bluuebunny/crossref_metadata_2025 huggingface dataset:
Inactivation of
bb0184
, Which Encodes Carbon Storage Regulator A, Represses the Infectivity of
Borrelia burgdorferi
Authors: Sze Ching Wooen , Li Chunhao
Published: December 2010

The genome of
Borrelia burgdorferi
, the Lyme disease spirochete, encodes a homolog (the
bb0184
gene product) of the carbon storage regulator A protein (CsrA
Bb
); recent studies reported that CsrA
Bb
is involved in the regulation of several infectivity factors of
B. burgdorferi
. However, the mechanism involved remains unknown. In this report, a

csrA
Bb

mutant was constructed and complemented in an infectious B31A3 strain. Subsequent animal studies showed that the mutant failed to establish an infection in mice, highlighting that CsrA
Bb
is required for the infectivity of
B. burgdorferi
. Western blot analyses revealed that the virulence-associated factors OspC, DbpB, and DbpA were attenuated in the

csrA
Bb

mutant. The Rrp2-RpoN-RpoS pathway (σ
54
-σ
S
sigma factor cascade) is a central regulon that governs the expression of
ospC
,
dbpB
, and
dbpA
. Further analyses found that the level of RpoS was significantly decreased in the mutant, while the level of Rrp2 remained unchanged. A recent study reported that the overexpression of BB0589, a phosphate acetyl-transferase (Pta) that converts acetyl-phosphate to acetyl-coenzyme A (CoA), led to the inhibition of RpoS and OspC expression, suggesting that acetyl-phosphate is an activator of Rrp2. Along with this report, we found that CsrA
Bb
binds to the leader sequence of the
bb0589
transcript and that the intracellular level of acetyl-CoA in the

csrA
Bb

mutant was significantly increased compared to that of the wild type, suggesting that more acetyl-phosphate was being converted to acetyl-CoA in the mutant. Collectively, these results suggest that CsrA
Bb
may influence the infectivity of
B. burgdorferi
via regulation of acetate metabolism and subsequent activation of the Rrp2-RpoN-RpoS pathway.
Use of aDictyosteliumModel for Isolation of Genetic Loci Associated with Phagocytosis and Virulence inKlebsiella pneumoniae
Authors: Pan Yi-Jiun , Lin Tzu-Lung , Hsu Chun-Ru , Wang Jin-Town
Published: December 2010

Phagocytosis resistance is an important virulence factor inKlebsiella pneumoniae.Dictyosteliumhas been used to study the interaction between phagocytes and bacteria because of its similarity to mammalian macrophages. In this study, we used aDictyosteliummodel to investigate genes for resistance to phagocytosis in NTUH-K2044, a strain ofK. pneumoniaecausing pyogenic liver abscess that is highly resistant to phagocytosis. A total of 2,500 transposon mutants were screened by plaque assay, and 29 of them permitted phagocytosis byDictyostelium. In the 29 mutants, six loci were identified; three were capsular synthesis genes. Of the other three, one was related to carnitine metabolism, one encoded a subunit of protease (clpX), and one encoded a lipopolysaccharide O-antigen transporter (wzm). Deletion and complementation of these genes showed that only ΔclpXand Δwzmmutants became susceptible toDictyosteliumphagocytosis, and their complementation restored the phagocytosis resistance phenotype. These two mutants were also susceptible to phagocytosis by human neutrophils and revealed attenuated virulence in a mouse model, implying that they play important roles in the pathogenesis ofK. pneumoniae. Furthermore, we demonstrated thatclpP, which exists in an operon withclpX, was also involved in resistance to phagocytosis. The transcriptional profile of ΔclpXwas examined by microarray analysis and revealed a 3-fold lower level of expression of capsular synthesis genes. Therefore, we have identified genes involved in resistance to phagocytosis inK. pneumoniaeusingDictyostelium, and this model is useful to explore genes associated with resistance to phagocytosis in heavily encapsulated bacteria.
ygs
Is a Novel Gene That Influences Biofilm Formation and the General Stress Response of
Staphylococcus epidermidis
Authors: Wang Xing , Niu Chen , Sun Gang , Dong Dandan , Villaruz Amer E. , Li Min , Wang Decheng , Wang Jianping , Otto Michael , Gao Qian
Published: December 2010

Infections caused by the nosocomial pathogen
Staphylococcus epidermidis
frequently develop on implanted medical devices and involve biofilm formation. Biofilms are surface-attached microbial communities that show increased resistance to drug treatment and mechanisms of innate host defense. In this study, a mutant library of the clinical isolate
S. epidermidis
1457 was constructed using mariner-based transposon mutagenesis. About a thousand mutants were screened, and 12 mutants were identified as significantly defective in biofilm formation. We focused on a mutant in which the transposon had inserted in a gene with unknown function,
SERP0541
, which is annotated as a gene encoding a GSP13-like general stress response protein. The gene was named
ygs
(encoding an unknown

g

eneral

s

tress protein). Various stresses, including heat, pH, high osmolarity, and ethanol affected the survival of the
ygs
mutant to a significantly higher degree than the wild-type strain and led to increased expression of
ygs
. Furthermore, synthesis of polysaccharide intercellular adhesin (PIA) and transcription of the PIA biosynthetic operon were significantly decreased in the
ygs
mutant. These results are in accordance with the putative involvement of
ygs
in stress-response gene regulation and indicate that
ygs
influences biofilm development by controlling PIA-dependent biofilm accumulation. Moreover,
ygs
had a significant impact on the formation of biofilms and metastatic disease in two catheter-related rat infection models. Our study shows that the
ygs
gene controls
S. epidermidis
biofilm accumulation and stress resistance, representing a key regulator of both structural and physiological biofilm characteristics with a significant impact on biofilm-associated infection.
AnIn VivoHigh-Throughput Screening Approach Targeting the Type IV Secretion System Component VirB8 Identified Inhibitors ofBrucella abortus2308 Proliferation
Authors: Paschos Athanasios , den Hartigh Andreas , Smith Mark A. , Atluri Vidya L. , Sivanesan Durga , Tsolis Renée M. , Baron Christian
Published: December 2010

As bacterial pathogens develop resistance against most currently used antibiotics, novel alternatives for treatment of microbial infectious diseases are urgently needed. Targeting bacterial virulence functions in order to disarm pathogens represents a promising alternative to classical antibiotic therapy. Type IV secretion systems, which are multiprotein complexes in the cell envelope that translocate effectors into host cells, are critical bacterial virulence factors in many pathogens and excellent targets for such “antivirulence” drugs. The VirB8 protein from the mammalian pathogenBrucellawas chosen as a specific target, since it is an essential type IV secretion system component, it participates in multiple protein-protein interactions, and it is essential for the assembly of this translocation machinery. The bacterial two-hybrid system was adapted to assay VirB8 interactions, and a high-throughput screen identified specific small-molecule inhibitors. VirB8 interaction inhibitors also reduced the levels of VirB8 and of other VirB proteins, and many of them inhibitedvirBgene transcription inBrucella abortus2308, suggesting that targeting of the secretion system has complex regulatory effectsin vivo. One compound strongly inhibited the intracellular proliferation ofB. abortus2308 in a J774 macrophage infection model. The results presented here show thatin vivoscreens with the bacterial two-hybrid assay are suited to the identification of inhibitors ofBrucellatype IV secretion system function.
Development of a Secondary Immune Response toMycobacterium tuberculosisIs Independent of Toll-Like Receptor 2
Authors: McBride Amanda , Bhatt Kamlesh , Salgame Padmini
Published: December 2010

Published work indicates that the contribution of Toll-like receptor 2 (TLR2) to host resistance during acuteMycobacterium tuberculosisinfection is marginal. However, in these studies, TLR2 participation in the memory immune response toM. tuberculosiswas not determined. The substantialin vitroevidence thatM. tuberculosisstrongly triggers TLR2 on dendritic cells and macrophages to bring about either activation or inhibition of antigen-presenting cell (APC) functions, along with accumulating evidence that memory T cell development can be calibrated by TLR signals, led us to question the role of TLR2 in host resistance to secondary challenge withM. tuberculosis. To address this question, a memory immunity model was employed, and the response of TLR2-deficient (TLR2 knockout [TLR2KO]) mice following a secondary exposure toM. tuberculosiswas compared to that of wild-type (WT) mice based on assessment of the bacterial burden, recall response, phenotype of recruited T cells, and granulomatous response. We found that upon rechallenge withM. tuberculosis, both WT and TLR2KO immune mice displayed similarly enhanced resistance to infection in comparison to their naïve counterparts. The frequencies ofM. tuberculosis-specific gamma interferon (IFN-γ)-producing T cells, the phenotypes of recruited T cells, and the granulomatous responses were also similar between WT and TLR2KO immune mice. Together, the findings from this study indicate that TLR2 signaling does not influence memory immunity toM. tuberculosis.
Model of Polymicrobial Peritonitis That Induces the Proinflammatory and Immunosuppressive Phases of Sepsis
Authors: Barrera Gabriela , Landoni Verónica , Martire-Greco Daiana , Chiarella Paula , Meiss Roberto , Gómez Sonia A. , Alves-Rosa Fernanda , Rearte Barbara , Isturiz Martín , Palermo Marina S. , Fernández Gabriela C.
Published: December 2010

Severe sepsis is associated with early release of inflammatory mediators that contribute to the morbidity and mortality observed during the first stages of this syndrome. Although sepsis is a deadly, acute disease, high mortality rates have been observed in patients displaying evidence of sepsis-induced immune deactivation. Although the contribution of experimental models to the knowledge of pathophysiological and therapeutic aspects of human sepsis is undeniable, most of the current studies using animal models have focused on the acute, proinflammatory phase. We developed a murine model that reproduces the early acute phases but also the long-term consequences of human sepsis. We induced polymicrobial acute peritonitis (AP) by establishing a surgical connection between the cecum and the peritoneum, allowing the exit of intestinal bacteria. Using this model, we observed an acute phase with high mortality, leukopenia, increased interleukin-6 levels, bacteremia, and neutrophil activation. A peak of leukocytosis on day 9 or 10 revealed the persistence of the infection within the lung and liver, with inflammatory hepatic damage being shown by histological examination. Long-term (20 days) derangements in both innate and adaptive immune responses were found, as demonstrated by impaired systemic tumor necrosis factor alpha production in response to an inflammatory stimulus; a decreased primary humoral immune response and T cell proliferation, associated with an increased number of myeloid suppressor cells (Gr-1+CD11b+) in the spleen; and a low clearance capacity. This model provides a good approach to attempt novel therapeutic interventions directed to augmenting host immunity during late sepsis.
Leptospira santorosai
Serovar Shermani Detergent Extract Induces an Increase in Fibronectin Production through a Toll-Like Receptor 2-Mediated Pathway
Authors: Tian Ya-Chung , Hung Cheng-Chieh , Li Yi-Jung , Chen Yung-Chang , Chang Ming-Yang , Yen Tzung-Hai , Hsu Hsiang-Hao , Wu Mai-Szu , Phillips Aled , Yang Chih-Wei
Published: December 2010

Leptospirosis can activate inflammatory responses through Toll-like receptors (TLRs) and may cause renal tubulointerstitial fibrosis characterized by the accumulation of extracellular matrix (ECM). We have previously demonstrated that
Leptospira santorosai
serovar Shermani detergent extract stimulates ECM accumulation
in vitro
. The aim of this study was to examine the mechanistic basis of these previous observations and, in particular, to examine the potential involvement of TLRs. The addition of serovar Shermani detergent extract led to an increase in fibronectin gene expression and production. Inhibition of TLR2 but not TLR4 expression abrogated serovar Shermani detergent extract-mediated increases in fibronectin production. This response was also blocked by the knockdown of the gene expression of the TLR2 downstream transducers myeloid differentiation factor 88 (MyD88) and tumor necrosis factor receptor-associated factor 6 (TRAF6). Serovar Shermani detergent extract also activated nuclear factor-κB, and its inhibition by curcumin-attenuated serovar Shermani detergent extract induced increases in fibronectin production. These effects were also mimicked by the specific TLR2 agonist, Pam(3)CsK(4), a response that was also abrogated by the knockdown of MyD88 and TRAF6. Similarly, the administration of live leptospires to cells also induced fibronectin production that was blocked by inhibition of TLR2 and MyD88 expression. In conclusion, serovar Shermani detergent extract can induce fibronectin production through the TLR2-associated cascade, providing evidence of an association between TLRs and leptospirosis-mediated ECM deposition.
Using Flow Cytometry to Measure Phagocytic Uptake in Earthworms
Authors: Fuller-Espie Sheryl L.
Published: December 2010

This laboratory module familiarizes students with flow cytometry while acquiring quantitative reasoning skills during data analysis. Leukocytes, also known as coelomocytes (including hyaline and granular amoebocytes, and chloragocytes), from
Eisenia hortensis
(earthworms) are isolated from the coelomic cavity and used for phagocytosis of fluorescent
Escherichia coli
. Students learn how to set up
in vitro
cellular assays and become familiar with theoretical principles of flow cytometry. Histograms based on fluorescence and scatter properties combined with gating options permit students to restrict their analyses to particular subsets of coelomocytes when measuring phagocytosis, a fundamentally important innate immune mechanism used in earthworms. Statistical analysis of data is included in laboratory reports which serve as the primary assessment instrument.
Studying Simple and Complex Traits Using Pedigrees Produced From a Large Database
Authors: Emmons Cheryld L.
Published: December 2010

Students in genetics classes become familiar with interpreting pedigrees for modes of inheritance of single-gene traits. Non-majors’ genetics courses often have students produce pedigrees of their own families. This exercise provides students with an extensive database, including over 50 families, from which they are asked to produce pedigrees as evidence in support of or refuting suggested models of inheritance for simple traits. Students are also asked to propose modes of inheritance for complex human traits based on pedigrees that they produce from the database. The people in the database are real and include their own families. This makes the exercise more real and personal for the students.
Coliforms Everywhere! Using Microbiology to Teach the Scientific Method
Authors: Cisar Cindy R. , de Banzie John S.
Published: December 2010

The scientific method is a fundamental concept in science. In this exercise the scientific method is taught as a hands-on investigative laboratory experience. Students generate a hypothesis concerning the environmental distribution of coliforms, design and execute an experimental test of that hypothesis, and analyze the resulting data. The exercise is safe and straightforward. It is appropriate for use in undergraduate laboratory courses for science majors and secondary school students and undergraduate non-majors with the appropriate mathematical backgrounds. Students learn both the process by which science progresses, as well as more advanced concepts in microbiology and statistics.
Multiple Benefits Derived from a Peer Teacher Program in Two Undergraduate Microbiology Lab Courses
Authors: Sailer Frances C. , Melvold Roger W. , Hosford Charles C.
Published: December 2010

A peer teaching program was implemented to alleviate the problem of a limited number of lab instructors attempting to teach large numbers of students in two different undergraduate microbiology lab courses. The benefit of having peer teachers was immediately obvious to the lab instructors, faculty and staff who were responsible for conducting the labs, but it was soon evident that there were also benefits for everyone else involved in the program. The students enrolled in the labs reported that having peer teachers in the lab enhanced their learning, and they felt comfortable receiving help from a peer teacher who had recently completed the course. The peer teachers discovered that they gained valuable experience and confidence while teaching other students, and they appreciated the chance to gain hands-on experience. The lab instructors received the qualified help they needed in order to give more individual attention to the large numbers of students in the labs. The feedback from this program has been positive from everyone involved.
The Use of Popular Fiction to Present a Professional Scientific Career to High School Students
Authors: Durand Caylib , Ramón-García Santiago
Published: December 2010

In a previous Tips & Tools article, Patricia J. Baynham advocated for the introduction of science to students by hosting scientists in classrooms. We approached the issue from a different perspective. Since the ability of scientists to demonstrate science could be hampered with limited time and classroom resources, we proposed to introduce students to a professional and active scientific environment for a one-day outreach program. Our goal was to give students hands-on training, mentorship, career information, and an opportunity to ask questions to facilitate a possible career choice in research.

Briefly, the “CSI at the LSI” outreach program (LSI, Life Sciences Institute), based on the popular fiction “Crime Scene Investigation” (CSI) TV show, was a murder mystery involving a plot with real characters (grad students, postdocs, and professors) to generate a fun and interactive learning environment. The students carried out experiments using modern scientific techniques to collect “evidence.” At the end of the day, they share the results to identify the suspect.
A Family Review of a Fran Balkwill Children’s Book about GermsGerm Zappers by	BalkwillFran, illustrations by	RolphMic (	2002).	Cold Spring Harbor Press,	Woodbury, NY.	32 pages.
Authors: De Souza-Hart Janet
Published: December 2010

Review of:
Germ Zappers
by Fran Balkwill, illustrations by Mic Rolph (2002) . Cold Spring Harbor Press, Woodbury, NY. 32 pages.
Advice for the Road: a Memoir and Practical Advice Drawn from a Career of Six DecadesA Scientist’s Survival Guide by	HaasGerhard J. (	2010).	Royal Fireworks Press,	Unionville, NY.	140 pages.
Authors: Huang Jean J.
Published: December 2010

Review of:
A Scientist’s Survival Guide
by Gerhard J. Haas (2010) . Royal Fireworks Press, Unionville, NY. 140 pages.
Understanding Undergraduates’ Problem-Solving Processes
Authors: Nehm Ross H.
Published: December 2010

Fostering effective problem-solving skills is one of the most longstanding and widely agreed upon goals of biology education. Nevertheless, undergraduate biology educators have yet to leverage many major findings about problem-solving processes from the educational and cognitive science research literatures. This article highlights key facets of problem-solving processes and introduces methodologies that may be used to reveal how undergraduate students perceive and represent biological problems. Overall, successful problem-solving entails a keen sensitivity to problem contexts, disciplined internal representation or modeling of the problem, and the principled management and deployment of cognitive resources. Context recognition tasks, problem representation practice, and cognitive resource management receive remarkably little emphasis in the biology curriculum, despite their central roles in problem-solving success.
The Use of Personal Narrative in Classroom Case Study Analysis to Improve Long-term Knowledge Retention and Cultivate Professional Qualities in Allied Health Students
Authors: Young Linda M. , Anderson Rodney P.
Published: December 2010

This study evaluated the use of two different case study formats (clinically-oriented cases versus personally-oriented cases) to determine which was most effective in promoting long-term retention of clinically significant microbiology concepts, developing patient empathy, improving comprehension of patient compliance problems, and facilitating student understanding of transcultural health care concerns. The analysis was conducted in multiple sections of three different introductory microbiology classes targeting specific cohorts: nursing students, pharmacy students and other allied health students (pre-med, pre-PA, CLS, etc.). Retention of course content was determined by evaluation of multiple-choice and short answer examinations at least three weeks after completing case studies. Evaluation of patient empathy, understanding of patient compliance issues and transcultural health care concerns were determined via student surveys. The results of the study indicated that personalized cases significantly improved long-term retention of course content. In addition, student responses indicated that personalized case studies were more effective in developing patient empathy and aiding students in understanding issues patients have with complying with treatment recommendations. Finally, personalized case studies were effective tools for introducing students to the challenges of transcultural health care.
Building Microbial MachinesThe International Genetically Engineered Machines website: http://www.2009.igem.org
Authors: Scheifele Lisa Z.
Published: December 2010

Review of:
The International Genetically Engineered Machines website.
Efficacy of Role Play in Concert with Lecture to Enhance Student Learning of Immunology
Authors: Elliott Samantha L.
Published: December 2010

Despite numerous reports that active learning increases student understanding, many barriers still exist that prevent faculty from shedding the traditional passive lecture and adopting active learning strategies in the classroom. This study looks at the use of role play as an active learning technique to convey new material, or as reinforcement to traditional lecture. A pre- and post-test survey was utilized to determine student learning gains, along with an anonymous survey to determine student attitudes about role play. Student learning gains are similar regardless of class size, role-playing participation or learning style, and reflect an increase in lower order cognition. Attitudes and learning gains indicate role play is preferable as a reinforcement technique, although the order does not matter if both lecture and role play are utilized to convey information. These data provide insight into the best practices of role-playing implementation in concert with traditional lecture format.
The Sci-Fi Microbe: Reinforcing Understanding of Microbial Structures and their Significance Through a Creative Writing Exercise
Authors: Dolberry Adrienne A.
Published: December 2010

By blending storytelling with topics in biology, a fun activity can be created for students to strengthen their scientific knowledge. The “Sci-Fi Microbe” writing assignment lets students create an altered version of a known microorganism, and write a story describing an unusual observation that leads the characters discovery of their new microorganism.

The Sci-Fi Microbe exercise is appropriate for any microbiology course where the instructor has previously reviewed structures, metabolism, and growth conditions of microorgan-isms. Since students are responsible for developing and writing their own stories, the activity allows for the instructor to assess students’ understanding in an exercise where they are required to articulate the connection of the microbe to its environment – thereby discouraging simple memorization of facts
Chemotaxis on the Move – Active Learning Teaching Tool
Authors: Williams Ann H.
Published: December 2010

In Microbiology courses, concepts such as chemotaxis can be difficult to visualize for students. Described here is a short visual playacting activity where students simulate E.coli moving towards an attractant source using a biased random walk. This short interactive activity is performed in the lecture course of General Microbiology that contains mostly Biology major juniors or seniors prior to the lecture on the subject of chemotaxis and flagellar movements. It is utilized to help students (class of 30–40) understand and visualize the process of chemotaxis and the concepts of random walk, biased random walk, runs, tumbles and directed movement of flagella in response to attractants and repellents.
A Review of
Inside the Outbreaks: The Elite Medical Detectives of the Epidemic Intelligence Service
Inside the Outbreaks: The Elite Medical Detectives of the Epidemic Intelligence Serivce;	PendergrastMark; (	2010).	Houghton Mifflin Harcourt.	Boston.	432 pages.
Authors: Smith Tara C.
Published: December 2010

Review of:
Inside the Outbreaks: The Elite Medical Detectives of the Epidemic Intelligence Serivce ;
Mark Pendergrast; (2010). Hough-ton Mifflin Harcourt. Boston. 432 pages.
A Review of
Microbiology: an Evolving Science
Microbiology: an Evolving Science.	1st ed.SlonczewskiJoan L. and	FosterJohn W.; (	2008).	W.W. Norton and Company,	New York.	1280 pages.
Authors: Irani Vida R.
Published: December 2010

Review of:
Microbiology: an Evolving Science.
1 st ed. Joan L. Slonczewski and John W. Foster; (2008) . W.W. Norton and Company, New York. 1280 pages.
The Impending Crisis
Authors: Kaplan Raymond L. , Burgess Thomas E.
Published: December 2010

When you are ill and consult a physician for his or her expertise, many times laboratory testing is part of the clinical workup. This testing is critical to the physician’s ability to diagnose the patient’s condition. What if testing was not available …
because there was no one to do the testing?
Although seemingly far-fetched, this scenario could play itself out in the next ten years due to an impending manpower crisis in laboratory medicine. The profession of Medical Technology, also known as Clinical Laboratory Science, is experiencing a shortage of qualified individuals for a variety of reasons – not the least of which is the closure of almost 70% of the schools teaching this critical profession. Health care workers (HCW) rely on accurate and timely clinical laboratory results in order to make decisions for their patients. Because ∼ 70% of patient care decisions are based on clinical laboratory results, it is important to have a well-trained supply of laboratory professionals. This article will give an overview of the situation and the possible causes of this shortage, and pose challenges to our profession as to how this crisis can be averted. Visibility of this profession must be a prime focus of this effort in order for the population in general to be aware of the role Clinical Laboratory Scientists play in the health care consortium. This effort should begin early in the educational process, potentially as early as Middle School (junior high school), bringing awareness of the profession not only to students but to educators as well.
Journal Watch
Authors: Herzog Jennifer A.
Published: December 2010

The Journal Watch section highlights published journal articles which discuss recent developments and new technology used in microbiology and related fields.
Comparison study of growth plate fusion using MRI versus plain radiographs as used in age determination for exclusion of overaged football players
Authors: George John , Nagendran Jayaselvi , Azmi Khairul
Published: December 2010

Background

MRI of distal radius fusion is currently being used in the U17 World Cup to exclude overaged players. Developing countries that cannot afford to perform MRI on their players are using plain radiographs based on the same MRI criteria of fusion.

Objective

The aim of this study is to compare the grade of fusion of the left wrist distal radial growth plate between MRI and plain radiographs.

Methods

150 healthy male football players were grouped into five age groups ranging from 15 to 19 years old. Each participant had coronal T1-weighted MRI and plain radiograph of the left wrist. The degree of distal radius fusion was rated randomly by three radiologists using a six-stage grading system proposed by the FIFA Research Centre.

Results

MRI assessment of distal radial growth plate fusion has good correlation with plain radiograph fusion (r=0.949). The mean of x-ray grading is higher than the MRI grading in the 15, 16, 17, 18 and 19 years old age groups with p=0.443, 0.001, 0.009, <0.001 and 0.003, respectively, using Wilcoxon signed ranked test. Intraobserver and interobserver correlations were high (r=0.9). T1 MRI correlation with chronological age (r=0.771) was close to plain radiographs (r=0.821) with p value of <0.001.

Conclusion

This article is of major importance as it is the first to show that x-rays significantly overrate the grading of fusion in this age group and therefore should not be used to exclude overaged players as is occurring now to the distress of many genuinely eligible players.
A NONPARAMETRIC URN-BASED APPROACH TO INTERACTING FAILING SYSTEMS WITH AN APPLICATION TO CREDIT RISK MODELING
Authors: CIRILLO PASQUALE , HÜSLER JÜRG , MULIERE PIETRO
Published: December 2010

In this paper we propose a new nonparametric approach to interacting failing systems (FS), that is systems whose probability of failure is not negligible in a fixed time horizon, a typical example being firms and financial bonds. The main purpose when studying a FS is to calculate the probability of default and the distribution of the number of failures that may occur during the observation period. A model used to study a failing system is defined default model. In particular, we present a general recursive model constructed by the means of interacting urns. After introducing the theoretical model and its properties we show a first application to credit risk modeling, showing how to assess the idiosyncratic probability of default of an obligor and the joint probability of failure of a set of obligors in a portfolio of risks, that are divided into reliability classes.
BETTER CONFIDENCE INTERVALS FOR IMPORTANCE SAMPLING
Authors: SAK HALIS , HÖRMANN WOLFGANG , LEYDOLD JOSEF
Published: December 2010

It is well known that for highly skewed distributions the standard method of using the t statistic for the confidence interval of the mean does not give robust results. This is an important problem for importance sampling (IS) as its final distribution is often skewed due to a heavy tailed weight distribution. In this paper, we first explain Hall's transformation and its variants to correct the confidence interval of the mean and then evaluate the performance of these methods for two numerical examples from finance which have closed-form solutions. Finally, we assess the performance of these methods for credit risk examples. Our numerical results suggest that Hall's transformation or one of its variants can be safely used in correcting the two-sided confidence intervals of financial simulations.
VANNA-VOLGA METHODS APPLIED TO FX DERIVATIVES: FROM THEORY TO MARKET PRACTICE
Authors: BOSSENS FRÉDÉRIC , RAYÉE GRÉGORY , SKANTZOS NIKOS S. , DEELSTRA GRISELDA
Published: December 2010

We study Vanna-Volga methods which are used to price first generation exotic options in the Foreign Exchange market. They are based on a rescaling of the correction to the Black–Scholes price through the so-called "probability of survival" and the "expected first exit time". Since the methods rely heavily on the appropriate treatment of market data we also provide a summary of the relevant conventions. We offer a justification of the core technique for the case of vanilla options and show how to adapt it to the pricing of exotic options. Our results are compared to a large collection of indicative market prices and to more sophisticated models. Finally we propose a simple calibration method based on one-touch prices that allows the Vanna-Volga results to be in line with our pool of market data.
STRINGS OF GROUP ENDOMORPHISMS
Authors: DIKRANJAN DIKRAN , GIORDANO BRUNO ANNA , VIRILI SIMONE
Published: December 2010

Recently the strings and the string number of self-maps were used in the computation of the algebraic entropy of specific abelian group endomorphisms. We introduce two special kinds of strings, and their relative string numbers. We show that a dichotomy holds for all these three string numbers; in fact, they admit only zero and infinity as values on abelian group endomorphisms.
SS-QUASINORMAL SUBGROUPS OF FINITE GROUPS
Authors: ZHAO TAO , LI XIANHUA
Published: December 2010

A subgroup H of a finite group G is said to be SS-quasinormal in G if there exists a supplement B of H in G such that H is permutable with every Sylow subgroup of B. In this paper, we get some new characterizations of supersolvability and p-nilpotency of G by assuming some subgroups of prime power order of G are SS-quasinormal.
ON MINIMAL SUBGROUP COVERINGS OF SOME AFFINE PRIMITIVE PERMUTATION GROUPS
Authors: JAFARIAN AMIRI SEYYED MAJID
Published: December 2010

A cover for a group G is a collection of proper subgroups of G whose union is G. Cohn defined σ(G) to be the least integer m such that G is the union of m proper subgroups. Determining σ is an open problem for most non-solvable groups. We obtain σ(G) for some affine primitive groups.
DEFINING EQUATIONS OF THE REES ALGEBRA OF CERTAIN PARAMETRIC SURFACES
Authors: HOFFMAN J. WILLIAM , WANG HAOHAO
Published: December 2010

Let f0, f1, f2, f3 be linearly independent nonzero homogeneous polynomials in the standard ℤ-graded ring R ≔ 𝕂[s, t, u] of the same degree d, and gcd (f0, f1, f2, f3) = 1. This defines a rational map ℙ2 → ℙ3. The Rees algebra Rees (I) = R ⊕ I ⊕ I2 ⊕ ⋯ of the ideal I = 〈f0, f1, f2, f3〉 is the graded R-algebra which can be described as the image of the R-algebra homomorphism h: R[x, y, z, w ] → Rees (I). This paper discusses one result concerning the structure of the kernel of the map h when I is a saturated local complete intersection ideal with V(I) ≠ ∅ and μ-basis of degrees (1,1,d - 2).
GENDER DIFFERENCES IN ENTREPRENEURIAL INTENTIONS: EVIDENCE FROM BULGARIA
Authors: YORDANOVA DESISLAVA I. , TARRAZON MARIA-ANTONIA
Published: December 2010

Despite the increasing interest in researching female entrepreneurship, little is known about gender differences in pre-venture process and the variables that mediate the relationship between gender and entrepreneurial intentions. The purpose of this study is to provide a conceptual framework for understanding gender differences in entrepreneurial intentions. Using this framework, we explore gender effects on entrepreneurial intentions and identify factors that may account for the gender gap in entrepreneurial intentions in a sample of Bulgarian university students. Our results show that women have lower entrepreneurial intentions than men. The gender effect on entrepreneurial intentions is fully mediated by perceived behavioral control and partially mediated by perceived subjective norms and attitudes toward entrepreneurship. Policy measures designed to encourage female start-ups should be directed at attitudes, subjective norms, perceived behavioral control and the link between entrepreneurial intentions and behavior among women.
ESTABLISHED BUSINESS OWNERS' SUCCESS: INFLUENCING FACTORS
Authors: AYALA CALVO JUAN CARLOS , MANZANO GARCÍA GUADALUPE
Published: December 2010

This study investigates the effects of the following factors on established business owners' success. First, the human capital of the entrepreneur is examined (education, experience, locus of internal control, need for achievement and resilience). Second, the characteristics of the firm with reference to the initial financial resources, number of partners, frequency and breadth of external communication are taken into consideration, and finally, factors relevant to the conception and development of the firm are studied. To achieve our objective, we have used a structural equation modeling technique (Partial Least Squares -PLS-) to estimate a path model with latent variables. Although all the latent variables have a positive impact on established business owners' success, our findings show clearly that the size of the company is an important moderating factor when explaining established business owners' success. The variables in which this effect is most evident are that of education and resilience. If we do not take the size of the company into consideration, the variables that help explain the success of established business owners are, in order of decreasing importance, experience, a favorable perception of the business environment and the resilience of the entrepreneur.
A NOVEL TWO-STAGE GENETIC ALGORITHM FOR IMAGE RECONSTRUCTION OF ELECTRICAL RESISTANCE TOMOGRAPHY
Authors: ASGARIFAR SANAZ , FROUNCHI JAVAD , ZARIFI MOHAMMAD HOSSIEN , MAHDIZADEH AMIN
Published: December 2010

In this paper, we present a combined GA-ERT method based on two-stage genetic algorithm for image reconstruction in electrical resistance tomography (ERT). Image reconstruction in ERT is an ill-posed inverse problem and we have replaced the reverse solver by a two-stage optimization algorithm. The first stage of GA-ERT is reach to an approximate shape and location of the object. Also in this stage, we proposed a new electrode arrangement for ERT forward solver to reduce the process time of the forward problem. In the second stage, the GA employs result of the first stage as an initial population instead of a random group. Therefore with the local zoom, the GA can be employed to obtain the shape and location of the object more precisely. Experimental results of numerically solved ERT by the GA are also presented and compared to those obtained by other more established inversion methods such as modified Newton–Raphson (mNR) and RES2DINV program which is a standard 2-D resistivity inversion program. Results show that the proposed method can efficiently improve the ill-posed condition of ERT image reconstruction problem and can superiorly enhance the quality of ERT images.
CONTINUOUS NEURAL NETWORKS APPLIED TO IDENTIFY A CLASS OF UNCERTAIN PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS
Authors: FUENTES R. , POZNYAK A. , CHAIREZ I. , FRANCO M. , POZNYAK T.
Published: December 2010

There are a lot of examples in science and engineering that may be described using a set of partial differential equations (PDEs). Those PDEs are obtained applying a process of mathematical modeling using complex physical, chemical, etc. laws. Nevertheless, there are many sources of uncertainties around the aforementioned mathematical representation. It is well known that neural networks can approximate a large set of continuous functions defined on a compact set. If the continuous mathematical model is incomplete or partially known, the methodology based on Differential Neural Network (DNN) provides an effective tool to solve problems on control theory such as identification, state estimation, trajectories tracking, etc. In this paper, a strategy based on DNN for the no parametric identification of a mathematical model described by parabolic partial differential equations is proposed. The identification solution allows finding an exact expression for the weights' dynamics. The weights adaptive laws ensure the "practical stability" of DNN trajectories. To verify the qualitative behavior of the suggested methodology, a no parametric modeling problem for a couple of distributed parameter plants is analyzed: the plug-flow reactor model and the anaerobic digestion system. The results obtained in the numerical simulations confirm the identification capability of the suggested methodology.
KNEE KINEMATICS SIMULATION AND COMPARATIVE FLEXION ANGLE ANALYSIS OF RECONSTRUCTED KNEE VERSUS STANDARD ARTIFICIAL KNEE VERSUS HIGH FLEXION ARTIFICIAL KNEE
Authors: SIVARASU SUDESH , PRASANNA SAM , MATHEW LAZAR
Published: December 2010

Knee simulation has been used as the primary tool in the estimation of knee flexion–extension levels for many years. This paper discusses the suitability of AdamsView simulation tool for estimating the flexion–extension angles in the knee joint, i.e. three versions namely: 3D reconstructed knee joint, standard artificial knee joint and artificial high flexion knee joint. The high flexion artificial knee joint model reaches a maximum flexion up to 120.2°. Whereas the standard knee Joint gets about 84.6°. However, the 3D reconstructed knee joint was capable of producing 134.4°. Thus the usage of the mechanical simulation tools in the medical applications has been proved once again.
Program Adherence and Effectiveness of a Commercial Nutrition Program: The Metabolic Balance Study
Authors: Meffert Cornelia , Gerdes Nikolaus
Published: December 2010

Objective. To assess the effectiveness of a commercial nutrition program in improving weight, blood lipids, and health-related quality of life (HRQOL).Methods. Prospective observational study with followup after 1, 3, 6, and 12 months with data from questionnaires and blood samples.Subjects. After 12 months, we had data from 524 subjects (= 60.6% of the initial samples). 84.1% of the subjects were women. The average BMI at baseline was 30.3 (SD = 5.7).Results. After 12 months, the average weight loss was 6.8 kg (SD = 7.1 kg). Program adherence declined over time but was still high after 12 months and showed a positive linear correlation with weight loss. Relevant blood parameters as well as HRQOL improved significantly.Conclusion. After 12 months, nearly two thirds of the samples had achieved >5% reduction of their initial weights. The high degree of program adherence is probably due to personal counseling and individually designed nutrition plans provided by the program.
Dental Laboratory Production of Prosthetic Restorations in a Population in Sofia, Bulgaria: A Descriptive Study
Authors: Damyanov Nikola D. , Witter Dick J. , Gerritsen Anneloes E. , Creugers Nico H. J.
Published: December 2010

Objective. To describe prosthodontic production related to mutilated dentitions in Sofia, Bulgaria.Methods. Prosthodontic production from 5 dental laboratories was recorded during a 14-day period. Production was related to dentitions as noted from casts. Dentitions were classified as edentulous, interrupted/reduced, slightly interrupted, shortened, and complete. The representativeness of the laboratory sample was verified trough comparison with a Sofia population sample using proportions of crowned or replaced teeth per dental region.Results. The total production consisted of 243 crowns, 16 post and cores, 82 fixed dental prostheses, and 41 removable dentures. Proportions of crowned teeth were significantly different between the samples; proportions of replaced teeth were not. Of the 58 incomplete dentitions analyzed, 19 were restored to the level of completeness, 15 resulted in slightly interrupted, and 24 in shortened dentitions.Conclusions. Predominantly fixed restorations were provided to restore mutilated dentitions to a functional level and not necessarily to complete dentitions.
Ambulance Crash Characteristics in the US Defined by the Popular Press: A Retrospective Analysis
Authors: Sanddal Teri L. , Sanddal Nels D. , Ward Nicolas , Stanley Laura
Published: December 2010

Ambulance crashes are a significant risk to prehospital care providers, the patients they are carrying, persons in other vehicles, and pedestrians. No uniform national transportation or medical database captures all ambulance crashes in the United States. A website captures many significant ambulance crashes by collecting reports in the popular media (the website is mentioned in the introduction). This report summaries findings from ambulance crashes for the time period of May 1, 2007 to April 30, 2009. Of the 466 crashes examined, 358 resulted in injuries to prehospital personnel, other vehicle occupants, patients being transported in the ambulance, or pedestrians. A total of 982 persons were injured as a result of ambulance crashes during the time period. Prehospital personnel were the most likely to be injured. Provider safety can and should be improved by ambulance vehicle redesign and the development of improved occupant safety restraints. Seventy-nine (79) crashes resulted in fatalities to some member of the same groups listed above. A total of 99 persons were killed in ambulance crashes during the time period. Persons in other vehicles involved in collisions with ambulances were the most likely to die as a result of crashes. In the urban environment, intersections are a particularly dangerous place for ambulances.
Modelling and Simulation for Energy Production Parametric Dependence in Greenhouses
Authors: Carlini Maurizio , Castellucci Sonia
Published: December 2010

Greenhouses crops in Italy are made by using prefabricated structures, leaving out the preliminary study of optical and thermal exchanges between the external environment and the greenhouse, dealing with heating and cooling and the effects of air conditioning needed for plant growth. This involves rather significant costs that directs the interest of designers, builders, and farmers in order to seek constructive solutions to optimize the system of such emissions. This work was done by building a model of gases using TRNSYS software, and these gases then have been checked for compliance. The model was constructed considering an example of a prefabricated greenhouse, located in central of Italy. Aspects of the structural components, and thermal and optical properties are analyzed in order to achieve a representation of reality.
Controlled Synthesis of ZnO Nanostructures by Electrodeposition Method
Authors: Jiangfeng Gong , Zhaoming Dou , Qingping Ding , Yuan Xu , Weihua Zhu
Published: December 2010

We present here a systematic study on the synthesis of various ZnO nanostructures by electrodeposition method with ZnCl2 solution as starting reactant. Several reaction parameters were examined to develop an optimal procedure for controlling the size, shape, and surface morphology of the nanostructure. The results showed that the morphology of the products can be carefully controlled through adjusting the concentration of the electrolyte. The products present well‐aligned nanorod arrays when the concentration is low. However, they act as anomalous hexangular nanoplates when the concentration of ZnCl2 is higher than 5 mM. Transmission electron microscopy and select area electron diffraction results show that the product presents good crystallinity. A possible formation process has been proposed.
Analysis of a New Dissipation System for a Solar Cooling Installation
Authors: Bailo Carlos Monné , Garcés Sergio Alonso , Arizón Fernando Palacín
Published: December 2010

This paper describes a solar absorption cooling installation located at the University of Zaragoza (Spain). The installation is based on the performance of an absorption chiller. The solar cooling system consists of 37,5 m2 of flat plate collector, a 4.5 kW, single-effect LiBr-H2O absorption chiller, and a dry cooling tower. The installation provides cooling to a gymnasium belonging to the sports center of the university. To carry out the installation analysis, the system was continuously monitored. In 2007, 2008 and 2009, several studies have been performed in order to analyze the full system operation. The measured data showed the strong influence of the cooling water temperature and the generator driving temperature on the COP. Due to the experimental evidence of the influence of the cooling water temperature, a new heat rejection system based on a geothermal heat sink has been installed and studied.