propagation of prions in mitotically active cells argues that cellular processes are in place that not only allow recruitment of cellular PrP into growing prion aggregates but also enable the multiplication of infectious seeds that are transmitted to daughter cells. Comparison of prions with other protein aggregates demonstrates that not all the characteristics of prions are equally shared by prion-like aggregates. Future experiments may reveal to which extent aggregation-prone proteins associated with other neurodegenerative diseases can copy the replication strategies of prions.
Folic Acid-Chitosan Conjugated Nanoparticles for Improving Tumor-Targeted Drug Delivery
Authors: Song Huijuan , Su Chang , Cui Wenyu , Zhu Bingya , Liu Liwei , Chen Zhenhua , Zhao Liang
Published: October 2013

Objective. To prepare folic acid-chitosan conjugated nanoparticles (FA-CS NPs) and evaluate their targeting specificity on tumor cells.Methods. Chitosan (CS) NPs were prepared by ionic cross linking method, and folic acid (FA) was conjugated with CS NPs by electrostatic interaction. The properties of NPs were investigated, and doxorubicin hydrochloride (Dox) as a model drug was encapsulated for investigating drug release patternin vitro. The cytotoxicity and cellular uptake of FA-CS NPs were also investigated.Results. The results reveal that the obtained FA-CS NPs were monodisperse nanoparticles with suitable average size and positive surface charge. Dox was easily loaded into FA-CS NPs, and the release pattern showed a long and biphasic drug release. Noticeable phagocytosis effect was observed in the presence of rhodamine B-labeled FA-CSNPs when incubating with the folate receptor-positive SMMC-7221 cells.Conclusion. Compared with the unmodified CS NPs, FA-CS NPs showed much higher cell uptaking ability due to the known folate-receptor mediated endocytosis. FA-CS NPs provide a potential way to enhance the using efficiency of antitumor drug by folate receptor mediated targeting delivery.
Homoclinic Bifurcations in Planar Piecewise-Linear Systems
Authors: Xu Bin , Yang Fenghong , Tang Yun , Lin Mu
Published: October 2013

The problem of homoclinic bifurcations in planar continuous piecewise-linear systems with two zones is studied. This is accomplished by investigating the existence of homoclinic orbits in the systems. The systems with homoclinic orbits can be divided into two cases: the visible saddle-focus (or saddle-center) case and the case of twofold nodes with opposite stability. Necessary and sufficient conditions for the existence of homoclinic orbits are provided for further study of homoclinic bifurcations. Two kinds of homoclinic bifurcations are discussed: one is generically related to nondegenerate homoclinic orbits; the other is the discontinuity induced homoclinic bifurcations related to the boundary. The results show that at least two parameters are needed to unfold all possible homoclinc bifurcations in the systems.
Footstep and Vehicle Detection Using Slow and Quick Adaptive Thresholds Algorithm
Authors: Koç Gökhan , Yegin Korkut
Published: October 2013

An algorithm is developed for footstep, vehicle, and rain detection using seismic sensors operating in a wireless sensor network. Each standalone seismic sensor is coupled with a wireless node, and alarm conditions were evaluated at the sensor rather than at the gateway. The algorithm utilizes slow and quick adaptive thresholds to eliminate static and dynamic noise to check for any disturbance. Duration calculation and filters were used to identify the correct alarm condition. The algorithm was performed on preliminary field tests, and detection performance was verified. Footstep alarm condition up to 8 meters and vehicle presence alarm condition up to 50 meters were observed. Presence of rain did not create any alarm condition. Detection based on kurtosis was also performed and shortcomings of kurtosis especially for vehicle detection were discussed, proposed algorithm has minimal load on the sensor board and its data processing unit; thus, it is energy efficient and suitable for wireless sensor alarm networks.
Particle Production in Ultrarelativistic Heavy-Ion Collisions: A Statistical-Thermal Model Review
Authors: Tiwari S. K. , Singh C. P.
Published: October 2013

The current status of various thermal and statistical descriptions of particle production in the ultrarelativistic heavy-ion collisions experiments is presented in detail. We discuss the formulation of various types of thermal models of a hot and dense hadron gas (HG) and the methods incorporated in the implementing of the interactions between hadrons. It includes our new excluded-volume model which is thermodynamically consistent. The results of the above models together with the experimental results for various ratios of the produced hadrons are compared. We derive some new universal conditions emerging at the chemical freeze-out of HG fireball showing independence with respect to the energy as well as the structure of the nuclei used in the collision. Further, we calculate various transport properties of HG such as the ratio of shear viscosity-to-entropy using our thermal model and compare with the results of other models. We also show the rapidity as well as transverse mass spectra of various hadrons in the thermal HG model in order to outline the presence of flow in the fluid formed in the collision. The purpose of this review article is to organize and summarize the experimental data obtained in various experiments with heavy-ion collisions and then to examine and analyze them using thermal models so that a firm conclusion regarding the formation of quark-gluon plasma (QGP) can be obtained.