bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergistic Combination of Chitosan Acetate with Nanoparticle Silver as a Topical Antimicrobial: Efficacy against Bacterial Burn Infections
Authors: Huang Liyi , Dai Tianhong , Xuan Yi , Tegos George P. , Hamblin Michael R. 
Published: April 2011

ABSTRACT

Chitosan and nanoparticle silver are both materials with demonstrated antimicrobial properties and have been proposed singly or in combination as constituents of antimicrobial burn dressings. Here, we show that they combine synergistically to inhibit the
in vitro
growth of Gram-positive methicillin-resistant
Staphylococcus aureus
(MRSA) and Gram-negative bacteria (
Pseudomonas aeruginosa
,
Proteus mirabilis
, and
Acinetobacter baumannii
), as judged by bioluminescence monitoring and isobolographic analysis, and also produce synergistic killing after 30 min of incubation, as measured by a CFU assay. The hypothesized explanation involves chitosan-mediated permeabilization of bacterial cells, allowing better penetration of silver ions into the cell. A dressing composed of freeze-dried chitosan acetate incorporating nanoparticle silver was compared with a dressing of chitosan acetate alone in an
in vivo
burn model infected with bioluminescent
P. aeruginosa
. The survival rates of mice treated with silver-chitosan or regular chitosan or left untreated were 64.3% (
P
= 0.0082 versus regular chitosan and
P
= 0.0003 versus the control), 21.4%, and 0%, respectively. Most of the fatalities occurred between 2 and 5 days postinfection. Silver-chitosan dressings effectively controlled the development of systemic sepsis, as shown by blood culture. These data suggest that a dressing combining chitosan acetate with silver leads to improved antimicrobial efficacy against fatal burn infections.
Shift in Ribonucleotide Reductase Gene Expression in Pseudomonas aeruginosa during Infection
Authors: Sjöberg Britt-Marie , Torrents Eduard 
Published: April 2011

ABSTRACT

The roles of different ribonucleotide reductases (RNRs) in bacterial pathogenesis have not been studied systematically. In this work we analyzed the importance of the different
Pseudomonas aeruginosa
RNRs in pathogenesis using the
Drosophila melanogaster
host-pathogen interaction model.
P. aeruginosa
codes for three different RNRs with different environmental requirements. Class II and III RNR chromosomal mutants exhibited reduced virulence in this model. Translational reporter fusions of RNR gene
nrdA
,
nrdJ
, or
nrdD
to the green fluorescent protein were constructed to measure the expression of each class during the infection process. Analysis of the
P. aeruginosa
infection by flow cytometry revealed increased expression of
nrdJ
and
nrdD
and decreased
nrdA
expression during the infection process. Expression of each RNR class fits with the pathogenicities of the chromosomal deletion mutants. An extended understanding of the pathogenicity and physiology of
P. aeruginosa
will be important for the development of novel drugs against infections in cystic fibrosis patients.
Smoke-free college campuses: no ifs, ands or toxic butts: Figure 1
Authors: Sawdey Michael , Lindsay Ryan P , Novotny Thomas E 
Published: April 2011

ObjectiveTo better estimate the burden of toxic cigarette butt waste and create awareness of the hazardous nature of cigarette butts on two large university campuses in San Diego by organizing and conducting student cigarette butt clean-up activities.MethodsTwo separate campus-wide clean-ups were conducted by student volunteers at San Diego State University (SDSU) and at University of California San Diego (UCSD) between April and July 2010.ResultsIn 1 h, 63 volunteers at SDSU collected 23 885 butts; 6525 cigarette butts were collected in 1 h by 17 volunteers at UCSD. The average number of cigarette butts picked up per individual was 379.1 at SDSU and 383.8 at UCSD (range 25–1030 per volunteer).ConclusionsThe amount of cigarette waste on college campuses nationally may be quite substantial given the many thousands of cigarette butts gathered at each of the San Diego institutions. In just 10 s on average a volunteer could locate, walk to, pick up and put a cigarette butt in the collection bag and then begin looking for another discarded butt, indicating the saturation of cigarette butts on campus. Smoke-free policies on campus could have far-reaching effects not only in reducing smoking behaviour on campus and ground clean-up costs, but also on the environment. Campus cigarette waste clean-ups can be utilized to call attention to the issue of cigarette butt waste in the environment.
Toxicity of cigarette butts, and their chemical components, to marine and freshwater fish
Authors: Slaughter Elli , Gersberg Richard M , Watanabe Kayo , Rudolph John , Stransky Chris , Novotny Thomas E 
Published: April 2011

BackgroundCigarette butts are the most common form of litter, as an estimated 4.5 trillion cigarette butts are thrown away every year worldwide. Many chemical products are used during the course of growing tobacco and manufacturing cigarettes, the residues of which may be found in cigarettes prepared for consumption. Additionally, over 4000 chemicals may also be introduced to the environment via cigarette particulate matter (tar) and mainstream smoke.MethodsUsing US Environmental Protection Agency standard acute fish bioassays, cigarette butt-derived leachate was analysed for aquatic toxicity. Survival was the single endpoint and data were analysed using Comprehensive Environmental Toxicity Information System to identify the LC50 of cigarette butt leachate to fish.ResultsThe LC50 for leachate from smoked cigarette butts (smoked filter + tobacco) was approximately one cigarette butt/l for both the marine topsmelt (Atherinops affinis) and the freshwater fathead minnow (Pimephales promelas). Leachate from smoked cigarette filters (no tobacco), was less toxic, with LC50 values of 1.8 and 4.3 cigarette butts/l, respectively for both fish species. Unsmoked cigarette filters (no tobacco) were also found to be toxic, with LC50 values of 5.1 and 13.5 cigarette butts/l, respectively, for both fish species.ConclusionToxicity of cigarette butt leachate was found to increase from unsmoked cigarette filters (no tobacco) to smoked cigarette filters (no tobacco) to smoked cigarette butts (smoked filter + tobacco). This study represents the first in the literature to investigate and affirm the toxicity of cigarette butts to fish, and will assist in assessing the potential ecological risks of cigarette butts to the aquatic environment.
Analysis of metals leached from smoked cigarette litter
Authors: Moerman J W , Potts G E 
Published: April 2011

BackgroundLittered cigarette butts represent potential point sources for environmental contamination. In areas with substantial amounts of cigarette litter, environmental hazards may arise as chemical components are leached from the filters and smoked tobacco.ObjectiveThe three main aims of this study were: (1) to quantify the amount of Al, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Sr, Ti and Zn leached from cigarette butts, (2) to determine the relationship between the pH of the aqueous soaking solution and metal concentration leached and (3) to determine the relationship between the period of soaking in aqueous solution and metal concentration leached.MethodsSmoked cigarette butts and unsmoked cigarettes were added to phials containing aqueous solutions of pH 4.00, 5.00 and 6.00 (±0.05). The metal concentration of the resultant leachates was measured via inductively coupled plasma optical emission spectroscopy (ICP-OES) 1 day, 7 days and 34 days after sample addition.ResultsAll metals were detected in leachates 1 day after sample addition (with the exception of Cd) and were released at varying rates. No clear relationship between pH within the range typical of precipitation and metal concentration leached was observed.ConclusionsBased on the gradual release of multiple metals over the full 34-day study period, cigarette litter was found to be a point source for metal contamination. The apparent rapid leaching of other metals may increase the risk of acute harm to local organisms.
Menthol cigarettes and smoking initiation: a tobacco industry perspective
Authors: Klausner Kim 
Published: April 2011

ObjectivesTo determine what the tobacco industry knew about menthol cigarettes and the initiation of smoking.MethodsBased on Food and Drug Administration staff-supplied research questions we used a snowball sampling strategy to search the Legacy Tobacco Documents Library (http://legacy.library.ucsf.edu) between February and April 2010. Of the approximately 11 million documents available in the LTDL, the iterative searches returned tens of thousands of results. Researchers reviewed 2634 documents and 128 were deemed relevant to one or more of the research questions.ResultsThe documents show that menthol is added to cigarettes in part because it is known to be an attractive feature to inexperienced smokers who perceive menthol cigarettes as less harsh and easier to smoke and because of their availability from friends and family. Second, the tobacco industry found that some youths smoke menthols because they perceive them to be less harmful than non-menthol cigarettes. A key product design issue concerns whether to increase brand menthol levels to appeal to the taste preferences of long-term menthol smokers or keep menthol levels lower to appeal to inexperienced smokers. Marketing studies showed that the companies carefully researched the menthol segment of the market in order to recruit younger smokers to their brands. The industry tracked menthol cigarette usage by age, gender and race to inform product development and marketing decisions.ConclusionsMenthol is a prominent design feature used by cigarette manufacturers to attract and retain new, younger smokers.
Direct disease-inducing effects of menthol through the eyes of tobacco companies
Authors: Salgado M Victoria , Glantz Stanton A 
Published: April 2011

ObjectiveMenthol is an important additive in most tobacco products and is an identifying characteristic of many brands. We assessed tobacco companies' research on direct disease-inducing effects of menthol and menthol cigarettes.MethodsA search was conducted among documents included in the Legacy Tobacco Documents Library. Relevant documents addressed subject areas such as pharmacology, short-term and long-term effects and biomarkers of smoking exposure.ResultsThe documents contain little internal industry research on the disease-inducing effects of menthol. Most information in the tobacco industry documents are reviews of the published biomedical literature, from which the companies concluded that menthol did not have any direct disease-inducing effects. Evidence that contradicted this conclusion was downplayed. Except for one study, there was no evidence of the companies following up on positive findings in the literature with their own studies. In one case, results were presented at a public scientific meeting concluding that ‘There were no effects from addition of menthol to test or reference cigarettes’, when a company's internal pathology analysis contradicted this statement.ConclusionThe available industry documents suggest that tobacco companies conducted little research on the potential disease-inducing effects of menthol and did not pursue studies that suggested adverse effects.
Menthol's potential effects on nicotine dependence: a tobacco industry perspective
Authors: Yerger Valerie B 
Published: April 2011

ObjectiveTo examine what the tobacco industry knows about the potential effects menthol may have on nicotine dependence.MethodsA snowball strategy was used to systematically search the Legacy Tobacco Documents Library (http://legacy.library.ucsf.edu/) between 22 February and 29 April, 2010. Of the approximately 11 million documents available in the Legacy Tobacco Documents Library, the iterative searches returned tens of thousands of results. We qualitatively analysed a final collection of 309 documents relevant the effects of menthol on nicotine dependence.ResultsThe tobacco industry knows that menthol overrides the harsh taste of tobacco and alleviates nicotine's irritating effects, synergistically interacts with nicotine, stimulates the trigeminal nerve to elicit a ‘liking’ response for a tobacco product, and makes low tar, low nicotine tobacco products more acceptable to smokers than non-mentholated low delivery products.ConclusionMenthol is not only used in cigarettes as a flavour additive; tobacco companies know that menthol also has sensory effects and interacts with nicotine to produce tobacco products that are easier to smoke, thereby making it easier to expose smokers, especially those who are new and uninitiated, to the addictive power of nicotine.
Geographic patterns of cigarette butt waste in the urban environment: Figure 1
Authors: Marah Maacah , Novotny Thomas E 
Published: April 2011

BackgroundThis reports the initial phase of a study to quantify the spatial pattern of cigarette butt waste in an urban environment.MethodsGeographic Information Systems (GIS) was used to create a weighted overlay analysis model which was then applied to the locations of businesses where cigarettes are sold or are likely to be consumed and venues where higher concentrations of butts may be deposited. The model's utility was tested using a small-scale litter audit in three zip codes of San Diego, California.ResultsWe found that cigarette butt waste is highly concentrated around businesses where cigarettes are sold or consumed. The mean number of butts for predicted high waste sites was 38.1 (SD 18.87), for predicted low waste sites mean 4.8 (SD 5.9), p<0.001.ConclusionsCigarette butt waste is not uniformly distributed in the urban environment, its distribution is linked to locations and patterns of sales and consumption. A GIS and weighted overlay model may be a useful tool in predicting urban locations of greater and lesser amounts of cigarette butt waste. These data can in turn be used to develop economic cost studies and plan mitigation strategies in urban communities.
Phosphorylation of Serine 68 of Twist1 by MAPKs Stabilizes Twist1 Protein and Promotes Breast Cancer Cell Invasiveness
Authors: Hong Jun , Zhou Jian , Fu Junjiang , He Tao , Qin Jun , Wang Li , Liao Lan , Xu Jianming 
Published: April 2011

Abstract
Twist1, a basic helix–loop–helix transcription factor, promotes breast tumor cell epithelial–mesenchymal transition (EMT), invasiveness, and metastasis. However, the mechanisms responsible for regulating Twist1 stability are unknown in these cells. We identified the serine 68 (Ser 68) as a major phosphorylation site of Twist1 by mass spectrometry and with specific antibodies. This Ser 68 is phosphorylated by p38, c-Jun N-terminal kinases (JNK), and extracellular signal-regulated kinases1/2 in vitro, and its phosphorylation levels positively correlate with Twist1 protein levels in human embryonic kidney 293 and breast cancer cells. Prevention of Ser 68 phosphorylation by an alanine (A) mutation (Ser 68A) dramatically accelerates Twist1 ubiquitination and degradation. Furthermore, activation of mitogen-activated protein kinases (MAPK) by an active Ras protein or TGF-β treatment significantly increases Ser 68 phosphorylation and Twist1 protein levels without altering Twist1 mRNA expression, whereas blocking of MAPK activities by either specific inhibitors or dominant negative inhibitory mutants effectively reduces the levels of both induced and uninduced Ser 68 phosphorylation and Twist protein. Accordingly, the mammary epithelial cells expressing Twist1 exhibit much higher degrees of EMT and invasiveness on stimulation with TGF-β or the active Ras and paclitaxel resistance compared with the same cells expressing the Ser 68A-Twist1 mutant. Importantly, the levels of Ser 68 phosphorylation in the invasive human breast ductal carcinomas positively correlate with the levels of Twist1 protein and JNK activity and are significantly higher in progesterone receptor–negative and HER2-positive breast cancers. These findings suggest that activation of MAPKs by tyrosine kinase receptors and Ras signaling pathways may substantially promote breast tumor cell EMT and metastasis via phoshorylation and stabilization of Twist1. Cancer Res; 71(11); 3980–90. ©2011 AACR.
Safety and Tolerability of Atopaxar in the Treatment of Patients With Acute Coronary Syndromes
Authors: O'Donoghue Michelle L. , Bhatt Deepak L. , Wiviott Stephen D. , Goodman Shaun G. , Fitzgerald Desmond J. , Angiolillo Dominick J. , Goto Shinya , Montalescot Gilles , Zeymer Uwe , Aylward Philip E. , Guetta Victor , Dudek Dariusz , Ziecina Rafal , Contant Charles F. , Flather Marcus D. 
Published: April 2011

Background—
Atopaxar (E5555) is a reversible protease-activated receptor-1 thrombin receptor antagonist that interferes with platelet signaling. The primary objective of the Lessons From Antagonizing the Cellular Effects of Thrombin–Acute Coronary Syndromes (LANCELOT—ACS) trial was to evaluate the safety and tolerability of atopaxar in patients with ACS.

Methods and Results—

Six hundred and three subjects were randomized within 72 hours of non–ST-elevation ACS to 1 of 3 doses of atopaxar (400-mg loading dose followed by 50, 100, or 200 mg daily) or matching placebo. The incidence of Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) major or minor bleeding did not differ significantly between the combined atopaxar and placebo groups (3.08% versus 2.17%, respectively;
P
=0.63), and there was no dose-related trend (
P
=0.80). The incidence of CURE major bleeding was numerically higher in the atopaxar group compared with the placebo group (1.8% versus 0%;
P
=0.12). The incidence of cardiovascular death, myocardial infarction, stroke, or recurrent ischemia was similar between the atopaxar and placebo arms (8.03% versus 7.75%;
P
=0.93). The incidence of CV death, MI, or stroke was 5.63% in the placebo group and 3.25% in the combined atopaxar group (
P
=0.20). Dose-dependent trends for efficacy were not seen. Atopaxar significantly reduced ischemia on continuous ECG monitoring (Holter) at 48 hours compared with placebo (relative risk, 0.67;
P
=0.02). Transient dose-dependent transaminase elevation and relative QTc prolongation were observed with the highest doses of atopaxar.

Conclusion—
In patients after ACS, atopaxar significantly reduced early ischemia on Holter monitoring without a significant increase in major or minor bleeding. Larger trials are required to fully establish the efficacy and safety of atopaxar.

Clinical Trial Registration—

URL:
http://www.ClinicalTrials.gov
. Unique identifier: NCT00548587.
Probabilistic Estimates of Transient Climate Sensitivity Subject to Uncertainty in Forcing and Natural Variability
Authors: Padilla Lauren E. , Vallis Geoffrey K. , Rowley Clarence W. 
Published: April 2011

Abstract
In this paper, the authors address the impact of uncertainty on estimates of transient climate sensitivity (TCS) of the globally averaged surface temperature, including both uncertainty in past forcing and internal variability in the climate record. This study provides a range of probabilistic estimates of the TCS that combine these two sources of uncertainty for various underlying assumptions about the nature of the uncertainty. The authors also provide estimates of how quickly the uncertainty in the TCS may be expected to diminish in the future as additional observations become available. These estimates are made using a nonlinear Kalman filter coupled to a stochastic, global energy balance model, using the filter and observations to constrain the model parameters. This study verifies that model and filter are able to emulate the evolution of a comprehensive, state-of-the-art atmosphere–ocean general circulation model and to accurately predict the TCS of the model, and then apply the methodology to observed temperature and forcing records of the twentieth century.
For uncertainty assumptions best supported by global surface temperature data up to the present time, this paper finds a most likely present-day estimate of the transient climate sensitivity to be 1.6 K, with 90% confidence the response will fall between 1.3 and 2.6 K, and it is estimated that this interval may be 45% smaller by the year 2030. The authors calculate that emissions levels equivalent to forcing of less than 475 ppmv CO2 concentration are needed to ensure that the transient temperature response will not exceed 2 K with 95% confidence. This is an assessment for the short-to-medium term and not a recommendation for long-term stabilization forcing; the equilibrium temperature response to this level of CO2 may be much greater. The flat temperature trend of the last decade has a detectable but small influence on TCS. This study describes how the results vary if different uncertainty assumptions are made and shows they are robust to variations in the initial prior probability assumptions.
Moist Thermodynamics of the Madden–Julian Oscillation in a Cloud-Resolving Simulation
Authors: Hagos Samson , Leung L. Ruby 
Published: April 2011

Abstract
The moist thermodynamic processes that determine the time scale and energy of the Madden–Julian oscillation (MJO) are investigated using moisture and eddy available potential energy budget analyses on a cloud-resolving simulation. Two MJO episodes observed during the winter of 2007/08 are realistically simulated. During the inactive phase, moisture supplied by meridional moisture convergence and boundary layer diffusion generates shallow and congestus clouds that moisten the lower troposphere while horizontal mixing tends to dry it. As the lower troposphere is moistened, it becomes a source of moisture for the subsequent deep convection during the MJO active phase. As the active phase ends, the lower troposphere dries out primarily by condensation and horizontal divergence that dominates over the moisture supply by vertical transport. In the simulation, the characteristic time scales of convective vertical transport, mixing, and condensation of moisture in the midtroposphere are estimated to be about 2 days, 4 days, and 20 h respectively. The small differences among these time scales result in an effective time scale of MJO moistening of about 25 days, half the period of the simulated MJO. Furthermore, various cloud types have a destabilizing or damping effect on the amplitude of MJO temperature signals, depending on their characteristic latent heating profile and its temporal covariance with the temperature. The results are used to identify possible sources of the difficulties in simulating MJO in low-resolution models that rely on cumulus parameterizations.
Improving Land Data Assimilation Performance with a Water Budget Constraint
Authors: Yilmaz M. Tugrul , DelSole Timothy , Houser Paul R. 
Published: April 2011

AbstractA weak constraint is introduced in ensemble Kalman filters to reduce the water budget imbalance that occurs in land data assimilation. Two versions of the weakly constrained filter, called the weakly constrained ensemble Kalman filter (WCEnKF) and the weakly constrained ensemble transform Kalman filter (WCETKF), are proposed. The strength of the weak constraint is adaptive in the sense that it depends on the statistical characteristics of the forecast ensemble. The resulting filters are applied to assimilate synthetic observations generated by the Noah land surface model over the Red Arkansas River basin. The data assimilation experiments demonstrate that, for all tested scenarios, the constrained filters produce analyses with nearly the same accuracy as unconstrained filters, but with much smaller water balance residuals than unconstrained filters.