1,721,089 research outputs found
Genesis of the Chirality of Polythiophene Aggregates from Classical Molecular Dynamics
No full textConjugated polymers are widely used in electronic devices whose performance is highly dependent on their electronic properties. Properties and performance are influenced by the supramolecular organization of the chromophores constituting the polymer backbone, and identifying structure-property relationships is crucial to design better devices. Polythiophenes (PTs) are among the most-studied polymers, and their ordered aggregation in solution is often induced by the introduction of chiral side chains. This allows using chiroptical spectroscopy, such as electronic circular dichroism, to monitor aggregation, but since experimental atomistic demonstrations of aggregate arrangements are lacking, computational models have been developed to identify the most likely structure. In this work, we simulate the aggregation of chiral polythiophenes by using classical molecular dynamics. Standard simulations show the formation of aggregates with herringbone arrangements, typical of polycyclic aromatic hydrocarbon crystals and also known for P3HT, the most used polythiophene, rather than the chiral H aggregates proposed in the literature. We exploited Hamiltonian Replica Exchange simulations to explore a larger portion of the free energy surface in the search for chiral conformations that would explain the experimentally observed chiroptical response. We identified cisoid and transoid helical structures with intramolecular chirality, without the formation of pi-stacked helical aggregates commonly suggested, which resulted unstable. Given past studies of the spectroscopic response of these structures, we assign the genesis of the chirality of polythiophene aggregates to intramolecular arrangements of polymer chains, rather than to interactions among different chains organized in a chiral fashion
Radiographic measurement of the quadriceps angle in dogs.
Full text linkThe direction of the force of the quadriceps muscle group is expressed by the value of the quadriceps angle, between the long axis of the muscle rectus femoris and the patellar ligament. This value is often modified in dogs with patellar luxation, a common orthopaedic disease of the stifle joint in both small and large dogs. The aims of the present study were to give a reference value for the quadriceps angle in healthy small and medium-large breed dogs. The medical records of healthy dogs and their pelvic limb radiographs (2014-2016) were reviewed. The radiographs were then divided into two groups: Group A (small dogs 15 kg). The quadriceps angle of each pelvic limb was assessed using a digital software program in order to compare values between the two groups. The radiographs of 160 dogs, 80 per group were studied along with the assessment of the 320 pelvic limbs. The median quadriceps angle values obtained were in contrast with the literature: in Group A, it was 18.3° and, in Group B, it was 8.7°; moreover, the quadriceps angle value for Group A was statistically higher than for Group B (p<0.0001). No significant difference was present between males and females, or between right and left hindlimbs. In Group B, the Labrador Retriever breed influenced the quadriceps angle (p = 0.0005). The outcome of this survey provides an objective parameter, or additional information, to explain the different quadriceps mechanisms of small and medium-large dogs. In future studies the QA range values assessed in the two size groups may be useful in defining the magnitude of the malalignment of the extensor mechanism in both healthy dogs and ones with patellar luxation
Occurrence of Incisional Complications After Closure of Equine Ventral Midline Celiotomies With 2 Polyglycolic Acid in Simple Interrupted Suture Pattern
No full textThe aim of this retrospective study was to describe the use of simple interrupted suture pattern for the closure of the abdomen after ventral midline celiotomy in horses and to evaluate the prevalence of resulting incisional complications. Seventy horses undergoing abdominal surgery (2006–2015) and surviving at least 30 days were included in the study. Closure technique of the abdominal wall was performed on three layers. Linea alba was closed with a simple interrupted pattern using number two coated braided absorbable polyglycolic acid suture. Follow-up information was recovered at the 90th day postoperatively. Incisional complications considered included drainage, infection, dehiscence, and herniation. The complications observed in the present study using simple interrupted suture pattern were 4.29% (3 of 70), lower than reported in literature with different suture pattern. Simple interrupted suture pattern could be a valid option for the closure of linea alba after ventral midline celiotomy in horses
Evidence-Based Veterinary Medicine: a tool for evaluating the healing process after surgical treatment for cranial cruciate ligament rupture in dogs
Full text linkThis study aims to validate a tool, the Bologna healing stifle injury index (BHSII), for the evaluation of the clinical picture and the healing after surgical treatment for cranial cruciate ligament (CCL) rupture. The study included 158 client-owned dogs with CCL rupture and 20 healthy dogs. The BHSII is a questionnaire made up of 34 multiple-choice questions, divided into a part directed to the clinician and a part for the dog's owners. It was applied twice in the healthy dogs in order to test and retest the device. It was evaluated for reliability, validity, and responsiveness to clinical changes involving the dogs treated at the time of surgery, and 1, 3, and 6 months postoperatively. Statistical analyses were performed and the intraclass correlation coefficient test was ≥0.9 and the Cronbach-α was 0.84 suggesting good stability and good internal consistency of the tool. The area under the curve of the receiver operating characteristic curve was >0.9, indicative of the high accuracy of this tool. The clinician survey correlated with the owner questionnaire. In dogs with CCL rupture, the scores of the BHSII increased significantly postoperatively as compared with baseline. In conclusion, this clinical study proved the reliability, validity, and responsiveness of the BHSII. The results achieved from the BHSII provided an instantaneous, collective complete vision of the healing process of the stifle joints treated. It can be considered a valid tool for collecting data and for assessing successful surgical treatment in clinical practice
Short-term General Anesthesia With Tiletamine/Zolazepam in Horses Sedated With Medetomidine for Castration Under Field Conditions
No full textThe objective of the study is to evaluate the anesthetic effect produced by the tiletamine/zolazepamassociation in horses sedated with medetomidine undergoing orchiectomy underfield conditions. Tenuncastrated male horses, American Society of Anesthesiologists category I, undergoing orchiectomy,were enrolled in the study. The horses received acepromazine (0.03 mg kg1intramuscularly) 30 mi-nutes before sedation with medetomidine (8mgkg1intravenously). Anesthesia was induced withtiletamine/zolazepam (0.7 mg kg1intravenously). During anesthesia, heart rate (HR), pulse quality,respiratory rate, temperature, SpO2, movement, and reflexes were measured every 5 minutes. Arterialblood gases were evaluated before the premedication and during the surgical procedure. The quality ofinduction and recovery was recorded. The sedation was appropriate, and the quality of recovery wasevaluated as good. A statistically significant difference was revealed between the basal and intra-anesthesia HR. No differences were observed in blood gas parameters during the procedure. The re-sults suggested that general anesthesia produced with tiletamine/zolazepam for induction in horsessedated with medetomidine is suitable during orchiectomy underfield conditions
The influence of environmental variables on platelet concentration in horse platelet-rich plasma
Full text linkPlatelet-rich plasma (PRP) commonly refers to blood products which contain a higher platelet (PLT) concentration as compared to normal plasma. Autologous PRP has been shown to be safe and effective in promoting the natural processes of soft tissue healing or reconstruction in humans and horses. Variability in PLT concentration has been observed in practice between PRP preparations from different patients or from the same individual under different conditions. A change in PLT concentration could modify PRP efficacy in routine applications. The aim of this study was to test the influence of environmental, individual and agonistic variables on the PLT concentration of PRP in horses. Six healthy Standardbred mares were exposed to six different variables with a one-week washout period between variables, and PRP was subsequently obtained from each horse. The variables were time of withdrawal during the day (morning/evening), hydration status (overhydration/dehydration) treatment with anti-inflammatory drugs and training periods on a treadmill. The platelet concentration was significantly higher in horses treated with a non-steroidal anti-inflammatory drug (P= 0.03). The leukocyte concentration increased 2-9 fold with respect to whole blood in the PRP which was obtained after exposure to all the variable considered. Environmental variation in platelet concentration should be taken into consideration during PRP preparation
Clinical Evaluation of Intralesional Injection of Platelet-Rich Plasma for the Treatment of Proximal Suspensory Ligament Desmitis in Horses
No full textThe study clinically evaluated the effectiveness of autologous platelet-rich plasma (PRP), obtained using a double transfusion bag after an ultrasound-guided intralesion injection into an acute lesion of proximal portion of suspensory ligament (SL). Twenty horses with acute proximal suspensory ligament desmitis were included in the study. An ultrasound evaluation of the proximal region of the SL was carried out, and the cross-sectional area (CSA) percentage and fiber score alignment were determined. Four hundred fifty milliliters of blood was collected, and PRP was obtained by means of the buffy coat method, using a double transfusion bag. The PRP was injected into the lesion using an ultrasound guide. A long-term follow-up was carried out by means of a telephonic interview with the owner. The median CSA of the SL lesion at the first examination was 30%. The median platelet count in the PRP was 1,045 × 103 platelets/μL; the final concentration ranged from six to 20 times higher than the platelet blood count. Sixteen horses returned to activity within a period ranging from 12 to 24weeks from the last PRP injection, and four animals recidivated in different regions of suspensory ligament: midbody desmitis and medial branch. Clinical results confirm that the use of autologous PRP supports healing and reduces recurrence in acute SL lesions
Evaluation of agreement and trending ability between transpulmonary thermodilution and calibrated pulse contour and pulse power cardiac output monitoring methods against pulmonary artery thermodilution in anesthetized dogs
No full textTo assess agreement and trending ability of transpulmonary thermodilution (TPTD), calibrated pulse contour (PiCCO), and pulse power (PulseCO) methods compared to pulmonary artery thermodilution (PATD) for determination of cardiac output (CO) in anesthetized dogs
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