bluuebunny/crossref_metadata_2025 huggingface dataset:
PUBLIC OPINION AND THE FOUNDATION OF THE JUVENILE COURT*
Authors: MEARS DANIEL P. , HAY CARTER , GERTZ MARC , MANCINI CHRISTINA
Published: March 2007

Over 100 years ago, juvenile courts emerged out of the belief that juveniles are different from adults—less culpable and more rehabilitatable—and can be "saved" from a life of crime and disadvantage. Today, the juvenile justice system is under attack through increasing calls to eliminate it and enactment of statutes designed to place younger offenders in the adult justice system. However, little evidence exists that policy makers have taken the full range of public views into account. At the same time, scholarly accounts of calls to eliminate the juvenile justice system have neglected the role of public opinion. The current study addresses this situation by examining public views about 1) abolishing juvenile justice and 2) the proper upper age of original juvenile court jurisdiction. Particular attention is given to the notion that child‐saving and "get tough" orientations influence public views about juvenile justice. The analyses suggest support for the lingering appeal of juvenile justice among the public and the idea that youth can be “saved,” as well as arguments about the politicization and criminalization of juvenile justice. They also highlight that the public, like states, holds variable views about the appropriate age of juvenile court jurisdiction. We discuss the implications of the study and avenues for future research.

Why is it not just and proper to treat these juvenile offenders, as we deal with the neglected children, as a wise and merciful father handles his own child whose errors are not discovered by the authorities? Why is it not the duty of the state, instead of asking merely whether a boy or a girl has committed a specific offense, to find out what he is, physically, mentally, morally, and then if it learns that he is treading the path that leads to criminality, to take him in charge, not so much to punish as to reform, not to degrade but to uplift, not to crush but to develop, to make him not a criminal but a worthy citizen.
INVESTIGATING RACIAL PROFILING BY THE MIAMI‐DADE POLICE DEPARTMENT: A MULTIMETHOD APPROACH
Authors: ALPERT GEOFFREY P. , DUNHAM ROGER G. , SMITH MICHAEL R.
Published: March 2007

Research Summary

The perception and existence of biased policing or racial profiling is one of the most difficult issues facing contemporary American society. Citizens from minority communities have focused their concerns on the improper use of race by law enforcement officers. The current research uses a complex methodological approach to investigate claims that the Miami‐Dade, Florida Police Department uses race improperly for the purposes of making traffic stops and conducting post‐stop activities. The results are mixed in that the officer's aggregate actions do not show a pattern of discriminatory actions toward minority citizens when making a traffic stop, but results of post‐stop activities do show some disparate treatment of minorities.

Policy Implications

Five specific policy recommendations are made to reduce the perception or reality of racial profiling by the police. First, police departments must have clear policies and directives explaining the proper use of race in decision making. Second, officers must be trained and educated in the overall impact of using race as a factor in deciding how to respond to a citizen. Third, the department must maintain a data‐collection and analytic system to monitor the activities of their officers as it pertains to the race of the citizen. The fourth police recommendation involves the use of record checks in the field that can set in motion a process that results in the detention and arrest of citizens. Fifth, the completion of a record of interrogation for later intelligence has implications for the citizen. The use of this intelligence tool must depend on suspicion rather than on the race of the citizen.
“POLICE DON'T LIKE BLACK PEOPLE”: AFRICAN‐AMERICAN YOUNG MEN'S ACCUMULATED POLICE EXPERIENCES*
Authors: BRUNSON ROD K.
Published: March 2007

Research Summary

This study examined 40 African‐American young men's direct and vicarious experiences with police harassment and violence, and their impact on perceptions of police. Study findings highlight the value of using comprehensive and nuanced measures of police/citizen encounters and underscore the importance of examining the impact of accumulated adverse experiences.

Policy Implications

The findings have implications for police oversight policies. In particular, police organizations should work toward developing complaint review processes that are not merely accessible to citizens but also inspire confidence among them. These efforts are crucial toward improving the image of police in minority communities and positively impacting citizen trust of, and satisfaction with, the police.
THE RACE/ETHNICITY DISPARITY IN MISDEMEANOR MARIJUANA ARRESTS IN NEW YORK CITY*
Authors: GOLUB ANDREW , JOHNSON BRUCE D. , DUNLAP ELOISE
Published: March 2007

Research Summary

This article examines the growth in marijuana misdemeanor arrests in New York City (NYC) from 1980 to 2003 and its differential impact on blacks and Hispanics. Since 1980, the New York City Police Department (NYPD) expanded its use of arrest and detention for minor offenses under its quality‐of‐life (QOL) policing initiative. Arrest data indicate that during the 1990s the primary focus of QOL policing became smoking marijuana in public view (MPV). By 2000, MPV had become the most common misdemeanor arrest, accounting for 15% of all NYC adult arrests and rivaling controlled substance arrests as the primary focus of drug abuse control. Of note, most MPV arrestees have been black or Hispanic. Furthermore, black and Hispanic MPV arrestees have been more likely to be detained prior to arraignment, convicted, and sentenced to jail than their white counterparts.

Policy Implications

In light of the disparities, we recommend that the NYPD consider scaling back on MPV enforcement and reducing the harshness of treatment by routinely issuing Desk Appearance Tickets when the person is not wanted on other charges, so that most MPV arrestees would not be detained. Furthermore, we recommend that legislators should consider making smoking marijuana in public a violation and not a misdemeanor. Lastly, we suggest ways that NYC could monitor the effectiveness of these policy modifications to assure that the city continues to meet its goals for order maintenance.
Proventricular dilatation disease: an emerging exotic disease of parrots in Australia
Authors: Doneley RJT , Miller RI , Fanning TE
Published: March 2007

Proventricular dilatation disease is a viral disease seen as a segmental neuropathy in parrots. It has always been believed to be a disease exotic to Australia, with the only reported case being a legally imported Green Wing Macaw (Ara chloroptera) in 1993. This paper reports a cluster of cases seen in south‐east Queensland in 2005 to 2006. Clinical signs, autopsy findings and histopathological findings are described. No pattern or common source for these cases could be identified. The implications for Australian aviculture and avifauna are discussed.
Adoption of biosecurity practices in the Australian poultry industries
Authors: East IJ
Published: March 2007

Objective  To determine the level of adoption within the Australian poultry industries of a range of standard biosecurity practices.

Design  A questionnaire survey of owners and managers of 1753 commercial poultry farms.

Procedure  Information was collected by telephone or in person from the owners and managers of poultry farms. Data were entered onto an Excel spreadsheet and analysed using the statistical tools within Excel.

Results  The response rates to the questionnaire for the chicken meat, egg, duck and turkey sectors were 94%, 37%, 92% and 96% respectively. Within the chicken meat sector, the adoption rate exceeded 98% for 11 practices with only the rates for appropriate disposal of spent litter/manure (94%) and development of farm level biosecurity plans (88%) falling below this level. Adoption rates for all practices had increased or remained at 100% since the last survey conducted in 2001. Integrated companies in the turkey and duck sector also reported high levels of adoption for most biosecurity practices although rates for the use of fresh litter, cleaning of sheds between batches of birds and maintenance of single age flocks were lower than in the chicken meat sector. Adoption rates for biosecurity practices on independently owned farms in the turkey and duck sectors were lower than for farms operated by integrated companies.

Conclusions  Farms in the chicken meat, turkey and duck sectors of the Australian poultry industries have a high level of adoption of biosecurity practices with only a small proportion of farms needing to further enhance their biosecurity.
Welfare consequences of mulesing of sheep
Authors: Lee C , Fisher AD
Published: March 2007

Mulesing is traditionally performed on approximately 80% of Merino wool‐producing sheep in Australia. Mulesing produces a stress response that persists for 24 to 48 hours. Behavioural changes indicative of pain and discomfort resolve within 24 and 48 hours, respectively. Reductions in weight gain may persist for 14 days. The acute stress response to mulesing has been shown to be similar to that produced by shearing, castration and mild flystrike, but mulesing has a longer duration of response (24 to 48 hours) than shearing (1 hour) or knife castration (8 to 24 hours), whereas flystrike response persists for the duration of infection. Theoretically, if mulesing were not used, with Merino sheep of existing genetics, increased chemical use and flock inspections could keep flystrike rates to approximately equivalent to present levels in some production systems. Increased handling events for chemical preventative application would represent a mild stressor for sheep, but cumulatively not more than that of mulesing. If producers were able and prepared to sufficiently increase resources into alternative anti‐flystrike methods, then the welfare of Merino sheep would probably be equivalent or better to that of today. If constraints such as property size or finances dictate a sub‐optimal level of flystrike prevention and treatment, then animal welfare will unquestionably be worse. The result of that equation would depend on individual flock managers, the physical characteristics of their production system, the profitability of their business, and seasonal variations in flystrike risk. It is likely that there would be some occasions when flystrike would increase. This highlights the need for alternative strategies, such as genetic selection, to reduce the susceptibility of Australian Merino sheep to flystrike.
Prevalence and Severity of Dental Caries in Adolescents Aged 12 and 15 Living in Communities with Various Fluoride Concentrations
Authors: Pontigo‐Loyola América Patricia , Medina‐Solis Carlo Eduardo , Borges‐Yañez S. Aida , Patiño‐Marín Nuria , Islas‐Márquez Arturo , Maupome Gerardo
Published: March 2007

Objectives: To determine the experience, prevalence, and severity of dental caries in adolescents naturally exposed to various fluoride concentrations.

Methods: A cross‐sectional census was conducted on 1,538 adolescents aged 12 and 15 years living at high altitude above sea level (>2,000 m or >6,560 ft) in above‐optimal fluoridated communities (levels ranging from 1.38 to 3.07 ppm) of Hidalgo, Mexico. Sociodemographic and socioeconomic data were collected using questionnaires. Two previously trained and standardized examiners performed the dental exams.

Results: Caries prevalence was 48.6 percent and mean of decay, missing, and filling teeth (DMFT) for the whole population was 1.15 ± 1.17. In terms of severity, 9.6 percent of the adolescents had DMFT ≥ 4, and 1.7 percent had ≥7. The significant caries index (SiC) was 2.41 in the group of 12‐year‐olds, and 3.46 in the 15‐year‐olds. Higher experience and prevalence were observed in girls, in children with dental visit in the past year, those in the wealthiest socioeconomic status (SES) (quartiles 2, 3, and 4), those whose locale of residence is in San Marcos and Tula Centro, and in fluorosis‐free children and those with moderate/severe fluorosis. In an analysis of caries severity (DMFT ≥ 4), both adolescents with very mild/mild and moderate/severe dental fluorosis have higher caries severity.

Conclusions: The results indicated that caries experience, prevalence, and severity as well as SiC index among 12‐ and 15‐year‐old adolescents were relatively low. Sociodemographic and socioeconomic variables commonly associated with dental caries were also observed in Mexican adolescents. Unlike other studies, we found that caries increased with higher SES. Fluoride exposure (measured through fluorosis presence) does not appear to be reducing the caries prevalence (DMFT > 0) or caries severity (DMFT ≥ 4) in these high‐altitude communities.
Predictors of Dental Caries Development in 1.5‐Year‐Old High‐Risk Children in the Japanese Public Health Service
Authors: Sakuma Shihoko , Nakamura Muneto , Miyazaki Hideo
Published: March 2007

Objectives: The purpose of this study was to construct prediction models for 1.5‐year‐old children who were at risk for the development of caries.

Methods: The participants were 5,107 Japanese children who resided in 21 municipalities in the Shizuoka prefecture and received oral health examinations at both 1.5 and 3 years old. General practitioners in the respective municipalities conducted the examination and the evaluation of plaque deposit. At the examination at 1.5 years old, the guardians were asked to complete a questionnaire concerning the child care environment and the health habits of the children and themselves. They were divided into four groups based on the population of the concerned municipality. Approximately 30 percent of the subjects in each group were found to be in the high‐risk category (Δdft ≥ 1 during both examinations). A stepwise multivariate logistic regression analysis in each group was performed using high‐risk subjects as the dependent variable and 28 independent variables from the examination at 1.5 years old and the questionnaire.

Results: A significant model could be constructed for each group using eight to 14 independent variables, respectively. The variables common to more than three groups are related to the child’s characteristics, especially sugar consumption, feeding, and caries experiences. The predictive ability of the models had a sensitivity of 58.0 to 64.0 percent and a specificity of 64.1 to 70.5 percent. Because the negative predictive value was 77.4 to 80.5 percent, these models might be considered to be in the permissible range.

Conclusions: The models could not predict caries risk but may be able to predict those cases who will not develop caries.
Racial and Ethnic Variation in the Provision of Dental Procedures
Authors: Okunseri Christopher , Bajorunaite Ruta , Matthew Richards , Iacopino Anthony M.
Published: March 2007

Objectives: Most of the available information on racial/ethnic disparities in oral health is based on differences in sociodemographic variables related to dental disease burden, dental visits, and access to care. However, very little is known regarding racial/ethnic variation in the provision of dental procedures. This study examined trends in the provision of dental procedures and sought to determine whether there are racial/ethnic differences in the provision of dental procedures.

Methods: This is a retrospective observational study of patients treated at a dental training institution. Data for all patients 18 to 60 years of age in axiUm (electronic database) for 2001 to 2003 were analyzed. Data include demographic information, poverty status, insurance coverage, dental procedure, and race/ethnicity. Separate logistic regression models (by dental procedure category and year) were fitted while considering race/ethnicity, insurance coverage, poverty status, marital status, and age as possible covariates.

Results: The total number of dental procedures completed by providers increased by 14,000 between 2001 and 2003. African‐Americans were significantly less likely to have restorative procedures [odds ratio (OR): 0.60, 95 percent confidence interval (CI): 0.42 to 0.86], (OR: 0.52, 95 percent CI: 0.38 to 0.73), (OR: 0.46, 95 percent CI: 0.36 to 0.58) in 2001, 2002, and 2003, respectively, than the White population. Significant differences in the use of other dental procedures (prosthodontics – removable) and oral surgery procedures by race/ethnicity were observed.

Conclusions: Substantial racial/ethnic variation in the provision of dental procedures exists. This study presents findings beyond anecdotal information on racial/ethnic variation in the provision of dental procedures and requires further research to compile more detailed data.
Coping with Toothache Pain: A Qualitative Study of Low‐Income Persons and Minorities
Authors: Cohen Leonard A. , Harris Shelly L. , Bonito Arthur J. , Manski Richard J. , Macek Mark D. , Edwards Robert R. , Cornelius Llewellyn J.
Published: March 2007

Objectives: This study examined the behavioral impact of toothache pain as well as self‐care strategies for pain relief among minority and low‐income individuals.

Methods: Eight focus group sessions were conducted with 66 participants drawn from low‐income non‐Hispanic White, non‐Hispanic Black, and Hispanic adults over the age of 20 who had experienced a toothache during the previous 12‐month period and who had utilized self‐care or care from a nondentist.

Results: Toothache pain was described as intense, throbbing, miserable, or unbearable. Focus group participants indicated that toothache pain affected their ability to perform normal activities, such as their job, housework, social activities, sleeping, talking, and eating, as well as making them depressed and affecting their social interactions. Numerous prescription and nonprescription medications as well as home remedies and self‐care strategies were used for pain relief, although these were generally of limited and uncertain benefit. While receiving care at a dental office was the most preferable option for care, most participants reported multiple barriers, including the cost of dental care that resulted in long delays in seeking dental care. The main reason for eventually seeking dental care was the severity of the pain.

Conclusions: Although removing financial barriers alone may not lead to preventive dental visits, it would facilitate more timely visits to dentists to treat toothache pain.
Use of Dental Care by Elderly Chinese Immigrants in Canada
Authors: Lai Daniel W. L. , Hui Nelson T. A.
Published: March 2007

Objectives: This study examines the predictors for elderly Chinese immigrants’ use of dental care services.

Methods: In 2003, a study entitled “Health and Well Being of Older Chinese in Canada” collected data from seven cities in which 2,272 Chinese Canadians aged 55 years and older were surveyed. Data from 1,537 of these individuals were used to examine the use of dental care services by the elderly Chinese. Hierarchical logistic regression analysis was used to examine the predicting factors for use of dental care.

Results: More than half (52.1 percent) of the elder Chinese immigrants did not use any dental care services within the past year of the study. Being older, living in Quebec, and having poorer physical health reduced the probability that an older Chinese immigrant would use dental care services. On the other hand, being an immigrant from Hong Kong, having lived in Canada for a longer period of time, strong social support, and having dental problems increase the probability of dental service use.

Discussion: The findings support the need for considering the cultural characteristics and background of elderly Chinese immigrants when strengthening oral health promotion. This should encompass understanding of the holistic concept of health that includes oral health and its connections with other physical health issues.
Dental Amalgam and Multiple Sclerosis: A Systematic Review and Meta‐Analysis
Authors: Aminzadeh Kevin K. , Etminan Mahyar
Published: March 2007

Objectives: Amalgam restorations have long been controversial due to their mercury content. Allegations that the mercury may be linked to nervous disorders such as Alzheimer’s, chronic fatigue syndrome, and multiple sclerosis (MS) have fueled the calls for the removal of amalgam restorations from dentists’ armamentarium. To explore and quantify the association between amalgam restorations and MS we have conducted a systematic review and meta‐analysis of the literature.

Methods: A systematic search in Medline (from 1966 to April 2006), EMBASE (2006, Week 16), and the Cochrane library (Issue 2, 2006) for English‐language articles meeting specific definitions of MS and amalgam exposure was conducted. Studies were also identified using the references of retrieved articles. Studies were independently reviewed by two authors and disagreements were resolved by consensus. Studies were selected based on an a priori of defined criteria. Odds ratios (ORs) or relative risks were pooled using the random effects model. Heterogeneity was assessed using Q statistics.

Results: The pooled OR for the risk of MS among amalgam users was consistent, with a slight, nonstatistically significant increase between amalgam use and risk of MS.

Conclusion: Future studies that take into consideration the amalgam restoration size and surface area along with the duration of exposure are needed in order to definitively rule out any link between amalgam and MS.
The use of recombinant activated factor VII in life‐threatening postpartum hemorrhage
Authors: FRANCHINI MASSIMO
Published: March 2007

Bleeding is still a major cause of morbidity and mortality in obstetrics. As recent reports have documented the successful treatment of some cases of postpartum hemorrhage (PPH) refractory to standard treatment with recombinant activated factor VII (rFVIIa), we have performed a systematic review of the existing literature on this topic. Although supported by few and uncontrolled studies, on the whole the published data suggest a potential role of rFVIIa in the management of severe PPH. However, further evidences are needed in order to better assess the optimal dose, the effectiveness and the safety of rFVIIa in such critical bleeding condition.
Tolerability and efficacy of parenteral iron therapy in hemodialysis patients, a comparison of preparations
Authors: MONIEM KHALID A. , BHANDARI SUNIL
Published: March 2007

Hemodialysis patients require parenteral iron to replenish/maintain sufficient iron stores and optimize erythropoietin (EPO) use. Two parenteral iron preparations are available in the UK, iron dextran (CosmoFer) and iron sucrose (Venofer). Debate about their safety profiles continues.

We performed an observational study of chronic kidney disease patients and a prospective crossover study in hemodialysis patients to examine the comparative safety and tolerability of CosmoFer and Venofer. Side effects, hemoglobin, ferritin and EPO dose were recorded.

One hundred and forty‐four patients received CosmoFer (2294 doses) and 110 received Venofer (2111 doses). Fifteen reactions occurred with no anaphylactic episodes in either group. Thirty‐nine patients (28 men), mean age 60.5 years, on intravenous Venofer were converted to CosmoFer for 6 months. They were then converted back to Venofer. No differences in hemoglobin, EPO dose or ferritin levels throughout the study were observed. Side effects were minor after 546 and 507 doses of CosmoFer and Venofer (13 reactions (eight CosmoFer, five Venofer) occurred in eight patients). Conversion from Venofer to CosmoFer led to a cost saving of £77 per patient over the 6‐month study period.

In this study, the two forms of therapy were equally safe and effective. Examination of a larger cohort of patients is necessary to verify these findings and potentially reassess European Best Practice Guidelines.
Mechanism Dynamics Sequence-Solution Method and Its Application
Authors: Yun Zhao , Gao-Hong Yu , Jian-Neng Chen , Ge Li
Published: March 2007

In order to eliminate the interference of reverse-driving and the positive or negative value of normal pressure on the direction of frictional force, in solving mechanism dynamics equations, a dynamics sequence solution (DSS) is proposed. For this purpose a moment equation about joints for links is proposed, and it, together with the traditional mechanics equation of links, forms a dynamic-equation set, to provide a basic equation set of mechanism dynamics. In order to explain DSS, the force at a particular joint is considered in terms of the normal and tangential directions, and the resolution of the problem using a four-bar linkage mechanism as an example, are explained. The solution procedures diagrams for different driving types of reverse-driving force, as well as the solution process for friction force under normal pressure, are described. With a dry-straw-compression mechanism as the example, a dynamic model of the mechanism is established, and the above proposed DSS is used to find unknown forces. Finally, the dynamic characteristics of rotary-transplanting mechanisms (the key component of high-speed rice transplanter) are analyzed, through the proposed DSS, and the results are verified in a test-bed situation. The consistency of the test results with the theoretical ones shows that the proposed DSS is able to effectively solve the dynamics equations of complicated mechanisms. In this part, the authors introduced DSS and discussed the feasibility of its application.
A Modified Lindstedt–Poincaré Method for Strongly Mixed-Parity Nonlinear Oscillators
Authors: Sun W. P. , Wu B. S. , Lim C. W.
Published: March 2007

By introducing linear and constant terms with an undetermined parameter and subsequently using certain rules to determine the optimal value of the parameter, we establish analytical approximate frequencies and the corresponding periodic solutions for strongly mixed-parity nonlinear oscillators. A quadratic–cubic nonlinear oscillator is used to verify and illustrate the usefulness and effectiveness of the proposed method.
An Improved Tool Path Model Including Periodic Delay for Chatter Prediction in Milling
Authors: Faassen R. P. H. , van de Wouw N. , Nijmeijer H. , Oosterling J. A. J.
Published: March 2007

The efficiency of the high-speed milling process is often limited by the occurrence of chatter. In order to predict the occurrence of chatter, accurate models are necessary. In most models regarding milling, the cutter is assumed to follow a circular tooth path. However, the real tool path is trochoidal in the ideal case, i.e., without vibrations of the tool. Therefore, models using a circular tool path lead to errors, especially when the cutting angle is close to 0 or π radians. An updated model for the milling process is presented which features a model of the undeformed chip thickness and a time-periodic delay. In combination with this tool path model, a nonlinear cutting force model is used, to include the dependency of the chatter boundary on the feed rate. The stability of the milling system, and hence the occurrence of chatter, is investigated using both the traditional and the trochoidal model by means of the semi-discretization method. Due to the combination of this updated tool path model with a nonlinear cutting force model, the periodic solution of this system, representing a chatter-free process, needs to be computed before the stability can be investigated. This periodic solution is computed using a finite difference method for delay-differential equations. Especially for low immersion cuts, the stability lobes diagram (SLD) using the updated model shows significant differences compared to the SLD using the traditional model. Also the use of the nonlinear cutting force model results in significant differences in the SLD compared to the linear cutting force model.
Round an expanding world: A simple model to illustrate the kinematical effects of the cosmological expansion
Authors: Criado C. , Alamo N.
Published: March 2007

We use a rubber balloon model to give a simple explanation of the motion of photons and galaxies in an expanding and collapsing universe. In particular, we study the Friedmann-Lemaitre-Robertson-Walker closed universe. The behavior of the peculiar velocity of galaxies in an expanding universe is also studied with the help of this model.
Superlinearly convergent homogeneous maps and period of the pendulum
Authors: Siboni S.
Published: March 2007

The period of a pendulum can be accurately determined by an arithmetic-geometric map. The high efficiency of the map is due to superlinear convergence, which can be understood from a geometrical point of view by writing the map as a skew system (or master-slave system) whose master component has a globally asymptotically stable fixed point with order of convergence two, which reduces the behavior of the map to a one-dimensional dynamics. It is shown that the map shares many features with a general class of maps of the real plane.
Giving bonus points based on oral exams
Authors: Ehrlich Robert
Published: March 2007

A pedagogical experiment of giving bonus points based on oral exams in an introductory physics course is described. The orals covered the questions on a written exam that had just been graded and returned to the class. Although the performance of most students on the oral exams was fair at best, the value of bonus point orals would appear to be considerable, even though it may not be applicable to large classes and have other important disadvantages.
The first-order orbital equation
Authors: D’Eliseo Maurizio M.
Published: March 2007

We derive the first-order orbital equation employing a complex variable formalism. We then examine Newton’s theorem on precessing orbits and apply it to the perihelion shift of an elliptic orbit in general relativity. It is found that corrections to the inverse-square gravitational force law formally similar to that required by general relativity were suggested by Clairaut in the 18th century.
Why the near field radiation from a large distributed source is independent of position
Authors: Doty Duane R. , Scudder Henry J. , Gupta Ravi R. , Saa Carlos Y.
Published: March 2007

Background radiation from terrestrial sources of uranium, thorium, and potassium complicate the counting of radiation from a weak source. Although radiation from a localized point source decreases as the inverse square of the distance from the source, moving a counter further from a concrete table or floor does not decrease the background. Measurements of the intensity of radiation versus height above a local surface were made and found not to vary with height. A simple model is proposed assuming a uniform volume distribution with self-absorption as a source. It is shown that most of the radiation comes from relatively close surroundings.
Ghost imaging: Open secrets and puzzles for undergraduates
Authors: Basano Lorenzo , Ottonello Pasquale
Published: March 2007

Ghost imaging, a novel technique in which the object and the image system are on separate optical paths, was first demonstrated using entangled photon pairs. This demonstration caused it to be regarded as a purely quantum effect, but subsequent work gave wide support to a classical explanation. We provide an introduction to ghost imaging based more on intuition than on formalism and discuss several experiments that can be implemented in a university physics laboratory.
Susceptibility of Drug-Resistant Clinical Herpes Simplex Virus Type 1 Strains to Essential Oils of Ginger, Thyme, Hyssop, and Sandalwood
Authors: Schnitzler Paul , Koch Christine , Reichling Jürgen
Published: March 2007

Acyclovir-resistant clinical isolates of herpes simplex virus type 1 (HSV-1) were analyzed in vitro for their susceptibilities to essential oils of ginger, thyme, hyssop, and sandalwood. All essential oils exhibited high levels of virucidal activity against acyclovir-sensitive strain KOS and acyclovir-resistant HSV-1 clinical isolates and reduced plaque formation significantly.
Exposure-Response Analyses of Tigecycline Efficacy in Patients with Complicated Skin and Skin-Structure Infections
Authors: Meagher A. K. , Passarell J. A. , Cirincione B. B. , Van Wart S. A. , Liolios K. , Babinchak T. , Ellis-Grosse E. J. , Ambrose P. G.
Published: March 2007

Exposure-response analyses were performed for the microbiological and clinical efficacy of tigecycline in the treatment of complicated skin and skin-structure infections, where
Staphylococcus aureus
and streptococci are the predominant pathogens. A prospective method was developed to create homogeneous patient populations for PK-PD analyses. Evaluable patients from three clinical trials were pooled for analysis. Patients received a tigecycline 100-mg loading dose/50 mg every 12 h or a 50-mg loading dose/25 mg every 12 h. At the test-of-cure visit, microbiologic and clinical responses were evaluated. Patients were prospectively evaluated and classified into cohorts based on baseline pathogens:
S. aureus
only (cohort 1), monomicrobial
S. aureus
or streptococci (cohort 2), two gram-positive pathogens (cohort 3), polymicrobial (cohort 4), or other monomicrobial infections (cohort 5). A prospective procedure for combining cohorts was used to increase the sample size. Logistic regression evaluated steady-state 24-h area under the concentration-time curve (AUC
24
)/MIC ratio as a predictor of response, and classification and regression tree (CART) analyses were utilized to determine AUC/MIC breakpoints. Analysis began with pooled cohorts 2 and 3, the focus of these analyses, and included 35 patients with 40
S. aureus
and/or streptococcal pathogens. CART analyses identified a significant AUC/MIC breakpoint of 17.9 (
P
= 0.0001 for microbiological response and
P
= 0.0376 for clinical response). The continuous AUC/MIC ratio was predictive of microbiological response based on sample size (
P
= 0.0563). Analysis of all pathogens combined decreased the ability to detect exposure-response relationships. The prospective approach of creating homogeneous populations based on
S. aureus
and streptococci pathogens was critical for identifying exposure-response relationships.
Preclinical Testing of Candidate Topical Microbicides for Anti-Human Immunodeficiency Virus Type 1 Activity and Tissue Toxicity in a Human Cervical Explant Culture
Authors: Cummins James E. , Guarner Jeannette , Flowers Lisa , Guenthner Patricia C. , Bartlett Jeanine , Morken Timothy , Grohskopf Lisa A. , Paxton Lynn , Dezzutti Charlene S.
Published: March 2007

A human cervical explant culture was utilized for the preclinical assessment of anti-human immunodeficiency virus type 1 (HIV-1) activity and tissue toxicity of formulated, candidate topical microbicides. Products tested included cellulose acetate 1,2-benzene dicarboxylate (CAP), a carrageenan-based product (PC-515), a naphthalene sulfonate polymer (PRO 2000), a lysine dendrimer (SPL7013), a nonnucleoside reverse transcriptase inhibitor (UC781), and an antimicrobial peptide (D2A21), along with their placebos. Cervical explants were cultured overnight with HIV-1 with or without product, washed, and monitored for signs of HIV-1 infection. HIV-1 infection was determined by p24gag levels in the basolateral medium and by immunohistochemical analysis of the explant. Product toxicity was measured by the MTT [1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan] assay and histology. CAP, PRO 2000, SPL7013, and UC781 consistently prevented HIV-1 infection in all explants tested. PC-515 and D2A21 prevented HIV-1 infection in 50% or fewer of the explants tested. Placebos did not prevent infection in any of the explants tested. With the exception of PRO 2000 (4%), the MTT assay and histological analysis of the other products and placebos showed minimal toxicity to the epithelium and submucosa. Collectively, these data suggest that this culture system can be used for evaluating the safety and efficacy of topical microbicides designed for vaginal use.
Defining the Molecular Forces That Determine the Impact of Neomycin on Bacterial Protein Synthesis: Importance of the 2′-Amino Functionality
Authors: Barbieri Christopher M. , Kaul Malvika , Bozza-Hingos Melanie , Zhao Fang , Tor Yitzhak , Hermann Thomas , Pilch Daniel S.
Published: March 2007

2-Deoxystreptamine (2-DOS) aminoglycosides exert their antibiotic actions by binding to the A site of the 16S rRNA and interfering with bacterial protein synthesis. However, the molecular forces that govern the antitranslational activities of aminoglycosides are poorly understood. Here, we describe studies aimed at elucidating these molecular forces. In this connection, we compare the bactericidal, antitranslational, and rRNA binding properties of the 4,5-disubstituted 2-DOS aminoglycoside neomycin (Neo) and a conformationally restricted analog of Neo (CR-Neo) in which the 2′-nitrogen atom is covalently conjugated to the 5′′-carbon atom. The bactericidal potency of Neo exceeds that of CR-Neo, with this enhanced antibacterial activity reflecting a correspondingly enhanced antitranslational potency. Time-resolved fluorescence anisotropy studies suggest that the enhanced antitranslational potency of Neo relative to that of CR-Neo is due to a greater extent of drug-induced reduction in the mobilities of the nucleotides at positions 1492 and 1493 of the rRNA A site. Buffer- and salt-dependent binding studies, coupled with high-resolution structural information, point to electrostatic contacts between the 2′-amino functionality of Neo and the host rRNA as being an important modulator of 1492 and 1493 base mobilities and therefore antitranslational activities.
Effect of Macrolide Usage on Emergence of Erythromycin-Resistant
Campylobacter
Isolates in Chickens
Authors: Lin Jun , Yan Meiguan , Sahin Orhan , Pereira Sonia , Chang Yun-Juan , Zhang Qijing
Published: March 2007

In this work we conducted both in vitro and in vivo experiments to examine the development and mechanisms of erythromycin (Ery) resistance in
Campylobacter jejuni
and
Campylobacter coli
. In vitro plating revealed that both
Campylobacter
species had similar but low spontaneous mutation frequencies (3 × 10
−9
to <5.41 × 10
−10
) for Ery resistance. Chickens infected with
C. jejuni
or
C. coli
were subjected to single or multiple treatments with medicated water containing tylosin (0.53 g/liter), which transiently reduced the level of
Campylobacter
colonization but did not select for Ery-resistant (Ery
r
) mutants in the treated birds. However, when tylosin was given to the chickens in feed at a growth-promoting dose (0.05 g/kg feed), Ery
r
mutants emerged in the birds after prolonged exposure to the antibiotic. The vast majority of the in vitro- and in vivo-selected
Campylobacter
mutants with Ery MICs of 8 to 256 μg/ml lacked the known resistance-associated mutations in the 23S rRNA gene, while the highly resistant mutants (Ery MIC > 512 μg/ml) had the A2074G mutation in the 23S rRNA gene. Inactivation of CmeABC, a multidrug efflux pump, dramatically reduced the Ery MIC in all of the examined mutants regardless of the presence of the A2074G mutation. Together, these results reveal distinct features associated with Ery resistance development in
Campylobacter
, demonstrate the significant role of CmeABC in Ery resistance, and suggest that long-term use of a macrolide as a growth promoter selects for the emergence of Ery
r
Campylobacter
in animal reservoirs.
In Vitro Bactericidal Activity of the Antiprotozoal Drug Miltefosine against
Streptococcus pneumoniae
and Other Pathogenic Streptococci
Authors: Llull Daniel , Rivas Luis , García Ernesto
Published: March 2007

Miltefosine (hexadecylphosphocholine), the first oral drug against visceral leishmaniasis, triggered pneumococcal autolysis at concentrations higher than 2.5 μM. Bactericidal activity was also observed in cultures of other streptococci, although these failed to undergo lysis. The autolysis elicited by miltefosine can be attributed to triggering of the pneumococcal autolysin LytA.
Roxithromycin Favorably Modifies the Initial Phase of Resistance against Infection with Macrolide-Resistant
Streptococcus pneumoniae
in a Murine Pneumonia Model
Authors: Yasuda Yasuki , Kasahara Kei , Mizuno Fumiko , Nishi Kazuyuki , Mikasa Keiichi , Kita Eiji
Published: March 2007

Sub-MIC levels of macrolides down-regulate bacterial virulence factors and suppress inflammatory processes. The ability of macrolides to reduce the production of pneumolysin has been shown to explain the discrepancy between in vitro resistance and outcomes with macrolides against macrolide-resistant
Streptococcus pneumoniae
. In this study, we determined whether the ability of macrolides to regulate inflammatory processes is beneficial for innate resistance to macrolide-resistant pneumococci in a murine pneumonia model. Among the macrolides tested, only roxithromycin did not affect in vitro pneumococcal virulence factors at sub-MIC levels. Roxithromycin (1.25 to 10 mg/kg of body weight/day) was administered to mice by oral gavage for 3 days before infection with a resistant strain of
S. pneumoniae
. We evaluated the efficacy of the treatment by determining mouse survival curves and by measuring bacterial burdens and several inflammatory parameters in the airways. Pneumolysin and PspA in infected lungs were examined by Western blot assay. Roxithromycin at doses of ≥5 mg/kg/day increased the median survival time and retarded bacteremia without suppressing the production of pneumolysin and PspA in infected lungs. This treatment reduced matrix metalloproteinase-7 expression and activation and keratinocyte-derived chemokine production in the lungs, while it increased mononuclear cell responses in the lungs, with enhanced bacterial clearance. Concentrations of roxithromycin in plasma and tissues were below the MICs for the inoculated strain during infection. The treatment also reduced inflammatory responses to killed pneumococci in the lungs. These results suggest that the modification by roxithromycin of airway inflammatory responses, including those of matrix metalloproteinase-7 and phagocytes, is beneficial for initial resistance to macrolide-resistant pneumococci.
In Vitro Activities of Isepamicin, Other Aminoglycosides, and Capreomycin against Clinical Isolates of Rapidly Growing Mycobacteria in Taiwan
Authors: Shen Gwan-Han , Wu Bo-Da , Wu Kun-Ming , Chen Jiann-Hwa
Published: March 2007

The in vitro activities of isepamicin against 117
Mycobacteria abscessus
, 48
Mycobacterium fortuitum
, and 20
Mycobacterium chelonae
isolates were evaluated by a microdilution test. Isepamicin MIC
90
s were ≤16 μg/ml for the three species. Isepamicin was as active as amikacin and kanamycin and more active than tobramycin, capreomycin, gentamicin, and streptomycin.
The Salmochelin Siderophore Receptor IroN Contributes to Invasion of Urothelial Cells by Extraintestinal Pathogenic
Escherichia coli
In Vitro
Authors: Feldmann Friederike , Sorsa Liisa Johanna , Hildinger Kirsten , Schubert Sören
Published: March 2007

Extraintestinal pathogenic
Escherichia coli
(ExPEC) strains possess several siderophore-dependent iron uptake systems. In this study we demonstrated that the salmochelin siderophore receptor IroN is involved in the invasion of urothelial cells by ExPEC in vitro. Thus, IroN may play a dual role in the establishment of urinary tract infections, displaying an iron uptake receptor as well as an internalization factor.
Host Cell Responses to
Chlamydia pneumoniae
in Gamma Interferon-Induced Persistence Overlap Those of Productive Infection and Are Linked to Genes Involved in Apoptosis, Cell Cycle, and Metabolism
Authors: Eickhoff Meike , Thalmann Jessica , Hess Simone , Martin Myriam , Laue Thomas , Kruppa Joachim , Brandes Gudrun , Klos Andreas
Published: March 2007

The respiratory pathogen
Chlamydia
(
Chlamydophila
)
pneumoniae
is associated with chronic diseases, including atherosclerosis and giant-cell arteritis, which are accompanied by the occurrence of these obligate intracellular bacteria in blood vessels. There,
C. pneumoniae
seems to be present in a persistent state. Persistence is characterized by modified bacterial metabolism and morphology, as well as a reversible arrest of chlamydial development. In cell culture, this persistent state can be induced by gamma interferon (IFN-γ). To elucidate this long-term interaction between chlamydiae and their host cells, microarray screening on epithelial HeLa cells was performed. Transcription of persistently (and productively) infected cells was compared with that of mock-infected cells. Sixty-six host cell genes were regulated at 24 h and/or 96 h of IFN-γ-induced persistence. Subsequently, a set of 17 human host cell genes related to apoptosis, cell cycle, or metabolism was identified as permanently up- or down-regulated by real-time PCR. Some of these chlamydia-dependent host cell responses were diminished or even absent in the presence of rifampin. However, other expression patterns were not altered by the inhibition of bacterial RNA polymerase, suggesting two different modes of host cell activation. Thus, in the IFN-γ model, the persisting bacteria cause long-lasting changes in the expression of genes coding for functionally important proteins. They might be potential drug targets for the treatment of persistent
C. pneumoniae
infections.
Relaxed Cleavage Specificity of an Immunoglobulin A1 Protease from
Neisseria meningitidis
Authors: Vitovski Srdjan , Sayers Jon R.
Published: March 2007

Respiratory pathogens, such as
Neisseria meningitidis
, secrete site-specific proteases able to cleave human immunoglobulin A1 (IgA1), the first line of defense at mucosal membranes. Bacterial isolates show wide variability in IgA1 protease activity, and those isolated from patients with clinical infection possess the highest levels of activity. A feature of this enzyme is the self-cleavage required for secretion of the mature extracellular form. Known cleavage targets contain a proline-rich consensus recognition sequence, Pro-Pro-Ser-Pro, residing in the variable linker region that connects the protease and translocator domains. Here, we report the sequence of the NMB IgA1 protease and the unexpected self-cleavage and subsequent extracellular release of mature IgA1 protease from mutants lacking the previously defined consensus cleavage site. We investigated the possible link between enzyme secretion and variability in the linker sequence segment using site-directed mutagenesis and linker domain swapping to construct mutated and chimeric forms of the IgA1 protease from
N. meningitidis
strain NMB. The observed change in secreted activity levels compared to the wild-type clone indicated that the precise amino acid sequence of the intervening region, between mature IgA1 protease and the β-core translocator domain, influences the efficacy of autoproteolytic processing. The broader specificity uncovered for the NMB IgA1 protease suggests that it could cleave a far wider range of human proteins than previously appreciated.