Publications by authors named "Scott Pierce"

20 Publications

  • Page 1 of 1

Point of Care Ultrasound in the Diagnosis of Necrotizing Fasciitis.

Am J Emerg Med 2022 Jan 29;51:397-400. Epub 2021 Oct 29.

University of California Irvine, Department of Emergency Medicine, United States.

Background: Necrotizing fasciitis (NF) is a severe, life-threatening soft tissue infection requiring prompt diagnosis and immediate surgical debridement. Imaging, including a computed tomography (CT) scan, can often aid in the diagnosis, though it can prolong time to treatment and diagnosis. Point-of-care ultrasound (POCUS) is often used in the ED to identify soft tissue infections. The objective of this study is to evaluate the use of POCUS to identify NF in patients presenting to the emergency department.

Methods: We prospectively enrolled patients who presented to the emergency department (ED) with suspected soft tissue infection who received a computed tomography and/or surgical consult. POCUS images of the suspected site of infection were obtained by the emergency medicine physician and interpreted based on sonographic findings of NF. These findings were compared with CT scan or surgical impression.

Results: We enrolled 64 patients in this study. Eight were determined to be at high risk of having NF based on CT scan and/or surgical impression. All of these patients also had POCUS images interpreted as concerning for NF. Furthermore, 56 patients were classified as being low risk for having NF based on CT scan and/or surgical impression. All but one of these patients had POCUS images interpreted as not concerning for NF.

Conclusions: Our data indicates that POCUS can be used to identify NF with a high sensitivity and specificity.
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http://dx.doi.org/10.1016/j.ajem.2021.10.033DOI Listing
January 2022

Youth Sport and COVID-19: Contextual, Methodological, and Practical Considerations.

Front Sports Act Living 2020 9;2:584252. Epub 2020 Oct 9.

PLAYS Research Group, School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada.

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http://dx.doi.org/10.3389/fspor.2020.584252DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7739668PMC
October 2020

Peptide-Ruthenium Conjugate as an Efficient Photosensitizer for the Inactivation of Multidrug-Resistant Bacteria.

Inorg Chem 2020 Oct 29;59(20):14866-14870. Epub 2020 Sep 29.

Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United States.

Antimicrobial photodynamic therapy (APDT) has gained increased attention because of its broad spectrum activity and lower likelihood to elicit bacterial resistance. Although many photosensitizers excel at eradicating Gram-positive bacterial infections, they are generally less potent when utilized against Gram-negative bacteria. We hypothesized that conjugating the DNA-targeting, antimicrobial peptide buforin II to a metal-based photosensitizer would result in a potent APDT agent. Herein, we present the synthesis and characterization of a buforin II-[Ru(bpy)] bioconjugate (). The submicromolar activity of against the multidrug-resistant strains AR 0114 and Naval-17 indicates strong synergy between the ruthenium complex and buforin II. Our mechanistic studies point to an increased rate of DNA damage by compared to [Ru(bpy)]. These results suggest that conjugating metal complexes to antimicrobial peptides can lead to potent antimicrobial agents.
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http://dx.doi.org/10.1021/acs.inorgchem.0c02491DOI Listing
October 2020

Making the Healthy Choice the Easy Choice: Online Training in Policy, Systems, and Environmental Approaches.

J Nutr Educ Behav 2020 12 3;52(12):1166-1170. Epub 2020 Sep 3.

Division of Nutritional Sciences, Cornell University, Ithaca, NY.

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http://dx.doi.org/10.1016/j.jneb.2020.07.008DOI Listing
December 2020

A Potent Host Defense Peptide Triggers DNA Damage and Is Active against Multidrug-Resistant Gram-Negative Pathogens.

ACS Infect Dis 2020 05 17;6(5):1250-1263. Epub 2020 Apr 17.

Department of Chemistry, University of Connecticut, 55 N. Eagleville Road, Storrs, Connecticut 06269, United States.

Gram-negative bacteria are some of the biggest threats to public health due to a large prevalence of antibiotic resistance. The difficulty in treating bacterial infections, stemming from their double membrane structure combined with efflux pumps in the outer membrane, has resulted in a much greater need for antimicrobials with activity against these pathogens. Tunicate host defense peptide (HDP), Clavanin A, is capable of not only inhibiting Gram-negative growth but also potentiating activity in the presence of Zn(II). Here, we provide evidence that the improvements of Clavanin A activity in the presence of Zn(II) are due to its novel mechanism of action. We employed TD172 (Δ) and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to show that DNA damage occurs upon treatment with Clavanin A. assays demonstrated that Zn(II) ions are required for the nuclease activity of the peptide. The quantum mechanics/molecular mechanics (QM/MM) calculations were used to investigate the mechanism of DNA damage. In the rate-determining step of the proposed mechanism, due to its Lewis acidity, the Zn(II) ion activates the scissile P-O bond of DNA and creates a hydroxyl nucleophile from a water molecule. A subsequent attack by this group to the electrophilic phosphorus cleaves the scissile phosphoester bond. Additionally, we utilized bacterial cytological profiling (BCP), circular dichroism (CD) spectroscopy in the presence of lipid vesicles, and surface plasmon resonance combined with electrical impedance spectroscopy in order to address the apparent discrepancies between our results and the previous studies regarding the mechanism of action of Clavanin A. Finally, our approach may lead to the identification of additional Clavanin A like HDPs and promote the development of antimicrobial peptide based therapeutics.
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http://dx.doi.org/10.1021/acsinfecdis.0c00051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7772950PMC
May 2020

Phagosomal Copper-Promoted Oxidative Attack on Intracellular Mycobacterium tuberculosis.

ACS Infect Dis 2018 11 6;4(11):1623-1634. Epub 2018 Sep 6.

Department of Chemistry , University of Connecticut , 55 N. Eagleville Road , Storrs , Connecticut 06269 , United States.

Copper (Cu) ions are critical in controlling bacterial infections, and successful pathogens like Mycobacterium tuberculosis (Mtb) possess multiple Cu resistance mechanisms. We report, as proof of concept, that a novel Cu hypersensitivity phenotype can be generated in mycobacteria, including Mtb, through a peptide, DAB-10, that is able to form reactive oxygen species (ROS) following Cu-binding. DAB-10 induces intramycobacterial oxidative stress in a Cu-dependent manner in vitro and during infection. DAB-10 penetrates murine macrophages and encounters intracellular mycobacteria. Significant intracellular Cu-dependent protection was observed when Mtb-infected macrophages were treated with DAB-10 alongside a cell-permeable Cu chelator. Treatment with the Cu chelator reversed the intramycobacterial oxidative shift induced by DAB-10. We conclude that DAB-10 utilizes the pool of phagosomal Cu ions in the host-Mtb interface to augment the mycobactericidal activity of macrophages while simultaneously exploiting the susceptibility of Mtb to ROS. DAB-10 serves as a model with which to develop next-generation, multifunctional antimicrobials.
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http://dx.doi.org/10.1021/acsinfecdis.8b00171DOI Listing
November 2018

Choose Health: Food, Fun, and Fitness Youth Curriculum Promotes Positive Behaviors.

J Nutr Educ Behav 2018 10 21;50(9):924-930. Epub 2017 Nov 21.

Division of Nutritional Sciences, Cornell University, Ithaca, NY.

Objective: Evaluate whether participation in Choose Health: Food, Fun, and Fitness (CHFFF), a hands-on, experiential curriculum aimed at third- to sixth-graders, resulted in improvements in the targeted obesity and chronic disease prevention behaviors.

Methods: The researchers evaluated CHFFF in low-income youth participating in 2 federal programs in New York State during 2013-2015. Food and activity behaviors were assessed using the Expanded Food and Nutrition Education Program third- through fifth- and sixth- through eighth-grade pre-post surveys, along with 2 sets of added CHFFF-specific items completed by subsamples. Educators trained in CHFFF had youth complete the surveys as they delivered the curriculum, primarily in schools and after-school programs.

Results: Paired t tests showed significant (P < .01) positive changes before to after CHFFF education for consumption of vegetables, fruits, sweetened drinks, nutrition label reading, and other food and activity behaviors.

Conclusions And Implications: Results provide practice-based evidence that CHFFF promotes positive behavior change in participating youth.
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http://dx.doi.org/10.1016/j.jneb.2017.09.008DOI Listing
October 2018

Exploration of the Innate Immune System of Styela clava: Zn Binding Enhances the Antimicrobial Activity of the Tunicate Peptide Clavanin A.

Biochemistry 2017 03 3;56(10):1403-1414. Epub 2017 Mar 3.

Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.

Tunicates have been used as primitive models for understanding cell-mediated and humoral immunity. Clavanin A (ClavA) is one member of a family of antimicrobial peptides produced by the solitary tunicate Styela clava. In this work, we demonstrate that ClavA utilizes Zn ions to potentiate its antimicrobial activity not only by reducing the concentration at which the peptide inhibits the growth of bacteria but also by increasing the rate of killing. Membrane depolarization, β-galactosidase leakage, and potassium leakage assays indicate that ClavA is membrane active, forms small pores, but induces cell death by targeting an intracellular component. ClavA and ClavA-Zn added to Escherichia coli and imaged by confocal microscopy translocate across the cell membrane. E. coli mutants lacking the functional Zn import system are less susceptible to ClavA, suggesting that the synergistic activity between ClavA and Zn has a cytoplasmic target, which is further supported by its nucleolytic activity. Overall, these studies identify a remarkable new mechanism by which zinc contributes to the immune response in the tunicate S. clava.
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http://dx.doi.org/10.1021/acs.biochem.6b01046DOI Listing
March 2017

Anatomical characterization of subcortical descending projections to the inferior colliculus in mouse.

J Comp Neurol 2017 Mar 21;525(4):885-900. Epub 2016 Oct 21.

Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

Descending projections from the thalamus and related structures to the midbrain are evolutionarily highly conserved. However, the basic organization of this auditory thalamotectal pathway has not yet been characterized. The purpose of this study was to obtain a better understanding of the anatomical and neurochemical features of this pathway. Analysis of the distributions of retrogradely labeled cells after focal injections of retrograde tracer into the inferior colliculus (IC) of the mouse revealed that most of the subcortical descending projections originated in the brachium of the IC and the paralaminar portions of the auditory thalamus. In addition, the vast majority of thalamotectal cells were found to be negative for the calcium-binding proteins calbindin, parvalbumin, or calretinin. Using two different strains of GAD-GFP mice, as well as immunostaining for GABA, we found that a subset of neurons in the brachium of the IC is GABAergic, suggesting that part of this descending pathway is inhibitory. Finally, dual retrograde injections into the IC and amygdala plus corpus striatum as well into the IC and auditory cortex did not reveal any double labeling. These data suggest that the thalamocollicular pathway comprises a unique population of thalamic neurons that do not contain typical calcium-binding proteins and do not project to other paralaminar thalamic forebrain targets, and that a previously undescribed descending GABAergic pathway emanates from the brachium of the IC. J. Comp. Neurol. 525:885-900, 2017. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/cne.24106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5222726PMC
March 2017

Durable Disease Control with MEK Inhibition in a Patient with NRAS-mutated Atypical Chronic Myeloid Leukemia.

Cureus 2015 Dec 17;7(12):e414. Epub 2015 Dec 17.

Knight Cancer Institute, Oregon Health & Science University ; Howard Hughes Medical Institute Investigator Program, Howard Hughes Medical Institute ; Division of Hematology & Medical Oncology, Oregon Health & Science University ; Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University.

Atypical chronic myeloid leukemia (aCML) and chronic neutrophilic leukemia (CNL) are rare hematologic neoplasms characterized by leukocytosis and a hypercellular bone marrow. Although recurrent mutations in the colony-stimulating factor 3 receptor (CSF3R) are frequently observed in patients with (CNL), the mutational landscape in (aCML) is less well-defined. In this report, we describe an 81-year-old male who was diagnosed with aCML. He presented with leukocytosis and anemia but no significant clinical symptoms. Standard laboratory studies revealed the absence of the Philadelphia chromosome. Massively parallel sequencing demonstrated no mutations in CSF3R, but the presence of a heterozygous NRAS-G12D variant (47% allele frequency). The patient was started on treatment with trametinib, an MEK1/2 inhibitor with Food and Drug Administration approval for malignant melanoma. Therapy with trametinib resulted in exceptional improvements in his blood counts and continued disease control with 14 months of follow-up. This case highlights the need for clinical trials evaluating the safety and efficacy of MEK1/2 as a therapeutic target for the treatment of patients with NRAS-mutated aCML/CNL.
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http://dx.doi.org/10.7759/cureus.414DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4725740PMC
December 2015

Copper-binding tripeptide motif increases potency of the antimicrobial peptide Anoplin via Reactive Oxygen Species generation.

Biochem Biophys Res Commun 2015 Jan 4;456(1):446-51. Epub 2014 Dec 4.

Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. Electronic address:

Antimicrobial peptides (AMPs) are broad spectrum antimicrobial agents that act through diverse mechanisms, this characteristic makes them suitable starting points for development of novel classes of antibiotics. We have previously reported the increase in activity of AMPs upon addition of the Amino Terminal Copper and Nickel (ATCUN) Binding Unit. Herein we synthesized the membrane active peptide, Anoplin and two ATCUN-Anoplin derivatives and show that the increase in activity is indeed due to the ROS formation by the Cu(II)-ATCUN complex. We found that the ATCUN-Anoplin peptides were up to four times more potent compared to Anoplin alone against standard test bacteria. We studied membrane disruption, and cellular localization and found that addition of the ATCUN motif did not lead to a difference in these properties. When helical content was calculated, we observed that ATCUN-Anoplin had a lower helical composition. We found that ATCUN-Anoplin are able to oxidatively damage lipids in the bacterial membrane and that their activity trails the rate at which ROS is formed by the Cu(II)-ATCUN complexes alone. This study shows that addition of a metal binding tripeptide motif is a simple strategy to increase potency of AMPs by conferring a secondary action.
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http://dx.doi.org/10.1016/j.bbrc.2014.11.104DOI Listing
January 2015

A randomized controlled trial of a community-based nutrition education program for low-income parents.

J Nutr Educ Behav 2014 Mar-Apr;46(2):102-9. Epub 2013 Nov 20.

Department of Policy, Analysis, and Management, Cornell University, Ithaca, NY.

Objective: Assess effectiveness of the Expanded Food and Nutrition Education Program on nutrition behaviors post-education and longitudinally.

Design: Switching replications randomized experimental design. Participants randomly assigned to immediate education (IE) or delayed education (DE). Participants in IE received intervention the first 8 weeks, and those in DE the second 8 weeks, with no intervention during alternate periods. Data were collected in 3 repeated measures.

Participants: Parents (n = 168 randomized; n = 134 completed) of children in 2 Head Start and 6 low-income schools.

Intervention: Eight weekly workshops, based on Eating Right is Basic-Enhanced adapted to incorporate dialogue approach with experiential learning.

Main Outcome Measures: Ten-item self-reported behavior checklist on nutrition, food resource management, food safety, and food security; responses on a 5-point scale reporting frequency of behavior.

Analysis: Chi-square, analysis of variance, and multiple regression.

Results: Groups were demographically similar. Both groups reported improved behaviors pre- to post-education (P < .05). There was no significant difference between groups at Time 1 (T1) or DE control period (T1 vs T2). Changed IE behavior was retained T2 to T3. A multiple regression model of overall change, controlling for T1 score and educator, showed significant improvement (n = 134, β = 5.72, P < .001).

Conclusions And Implications: Positive outcomes were supported by this experimental study in a usual program context, with reported behavior changes retained at least 2 months.
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http://dx.doi.org/10.1016/j.jneb.2013.09.004DOI Listing
September 2014

Choices: anger and anger management in rehabilitative care.

Rehabil Nurs 2013 Mar-Apr;38(2):80-7

College of Nursing, University of Toledo, Toledo, OH 43614, USA.

Background And Purpose: Violent acts are on rise and rehabilitation providers as caregivers may encounter anger on a daily basis. The purpose of this article is to discuss anger and describe anger management strategies based on behavioral interventions grounded in Choice Theory.

Choice Theory: Applying choice theory to anger is the belief that people are internally, not externally motivated, and that outside events do not make people do anything. Thus, what drives people's anger behaviors are internally developed notions of what is important and satisfying for them.

Clinical Relevance And Conclusion: Anger becomes a choice along with its management. Choosing strategies to manage anger are key to reducing the potential for angry emotions to escalate to the point of aggressive and violent acts that threaten caregivers and clients safety. Anger-free environments promote mental/physical health and establish elements of safe living and working environments in a variety of rehabilitative care settings.
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http://dx.doi.org/10.1002/rnj.71DOI Listing
July 2013

Survival rates of mares and foals and postoperative complications and fertility of mares after cesarean section: 95 cases (1986-2000).

J Am Vet Med Assoc 2012 Oct;241(7):927-34

Rood and Riddle Equine Hospital, Lexington, KY 40511, USA.

Objective: To assess survival-to-discharge rates of mares and foals and postoperative complications and fertility in mares following cesarean section (C-section).

Design: Retrospective case series.

Animals: 95 mares.

Procedures: Medical and breeding records of mares that underwent C-section were reviewed; signalment, surgical technique, complications, survival-to-discharge rate, and pregnancy and foaling rates were recorded and evaluated. Foaling rates in the 3 years after C-section were compared with the cumulative foaling rate before C-section.

Results: C-section was performed because of dystocia (n = 71) or concurrent maternal disease (20) or was elective (4). Overall survival-to-discharge rate was 84% (80/95) for mares and 35% (28/80) for foals. Six of 15 mares that had partial fetotomies prior to C-section did not survive. Mares that had dystocia for < 90 minutes had the fewest complications. Cumulative foaling rate before C-section was 77% (394/509). Overall foaling rate for the 3 years after C-section was 52% (30/58) and 68% (13/19) when duration of dystocia was ≥ 90 minutes and < 90 minutes, respectively, and was 31 % (9/29) for mares ≥ 16 years old. Foaling rate was significantly lower for mares bred in the same year as C-section than for mares bred in later years.

Conclusions And Clinical Relevance: Breeding in the same year as C-section, dystocia for ≥ 90 minutes before C-section, and mare age ≥ 16 years were associated with poor foaling rates. Prognosis for delivery of a live foal in years following C-section was good if duration of dystocia was < 90 minutes and the mare was < 16 years old at the time of surgery.
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http://dx.doi.org/10.2460/javma.241.7.927DOI Listing
October 2012

Coaching efficacy and exploratory structural equation modeling: a substantive-methodological synergy.

J Sport Exerc Psychol 2011 Dec;33(6):779-806

Department of Educational and Psychological Studies, University of Miami, Coral Gables, FL, USA.

The purpose of this article was to provide a substantive-methodological synergy of potential importance to future research in sport and exercise psychology. The substantive focus was to improve the measurement of coaching efficacy by developing a revised version of the coaching efficacy scale (CES) for head coaches (N = 557) of youth sport teams (CES II-YST). The methodological focus was exploratory structural equation modeling (ESEM), a methodology that integrates the advantages of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) within the general structural equation model (SEM). The synergy was a demonstration of how ESEM (as compared with CFA) may be used, guided by content knowledge, to develop (or confirm) a measurement model for the CES II-YST. A single-group ESEM provided evidence for close model-data fit, while a single-group CFA fit significantly worse than the single-group ESEM and provided evidence for only approximate model-data fit. A multiple-group ESEM provided evidence for partial factorial invariance by coach's gender.
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http://dx.doi.org/10.1123/jsep.33.6.779DOI Listing
December 2011

Endoscopic evaluation of arytenoid function and epiglottic structure in Thoroughbred yearlings and association with racing performance at two to four years of age: 2,954 cases (1998-2001).

J Am Vet Med Assoc 2010 Mar;236(6):669-73

Rood and Riddle Equine Hospital, PO Box 12070, Lexington, KY 40580, USA.

OBJECTIVE-To determine the association between results of endoscopic evaluation of arytenoid function (AF) and epiglottic structure (ES) in Thoroughbred yearlings and racing performance at 2 to 4 years of age. DESIGN-Retrospective case series. ANIMALS-2,954 Thoroughbred yearlings. Procedures-Records of yearlings that had endoscopic evaluation of the larynx between 1998 and 2001 were obtained, and results were graded by use of standardized scales. A modified Havemeyer scale (grade I, II.1, II.2, III, or IV) was used to evaluate AF; ES was graded on a scale of 0 to IV. Records were annotated if the epiglottis was subjectively short or narrow. Racing performance data were obtained from an online database. RESULTS-Horses with grade II.2 AF had significantly less earnings at 4 years of age, compared with earnings of horses with AF grades < II.2. Grade III AF was associated with fewer starts and less earnings at 3 and 4 years of age. No horses met the criteria for grade IV AF. Horses with ES grades > II had less earnings at 2 and 4 years of age, compared with earnings of horses with ES grades < II. A short epiglottis was associated with less earnings at 2 and 3 years of age. CONCLUSIONS AND CLINICAL RELEVANCE-Analysis suggested that yearlings with grade III AF had a decrease in athletic potential. Yearlings with grade II.2 AF, an ES grade > II, or a short epiglottis typically had decreases in racing performance. These factors should be evaluated carefully when developing purchase recommendations.
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http://dx.doi.org/10.2460/javma.236.6.669DOI Listing
March 2010

Residual patterns of alkyl polyoxyethylene surfactant droplets after water evaporation.

J Agric Food Chem 2008 Jan 11;56(1):213-9. Epub 2007 Dec 11.

Albany State University Department of Natural Sciences, Albany GA 31705, USA.

Using a nonionic, alkyl polyoxyethylene surfactant (X-77) in aqueous solutions, sessile droplet spreading, pinning, evaporation, contraction, and post-evaporation deposits are characterized. X-77 is widely used in the agricultural field as a spreader/adherent, intended to optimize pathenogenic agent coverage. Using a single droplet size under monitored temperature conditions, we control humidity, substrate hydrophobicity, and surfactant concentration to mimic varying agricultural conditions. For hydrophilic surfaces, the droplet spreads, reaching and retaining a maximum, stationary size. At this stage, a ring accretion occurs at the maximum spread diameter. During the final stage, the water film retracts, resulting in deposition of small islands of surfactant residue inside the ring. At lower concentrations of surfactant, we discover ring formations that break-up into "ring islands" at late-stage evaporation, accompanied by a distribution of the smaller islands in the interior portion of the substrate contact area. These are promoted by higher relative humidity. At higher concentrations, only a solid ring of surfactant remains, post-evaporation. Increasing surfactant concentration tends to increase the mean of the interior island size and to broaden the overall island size distribution. On sufficiently hydrophobic surfaces, surfactant-laden droplets do not evidence pinning, ring formations, or post-evaporation interior islands. Interestingly, lower humidity increases spreading at higher surfactant concentrations. Such pattern formations of surfactant deposit are reported for the first time and are of significance in projecting how surfactants such as X-77 distribute pesticides or other chemicals on leaf surfaces.
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http://dx.doi.org/10.1021/jf072372yDOI Listing
January 2008

Sessile droplet de-pinning: new life for gravimetric data.

J Colloid Interface Sci 2007 Feb 24;306(1):187-91. Epub 2006 Oct 24.

Department of Natural Sciences, Albany State University, 504 College Drive, Albany, GA 31705, USA.

Using three different types of surfaces as exemplars, we report a gravimetric method as a viable tool for studying the de-pinning process. Namely, the de-pin time, tau(d) (the time required for a horizontal sessile droplet to de-pin at the triple phase line on a given substrate), is estimated without using a time consuming and expensive video imaging system. This is made possible by deciphering the non-linear portion of mass vs time data of an evaporating sessile droplet. Typical gravimetric glass-substrate evaporative mass loss vs time data has two regimes: a long, linear regime followed by a short, non-linear regime. Traditionally, researchers extract only the evaporation rate of a droplet from the linear regime but discard (by truncating the data) or ignore (thus deriving no information from) the non-linear regime. The origin of the linear to non-linear transition, found almost universally in gravimetric data, persists unremarked upon. By constructing three very different types of surfaces and comparing gravimetric data with video imaging data taken simultaneously, we report the transition is correlated to the onset of the de-pinning event in each case. This realization enables us to measure the de-pin time, tau(d), with gravimetric data only; i.e., without the video system, gathering more information from gravimetric data than previously considered. The method has application in estimating the de-pin time of a droplet deposited on a substrate that yields poor top-view contrast for videography, such as a water droplets on silicon wafers or glass substrates. Finally, gravimetric data is more accurate for evaporation modeling when substrate/droplet interaction areas are not circular.
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http://dx.doi.org/10.1016/j.jcis.2006.10.041DOI Listing
February 2007

Lead-free primer residues: a qualitative characterization of Winchester WinClean, Remington/UMC LeadLess, Federal BallistiClean, and Speer Lawman CleanFire handgun ammunition.

J Forensic Sci 2006 May;51(3):509-19

Department of Criminal Justice and Forensic Science, Albany State University, Albany, GA 31705, USA.

The elemental composition and postfiring residues of several "lead-free" or "nontoxic" centerfire handgun ammunition types currently available to the general public were examined. Offerings from Winchester, Remington/UMC, Federal and Speer were obtained from retail sources in both .45 ACP and 9 mm when possible. A total of 112 postfiring residue samples (SEM pins) were collected at varying distances from the muzzle, at two distances from target and from the shooter's hands. An additional 20 samples were collected by direct ignition of primers. Qualitative determinations were carried out using scanning electron microscopy (SEM)/electron dispersive spectrometry (EDS) analysis. All types tested contained aluminum (Al), silicon (Si), copper (Cu), and zinc (Zn). Most contain traces of sulfur and calcium. Winchester WinClean and Remington LeadLess contained potassium as the principle ingredient. Federal BallistClean contained barium, while Speer Lawman CleanFire contained strontium. In the main, these compared favorably with manufacturers' MSDS publications and patents granted. The characterizations undertaken here will be of use to the forensic electron microscopist as these formulations gain popularity.
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http://dx.doi.org/10.1111/j.1556-4029.2006.00107.xDOI Listing
May 2006
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