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J H Gardner

Publications and source records attributed to J H Gardner.

15 recordsLinked to original sources
PubMed2006

Size distribution and energy spectrum in the mixed state induced by Rayleigh-Taylor instability.

A study--based on simulations and experiments as well as analytical derivations--of the internal structure of the fragmented ("mixed") state induced by the Rayleigh-Taylor instability at the interface between two fluids is presented. The distribution of sizes and the energy spectrum in the fragmented state are derived from the symmetries exhibited by the data and by dimensional analysis.

Journal Article↗
PubMed2001

Direct observation of mass oscillations due to ablative Richtmyer-Meshkov instability in plastic targets.

We report the first direct experimental observation of the ablative Richtmyer-Meshkov instability. It manifests itself in oscillations of areal mass that occur during the shock transit time, which are caused by the "rocket effect" or dynamic overpressure characteristic of interaction between the laser absorption zone and the ablation front. With the 4-ns-long Nike KrF laser pulse and our novel diagnostic technique (monochromatic x-ray imaging coupled to a streak camera) we were able to register a peak and a valley of the areal-mass variation before the observed onset of the Rayleigh-Taylor growth.

Journal Article↗
PubMed2001

Direct observation of feedout-related mass oscillations in plastic targets.

"Feedout" means the transfer of mass perturbations from the rear to the front surface of a driven target. When a planar shock wave breaks out at a rippled rear surface of the target, a lateral pressure gradient drives sonic waves in a rippled rarefaction wave propagating back to the front surface. This process redistributes mass in the volume of the target, forming the feedout-generated seed for ablative Rayleigh-Taylor (RT) instability. We report the first direct experimental observation of areal-mass oscillation associated with feedout, followed by the onset of exponential RT growth.

Journal Article↗
PubMed1991

Warfarin skin necrosis: recurrence in the absence of anticoagulant therapy.

Skin necrosis is a well-known yet rare complication of oral anticoagulant therapy. We report the unusual recurrence of lesions typical of warfarin skin necrosis in the absence of anticoagulant therapy. A 59-year-old woman developed skin necrosis while receiving prophylactic warfarin following the detection of a large left ventricular thrombus. The warfarin was discontinued and the lesions improved. One month later new areas of skin necrosis developed although the patient had received no further warfarin. Progressive congestive heart failure, poor nutrition, and prolonged oral antibiotic therapy preceded the recurrence. Vitamin K deficiency was present on admission. The potential role of vitamin K-dependent coagulation factors in the pathogenesis of anticoagulant-associated skin necrosis is discussed.

Female↗
PubMed1981

Carcinoma of sebaceous glands on the head and neck. A report of four cases.

Carcinoma of sebaceous glands most commonly occurs on the eyelids and caruncles of the elderly. Local recurrences after would-be adequate treatment and distant metastases are common in this malignancy in this site. Carcinomas of sebaceous glands arising elsewhere in the skin also have a strong tendency to recur locally, but are said to be much less likely to metastasize. Our experience with four such carcinomas on the head and neck have led us to believe that the malignancy is biologically aggressive anywhere if not adequately treated at the onset.

Aged↗
PubMed1981

Intrachiasmatic arteriovenous malformation. Case report.

A patient presented with an abrupt monocular decrease in visual acuity and a bitemporal hemianopsia. At surgery, a totally intrachiasmatic arteriovenous malformation was removed, with subsequent resolution of the visual deficit.

Adult↗
PubMed1977

Enzymic reactions of phosphate analogs.

A variety of phosphonates (XPO32-; X = H-, CH3-, CL3C-, CH3CH2-, and phenyl-) as well as methylarsonate have been shown to be suitable phosphate analogs for the reactions catalyzed by yeast glyceraldehyde-3-phosphate dehydrogenase and calf spleen purine nucleoside phosphorylase. The reactivity of the phosphate analogs with these two enzymes is independent of the pKa of the analog.

Animals↗
PubMed1977

Development of cleavage line patterns in the human fetus.

The dermal fibroelastic connective tissue of the fetus is arranged in such a manner as to represent cleavage lines (lines of tension). Cleavage lines were observed as early as the 28 mm stage but in most cases they do not appear until the 50 mm stage. The various regions of the body present individual cleavage line patterns which undergo alterations as the fetus grows. The pattern alterations are influenced by (1) rate of proportional growth and (2) principal direction of growth of certain structures in the various regions. The cleavage line pattern of the newborn differs from that of the adult in certain regions.

Connective Tissue↗
PubMedDate not supplied

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