Kinematics and statics of cable-driven parallel robots by interval-analysis-based methods

In the past two decades the work of a growing portion of researchers in robotics focused on a particular group of machines, belonging to the family of parallel manipulators: the cable robots. Although these robots share several theoretical elements with the better known parallel robots, they still present completely (or partly) unsolved issues. In particular, the study of their kinematic, already a difficult subject for conventional parallel manipulators, is further complicated by the non-linear nature of cables, which can exert only efforts of pure traction. The work presented in this thesis therefore focuses on the study of the kinematics of these robots and on the development of numerical techniques able to address some of the problems related to it. Most of the work is focused on the development of an interval-analysis based procedure for the solution of the direct geometric problem of a generic cable manipulator. This technique, as well as allowing for a rapid solution of the problem, also guarantees the results obtained against rounding and elimination errors and can take into account any uncertainties in the model of the problem. The developed code has been tested with the help of a small manipulator whose realization is described in this dissertation together with the auxiliary work done during its design and simulation phases.

Surgical treatment of upper, middle and lower cervical injuries and non-unions by anterior procedures

The goals of any treatment of cervical spine injuries are: return to maximum functional ability, minimum of residual pain, decrease of any neurological deficit, minimum of residual deformity and prevention of further disability. The advantages of surgical treatment are the ability to reach optimal reduction, immediate stability, direct decompression of the cord and the exiting roots, the need for only minimum external fixation, the possibility for early mobilisation and clearly decreased nursing problems. There are some reasons why those goals can be reached better by anterior surgery. Usually the bony compression of the cord and roots comes from the front therefore anterior decompression is usually the procedure of choice. Also, the anterior stabilisation with a plate is usually simpler than a posterior instrumentation. It needs to be stressed that closed reduction by traction can align the fractured spine and indirectly decompress the neural structures in about 70%. The necessary weight is 2.5 kg per level of injury. In the upper cervical spine, the odontoid fracture type 2 is an indication for anterior surgery by direct screw fixation. Joint C1/C2 dislocations or fractures or certain odontoid fractures can be treated with a fusion of the C1/C2 joint by anterior transarticular screw fixation. In the lower and middle cervical spine, anterior plating combined with iliac crest or fibular strut graft is the procedure of choice, however, a solid graft can also be replaced by filled solid or expandable vertebral cages. The complication of this surgery is low, when properly executed and anterior surgery may only be contra-indicated in case of a significant lesion or locked joints.

Spectral-domain optical coherence tomography use in macular diseases: a review

The introduction of spectral-domain optical coherence tomography (SD-OCT) has improved the clinical value for assessment of the eyes with macular disease. This article reviews the advances of SD-OCT for the diagnostic of various macular diseases. These include vitreomacular traction syndrome, cystoid macular edema/diabetic macular edema, epiretinal membranes, full-thickness macular holes, lamellar holes, pseudoholes, microholes, and schisis from myopia. Besides offering new insights into the pathogenesis of macular abnormalities, SD-OCT is a valuable tool for monitoring macular disease.

Macular edema: Miscellaneous

Abstract. This article provides the reader with practical information to be applied to the various remaining causes of macular edema. Some macular edemas linked to ocular diseases like radiotherapy after ocular melanomas remained of poor functional prognosis due to the primary disease. On the contrary, macular edemas occurring after retinal detachment or after some systemic or local treatment use are often temporary. Macular edema associated with epiretinal membranes or vitreomacular traction is the main cause of poor functional recovery. However, the delay to observe a significant improvement of vision after surgery should be long, as usually observed in tractional myopic vitreoschisis. Finally, some circumstances of macular edemas such as hemangiomas or macroaneurysms should be treated, if symptomatic, with the treatments currently used in diabetic macular edema or exudative macular degeneration.

Macular edema. Miscellaneous

This chapter provides the reader with practical information to be applied to the various remaining causes of macular edema. Some clinical cases of macular edema linked to ocular diseases like postradiotherapy for ocular melanomas remained of poor functional prognosis due to the primary disease. On the contrary, macular edema occurring after retinal detachment or after diverse systemic or local treatment use is often temporary. Macular edema associated with epiretinal membranes or vitreomacular traction is the main cause of poor functional recovery. In other cases, as in tractional myopic vitreoschisis, the delay to observe a significant improvement of the vision after surgery should be long. Finally, macular edema associated with hemangiomas or macroaneurysms should be treated, if symptomatic, using the same current treatment as in diabetic macular edema or exudative macular degeneration.

Intralesional bovine papillomavirus DNA loads reflect severity of equine sarcoid disease

REASONS FOR PERFORMING STUDY: Sarcoids are nonmetastasising, yet locally aggressive skin tumours that constitute the most frequent neoplasm in equids. Infection by bovine papillomaviruses types 1 and 2 (BPV-1, BPV-2) has been recognised as major causative factor in sarcoid pathogenesis, but a possible correlation of intralesional virus load with disease severity has not been established thus far. HYPOTHESIS: Given the pathogenic role of BPV-1 and BPV-2 in sarcoid disease, we suggest that intralesional viral DNA concentration may reflect the degree of affection. METHODS: Severity of disease was addressed by recording the tumour growth kinetics, lesion number and tumour type for 37 sarcoid-bearing horses and one donkey. Viral load was estimated via quantitative real-time PCR (qPCR) of the E2, E5, L1 and L2 genes from the BPV-1/-2 genome for one randomly selected lesion per horse and correlated with disease severity. RESULTS: Quantitative PCR against E2 identified viral DNA concentrations ranging from 0-556 copies/tumour cell. Of 16 horses affected by quiescent, slowly growing single tumours or multiple mild-type lesions, 15 showed a viral load up to 1.4 copies per cell. In stark contrast, all equids (22/22) bearing rapidly growing and/or multiple aggressive sarcoids had a viral load between 3 and 569 copies per cell. Consistent results were obtained with qPCR against E5, L1 and L2. CONCLUSIONS: While tumours of the same clinical type carried variable virus load, confirming that viral titre does not determine clinical appearance, we identified a highly significant correlation between intralesional viral load and disease severity. POTENTIAL RELEVANCE: The rapid determination of BPV viral load will give a reliable marker for disease severity and may also be considered when establishing a therapeutic strategy.

Evaluation of administration of isoflurane at approximately the minimum alveolar concentration on depression of a nociceptive withdrawal reflex evoked by transcutaneous electrical stimulation in ponies

OBJECTIVE: To investigate effects of isoflurane at approximately the minimum alveolar concentration (MAC) on the nociceptive withdrawal reflex (NWR) of the forelimb of ponies as a method for quantifying anesthetic potency. ANIMALS: 7 healthy adult Shetland ponies. PROCEDURE: Individual MAC (iMAC) for isoflurane was determined for each pony. Then, effects of isoflurane administered at 0.85, 0.95, and 1.05 iMAC on the NWR were assessed. At each concentration, the NWR threshold was defined electromyographically for the common digital extensor and deltoid muscles by stimulating the digital nerve; additional electrical stimulations (3, 5, 10, 20, 30, and 40 mA) were delivered, and the evoked activity was recorded and analyzed. After the end of anesthesia, the NWR threshold was assessed in standing ponies. RESULTS: Mean +/- SD MAC of isoflurane was 1.0 +/- 0.2%. The NWR thresholds for both muscles increased significantly in a concentration-dependent manner during anesthesia, whereas they decreased in awake ponies. Significantly higher thresholds were found for the deltoid muscle, compared with thresholds for the common digital extensor muscle, in anesthetized ponies. At each iMAC tested, amplitudes of the reflex responses from both muscles increased as stimulus intensities increased from 3 to 40 mA. A concentration-dependent depression of evoked reflexes with reduction in slopes of the stimulus-response functions was detected. CONCLUSIONS AND CLINICAL RELEVANCE: Anesthetic-induced changes in sensory-motor processing in ponies anesthetized with isoflurane at concentrations of approximately 1.0 MAC can be detected by assessment of NWR. This method will permit comparison of effects of inhaled anesthetics or anesthetic combinations on spinal processing in equids.

Oral misoprostol for third stage of labor: a randomized placebo-controlled trial

OBJECTIVE: To investigate whether orally administered misoprostol during the third stage of labor is efficient in reducing postpartum blood loss. METHODS: In a double-masked trial, during vaginal delivery women were randomly assigned to receive a single oral dose of misoprostol (600 microg) or placebo in third stage of labor, immediately after cord clamping. The third stage of labor was managed routinely by early cord clamping and controlled cord traction; oxytocin was administered only if blood loss seemed more than usual. Blood loss was estimated by the delivering physician and differences in hematocrit were measured before and after delivery. RESULTS: Mean (+/- standard error of the mean) estimated blood loss (345 +/- 19.5 mL versus 417 +/- 25.9 mL, P = .031) and hematocrit difference (4.5 +/- 0.9% versus 7.9 +/- 1.2%, P = .014) were significantly lower in women who received misoprostol than those who received placebo. Fewer women in the misoprostol group had postpartum hemorrhage (blood loss of at least 500 mL), but that difference was not statistically significant (7% versus 15%, P = .43). Additional oxytocin before or after placental separation was used less often in the misoprostol group (16% versus 38%, P = .047). There were no differences in the length of third stage of labor (8 +/- 0.9 minutes versus 9 +/- 1 minutes, P = .947). There were no differences in pain during third stage of labor, postpartum fever, or diarrhea, but shivering was more frequent in the misoprostol group. CONCLUSION: Oral misoprostol administered in the third stage of labor reduced postpartum blood loss and might be effective in reducing incidence of postpartum hemorrhage.

Stereoselective pharmacokinetics of ketamine and norketamine after constant rate infusion of a subanesthetic dose of racemic ketamine or S-ketamine in Shetland ponies

OBJECTIVE: To evaluate pharmacokinetics of ketamine and norketamine enantiomers after constant rate infusion (CRI) of a subanesthetic dose of racemic ketamine or S-ketamine in ponies. ANIMALS: Five 6-year-old Shetland pony geldings that weighed between 101 and 152 kg. PROCEDURES: In a crossover study, each pony received a CRI of racemic ketamine (loading dose, 0.6 mg/kg; CRI, 0.02 mg/kg/min) and S-ketamine (loading dose, 0.3 mg/kg; CRI, 0.01 mg/kg/min), with a 1-month interval between treatments. Arterial blood samples were collected before and at 5, 15, 30, 45, and 60 minutes during drug administration and at 5, 10, 30, and 60 minutes after discontinuing the CRI. Plasma ketamine and norketamine enantiomers were quantified by use of capillary electrophoresis. Individual R-ketamine and S-ketamine concentration-versus-time curves were analyzed by use of a monocompartmental model. Plasma disposition curves for R-norketamine and S-norketamine were described by estimating the area under the concentration-versus-time curve (AUC), maximum concentration (Cmax), and time until Cmax. RESULTS: Plasma concentrations of S-ketamine decreased and biodegradation products increased more rapidly after S-ketamine CRI, compared with results after racemic ketamine CRI. The R-norketamine was eliminated faster than was the S-norketamine. Significant differences between treatments were found for the AUC of S-ketamine and within the racemic ketamine CRI for the AUC and Cmax of norketamine isomers. CONCLUSIONS AND CLINICAL RELEVANCE: CRI of S-ketamine may be preferable over CRI of racemic ketamine in standing equids because the S-enantiomer was eliminated faster when infused alone instead of as part of a racemic mixture.

Adipogenic and myogenic gene expression in rotator cuff muscle of the sheep after tendon tear

Chronic rotator cuff tendon tears lead to fatty infiltration and muscle atrophy with impaired physiological functions of the affected muscles. However, the cellular and molecular mechanisms of corresponding pathophysiological processes remain unknown. The purpose of this study was to characterize the expression pattern of adipogenic (PPARgamma, C/EBPbeta) and myogenic (myostatin, myogenin, Myf-5) transcription factors in infraspinatus muscle of sheep after tenotomy, implantation of a tension device, refixation of the tendon, and rehabilitation, reflecting a model of chronic rotator cuff tears. In contrast to human patients, the presented sheep model allows a temporal evaluation of the expression of a given marker in the same individual over time. Semiquantitative RT/PCR analysis of PPARgammaã, myostatin, myogenin, Myf-5, and C/EBPbeta transcript levels was carried out with sheep muscle biopsy-derived total RNA. We found a significantly increased expression of Myf-5 and PPARgamma after tenotomy and a significant change for Myf-5 and C/EBPbeta after continuous traction and refixation. This experimental sheep model allows the molecular analysis of pathomechanisms of muscular changes after rotator cuff tear. The results point to a crucial role of the transcription factors PPARgamma, C/EBPbeta, and Myf-5 in impairment and regeneration of rotator cuff muscles after tendon tears in sheep.

Reibschlüssige Greifsysteme für die automatische Handhabung im Materialfluss

Die personalintensive manuelle Durchführung notwendiger Handhabungsaufgaben im Materialfluss ist bedingt durch die oftmals vielfältig auftretenden charakteristischen Eigenschaften der zu behandelnden Stückgutobjekte. Typische Beispiele hierfür sind die Tätigkeiten des Kommissionierens und Sortierens, geprägt durch einen hohen Anteil manueller Tätigkeiten zur Handhabung wie: Vereinzeln, Greifen, Bewegen, Auf- und Abstapeln, Ordnen, Beladen und Ähnliche. Innovative Greifersysteme zur Stückguthandhabung eröffnen neue Möglichkeiten zur weiteren Automatisierung auch in diesem Bereich. Ein Lösungsansatz zur Entwicklung neuer Greifsysteme ist es, gezielt Friktionskräfte in Oberflächenbereiche des zu greifenden Objektes einzubringen und diese für den Handhabungsvorgang z.B. als Haltekräfte zu nutzen. Bei guten Reibwerten und entsprechender Anordnung der Wirkelemente können Objekte auch dann rein reibschlüssig gegriffen werden, wenn deren Oberfläche nur seitlich und von oben zugänglich ist, wie etwa Kartons im Packmusterverbund auf der Palette.

Entwicklung textiler Maschinenelemente für den Einsatz in Windkraftanlagen und Seilwinden

Es sollen hochfeste, gewichtreduzierte Zug- und Tragmittel aus hochmodularen (HM) und hochfesten (HT) Fasern validiert und dabei sowohl runde als auch flache, riemenartige Strukturen untersucht werden. Dadurch sind effizientere Fördersysteme und die Überwindung technischer Grenzen möglich. Darüber hinaus soll das Hauptkriterium für ein breites Anwendungsspektrum geschaffen werden: ein anerkanntes, zerstörungsfreies Prüfverfahren, mit dem der Austausch- bzw. Wartungszeitpunkt des textilen Tragmittels bestimmt werden kann. Können die o. g. Punkte erfolgreich bearbeitet werden, erfolgt eine Ausdehnung der textilen Strukturen in den Bereich kraftübertragender Maschinenelemente. Anhand von Feldversuchen in fördertechnischen Anlagen im Bergbau/ Intralogistik soll erstmals der vollständige Nachweis geführt werden, dass derartige textile Strukturen in technischen Anwendungen eingesetzt werden können. Der Nachweis umfasst die Validierung einer Vielzahl von Einzelschwerpunkten wie die Entwicklung einer Endlos-Herstellungstechnologie bzw. Endverbindung, die Tragmitteldimensionierung, die Erbringung von Festigkeitsnachweisen, die Erarbeitung von Vorschriften und die Erprobung der Verfahren zur Zustandsüberwachung.

Neue Generation von Aufzügen mit Faserseil

Energieeffiziente und leistungsfähige Zug- und Tragmittel aus hochmoduligen (HM) und hochfesten (HT) Fasern rücken seit einigen Jahren in den Fokus von Aufzugherstellern und Betreibern. Hauptgrund dafür ist, das die bisher eingesetzten Stahldrahtseile auf Grund ihrer vergleichsweise hohen Eigenmasse an technische Grenzen stoßen. Seile aus hochfesten Polymerfasern haben gegenüber Stahldrahtseilen eine vergleichbare oder sogar höhere Zugfestigkeit und ein vier- bis sechsfach geringeres Gewicht. Um das Potential dieser Fasern optimal auszunutzen, sind sowohl die Anordnung der Fasern als auch die Schmierstoffeinbringung zu untersuchen. Diesbezüglich wurden verschiedenen Seilkonstruktions- und Schmierstoffvarianten entwickelt und im Dauerbiegeversuch validiert.

Operative treatment of congenital hip osteoarthritis with high hip luxation (Crowe type IV)

OBJECTIVE The aim of the therapy is mechanical and functional stabilization of high dislocated hips with dysplasia coxarthrosis using total hip arthroplasty (THA). INDICATIONS Developmental dysplasia of the hip (DDH) in adults, symptomatic dysplasia coxarthrosis, high hip dislocation according to Crowe type III/IV, and symptomatic leg length inequality. CONTRAINDICATIONS Cerebrospinal dysfunction, muscular dystrophy, apparent disturbance of bone metabolism, acute or chronic infections, and immunocompromised patients. SURGICAL TECHNIQUE With the patient in a lateral decubitus position an incision is made between the anterior border of the gluteus maximus muscle and the posterior border of the gluteus medius muscle (Gibson interval). Identification of the sciatic nerve to protect the nerve from traction disorders by visual control. After performing trochanter flip osteotomy, preparation of the true actetabulum if possible. Implantation of the reinforcement ring, preparation of the femur and if necessary for mobilization, resection until the trochanter minor. Test repositioning under control of the sciatic nerve. Finally, refixation of the trochanteric crest. POSTOPERATIVE MANAGEMENT During hospital stay, intensive mobilization of the hip joint using a continuous passive motion machine with maximum flexion of 70°. No active abduction and passive adduction over the body midline. Maximum weight bearing 10-15 kg for 8 weeks, subsequently, first clinical and radiographic follow-up and deep venous thrombosis prophylaxis until full weight bearing. RESULTS From 1995 to 2012, 28 THAs of a Crow type IV high hip-dislocation were performed in our institute. Until now 14 patients have been analyzed during a follow-up of 8 years in 2012. Mid-term results showed an improvement of the postoperative clinical score (Merle d'Aubigné score) in 86 % of patients. Good to excellent results were obtained in 79 % of cases. Long-term results are not yet available. In one case an iatrogenic neuropraxia of the sciatic nerve was observed and after trauma a redislocation of the arthroplasty appeared in another case. In 2 cases an infection of the THA appeared 8 and 15 months after index surgery. No pseudoarthrosis of the trochanter or aseptic loosening was noticed.

Computed tomographic and radiographic examination of dental structures in South American camelid specimen of different ages.

BACKGROUND Tooth root problems and periodontal diseases are common in South American camelids (SAC). The objective was to evaluate and optimize the imaging technique for dental radiography in SAC and to describe the radiographic and computed tomographic (CT) anatomy of normal teeth at different ages. In this study, the heads of 20 healthy SAC slaughtered for meat production or euthanized for reasons not related to dental problems included 7 female and 10 male llamas and 3 male alpacas. Using a standardized protocol, radiographs and CT scans of the 20 specimen were performed. RESULTS The most useful radiographic projections for mandibular and maxillary cheek teeth evaluation turned out to be lateral30°ventral-laterodorsal and lateral30°dorsal-lateroventral with slight separation of the dental arcades respectively. Digital radiographic and CT appearance of the mandibular and maxillary teeth were described from the beginning of mineralization till maturity. In addition the normal range of the CT radio density of different cheek teeth and different dental tissues were measured. Hounsfield units of different dental tissues of SAC turned out to be similar to equids. Deviation, shortening and partial destruction of the distal tooth root of mandibular 09's and 10's and of maxillary 09's was observed and the existence of a common pulp chamber in younger teeth was revealed. CONCLUSIONS The present study provides information about the dental imaging morphology in clinically healthy SAC. This basic information provides fundamental knowledge for evaluating images and planning treatments in clinically affected animals.