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2.
Cureus ; 15(3): e36299, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37077591

RESUMO

INTRODUCTION: YouTube is an open-source platform where creators can record and upload videos for others to see. As the popularity of YouTube increases, it is being increasingly used for healthcare-related information. However, with the relative ease of uploading videos, the content quality of individual videos is not regulated. This study aimed to assess and analyze the content quality of YouTube videos concerning meniscus tear rehabilitation. We hypothesized that most videos would be of low quality. METHODS: The keywords "meniscus tear treatment," "meniscus tear recovery," "meniscus tear physical therapy," and "meniscus tear rehabilitation" were used for searching videos on YouTube. A total of 50 videos was analyzed in this study that related to meniscal rehabilitation, grouped into one of four categories: non-physician professionals (physical therapists and chiropractors) (n=28), physicians (with or without academic affiliation) (n=5), non-academic healthcare-related websites (n=10), and non-professional individuals (n=7). Videos were then assessed by two independent authors using three scoring systems, which included the Global Quality Scale (GQS), modified DISCERN, and Journal of the American Medical Association (JAMA) scores. The number of likes, comments, video length, and views were collected for each video. Kruskal-Wallis tests were used to compare quality scores and video analytics. RESULTS: The overall median GQS, modified DISCERN, and JAMA scores were 3 (interquartile range (IQR): 2-3), 2 (IQR: 2-2), and 2 (IQR: 2-2), respectively. Sorted by GQS scores, 20 videos were of low quality (40%), 21 were intermediate (42%), and nine were of high quality (18%). Non-physician professionals produced 56% (28 of 50) of the videos assessed, with physical therapists constituting 86% (24 of 28) of this category. The median duration of each video was 6:54 (IQR: 3:59-10:50) minutes, views was 42,262 (IQR: 12,373-306,491), and likes was 877 (IQR: 239-4,850). Kruskal-Wallis testing showed a significant difference between JAMA scores, likes, and video length duration between video categories (p<0.028). CONCLUSION: The overall median reliability of YouTube videos on meniscus tear rehabilitation measured by JAMA and modified DISCERN scores was low. The overall median video quality, as assessed by GQS scores, was intermediate. Video quality was highly variable, with fewer than 20% meeting high-quality standards. As a result, patients are often viewing lower quality videos when researching their condition online.

3.
Parasit Vectors ; 16(1): 58, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36755300

RESUMO

The diagnostics of ruminant parasites remains one of the cornerstones for parasite control best practices. Field veterinarians have several techniques at their disposal (fecal egg count, coproculture, FAMACHA®, plasma pepsinogen, ELISA-Ostertagia, ELISA-Fasciola, Baermann and ELISA-Lungworm) for the identification and/or quantification of gastrointestinal nematodes, lungworms and liver fluke infecting small ruminants and cattle. Each of these diagnostic tools has its own strengths and weaknesses and is more appropriate for a specific production operation and/or age of the animal (young and adults). This review focuses on the usability and interpretation of the results of these diagnostic tools. The most advanced technical information on sampling, storage, advantages and limitations of each tool for different types of production operations and animal categories is provided.


Assuntos
Doenças dos Bovinos , Fasciola hepatica , Nematoides , Animais , Bovinos , Ruminantes , Fezes/parasitologia , Doenças dos Bovinos/parasitologia , Contagem de Ovos de Parasitas/veterinária
4.
Am J Physiol Renal Physiol ; 323(1): F48-F58, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35635324

RESUMO

Silica nanoparticles (SiNPs) released during the burning of sugarcane have been postulated to have a role in chronic kidney disease of unknown etiology. We tested the hypothesis that pristine SiNPs of the size present in sugarcane might cause chronic kidney injury when administered through the lung in rats. We administered 200- or 300-nm amorphous SiNPs twice weekly (4 mg/dose), or vehicle by oropharyngeal aspiration for 13 wk to rats followed by euthanasia after an additional 13 wk (26 wk total). Tissues were evaluated for the presence of SiNPs and evidence of histological injury. Both sizes of SiNPs caused kidney damage, with early tubular injury and inflammation (at week 13) that continued to inflammation and chronic fibrosis at week 26 despite discontinuation of the SiNP administration. Both sizes of SiNPs caused local inflammation in the lung and kidney and were detected in the serum and urine at week 13, and the 200-nm particles were also localized to the kidney with no evidence of retention of the 300-nm particles. At week 26, there was some clearance of the 200-nm silica from the kidneys, and urinary levels of SiNPs were reduced but still significant in both 200- and 300 nm-exposed rats. In conclusion, inhaled SiNPs cause chronic kidney injury that progresses despite stopping the SiNP administration. These findings support the hypothesis that human exposure to amorphous silica nanoparticles found in burned sugarcane fields could have a participatory role in chronic kidney disease of unknown etiology.NEW & NOTEWORTHY Inhalation of silica nanoparticles (SiNPs) released during the burning of sugarcane has been postulated to have a role in chronic kidney disease of unknown etiology (CKDu). We administered 200- and 300-nm amorphous SiNPs to rats by aspiration and observed kidney damage with tubular injury and inflammation that persisted even after stopping the SiNP exposure. These findings support the hypothesis that human exposure to SiNPs found in sugarcane ash could have a participatory role CKDu.


Assuntos
Nanopartículas , Insuficiência Renal Crônica , Animais , Inflamação/patologia , Pulmão/patologia , Nanopartículas/toxicidade , Ratos , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal Crônica/patologia , Dióxido de Silício/toxicidade
5.
JAMA Netw Open ; 4(9): e2126447, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34550382

RESUMO

Importance: Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings. Objectives: To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning. Design, Setting, and Participants: This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. Wastewater, air, and surface samples were collected weekly and tested for SARS-CoV-2 RNA to evaluate surrogacy for case detection and interrogate transmission risk of in-building activities. Main Outcomes and Measures: SARS-CoV-2 detection in saliva and environmental samples and risk factors for SARS-CoV-2 infection. Results: A total of 2885 supervised, self-collected saliva samples were tested from 458 asymptomatic staff members (mean [SD] age, 42.9 [12.4] years; 303 women [66.2%]; 25 Black or African American [5.5%], 83 Hispanic [18.1%], 312 White [68.1%], and 35 other or not provided [7.6%]) and 315 students (mean age, 14.2 [0.7] years; 151 female students [48%]; 20 Black or African American [6.3%], 201 Hispanic [63.8%], 75 White [23.8%], and 19 other race or not provided [6.0%]). A total of 46 cases of SARS-CoV-2 (22 students and 24 staff members) were detected, representing an increase in cumulative case detection rates from 1.2% (12 of 1000) to 7.0% (70 of 1000) among students and from 2.1% (21 of 1000) to 5.3% (53 of 1000) among staff compared with conventional reporting mechanisms during the pilot period. SARS-CoV-2 RNA was detected in wastewater samples from all pilot schools as well as in air samples collected from 2 choir rooms. Sequencing of 21 viral genomes in saliva specimens demonstrated minimal clustering associated with 1 school. Geographical analysis of SARS-CoV-2 cases reported district-wide demonstrated higher community risk in zip codes proximal to the pilot schools. Conclusions and Relevance: In this study of staff and students in 3 urban public schools in Omaha, Nebraska, weekly screening of asymptomatic staff and students by saliva polymerase chain reaction testing was associated with increased SARS-CoV-2 case detection, exceeding infection rates reported at the county level. Experiences differed among schools, and virus sequencing and geographical analyses suggested a dynamic interplay of school-based and community-derived transmission risk. Collectively, these findings provide insight into the performance and community value of test-based SARS-CoV-2 screening and surveillance strategies in the kindergarten through 12th grade educational setting.


Assuntos
Teste para COVID-19/métodos , COVID-19/epidemiologia , Monitoramento Ambiental , Programas de Rastreamento , Avaliação de Programas e Projetos de Saúde , Instituições Acadêmicas , População Urbana , Adolescente , Adulto , Microbiologia do Ar , COVID-19/virologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nebraska , Pandemias , Projetos Piloto , Reação em Cadeia da Polimerase , Medição de Risco , SARS-CoV-2 , Saliva , Professores Escolares , Estudantes , Águas Residuárias/virologia
6.
Adv Chronic Kidney Dis ; 26(6): 409-416, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31831119

RESUMO

Vascular calcification (VC) is common in chronic kidney disease, increases in prevalence as patients progress to end-stage renal disease, and is significantly associated with mortality. VC is a complex and highly regulated process similar to bone formation whereby hydroxyapatite crystals deposit in the intimal or medial layer of arteries. Mineral bone abnormalities are common in chronic kidney disease; reduction in glomerular filtration rate and changes in vitamin D, parathyroid hormone, and fibroblast growth factor 23 result in the dysregulation of phosphorus and calcium metabolism. Cell culture studies, animal models, and observational and clinical studies all suggest this abnormal mineral metabolism plays a role in the initiation and progression of VC in kidney disease. This review will focus on these mineral bone abnormalities and how they may contribute to mechanisms that induce VC in kidney disease.


Assuntos
Insuficiência Renal Crônica/metabolismo , Calcificação Vascular/metabolismo , Animais , Cálcio/metabolismo , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos/metabolismo , Glucuronidase/metabolismo , Humanos , Proteínas Klotho , Hormônio Paratireóideo/metabolismo , Fósforo/metabolismo , Insuficiência Renal Crônica/complicações , Calcificação Vascular/etiologia , Vitamina D/metabolismo
7.
Front Psychol ; 9: 542, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29765341

RESUMO

Co-actors need to anticipate each other's actions to successfully perform joint actions. The frames of reference (FOR) used to simulate a co-actor's action could impact what information is anticipated. We hypothesized that co-actor's would adopt their co-actor's body-centered FOR, even when they do not share the same spatial orientation, so that they could anticipate body-related aspects of their co-actor's task. Because it might be beneficial to plan joint actions based on environment and body-centered information, we hypothesized that individuals would utilize multiple FORs during response planning. To test these hypotheses, participants performed a sequential aiming task where the goal was to move a wooden dowel to one of four potential targets as quickly and accurately as possible. A cue was presented at the beginning of each trial that was either 25, 50, or 75% valid. Following the cue presentation, the first person to act (initiator) placed the wooden dowel, anywhere they liked, in the workspace. Then, the finisher performed their aiming movement from the location that the initiator had placed the dowel. The key dependent measure was the dowel placement of the initiator because it provided an index of how much the initiator attempted to facilitate the efficient performance of the finisher. The results revealed that individuals adopted an allocentric FOR (dowel placement was more biased toward cued locations as cue validity increased) and partially adopted their co-actor's body-centered FOR (dowel placement was biased toward the finisher's body, but not toward the co-actor's contralateral space). In conclusion, multiple FORs can be used to anticipate both body- and environment-related information of a co-actor's task. It may be difficult, however, for individuals to fully adopt their co-actor's body-centered FOR when they have differing orientations.

8.
Hum Factors ; 60(1): 92-100, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29141158

RESUMO

Objective The aim of this study was to investigate the combined effect of cold and moisture on manual performance and tactile sensitivity. Background People working in the ocean environment often perform manual work in cold and wet conditions. Although the independent effects of cold and moisture on hand function are known, their combined effect has not been investigated. Method Participants completed sensory (Touch-Test, two-point discrimination) and motor (Purdue Pegboard, Grooved Pegboard, reef knot untying) tests in the following conditions: dry hand, wet hand, cold hand, and cold and wet hand. Results For the Purdue Pegboard and knot untying tasks, the greatest decrement in performance was observed in the cold-and-wet-hand condition, whereas the decrements seen in the cold-hand and wet-hand conditions were similar. In the Grooved Pegboard task, the performance decrements exhibited in the cold-and-wet-hand condition and the cold-hand condition were similar, whereas no decrement was observed in the wet-hand condition. Tactile sensitivity was reduced in the cold conditions for the Touch-Test but not the two-point discrimination test. CONCLUSION: The combined effect of cold and moisture led to the largest performance decrements except when intrinsic object properties helped with grasp maintenance. The independent effects of cold and moisture on manual performance were comparable. Application Tools and equipment for use in the cold ocean environment should be designed to minimize the effects of cold and moisture on manual performance by including object properties that enhance grasp maintenance and minimize the fine-dexterity requirements.


Assuntos
Temperatura Baixa , Desempenho Psicomotor/fisiologia , Percepção do Tato/fisiologia , Água , Adulto , Animais , Feminino , Humanos , Masculino , Oceanos e Mares , Adulto Jovem
9.
J Am Chem Soc ; 139(51): 18545-18551, 2017 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-29191021

RESUMO

Here, we highlight the ability of peri-substitution chemistry to promote a series of unique P-P/P-As coupling reactions, which proceed with concomitant C-H bond formation. This dealkanative reactivity represents an interesting and unexpected expansion to the established family of main-group dehydrocoupling reactions. These transformations are exceptionally clean, proceeding essentially quantitatively at relatively low temperatures (70-140 °C), with 100% diastereoselectivity in the products. The reaction appears to be radical in nature, with the addition of small quantities of a radical initiator (azobis(isobutyronitrile)) increasing the rate dramatically, as well as altering the apparent order of reaction. DFT calculations suggest that the reaction involves dissociation of a phosphorus centered radical (stabilized by the peri-backbone) to the P-P coupled product and a free propyl radical, which carries the chain. This unusual reaction demonstrates the powerful effect that geometric constraints, in this case a rigid scaffold, can have on the reactivity of main group species, an area of research that is gaining increasing prominence in recent years.

10.
Hum Factors ; 59(5): 811-820, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28704633

RESUMO

OBJECTIVE: To investigate the effect of hand immersion duration on manipulative ability and tactile sensitivity. BACKGROUND: Individuals in maritime settings often work with hands that have been immersed in water. Although research has shown that hand immersion duration differentially impacts skin adhesion and tactile sensitivity, the effect of hand immersion on manipulative ability has not been directly tested. Given how critical manipulative ability is for the safety and performance of those working at sea, the effect of hand immersion duration on manual performance was investigated. METHOD: Tests of manipulative ability (Purdue Pegboard, Grooved Pegboard, reef knot untying) and tactile sensitivity (Touch-Test) were completed following no-exposure, short-exposure, and long-exposure hand immersions in thermoneutral water. RESULTS: Compared to the no immersion condition, the Purdue Pegboard performance was reduced in both immersion conditions (short exposure, -11%; long exposure, -8%). A performance decrement was only observed in the short exposure condition (+15% in time to complete task) for the reef knot untying task. There were no statistical differences in the Grooved Pegboard or Touch-Test scores between exposure conditions. CONCLUSION: Immersing the hands in water decreases manipulative ability except for when object properties reduce the slipperiness between the hand and object. APPLICATION: Manual performance in a wet environment may be conserved by designing tools and objects with edges and textures that can offset the slipperiness of wet hands. To maintain safety, the time requirements for working with wet hands needs to be considered.


Assuntos
Mãos/fisiologia , Imersão , Atividade Motora/fisiologia , Desempenho Psicomotor/fisiologia , Percepção do Tato/fisiologia , Tato/fisiologia , Adulto , Humanos , Fatores de Tempo , Água
11.
Hum Mov Sci ; 54: 197-209, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28527422

RESUMO

Co-actors can facilitate the achievement of a shared goal by accurately anticipating each other's needs and subsequently planning actions to accommodate those needs. The purpose of the present study was to determine if co-actors plan and execute their movements to accommodate the difficulty of their partners' action. We hypothesized that information derived from shared task representations could influence the simulation of other's actions and that motor experience would enhance the ability of co-actor's to anticipate their co-actor's needs. Partners performed a sequential aiming task. The initiator of the sequential action placed a dowel on a line between two potential targets that varied in size across trials. The initiator did not know the actual target location prior to placing the dowel. The finisher then grasped the dowel and moved it to whichever target was signaled, from wherever their partner had placed the dowel. Participants completed the partner task before and after completing an individual task in which they completed both the initiating and the finishing movements. Consistent with the prediction that co-actors represent the difficulty of their partners' actions, the dowel was placed closer to the smaller target of a pair. Further, it was found that motor experience influenced dowel placement - there was a shift in dowel placement following the completion of the individual task. These results indicate that co-actors plan their movements based on features of their co-actor's movements and that motor experience provides information that allows people to better plan movements for their partners.


Assuntos
Antecipação Psicológica/fisiologia , Desempenho Psicomotor/fisiologia , Análise de Variância , Comportamento Cooperativo , Feminino , Humanos , Masculino , Movimento/fisiologia , Adulto Jovem
12.
Foot Ankle Int ; 37(10): 1119-1129, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27354397

RESUMO

BACKGROUND: Foot and ankle movement alterations following ankle arthrodesis are still not well understood, particularly those that might contribute to the documented increase in adjacent joint arthritis. Generalized tarsal hypermobility has long been postulated, but not confirmed in gait or functional movements. The purpose of this study was to more thoroughly evaluate compensation mechanisms used by arthrodesis patients during level and uphill gait through a variety of measurement modalities and a detailed breakdown of gait phases. METHODS: Level ground and uphill gait of 14 unilateral tibiotalar arthrodesis patients and 14 matched controls was analyzed using motion capture, force, and pressure measurements in conjunction with a kinetic multisegment foot model. RESULTS: The affected limb exhibited several marked differences compared to the controls and to the unaffected limb. In loading response, ankle eversion was reduced but without a reduction in tibial rotation. During the second rocker, ankle dorsiflexion was reduced, yet was still considerable, suggesting compensatory talar articulation (subtalar and talonavicular) motion since no differences were seen at the midtarsal joint. Also during the second rocker, subjects abnormally internally rotated the tibia while moving their center of pressure laterally. Third rocker plantarflexion motion, moments, and powers were substantially reduced on the affected side and to a lesser extent on the unaffected side. CONCLUSION: Sagittal plane hypermobility is probable during the second rocker in the talar articulations following tibiotalar fusion, but is unlikely in other midfoot joints. The normal coupling between frontal plane hindfoot motion and tibial rotation in early and mid stance was also clearly disrupted. These alterations reflect a complex compensatory movement pattern that undoubtedly affects the function of arthrodesis patients, likely alters the arthrokinematics of the talar joints (which may be a mechanism for arthritis development), and should be considered in future arthrodesis as well as arthroplasty research. LEVEL OF EVIDENCE: Level III, comparative study.


Assuntos
Articulação do Tornozelo/cirurgia , Artrodese , Marcha/fisiologia , Caminhada/fisiologia , Articulação do Tornozelo/fisiopatologia , Fenômenos Biomecânicos , Estudos de Casos e Controles , Pé/fisiologia , Humanos , Amplitude de Movimento Articular
13.
Dalton Trans ; 45(5): 1976-86, 2016 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-26314761

RESUMO

Bis(borane) adducts Acenap(PiPr2·BH3)(PRH·BH3) (Acenap = acenaphthene-5,6-diyl; 4a, R = Ph; 4b, R = ferrocenyl, Fc; 4c, R = H) were synthesised by the reaction of excess H3B·SMe2 with either phosphino-phosphonium salts [Acenap(PiPr2)(PR)](+)Cl(-) (1a, R = Ph; 1b, R = Fc), or bis(phosphine) Acenap(PiPr2)(PH2) (3). Bis(borane) adducts 4a-c were found to undergo dihydrogen elimination at room temperature, this spontaneous catalyst-free phosphine-borane dehydrocoupling yields BH2 bridged species Acenap(PiPr2)(µ-BH2)(PR·BH3) (5a, R = Ph; 5b, R = Fc; 5c, R = H). Thermolysis of 5c results in loss of the terminal borane moiety to afford Acenap(PiPr2)(µ-BH2)(PH) (14). Single crystal X-ray structures of 3, 4b and 5a-c are reported.

14.
J Patient Saf ; 12(4): 190-196, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-24583955

RESUMO

INTRODUCTION: Living wills are a form of advance directives that help to protect patient autonomy. They are frequently encountered in the conduct of medicine. Because of their impact on care, it is important to understand the adequacy of current medical school training in the preparation of physicians to interpret these directives. METHODS: Between April and August 2011 of third and fourth year medical students participated in an internet survey involving the interpretation of living wills. The survey presented a standard living will as a "stand-alone," a standard living will with the addition an emergent clinical scenario and then variations of the standard living will that included a code status designation ("DNR," "Full Code," or "Comfort Care"). For each version/ scenario, respondents were asked to assign a code status and choose interventions based on the cases presented. RESULTS: Four hundred twenty-five students from medical schools throughout the country responded. The majority indicated they had received some form of advance directive training and understood the concept of code status and the term "DNR." Based on a stand-alone document, 15% of respondents correctly denoted "full code" as the appropriate code status; adding a clinical scenario yielded negligible improvement. When a code designation was added to the living will, correct code status responses ranged from 68% to 93%, whereas correct treatment decisions ranged from 18% to 78%. Previous training in advance directives had no impact on these results. CONCLUSION: Our data indicate that the majority of students failed to understand the key elements of a living will; adding a code status designations improved correct responses with the exception of the term DNR. Misunderstanding of advance directives is a nationwide problem and jeopardizes patient safety. Medical School ethics curricula need to be improved to ensure competency with respect to understanding advance directives.


Assuntos
Compreensão , Testamentos Quanto à Vida , Segurança do Paciente , Ordens quanto à Conduta (Ética Médica) , Estudantes de Medicina , Adulto , Diretivas Antecipadas , Feminino , Humanos , Masculino , Médicos , Inquéritos e Questionários
15.
Psychol Res ; 79(4): 650-7, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25009311

RESUMO

It is widely held that the spatial compatibility effect emerges because the irrelevant spatial dimension of the target stimulus activates a response simultaneous to the activation of a response to the relevant stimulus dimension. The non-target response facilitates response planning on compatible trials, but interferes with response planning on incompatible trials. In support of this hypothesis, the trajectories of aiming movements executed on incompatible trials deviate in the direction of the stimulus location. These deviations are thought to occur because the characteristics of the simultaneously active target and non-target responses merge. Previously, target stimuli were presented at the target locations leaving open the possibility that the response activation and subsequent deviations were dependent on the stimulus-driven attentional capture associated with the dynamic change of stimulus onset. The present research was conducted to determine if attention capturing events at the target locations were necessary for the movement deviations to emerge by investigating if trajectory deviations are also observed when the spatial dimension is presented centrally. Participants in the Central condition aimed to left and right target locations based on the color of a ring worn on a finger that pointed toward the response locations. Similar to results from a Peripheral condition, trajectory deviations were observed in the Central condition. Although it is unclear if the deviations in the Central condition occurred because of attentional shifts driven by the cue or response preplanning, these results demonstrate that dynamic changes at target locations are sufficient, but not necessary, to generate trajectory deviations.


Assuntos
Atenção/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
16.
Inorg Chem ; 53(16): 8538-47, 2014 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-25073081

RESUMO

Coordination chemistry of an acenaphthene peri-backbone-supported phosphino-phosphonium chloride (1) was investigated, revealing three distinct modes of reactivity. The reaction of 1 with Mo(CO)4(nor) gives the Mo(0) complex [(1)Mo(CO)4Cl] (2), in which the ligand 1 exhibits monodentate coordination through the phosphine donor and the P-P bond is retained. PtCl2(cod) reacts with the chloride and triflate salts of 1 to form a mononuclear complex [(1Cl)PtCl2] (3) and a binuclear complex [((1Cl)PtCl)2][2TfO] (4), respectively. In both of these complexes, the platinum center adds across the P-P bond, and subsequent chloride transfer to the phosphenium center results in phosphine-chlorophosphine bidentate coordination. [((1)PdCl)2] (5) was isolated from the reaction of 1 and Pd2(dba)3 (dba = dibenzylideneacetone). Oxidative addition to palladium(0) results in a heteroleptic phosphine bridging phosphide coordination to the Pd(II) center. In addition, reaction of 1 with BH3·SMe2 leads to the bis(borane) adduct of the corresponding mixed tertiary/secondary phosphine (6), with BH3 acting as both a reducing agent and a Lewis acid. The new compounds were fully characterized, including X-ray diffraction. The ligand properties of 1 and related bonding issues are discussed with help of DFT computations.

17.
PLoS One ; 9(1): e85961, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24465813

RESUMO

According to action-centered models of attention, the patterns of distractor interference that emerge in selective reaching tasks are related to the time and effort required to resolve a race for activation between competing target and non-target response producing processes. Previous studies have only used unimanual aiming tasks and, as such, only examined the effects of competition that occurs within a limb. The results of studies using unimanual aiming movements often reveal an "ipsilateral effect"--distractors on the same side of space as the effector cause greater interference than distractors on the opposite side of space. The cost of the competition when response selection is between the limbs has yet to be addressed. Participants in the present study executed reaching movements to 1 of 4 (2 left, 2 right) possible target locations with and without a distractor. Participants made ipsilateral reaches (left hand to left targets, right hand to right targets). In contrast to studies using unimanual aiming movements, a "contralateral effect" was observed; distractors affording responses for the other hand (in contralateral space) caused more interference than distractors affording responses for the same hand. The findings from the present research demonstrate that when certain portions of response planning must be resolved prior to response initiation, distractors that code for that dimension cause the greatest interference.


Assuntos
Comportamento de Escolha/fisiologia , Extremidades/fisiologia , Movimento/fisiologia , Análise e Desempenho de Tarefas , Adolescente , Adulto , Feminino , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia , Adulto Jovem
18.
Hum Mov Sci ; 32(3): 400-11, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23632202

RESUMO

Repeated action observation has been shown to alter the cortical representation of the observed movement in the motor system. This change in cortical representation is thought to reflect a motor adaptation to observational training (observational training effect). One factor that may impact the observational training effect is the degree of motor system activation that occurs during the observation of the action (i.e., individual differences in the responsiveness of the motor system during action observation). The present study was conducted to test this hypothesis by assessing the relationship between the change in motor system activity during action observation and the change in cortical representation of action following repeated action observation. To this end, transcranial magnetic stimulation (TMS) was used to evoke contractions of thumb muscles in two different protocols: 1) during the observation of thumb movements to assess the responsiveness of each individual's corticospinal system during action observation; and, 2) after the observation of 1800 thumb movements to assess the amount of adaptation in the representation of the thumb following repeated action observation. The key finding was the significant positive relationship between the level of corticospinal system activation during action observation and the amount of change in the direction of TMS evoked thumb movements. These data support the hypothesized relationship between motor system activation during action observation and the motor systems adaptation following observational training. They are also consistent with the notion that a common neural mechanism underlies these effects.


Assuntos
Córtex Cerebral/fisiologia , Atividade Motora/fisiologia , Neurônios Motores/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/inervação , Tratos Piramidais/fisiologia , Polegar/inervação , Estimulação Magnética Transcraniana , Percepção Visual/fisiologia , Adulto , Nível de Alerta/fisiologia , Atenção/fisiologia , Eletromiografia , Feminino , Humanos , Masculino , Rememoração Mental/fisiologia , Destreza Motora/fisiologia , Processamento de Sinais Assistido por Computador , Adulto Jovem
19.
Inorg Chem ; 52(8): 4346-59, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23534381

RESUMO

Coupling of two acenaphthene backbones through a phosphorus atom in a geminal fashion gives the first geminally bis(peri-substituted) tridentate phosphine 1. The rigid nature of the aromatic backbone and overall crowding of the molecule result in a rather inflexible ligand, with the three phosphorus atoms forming a relatively compact triangular cluster. Phosphine 1 displays restricted dynamics on an NMR time scale, which leads to the anisochronicity of all three phosphorus nuclei at low temperatures. Strained bis- and tris(sulfides) 2 and 3 and the bis(selenide) 4 have been isolated from the reaction of 1 with sulfur and selenium, respectively. These chalcogeno derivatives display pronounced in-plane and out-of-plane distortions of the aromatic backbones, indicating the limits of their angular distortions. In addition, we report metal complexes with tetrahedral [(1)Cu(MeCN)][BF4] (5), square planar [(1)PtCl][Cl] (6), trigonal bipyramidal [(1)FeCl2] (7), and octahedral fac-[(1)Mo(CO)3] (8) geometries. In all of these complexes the tris(phosphine) backbone is distorted, however to a significantly smaller extent than that in the mentioned chalcogenides 2-4. Complexes 5 and 8 show fluxionality in (31)P and (1)H NMR. All new compounds 1-8 were fully characterized, and their crystal structures are reported. Conclusions from dynamic NMR observations were augmented by DFT calculations.

20.
J Mot Behav ; 45(1): 1-5, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23387518

RESUMO

Numerous studies have revealed that when people sit next to each other and complete separate parts of a Simon task, response times are shorter when the participants' stimulus appears in front of them than when the stimulus appears in the opposite side of space. According to the action co-representation account of this joint Simon effect (JSE), participants represent each other's responses and the compatibility effects emerge because of a set of facilitatory and inhibitory processes that are similar to those that are activated when individuals perform the entire Simon task alone. D. Guagnano, E. Rusconi, and C. A. Umiltà (2010) argued against this account as the sole mechanism based on their finding that a JSE was not observed when participants sat outside of each other's peripersonal space. Notably, the task in the Guagnano et al.'s was a modified version of the conventional JSE task designed to increase the independence of the partners. Here, we reconsider the arguments of Guagnano et al. and report a study in which the authors failed to replicate their key finding. Considering the extant JSE literature, we conclude that the null effect in Guagnano et al.'s study may be an anomaly and that co-representation remains a leading candidate for the critical process underlying JSEs.


Assuntos
Comportamento de Escolha , Comportamento Cooperativo , Tempo de Reação , Detecção de Sinal Psicológico , Feminino , Humanos , Masculino
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