Publications by authors named "Timothy Ward"

81 Publications

Coordination and Solvation in Gas-Phase Ag(CH) Complexes Studied with Selected-Ion Infrared Spectroscopy.

J Phys Chem A 2020 Oct 4;124(41):8562-8573. Epub 2020 Oct 4.

Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.

Silver-acetylene cation complexes of the form Ag(CH) ( = 1-9) were produced via laser ablation in a supersonic expansion of acetylene/argon. The ions were mass selected and studied via infrared laser photodissociation spectroscopy in the C-H stretching region (3000-3500 cm). Fragmentation patterns indicate that four ligands are strongly coordinated to the metal cation. Density functional theory calculations were performed in support of the experimental data. Together, infrared spectroscopy and theory provide insight into the structure and bonding of these complexes. The Ag(CH) ( = 1-4) species are shown to be η-bonded, cation-π complexes with red-shifted C-H stretches on the acetylene ligands. Unlike Cu(CH) and Au(CH) complexes, which have a maximum coordination of three, silver cation is tetrahedrally coordinated to four acetylene ligands. Larger complexes ( = 5-9) are formed by solvation of the Ag(CH) core with acetylene. Similar to Cu(CH) and Au(CH) complexes, acetylene solvation leads to new and interesting infrared band patterns that are quite distinctive from those of the smaller complexes.
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http://dx.doi.org/10.1021/acs.jpca.0c08081DOI Listing
October 2020

Utilization and Appropriateness of Transthoracic Echocardiography in Response to the COVID-19 Pandemic.

J Am Soc Echocardiogr 2020 Jun 10;33(6):690-691. Epub 2020 Apr 10.

Department of Medicine, University of Chicago Medicine, Chicago, Illinois.

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http://dx.doi.org/10.1016/j.echo.2020.04.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146676PMC
June 2020

Infrared Spectroscopy of Zn(Acetylene) Complexes: Ligand Activation and Nascent Polymerization.

J Phys Chem A 2020 Jun 1;124(23):4764-4776. Epub 2020 Jun 1.

Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.

Zinc-acetylene ion-molecule complexes were produced by laser vaporization in a supersonic expansion. These complexes were mass selected and studied with infrared laser photodissociation spectroscopy complemented by computational chemistry. The combined approach of infrared spectroscopy and theory provides information on the structures and bonding of these complexes, as well as evidence for intracluster reactions. Fragmentation patterns demonstrate that the coordination number of strongly bonded ligands is three. Infrared spectra compared to those predicted by theory allow identification of different isomers at each cluster size. The coordination in these complexes varies between η and η metal-acetylene connections. Structures based on η bonding form a symmetric configuration for the = 3 complex. This unreactive core ion forms larger clusters with only weakly bonded acetylene in solvation structures. Structures based on three η-bonded acetylenes form a near- core ion which is the doorway configuration for subsequent reactions. Electron transfer to the next (fourth) acetylene produces a metal-carbon bond and a trans-bent metal-vinyl structure with a terminal radical site. This radical site attaches a fifth acetylene to produce a vinyl-dimer structure. Evidence for continued reactions in the larger clusters is obscured by solvating acetylenes with more intense IR bands. The asymmetric coordination of zinc cations and the critical configuration with three-fold coordination that leads to reactivity are new features of intracluster metal-molecular reactions.
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http://dx.doi.org/10.1021/acs.jpca.0c03358DOI Listing
June 2020

Intermediate-term annualized curve progression of adolescent idiopathic scoliosis curves measuring 40° or greater.

Spine Deform 2020 08 24;8(4):629-636. Epub 2020 Feb 24.

Pediatric Orthopaedic Division, Children's Hospital of Pittsburgh, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.

Study Design: Prospective cohort study.

Objectives: The objective of this study was to examine intermediate-term progression for a large series of patients with adolescent idiopathic scoliosis (AIS) with curves 40° or greater.

Background: Curve progression in AIS has been well documented for smaller curves in adolescence up to skeletal maturity; however, the data on curve progression past 40° or into adulthood are limited. With many surgeons recommending surgical correction when patients reach this threshold, it is important to understand the radiographic progression of curves into adulthood.

Methods: A database of all patients seen by a single surgeon from 1984 through 2018 with AIS curves progressing to at least 40° entered prospectively was utilized for this study. This included a total of 738 patients. Curve progression was analyzed overall and stratified by length of follow-up, curve location, and Risser stage at the time of presentation among other variables. Curve magnitude and Risser stage designations in this study were validated by performing a separate inter- and intrarater agreement study using four independent reviewers reading 50 patients' Cobb angle and Risser stage blinded in triplicate to examine the reliability of the study measurements.

Results: Annualized curve progression (ACP) averaged 6.3 ± 10.4°. ACP varied with length of follow-up: patients with up to 1 year of follow-up had an average ACP of 11.5 ± 17.0°, while those with 1-2 years had 8.2 ± 8.8°, and 2-5 years had 3.7 ± 4.1°, tapering off further from there. Risser stage 0 or 1 was associated with the highest ACP as compared to Risser stage 2-3 or 4-5. Intraclass correlation (ICC) values for Cobb angle measurement and Risser stage designations from four raters measuring 50 patients' measures, blinded and in triplicate, were all > 0.80, signifying a high degree of reliability within and between readers.

Conclusions: Annualized curve progression for 40° and greater curves was not linear over time; it was greatest immediately after a curve reaches 40° and tapered off over the next decade. Immature Risser stage at presentation was strongly associated with increasing ACP at all time frames.

Level Of Evidence: Prognostic Level I.
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http://dx.doi.org/10.1007/s43390-020-00088-3DOI Listing
August 2020

Microsolvation in V(HO) Clusters Studied with Selected-Ion Infrared Spectroscopy.

J Phys Chem A 2020 Feb 31;124(6):1093-1103. Epub 2020 Jan 31.

Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States.

Gas-phase ion-molecule clusters of the form V(HO) ( = 1-30) are produced by laser vaporization in a supersonic expansion. These ions are analyzed and mass-selected with a time-of-flight mass spectrometer and investigated with infrared laser photodissociation spectroscopy. The small clusters ( ≤ 7) are studied with argon tagging, while the larger clusters are studied via the elimination of water molecules. The vibrational spectra for the small clusters include only free O-H stretching vibrations, while larger clusters exhibit redshifted hydrogen bonding vibrations. The spectral patterns reveal that the coordination around V ions is completed with four water molecules. A symmetric square-planar structure forms for the = 4 ion, and this becomes the core ion in larger structures. Clusters up to = 8 have mostly two-dimensional structures, but hydrogen bonding networks evolve to three-dimensional structures in larger clusters. The free O-H vibration of acceptor-acceptor-donor (AAD)-coordinated surface molecules converges to a frequency near that of bulk water by the cluster size of = 30. However, the splitting of this vibration for AAD- versus AD-coordinated molecules is still different compared to other singly charged or doubly charged cation-water clusters. This indicates that cation identity and charge-site location in the cluster can produce discernable spectral differences for clusters in this size range.
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http://dx.doi.org/10.1021/acs.jpca.9b11275DOI Listing
February 2020

Cyclotrimerization of Acetylene in Gas Phase V(CH) Complexes: Detection of Intermediates and Products with Infrared Spectroscopy.

J Phys Chem A 2019 Aug 25;123(31):6733-6743. Epub 2019 Jul 25.

Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States.

Infrared laser spectroscopy and mass spectrometry were used to determine the structures of intermediates and products in the single-atom-catalyzed trimerization of acetylene to form benzene. Complexes of the form V(CH) were produced in the gas phase via laser ablation in a pulsed-nozzle source, size-selected with a mass spectrometer, and studied with infrared laser photodissociation spectroscopy. Density functional theory calculations were performed in support of the experiments. Single- and double-acetylene complexes form V(CH) metallacycle structures. Three-acetylene complexes exhibit a surprising dependence on the acetylene concentration, forming V(CH) and (CH)V(CH) tri- and dimetallacycle ion structures at low concentrations and eventually V(benzene) at higher concentrations. These observations reveal intermediates along the reaction path of acetylene cyclotrimerization to benzene.
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http://dx.doi.org/10.1021/acs.jpca.9b04962DOI Listing
August 2019

Spinal Instrumentation in Growing Children Retards the Natural Development of Pelvic Incidence.

J Pediatr Orthop 2019 Mar;39(3):141-145

Department of Orthopaedics and Traumatology, Hacettepe University School of Medicine, Ankara.

Background: Pelvic incidence increases gradually throughout growth until skeletal maturity. Growing rod instrumentation has been suggested to have a stabilizing effect on the development of the normal sagittal spinal alignment. The purpose of this study is to determine the effect of fixed sagittal plane caused by dual growing rod instrumentation on the natural progression of sagittal spinopelvic parameters in children with idiopathic or idiopathic-like early onset scoliosis.

Methods: Hospital records of children with growing rod instrumentation from 4 separate institutions were reviewed retrospectively. Inclusion criteria were idiopathic or idiopathic-like early onset scoliosis, treatment with dual growing rods with lower instrumented vertebra L4 or upper and more than 2 years of follow-up. Instrumentation levels, magnitudes of major curve, thoracic kyphosis (T2-T12), lumbar lordosis (L1-S1) and pelvic incidence were recorded from preoperative and postoperative standing whole-spine radiographs. Estimated pelvic incidence was also calculated for each patient as if their spines had not been instrumented using the previous normative data.

Results: A total of 37 patients satisfied the inclusion criteria. Average age at initial surgery was 7.4±1.8 years (range, 4 to 12 y). Mean follow-up time was 71±26 months (range, 27 to 120 mo). Mean preoperative Cobb angle of 59±13.5 (range, 30 to 86) degrees was reduced to 35.1±17.5 (range, 11 to 78) degrees at the last follow-up. Mean preoperative T2-T12 kyphosis angle was 46.2±14.9 degrees (range, 22 to 84 degrees). At the latest follow-up, it was 44.8±16.2 degrees (range, 11 to 84 degrees) (P=0.93). Mean L1-S1 lordosis angle was 50.5±10.7 degrees (range, 30 to 72 degrees) preoperatively. At the latest follow-up, mean L1-S1 lordosis angle was 48.8±12.7 degrees (range, 26 to 74 degrees) (P=0.29). Mean preoperative pelvic incidence was 45.7±7.9 degrees (range, 30 to 68 degrees). At the latest follow-up, it was 46.7±8.4 degrees (range, 34 to 72 degrees) (P=0.303). The estimated average pelvic incidence was 49.5 degrees (P=0.012).

Conclusions: Previously reported developmental changes of the sagittal spinal parameters were not observed in children who underwent posterior spinal instrumentation. Our findings suggest that spinal instrumentation impedes the natural development of the sagittal spinal profile.

Level Of Evidence: Level IV-this is a retrospective case-series.
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http://dx.doi.org/10.1097/BPO.0000000000000882DOI Listing
March 2019

Photodegradation of clothianidin and thiamethoxam in agricultural soils.

Environ Sci Pollut Res Int 2018 Nov 7;25(31):31318-31325. Epub 2018 Sep 7.

Department of Chemistry & Biochemistry, Millsaps College, 1701 N State Street, Jackson, MS, 39202, USA.

Presented in this paper is a study on the photodegradation of two widely used neonicotinoid insecticides clothianidin and thiamethoxam in three soils and in solid phase. The effects of light with differing wavelengths were examined using the natural sunlight and single ultraviolet A (UVA) and ultraviolet B (UVB) light sources. The results indicated that UVB played a key role in the photodegradation of clothianidin and thiamethoxam while the effects of visible and UVA lights were negligible. The degradations of clothianidin and thiamethoxam under all the light sources followed the first-order kinetics, and the half-lives of clothianidin and thiamethoxam in the three soils under the sunlight ranged from 97 to 112 h and 88 to 103 h, respectively. When clothianidin and thiamethoxam were directly exposed to the sunlight without soil, the degradation rates were remarkably higher with half-lives being 13 and 10 h, respectively. Therefore, the insecticides fallen on the surface of soils would be degraded under sunlight much faster than those that enter the soils. The examination of the degradation products revealed four compounds from the photodegradation of clothianidin and three from thiamethoxam, and clothianidin was one of the photodegradation products of thiamethoxam.
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http://dx.doi.org/10.1007/s11356-018-3121-9DOI Listing
November 2018

Effects of cupric chloride on coagulation in human plasma: role of fibrinogen.

J Thromb Thrombolysis 2018 Oct;46(3):359-364

Department of Anesthesiology, The University of Arizona College of Medicine, P.O. Box 245114, 1501 North Campbell Avenue, Tucson, AZ, 85724-5114, USA.

Introduction: Copper poisoning is associated with severe multiorgan injury and potentially death if chelation therapy is not administered. Of interest, while important gastrointestinal and urinary tract hemorrhage is associated with copper poisoning, very little is known concerning the nature of copper induced coagulopathy.

Methods: Using thrombelastography, we assessed changes in coagulation kinetics in human plasma following exposure to copper concentrations encountered during poisoning.

Results: While time to commence coagulation was not compromised, both velocity of thrombus growth and final strength were diminished. This result was duplicated with one concentration of copper in factor XIII deficient plasma. This pattern of coagulation kinetic response was interpreted as copper mediated fibrinogen dysfunction, perhaps via oxidation of key fibrinogen disulfide bridges. Lastly, experiments wherein glutathione was added implicated copper generated radical oxygen species as one of the mechanisms responsible for compromised coagulation kinetics.

Conclusions: While chelation therapy is the key to survival following copper poisoning, perhaps this and future investigations of how copper affects coagulation may provide insight into effective supportive therapy for patients with active bleeding.
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http://dx.doi.org/10.1007/s11239-018-1704-4DOI Listing
October 2018

Amino acid racemization and its relation to geochronology and archaeometry.

J Sep Sci 2018 Mar;41(6):1489-1506

Department of Chemistry and Biochemistry, Keck Center for Instrumental and Biochemical Comparative Archaeology, Millsaps College, Jackson, MS, USA.

Amino acid racemization, used as a method of relative and quantitative dating of fossils, evaluates the degree of postmortem conversion of l to d amino acid enantiomers. While extensively utilized, this method has garnered confusion due to controversial age estimates for human fossils in North America in the 1970s. This paper explains the age controversy and aftermath, current chromatographic methods used in research, mathematical calibration models, and a short synopsis of other dating techniques in geochronology and archaeometry.
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http://dx.doi.org/10.1002/jssc.201701506DOI Listing
March 2018

Potent Pyrimidine and Pyrrolopyrimidine Inhibitors of Testis-Specific Serine/Threonine Kinase 2 (TSSK2).

ChemMedChem 2017 11 20;12(22):1857-1865. Epub 2017 Oct 20.

Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, 55414, USA.

Testis-specific serine/threonine kinase 2 (TSSK2) is an important target for reversible male contraception. A high-throughput screen of ≈17 000 compounds using a mobility shift assay identified two potent series of inhibitors having a pyrrolopyrimidine or pyrimidine core. The pyrrolopyrimidine 10 (IC 22 nm; GSK2163632A) and the pyrimidine 17 (IC 31 nm; ALK inhibitor 1) are the most potent TSSK2 inhibitors in these series, which contain the first sub-100 nanomolar inhibitors of any TSSK isoform reported, except for the broad kinase inhibitor staurosporine. The novel, potent pyrimidine TSSK2 inhibitor compound 19 (IC 66 nm; 2-[[5-chloro-2-[2-methoxy-4-(1-methylpiperidin-4-yl)anilino]pyrimidin-4-yl]amino]-N-methylbenzenesulfonamide) lacks the potential for metabolic activation. Compound 19 had a potency rank order of TSSK1>TSSK2>TSSK3>TSSK6, indicating that potent dual inhibitors of TSSK1/2 can be identified, which may be required for a complete contraceptive effect. The future availability of a TSSK2 crystal structure will facilitate structure-based discovery of selective TSSK inhibitors from these pyrrolopyrimidine and pyrimidine scaffolds.
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http://dx.doi.org/10.1002/cmdc.201700503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962959PMC
November 2017

SRS-22r Scores in Nonoperated Adolescent Idiopathic Scoliosis Patients With Curves Greater Than Forty Degrees.

Spine (Phila Pa 1976) 2017 Aug;42(16):1233-1240

Pediatric Orthopaedic Division, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA.

Study Design: Case control comparative series.

Objective: Describe surgical range adolescent idiopathic scoliosis (AIS) patients electing to forgo surgery and compare health-related quality-of-life outcomes to a similar cohort of operated AIS patients by the same single surgeon.

Summary Of Background Data: No data have been published either documenting SRS-22r scores of nonoperated patients with curves ≥40° or comparing these scores to a demographically similar operated cohort.

Methods: Individuals with curves ≥40°, age ≥18 years, and electing to forgo surgery were identified. All patients completed an SRS-22r questionnaire. This nonoperated cohort's SRS-22r scores were compared to those of a large demographically similar cohort operated by the same surgeon. Group differences between the SRS-22r scores were evaluated by comparing these to published Minimal Clinically Important Differences (MCID) for the SRS-22r.

Results: One hundred ninety subjects with nonoperated curves were compared to 166 individuals who underwent surgery. The nonoperated cohort averaged 23.5 years of age, averaged 7.7 years since curve reached 40°, and had an average 50° Cobb angle at last follow-up. No statistical significant differences were found between the groups on the Pain, Function, or Mental Health domains of the SRS-22r. Statistically significant differences in favor of the operative cohort were found for self-image, satisfaction, and total score. The observed group differences did not meet the established thresholds for minimal clinically important differences in any of the domain scores, the average total score, or raw scores.

Conclusion: There are no meaningful clinically significant differences in SRS-22r scores at average 8-year follow-up between AIS patients with curves ≥40° treated with or without surgery. These data in conjunction with an absence of long-term evidence of serious medical consequences with nonsurgical management of curves ≥40° should encourage surgeons to reevaluate the benefits of routine surgical care.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000002004DOI Listing
August 2017

BET Bromodomain Inhibitors with One-Step Synthesis Discovered from Virtual Screen.

J Med Chem 2017 06 7;60(12):4805-4817. Epub 2017 Jun 7.

Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.

Chemical inhibition of epigenetic regulatory proteins BrdT and Brd4 is emerging as a promising therapeutic strategy in contraception, cancer, and heart disease. We report an easily synthesized dihydropyridopyrimidine pan-BET inhibitor scaffold, which was uncovered via a virtual screen followed by testing in a fluorescence anisotropy assay. Dihydropyridopyimidine 3 was subjected to further characterization and is highly selective for the BET family of bromodomains. Structure-activity relationship data and ligand deconstruction highlight the importance of the substitution of the uracil moiety for potency and selectivity. Compound 3 was also cocrystallized with Brd4 for determining the ligand binding pose and rationalizing subsequent structure-activity data. An additional series of dihydropyridopyrimidines was synthesized to exploit the proximity of a channel near the ZA loop of Brd4, leading to compounds with submicromolar affinity and cellular target engagement. Given these findings, novel and easily synthesized inhibitors are being introduced to the growing field of bromodomain inhibitor development.
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http://dx.doi.org/10.1021/acs.jmedchem.6b01336DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5558211PMC
June 2017

Outcomes of Pediatric Fractures Managed With Closed Reduction by Orthopaedic Residents in the Emergency Department.

J Pediatr Orthop 2017 Jun;37(4):e243-e245

*Children's Hospital of PittsburghPittsburgh, PA †Kids Specialty Center, Lafayette, LA.

Background: Closed reduction of pediatric fractures is commonly performed by orthopaedic residents using conscious sedation in the emergency department (ED). The purpose of this study was to determine the rate of satisfactory reductions as performed by residents, and to determine the outcomes of these procedures.

Methods: A retrospective review was performed of all fractures that underwent closed reduction under conscious sedation in the ED of a level 1 pediatric trauma center between January 1, 2010 and November 30, 2014. Initial and subsequent radiographs were reviewed and a determination was made as to whether the initial reduction was satisfactory, based on predetermined criteria for angulation and displacement. If a second reduction attempt in the operating room was necessary, this was noted. Chart notes were reviewed until a documented endpoint was reached, such as uneventful healing, malunion, nonunion, or growth arrest.

Results: A total of 838 subjects were identified. The upper extremity was involved in 85% of the fractures. Of the initial 838 fracture reductions performed, 39 (4.7%) were unsatisfactory. Residents on their first pediatric orthopaedic rotation had a higher unsatisfactory reduction rate compared with more experienced residents (7.0% vs. 3.4%, P=0.01). A second reduction was performed for 94 of 749 (12.6%) fractures. Of these, 35 (37.2%) required an open procedure to accomplish a satisfactory reduction. Fractures with initially satisfactory reductions were significantly less likely to require a second reduction attempt than those with initially unsatisfactory reductions (9.2% vs. 80.0%, P<0.01). The likelihood of a satisfactory reduction was significantly higher in the upper extremity than in the lower extremity. Overall, the vast majority (99.2%) of fractures had a satisfactory final outcome.

Conclusions: Most attempts at closed reduction of pediatric fractures in the ED by orthopaedic residents are successful, and the likelihood of a satisfactory reduction was associated with increased levels of resident experience. Fractures with an initially successful reduction were far less likely to require remanipulation.

Level Of Evidence: Level IV-this is a therapeutic case series.
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http://dx.doi.org/10.1097/BPO.0000000000000937DOI Listing
June 2017

Is There Value in Having Radiology Provide a Second Reading in Pediatric Orthopaedic Clinic?

J Pediatr Orthop 2017 Jun;37(4):e292-e295

*Children's Hospital of Pittsburgh †University of Pittsburgh School of Public Health, Pittsburgh, PA.

Background: The Joint Commission on Accreditation of Healthcare Organizations specifically mandates the dual interpretation of musculoskeletal radiographs by a radiologist in addition to the orthopaedist in all hospital-based orthopaedic clinics. Previous studies have questioned the utility of this practice. The purpose of this study was to further investigate the clinical significance of having the radiologist provide a second interpretation in a hospital-based pediatric orthopaedic clinic.

Methods: A retrospective review was performed of all patients who had plain radiographs obtained in the pediatric orthopaedic clinic at an academic children's hospital over a 4-month period. For each radiographic series, the orthopaedist's note and the radiology interpretation were reviewed and a determination was made of whether the radiology read provided new clinically useful information and/or a new diagnosis, whether it recommended further imaging, or if it missed a diagnosis that was reflected in the orthopaedist's note. The hospital charges associated with the radiology read for each study were also quantified.

Results: The charts of 1570 consecutive clinic patients who were seen in the pediatric orthopaedic clinic from January to April, 2012 were reviewed. There were 2509 radiographic studies performed, of which 2264 had both a documented orthopaedist's note and radiologist's read. The radiologist's interpretation added new, clinically important information in 1.0% (23/2264) of these studies. In 1.7% (38/2264) of the studies, it was determined that the radiologist missed the diagnosis or clinically important information that could affect treatment. The total amount of the professional fees charged for the radiologists' interpretations was $87,362. On average, the hospital charges for each occurrence in which the radiologist's read provided an additional diagnosis or clinically important information beyond the orthopaedist's note were $3798.

Conclusions: The results of this study suggest that eliminating the requirement to have the radiologist interpret radiographs in the pediatric orthopaedic clinic would have few clinical consequences.

Level Of Evidence: Level III-This is a diagnostic retrospective cohort study.
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http://dx.doi.org/10.1097/BPO.0000000000000917DOI Listing
June 2017

Does a Weekly Didactic Conference Improve Resident Performance on the Pediatric Domain of the Orthopaedic In-Training Examination?

J Pediatr Orthop 2017 Mar;37(2):149-153

*Shriners Hospitals for Children, Philadelphia †Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh §Department of Orthopaedic Surgery, UPMC Hamot, Erie, PA ‡Department of Orthopaedic Surgery, Cooper Medical School of Rowan University, Camden, NJ.

Background: Performance on the Orthopaedic In-training Examination (OITE) has been correlated with performance on the written portion of the American Board of Orthopaedic Surgery examination. Herein we sought to discover whether adding a regular pediatric didactic lecture improved residents' performance on the OITE's pediatric domain.

Methods: In 2012, a didactic lecture series was started in the University of Pittsburgh Medical Center (UPMC) Hamot Orthopaedic Residency Program (Hamot). This includes all topics in pediatric orthopaedic surgery and has teaching faculty present, and occurs weekly with all residents attending. A neighboring program [UMPC Pittsburgh (Pitt)] shares in these conferences, but only during their pediatric rotation. We sought to determine the effectiveness of the conference by comparing the historic scores from each program on the pediatric domain of the OITE examination to scores after the institution of the conference, and by comparing the 2 programs' scores.

Results: Both programs demonstrated improvement in OITE scores. In 2008, the mean examination score was 19.6±4.3 (11.0 to 30.0), and the mean percentile was 57.7±12.6 (32.0 to 88.0); in 2014, the mean examination score was 23.5±4.2 (14.0 to 33.0) and the mean percentile was 67.1±12.1 (40.0 to 94.0). OITE scores and percentiles improved with post graduate year (P<0.0001). Compared with the preconference years, Hamot residents answered 3.99 more questions correctly (P<0.0001) and Pitt residents answered 2.93 more questions correctly (P<0.0001). Before the conference, site was not a predictor of OITE score (P=0.06) or percentile (P=0.08); there was no significant difference found between the mean scores per program. However, in the postconference years, site did predict OITE scores. Controlling for year in training, Hamot residents scored higher on the OITE (2.3 points higher, P=0.003) and had higher percentiles (0.07 higher, P=0.004) than Pitt residents during the postconference years.

Conclusions: This study suggests that adding a didactic pediatric lecture improved residents' scores on the OITE and indirectly suggests that more frequent attendance is associated with better scores.

Level Of Evidence: Level III-retrospective case-control study.
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http://dx.doi.org/10.1097/BPO.0000000000000726DOI Listing
March 2017

Ritual drinks in the pre-Hispanic US Southwest and Mexican Northwest.

Proc Natl Acad Sci U S A 2015 Sep 8;112(37):11436-42. Epub 2015 Sep 8.

Cultural Resource Management Program, Gila River Indian Community, Sacaton, AZ 85147.

Chemical analyses of organic residues in fragments of pottery from 18 sites in the US Southwest and Mexican Northwest reveal combinations of methylxanthines (caffeine, theobromine, and theophylline) indicative of stimulant drinks, probably concocted using either cacao or holly leaves and twigs. The results cover a time period from around A.D. 750-1400, and a spatial distribution from southern Colorado to northern Chihuahua. As with populations located throughout much of North and South America, groups in the US Southwest and Mexican Northwest likely consumed stimulant drinks in communal, ritual gatherings. The results have implications for economic and social relations among North American populations.
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http://dx.doi.org/10.1073/pnas.1511799112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4577151PMC
September 2015

Survival, Reproduction and Growth of the Marine Amphipod, Leptocheirus plumulosus, Following Laboratory Exposure to Copper-Spiked Sediment.

Bull Environ Contam Toxicol 2015 Oct 14;95(4):434-40. Epub 2015 Sep 14.

Environmental Research and Information Analysts, Dubuque, IA, 52001, USA.

Leptocheirus plumulosus was exposed for 28 days to Cu-spiked sediment at mean concentrations ranging from 44.4 to 605 mg Cu/kg dry sediment in a sediment/water test system designed to simulate natural conditions. The NOEC (no observed effect concentration)-LOEC (lowest observed effect concentration) range for the most sensitive endpoint of growth was 199-414 mg Cu/kg sediment. An IC50 for reproduction was estimated at 187 mg Cu/kg sediment. Mean Cu concentrations in pore water (PW) where significant effects were observed were 25.8 and 59.0 µg/L, while their respective concentrations in overlying water (OW) were 22.1 and 28.0 µg Cu/L. Copper concentrations were ≤19.1 and <16.6 µg/L in PW and OW, respectively, at lower exposures where effects were not evident. Concentrations of Cu in marine sediment lower than sediment quality guidelines based on geochemical factors of acid volatile sulfide, organic carbon content (f OC), and sediment grain size (i.e., silt + clay) would appear not to result in adverse effects toward L. plumulosus.
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http://dx.doi.org/10.1007/s00128-015-1638-xDOI Listing
October 2015

Cas9-Guide RNA Directed Genome Editing in Soybean.

Plant Physiol 2015 Oct 20;169(2):960-70. Epub 2015 Aug 20.

DuPont Pioneer Agricultural Biotechnology, Wilmington, Delaware 19803.

Recently discovered bacteria and archaea adaptive immune system consisting of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) endonuclease has been explored in targeted genome editing in different species. Streptococcus pyogenes Cas9-guide RNA (gRNA) was successfully applied to generate targeted mutagenesis, gene integration, and gene editing in soybean (Glycine max). Two genomic sites, DD20 and DD43 on chromosome 4, were mutagenized with frequencies of 59% and 76%, respectively. Sequencing randomly selected transgenic events confirmed that the genome modifications were specific to the Cas9-gRNA cleavage sites and consisted of small deletions or insertions. Targeted gene integrations through homology-directed recombination were detected by border-specific polymerase chain reaction analysis for both sites at callus stage, and one DD43 homology-directed recombination event was transmitted to T1 generation. T1 progenies of the integration event segregated according to Mendelian laws and clean homozygous T1 plants with the donor gene precisely inserted at the DD43 target site were obtained. The Cas9-gRNA system was also successfully applied to make a directed P178S mutation of acetolactate synthase1 gene through in planta gene editing.
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http://dx.doi.org/10.1104/pp.15.00783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4587461PMC
October 2015

Survival and Growth of the Marine Polychaete, Neanthes arenaceodentata, Following Laboratory Exposure to Copper-Spiked Sediment.

Bull Environ Contam Toxicol 2015 Oct 27;95(4):428-33. Epub 2015 Jun 27.

Environmental Research and Information Analysts, Dubuque, IA, 52001, USA.

Juvenile marine polychaetes, Neanthes arenaceodentata, were exposed for 28 days to copper (Cu)-spiked sediment at six concentrations ranging from 48.3 to 2380 mg Cu/kg dry sediment, plus control. Survival was reduced (p ≤ 0.05) at concentrations ≥1190 mg Cu/kg. Growth was inhibited at Cu concentrations ≥506 mg Cu/kg. Dose-response relationships yielded LC10 and LC50 estimates of 514 and 1230 mg Cu/kg, respectively. The growth effect EC50 estimate was 409 mg Cu/kg. Ranges for the no observable effect concentration and lowest observable effect concentration were 506-1190 mg Cu/kg for survival, and 230-506 mg Cu/kg for growth. Pore water concentrations of Cu were 38.7-65.8 µg Cu/L in exposures where toxic effects were observed, compared to a range of 15.1-22.4 µg Cu/L in exposures where significant effects were not evident. The results of the study were compared with empirical and mechanistic sediment quality guidelines for the protection of benthic organisms.
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http://dx.doi.org/10.1007/s00128-015-1582-9DOI Listing
October 2015

Cation-π and CH-π Interactions in the Coordination and Solvation of Cu(+)(acetylene)n Complexes.

J Phys Chem A 2015 Jun 15;119(22):5658-67. Epub 2015 May 15.

‡Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.

Copper-acetylene cation complexes of the form Cu(C2H2)n(+) (n = 1-8) are produced by laser ablation in a supersonic expansion of acetylene/argon. The ions are mass selected and studied via infrared laser photodissociation spectroscopy in the C-H stretching region (3000-3500 cm(-1)). The structure and bonding of these complexes are investigated through the number of infrared active bands, their relative intensities and their frequency positions. Density functional theory calculations are carried out in support of the experimental data. The combined data show that cation-π complexes are formed for the n = 1-3 species, resulting in red-shifted C-H stretches on the acetylene ligands. The coordination of the copper cation is completed with three acetylene ligands, forming a "propeller" structure with D3 symmetry. Surprisingly, complexes with even greater numbers of acetylenes than this (4-6) have distinctive infrared band patterns quite different from those of the smaller complexes. Experiment combined with theory establishes that there is a fascinating pattern of second-sphere solvation involving the binding of acetylenes in bifurcated CH-π binding sites at the apex of two core ligands. This binding motif leads to three equivalent sites for second-sphere ligands, which when filled form a highly symmetrical Cu(+)(C2H2)6 complex. Solvent binding in this complex induces a structural change to planarity in the core, producing an appealing "core-shell" structure with D(3h) symmetry.
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http://dx.doi.org/10.1021/acs.jpca.5b03360DOI Listing
June 2015

Exercise-induced Pediatric Lumbar Paravertebral Compartment Syndrome: A Case Report.

J Pediatr Orthop 2015 Sep;35(6):e49-51

Department of Orthopaedic Surgery, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA.

Acute compartment syndrome is described as an elevation of interstitial pressure in a closed fascial compartment that can lead to damage of the microvasculature with subsequent tissue necrosis. Although paravertebral compartment syndrome has been described there is no case of paravertebral compartment syndrome that has been described in the pediatric population. We report the case of a 17-year-old boy who presented at our institution with severe, acute-onset low back pain that started shortly after a rigorous 4-hour workout. He was diagnosed with acute lumbar paravertebral compartment syndrome and underwent emergent fasciotomy with 2 more debridements.
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http://dx.doi.org/10.1097/BPO.0000000000000478DOI Listing
September 2015

Hematoma block versus sedation for the reduction of distal radius fractures in children.

J Hand Surg Am 2015 Jan 11;40(1):57-61. Epub 2014 Oct 11.

Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA; Division of Pediatric Emergency Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA.

Purpose: To determine which mode of anesthesia, hematoma block (HB) or procedural sedation (PS), was preferable for distal radius fracture (DRF) reduction in children.

Methods: Fifty-two children (mean age, 12 y; range, 5-16 y) presenting with DRFs requiring reduction were prospectively enrolled and offered either PS or HB for anesthesia. Following reduction, families completed a satisfaction survey regarding mode of anesthesia and overall care (rated 0-10, with 10 being the best score) and an assessment of discomfort (rated 0-10, with 0 being no pain). Length of stay in the emergency department (ED) and complications related to procedure and method of anesthesia were recorded. Radiographic alignment was evaluated before and after reduction.

Results: Twenty-six patients underwent reduction with either PS or HB. Midazolam was used in addition to HB in 8 patients. One patient was converted from HB to PS due to inadequate block. There was no significant difference in prereduction and postreduction angulation between the groups, and reductions maintained satisfactory alignment. Overall satisfaction and satisfaction with anesthesia were excellent for both groups, with respective means of 9.5 and 9.5 for PS and 9.3 and 9.6 for HB. Patient discomfort was minimal in both groups, with a mean of 1.6 for PS and 2.2 for HB. Length of stay was significantly shorter for HB patients, with patients spending a mean of 2.2 hours less in the ED. Three patients required further intervention following initial reduction. One patient in each group required revision reduction, and 1 PS patient underwent closed reduction and pinning.

Conclusions: Use of HB for the reduction of pediatric DRFs provided radiographic alignment, patient satisfaction, and pain control comparable with that of PS, while significantly decreasing ED time and resources.
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http://dx.doi.org/10.1016/j.jhsa.2014.08.039DOI Listing
January 2015

Vertebral artery injuries in cervical spine surgery.

Spine J 2014 Aug 10;14(8):1520-5. Epub 2013 Oct 10.

Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Kaufmann Medical Building, 3471 Fifth Ave., Pittsburgh, PA 15213, USA.

Background Context: Vertebral artery injuries (VAIs) are rare but serious complications of cervical spine surgery, with the potential to cause catastrophic bleeding, permanent neurologic impairment, and even death. The present literature regarding incidence of this complication largely comprises a single surgeon or small multicenter case series.

Purpose: We sought to gather a large sample of high-volume surgeons to adequately characterize the incidence and risk factors for VAI, management strategies used, and patient outcomes after VAI.

Study Design: The study was constructed as a cross-sectional study comprising all cervical spine patients operated on by the members of the international Cervical Spine Research Society (CSRS).

Patient Sample: All patients who have undergone cervical spine surgery by a current member of CSRS as of the spring of 2012.

Outcome Measures: For each surgeon surveyed, we collected self-reported measures to include the number of cervical cases performed in the surgeon's career, the number of VAIs encountered, the stage of the case during which the injury occurred, the management strategies used, and the overall patient outcome after injury.

Methods: An anonymous 10-question web-based survey was distributed to the members of the CSRS. Statistical analysis was performed using Student t tests for numerical outcomes and chi-squared analysis for categorical variables.

Results: One hundred forty-one CSRS members (of 195 total, 72%) responded to the survey, accounting for a total of 163,324 cervical spine surgeries performed. The overall incidence of VAI was 0.07% (111/163,324). Posterior instrumentation of the upper cervical spine (32.4%), anterior corpectomy (23.4%), and posterior exposure of the cervical spine (11.7%) were the most common stages of the case to result in an injury to the vertebral artery. Discectomy (9%) and anterior exposure of the spine (7.2%) were also common time points for an arterial injury. One-fifth (22/111) of all VAI involved an anomalous course of the vertebral artery. The most common management of VAI was by direct tamponade. The outcomes of VAIs included no permanent sequelae in 90% of patients, permanent neurologic sequelae in 5.5%, and death in 4.5%. Surgeons at academic and private centers had nearly identical rates of VAIs. However, surgeons who had performed 300 or fewer cervical spine surgeries in their career had a VAI incidence of 0.33% compared with 0.06% in those with greater than 300 lifetime cases (p=.028).

Conclusions: The overall incidence of VAI during cervical spine surgery reported from this survey was 0.07%. Less experienced surgeons had a higher rate of VAI compared with their more experienced peers. The results of VAI are highly variable, resulting in no permanent harm most of the time; however, permanent neurologic injury or death occur in 10% of cases.
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http://dx.doi.org/10.1016/j.spinee.2013.09.016DOI Listing
August 2014

Somatosensory-evoked potential monitoring during instrumented scoliosis corrective procedures: validity revisited.

Spine J 2014 Aug 19;14(8):1572-80. Epub 2013 Oct 19.

Department of Neurological Surgery, University of Pittsburgh Medical Center Presbyterian, Suite B-400, 200 Lothrop St, Pittsburgh, PA 15213, USA.

Background: Intraoperative monitoring (IOM) using somatosensory-evoked potentials (SSEPs) plays an important role in reducing iatrogenic neurologic deficits during corrective pediatric idiopathic procedures for scoliosis. However, for unknown reasons, recent reports have cited that the sensitivity of SSEPs to detect neurologic deficits has decreased, in some to be less than 50%. This current trend, which is coincident with the addition of transcranial motor-evoked potentials, is surprising given that SSEPs are robust, reproducible responses that were previously shown to have sensitivity and specificity of >90%.

Purpose: Our primary aim was to assess whether SSEPs alone can detect impending neurologic deficits with similar sensitivity and specificity as originally reported. Our secondary aim was to estimate the potential predictive value of adding transcranial motor-evoked potentials to SSEP monitoring in idiopathic scoliosis procedures.

Design: This was a retrospective review to analyze the efficacy of SSEP monitoring in the group of pediatric instrumented scoliosis fusion cases.

Patient Sample: We retrospectively reviewed all consecutive cases of patients who underwent idiopathic scoliosis surgery between 1999 and 2009 at Children's Hospital of Pittsburgh. We identified 477 patients who had the surgery with SSEP monitoring alone. Exclusion criteria included any patients with neuromuscular disorders or unreliable SSEP monitoring. Patients who had incomplete neurophysiology data or incomplete postoperative records were also excluded.

Outcome Measures: Major outcomes measured were clinically significant postoperative sensory or motor deficits, as well as significant intraoperative SSEP changes.

Methods: Continuous interleaved upper- and lower-extremity SSEPs were obtained throughout the duration of all procedures. We considered a persistent 50% reduction in primary somatosensory cortical amplitude or a prolongation of response latency by >10% from baseline to be significant. Persistent changes represent significant deviation in SSEP amplitude or latency in more than two consecutive averaged trials. Patients were classified into one of four categories with respect to SSEP monitoring: true positive, false positive, true negative, and false negative. The sensitivity, specificity, positive predictive value, and negative predictive value were then calculated accordingly.

Results: Our review of 477 idiopathic scoliosis surgeries monitored using SSEPs alone revealed a new deficit rate of 0.63% with no cases of permanent injury. Sensitivity = 95.0%, specificity = 99.8%, positive predictive value = 95%, negative predictive value = 99.8%. Using evidence-based epidemiologic measures, we calculated that the number needed to treat was 1,587 patients for one intervention to be performed that would have been missed by SSEP monitoring alone. In addition, the number needed to harm, which represents the increase in false positives with the addition of transcranial electrical motor-evoked potentials, was 200.

Conclusion: SSEP monitoring alone during idiopathic scoliosis continues to be a highly reliable method for the detection and prevention of iatrogenic injury. Our results confirm the high sensitivity and specificity of SSEP monitoring alone published in earlier literature. As such, we suggest the continued use of SSEP alone in idiopathic scoliosis surgeries. At this time we do not believe there are sufficient data to support the addition of MEP monitoring, although more studies and revised criteria for the use of MEP may provide added value for its use in the future.
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http://dx.doi.org/10.1016/j.spinee.2013.09.035DOI Listing
August 2014

Converting Scoliosis Research Society-24 to Scoliosis Research Society-22r in a Surgical-Range, Medical/Interventional Adolescent Idiopathic Scoliosis Patient Cohort.

Spine Deform 2013 Mar 15;1(2):108-114. Epub 2013 Mar 15.

Department of Orthopaedics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh, Department of Orthopaedics, 4401 Penn Avenue, Fourth Floor, Pittsburgh, PA 15224, USA. Electronic address:

Study Design: Prospective questionnaire administration study.

Objectives: To assess the ability to translate total and domain scores from Scoliosis Research Society (SRS)-24 to SRS-22r in a surgical-range, medical/interventional adolescent idiopathic scoliosis (AIS) patient population.

Summary Of Background Data: Conversion of SRS-24 to SRS-22r is demonstrated in an operative cohort of patients with AIS, but not in a medical/interventional patient population.

Methods: We simultaneously administered SRS-24 and SRS-22r questionnaires to 75 surgical-range, medical/interventional AIS patients and compared them. We performed analysis by regression modeling to produce conversion equations from SRS-24 to SRS-22r.

Results: The total SRS-24 score for these medical/interventional AIS patients was 92.5 ± 9.45 (mean, 3.9 ± 0.39), and the total SRS-22r score was 93.5 ± 9.63 (mean, 4.3 ± 0.44). The correlation between these 2 groups was fair (R = 0.77) and improved to good when mental health or recall questions were removed. The correlation was also fair for total pain domains (R = 0.73). However, there was poor correlation for general self-image (R = 0.6) and unacceptable for post-treatment self-image (R = 0.01), general function (R = 0.52), activity function (R = 0.56), and satisfaction (R = 0.53). Compared with a published population of operative AIS patients, R values for total SRS-24 scores, pain, general self-image, activity function, and satisfaction were similar (p > .05). The R values for general function and combined general and activity function were significantly different between the operative and medical/interventional cohorts.

Conclusions: Scoliosis Research Society-24 can be converted to SRS-22r scores with fair accuracy in the surgical-range, medical/interventional AIS patient population for total score, and total pain domains. The SRS-24 translates unacceptably to the SRS-22r in self-image, function, and satisfaction domains. The SRS-24 to SRS-22r conversion equations are similar to operative AIS patients, except for the function domain. Caution should be used when interpreting results based on translation of SRS-24 to SRS-22r values.
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http://dx.doi.org/10.1016/j.jspd.2012.12.003DOI Listing
March 2013

Order of Inoculation during Heligmosomoides bakeri and Hymenolepis microstoma Coinfection Alters Parasite Life History and Host Responses.

Pathogens 2013 Mar 1;2(1):130-52. Epub 2013 Mar 1.

Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92096, USA.

Parasite life history may differ during coinfection compared to single infections, and the order of infection may be an important predictor of life history traits. We subjected laboratory mice (Mus musculus) to single and coinfections with Heligmosomoides bakeri and Hymenolepis microstoma and measured life history traits of worms and also hepatobiliary and morphological responses by the host. We found that fewer H. bakeri larvae established, and adult worms were shorter and produced fewer eggs during a coinfection where H. microstoma occurred first. H. microstoma grew more and released more eggs after simultaneous inoculation of both parasites compared to a single H. microstoma infection, despite similar worm numbers. Mouse small intestine mass, but not length, varied with coinfection and bile duct mass was largest when H. microstoma was given alone or first. Mouse serum alkaline phosphatase levels were greatest for mice infected with H. microstoma only but did not vary with number of scolices; no change in mouse serum alanine transaminase levels was observed. Overall, the order of coinfection influenced life history traits of both H. bakeri and H. microstoma, but changes in survival, growth, and reproduction with order of inoculation were not consistent between the two parasites.
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http://dx.doi.org/10.3390/pathogens2010130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4235709PMC
March 2013

Osteoid osteoma of the lumbar spine.

Spine J 2012 Oct 22;12(10):971-2. Epub 2012 Oct 22.

University of Pittsburgh Medical Center, Kaufmann Medical Building, Suite 1010, 3471 Fifth Ave., Pittsburgh, PA 15213, USA.

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http://dx.doi.org/10.1016/j.spinee.2012.08.176DOI Listing
October 2012

Ritual Black Drink consumption at Cahokia.

Proc Natl Acad Sci U S A 2012 Aug 6;109(35):13944-9. Epub 2012 Aug 6.

Department of Anthropology, University of New Mexico, Albuquerque, NM 87131, USA.

Chemical analyses of organic residues in fragments of pottery from the large site of Cahokia and surrounding smaller sites in Illinois reveal theobromine, caffeine, and ursolic acid, biomarkers for species of Ilex (holly) used to prepare the ritually important Black Drink. As recorded during the historic period, men consumed Black Drink in portions of the American Southeast for ritual purification. This first demonstrated discovery of biomarkers for Ilex occurs in beaker vessels dating between A.D. 1050 and 1250 from Cahokia, located far north of the known range of the holly species used to prepare Black Drink during historic times. The association of Ilex and beaker vessels indicates a sustained ritual consumption of a caffeine-laced drink made from the leaves of plants grown in the southern United States.
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http://dx.doi.org/10.1073/pnas.1208404109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435207PMC
August 2012
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