1,354,577 research outputs found
Sistem de orientare biaxială a unui panou fotovoltaic
No full textInvenţia se referă la energetică, în special la sisteme de orientare biaxială a panourilor fotovoltaice, şi poate fi utilizată la orientarea panourilor fotovoltaice după soare.
Sistemul de orientare biaxială a unui panou fotovoltaic conţine un panou fotovoltaic, un arbore de orientare a panoului fotovoltaic în plan meridional, şi un mecanism de rotaţie, constituit dintr-un reductor melcat şi un motor electric. Panoul fotovoltaic este unit articulat în partea lui de mijloc cu arborele şi cinematic cu mecanismul de rotaţie. În partea de jos panoul fotovoltaic este legat articulat prin intermediul unei tije cu o bucşă cilindrică. Pe suprafaţa de contact a arborelui cu bucşa este executat un canal sinusoidal, în care este amplasată o bilă. Tija conţine o bucşă filetată, care dintr-o parte este unită cu un capăt filetat al tijei, iar de altă parte bucşa este unită cu capătul opus al tijei prin intermediul unor bile.The invention relates to power engineering, in particular to photovoltaic panel biaxial orientation systems, and can be used in the orientation of photovoltaic panels by the sun.
The photovoltaic panel biaxial orientation system comprises a photovoltaic panel, a shaft for orientation of the photovoltaic panel in the meridional plane, and a rotation mechanism, consisting of a worm reduction gearbox and an electric motor. The photovoltaic panel is pivotally connected in its middle part to the shaft and kinematically to the rotation mechanism. In the lower part the photovoltaic panel is pivotably connected by means of a pull rod to a cylindrical sleeve. On the contact surface of the shaft with the sleeve is made a sinusoidal channel, in which is placed a roller. The pull rod comprises a threaded sleeve, which on one side is connected to a threaded end of the pull rod, and on the other side the sleeve is connected to the opposite end of the rod by means of rollers
THE PEDIATRIC FLAT FOOT: PRE AND POST SURGICAL CORRECTION 3D KINEMATICS DATA
No full textIntroduction: aim of this study was to establish normality parameters and analyze 3D kinematic data before and after surgical correction of the pediatric flexible flat foot
Materials and methods: study population was composed of 2 groups: 10 children (20 feet, 5M/5F)without any disorders of the foot were evaluated to obtain normal reference data; 20 children with bilateral flexible flatfoot candidate to bilateral surgical correction (40 feet, 13M/7F) The RFM -3D kinematics protocol was used. Clinical, radiographic and instrumental evaluation were performed preoperatively and at 12 months by the same surgeon An arthroereisis of the subtalar joint was performed by the same surgeon. Patients were divided in 3 groups:1:normality;2:before surgery;3: after surgery. For all the variables and for the three planes of the space comparison between groups were performed.
Results: 3D rotational joint variables and planar angles were defined for normality, before and after sur-gery at the upright standing position. Differences were observed: hind foot , frontal plane; Chopart Joint ,transverse plane; Lisfanc Joint, frontal/transverse planes; ratio between 1rst and 2nd metatarsal, transverse plane; 2nd and 5th metatarsal versus ground respectively, sagittal plane; MLA, transverse plane
Discussion/conclusions:: different variables, normalized after correction, suggest that surgery performed at the hind foot can also improves mid foot pronation, increases the medial longitudinal arch and im-proves ratio between metatarsal bones, allowing to quantify changes that clinical and radiological evaluation cannot provide. The pediatric foot is similar to the adults and pediatric flexible flat foot could be corrected surgically, even if painless
PREVENTION OF HIP DISLOCATION IN CEREBRAL PALSY : EARLY MULTILEVEL MINIMALLY-INVASIVE APPROACH (E.M.M.A.)
No full textIntroduction
Hip problems in Cerebral Palsy are frequent (25-75%). Subluxation and dislocation of the hip is proportional to the neuromuscular involvement and is often due to the alterate spastic muscles forces acting on the femoral head in the acetabular cavity.
Aim: E.M.M.A approach (Early Multilevel Minimally-invasive Approach) has been designed in 3 different steps and applayed to decrease imbalanced forces due to spasticity acting on the femoral head and therefore to decrease hip migration progression, bone deformities and future pain with the minimal biological cost for the patients.
We consider age and R.I. as crucial discriminants for treatment steps.
All muscles around the hip joint are addressed simultaneously (dductor longus, ileopsoas, medial hamstrings and rectus femoris).
Material and method
E.M.M.A. 1: age 2 - 4 years, RI ≤ 20%: multilevel injection of botulinum toxin in case of muscular hyperactivity without morphological alterations of the couple muscle-tendon (contractures)
E.M.M.A 2: age 4 - 6 , RI ≥ 20%: multilevel aponeurectomies in case of muscular hyperactivity with morphological alterations of the couple muscle-tendon (retraction)
E.M.M.A. 3: AGE 6-8 EMMA 2 associated to early bone surgery (proximal femoral temporary epiphysiorisis with cannulated screw to achieve a progressive correction of valgus deformity).
We adopted this approach to prevent bone deformities with early mobilisation and early control of the pain in the same time
Result
In our department were treated 40 children with hip subluxation and a mean follow-up of 28 months. None of our patients have had a progression to reach hip dislocation.
Conclusion
E.M.M.A seems to be a practical and little invasive approach to achieve hip containment, decrease spasticity and also appears to be satisfactory to prevent progressive acetabular displasia and hip dislocation
Neopronematus Panou, Emmanouel and Kazmierski 2000
No full textGenus Neopronematus Panou, Emmanouel and Kaźmierski, 2000 Diagnosis. Setae h 2 and ps 2 absent. Tarsus III and IV with five setae. Trochanter I and II each with one seta. For more on the genus diagnosis see Panou et al. (2000)Published as part of Darbemamieh, Maryam, Hajiqanbar, Hamidreza, Khanjani, Mohammad & Kaźmierski, Andrzej, 2015, New species and records of Neopronematus (Acari: Iolinidae) from Iran with a key to world species, pp. 235-246 in Zootaxa 3990 (2) on page 236, DOI: 10.11646/zootaxa.3990.2.4, http://zenodo.org/record/23254
Postural and kinematic alterations in the paediatric asymptomatic plano-valgus foot joints
No full textINTRODUCTION: Plano-valgus (PV) is a common alteration of foot posture present in the paediatric population, characterized by valgus rearfoot, foot pronation and drop of the medial longitudinal arch (MLA). If misdiagnosed, this condition has the potential to cause pain and discomfort, and may hinder the lower limb kinematic chain. While a number of studies have investigated the kinematics of the paediatric PV foot, e.g. [1], no information is thus far available on postural and kinematic alterations of the major joints spanning the MLA - i.e. midtarsal and tarso-metatarsal.
METHODS: 20 children (13 M, 7 F; 13 ± 1 years) with bilateral asymptomatic PV foot were recruited in the study. Radiological indicators of PV condition, such as the calcaneal pitch, lateral talo-first metatarsal angle, and talo-navicular coverage, were measured from weight bearing X-rays. Gait analysis was conducted on the childrens’ feet with the Rizzoli Foot Model [2, 3]. This was applied to measuring double-leg support upright static posture and gait kinematics of the main foot joints, including midtarsal and tarso-metatarsal joints, along with MLA deformation. Range of motion and temporal
profiles of joint rotations were compared to those from a control group of age-matched children with normally-developed (ND) feet (4 M, 6 F; age 13 ± 1 years). Mann-Whitney U test was used to assess differences in static posture and kinematic global parameters between PV and control. One-dimensional statistical parametric mapping was used to determine differences in stance-normalized foot joint rotations between PV and control. Acknowledgement of the Hospital’s IRB was granted (protocol n° 7/17) and parents’ informed consent was obtained for all children recruited in the study.
RESULTS: The PV midtarsal joint was more dorsiflexed, everted and abducted than that in the control group, but showed reduced median sagittal-plane ROM (PV= 15.9 [12.1 19.2] deg; ND = 22.2 [19.5 24.9] deg; p < 0.01). The tarso-metatarsal joint was more plantarflexed and adducted, and showed larger frontal-plane ROM. The MLA showed larger ROM (PV= 58 ± 18 deg; ND = 37 ± 9 deg; p < 0.05) and was more dropped throughout gait duration. A diagrammatic representation of sagittal-plane orientation of foot segments in static posture and at push-off in stance is shown in figure 1.
DISCUSSION: Similar to what reported in previous studies, the PV hindfoot resulted significantly everted and plantarflexed with respect to the tibia, and the MLA was more collapsed throughout stance duration. In addition, the Rizzoli Foot Model allowed investigation of the postural and kinematic alterations at the midtarsal and tarso-metatarsal joints. It should be highlighted that children with PV foot walked more slowly and with a reduced stride length than control, and this might have– albeit marginally - affected the differences observed in the joint rotation profiles.
SIGNIFICANCE/CLINICAL RELEVANCE: In the paediatric plano-valgus foot, a hindered windlass mechanism and/or insufficient activation of the intrinsic plantar muscles [4] may be responsible for larger dorsiflexion of midfoot joints and greater collapse of the MLA during gait. A better understanding of PV midfoot joints postural and kinematic alterations is necessary to improve diagnosis and treatment of PV condition.
REFERENCES:
1. Hosl M, et al. Gait & Posture 2014; 39:23-8.
2. Leardini et al. Gait Posture 2007; 25(3):453-62
3. Portinaro et al. J Foot Ankle Res. 2014 20;7(1):754.
4. Angin S,et al. Gait & Posture, 2014; 40:48:52
Effect of plano-valgus foot posture on midfoot kinematics during barefoot walking in an adolescent population
No full textAbstract Background Plano-valgus is a common alteration of the paediatric foot, characterized by valgus hindfoot, foot pronation and drop of the medial longitudinal arch. Despite their importance in the diagnosis and classification of plano-valgus foot condition, little information is available on functional alterations of the major joints spanning the medial longitudinal arch – i.e. midtarsal and tarso-metatarsal. Aim of the study was to provide objective description of the alterations in plano-valgus midfoot joints with respect to those in an age-matched normally-developed feet population. Methods Twenty adolescents (13.3 ± 0.8 years) with bilateral plano-valgus feet underwent clinical examination and were gait-analysed via a validated 4-segment foot model. This allowed to measure static foot posture, kinematics of the main foot joints, and medial longitudinal arch deformation during walking at comfortable speed. Range of motion and temporal profiles of joint rotations were compared to those from a control population of age-matched adolescents with normally-developed feet. Results The plano-valgus midtarsal joint was more dorsiflexed, everted and abducted than that in the control group, and showed reduced sagittal-plane RoM (plano-valgus = 15.9 degrees; control = 22.2 degrees; P < 0.01). The tarso-metarsal joint was more plantarflexed and adducted, and showed larger frontal-plane RoM. The MLA showed larger RoM and was lower throughout the stance phase of the gait cycle. Conclusion Significant postural and kinematic alterations are present at the midtarsal and tarso-metarsal joints of adolescents with plano-valgus feet. Objective identification and quantification of plano-valgus foot alterations, via non-invasive gait-analysis, is relevant to improving the diagnosis of this condition and to evaluating the effect of conservative treatments and of surgical corrections by different techniques
Modifying the Rizzoli foot model to improve the diagnosis of pes-planus : application to kinematics of feet in teenagers
No full textBACKGROUND:
A number of multi-segment foot protocols have been proposed to obtain measurements of clinical value. In the clinical assessment of foot pathologies and deformities, such as in the pes-planus, the frontal-plane alignment of the calcaneus and the dynamic properties of the medial longitudinal arch are critical parameters though often neglected by the majority of foot protocols. The aim of the present work is to modify an established foot protocol to obtain static and kinematic measures more consistent with corresponding clinical observations. Moreover, while many papers have reported kinematic data from varying populations, few investigations have focussed on young participants from same-age cohorts.
METHODS:
A 6-camera motion capture system was employed to track the shank, rear-, mid- and fore-foot segments in the left and right leg of 10 children (13.1 ± 0.8 years) during gait. Three markers were attached to each segment thus allowing for triplanar motion of five joints to be described according to the Rizzoli Foot Model. An additional marker was attached to the posterior bottom of the calcaneus to enhance measurement of frontal-plane orientation. Description of the medial longitudinal arch angle was redefined to be more consistent with rearfoot orientation and to common clinical assessments. A novel 3-marker description of the hallux segment was implemented to improve robustness in calculating 1(st) metatarso-phalangeal joint rotations.
RESULTS:
Foot segments kinematics showed good inter- participant repeatability and overall consistency with previous similar reports. 15 out of 20 feet showed neutral or slightly valgus orientation of the calcaneus. Relatively large medial longitudinal arch angles (mean 186 ± 16 deg) were found in the present young population. Both measurements were reasonably in accordance with the relevant clinical observations of these feet.
CONCLUSIONS:
Modifications to a widely used multisegmental foot kinematic model were implemented to improve robustness and consistency with relevant clinical observations. A detailed description of foot joints motion during barefoot walking in a population of 13-year old children with apparent flat feet has been presented, which may provide useful information to investigate the development of gait in children and the diagnosis of flexible flat foot
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