PubMed Health⌕ Search

Biomedical subjects

T Lay

Publications and source records attributed to T Lay.

7 recordsLinked to original sources
PubMed2005

Deep mantle structure and the postperovskite phase transition.

Seismologists have known for many years that the lowermost mantle of the Earth is complex. Models based on observed seismic phases sampling this region include relatively sharp horizontal discontinuities with strong zones of anisotropy, nearly vertical contrasts in structure, and small pockets of ultralow velocity zones (ULVZs). This diversity of structures is beginning to be understood in terms of geodynamics and mineral physics, with dense partial melts causing the ULVZs and a postperovskite solid-solid phase transition producing regional layering, with the possibility of large-scale variations in chemistry. This strong heterogeneity has significant implications on heat transport out of core, the evolution of the magnetic field, and magnetic field polarity reversals.

Journal Article↗
PubMed2000

Mantle dynamics and seismic tomography.

Three-dimensional imaging of the Earth's interior, called seismic tomography, has achieved breakthrough advances in the last two decades, revealing fundamental geodynamical processes throughout the Earth's mantle and core. Convective circulation of the entire mantle is taking place, with subducted oceanic lithosphere sinking into the lower mantle, overcoming the resistance to penetration provided by the phase boundary near 650-km depth that separates the upper and lower mantle. The boundary layer at the base of the mantle has been revealed to have complex structure, involving local stratification, extensive structural anisotropy, and massive regions of partial melt. The Earth's high Rayleigh number convective regime now is recognized to be much more interesting and complex than suggested by textbook cartoons, and continued advances in seismic tomography, geodynamical modeling, and high-pressure-high-temperature mineral physics will be needed to fully quantify the complex dynamics of our planet's interior.

Journal Article↗
PubMed1998

Variation of interplate fault zone properties with depth in the japan subduction zone

The depth dependence of physical properties along the Japan subduction zone interface was explored using teleseismic recordings of earthquake signals. Broadband body waves were inverted to determine the duration of rupture and source depth for 40 interplate thrust earthquakes located offshore of Honshu between 1989 and 1995. After scaling for differences in seismic moment, there is a systematic decrease in rupture duration with increasing depth along the subducting plate interface. This indicates increases in rupture velocity or stress drop with depth, likely related to variation in rigidity of sediments on the megathrust.

Journal Article↗
PubMed1997

Use of azathioprine for nongranulomatous ulcerative jejunoileitis.

Nongranulomatous ulcerative jejunoileitis (NGUJI) is a rare, often fatal disorder that produces multiple nonmalignant small bowel ulcerations. A 55-year-old woman with presumed celiac disease presented with steroid-refractory diarrhea, weight loss and abdominal pain. A laparotomy was performed to exclude the possibility of a lymphomatous disorder, and multiple nonmalignant small bowel ulcerations were discovered. Despite a combination of treatment with total parenteral nutrition (TPN) and prednisone 30 mg/day she continued to deteriorate. The addition of azathioprine to her treatment regimen resulted in marked clinical and biochemical improvement. Her enteroscopy normalized, and she was able to discontinue TPN and reduce her steroid requirements. Although azathioprine has been used occasionally to treat refractory sprue, there have been no reports of its use in NGUJI. In this case, azathioprine played a key role in the management of NGUJI and should be considered a treatment option for patients with this disorder.

Azathioprine↗
PubMed1994

The flourishing problem of elder abuse in our society.

The increasing maturation of our population and the economic hardships in our nation have forced numerous elders to become dependent upon family members for survival. The tremendous strain of providing care for a dependent elder along with societal demands has caused the problem of elder abuse to flourish. Frequently, emergency rooms and intensive care units are the primary points of entry for the elderly victim of abuse. It is within these settings that abuse is detected initially and in which successful intervention should begin. In this article, the author presents a review of the basic theories that have been proposed to explain why abuse occurs. This is followed by a detailed description of the common characteristics of both the abuser and the abused. The article is concluded by an overview of the medical personnel's responsibilities for reporting cases of suspected abuse.

Aged↗
PubMedDate not supplied

Comorbid anxiety and affective disorder in alcohol-dependent patients seeking treatment: the first Multicentre Study in Germany.

The goals of this study were to describe demographic variables, drinking history, and the 6-month prevalence of Axis I comorbidity among alcohol-dependent subjects in GERMANY: The variables: amount of alcohol consumption, age at onset of the first alcohol consumed, age at onset of daily alcohol consumption, age at onset of withdrawal symptoms and number of detoxifications were related to the different comorbid disorders and gender. In this study, 556 patients from 25 alcohol treatment centres were enrolled between 1 January 1999 and 30 April 1999. After a minimum of 10 days of sobriety patients who fulfilled ICD-10 and DSM-IV criteria of alcohol dependence were interviewed for data collection using the Mini-DIPS (German version of the Anxiety Disorders Interview Schedule) and a standardized psychosocial interview. The 6-month prevalence of comorbid Axis I disorders was 53.1%. Among the patients with comorbidity, affective and anxiety disorders were most frequent. Comorbid stress disorder was associated with an early start of drinking, an early beginning of withdrawal symptoms, highest number of detoxifications, and the highest amount of alcohol consumed. Female patients with anxiety disorder consumed more alcohol and started earlier than females without this comorbid disorder. The data do not answer the question of the pathogenesis of comorbid disorders and alcoholism, but indicate that stress disorders in alcoholic patients and anxiety disorders in female alcoholics influence the course and severity of alcoholism.

Adult↗