bluuebunny/crossref_metadata_2025 huggingface dataset:
Calibration and Validation of a Wide Range Segmented Gamma Ray Scanning Instrument for the Measurement of Low and Intermediate Level Waste
Authors: Mason John A. , Looman Marc R. , Towner Antony C. N. , Fernando Kapila , Wong Roland , Price Robert A. , Taylor Brett , Anderson Paul
Published: August 2012

This paper describes the design and calibration of a Wide Range Segmented Gamma ray Scanning (WR-SGS) assay instrument for the measurement of both Low and Intermediate Level Waste (LLW and ILW) in 200 litre drums. The instrument employs a single shielded and collimated high purity germanium (HPGe) detector to quantify the radionuclide content of the waste. One of the novel features of the instrument is the use of an automated variable aperture collimator, which allows the vertical segment height to be adjusted, and allows the scanning of intermediate level waste drums, with significant surface dose rates. Conventional SGS measurements may be performed where the drum is rotated and measured in vertical segments. Alternatively, faster measurement can be made using continuous helical scanning of the drum as it rotates. A gamma ray emitting transmission source is used to correct for waste density. In place of a conventional shutter, the shielded transmission source is moved to a shielded storage position to eliminate background radiation arising from the transmission source. Using this approach, higher activity transmission sources may be used in order to achieve adequate density corrections for higher density drums. These new features makes the WR-SGS suitable for the measurement of drums containing exempt level waste to intermediate level waste, as well as drums with a wide range of density. Results will be presented from the calibration of the instrument using horizontally displaced line sources to simulate distributed sources and the results will be compared with benchmarked MCNP Monte Carlo calculations.
Update on Jose´ Cabrera NPP Decommissioning
Authors: Marti´n Nieves , Rodri´guez Manuel
Published: August 2012

ENRESA is the National Spanish Agency responsible of the dismantling of Nuclear Facilities, previous Transfer of ownership of the facility from the Utility to ENRESA. On April 30th 2006, Jose´ Cabrera Nuclear Power Plant (Fig. 1) was definitively shutdown, and two years later, on April 30th 2008, ENRESA requested the transfer of the ownership of the Plant from the Ministry along with the corresponding authorization for performance of the Dismantling and Decommissioning Plan. On February 1st 2010, ENRESA was authorized to initiate the dismantling of Jose´ Cabrera NPP, once the spent fuel has been stored on-site at a dry storage facility (ISFSI). Currently, preparatory activities are underway, including the modification of systems and auxiliary facilities for waste and material management. Main challenges of the project include the removal of major components (vessel, steam generator, pressurizer, main pump and primary loop), and the use of large containers (CE-2b) to reduce segmentation of activated parts.
Outreach and Education to Ensure a Clean Energy Future for All
Authors: Hess Susan M.
Published: August 2012

As the nuclear industry continues to grow throughout the world, we find that support from government officials, local business leaders and the general public is becoming more and more important. In order to help raise awareness and inform these various publics, AREVA expanded upon a best practice from its worldwide operations and recently established a Community Advisory Council in the United States. The member organizations represent a variety of grassroots and minority organizations from across the United States and are active in various ways in local, state and federal arenas. AREVA’s objective for the Council is simple — listen to concerns, engage in dialogue and raise awareness about the intrinsic link existing between energy, CO2 emissions, global warming, and economic growth, so these same people can make decisions when it comes to energy sources in the future. We want our members to help us better understand their communities, listen to their concerns and answer their questions openly and honestly. AREVA understands that this outreach and education are just the first steps toward helping clean energy sources grow. We must maintain regular dialog and operate in a safe manner, because in the long run, it is these community members who will ensure energy security for the country. And it is only by working together as an industry that we can ensure a safe, clean air future for generations to come, no matter where in the world we live.
A New Safety Concept for Geological Disposal in Japan (II)
Authors: Kitayama Kazumi
Published: August 2012

This paper provides further discussion of a new defence-in-depth safety concept that was presented at ICEM09[1]. The basic idea is that it is rational to assume that the performance of passive engineered barriers with suitably chosen characteristics and the natural barrier will maintain their safety functions for a sufficiently long time due to geochemical buffering occurring deep underground, The approach can be used to enhance and embed public understanding of the long-term safety of geological disposal. This paper summarizes the logic of the approach focusing on the following topics, which are the basic themes of the new safety concept. 1. Applicability of the defence-in-depth concept to the geological disposal of radioactive waste; 2. Natural Analogue approach to explaining the long-term behaviour of the barriers; and 3. Approach for the Social Dialogue with stakeholder, which is the most important issue for site selection.
The Assessment of the Waste Management Plan to Decommissioning of Cernavoda NPP for Environmental Impact Reduction
Authors: Barariu Gheorghe
Published: August 2012

Most of the radioactive wastes generated in Romania, are due to nuclear activities related to power generation at Cernavoda Nuclear Power Plant NPP Unit 1 and Unit 2. It is provided to construct 2 new Units, in the next period. In Romania, the Nuclear Agency & Radioactive Waste - AN&DR, has established the strategy on low and intermediate level waste disposal and has as objective the commissioning of Final Repository for Low and Intermediate Level Waste – DFDSMA, until 2019. This facility, is in the responsibility of AN&DR. On the other hand, wastes arising from Cernavoda NPP must be treated, in order to achieve the acceptance criteria of DFDSMA. Corresponding Radioactive Waste Treatment Plant - RWTP is in the responsibility of Cernavoda NPP. The main requirement for the RWTP is the necessity to achieve the treatment and conditioning of radioactive wastes that arise both, from NPP operation and from future decommissioning activities of the nuclear facilities, such as to comply with the acceptance criteria of DFDSMA. According to existing requirements, it is necessary to elaborate a Decommissioning Plan, in order to obtain the authorization for construction of the new units. The Decommissioning Plan of Cernavoda NPP will imply the development of a Waste Management Plan, based on existing waste treatment technologies. Taking into account that, the radioactive waste management represents about 43%, comparative with decommissioning activities, which represents only about 35% from total budget of decommissioning, of a CANDU 6 NPP Unit, the paper will present the methodology developed, in order to obtain the optimum Waste Management Plan, taking into account the reduction of environmental impact.
Decommissioning and Dismantling of the French Brennilis NPP
Authors: Andre´ Thierry , Botzem Werner
Published: August 2012

This paper deals with the dismantling of the Brennilis NPP plant located in the west of France (Finiste`re). This prototype NPP of Brennilis was the unique reactor of the heavy water developed in France during the 50’ and the 60’. The reactor diverged in December 1966 and the NPP was operated during 9 years from 1972 to 1981, then the permanent shutdown occurred in July 1985. In 2008, the operator and owner of the plant Electricite´ de France (EDF) commissioned the consortium Onet Technologies Grands Projets (France) and Nukem Technologies (Germany) with the dismantling of the reactor block of the NPP. The reactor block essentially contains the reactor vessel including built-in units and biological shields, the peripheral piping as well as systems for controlling the nuclear-related process. In addition to the complete dismantling, the scope of the contractual services also includes their proper handling in accordance with the applicable regulation: safety requirements, waste management, radioprotection optimization and management. The central element of the plant is the reactor pressure vessel filled with heavy water. Each of the 216 horizontal fuel element channels made of zircaloy is at each side connected to a pipe which directs the heat transfer gas to a header mounted in the upper part of the reactor block. The control rods are introduced vertically into the reactor. It should be pointed out that due to this reactor design, the reactor pressure vessel is equipped with a complex pipe system to all sides which makes it difficult to freely access the core area of the reactor block and thus to dismantle the reactor. In this context, the axial and lateral neutron shields should be mentioned, which are situated in close proximity to the reactor as well as the biological shield which protects from ionizing radiation originating from the pressure vessel. The access to the core area is made difficult due to a high local dose rate and the extremely high constructive complexity of the prototype, the interior of which is virtually criss-crossed by complex piping. The elevated local dose rate in the area of the reactor pressure vessel makes manual work in this zone impossible (even after 30 years), so that remote dismantling techniques have to be used. Before starting dismantling, the remote devices are determined with the help of a test stand which representatively simulates the real conditions of the reactor block in respect to dimensions and material.
Application of the Data Quality Objective Process to the Partial De-Licensing at Oldbury Nuclear Power Station
Authors: Buckley Denis
Published: August 2012

Early in 2011 Oldbury Nuclear Power station in South West England applied to the Office of Nuclear Regulation (ONR) to de-license an area of over 30 hectares of licensed land. This is the largest area of licensed land in the UK to undergo this procedure. As part of the process the site prepared a safety case to support the submission to the ONR. Also there has been a requirement to do sampling and analysis to characterise the land and show that any radioactive contamination is below the criterion for de-licensing. This has been achieved through the successful application of the Data Quality Objective (DQO) process which enabled both site and regulators to agree on the quantity of samples and the degree of analysis. The ONR has now issued the variation to Oldbury in July 2011 de-licensing approximately 32 hectares of land from regulatory control. This Paper outlines the process including the decisions and criteria that have been applied to the Sampling and Analysis at Oldbury and the Treatment and Interpretation of the data.
Dismantling of Civilian Nuclear Powered Fleet Technical Support Vessels: Engineering Solutions
Authors: Kulikov Konstantin N. , Nizamutdinov Rinat A. , Abramov Andrey N.
Published: August 2012

At the present time six nuclear technical support vessels are operated and maintained by Atomflot. Two of them (Volodarsky FTB (floating technical base) and Lepse FTB) were taken out of service for decommissioning and are stored afloat. One more vessel Lotta FTB should be decommissioned during next two years. The nuclear technological support ships carrying spent nuclear fuel (SNF), liquid and solid radioactive wastes (LRW and SRW) appear to be a possible radiation contamination of Murmansk region and Kola Bay because the Ship long-term storage afloat has the negative effect on hull’s structures technical condition. As a result of this in the context of the Federal Program “Nuclear and Radiation Safety” (2008–2015) NIPTB Onega OAO was engaged by state corporation Rosatom to develop the dismantling procedure for Volodarsky FTB and Lotta FTB. Before developing of nuclear technological support ships decommissioning projects the technical and economic assessment of decommissioning/dismantling was carried out. The following options were examined: - formation of module as one-piece Ship’s hull for long-term storage at Saida Bay; - formation of separated modules for long-term storage at Saida Bay; - complete dismantling of hull’s structures, systems and equipment with packing all generated SRW into certified long-term storage containers. This paper contains description of options, research procedure, comparative analysis of options of decommissioning and dismantling (D&D) of nuclear technological support ships and its difference with dismantling of nuclear submarine.
Application of a New Technology for Reprocessing of Wastes Within the Framework of Rehabilitation of Uranium Mines Operated by In Situ Leaching
Authors: Martoyan Gagik , Nalbandyan Garik , Gagiyan Lavrenti , Karamyan Gagik , Barseghyan Artak , Brutyan Gagik
Published: August 2012

It is essential the environmentally safe industrial production of nuclear fuel especially in the case of uranium extraction by In Situ Leaching, when the environment and the deep extraction of uranium are important problems. In the presented paper it is studied the feasibility of the application of an electrodialysis method for the deep extraction of uranium and radium from liquid (acid) streams. It is proposed to apply a new electro-hydro-metallurgical [1] extraction and refining method to ensure the necessary extraction level of elements. In the same time the new method ensures the recycling of acids used in the process.
Regulatory Clearance of Spent Steel Drums
Authors: Hong Dae-Seok , Ji Yong-Yong , Kang Il-Sik , Kwak Kyoung-Kil , Ryu Woo-Seog
Published: August 2012

At KAERI (Korea Atomic Energy Institute), radioactive soil and concrete wastes with extremely low level of activity were regulatory cleared in 2008 and large amount of spent drums remained. After generation, drums having good physical integrity reused for packaging radioactive wastes and about 50 tons of drums unsuitable for reuse were stored as radioactive wastes. Having once been used for packaging regulatory cleared radioactive wastes, these spent drums were determined to be regulatory cleared. Before regulatory clearance, steel drums were radiation monitored, washed with pressurized water two times, compacted and stored at a designated area. Based on radiological dose assessment results using a recycling scenario derived from actual situation, the regulatory clearance of steel drums was permitted by the regulatory body. Treatment of the regulatory cleared drums was then committed to a scrap-metal dealer for recycling. In this study, a process of regulatory clearance for spent steel drums and a modified radiological dose assessment model for staff members of a scrap-metal dealer will be discussed.
Characterization of adaptive statistical iterative reconstruction algorithm for dose reduction in CT: A pediatric oncology perspective
Authors: Brady S. L. , Yee B. S. , Kaufman R. A.
Published: August 2012

Purpose:

This study demonstrates a means of implementing an adaptive statistical iterative reconstruction (ASiR™) technique for dose reduction in computed tomography (CT) while maintaining similar noise levels in the reconstructed image. The effects of image quality and noise texture were assessed at all implementation levels of ASiR™. Empirically derived dose reduction limits were established for ASiR™ for imaging of the trunk for a pediatric oncology population ranging from 1 yr old through adolescence/adulthood.

Methods:

Image quality was assessed using metrics established by the American College of Radiology (ACR) CT accreditation program. Each image quality metric was tested using the ACR CT phantom with 0%–100% ASiR™ blended with filtered back projection (FBP) reconstructed images. Additionally, the noise power spectrum (NPS) was calculated for three common reconstruction filters of the trunk. The empirically derived limitations on ASiR™ implementation for dose reduction were assessed using (1, 5, 10) yr old and adolescent/adult anthropomorphic phantoms. To assess dose reduction limits, the phantoms were scanned in increments of increased noise index (decrementing mA using automatic tube current modulation) balanced with ASiR™ reconstruction to maintain noise equivalence of the 0% ASiR™ image.

Results:

The ASiR™ algorithm did not produce any unfavorable effects on image quality as assessed by ACR criteria. Conversely, low‐contrast resolution was found to improve due to the reduction of noise in the reconstructed images. NPS calculations demonstrated that images with lower frequency noise had lower noise variance and coarser graininess at progressively higher percentages of ASiR™ reconstruction; and in spite of the similar magnitudes of noise, the image reconstructed with 50% or more ASiR™ presented a more smoothed appearance than the pre‐ASiR™ 100% FBP image. Finally, relative to non‐ASiR™ images with 100% of standard dose across the pediatric phantom age spectrum, similar noise levels were obtained in the images at a dose reduction of 48% with 40% ASIR™ and a dose reduction of 82% with 100% ASIR™.

Conclusions:

The authors’ work was conducted to identify the dose reduction limits of ASiR™ for a pediatric oncology population using automatic tube current modulation. Improvements in noise levels from ASiR™ reconstruction were adapted to provide lower radiation exposure (i.e., lower mA) instead of improved image quality. We have demonstrated for the image quality standards required at our institution, a maximum dose reduction of 82% can be achieved using 100% ASiR™; however, to negate changes in the appearance of reconstructed images using ASiR™ with a medium to low frequency noise preserving reconstruction filter (i.e., standard), 40% ASiR™ was implemented in our clinic for 42%–48% dose reduction at all pediatric ages without a visually perceptible change in image quality or image noise.
Superiorization: An optimization heuristic for medical physics
Authors: Herman Gabor T. , Garduño Edgar , Davidi Ran , Censor Yair
Published: August 2012

Purpose:

To describe and mathematically validate the superiorization methodology, which is a recently developed heuristic approach to optimization, and to discuss its applicability to medical physics problem formulations that specify the desired solution (of physically given or otherwise obtained constraints) by an optimization criterion.

Methods:

The superiorization methodology is presented as a heuristic solver for a large class of constrained optimization problems. The constraints come from the desire to produce a solution that is constraints‐compatible, in the sense of meeting requirements provided by physically or otherwise obtained constraints. The underlying idea is that many iterative algorithms for finding such a solution are perturbation resilient in the sense that, even if certain kinds of changes are made at the end of each iterative step, the algorithm still produces a constraints‐compatible solution. This property is exploited by using permitted changes to steer the algorithm to a solution that is not only constraints‐compatible, but is also desirable according to a specified optimization criterion. The approach is very general, it is applicable to many iterative procedures and optimization criteria used in medical physics.

Results:

The main practical contribution is a procedure for automatically producing from any given iterative algorithm its superiorized version, which will supply solutions that are superior according to a given optimization criterion. It is shown that if the original iterative algorithm satisfies certain mathematical conditions, then the output of its superiorized version is guaranteed to be as constraints‐compatible as the output of the original algorithm, but it is superior to the latter according to the optimization criterion. This intuitive description is made precise in the paper and the stated claims are rigorously proved. Superiorization is illustrated on simulated computerized tomography data of a head cross section and, in spite of its generality, superiorization is shown to be competitive to an optimization algorithm that is specifically designed to minimize total variation.

Conclusions:

The range of applicability of superiorization to constrained optimization problems is very large. Its major utility is in the automatic nature of producing a superiorization algorithm from an algorithm aimed at only constraints‐compatibility; while nonheuristic (exact) approaches need to be redesigned for a new optimization criterion. Thus superiorization provides a quick route to algorithms for the practical solution of constrained optimization problems.
Spatial geometry of the rotating disk and its non-rotating counterpart
Authors: Kassner Klaus
Published: August 2012

A general relativistic description of a disk rotating at constant angular velocity is given. It is argued that describing this situation using general relativity poses fewer conceptual problems than using special relativity. For observers on the disk, the geometry of their proper space is hyperbolic. This has interesting consequences concerning their interpretation of the geometry of a non-rotating disk with the same radius. The influence of clock synchronization on spatial measurements is discussed.
An item response curves analysis of the Force Concept Inventory
Authors: Morris Gary A. , Harshman Nathan , Branum-Martin Lee , Mazur Eric , Mzoughi Taha , Baker Stephen D.
Published: August 2012

Several years ago, we introduced the idea of item response curves (IRC), a simplistic form of item response theory (IRT), to the physics education research community as a way to examine item performance on diagnostic instruments such as the Force Concept Inventory (FCI). We noted that a full-blown analysis using IRT would be a next logical step, which several authors have since taken. In this paper, we show that our simple approach not only yields similar conclusions in the analysis of the performance of items on the FCI to the more sophisticated and complex IRT analyses but also permits additional insights by characterizing both the correct and incorrect answer choices. Our IRC approach can be applied to a variety of multiple-choice assessments but, as applied to a carefully designed instrument such as the FCI, allows us to probe student understanding as a function of ability level through an examination of each answer choice. We imagine that physics teachers could use IRC analysis to identify prominent misconceptions and tailor their instruction to combat those misconceptions, fulfilling the FCI authors’ original intentions for its use. Furthermore, the IRC analysis can assist test designers to improve their assessments by identifying nonfunctioning distractors that can be replaced with distractors attractive to students at various ability levels.
A Breath of Fresh Alveoli
Authors: Calfee Carolyn S.
Published: August 2012

A case report suggests that the adult human lung is capable of partial regrowth after lung resection.
Specificity of Associations between Bacteria and the Coral Pocillopora meandrina during Early Development
Authors: Apprill Amy , Marlow Heather Q. , Martindale Mark Q. , Rappé Michael S.
Published: August 2012

Relationships between corals and specific bacterial associates are thought to play an important role in coral health. In this study, the specificity of bacteria associating with the coralPocillopora meandrinawas investigated by exposing coral embryos to various strains of cultured marine bacteria, sterile seawater, or raw seawater and examining the identity, density, and location of incorporated cells. The isolates utilized in this experiment included members of the Roseobacter and SAR11 clades of theAlphaproteobacteria, aPseudoalteromonasspecies of theGammaproteobacteria, and aSynechococcusspecies of theCyanobacteriaphylum. Based on terminal restriction fragment length polymorphism analysis of small-subunit rRNA genes, similarities in bacterial communities associated with 170-h-old planulae were observed regardless of treatment, suggesting that bacteria may have been externally associated from the outset of the experiment. Microscopic examination ofP. meandrinaplanulae by fluorescencein situhybridization with bacterial and Roseobacter clade-specific oligonucleotide probes revealed differences in the densities and locations of planulae-associated cells. Planulae exposed to either raw seawater or strains ofPseudoalteromonasand Roseobacter harbored the highest densities of internally associated cells, of which 20 to 100% belonged to the Roseobacter clade. Planulae exposed to sterile seawater or strains of the SAR11 clade andSynechococcusdid not show evidence of prominent bacterial associations. Additional analysis of the raw-seawater-exposed planulae via electron microscopy confirmed the presence of internally associated prokaryotic cells, as well as virus-like particles. These results suggest that the availability of specific microorganisms may be an important factor in the establishment of coral-bacterial relationships.
A Novel Tool for Specific Detection and Quantification of Chicken/Turkey Parvoviruses To Trace Poultry Fecal Contamination in the Environment
Authors: Carratalà Anna , Rusinol Marta , Hundesa Ayalkibet , Biarnes Mar , Rodriguez-Manzano Jesus , Vantarakis Apostolos , Kern Anita , Suñen Ester , Girones Rosina , Bofill-Mas Sílvia
Published: August 2012

Poultry farming may introduce pathogens into the environment and food chains. High concentrations of chicken/turkey parvoviruses were detected in chicken stools and slaughterhouse and downstream urban wastewaters by applying new PCR-based specific detection and quantification techniques. Our results confirm that chicken/turkey parvoviruses may be useful viral indicators of poultry fecal contamination.
Predatory Bacteria as Natural Modulators of Vibrio parahaemolyticus and Vibrio vulnificus in Seawater and Oysters
Authors: Richards Gary P. , Fay Johnna P. , Dickens Keyana A. , Parent Michelle A. , Soroka Douglas S. , Boyd E. Fidelma
Published: August 2012

This study shows that naturally occurring
Vibrio
predatory bacteria (VPB) exert a major role in controlling pathogenic vibrios in seawater and shellfish. The growth and persistence of
Vibrio parahaemolyticus
and
Vibrio vulnificus
were assessed in natural seawater and in the Eastern oyster,
Crassostrea virginica
. The pathogens examined were
V. vulnificus
strain VV1003,
V. parahaemolyticus
O1:KUT (KUT stands for K untypeable), and
V. parahaemolyticus
O3:K6 and corresponding O3:K6 mutants deficient in the
toxRS
virulence regulatory gene or the
rpoS
alternative stress response sigma factor gene. Vibrios were selected for streptomycin resistance, which facilitated their enumeration. In natural seawater, oysters bioconcentrated each
Vibrio
strain for 24 h at 22°C; however, counts rapidly declined to near negligible levels by 72 h. In natural seawater with or without oysters, vibrios decreased more than 3 log units to near negligible levels within 72 h. Neither
toxRS
nor
rpoS
had a significant effect on
Vibrio
levels. In autoclaved seawater,
V. parahaemolyticus
O3:K6 counts increased 1,000-fold over 72 h. Failure of the vibrios to persist in natural seawater and oysters led to screening of the water samples for VPB on lawns of
V. parahaemolyticus
O3:K6 host cells. Many VPB, including
Bdellovibrio
and like organisms (BALOs;
Bdellovibrio bacteriovorus
and
Bacteriovorax stolpii
) and
Micavibrio aeruginosavorus
-like predators, were detected by plaque assay and electron microscopic analysis of plaque-purified isolates from Atlantic, Gulf Coast, and Hawaiian seawater. When
V. parahaemolyticus
O3:K6 was added to natural seawater containing trace amounts of VPB,
Vibrio
counts diminished 3 log units to nondetectable levels, while VPB increased 3 log units within 48 h. We propose a new paradigm that VPB are important modulators of pathogenic vibrios in seawater and oysters.
The Helical MreB Cytoskeleton in Escherichia coli MC1000/pLE7 Is an Artifact of the N-Terminal Yellow Fluorescent Protein Tag
Authors: Swulius Matthew T. , Jensen Grant J.
Published: August 2012

Based on fluorescence microscopy, the actin homolog MreB has been thought to form extended helices surrounding the cytoplasm of rod-shaped bacterial cells. The presence of these and other putative helices has come to dominate models of bacterial cell shape regulation, chromosome segregation, polarity, and motility. Here we use electron cryotomography to show that MreB does in fact form extended helices and filaments in
Escherichia coli
when yellow fluorescent protein (YFP) is fused to its N terminus but native (untagged) MreB expressed to the same levels does not. In contrast, mCherry fused to an internal loop (MreB-RFP
SW
) does not induce helices. The helices are therefore an artifact of the placement of the fluorescent protein tag. YFP-MreB helices were also clearly distinguishable from the punctate, “patchy” localization patterns of MreB-RFP
SW
, even by standard light microscopy. The many interpretations in the literature of such punctate patterns as helices should therefore be reconsidered.
Interaction of CarD with RNA Polymerase Mediates Mycobacterium tuberculosis Viability, Rifampin Resistance, and Pathogenesis
Authors: Weiss Leslie A. , Harrison Phillip G. , Nickels Bryce E. , Glickman Michael S. , Campbell Elizabeth A. , Darst Seth A. , Stallings Christina L.
Published: August 2012

Mycobacterium tuberculosis
infection continues to cause substantial human suffering. New chemotherapeutic strategies, which require insight into the pathways essential for
M. tuberculosis
pathogenesis, are imperative. We previously reported that depletion of the CarD protein in mycobacteria compromises viability, resistance to oxidative stress and fluoroquinolones, and pathogenesis. CarD associates with the RNA polymerase (RNAP), but it has been unknown which of the diverse functions of CarD are mediated through the RNAP; this question must be answered to understand the CarD mechanism of action. Herein, we describe the interaction between the
M. tuberculosis
CarD and the RNAP β subunit and identify point mutations that weaken this interaction. The characterization of mycobacterial strains with attenuated CarD/RNAP β interactions demonstrates that the CarD/RNAP β association is required for viability and resistance to oxidative stress but not for fluoroquinolone resistance. Weakening the CarD/RNAP β interaction also increases the sensitivity of mycobacteria to rifampin and streptomycin. Surprisingly, depletion of the CarD protein did not affect sensitivity to rifampin. These findings define the CarD/RNAP interaction as a new target for chemotherapeutic intervention that could also improve the efficacy of rifampin treatment of tuberculosis. In addition, our data demonstrate that weakening the CarD/RNAP β interaction does not completely phenocopy the depletion of CarD and support the existence of functions for CarD independent of direct RNAP binding.
Undecaprenyl Pyrophosphate Involvement in Susceptibility of Bacillus subtilis to Rare Earth Elements
Authors: Inaoka Takashi , Ochi Kozo
Published: August 2012

The rare earth element scandium has weak antibacterial potency. We identified a mutation responsible for a scandium-resistant phenotype in
Bacillus subtilis
. This mutation was found within the
uppS
gene, which encodes undecaprenyl pyrophosphate synthase, and designated
uppS86
(for the Thr-to-Ile amino acid substitution at residue 86 of undecaprenyl pyrophosphate synthase). The
uppS86
mutation also gave rise to increased resistance to bacitracin, which prevents cell wall synthesis by inhibiting the dephosphorylation of undecaprenyl pyrophosphate, in addition to enhanced amylase production. Conversely, overexpression of the wild-type
uppS
gene resulted in increased susceptibilities to both scandium and bacitracin. Moreover, the mutant lacking undecaprenyl pyrophosphate phosphatase (BcrC) showed increased susceptibility to all rare earth elements tested. These results suggest that the accumulation of undecaprenyl pyrophosphate renders cells more susceptible to rare earth elements. The availability of undecaprenyl pyrophosphate may be an important determinant for susceptibility to rare earth elements, such as scandium.
Supervised Exercise plus Acupuncture for Moderate to Severe Knee Osteoarthritis: A Small Randomised Controlled Trial
Authors: Soni Anushka , Joshi Abhay , Mudge Nicola , Wyatt Matthew , Williamson Lyn
Published: August 2012

Objectives

Although total knee replacement (TKR) is cost effective and successful in most cases, patient-reported outcome measures demonstrate 20% of people remain unsatisfied at 1 year after a technically successful procedure. Our group has previously shown that patients with severe knee osteoarthritis (OA) awaiting surgery can achieve a short-term reduction in symptom severity when treated with acupuncture, and that a trend towards improved walking distance, as a measure of function, is achieved with preoperative supervised exercise. The aim of this study was to evaluate the effect of combined acupuncture and physiotherapy on preoperative and postoperative pain and function.

Methods

A total of 56 patients awaiting TKR surgery were randomised to receive either combined physiotherapy and acupuncture or a standardised exercise and advice leaflet. Pain and function were measured primarily using the Oxford Knee Score (OKS), with assessments at baseline prior to intervention, 6 and 12 weeks after intervention and at 3 months postoperatively.

Results

Due to the introduction of the 18-week waiting times target during this study, the required sample size was not achieved. There were no significant differences demonstrated between the control and treatment groups for OKS. Seven patients withdrew from surgery because of symptomatic improvement in their knees: six from the treatment group and one from the control group (OR 7.64, 95% CI 0.86 to 68.20).

Conclusions

This study demonstrated that the use of combined acupuncture and physiotherapy in the treatment of patients with moderate to severe knee OA preoperatively did not improve patient outcome postoperatively. As the study was underpowered, a larger trial is required to examine this result further.
Hibernoma with metabolic impact?
Authors: Vijgen Guy H E J , Bouvy Nicole D , Smidt Marjolein , Kooreman Loes , Schaart Gert , van Marken Lichtenbelt Wouter
Published: August 2012

A hibernoma is a benign tumour of brown adipose tissue (BAT). BAT is also present in physiological depots, previously considered residual. However, in 2009 functional BAT in adults was reported. Metabolically active BAT is suggested to significantly influence the energy balance and increasing BAT activity could possibly treat obesity. This strongly increased the interest in BAT in man and currently more research is conducted. We describe the case of an intramuscular hibernoma and illustrate the pathophysiology of the observed hibernoma in relation to recent insights on physiological BAT. Immunofluorescence staining of the hibernoma showed the presence of uncoupling-protein-1, a protein specific for active BAT. This suggests that this hibernoma contains BAT that could possibly contribute to the human energy balance.
Missed perforation presenting as sympathetic ophthalmia in an adolescent Malay girl
Authors: Bastion Mae-Lynn Catherine , Mohamad Muhaya Hj
Published: August 2012

To describe the rare presentation of sympathetic ophthalmia in a teenage girl with no previous known ocular injury.
Cerebral vasospasm following tumor resection
Authors: Alotaibi Naif M , Lanzino Giuseppe
Published: August 2012

Objective

To perform a systematic review of the literature of cases of vasospasm following tumor resection and to discuss possible etiologies, diagnosis and management of this complication.

Methods

A literature search was performed using relevant search key words to identify cases of ‘cerebral vasospasm’ as a complication following tumor resection. Articles were identified by searching MEDLINE and PubMed databases. Relevant cross references were added by manually searching the references of all retrieved articles.

Results

There were a total of 56 patients in our initial search but only 40 cases matched our inclusion criteria. Pituitary tumors and sellar area were the most common pathologies and location associated with this complication. Average time interval to development of symptomatic vasospasm was 8 days and mortality was high (30%). The most common encountered causative factors were vascular factors (vessel encasement, displacement and narrowing) and presence of blood in the basal cisterns in postoperative scans.

Conclusions

‘Cerebral vasospasm’ after tumor resection is a rare but challenging complication with very high morbidity and mortality in reported cases. Vasospasm following brain tumor surgery shares some of the same clinical variables (time interval, causative factors, morbidity and death rates) of vasospasm after aneurysmal subarachnoid hemorrhage. A high index of suspicion is required for early diagnosis and prompt management which are key elements of final outcome.
Republished: Pathogenesis and diagnosis of myocarditis
Authors: Elamm Chantal , Fairweather DeLisa , Cooper Leslie T
Published: August 2012

Acute myocarditis is an inflammatory disease of the heart muscle that may progress to dilated cardiomyopathy and chronic heart failure. A number of factors including the sex hormone testosterone, components of innate immunity, and profibrotic cytokines have been identified in animal models as important pathogenic mechanisms that increase inflammation and susceptibility to chronic dilated cardiomyopathy. The clinical presentation of acute myocarditis is non-specific and mimics more common causes of heart failure and arrhythmias. Suspected myocarditis is currently confirmed using advanced non-invasive imaging and histopathologic examination of heart tissue. However, the diverse presentations of myocarditis and the lack of widely available, safe, and accurate non-invasive diagnostic tests remain major obstacles to early diagnosis and population based research. Recent advances in the understanding of disease pathogenesis described in this review should lead to more accurate diagnostic algorithms and non-invasive tests.
Desiccation cracking behavior of polypropylene fiber–reinforced clayey soil
Authors: Tang Chao-Sheng , Shi Bin , Cui Yu-Jun , Liu Chun , Gu Kai
Published: August 2012

Improvement of the crack resistance of clayey soils by fiber reinforcement was investigated using initially saturated and fiber-reinforced soil specimens subjected to desiccation. An image-processing technique was used to quantitatively describe the effect of fiber addition on the geometrical and morphological characteristics of crack patterns. The results show that the soil desiccation cracking behavior was significantly influenced by fiber inclusion: the crack resistance was significantly improved and the amount of desiccation cracks was significantly reduced by fiber addition. Generally, the surface crack ratio (surface of cracks to total surface), number of clods, average length and width of cracks, and crack network connectivity decreased with increasing fiber content, while the average area of clods, number of nodes per unit area, number of crack segments per unit area, crack density, and specimen integrity increased. During crack propagation, the surface crack ratio increased with decreasing water content and finally reached stabilization. Comparison between the surface crack ratio of the natural soil specimen and that of the fiber-reinforced soil specimen showed that the former was always higher than the latter. The fiber length was found to have an insignificant effect on the soil desiccation cracking behavior.
Cyclic axial behaviour of piles and pile groups in sand
Authors: Li Zheming , Bolton Malcolm D. , Haigh Stuart K.
Published: August 2012

Piled foundations are often subjected to cyclic axial loads. This is particularly true for the piles of offshore structures, which are subjected to rocking motions caused by wind or wave actions, and for those of transport structures, which are subjected to traffic loads. As a result of these cyclic loads, excessive differential or absolute settlements may be induced during the piles’ service life. In the research presented here, centrifuge modelling of single piles and pile groups was conducted to investigate the influence of cyclic axial loads on the performance of piled foundations. The influence of installation method was investigated and it was found that the cyclic response of a pile whose jacked installation was modelled correctly is much stiffer than that of a bored pile. During displacement-controlled axial load cycling, the pile head stiffness reduces with an increasing number of cycles, but at a decreasing rate; during force-controlled axial load cycling, more permanent settlement is accumulated for a bored pile than for a jacked pile. The performance of individual piles in a pile group subjected to cyclic axial loads is similar to that of a single pile, without any evident group effect. Finally, a numerical analysis of axially loaded piles was validated by centrifuge test results. Cyclic stiffness of soil at the base of pre-jacked piles increases dramatically, while at base of jacked piles it remains almost constant.
SPINOR GEOMETRY
Authors: NICOLAIDIS A. , KIOSSES V.
Published: August 2012

It has been proposed that quantum mechanics and string theory share a common inner syntax, the relational logic of C. S. Peirce. Along this line of thought we consider the relations represented by spinors. Spinor composition leads to the emergence of Minkowski space–time. Inversely, the Minkowski space–time is istantiated by the Weyl spinors, while the merger of two Weyl spinors gives rise to a Dirac spinor. Our analysis is applied also to the string geometry. The string constraints are represented by real spinors, which create a parametrization of the string worldsheet identical to the Enneper–Weierstass representation of minimal surfaces. Further, a spinorial study of the AdS3 space–time reveals a Hopf fibration AdS3 → AdS2. The conformal symmetry inherent in AdS3 is pointed out. Our work indicates the hidden ties between logic-quantum mechanics-string theory-geometry and vindicates the Wheeler's proposal of pregeometry as a large network of logical propositions.
LOCAL INSTABILITY PROBLEM OF IMAGE SEGMENTATION ALGORITHMS: SYSTEMATIC STUDY AND AN ENSEMBLE-BASED SOLUTION
Authors: FRANEK LUCAS , JIANG XIAOYI , WATTUYA PAKAKET
Published: August 2012

The region-based segmentation paradigm is a well known technique for image segmentation. In the first part of this work the robustness of region-based algorithms is studied. It is shown that within a small parameter range, which leads to good segmentation results in the majority of cases, bad segmentation results may occur. In fact, such local instability is a problem of region-based methods and reasons for its occurrence are discussed. In the second part of the work, an ensemble solution for this problem based on the median concept is proposed. Two variants, set median and generalized median, are presented and experimentally compared. Extensive experimental results demonstrate the potential of the proposed median approach for solving the instability problem.
THE IMPACT OF RESOURCE AND TEMPERATURE ON MALARIA TRANSMISSION
Authors: WAN HUI , ZHU HUAIPING
Published: August 2012

In this paper, we extend the famous Ross's model to establish a new model for malaria to incorporate the impact of blood meal resources for mosquitoes and temperature on the transmission of malaria. A dynamical analysis for the new model is provided and it is shown that with the new growth rate for mosquitoes, the transmission dynamics of malaria becomes more complex and the Hopf bifurcation may occur which induces sustained oscillations not only in the mosquito population but also in the infected human population. Our results suggest that the abundance of blood meal resource for mosquitoes can be a factor which is important to characterize the transmission dynamics of malaria in a region. The impact of maturation time delay related to temperature changes is also analyzed which suggests that increasing the temperature exacerbates the transmission of malaria.
Intrinsic firing properties in the avian auditory brain stem allow both integration and encoding of temporally modulated noisy inputs in vitro
Authors: Kreeger Lauren J. , Arshed Arslaan , MacLeod Katrina M.
Published: August 2012

The intrinsic properties of tonically firing neurons in the cochlear nucleus contribute to representing average sound intensity by favoring synaptic integration across auditory nerve inputs, reducing phase locking to fine temporal acoustic structure and enhancing envelope locking. To determine whether tonically firing neurons of the avian cochlear nucleus angularis (NA) resemble ideal integrators, we investigated their firing responses to noisy current injections during whole cell patch-clamp recordings in brain slices. One subclass of neurons (36% of tonically firing neurons, mainly subtype tonic III) showed no significant changes in firing rate with noise fluctuations, acting like pure integrators. In contrast, many tonically firing neurons (>60%, mainly subtype tonic I or II) showed a robust sensitivity to noisy current fluctuations, increasing their firing rates with increased fluctuation amplitudes. For noise-sensitive tonic neurons, the firing rate vs. average current curves with noise had larger maximal firing rates, lower gains, and wider dynamic ranges compared with FI curves for current steps without noise. All NA neurons showed fluctuation-driven patterning of spikes with a high degree of temporal reliability and millisecond spike time precision. Single-spiking neurons in NA also responded to noisy currents with higher firing rates and reliable spike trains, although less precisely than nucleus magnocellularis neurons. Thus some NA neurons function as integrators by encoding average input levels over wide dynamic ranges regardless of current fluctuations, others detect the degree of coherence in the inputs, and most encode the temporal patterns contained in their inputs with a high degree of precision.
A Case of Horner's Syndrome following Ultrasound-Guided Infraclavicular Brachial Plexus Block
Authors: Walid Trabelsi , Mondher Belhaj Amor , Mohamed Anis Lebbi , Mustapha Ferjani
Published: August 2012

Horner’s syndrome results from paralysis of the ipsilateral sympathetic cervical chain (stellate ganglion) caused by surgery, drugs (mainly high concentrations of local anesthetics), local compression (hematoma or tumor), or inadequate perioperative positioning of the patient. It occurs in 100% of the patients with an interscalene block of the brachial plexus and can also occur in patients with other types of supraclavicular blocks.In this case report, we presented a case of Horner’s syndrome after performing an ultrasound-guided infraclavicular brachial plexus block with 15 mL of bupivacaine 0.5%. It appeared 40 minutes after the block with specific triad (ptosis, miosis, and exophtalmia) and quickly disappears within 2 hours and a half without any sequelae. Horner's syndrome may be described as an unpleasant side effect because it has no clinical consequences in itself. For this reason anesthesiologists should be aware of this syndrome, and if it occurs patients should be reassured and monitored closely.