bluuebunny/crossref_metadata_2025 huggingface dataset:
An Approximate Dynamic Programming Approach to Benchmark Practice-Based Heuristics for Natural Gas Storage Valuation
Authors: Lai Guoming , Margot François , Secomandi Nicola
Published: February 2010

The valuation of the real option to store natural gas is a practically important problem that entails dynamic optimization of inventory trading decisions with capacity constraints in the face of uncertain natural gas price dynamics. Stochastic dynamic programming is a natural approach to this valuation problem, but it does not seem to be widely used in practice because it is at odds with the high-dimensional natural gas price evolution models that are widespread among traders. According to the practice-based literature, practitioners typically value natural gas storage heuristically. The effectiveness of the heuristics discussed in this literature is currently unknown because good upper bounds on the value of storage are not available. We develop a novel and tractable approximate dynamic programming method that, coupled with Monte Carlo simulation, computes lower and upper bounds on the value of storage, which we use to benchmark these heuristics on a set of realistic instances. We find that these heuristics are extremely fast to execute but significantly suboptimal compared to our upper bound, which appears to be fairly tight and much tighter than a simpler perfect information upper bound; computing our lower bound takes more time than using these heuristics, but our lower bound substantially outperforms them in terms of valuation. Moreover, with periodic reoptimizations embedded in Monte Carlo simulation, the practice-based heuristics become nearly optimal, with one exception, at the expense of higher computational effort. Our lower bound with reoptimization is also nearly optimal, but exhibits a higher computational requirement than these heuristics. Besides natural gas storage, our results are potentially relevant for the valuation of the real option to store other commodities, such as metals, oil, and petroleum products.
A Stochastic Programming Based Inventory Policy for Assemble-to-Order Systems with Application to the W Model
Authors: Doğru Mustafa K. , Reiman Martin I. , Wang Qiong
Published: February 2010

We consider assemble-to-order inventory systems with identical component lead times. We use a stochastic program (SP) to develop an inventory strategy that allows preferential component allocation for minimizing total inventory cost. We prove that the solution of a relaxation of this SP provides a lower bound on total inventory cost for all feasible policies. We demonstrate and test our approach on the W system, which involves three components used to produce two products. (There are two unique parts and a common part. Each product uses the common part and its own unique part.) For the W system, we develop efficient solution procedures for the SP as well as the relaxed SP. We define a simple priority allocation policy that mimics the second-stage SP recourse solution and set base-stock levels according to the first-stage SP solution. We show that our policy achieves the lower bound and is, thus, optimal in two situations: when a certain symmetry condition in the cost parameters holds and when the SP solution satisfies a “balanced capacity” condition. For other cases, numerical results demonstrate that our policy works well and outperforms alternative approaches in many circumstances.
Technical Note—Capacitated Serial Inventory Systems: Sample Path and Stability Properties Under Base-Stock Policies
Authors: Huh Woonghee Tim , Janakiraman Ganesh , Nagarajan Mahesh
Published: February 2010

We study a periodically reviewed multiechelon serial inventory system with a capacity constraint on the order quantity at every stage. Under echelon base-stock policies, we demonstrate a simple sample-path result that maps the echelon shortfalls in the serial system to the shortfalls of suitably defined single-stage systems. Because the shortfall processes of single-stage systems are well understood, our result allows us to reinterpret results in the literature on the stability and regeneration times of such multiechelon systems in a simpler fashion with weaker assumptions.
Untersuchungen an magnetostriktiven MikroaktorenAnalysis of Magnetostrictive Microactuators
Authors: Albach Thorsten , Sutor Alexander , Lerch Reinhard
Published: February 2010

Der magnetostriktive Wandlungseffekt eröffnet neue Wege, Aktoren für Mikrosysteme (MEMS) herzustellen. Speziell die auf dem Prinzip des monomorphen Biegebalkens basierenden magnetostriktiven Mikroaktoren bieten interessante Anwendungsfelder. Diese Aktoren werden unter Einfluss äußerer Magnetfelder zu Biegung und Schwingung angeregt. Es werden Berechnungsmethoden, Herstellungsprozess und Messtechnik vorgestellt, um die Entwicklung von Mikrosystemen basierend auf derartigen Mikroaktoren zu ermöglichen. Der Fokus der Untersuchungen liegt auf den mechanischen Eigenfrequenzen sowie den magnetostriktiven Kennlinien der Aktoren. Aufgrund der Ergebnisse lassen sich die gewählten Berechnungsmethoden sowie die Reproduzierbarkeit des Herstellungsprozesses verifizieren und lineare Arbeitsbereiche definieren.
Messtechnische Eigenschaften von Dehnungssensoren aus Kohlenstoff-Filamentgarn in einem VerbundwerkstoffMeasuring Performance of Carbon Filament Yarn Strain Sensors Embedded in a Composite
Authors: Kunadt Andreas , Starke Eric , Pfeifer Günther , Cherif Chokri
Published: February 2010

Mit in Verbundwerkstoffen eingebettetem Kohlenstoff-Filamentgarn können mittlere Dehnungen großer Messflächen erfasst werden. Zur Abschätzung der messtechnischen Praxistauglichkeit wurden in einen Glasfaser-Polypropylen-Verbundwerkstoff integrierte Kohlenstoff-Filamentgarn-Dehnungssensoren hinsichtlich der erreichbaren Messgenauigkeit bei Kurzzeitmessungen (maximal 15 Minuten Messzeit) untersucht. Anhand vergleichender Dehnungsmessungen mit Metallfolien-Dehnungsmessstreifen wurden der Übertragungsfaktor, der Linearitäts-, Hysterese- und Kriechfehler sowie die Wiederholbarkeit bestimmt. Die Einflüsse des Verbundwerkstoffes und der Temperatur wurden ebenso untersucht wie verschiedene Technologien zur elektrischen Kontaktierung von Kohlenstoff-Filamentgarn.
Optofluidische Komponenten in der FlüssigkeitssensorikOptofluidic Elements in Liquid-based Sensor Systems
Authors: Rosenauer Michael , Weber Emanuel , Stampfl Jürgen , Vellekoop Michael J.
Published: February 2010

In der biotechnologischen Flüssigkeitssensorik spielen adaptive optische Systeme zur Anregung und Detektion von Lumineszenzsignalen eine wichtige Rolle. Diese Arbeit untersucht zwei Typen von optofluidischen Elementen, welche sowohl den Funktionsumfang als auch die Sensitivität sogenannter “Lab-on-a-chips” erhöhen können. Im ersten Teil wird eine hydrodynamisch verformbare Flüssigkeitslinse mit dreidimensionaler Fokusveränderbarkeit auf Basis einer mikrofluidischen Kanalstruktur diskutiert. Das zweite Sensorsystem beinhaltet einen adaptierbaren Flüssigkeitslichtleiter. Die Prototypen wurden in einem transparenten Photopolymer mit Mikro-Stereolithographie gefertigt.
First report of ectopic ACTH syndrome and PTHrP-induced hypercalcemia due to a hepatoblastoma in a child
Authors: Grunewald Thomas G P , von Luettichau Irene , Welsch Ulrich , Dörr Helmuth-Günther , Höpner Frank , Kovacs Kalman , Burdach Stefan , Rabl Wolfgang
Published: February 2010

Context

Only occasionally, endocrine-active tumors develop directly from hepatic tissue, and may lead to paraneoplastic syndromes (PNS). PNS mostly accompany malignancy of adulthood and are exceedingly rare in children.

Patient

A girl aged 6 years and 9 months presented with a 2-month history of rapidly progressive weight gain, abdominal distension, and polyuria/pollakiuria accompanied by short episodes of abdominal pain. She showed the typical clinical features of Cushing's syndrome and a huge hepatic mass. An abdominal computed tomography (CT) scan revealed a large liver tumor. Blood glucose and serum calcium were greatly elevated.

Design and objective

Case report describing the causative relationship of the clinical findings.

Methods

Physical examination; ultrasound of the abdomen; CT scan of the abdomen and the chest; conventional X-rays; routine hematology; blood chemistry and multiple parameters of calcium and phosphorus metabolism; multisteroid analysis in serum and urine; adrenocortical stimulation and suppression tests; histopathological assessment of the resected tumor; immunohistochemistry for ACTH, β-endorphin, corticotrophin-releasing hormone (CRH), and PTH-related peptide (PTHrP); electron microscopy of tumor cells; ACTH and CRH extraction from the tumor tissue; and clinical follow-up for more than 20 years.

Results

Giant hepatoblastoma (HB; ∼1000 ml volume) of the right lobe of the liver with combined ectopic ACTH syndrome and PTHrP-induced tumor-associated hypercalcemia. Wide local excision and polychemotherapy led to complete reversal of the paraneoplastic phenotype.

Conclusions

This is the first report of an endocrine-active HB causing both Cushing's syndrome and PTHrP-related ‘humoral hypercalcemia of malignancy’. This information should be added to the well-known β-human chorionic gonadotropin-related paraneoplastic effects of HB in children.
Screening and treatment of retinopathy of prematurity in Markusovszky Teaching Hospital, 1989–2009 (20 years of experiences)
Authors: Kósa Éva , Grasselly Magdolna
Published: February 2010

A szerzők a koraszülötteknél a retinopathia (ROP) gyakoriságát vizsgálták egy megyei kórházban.Módszer:1989. január 1. és 2009. január 1. között 543 koraszülött szemfenékvizsgálatának eredményét elemezték.Eredmények:34 koraszülött mindkét szemén (6,3%) megtalálták a betegség tüneteit. A ROP a legnagyobb arányban, 29,5%-ban (23/78 eset) 1000 g születési súly alatt fordult elő. Spontán gyógyulás összesen 10 gyermek 19 szemén következett be. A ROP 25 újszülött 49 szemén elérte a „küszöbbetegséget”, azaz kezelést igényelt. Cryopexia 16 gyermek mindkét szemén történt, lézer-fotokoagulációt 9 koraszülött 17 szemén végeztek. A cryopexia után 26 szem gyógyult, 6 szemen a ROP tünetei progrediáltak. Lézer-fotokoagulációt követően gyógyulás 16 szemen következett be, egy szemen volt a kezelés eredménytelen. A húsz év alatt mindössze két gyermek mindkét, és három gyermek egy-egy szemén alakult ki V. stádiumú ROP.Következtetés:az előírásszerűen végzett szemészeti szűrővizsgálat és az ezek alapján kiszűrt „küszöb-ROP” eseteiben az időben elvégzett cryopexia vagy lézer-fotokoaguláció eredményes kezelésnek bizonyult a súlyos látáskárosodás megelőzésére.
Analysis of clinical course of severe acute biliary and non biliary pancreatitis: a comparative study
Authors: Kotán Róbert , Pósán János , Sápy Péter , Damjanovich László , Szentkereszty Zsolt
Published: February 2010

Az akut pancreatitis viszonylag gyakran előforduló betegség. Évenként 5 és 80 közötti új megbetegedés esik 100 000 lakosra, és ez a szám az utóbbi években növekedést mutat a különböző tanulmányok szerint. A két fő etiológiai faktor az alkohol és az epekövesség. Az alkoholos eredetű hasnyálmirigy-gyulladás a férfiak körében, a biliaris pancreatitis a nők körében gyakoribb.
Célkitűzés:
a szerzők súlyos akut pancreatitis miatt kezelt betegek adatait elemezik, arra keresve a választ, hogy milyen eltérő sajátságokkal rendelkezik a biliaris és a más etiológiájú pancreatitis.
Betegek és módszer:
a szerzők 139, súlyos akut pancreatitisben szenvedő beteget kezeltek, akiket etiológiai szempontból két csoportra osztottak: az epeköves (A csoport) és a nem epeköves (B csoport) talajon kialakult súlyos hasnyálmirigy-gyulladásban szenvedők csoportjára. Összehasonlították a két csoport nem és kor szerinti sajátosságait, a mortalitási és a morbiditási adatokat, a műtétek és az ápolási napok számát. A statisztikai analízishez a χ
2
-tesztet alkalmazták.
Eredmények:
a szövődmények az epés (A) csoportban súlyosabbak voltak, mint a nem epés (B) csoportban. A halálozás az A csoportban 17,8%-nak, a B csoportban 13,8%-nak bizonyult, míg az átlagos 15,1% volt. A mortalitás a nők körében az A csoportban szignifikánsan magasabb volt.
Következtetések:
a súlyos epés akut pancreatitisben szenvedő nőbetegek esetében súlyosabb lefolyással, magasabb halálozási aránnyal kell számolnunk. A szerzők az idős, egyéb betegségekkel terhelt epeköves nőknél még a szövődmények jelentkezése előtt elektív cholecystectomiát javasolnak.
Targeting mediators of Wnt signalling pathways by GnRH in gonadotropes
Authors: Gardner Samantha , Stavrou Emmanouil , Rischitor Patricia E , Faccenda Elena , Pawson Adam J
Published: February 2010

The binding of GnRH to its receptor on pituitary gonadotropes leads to the targeting of a diverse array of signalling mediators. These mediators drive multiple signal transduction pathways, which in turn regulate a variety of cellular processes, including the biosynthesis and secretion of the gonadotropins LH and FSH. Advances in our understanding of the mechanisms and signalling pathways that are recruited to regulate gonadotrope function are continually being made. This review will focus on the recent demonstration that key mediators of the canonical Wnt signalling pathway are targeted by GnRH in gonadotropes, and that these may play essential roles in regulating the expression of many of the key players in gonadotrope biology, including the GnRH receptor and the gonadotropins.
Tumor Resistance Explained by Hormesis
Authors: Calabrese Edward J. , Nascarella Marc A.
Published: February 2010

Enhanced drug (GDC 0449) resistance in a mouse model for human medulloblastoma is shown in the present paper to act via an hormetic response. This has significant implications, imposing constraints on the quantitative features of the dose response of the chemotherapeutic agent, affecting optimal study design, mechanism assessment strategy, potential for tumor rebound, patient relapse and disease outcome.
Stereoselective cyclo-addition reactions of azomethine ylides catalysed by in situ generated Ag(I)/bisphosphine complexes
Authors: Grigg Ronald , Husinec Suren , Savic Vladimir
Published: February 2010

Stereoselective cyclo-addition reactions of azomethine ylides promoted by in situ generated Ag(I)/bisphosphine complexes were studied. Under the optimized conditions, the pyrrolidine products were isolated in up to 84 % yield and with up to 71% e.e. The effects of various reaction variables on the stereoselectivity were also investigated.
Substituted pyridopyrimidinones, Part IV: 2-chloro-4h-pyrido[1,2-a]pyrimidin-4-one as a synthone of some new heterotricycles
Authors: Abass Mohamed , Ismail Mostafa , Abdel-Monem Wafaa , Mayas Aisha
Published: February 2010

2-Chloro-4H-pyrido[1,2-a]pyrimidin-4-one (1) was utilized as a synthone precursor to prepare novel heterotricyclic systems. 2-Azido and 2-hydrazino derivatives (2 and 3) were obtained by nucleophilic replacement evolving compound 1. The hydrazine derivative 3 was transformed into the azido derivative 2 by nitrosation. Treatment of compound 3 with [bis(methylthio)methylene] malononitrile afforded 2-pyrazolylpyridopyrimidine 4. When compound 1 was reacted with 5-amino-3-(methylthio)-1H-pyrazole-4-carbonitrile, the same compound 4 was obtained with no evidence for the production of (pyrazolylamino) pyridopyrimidine 5 or pyrazolodipyridopyrimidine 6. Poly-functionalized dipyridopyrimidine 8 was obtained by reaction of compound 1 with 2-[(methylthio)-( phenylamino)methylene]propanedinitrile. Cyanoguanidine was reacted with compound 1 to afford N-pyridopyrimidinylguanidine 9, which was subjected to cyclization reaction, in presence of piperidinium acetate, to give pyridopyrimidopyrimidine 10.
Stability evaluation of house dust mite vaccines for sublingual immunotherapy
Authors: Burazer Lidija , Milovanovic Katarina , Cirkovic-Velickovic Tanja , Gavrovic-Jankulovic Marija
Published: February 2010

Allergen-specific immunotherapy with house dust mite (HDM) allergen extracts can effectively alleviate the symptoms of allergic rhinitis and asthma. The efficacy of the immunotherapeutic treatment is highly dependent on the quality of house dust mite vaccines. This study was performed to assess the stability of house dust mite allergen vaccines prepared for sublingual immunotherapy. Lyophilized Dermatophagoides pteronyssinus (Dpt) mite bodies were the starting material for the production of sublingual vaccines in four therapeutic concentrations. The stability of the extract for vaccine production, which was stored below 4 ?C for one month, showed consistence in the protein profile in SDS PAGE. ELISA-inhibition showed that the potencies of Dpt vaccines during a 12 month period were to 65-80 % preserved at all analyzed therapeutic concentrations. This study showed that glycerinated Dpt vaccines stored at 4?C preserved their IgE-binding potential during a 12 month period, implying their suitability for sublingual immunotherapeutic treatment of HDM allergy.
Essential oils of Thymus pulegioides and Thymus glabrescens from Romania: Chemical composition and antimicrobial activity
Authors: Pavel Mariana , Ristic Mihailo , Stevic Tatjana
Published: February 2010

The aim of this work was to analyse the chemical composition and antimicrobial properties of essential oils isolated from two wild-growing species of thyme (Thymus pulegioides L. and T. glabrescens Willd.) originating from different locations in Romania. The yield of essential oil was determined according to European Pharmacopoeia standards. Qualitative and quantitative analysis of the oils was performed using GC and GC/MS. The antimicrobial activity was tested by the microdilution technique against Gram-negative and Gram-positive bacteria (Escherichia coli, Salmonella typhimurium, S. enteritisdis, Enterobacter cloacae, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, S. epidermidis, Streptococcus faecalis, Bacillus subtilis, Micrococcus luteus, M. flavus and Listeria monocytogenes) and human pathogen yeast Candida albicans. The essential oil of Thymus pulegioides was obtained in a yield of 0.7-1 % (v/d.w. herbal drug) and the main components were carvacrol (50.5-62.6 %), ?-terpinene (9.8-9.9 %) and p-cymene (5.8-7.1 %). The essential oil of T. glabrescens was obtained in a yield of 0.7 (v/d.w. herbal drug) and the main components were geraniol (55.5 %), neryl acetate (11.1 %) and ?-bisabolene (6.7 %). The essential oils inhibited microbial growth at concentrations of 10.8-27 ?l/ml.
Composition and antimicrobial activity of the essential oil of the leaves of black currant (Ribes nigrum L.) cultivar Cacanska crna
Authors: Stevic Tatjana , Savikin Katarina , Ristic Mihailo , Zdunic Gordana , Jankovic Teodora , Krivokuca-Djokic Dragana , Vulic Todor
Published: February 2010

The essential oil from the leaves of the Serbian black currant cultivar Cacanska crna, obtained by hydrodistillation, was analyzed by gas Chromatography flame ionization detection and GC-mass spectrometry. The most abundant volatile compounds were ?3-carene (18.7 %), ?-caryophyllene (17.7 %), sabinene (11.6 %), cis-?-ocimene (10.6 %) and ?-terpinolene (10.6%). The antimicrobial activity of the oil was evaluated against 14 micro-organisms, including two clinical isolated strains, using the broth microdilution method. The most susceptible micro-organisms were Escherichia coli, Streptococcus faecalis, Staphylococcus aureus, Candida albicans and Trichophyton mentagrophytes isolates. Furthermore, the flavonol aglycones in the leaves after acid hydrolysis were qualitatively and quantitatively analysed by HPLC, and quercetin was found to be the dominant compound (84 mg/g dw).
Synthesis, characterization and DNA cleavage activity of nickel(II) adducts with aromatic heterocyclic bases
Authors: Babu Surendra , Krishna Pitchika , Reddy Hussain , Philip G.H.
Published: February 2010

Mixed ligand complexes of nickel(II) with 2,4-dihydroxyacetophenone oxime (DAPO) and 2,4-dihydroxybenzophenone oxime (DBPO) as primary ligands, and pyridine (Py) and imidazole (Im) as secondary ligands were synthesized and characterized by molar conductivity, magnetic moments measurements, as well as by electronic, IR, and 1H-NMR spectroscopy. Electrochemical studies were performed by cyclic voltammetry. The active signals are assignable to the NiIII/II and NiII/I redox couples. The binding interactions between the metal complexes and calf thymus DNA were investigated by absorption and thermal denaturation. The cleavage activity of the complexes was determined using double-stranded pBR322 circular plasmid DNA by gel electrophoresis. All complexes showed increased nuclease activity in the presence of the oxidant H2O2. The nuclease activities of mixed ligand complexes were compared with those of the parent copper(II) complexes.
A study of the formation constants of ternary and quaternary complexes of some bivalent transition metals
Authors: Sharma Sangita , Dalwadi Dipika , Neog Madhurjya
Published: February 2010

The formation of hetero-ligand 1:1:1, M(II)-Opda-Sal/Gly ternary and 1:1:1:1, M(II)-Opda-Sal-Gly quaternary complexes, where M(II) = Ni, Cu, Zn and Cd; Opda = o-phenylenediamine, Sal = salicylic acid, Gly = glycine, was studied pH-metrically in aqueous medium. The formation constants for the resulting ternary and quaternary complexes were evaluated at a constant ionic strength, ? = 0.20 mol dm-3 and temperature, 30?0.1 ?C. The order of the formation constants in terms of the metal ion for both type of complexes was found to be Cu(II) > Ni(II) > Zn(II) > Cd(II). This order was explained based on the increasing number of fused rings, the coordination number of the metal ions, the Irving - William order and the stability of various species. The expected species formed in solution were pruned with the Fortran IV program SPEPLOT and the stability of the ternary and quaternary complexes is explained.
Investigation of the kinetics and mechanism of the glycerol chlorination reaction using gas chromatography-mass spectrometry
Authors: Ling Xiuquan , Lu Dingqiang , Wang Jun , Liang Mingxin , Zhang Shumin , Ren Wei , Chen Jianhui , Ouyang Pingkai
Published: February 2010

As a primary by-product in biodiesel production, glycerol can be used to prepare an important fine chemical, epichlorohydrin, by the glycerol chlorination reaction. Although this process has been applied in industrial production, unfortunately, less attention has been paid to the analysis and separation of the compounds in the glycerol chlorination products. In this study, a convenient and accurate method to determine the products in glycerol chlorination reaction was established and based on the results the kinetic mechanism of the reaction was investigated. The structure of main products, including 1,3- -dichloropropan-2-ol, 2,3-dichloropropan-1-ol, 3-chloro-1,2-propanediol, 2-chloro- 1,3-propanediol and glycerol was ascertained by gas chromatography-mass spectrometry and the isomers of the products were distinguished. Apidic acid was considered as the best catalyst because of its excellent catalytic effect and high boiling point. The mechanism of the glycerol chlorination reaction was proposed and a new kinetic model was developed. Kinetic equations of the process in the experimental range were obtained by data fitting and the activation energies of each tandem reaction were 30.7, 41.8, 29.4 and 49.5 kJ mol-1, respectively. This study revealed the process and mechanism of the kinetics and provides the theoretical basis for engineering problems.
Three-Dimensional Scapular and Clavicular Kinematics and Scapular Muscle Activity During Retraction Exercises
Authors: Oyama Sakiko , Myers Joseph B. , Wassinger Craig A. , Lephart Scott M.
Published: February 2010

Study Design

Controlled laboratory study.

Objectives

To describe and compare scapular and clavicular kinematics and muscle activity during 6 retraction exercises in young healthy adults (mean ± SD age, 23.2 ± 2.4 years).

Background

Based on the association between shoulder injuries and scapular/clavicular movement, muscle activity during various exercises that target muscles surrounding the scapula have been investigated. However, the scapular and clavicular movements occurring during these exercises remain uninvestigated. Evaluation of the scapular and clavicular kinematics in addition to muscle activity provides additional information that allow clinicians to select exercises that best meet the patient's needs.

Methods

Three-dimensional scapular and clavicular kinematics and scapular muscle activity data were collected while the participants performed 6 scapular retraction exercises. One-way repeated-measures ANOVA and post hoc analyses were used to determine differences in scapular/clavicular kinematics and activation levels of the upper, middle, and lower trapezius and serratus anterior muscles occurring during the exercises.

Results

The general pattern of the kinematics observed during all retraction exercises was scapular external rotation, scapular upward rotation, scapular posterior tilting, clavicular retraction, and clavicular depression. However, the exercises resulted in varying amounts of scapular movement and muscle activity.

Conclusion

Clinicians can select appropriate exercises for their patients based on their need to strengthen specific retractor muscles and to improve specific scapular and clavicular movement patterns, pre-existing conditions, and available range of motion. J Orthop Sports Phys Ther 2010;40(3):169–179.doi:10.2519/jospt.2010.3018
Construct Validity of Muscle Force Tests of the Rotator Cuff Muscles: An Electromyographic Investigation
Authors: Brookham Rebecca L. , McLean Linda , Dickerson Clark R.
Published: February 2010

Background

Manual muscle tests (MMTs) are used in clinical settings to evaluate the function and strength (force-generating capacity) of a specific muscle in a position at which the muscle is believed to be most isolated from other synergists and antagonists. Despite frequent use of MMTs, few electromyographic evaluations exist to confirm the ability of MMTs to isolate rotator cuff muscles.

Objective

This study examined rotator cuff isolation during 29 shoulder muscle force tests (9 clinical and 20 generic tests).

Design

An experimental design was used in this study.

Participants and Measurements

Electromyographic data were recorded from 4 rotator cuff muscles and 10 additional shoulder muscles of 12 male participants. Maximal isolation ratios (mean specific rotator cuff muscle activation to mean activation of the other 13 recorded muscles) defined which of these tests most isolated the rotator cuff muscles.

Results

Three rotator cuff muscles were maximally isolated (obtained highest isolation ratios) within their respective clinical test groups (lateral rotator test group for the infraspinatus and teres minor muscles and abduction test group for the supraspinatus muscle). The subscapularis muscle was maximally isolated equally as effectively within the generic ulnar force and clinical medial rotation groups. Similarly, the supraspinatus and teres minor muscles were isolated equally as effectively in some generic test groups as they were in their respective clinical test groups.

Limitations

Postural artifact in the wire electrodes caused exclusion of some channels from calculations. The grouping of muscle force tests based on test criteria (clinical or generic tests and muscle action) may have influenced which groups most isolated the muscle of interest.

Conclusions

The results confirmed the appropriateness of 9 commonly used clinical tests for isolating rotator cuff muscles, but suggested that several other muscle force tests were equally appropriate for isolating these muscles.
Muscle Activation and Perceived Loading During Rehabilitation Exercises: Comparison of Dumbbells and Elastic Resistance
Authors: Andersen Lars L. , Andersen Christoffer H. , Mortensen Ole S. , Poulsen Otto M. , Bjørnlund Inger Birthe T. , Zebis Mette K.
Published: February 2010

Background

High-intensity resistance training plays an essential role in the prevention and rehabilitation of musculoskeletal injuries and disorders. Although resistance exercises with heavy weights yield high levels of muscle activation, the efficacy of more user-friendly forms of exercise needs to be examined.

Objective

The aim of this study was to investigate muscle activation and perceived loading during upper-extremity resistance exercises with dumbbells compared with elastic tubing.

Design

A single-group, repeated-measures study design was used.

Setting

Exercise evaluation was conducted in a laboratory setting.

Participants

Sixteen female workers (aged 26–55 years) without serious musculoskeletal diseases and with a mean neck and shoulder pain intensity of 7.8 on a 100-mm visual analog scale participated in the study.

Measurements

Electromyographic (EMG) activity was measured in 5 selected muscles during the exercises of lateral raise, wrist extension, and shoulder external rotation during graded loadings with dumbbells (2–7.5 kg) and elastic tubing (Thera-Band, red to silver resistance). The order of exercises and loadings was randomized for each individual. Electromyographic amplitude was normalized to the absolute maximum EMG amplitude obtained during maximal voluntary isometric contraction and exercise testing. Immediately after each set of exercise, the Borg CR10 scale was used to rate perceived loading during the exercise.

Results

Resistance exercise with dumbbells as well as elastic tubing showed increasing EMG amplitude and perceived loading with increasing resistance. At the individually maximal level of resistance for each exercise—defined as the 3 repetitions maximum—normalized EMG activity of the prime muscles was not significantly different between dumbbells (59%–87%) and elastic tubing (64%–86%). Perceived loading was moderately to very strongly related to normalized EMG activity (r=.59–.92).

Limitations

The results of this study apply only for exercises performed in a controlled manner (ie, without sudden jerks or high acceleration).

Conclusions

Comparably high levels of muscle activation were obtained during resistance exercises with dumbbells and elastic tubing, indicating that therapists can choose either type in clinical practice. The Borg CR10 can be a useful aid in estimating intensity of individual rehabilitation protocols.
Image-guided frameless stereotactic biopsy without intraoperative neuropathological examination
Authors: Shooman David , Belli Antonio , Grundy Paul L.
Published: February 2010

Object

Stereotactic biopsy is a safe and effective technique for the diagnosis of brain tumors. The use of intraoperative neuropathological examination has been routinely advocated to increase diagnostic yield, but the procedure lengthens surgical time, may produce false-negative and -positive results, and current biopsy techniques have a very low nondiagnostic rate. Therefore, the authors questioned the need for intraoperative histological evaluation.

Methods

The authors prospectively studied all patients undergoing image-guided biopsy under the care of a single surgeon (P.L.G.) between July 2005 and October 2007. A Stryker neuronavigation system with a trajectory guide was used to plan a single trajectory, and, using a side-cutting biopsy cannula, multiple biopsy samples were taken from between 1 and 4 sites within the tumor. Tissue was inspected macroscopically by the surgeon and was only submitted for neuropathological assessment postoperatively.

Results

One hundred thirty-four biopsies were performed during the study. A positive diagnosis was established in 133 cases (99.3%). One biopsy was negative (0.7%) and postoperative imaging (performed because the tissue was macroscopically normal) demonstrated inaccurate targeting of the lesion. Significant complications were seen in 3 patients (2.2%) who all had preoperative WHO performance scores of III or IV. Two patients suffered delayed deterioration and died due to probable surgical complications—one with thalamic glioblastoma multiforme (GBM) and one with gliomatosis cerebri. One patient with GBM suffered an intracerebral hematoma that was managed conservatively. Postoperative seizures were seen in 4 patients (3%), and 2 patients (1.5%) experienced a transient neurological deficit. Histological diagnosis showed a GBM in 64 cases, Grade III glioma in 19, Grade I or II in 23, metastasis in 10, lymphoma in 13, and other disease in 4. There were 32 patients discharged to home on the same day as surgery. Compared with the authors' previous retrospective audit into 127 biopsies, this technique showed improved diagnostic yield (99.3 vs 94.5%, p = 0.032) with fewer complications (2.2 vs 4.7% [not statistically significant]).

Conclusions

This technique of image-guided biopsy has high diagnostic yield with acceptably low morbidity and may be performed as a day case. Intraoperative neuropathological examination would not have increased the diagnostic yield further in this study, and its routine use may not be necessary. In the authors' department £70,350 (UK)/$114,522 (US) would have been saved by not using intraoperative neuropathology in this series. Therefore, intraoperative neuropathology should no longer be routinely recommended.
An Experimental Evaluation of Boosting Methods for Classification
Authors: Stollhoff R. , Sauerbrei W. , Schumacher M.
Published: February 2010

Objectives: In clinical medicine, the accuracy achieved by classification rules is often not sufficient to justify their use in daily practice. In order to improve classifiers it has become popular to combine single classification rules into a classification ensemble. Two popular boosting methods will be compared with classical statistical approaches.

Methods: Using data from a clinical study on the diagnosis of breast tumors and by simulation we will compare AdaBoost with gradient boosting ensembles of regression trees. We will also consider a tree approach and logistic regression as traditional competitors. In logistic regression we allow to select nonlinear effects by the fractional polynomial approach. Performance of the classifiers will be assessed by estimated misclassification rates and the Brier score.

Results: We will show that boosting of simple base classifiers gives classification rules with improved predictive ability. However, the performance of boosting classifiers was not generally superior to the performance of logistic regression. In contrast to the computer-intensive methods the latter are based on classifiers which are much easier to interpret and to use.

Conclusions: In medical applications, the logistic regression model remains a method of choice or, at least, a serious competitor of more sophisticated techniques. Refinement of boosting methods by using optimized number of boosting steps may lead to further improvement.
Correlation-based Gene Selection and Classification Using Taguchi-BPSO
Authors: Yang C.-S. , Wu K.-C. , Yang C.-H. , Chuang L.-Y.
Published: February 2010

Background: Microarray data with reference to gene expression profiles have provided some valuable results related to a variety of problems, and contributed to advances in clinical medicine. Microarray data characteristically have a high dimension and small sample size, which makes it difficult for a general classification method to obtain correct data for classification. However, not every gene is potentially relevant for distinguishing the sample class. Thus, in order to analyze gene expression profiles correctly, feature (gene) selection is crucial for the classification process, and an effective gene extraction method is necessary for eliminating irrelevant genes and decreasing the classification error rate.

Objective: The purpose of gene expression analysis is to discriminate between classes of samples, and to predict the relative importance of each gene for sample classification.

Method: In this paper, correlation-based feature selection (CFS) and Taguchi-binary particle swarm optimization (TBPSO) were combined into a hybrid method, and the K-nearest neighbor (K-NN) with leave-one-out cross-validation (LOOCV) method served as a classifier for ten gene expression profiles.

Results: Experimental results show that this hybrid method effectively simplifies feature selection by reducing the number of features needed. The classification error rate obtained by the proposed method had the lowest classification error rate for all of the ten gene expression data set problems tested. For six of the gene expression profile data sets a classification error rate of zero could be reached.

Conclusion: The introduced method outperformed five other methods from the literature in terms of classification error rate. It could thus constitute a valuable tool for gene expression analysis in future studies.
Putting Biomedical Ontologies to Work
Authors: Brochhausen M. , Smith B.
Published: February 2010

Objectives: Biomedical ontologies exist to serve integration of clinical and experimental data, and it is critical to their success that they be put to widespread use in the annotation of data. How, then, can ontologies achieve the sort of user-friendliness, reliability, cost-effectiveness, and breadth of coverage that is necessary to ensure extensive usage?

Methods: Our focus here is on two different sets of answers to these questions that have been proposed, on the one hand in medicine, by the SNOMED CT community, and on the other hand in biology, by the OBO Foundry. We address more specifically the issue as to how adherence to certain development principles can advance the usability and effectiveness of an ontology or terminology resource, for example by allowing more accurate maintenance, more reliable application, and more efficient interoperation with other ontologies and information resources.

Results: SNOMED CT and the OBO Foundry differ considerably in their general approach. Nevertheless, a general trend towards more formal rigor and cross-domain interoperability can be seen in both and we argue that this trend should be accepted by all similar initiatives in the future.

Conclusions: Future efforts in ontology development have to address the need for harmonization and integration of ontologies across disciplinary borders, and for this, coherent formalization of ontologies is a prerequisite.
Semantic Interoperability Adheres to Proper Models and Code Systems
Authors: Blobel B. , Oemig F.
Published: February 2010

Objectives: Achieving semantic interoperability requires not only the use of communication standards like HL7 with its underlying models and specifications, but also to constrain those models to instances including permitted attributes, data types, values and code systems. Even the application of both strategies may lead to different modeling approaches and therefore incompatible results, however.

Methods: This paper analyzes the different ways to create a model exemplified at score and assessment systems.

Results: The different approaches have advantages and disadvantages. The presented results allow for transmitting the same basic information facilitating HL7 v2.x and V3 in a way reducing implementation efforts.

Conclusions: Establishing a generic approach to communicate the details of score systems driven by an appropriate set of codes is the best solution for implementers.
Public Participation in Policing: The Impact of Citizen Oversight on the Incidence of Lethal Force over Time in the Largest U.S. Cities
Authors: Ochs Holona LeAnne
Published: February 2010

Does public participation through citizen review boards result in more responsible policing or does public oversight in this form amount to political “interference” resisted by the police? How do the various models of reactive external review impact police use of lethal force in a democratic society? In this article, I argue that citizen participation has the potential to serve the public and the police well when adequately designed and that reactive approaches to external review of the police may not have the intended effect on the incidence of lethal force over time. Specifically, the random effects negative binomial regression reveals that the process audit model of citizen review increases the incidence of lethal force. This study highlights the need for future investigations that focus on the few proactive approaches to citizen review in which the patterns and trends in policies, supervision, and training may offer more lucrative opportunities for participation that generates innovative problem-solving. Future study is also needed to determine the requisite circumstances for fostering mutually beneficial monitoring. The setting for this study on the long-run monitoring role of citizen review is a sample of 30 of the largest U.S. cities from 1994 to 2004.
Situational Aspects of Sexual Offending: Implications for Residence Restriction Laws
Authors: Colombino Nicole , Mercado Cynthia Calkins , Jeglic Elizabeth L.
Published: February 2010

Residence restriction laws, which aim to restrict known sex offenders from residing near child-dense community structures, appear, in part, to be based on the assumption that sex offenders are likely to seek out their victims in public places where children congregate. The current study examined the locations where offenders first came into contact with their victims and the locations where offenders perpetrated offenses. Archival case files ( N = 405) of adult male sex offenders were analyzed to determine the frequency with which sex offenders met their victims and offended in public, semi-public, or private locations. Descriptive analyses revealed that 76.5% of the sex offenders in this sample met their victims in private locations, while 7.7% met their victims in semi-public settings, and 15.8% met their victims in public settings. Similarly, 82.2% of index offenses took place in private locations, while 10.9% and 6.9% occurred in semi-public and public locations, respectively. Given that a minority of offenses occur in public settings, sex offender-specific legislation that restricts offender access to child-dense places may be most effective if tailored narrowly to offender subtypes most likely to seek out victims in public places.
Historia de Arte, Arqueología de la Arquitectura y el telescopio de Galileo
Authors: Arce Sainz Fernando
Published: February 2010

La Historia del Arte y la Arqueología de la Arquitectura son dos disciplinas que convergen en un mismo objeto de estudio: la arquitectura histórica. Sin embargo, una y otra parecen por el momento darse la espalda sin que se aprecien intentos por buscar espacios de diálogo y debate. El encastillamiento conceptual y metodológico da lugar a repliegues defensivos que alimentan posturas irreconciliables. El presente artículo nace como una reflexión que quiere mover a la discusión tanto a historiadores del arte como arqueólogos, no tanto para buscar los puntos de encuentro sino para ver de qué forma se pueden superar los puntos de desencuentro con el objetivo de construir un marco conceptual y metodológico que sea asumible y compartido por unos y otros.
Leyendo los espacios: una aproximación crítica a la sintaxis espacial como herramienta de análisis arqueológico
Authors: Bermejo Tirado Jesús
Published: February 2010

Este trabajo pretende explicar de forma detallada los distintos elementos teóricos y metodológicos que conforman la sintaxis espacial. Se realiza una genealogía de sus bases teóricas como paso previo a la explicación de diversas herramientas analíticas. Éstas se ilustran con una serie de ejemplos históricos concretos. Se plantea un estudio comparativo con otras formas de análisis arquitectónico y arqueológico, del que se deduce una serie de problemas metodológicos. Por último se realiza una reflexión acerca de sus posibilidades interpretativas y se introducen algunas notas destinadas a plantear nuevas perspectivas de uso.
Sistemas complejos y arqueología. Una aproximación teórica al fenómeno urbano
Authors: García Gómez Ismael
Published: February 2010

En este artículo exponemos algunas reflexiones sobre la aplicación del enfoque sistémico en arqueología a partir de la experiencia de nuestra tesis doctoral, que ha tenido como objeto de estudio la ciudad de Vitoria-Gasteiz. Defendemos la idea de que, más allá de las objeciones planteadas desde la arqueología postprocesualista, las nuevas formas de entender los sistemas (Sistemas Emergentes o Complejos), ofrecen una estimulante alternativa para la interpretación en arqueología, alcanzando incluso los significados contextuales.
El castillo de San Romualdo (San Fernando, Cádiz). Aproximación estratigráfica y evolución constructiva
Authors: Utrera Burgal Raquel M. , Tabales Rodríguez Miguel Ángel
Published: February 2010

Presentamos en este artículo los resultados de nuestra investigación arqueológica en el castillo de San Romualdo, el edificio más emblemático de la ciudad de San Fernando y fortaleza defensiva ligada al control del acceso a Cádiz. El análisis estratigráfico de alzados ha permitido conocer la evolución constructiva del edificio, desde sus orígenes hasta la actualidad. Hasta ahora los estudios confirman las conclusiones en cuanto a su datación presentadas en el año 2003, es decir, el castillo, tal y como hoy lo conocemos, es una construcción medieval cristiana, realizada durante la segunda mitad del siglo XIII, con mano de obra mudéjar y con materiales reutilizados de una edificación anterior.
Estudio arqueológico del puente de Pedret (Cercs, Barcelona)
Authors: Vila Carabasa Josep M.
Published: February 2010

El artículo aborda el estudio de la evolución constructiva de un puente de origen medieval, utilizando casi exclusivamente el método estratigráfico tanto en el análisis del subsuelo como en los paramentos de la estructura. El estudio ha permitido documentar la interacción entre el puente y el río con las sucesivas destrucciones y recomposiciones de la estructura, así como las mejoras que cada reparación aportaba respecto de la situación anterior.
Naturally Acquired Antibodies to Plasmodium vivax Duffy Binding Protein (DBP) in Rural Brazilian Amazon
Authors: Souza-Silva Flávia A. , Silva-Nunes Mônica da , Sanchez Bruno A. M. , Ceravolo Isabela P. , Malafronte Rosely S. , Brito Cristiana F. A. , Ferreira Marcelo U. , Carvalho Luzia H.
Published: February 2010

Duffy binding protein (DBP), a leading malaria vaccine candidate, plays a critical role in Plasmodium vivax erythrocyte invasion. Sixty-eight of 366 (18.6%) subjects had IgG anti-DBP antibodies by enzyme-linked immunosorbent assay (ELISA) in a community-based cross-sectional survey in the Brazilian Amazon Basin. Despite continuous exposure to low-level malaria transmission, the overall seroprevalence decreased to 9.0% when the population was reexamined 12 months later. Antibodies from 16 of 50 (36.0%) subjects who were ELISA-positive at the baseline were able to inhibit erythrocyte binding to at least one of two DBP variants tested. Most (13 of 16) of these subjects still had inhibitory antibodies when reevaluated 12 months later. Cumulative exposure to malaria was the strongest predictor of DBP seropositivity identified by multiple logistic regression models in this population. The poor antibody recognition of DBP elicited by natural exposure to P. vivax in Amazonian populations represents a challenge to be addressed by vaccine development strategies.