ABSTRACT
BACKGROUND: Freezing of gait (FoG) is an episodic failure of gait exposing people with Parkinson's disease (PD) to a high risk of falling. Despite growing evidence of the interconnection between impaired trunk control and FoG, a detailed description of spinal kinematics during walking is still lacking in this population. RESEARCH QUESTION: Do spinal alterations impact gait performance in individuals with PD and FoG? METHODS: We analyzed kinematic data of 47 PD participants suffering (PD-FOG, N = 24) or not suffering from FoG (PD-NFOG, N = 23) and 15 healthy controls (HCO) during quiet standing and unperturbed walking. We estimated the main spinal variables (i.e., spinal length, lordosis and kyphosis angles, trunk inclination), the pelvis angles, and the shoulder-pelvis angles during gait and standing. We studied differences across conditions and groups and the relationships between postural and gait parameters using linear regression methods. RESULTS: During standing and walking, both PD groups showed increased trunk inclination and decreased lordosis angle with respect to HCO, as well as a decreased range in variation of kyphosis angle, pelvic obliquity, and shoulder-pelvis angles. Only PD-FOG participants showed reduced range of lordosis angle and spinal length compared to HCO. PD-FOG individuals were also not able to straighten their spine during walking compared to standing. Stride length and velocity were decreased in both patient groups compared to HCO, while swing duration was reduced only in the PD-FOG group. In individuals with FoG, trunk inclination and lordosis angle showed moderate but significant positive correlations with all gait alterations. SIGNIFICANCE: Spine alterations impacted gait performance in individuals with PD suffering from FoG. Excessive trunk inclination and poor mastering of the lordosis spinal region may create an unfavourable postural precondition for forward walking. Physical therapy should target combined spinal and stepping alterations in these individuals.
Subject(s)
Gait Disorders, Neurologic , Kyphosis , Lordosis , Parkinson Disease , Humans , Parkinson Disease/complications , Parkinson Disease/therapy , Biomechanical Phenomena , Gait Disorders, Neurologic/etiology , Gait , WalkingABSTRACT
This paper is a study of surface effects, e.g. roughness or asymmetrical cut, in the Laue diffraction of X-rays by crystals, based on the Takagi-Taupin equations. By means of Riemann-Green integrals, first a formal solution has been obtained when the entrance and the exit surfaces are arbitrary. Then a coordinate transformation mapping a propagation domain with arbitrary boundaries into a rectangular domain with straight boundaries is given. Potential measurement errors in \gamma-ray wavelength and silicon lattice-parameter measurements by double-crystal diffractometry and X-ray interferometry, respectively, are outlined and anticipated by studying, in the two-wave approximation, the reflection peak shift and extra phase originating from an asymmetrically cut crystal. A relationship between analyser displacement, interferometer-signal phase and relative uncertainty in lattice-parameter measurement is also given.
ABSTRACT
In this paper, X-ray and gamma-ray propagation in crystals having a constant strain gradient and flat or cylindrical surfaces is investigated. When a displacement field is present, the Takagi-Taupin equations are solved either by the Riemann-Green method or by a numerical method. The results are applied to study the operation of a double-crystal Laue-Laue diffractometer having a flat collimating crystal followed by a bent analyzer crystal. In particular, the effect of the analyzer strain on the location of the diffraction peaks in the dispersive and non-dispersive set-up is examined, thus confirming the previously reported peak location as being set only by the diffracting-plane spacing on the analyzer entrance surface.
Subject(s)
Crystallization , Gamma Rays , X-Rays , Models, Theoretical , Surface PropertiesABSTRACT
This document describes the results of collaborative trials between St. Tammany Parish Mosquito Control, ADAPCO, Inc., and the Navy Disease Vector Ecology and Control Center, Naval Air Station, Jacksonville, FL. These tests provide data on the aerial optimization testing of Dibrom 14 Concentrate adulticide. During the week of June 17, 2002, 1 canopy penetration and 3 optimization studies were conducted in St. Tammany Parish, LA, using a Britton Norman twin turbine Islander equipped with 10-800067 flat fan nozzles. Dibrom 14 Concentrate (AMVAC Chemical Corp., Los Angeles, CA) was applied at 3.12 liter per min from a release height of 60.96 m above ground level (agl) at 140 kts indicated airspeed. This resulted in an application rate of 0.65 oz/acre.
Subject(s)
Insecticides , Mosquito Control/methods , Naled , Aircraft , Louisiana , TreesABSTRACT
We describe the interaction of the neodymium: yttrium aluminum garnet (Nd:YAG) laser energy with intraocular lenses using the laser in the Q-switched mode. Using this method, it is possible to treat opacities that eventually might occur at the level of the visual axis on the optic faces of polymethylmethacrylate intraocular lenses (IOLs) if safety parameters (perfect focusing, use of additional lenses, and slight and continuous movement of the focal point of the laser) are followed. However, it is not possible to treat the silicone IOLs with the Nd:YAG laser because the threshold values for damage to the IOL are lower than the energy values required for destroying the capsular opacities on the optic axis.
Subject(s)
Cataract Extraction/methods , Laser Therapy/methods , Lenses, Intraocular , Animals , Disease Models, Animal , Lens Capsule, Crystalline/surgery , Methylmethacrylates , RabbitsABSTRACT
Using a multimode and a fundamental mode Q-switched Nd-YAG laser, the authors study the possible damages to glass and PMMA IOLs in vitro. The fundamental parameters in this evaluation seem to be the distance between the focus and the IOL and the power delivered.
Subject(s)
Cataract Extraction/instrumentation , Laser Therapy/instrumentation , Lenses, Intraocular , Glass , Humans , Methylmethacrylates , Suture TechniquesSubject(s)
Cataract/pathology , Lead/analysis , Lens, Crystalline/analysis , Cadmium/analysis , Copper/analysis , Humans , MethodsABSTRACT
The authors report a case of pigmented cysts of the iris, observed in female subjects of the same family and of three generations. They hypothesize that it may be due to a hereditary alteration connected to sex, and believe it should be considered as a mesodermal alteration, occurring during embryonic development. The treatment has been para-surgical by means of a Nd-YAG laser, operating in a free-running mode, with impulses directed onto the cysts.
Subject(s)
Cysts/genetics , Iris Diseases/genetics , Adult , Cysts/surgery , Female , Humans , Iris Diseases/surgery , Karyotyping , Laser Therapy , PedigreeABSTRACT
The authors reported a culturally proven case of orbital cellulitis, uveitis and conjunctivitis due to Yersinia enterocolitica serotype 0:9. This case, in addition to the previously reported, remarks the importance of Yersinia enterocolitica as ocular pathogen.
