bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical Study of Articulating Turbine Rotor Blade Concept for Improved Off-Design Performance of Gas Turbine Engines
Authors: Murugan Muthuvel , Ghoshal Anindya , Xu Fei , Hsu Ming-Chen , Bazilevs Yuri , Bravo Luis , Kerner Kevin
Published: March 2017

Gas turbine engines are generally optimized to operate at nearly a fixed speed with fixed blade geometries for the design operating condition. When the operating condition of the engine changes, the flow incidence angles may not be optimum with the blade geometry resulting in reduced off-design performance. Articulating the pitch angle of turbine blades in coordination with adjustable nozzle vanes can improve performance by maintaining flow incidence angles within the optimum range at all operating conditions of a gas turbine engine. Maintaining flow incidence angles within the optimum range can prevent the likelihood of flow separation in the blade passage and also reduce the thermal stresses developed due to aerothermal loads for variable speed gas turbine engine applications. U.S. Army Research Laboratory (ARL) has partnered with University of California San Diego and Iowa State University Collaborators to conduct high fidelity stator–rotor interaction analysis for evaluating the aerodynamic efficiency benefits of articulating turbine blade concept. The flow patterns are compared between the baseline fixed geometry blades and articulating conceptual blades. The computational fluid dynamics (CFD) studies were performed using a stabilized finite element method developed by the Iowa State University and University of California San Diego researchers. The results from the simulations together with viable smart material-based technologies for turbine blade actuations are presented in this paper.
Onymity promotes cooperation in social dilemma experiments
Authors: Wang Zhen , Jusup Marko , Wang Rui-Wu , Shi Lei , Iwasa Yoh , Moreno Yamir , Kurths Jürgen
Published: March 2017

Researchers test whether and how onymity, as opposed to anonymity, promotes cooperation in a social dilemma experiment.
Enzymes offer waste-to-energy solution
Authors: Peplow Mark
Published: March 2017

Facility digests unsorted garbage to produce green power but could threaten recycling
Breathing to inspire and arouse
Authors: Sheikhbahaei Shahriar , Smith Jeffrey C.
Published: March 2017

A small population of brainstem neurons connects breathing behavior to brain arousal.
PhaR, a Negative Regulator of PhaP, Modulates the Colonization of a Burkholderia Gut Symbiont in the Midgut of the Host Insect, Riptortus pedestris
Authors: Jang Seong Han , Jang Ho Am , Lee Junbeom , Kim Jong Uk , Lee Seung Ah , Park Kyoung-Eun , Kim Byung Hyun , Jo Yong Hun , Lee Bok Luel
Published: March 2017

Five genes encoding PhaP family proteins and one
phaR
gene have been identified in the genome of
Burkholderia
symbiont strain RPE75. PhaP proteins function as the surface proteins of polyhydroxyalkanoate (PHA) granules, and the PhaR protein acts as a negative regulator of PhaP biosynthesis. Recently, we characterized one
phaP
gene to understand the molecular cross talk between
Riptortus
insects and
Burkholderia
gut symbionts. In this study, we constructed four other
phaP
gene-depleted mutants (Δ
phaP1
, Δ
phaP2
, Δ
phaP3
, and Δ
phaP4
mutants), one
phaR
gene-depleted mutant, and a
phaR
-complemented mutant (Δ
phaR/phaR
mutant). To address the biological roles of four
phaP
family genes and the
phaR
gene during insect-gut symbiont interaction, these
Burkholderia
mutants were fed to the second-instar nymphs, and colonization ability and fitness parameters were examined.
In vitro
, the Δ
phaP3
and Δ
phaR
mutants cannot make a PHA granule normally in a stressful environment. Furthermore, the Δ
phaR
mutation decreased the colonization ability in the host midgut and negatively affected the host insect's fitness compared with wild-type
Burkholderia
-infected insects. However, other
phaP
family gene-depleted mutants colonized well in the midgut of the fifth-instar nymph insects. However, in the case of females, the colonization rate of the Δ
phaP3
mutant was decreased and the host's fitness parameters were decreased compared with the wild-type-infected host, suggesting that the environment of the female midgut may be more hostile than that of the male midgut. These results demonstrate that PhaR plays an important role in the biosynthesis of PHA granules and that it is significantly related to the colonization of the
Burkholderia
gut symbiont in the host insects' midgut.

IMPORTANCE
Bacterial polyhydroxyalkanoate (PHA) biosynthesis is a complex process requiring several enzymes. The biological roles of PHA granule synthesis enzymes and the surface proteins of PHA granules during host-gut symbiont interactions are not fully understood. Here, we report the effects on colonization ability in the host midguts and the fitness of host insects after feeding
Burkholderia
mutant cells (four
phaP
-depleted mutants and one
phaR
-depleted mutant) to the host insects. Analyses of both synthesized PHA granule amounts and CFU numbers suggest that the
phaR
gene is closely related to synthesis of the PHA granule and the colonization of the
Burkholderia
gut symbiont in the host insect's midgut. Like our previous report, this study also supports the idea that the environment of the host midgut may not be favorable to symbiotic
Burkholderia
cells and that PHA granules may be required to adapt in the host midgut.
A Newly Determined Member of the
meso
-Diaminopimelate Dehydrogenase Family with a Broad Substrate Spectrum
Authors: Gao Xiuzhen , Zhang Zheng , Zhang Ya'nan , Li Ying , Zhu Heng , Wang Sheng , Li Cun
Published: March 2017

meso
-Diaminopimelate dehydrogenase (
meso
-DAPDH) from
Symbiobacterium thermophilum
(StDAPDH) is the first member of the
meso
-DAPDH family known to catalyze the asymmetric reductive amination of 2-keto acids to produce
d
-amino acids. It is important to understand the catalytic mechanisms of StDAPDH and other enzymes in this family. In this study, based on an evolutionary analysis and examination of catalytic activity, the
meso
-DAPDH enzymes can be divided into two types. Type I showed highly preferable activity toward
meso
-diaminopimelate (
meso
-DAP), and type II exhibited obviously reversible amination activity with a broad substrate spectrum. StDAPDH belongs to type II. A quaternary structure analysis revealed that insertions/deletions (indels) and a loss of quaternary structure resulted in divergence among members of the
meso
-DAPDH family. A structure alignment of StDAPDH with a representative of type I, the
meso
-DAPDH from
Corynebacterium glutamicum
(CgDAPDH), indicated that they had the same folding. Based on sequence and conservation analyses, two amino acid residues of StDAPDH, R35 and R71, were found to be highly conserved within type II while also distinct from each other between the subtypes. Site mutagenesis studies identified R71 as a substrate preference-related residue of StDAPDH, which may serve as an indicator of the amination preference of type II. These results deepen the present understanding of the
meso
-DAPDH family and provide a solid foundation for the discovery and engineering of
meso
-DAPDH for
d
-amino acid biosynthesis.

IMPORTANCE
The
l
-form of amino acids is typically more abundant than the
d
-form. However, the
d
-form has many important pharmaceutical applications.
meso
-Diaminopimelate dehydrogenase (
meso
-DAPDH) from
Symbiobacterium thermophilum
(StDAPDH) was the first member of
meso
-DAPDH known to catalyze the amination of 2-keto acids to produce
d
-amino acids. Accordingly, we analyzed the evolution of
meso
-DAPDH proteins and found that they form two groups, i.e., type I proteins, which show high preference toward
meso
-diaminopimelate (
meso
-DAP), and type II proteins, which show a broad substrate spectrum. We examined the differences in sequence, ternary structure, and quaternary structure to determine the mechanisms underlying the functional differences between the type I and type II lineages. These results will facilitate the identification of additional
meso
-DAPDHs and may provide guidance to protein engineering studies for
d
-amino acid biosynthesis.
Enterobius vermicularis as a Novel Surrogate for the Presence of Helminth Ova in Tertiary Wastewater Treatment Plants
Authors: Rudko Sydney P. , Ruecker Norma J. , Ashbolt Nicholas J. , Neumann Norman F. , Hanington Patrick C.
Published: March 2017

Significant effort has gone into assessing the fate and removal of viruses, bacteria, and protozoan parasites during wastewater treatment to provide data addressing potential health risks associated with reuse options. Comparatively less is known about the fate of parasitic worm species ova in these complex systems. It is largely assumed that these helminths settle, are removed with the sludge, and consequently represent a relatively low risk for wastewater reuse applications. However, helminths are a highly diverse group of organisms that display a wide range of physical properties that complicate the application of a single treatment for helminth reduction during wastewater treatment. Moreover, their diverse biological and physical properties make some ova highly resistant to both disinfection (i.e., with chlorine or UV treatment) and physical removal (settling) through the wastewater treatment train, indicating that there may be reason to broaden the scope of our investigations into whether parasitic worm eggs can be identified in treated wastewater. The ubiquitous human parasitic nematode
Enterobius vermicularis
(pinworm) produces small, buoyant ova. Utilizing a novel diagnostic quantitative PCR (qPCR), this study monitored
E. vermicularis
presence at two full-scale wastewater treatment plants over the course of 8 months and demonstrated incomplete physical removal of
E. vermicularis
ova through tertiary treatment, with removal efficiencies approximating only 0.5 and 1.6 log
10
at the two wastewater treatment plants based on qPCR. These findings demonstrate the need for more-diverse surrogates of helminthic ova to fully assess treatment performance with respect to reclaimed wastewaters.

IMPORTANCE
Helminths, despite being a diverse and environmentally resistant class of pathogens, are often underestimated and ignored when treatment performance at modern wastewater treatment plants is considered. A one-size-fits-all surrogate for removal of helminth ova may be inappropriate to adequately assess risk and ensure public safety when treated and partially treated wastewaters are encountered. This study argues for the use of human pinworm as a conservative indicator of the presence of helminth ova due to its small size, buoyancy, prevalence in humans, and environmental resistance.
Recent Progress in the Prevention of Serogroup B Meningococcal Disease
Authors: Feavers Ian M. , Maiden Martin C. J.
Published: March 2017

The widespread use of meningococcal polysaccharide conjugate vaccines has highlighted the challenge of providing protection against serogroup B disease. Over a period of 4 decades, vaccine development has focused on subcapsular protein antigens, first with outer membrane vesicle (OMV) vaccines against epidemic outbreaks, and more recently on new multicomponent vaccines designed to offer better cross-protection against the antigenically diverse strains responsible for endemic disease. Because of the low incidence of meningococcal disease, the protective efficacy of these vaccines has not been determined in clinical studies, and their licensure has been based on serological data; however, the serological assays used to predict protective coverage have limitations. As a result, evidence of the effectiveness of these vaccines against different strains and the contribution of specific antigens to protection can only be provided by epidemiological analyses following their implementation in sufficiently large populations. The recent inclusion of the four-component meningococcal serogroup B (4CMenB) vaccine, Bexsero, in the infant immunization program in the UK has provided preliminary evidence that the vaccine is effective. Ongoing surveillance will provide valuable data on its longer-term impact and antigenic coverage. Further development of protein-based vaccines against meningococcal disease is anticipated to improve antigenic coverage and adjust to changes in circulating strains. At the same time, alternative immunization strategies may be explored to improve overall vaccine effectiveness by, for example, protecting the youngest infants or providing herd protection.
In Vitro
Antifungal Susceptibility of Yeast and Mold Phases of Isolates of Dimorphic Fungal Pathogen Emergomycesafricanus (Formerly Emmonsia sp.) from HIV-Infected South African Patients
Authors: Maphanga Tsidiso G. , Britz Erika , Zulu Thokozile G. , Mpembe Ruth S. , Naicker Serisha D. , Schwartz Ilan S. , Govender Nelesh P.
Published: March 2017

Disseminated emmonsiosis is an important AIDS-related mycosis in South Africa that is caused by
Emergomyces
africanus
, a newly described and renamed dimorphic fungal pathogen.
In vitro
antifungal susceptibility data can guide management. Identification of invasive clinical isolates was confirmed phenotypically and by sequencing of the internal transcribed spacer region. Yeast and mold phase MICs of fluconazole, voriconazole, itraconazole, posaconazole, caspofungin, anidulafungin, micafungin, and flucytosine were determined with custom-made frozen broth microdilution (BMD) panels in accordance with Clinical and Laboratory Standards Institute recommendations. MICs of amphotericin B, itraconazole, posaconazole, and voriconazole were determined by Etest. Fifty unique
E. africanus
isolates were tested. The yeast and mold phase geometric mean (GM) BMD and Etest MICs of itraconazole were 0.01 mg/liter. The voriconazole and posaconazole GM BMD MICs were 0.01 mg/liter for both phases, while the GM Etest MICs were 0.001 and 0.002 mg/liter, respectively. The fluconazole GM BMD MICs were 0.18 mg/liter for both phases. The GM Etest MICs of amphotericin B, for the yeast and mold phases were 0.03 and 0.01 mg/liter. The echinocandins and flucytosine had very limited
in vitro
activity. Treatment and outcome data were available for 37 patients; in a multivariable model including MIC data, only isolation from blood (odds ratio [OR], 8.6; 95% confidence interval [CI], 1.3 to 54.4;
P
= 0.02) or bone marrow (OR, 12.1; 95% CI, 1.2 to 120.2;
P
= 0.03) (versus skin biopsy) was associated with death.
In vitro
susceptibility data support the management of disseminated emmonsiosis with amphotericin B, followed by itraconazole, voriconazole, or posaconazole. Fluconazole was a relatively less potent agent.
Phosphatidylserine Lateral Organization Influences the Interaction of Influenza Virus Matrix Protein 1 with Lipid Membranes
Authors: Bobone Sara , Hilsch Malte , Storm Julian , Dunsing Valentin , Herrmann Andreas , Chiantia Salvatore
Published: March 2017

Influenza A virus matrix protein 1 (M1) is an essential component involved in the structural stability of the virus and in the budding of new virions from infected cells. A deeper understanding of the molecular basis of virion formation and the budding process is required in order to devise new therapeutic approaches. We performed a detailed investigation of the interaction between M1 and phosphatidylserine (PS) (i.e., its main binding target at the plasma membrane [PM]), as well as the distribution of PS itself, both in model membranes and in living cells. To this end, we used a combination of techniques, including Förster resonance energy transfer (FRET), confocal microscopy imaging, raster image correlation spectroscopy, and number and brightness (N&B) analysis. Our results show that PS can cluster in segregated regions in the plane of the lipid bilayer, both in model bilayers constituted of PS and phosphatidylcholine and in living cells. The viral protein M1 interacts specifically with PS-enriched domains, and such interaction in turn affects its oligomerization process. Furthermore, M1 can stabilize PS domains, as observed in model membranes. For living cells, the presence of PS clusters is suggested by N&B experiments monitoring the clustering of the PS sensor lactadherin. Also, colocalization between M1 and a fluorescent PS probe suggest that, in infected cells, the matrix protein can specifically bind to the regions of PM in which PS is clustered. Taken together, our observations provide novel evidence regarding the role of PS-rich domains in tuning M1-lipid and M1-M1 interactions at the PM of infected cells.

IMPORTANCE
Influenza virus particles assemble at the plasma membranes (PM) of infected cells. This process is orchestrated by the matrix protein M1, which interacts with membrane lipids while binding to the other proteins and genetic material of the virus. Despite its importance, the initial step in virus assembly (i.e., M1-lipid interaction) is still not well understood. In this work, we show that phosphatidylserine can form lipid domains in physical models of the inner leaflet of the PM. Furthermore, the spatial organization of PS in the plane of the bilayer modulates M1-M1 interactions. Finally, we show that PS domains appear to be present in the PM of living cells and that M1 seems to display a high affinity for them.
Mutual Interplay between the Human Cytomegalovirus Terminase Subunits pUL51, pUL56, and pUL89 Promotes Terminase Complex Formation
Authors: Neuber Sebastian , Wagner Karen , Goldner Thomas , Lischka Peter , Steinbrueck Lars , Messerle Martin , Borst Eva Maria
Published: March 2017

Human cytomegalovirus (HCMV) genome encapsidation requires several essential viral proteins, among them pUL56, pUL89, and the recently described pUL51, which constitute the viral terminase. To gain insight into terminase complex assembly, we investigated interactions between the individual subunits. For analysis in the viral context, HCMV bacterial artificial chromosomes carrying deletions in the open reading frames encoding the terminase proteins were used. These experiments were complemented by transient-transfection assays with plasmids expressing the terminase components. We found that if one terminase protein was missing, the levels of the other terminase proteins were markedly diminished, which could be overcome by proteasome inhibition or providing the missing subunit intrans. These data imply that sequestration of the individual subunits within the terminase complex protects them from proteasomal turnover. The finding that efficient interactions among the terminase proteins occurred only when all three were present together is reminiscent of a folding-upon-binding principle leading to cooperative stability. Furthermore, whereas pUL56 was translocated into the nucleus on its own, correct nuclear localization of pUL51 and pUL89 again required all three terminase constituents. Altogether, these features point to a model of the HCMV terminase as a multiprotein complex in which the three players regulate each other concerning stability, subcellular localization, and assembly into the functional tripartite holoenzyme.

IMPORTANCEHCMV is a major risk factor in immunocompromised individuals, and congenital CMV infection is the leading viral cause for long-term sequelae, including deafness and mental retardation. The current treatment of CMV disease is based on drugs sharing the same mechanism, namely, inhibiting viral DNA replication, and often results in adverse side effects and the appearance of resistant virus strains. Recently, the HCMV terminase has emerged as an auspicious target for novel antiviral drugs. A new drug candidate inhibiting the HCMV terminase, Letermovir, displayed excellent potency in clinical trials; however, its precise mode of action is not understood yet. Here, we describe the mutual dependence of the HCMV terminase constituents for their assembly into a functional terminase complex. Besides providing new basic insights into terminase formation, these results will be valuable when studying the mechanism of action for drugs targeting the HCMV terminase and developing additional substances interfering with viral genome encapsidation.
Chemokine Receptor Ccr7 Restricts Fatal West Nile Virus Encephalitis
Authors: Bardina Susana V. , Brown Julia A. , Michlmayr Daniela , Hoffman Kevin W. , Sum Janet , Pletnev Alexander G. , Lira Sergio A. , Lim Jean K.
Published: March 2017

West Nile virus (WNV) is a mosquito-transmitted flavivirus that can cause debilitating encephalitis. To delineate the mechanisms behind this pathology, we studied Ccr7-deficient mice, which afforded us the capacity to study infection in mice with disrupted peripheral cellular trafficking events. The loss of Ccr7 resulted in an immediate pan-leukocytosis that remained elevated throughout the infection. This leukocytosis resulted in a significant enhancement of leukocyte accumulation within the central nervous system (CNS). Despite an excess of virus-specific T cells in the CNS, Ccr7-deficient mice had significantly higher CNS viral loads and mortality rates than wild-type animals. Mechanistically, the elevated trafficking of infected myeloid cells into the brain in Ccr7-deficient mice resulted in increased levels of WNV in the CNS, thereby effectively contributing to neuroinflammation and lowering viral clearance. Combined, our experiments suggest that during WNV infection, Ccr7 is a gatekeeper for nonspecific viral transference to the brain.

IMPORTANCEIn this study, we show that Ccr7 is required for the sufficient migration of dendritic cells and T cells into the draining lymph node immediately following infection and for the restriction of leukocyte migration into the brain. Further, the severe loss of dendritic cells in the draining lymph node had no impact on viral replication in this organ, suggesting that WNV may migrate from the skin into the lymph node through another mechanism. Most importantly, we found that the loss of Ccr7 results in a significant leukocytosis, leading to hypercellularity within the CNS, where monocytes/macrophages contribute to CNS viremia, neuroinflammation, and increased mortality. Together, our data point to Ccr7 as a critical host defense restriction factor limiting neuroinflammation during acute viral infection.
De Garengeot's hernia: an unusual case on call
Authors: Moore Madeline , Amr Bassem
Published: March 2017

De Garengeot's hernia is defined as a femoral hernia that contains the appendix. Owing to the extreme rarity of de Garengeot's hernia, it could represent a diagnostic challenge; however, it should remain in the differential diagnosis, particularly in this patient demographic. A female patient aged 96 years, who presented as an emergency with acute right iliac fossa pain, was found to have de Garengeot's hernia. The diagnosis was made intraoperatively, where she was treated with an appendicectomy and repair of the hernia defect. The incidence of de Garengeot's hernia is 0.5–5% and the incidence of appendicitis within a femoral hernia is extremely rare. Preoperative diagnosis is challenging to the treating surgeon, which requires a high index of suspicion and is usually made intraoperatively. There is no standard treatment; however, simple appendicectomy and hernia repair seems to be an accepted management.
Safety and efficacy of saxagliptin for glycemic control in non-critically ill hospitalized patients
Authors: Garg Rajesh , Schuman Brooke , Hurwitz Shelley , Metzger Cheyenne , Bhandari Shreya
Published: March 2017

Objective

To evaluate whether saxagliptin is non-inferior to basal-bolus insulin therapy for glycemic control in patients with controlled type 2 diabetes mellitus (T2DM) admitted to hospital with non-critical illnesses.

Research design and methods

This was an open-label, randomized controlled clinical trial. Patients received either saxagliptin or basal-bolus insulin, both with correctional insulin doses. The main study outcome was the mean daily blood glucose (BG) after the first day of randomization.

Results

Of 66 patients completing the study, 33 (age 69±10 years, 40% men) were randomized to saxagliptin and 33 (age 67±10 years, 52% men) to basal-bolus insulin therapy. The mean daily BG was 149.8±22.0 mg/dL in the saxagliptin group and 146.9±30.5 mg/dL in the insulin group (p=0.59). With an observed group difference of 2.9 mg/dL and an a priori margin of 20 mg/dL, inferiority of saxagliptin was rejected in favor of non-inferiority (p=0.007). There was no significant difference in the percentage of high or low BG values. The insulin group received a higher number of insulin injections (2.3±1.7/day vs 1.2±1.9/day; p<0.001) as well as a higher daily insulin dose (13.3±12.9 units/day vs 2.4±3.3 units/day; p<0.001) than did the saxagliptin group. Continuous BG monitoring showed that glycemic variability was lower in the saxagliptin group as compared to the insulin group. Patient satisfaction scores were similar in the two groups.

Conclusions

We conclude that saxagliptin use is non-inferior to basal-bolus insulin in non-critically ill hospitalized patients with T2DM controlled on 0–2 oral agents without insulin. Saxagliptin use may decrease glycemic variability in these patients.

Trial registration number

NCT02182895.
Quality assurance of medicines supplied to low-income and middle-income countries: poor products in shiny boxes?
Authors: Nebot Giralt A , Schiavetti B , Meessen B , Pouget C , Caudron J M , Marchal B , Massat P , Thys S , Ravinetto R
Published: March 2017

Objective

In today's context of globalisation of pharmaceutical production and distribution, international and national procurement agencies play a de facto key role in defining the quality of medicines available in sub-Saharan Africa. We evaluated the compliance of a sample of pharmaceutical distributors active in sub-Saharan Africa with the standards of the WHO guideline ‘Model Quality Assurance System (WHO MQAS) for procurement agencies’, and we investigated factors favouring or hindering the adequate implementation of the guideline.

Methods

We used mixed-methods methodology to analyse quantitative and qualitative data. The quantitative study consisted of a retrospective secondary analysis of data collected by QUAMED (Quality Medicines for all), a partnership that pleads for universal access to quality-assured medicines. The qualitative survey consisted of formal and informal interviews with key informants. We adopted an embedded multiple-case study design.

Findings

Our analysis suggests that international distributors based in Europe perform, on average, better than sub-Saharan African distributors. However, some weaknesses are ubiquitous and concern critical processes, such as the initial selection of the products and the ongoing reassessment of their quality. This is due to several different factors: weak regulatory oversight, insufficient human/financial resources, weak negotiating power, limited judicial autonomy and/or lack of institutional commitment to quality.

Conclusions

Our findings suggest that pharmaceutical distributors active in sub-Saharan Africa generally do not apply stringent criteria for selecting products and suppliers. Therefore, product quality is not consistently assured but depends on the requirements of purchasers. While long-term solutions are awaited, the WHO MQAS guideline should be used as an evaluation and training tool to upgrade current standards.
Instability analysis of expansion-free sphere in f(𝒢) gravity
Authors: Sharif M. , Ikram Ayesha
Published: March 2017

The aim of this paper is to study the dynamical instability of expansion-free spherically symmetric anisotropic fluid in the framework of [Formula: see text] gravity. We apply perturbation scheme of the first-order to the metric functions as well as matter variables and construct modified field equations for both static and perturbed configurations using power-law [Formula: see text] model. To discuss the instability dynamics, we use the contracted Bianchi identities to formulate the dynamical equations in both Newtonian and post-Newtonian regimes. It is found that the range of instability is independent of adiabatic index for expansion-free fluid but depends on anisotropic pressures, energy density and Gauss–Bonnet (GB) terms.
ON THE CALCULATION OF RISK MEASURES USING LEAST-SQUARES MONTE CARLO
Authors: BENEDETTI GIUSEPPE
Published: March 2017

The paper establishes a convergence result for the Least-Squares Monte Carlo method, applied to the estimation of risk measures (such as VaR) depending on the distribution of the future value of some derivative contract (or portfolio). We extend previous results in the literature by focusing on the specific case where the distribution of the underlying factors is known. In particular, we are able to remove the requirement of bounded conditional variance which is usually not satisfied by common financial models and payoffs at the cost of using a weaker notion of convergence. Our main result shows the convergence of the empirical distribution function when the number of simulations [Formula: see text] and of basis variables [Formula: see text] are jointly sent to infinity under certain conditions on the payoff and the basis. With a suitable choice of basis functions, we finally prove that convergence can be ensured when [Formula: see text].
Analysis of microseismic events during a multistage hydraulic stimulation experiment at a shale gas reservoir
Authors: Kaka SanLinn I. , Reyes-Montes Juan M. , Al-Shuhail Abdullah , Al-Shuhail Abdullatif A. , Jervis Michael
Published: March 2017

Despite the current easing in demand for increased oil production linked to the global downturn in crude prices, energy demand continuously increases and the long-term demand will require maximizing the productivity of reservoirs and a search into the exploitation of new resources in increasingly challenging environments. In this study, we present the results from the monitoring of the very first multistage stimulation experiment at a shale gas reservoir in Saudi Arabia, presenting an analysis of the microseismicity induced during the treatment. Our aim was to analyse microseismic events to better understand fracture growth and the role of pre-existing fractures in these reservoirs. Microseismic (MS) event monitoring is used to track the creation of fractures during and after the stimulation, and therefore to evaluate the effect of the reservoir stimulation. The monitoring includes a downhole array of 12 3C-sensors that were deployed in a vertical well with a 30.5 m level spacing. A total of 415 MS events were located and analysed, with the results outlining induced fractures extending consistently with an average azimuth of N335° E, normal to the horizontal section of the treatment well. This implies that there are no changes in the local stress direction along the treatment well either
in situ
or induced along the treatment. There are significant changes in total length and aspect ratio (length/width) of the fractures induced in the different stages. These variations could be attributed to
in situ
fracturing, local rock heterogeneity or the influence of the treatment parameters. In general, early and late stages of stimulation show the longest fracture networks, with events induced further away from the initiation point. We found no immediate relationship between treatment parameters (peak pressure and pumping rates) and fracture extension. Sensitivity analysis using Monte Carlo simulation methods shows a higher location uncertainty for events located at the early stages, thus limiting the interpretation from monitored seismicity in the early stages. An analysis of magnitude distribution with distance shows a decrease in sensitivity of one degree of magnitude for every 375 m, and a maximum viewing distance of approximately 700 m for the current set-up. The low number of located events does not provide a complete enough dataset for a robust analysis of changes in
b
-value (slope in linear part of magnitude distribution) during the treatment: however, magnitude distributions, corrected for array sensitivity, provide a useful variable for the validation of geomechanical models currently being developed for the reservoir.
Geomaterials: aggregates, building stone and earthworks: papers from 50 years of QJEGH
Authors: Cassar J. , Standing J. R.
Published: March 2017

Numerous papers included within the broad subject of geomaterials have been published in QJEGH over the past 50 years. These have been compiled and divided here into three main categories: aggregates, building stone and earthworks. The aim of this review is to provide a comprehensive summary of the relevant papers published in QJEGH with a view to identifying the main areas of interest historically, now and in the future. Some clear trends are evident from the survey and review; for example, there has been a steady interest in building stone and in particular its deterioration, a decline in papers on earthworks and an increase in those on ground improvement (also covered here). It is also noted that methods of characterizing geomaterials are becoming more sophisticated with advancing technology. The review makes relevant links with other Special Publications from the Geological Society, including also Engineering Geology Special Publications.
Primary Spontaneous Pneumothorax Admitted in Emergency Unit: Does First Episode Differ from Recurrence? A Cross-Sectional Study
Authors: Kepka S. , Dalphin J. C. , Parmentier A. L. , Pretalli J. B. , Gantelet M. , Bernard N. , Mauny F. , Desmettre T.
Published: March 2017

Introduction. Management of primary spontaneous pneumothorax (PSP) consists of immediate resolution of pleural air, or observation, and prevention of recurrence. The risk factors for recurrence remain debated.Objectives. We aimed to describe and compare the characteristics of patients presenting a first episode of PSP to those of patients presenting a recurrent PSP, in order to identify factors potentially related to recurrence.Methods. We conducted a cross-sectional study including all admissions for PSP in the EDs of fourteen French public hospitals from 2009 to 2013. PSP were classified as a first episode if the patient had no previous history of pneumothorax and as recurrence if a previous episode of spontaneous pneumothorax was documented in the patient’s medical records or if a recurrence was identified during the inclusion period. To identify factors potentially associated with recurrence of PSP, multilevel logistic models were fitted.Results. During the study period, 918 (61,6%) first episodes and 573 (38,4%) episodes of recurrent PSP were identified. Clinical presentation, age, gender, smoking habits, and use of cannabis were similar in both groups. No clinical factor associated with recurrence was identified by multivariate analysis.Conclusion. In this large multicenter study, no clinical factor associated with recurrence was highlighted.
Transmesenteric Internal Herniation Leading to Small Bowel Obstruction Postlaparoscopic Radical Nephrectomy
Authors: Cuthbert G. A. , Teo L. T.
Published: March 2017

Internal herniation following laparoscopic surgery is rare. We present a case of small bowel obstruction secondary to internal herniation in a 76-year-old male patient. Presentation was on postoperative day 28 following transperitoneal laparoscopic radical left nephrectomy for suspected renal carcinoma. The herniation was through a defect in the large bowel mesentery identified at exploratory laparotomy. To date, 10 cases of internal herniation following laparoscopic nephrectomy have been described in the literature. Two cases were managed laparoscopically and the remainder by laparotomy. One case required resection of an ischaemic portion small bowel and the remainder were managed by reduction of the hernia and closure of the defect. Internal herniation is rare but carries significant morbidity. It must be considered in cases presenting with obstructive symptoms after laparoscopic nephrectomy. Early CT scanning and prompt surgical management are hallmarks of best management.
Preoperative Inflammatory Control and Surgical Outcome of Vitrectomy in Intermediate Uveitis
Authors: Shin Yong Un , Shin Joo Young , Ma Dae Joong , Cho Heeyoon , Yu Hyeong Gon
Published: March 2017

Purpose. To demonstrate the long-term effectiveness of vitrectomy for intermediate uveitis (IU) and to determine whether complete control of inflammation before vitrectomy is necessary.Methods. This retrospective study included 66 eyes of 66 patients with IU who underwent vitrectomy for vitreoretinal complications. Eyes were followed for at least 12 months after vitrectomy. The degree of inflammation control and visual acuity were compared before and after vitrectomy. These parameters were compared according to the presence of complete inflammation control before surgery.Results. The indications of vitrectomy included epiretinal membrane (26 eyes), vitreous opacity (21 eyes), and tractional retinal detachment (12 eyes), among others. Uveitic attacks did not occur in 44 of the 66 patients after vitrectomy. The numbers of uveitis attacks, local steroid injections, and systemic medications significantly decreased, and vision meaningfully improved after vitrectomy. These parameters did not differ significantly, regardless of the presence of preoperative inflammation.Conclusions. This study showed that vitrectomy is a good modality to manage vitreoretinal complications associated with IU, even if complete control of intraocular inflammation is not achieved before vitrectomy.
The Effect of Fermented Lingonberry Juice onCandida glabrataIntracellular Protein Expression
Authors: Pärnänen Pirjo , Nawaz Ali , Sorsa Timo , Meurman Jukka , Nikula-Ijäs Pirjo
Published: March 2017

Lingonberries have a long traditional use in treating fungal infections on mucosal membranes, but very little is known about the exact antifungal mechanisms. We tested the effects of fermented lingonberry juice onCandida glabrataintracellular protein expression. ACandida glabrataclinical strain was grown in the presence of fermented lingonberry juice (FLJ). Also the effect of lowered pH was tested. Intracellular protein expression levels were analyzed by the 2D-DIGE method. Six proteins detected with ≥1.5-fold lowered expression levels from FLJ treated cells were further characterized with LC-MS/MS. Heat shock protein 9/12 and redoxin were identified with peptide coverage/scores of 68/129 and 21/26, respectively. Heat shock protein 9/12 had an oxidized methionine at position 56. We found no differences in protein expression levels at pH 3.5 compared to pH 7.6. These results demonstrate that FLJ exerts an intracellular stress response inCandida glabrata, plausibly impairing its ability to express proteins related to oxidative stress or maintaining cell wall integrity.
Traditional Chinese Herbs Improve Salivation and Frequent Nighttime Urination in Patients with Amyotrophic Lateral Sclerosis
Authors: Gao Penglin , Liao Weilong , Sun Chuanhe , Jiang Wenfei , Pan Weidong , Liu Te
Published: March 2017

Aims: The aim of this study was to explore the efficacy of Jian-Pi Lian-Se Tang (JPLST), a formula of traditional Chinese medicine for the treatment of salivation and frequent nighttime urination (FNU) in patients with amyotrophic lateral sclerosis (ALS). Method: Forty-eight patients with ALS suffering from salivation and/or FNU who were outpatients or inpatients of Shuguang Hospital were included into the study and divided into 2 groups as follows: the JPLST group (n = 24) included patients who were additionally treated with JPLST, and the control group (n = 24) included patients who were treated by routine Western medicine (for 6 weeks). The changes in the quantity of salivation/sialorrhea (QS) (in mL) and in FNU as the primary result and the total scores of the Amyloid Lateral Sclerosis Function Rating Scale (ALSFRS) and of the Epworth Sleepiness Scale (ESS) as the secondary result were used to evaluate the clinical efficacy for both groups. Results: No significant differences were found for the baseline of QS, FNU, and the scores of the ESS and of the ALSFRS before and after treatment for both groups. At the end of the 6th week, 2 patients in the JPLST group and 4 patients in the control group withdrew from the study. QS and FNU were much less severe in the JPLST group than before treatment, and the ESS scores were improved, too. The ALSFRS did not show any significant differences in both groups compared with before treatment at the end of week 6. No side effects were found for both groups by laboratory tests. Conclusion: The much improved parameters of QS, FNU, and ESS for the JPLST group indicate that JPLST may be a potential additional treatment for salivation and FNU in ALS patients. Large-scale multicenter double-blind randomized-control studies are needed to verify the effectiveness of JPLST in improving salivation and FNU in patients with ALS.
Triggering of Suicidal Erythrocyte Death by Gefitinib
Authors: Al Mamun Bhuyan Abdulla , Wagner Teresa , Cao Hang , Lang Florian
Published: March 2017

Background/Aims: The epidermal growth factor receptor-tyrosine kinase inhibitor gefitinib is effective against several malignancies and is mainly utilized in the treatment of epidermal growth factor receptor mutation positive non-small cell lung cancer. The anti-cancer effect of the drug involves stimulation of apoptosis. Side effects of gefitinib include anemia. At least in theory, the development of anemia during gefitinib treatment could result from triggering of eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling potentially stimulating eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i) and generation of oxidative stress. The present study explored, whether gefitinib stimulates eryptosis and, if so, whether its effect involves Ca2+ entry and/or oxidative stress. Methods: Flow cytometry was employed to quantify cell volume from forward scatter, phosphatidylserine exposure at the cell surface from annexin-V-binding, [Ca2+]i from Fluo3-fluorescence, and reactive oxygen species (ROS) abundance from 2’,7’-dichlorodihydrofluorescein diacetate (DCFDA) dependent fluorescence. Results: A 48 hours exposure of human erythrocytes to gefitinib (≥ 2 µg/ml) significantly decreased forward scatter and significantly increased the percentage of annexin-V-binding cells. Gefitinib did not significantly increase Fluo3-fluorescence but the effect of gefitinib on annexin-V-binding was significantly blunted by removal of extracellular Ca2+. Gefitinib further significantly increased DCFDA fluorescence. Conclusions: Gefitinib triggers erythrocyte shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part dependent on extracellular Ca2+ and paralleled by oxidative stress.
Redes de bibliotecas escolares no Brasil: estudos de caso em sistemas municipais de ensino
Authors: Limas Rubeniki Fernandes de , Campello Bernadete Santos
Published: March 2017

O objetivo da pesquisa foi compreender o funcionamento de redes de bibliotecas escolares sob aspectos estratégicos. Os procedimentos metodológicos foram qualitativos. Utilizou-se estudo de casos múltiplos, com amostra de três redes em funcionamento. A coleta de dados foi feita por meio de pesquisa documental e entrevistas com coordenadores de redes. Os resultados demonstram que o diferencial das redes analisadas, ainda que se identifiquem problemas a serem superados, encontram-se na maior consolidação de aspectos como: concepção de biblioteca, apoio em legislação, dotação orçamentária, existência na estrutura administrativa, profissionalização e inserção em políticas públicas. Conclui que as redes representam um movimento de “setorização” e profissionalização da biblioteca escolar. Espera-se que os resultados possibilitem uma compreensão mais ampla do panorama atual, além de servir de base para estudos mais aprofundados em alguns pontos ou mesmo inspirar a modelagem de novas redes de bibliotecas.
Política de Indexação: um estudo nas Bibliotecas Públicas do Estado do Rio de Janeiro
Authors: Andrade Mariana Acorse Lins de , Sabbag Deise Maria Antonio
Published: March 2017

O trabalho apresenta e define as Bibliotecas Públicas do Estado do Rio de Janeiro e as Bibliotecas Parque. Define a Indexação e apresenta seu histórico. Descreve a Política de Indexação e mostra sua importância. Identifica e analisa os fatores existentes para o planejamento dentro do sistema de informação, com base nos autores Carneiro (1985), Foskett (1973) e Rubi (2004). Identifica e analisa os elementos que devem ser considerados ao se elaborar uma Política de Indexação, com base nos autores Carneiro (1985), Foskett (1973) e Rubi (2004). Investiga a Política de Indexação nas Bibliotecas Públicas do Estado do Rio de Janeiro.
Fractional Flow Reserve and Cardiac Events in Coronary Artery Disease
Authors: Ahn Jung-Min , Park Duk-Woo , Shin Eun-Seok , Koo Bon-Kwon , Nam Chang-Wook , Doh Joon-Hyung , Kim Jun Hong , Chae In-Ho , Yoon Jung-Han , Her Sung-Ho , Seung Ki-Bae , Chung Woo-Young , Yoo Sang-Yong , Lee Jin Bae , Choi Si Wan , Park Kyungil , Hong Taek Jong , Lee Sang Yeub , Han Minkyu , Lee Pil Hyung , Kang Soo-Jin , Lee Seung-Whan , Kim Young-Hak , Lee Cheol Whan , Park Seong-Wook , Park Seung-Jung
Published: March 2017

Background:

We evaluated the prognosis of deferred and revascularized coronary stenoses after fractional flow reserve (FFR) measurement to assess its revascularization threshold in clinical practice.

Methods:

The IRIS-FFR registry (Interventional Cardiology Research In-cooperation Society Fractional Flow Reserve) prospectively enrolled 5846 patients with ≥1coronary lesion with FFR measurement. Revascularization was deferred in 6468 lesions and performed in 2165 lesions after FFR assessment. The primary end point was major adverse cardiac events (cardiac death, myocardial infarction, and repeat revascularization) at a median follow-up of 1.9 years and analyzed on a per-lesion basis. A marginal Cox model accounted for correlated data in patients with multiple lesions, and a model to predict per-lesion outcomes was adjusted for confounding factors.

Results:

For deferred lesions, the risk of major adverse cardiac events demonstrated a significant, inverse relationship with FFR (adjusted hazard ratio, 1.06; 95% confidence interval, 1.05–1.08;
P
<0.001). However, this relationship was not observed in revascularized lesions (adjusted hazard ratio, 1.00; 95% confidence interval, 0.98–1.02;
P
=0.70). For lesions with FFR ≥0.76, the risk of major adverse cardiac events was not significantly different between deferred and revascularized lesions. Conversely, in lesions with FFR ≤0.75, the risk of major adverse cardiac events was significantly lower in revascularized lesions than in deferred lesions (for FFR 0.71–0.75, adjusted hazard ratio, 0.47; 95% confidence interval, 0.24–0.89;
P
=0.021; for FFR ≤0.70, adjusted hazard ratio 0.47; 95% confidence interval, 0.26–0.84;
P
=0.012).

Conclusions:

This large, prospective registry showed that the FFR value was linearly associated with the risk of cardiac events in deferred lesions. In addition, revascularization for coronary artery stenosis with a low FFR (≤0.75) was associated with better outcomes than the deferral, whereas for a stenosis with a high FFR (≥0.76), medical treatment would be a reasonable and safe treatment strategy.

Clinical Trial Registration:

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT01366404.