bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of rubber particles and rubber chain elongation in Taraxacum koksaghyz
Authors: Schmidt Thomas , Lenders Malte , Hillebrand Andrea , van Deenen Nicole , Munt Oliver , Reichelt Rudolf , Eisenreich Wolfgang , Fischer Rainer , Prüfer Dirk , Gronover Christian Schulze 
Published: February 2010

Abstract

Background
Natural rubber is a biopolymer with exceptional qualities that cannot be completely replaced using synthetic alternatives. Although several key enzymes in the rubber biosynthetic pathway have been isolated, mainly from plants such as Hevea brasiliensis, Ficus spec. and the desert shrub Parthenium argentatum, there have been no in planta functional studies, e.g. by RNA interference, due to the absence of efficient and reproducible protocols for genetic engineering. In contrast, the Russian dandelion Taraxacum koksaghyz, which has long been considered as a potential alternative source of low-cost natural rubber, has a rapid life cycle and can be genetically transformed using a simple and reliable procedure. However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz.

Results
We established a method for the purification of rubber particles - the active sites of rubber biosynthesis - from T. koksaghyz latex. Photon correlation spectroscopy and transmission electron microscopy revealed an average particle size of 320 nm, and 13C nuclear magnetic resonance (NMR) spectroscopy confirmed that isolated rubber particles contain poly(cis-1,4-isoprene) with a purity >95%. Size exclusion chromatography indicated that the weight average molecular mass ("Equation missing"w) of T. koksaghyz natural rubber is 4,000-5,000 kDa. Rubber particles showed rubber transferase activity of 0.2 pmol min-1 mg-1. Ex vivo rubber biosynthesis experiments resulted in a skewed unimodal distribution of [1-14C]isopentenyl pyrophosphate (IPP) incorporation at a "Equation missing"w of 2,500 kDa. Characterization of recently isolated cis-prenyltransferases (CPTs) from T. koksaghyz revealed that these enzymes are associated with rubber particles and are able to produce long-chain polyprenols in yeast.

Conclusions

T. koksaghyz rubber particles are similar to those described for H. brasiliensis. They contain very pure, high molecular mass poly(cis-1,4-isoprene) and the chain elongation process can be studied ex vivo. Because of their localization on rubber particles and their activity in yeast, we propose that the recently described T. koksaghyz CPTs are the major rubber chain elongating enzymes in this species. T. koksaghyz is amenable to genetic analysis and modification, and therefore could be used as a model species for the investigation and comparison of rubber biosynthesis.
SING: Subgraph search In Non-homogeneous Graphs
Authors: Di Natale Raffaele , Ferro Alfredo , Giugno Rosalba , Mongiovì Misael , Pulvirenti Alfredo , Shasha Dennis 
Published: February 2010

Abstract

Background
Finding the subgraphs of a graph database that are isomorphic to a given query graph has practical applications in several fields, from cheminformatics to image understanding. Since subgraph isomorphism is a computationally hard problem, indexing techniques have been intensively exploited to speed up the process. Such systems filter out those graphs which cannot contain the query, and apply a subgraph isomorphism algorithm to each residual candidate graph. The applicability of such systems is limited to databases of small graphs, because their filtering power degrades on large graphs.

Results
In this paper, SING (Subgraph search In Non-homogeneous Graphs), a novel indexing system able to cope with large graphs, is presented. The method uses the notion of feature, which can be a small subgraph, subtree or path. Each graph in the database is annotated with the set of all its features. The key point is to make use of feature locality information. This idea is used to both improve the filtering performance and speed up the subgraph isomorphism task.

Conclusions
Extensive tests on chemical compounds, biological networks and synthetic graphs show that the proposed system outperforms the most popular systems in query time over databases of medium and large graphs. Other specific tests show that the proposed system is effective for single large graphs.
Longitudinal modelling of academic buoyancy and motivation: Do the 5Cs hold up over time?
Authors: Martin Andrew J. , Colmar Susan H. , Davey Louise A. , Marsh Herbert W. 
Published: February 2010

BackgroundAcademic buoyancy is students' ability to successfully deal with setbacks and challenges that are typical of academic life. The present study extends previous preliminary cross‐sectional work that tentatively identified five motivational predictors of academic buoyancy – referred to as the ‘5Cs’ of academic buoyancy: confidence (self‐efficacy), coordination (planning), commitment (persistence), composure (low anxiety), and control (low uncertain control).AimsThe study seeks to more clearly ascertain the effects of motivation (and its mediating role) on academic buoyancy over and above prior academic buoyancy.SampleThe study comprised N = 1,866 high school students from six schools.MethodLongitudinal data were collected (1 year apart) and the hypothesized model exploring longitudinal effects was tested using structural equation modelling.ResultsAfter controlling for prior variance in academic buoyancy, the 5Cs were significant predictors of subsequent academic buoyancy. Furthermore, over and above the direct effects of prior academic buoyancy on subsequent academic buoyancy, the 5Cs significantly mediated this relationship.ConclusionsThe study concludes with a discussion of the substantive, applied, and methodological implications for researchers and practitioners seeking to investigate and address the academic buoyancy of students who require the capacity to effectively function in an ever‐challenging school environment.
Molecular and Cellular Mechanisms Elucidating Neurocognitive Basis of Functional Impairments Associated With Intellectual Disability in Down Syndrome
Authors: Rachidi Mohammed , Lopes Carmela 
Published: February 2010

AbstractDown syndrome, the most common genetic cause of intellectual disability, is associated with brain disorders due to chromosome 21 gene overdosage. Molecular and cellular mechanisms involved in the neuromorphological alterations and cognitive impairments are reported herein in a global model. Recent advances in Down syndrome research have lead to the identification of altered molecular pathways involved in intellectual disability, such as Calcineurin/NFATs pathways, that are of crucial importance in understanding the molecular basis of intellectual disability pathogenesis in this syndrome. Potential treatments in mouse models of Down syndrome, including antagonists of NMDA or GABAA receptors, and microRNAs provide new avenues to develop treatments of intellectual disability. Nevertheless, understanding the links between molecular pathways and treatment strategies in human beings requires further research.
Correlation Between Methylphenidate and Ritalinic Acid Concentrations in Oral Fluid and Plasma
Authors: Marchei Emilia , Farré Magí , Pardo Ricardo , Garcia-Algar Oscar , Pellegrini Manuela , Pacifici Roberta , Pichini Simona 
Published: February 2010

AbstractBackground: We studied the excretion profile of methylphenidate (MPH) and its metabolite ritalinic acid (RA) in oral fluid and plasma, the oral fluid-to-plasma (OF/P) drug ratio, and the variations of oral fluid pH after drug administration.Methods: We analyzed oral fluid and plasma samples, obtained from 8 healthy volunteers after ingestion of a single dose of 20 mg fast-release or extended-release MPH, for MPH and RA by LC-MS. We estimated the apparent pharmacokinetic parameters of MPH in plasma and oral fluid and calculated the OF/P ratio for each time interval.Results: MPH and RA were detected in oral fluid. Whereas parent drug concentrations in oral fluid were an order of magnitude higher than those in plasma, the opposite was observed for RA. Oral fluid concentrations of MPH ranged between 0.5 and 466.7 μg/L and peaked at 0.5 h after administration of the fast-release formulation; they ranged between 0.7 and 89.5 μg/L and peaked at 2 h after administration of the extended-release formulation. Both formulations presented bimodal time-course curves for the OF/P ratio, ranging between 1.8 and 242.1 for the fast-release formulation and between 2.6 and 27.0 for extended-release. Oral fluid pH did not appear to be modified by the administration of the drug, and its influence on OF/P ratio did not affect the correlation of MPH between the 2 body fluids.Conclusions: The results obtained support the measurement of MPH in oral fluid as an alternative to plasma if the extended-release formulation is used.
Identification of Pathogens by Mass Spectrometry
Authors: Ho Yen-Peng , Reddy P Muralidhar 
Published: February 2010

Abstract
Background: Mass spectrometry (MS) is a suitable technology for microorganism identification and characterization.
Content: This review summarizes the MS-based methods currently used for the analyses of pathogens. Direct analysis of whole pathogenic microbial cells using MS without sample fractionation reveals specific biomarkers for taxonomy and provides rapid and high-throughput capabilities. MS coupled with various chromatography- and affinity-based techniques simplifies the complexity of the signals of the microbial biomarkers and provides more accurate results. Affinity-based methods, including those employing nanotechnology, can be used to concentrate traces of target microorganisms from sample solutions and, thereby, improve detection limits. Approaches combining amplification of nucleic acid targets from pathogens with MS-based detection are alternatives to biomarker analyses. Many data analysis methods, including multivariate analysis and bioinformatics approaches, have been developed for microbial identification. The review concludes with some current clinical applications of MS in the identification and typing of infectious microorganisms, as well as some perspectives.
Summary: Advances in instrumentation (separation and mass analysis), ionization techniques, and biological methodologies will all enhance the capabilities of MS for the analysis of pathogens.
When Intraclass Correlation Coefficients Go Awry: A Case Study From a School-Based Smoking Prevention Study in South Africa
Authors: Resnicow Ken , Zhang Nanhua , Vaughan Roger D. , Reddy Sasiragha Priscilla , James Shamagonam , Murray David M. 
Published: February 2010

Objectives. We conducted a group randomized trial of 2 South African school-based smoking prevention programs and examined possible sources and implications of why our actual intraclass correlation coefficients (ICCs) were significantly higher than the ICC of 0.02 used to compute initial sample size requirements. Methods. Thirty-six South African high schools were randomly assigned to 1 of 3 experimental groups. On 3 occasions, students completed questionnaires on tobacco and drug use attitudes and behaviors. We used mixed-effects models to partition individual and school-level variance components, with and without covariate adjustment. Results. For 30-day smoking, unadjusted ICCs ranged from 0.12 to 0.17 across the 3 time points. For lifetime smoking, ICCs ranged from 0.18 to 0.22; for other drug use variables, 0.02 to 0.10; and for psychosocial variables, 0.09 to 0.23. Covariate adjustment substantially reduced most ICCs. Conclusions. The unadjusted ICCs we observed for smoking behaviors were considerably higher than those previously reported. This effectively reduced our sample size by a factor of 17. Future studies that anticipate significant cluster-level racial homogeneity may consider using higher-value ICCs in sample-size calculations to ensure adequate statistical power.
Tuberculosis Transmission and Use of Methamphetamines in Snohomish County, WA, 1991–2006
Authors: Pevzner Eric S. , Robison Susan , Donovan Jenny , Allis Donna , Spitters Chris , Friedman Rachel , Ijaz Kashef , Oeltmann John E. 
Published: February 2010

Objectives. We investigated a cluster of tuberculosis (TB) cases among persons using methamphetamines in Snohomish County, Washington, to determine the extent of the outbreak, examine whether methamphetamine use contributed to TB transmission, and implement strategies to prevent further infections. Methods. We screened contacts to find and treat persons with TB disease or infection. We then formed a multidisciplinary team to engage substance abuse services partners and implement outreach strategies including novel methods for finding contacts and a system of incentives and enablers to promote finding, screening, and treating patients with TB and their infected contacts. Results. We diagnosed and completed treatment with 10 persons with TB disease. Eight of 9 adult patients and 67% of their adult contacts reported using methamphetamines. Of the 372 contacts, 319 (85.8%) were screened, 80 (25.1%) were infected, 71 (88.8%) started treatment for latent infection, and 57 (80.3%) completed treatment for latent infection. Conclusions. Collaborative approaches integrating TB control, outreach, incentives, and enablers resulted in high rates of treatment adherence and completion among patients and infected contacts. TB control programs should collaborate with substance abuse programs to address addiction, overcome substance abuse–related barriers to treatment, treat TB, and prevent ongoing transmission.
A Framework for Public Health Action: The Health Impact Pyramid
Authors: Frieden Thomas R. 
Published: February 2010

A 5-tier pyramid best describes the impact of different types of public health interventions and provides a framework to improve health. At the base of this pyramid, indicating interventions with the greatest potential impact, are efforts to address socioeconomic determinants of health. In ascending order are interventions that change the context to make individuals' default decisions healthy, clinical interventions that require limited contact but confer long-term protection, ongoing direct clinical care, and health education and counseling. Interventions focusing on lower levels of the pyramid tend to be more effective because they reach broader segments of society and require less individual effort. Implementing interventions at each of the levels can achieve the maximum possible sustained public health benefit.
Stereotactic radiosurgery for symptomatic solitary cerebral cavernous malformations considered high risk for resection
Authors: Lunsford L. Dade , Khan Aftab A. , Niranjan Ajay , Kano Hideyuki , Flickinger John C. , Kondziolka Douglas 
Published: February 2010

Object
A retrospective study was conducted to reassess the benefit and safety of stereotactic radiosurgery (SRS) in patients with solitary cerebral cavernous malformations (CCMs) that bleed repeatedly and are poor candidates for surgical removal.

Methods
Between 1988 and 2005 at the University of Pittsburgh, the authors performed SRS in 103 evaluable patients (57 males and 46 females) with solitary symptomatic CCMs. The mean patient age was 39.3 years. Ninety-eight percent of these patients had experienced 2 or more hemorrhages associated with new neurological deficits. Seventeen patients (16.5%) had undergone attempted resection before radiosurgery. Ninety-three CCMs were located in deep brain structures and 10 were in subcortical lobar areas of functional brain importance. The median malformation volume was 1.31 ml, and the median tumor margin dose was 16 Gy.

Results
The follow-up ranged from 2 to 20 years. The annual hemorrhage rate—that is, a new neurological deficit associated with imaging evidence of a new hemorrhage—before SRS was 32.5%. After SRS 22 hemorrhages were observed within 2 years (10.8% annual hemorrhage rate) and 4 hemorrhages were observed after 2 years (1.06% annual hemorrhage rate). The risk of hemorrhage from a CCM was significantly reduced after radiosurgery (p < 0.0001). Overall, new neurological deficits due to adverse radiation effects following SRS developed in 14 patients (13.5%), with most occurring early in our experience. Modifications in technique (treatment volume within the T2-weighted MR imaging–defined margin, use of MR imaging, and dose reduction for CCM in critical brainstem locations) further reduced risks after SRS.

Conclusions
Data in this study provide further evidence that SRS is a relatively safe procedure that reduces the rebleeding rate for CCMs located in high-surgical-risk areas of the brain.
The Effects of Previous Abdominal Operations and Intraperitoneal Adhesions on the Outcome of Peritoneal Dialysis Catheters
Authors: Keshvari Amir , Fazeli Mohammad Sadegh , Meysamie Alipasha , Seifi Sepideh , Taromloo Mohammad Kazem Nouri 
Published: February 2010

Background Patients with previous history of abdominal operations are sometimes excluded from consideration for peritoneal dialysis because of concerns for increased risk of complications during the implantation procedure and inadequate dialysis due to reduced peritoneal surface area. Employing a laparoscopic approach, we compared the outcome of peritoneal dialysis catheters in 2 groups of patients with and without intra-abdominal adhesions. Methods All data in this report were recorded prospectively. Revision-free and overall survival of catheters, the incidence of mechanical and infectious complication, and surgical revision rates were compared between the 2 groups. Results In 217 successful catheter implantations, there was a history of previous abdominal surgery in 42.9% of procedures; only 26.9% of them had intraperitoneal adhesions; 2.8% of patients without history of previous abdominal surgery had intraperitoneal adhesions. There were no significant differences between the 2 groups for 1- and 2-year revision-free and overall catheter survival, mechanical dysfunction, infectious complications, or surgical revision rates. Conclusion History of previous abdominal surgery should not be used to judge the eligibility of patients for peritoneal dialysis. Laparoscopic placement is the best way to ensure optimal catheter outcomes equivalent to patients without previous abdominal surgery.
Angiotensin Receptor Blocker Telmisartan Improves Insulin Sensitivity in Peritoneal Dialysis Patients
Authors: Cioni Antonio , Sordini Caterina , Cavallini Ivo , Bigazzi Roberto , Campese Vito M. 
Published: February 2010

Background Insulin resistance (IR) is common among patients on dialysis and is worse among patients on peritoneal dialysis (PD) than among patients on hemodialysis. In this study we tested the hypothesis that administration of telmisartan, an angiotensin II type 1 receptor antagonist, might improve insulin sensitivity in patients on PD. Method This was a crossover study of 30 nondiabetic patients with end-stage renal disease being treated with PD. Group A patients ( n = 15) received telmisartan and other antihypertensive drugs for 4 months, followed by 4 months without telmisartan. Group B patients ( n = 15) received their usual treatment for 4 months, followed by 4 months of treatment with telmisartan. Blood glucose and serum insulin levels were monitored and homeostasis model assessment method for IR (HOMA-IR) was calculated. Results Treatment with telmisartan had no significant impact on serum glucose, potassium, and bicarbonate levels. However, telmisartan significantly reduced serum insulin levels and the HOMA index in groups A and B. Conclusion This study demonstrated that telmisartan, an angiotensin receptor type 1 antagonist, may effectively improve insulin sensitivity as measured by HOMA in patients treated with PD.
Comparison of the Multiple-Aliquot and Batch Methods of Monitoring Peritoneal Dialysis Adequacy in Patients
Authors: Lyon Andrew W. , James Janice , Lemaire Christine , Culleton Bruce 
Published: February 2010

Background Effluent fluid is analyzed to determine Kt/V urea and creatinine clearance as measures of adequacy of peritoneal dialysis. To avoid the physical mixing of fluids and to minimize handling of full effluent bags, a multiple-aliquot method of sampling was developed and compared to the traditional batch method. Methods The batch method and the multiple-aliquot method were performed for 31 consecutive patients. Pooled fluid urea and creatinine measurements were determined for each method. PD Adequest 2.0 (Baxter Healthcare, Deerfield, IL, USA) was used to derive calculated peritoneal dialysis parameters. Results Urea dialysate levels, calculated weekly urea clearances, protein catabolic rate, and Kt/V were not statistically different ( p > 0.05) between the 2 methods. Dialysate creatinine and creatinine clearance with the 2 methods were statistically distinct but the differences were not clinically important. The processing time per set of patient effluent bags was reduced from 45 to 18 minutes, handling of the bags was minimized, and error associated with inadequate mixing of pooled fluids was avoided. Conclusion The multiple-aliquot method generates accurate and timely results to assess peritoneal dialysis prescription adequacy while reducing staff effort.
A Prospective Randomized Study Comparing Tenckhoff Catheters Inserted using the Triple Incision Method with Standard Swan Neck Catheters
Authors: Yip Terence , Lui Sing Leung , Tse Kai Chung , Xu Hong , Ng Flora S.K. , Cheng Suk Wai , Chan Tak Mao , Lai Kar Neng , Lo Wai Kei 
Published: February 2010

Background and Objective The downward directed exit of the swan neck catheter may decrease the risk of exit-site infection (ESI). The percentage of migrations of the swan neck catheter seems to be less than the conventional Tenckhoff catheter and the swan neck catheter is more expensive and cannot be manipulated by guidewire technique if tip migration occurs. In this study, the conventional Tenckhoff catheter was used. The straight tunnel was converted to an arcuate one using the triple incision method, resulting in a downward directed exit. The arcuate tunnel was created by passing the catheter through an additional incision located between the paramedian incision and the exit site. We compared the infective and mechanical complications of the Tenckhoff catheter with a downward exit, implanted using the triple incision method, with the swan neck catheter. Patients and Methods 101 new peritoneal dialysis patients were prospectively randomized to receive either the Tenckhoff catheter with a downward exit, implanted using the triple incision method, or the swan neck catheter. Each patient was followed up for 24 months. 50 patients were in the triple incision method group (TIMG) and 51 were in the swan neck catheter group (SNCG). Results Over a mean period of 18.9 ± 8.0 months of follow-up, ESI occurred in 35 patients (70%) in TIMG and 37 patients (72.5%) in SNCG ( p = 0.83). The ESI rates were 0.71 and 1.0 episodes/catheter-year in TIMG and SNCG respectively ( p = 0.21). The peritonitis rates were similar in the 2 groups (0.64 episodes/year in TIMG and 0.68 episodes/year in SNCG, p = 0.47). More patients in TIMG had tip migration [15 patients (30%) in TIMG vs 10 patients (19.6%) in SNCG] but the difference was not statistically significant. Repositioning of the catheter by guidewire manipulation was successful in patients in TIMG but not in SNCG. Overall catheter survival at 12 and 24 months was 95% and 83% in TIMG and 93% and 79% in SNCG respectively ( p = 0.72). Conclusion By using the conventional Tenckhoff catheter with a downward exit created using the triple incision method, high catheter survival rates with infective and mechanical complication rates similar to those of the swan neck catheter can be achieved. The triple incision method has the additional advantages of lower cost and the catheter can be manipulated by guidewire technique if tip migration occurs.