The aberrant nonspherical portion of the femoral head in young patients with an impingement conflict consists of hyaline cartilage which shows clear degenerative signs similar to the findings in osteoarthritic cartilage. The tissue alterations are distinctly different when compared with a control group, which substantiates an impingement conflict as an early mechanism for degeneration at the hip joint periphery.
The reactions of hydroxyl radicals with eight substituted aromatic hydrocarbons and four olefins were studied utilizing the flash photolysis-resonance fluorescence technique. The rate constants were measured at 298°K using either Ar or He as the diluent gas. The values of the rate constants (k X 10l2) in the units of cm3/molec. sec are
Patients with peripheral arterial disease (PAD) may develop a broad range of peripheral nerve dysfunctions including pain and sensory deficiencies due to chronic ischemia mostly involving the lower limbs. To investigate the degree of sensory abnormalities in such patients quantitative sensory testing (QST) might be a useful tool. Forty-five patients and 20 controls were enrolled in the present study and underwent QST according to the protocol of the German Research Network on Neuropathic Pain. PAD was graded according to the Rutherford classification. PAD patients were divided into two groups: 16 patients with critical limb ischemia (severe PAD) and 29 patients with intermittent claudication (moderate PAD). QST revealed impaired cold and warm detection, increased mechanical and vibration detection thresholds, and increased perceptual wind-up on the affected leg (all p<0.001). Paradoxical heat sensation (p<0.05) and dynamic mechanical allodynia (p<0.01) were also observed. Subgroup analysis of patients without diabetes (control n=20, moderate PAD n=21, severe PAD n=8) confirmed most of these findings. In patients with severe PAD, sensory deficits were more pronounced than in patients with moderate PAD and were detected even in the face. These data indicate that QST can detect sensory abnormalities in PAD patients. While the pattern of decreased perception suggests deafferentation for Abeta-, Adelta-, and C-fiber inputs, the presence of allodynia suggests that central sensitization also plays a role in the pain state of PAD patients. Subgroup analysis points towards a PAD-associated peripheral neuropathy independent of diabetes.
The flash photolysis resonance fluorescence technique has been utilized to determine the Arrhenius parameters for several reactions between the hydroxyl radical and halogenated hydrocarbons. The reactions studied, and their corresponding Arrhenius expressions in units of cm3 molecule™1 s 1 are shown: (1) OH + CH2C1F -CHC1F + H20, ki = (2.84 ± 0.3) X 10™12 exp(-(1259 ± 50)/T) K; (2) OH + CHC12F -CC12F + H20, k2 = (1.87 ± 0.2) X 10 12 exp(-(1245 ± 26)/T) (245-375) K; (3) OH + CHC1F2 -» CC1F2 + H20, k3 = (9.25 ± 1.0) X 10™13 exp(-(1575 ± 71 )/T) (250-350) K; (4) OH + CH3CCI3 -CH2CC13 + H20, fc4 = (3.72 ± 0.4) X 10™12 exp(-(1627 ± 50)/T) (260-375) K; (5) OH + CH3CF2C1 -> CH2CF2C1 + H20, h = (1.15 ± 0.15) X 10™12 exp(-(1748 ± 30)/T) (273-375) K; (6) OH + CF2C1CFC12 -products, k6 < 3 X 10 16. Tropospheric lifetimes have been calculated for the above species by combining the rate constant data with global seasonally and diurnally averaged hydroxyl radical concentrations.
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