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Biomedical subjects

H Liu

Publications and source records attributed to H Liu.

At least 1,243 records · Page 69Linked to original sources
PubMed1981

Objective pathological diagnosis of coal worker's pneumoconiosis.

Pertinent pathological features of lungs obtained at autopsies from 99 coal miners were compared with those observed in the lungs of 268 male town dwellers of comparable age who were not occupationally related to the coal mining or other industries at risk for development of pneumoconiosis. The degree of anthracotic pigment deposition and severity of type of pigmented lesion with its accompanying reticulum fiber formation and fibrosis were significantly greater in lungs of miners. There was a high degree of overlap in degree of pigment deposition, particularly those quantitated as grades 1 and 2 and in lesions regarded as types 1 and 2. The greatest divergence was observed for prevalence of nodular pulmonary lesions (type 4). There was also a considerable divergence in the type 3 alteration characterized by nonnodular aggregates of carbon-laden macrophages accompanied by minimal reactive fibrosis. It appears that an objective pathological diagnosis of coal workers' pneumoconiosis (CWP) can be rendered only by the demonstration of type 4 lesions. Approximately 25% of coal miners exhibited unequivocal features of CWP. No significant differences concerning incidence or types of emphysema or frequency of chronic cor pulmonale were encountered between the two populations.

Adult↗
PubMed1980

Correlation of estrogen receptor and pathologic characteristics of invasive breast cancer.

Estrogen receptor (ER) status was correlated with a large number of pathological and clinical characteristics of 178 invasive breast cancers. Positive ER was found to be significantly associated with high nuclear and low histologic grades, absence of tumor necrosis, presence of marked tumor elastosis, and older patients. These pathologic parameters enumerated are either directly or indirectly related to tumor differentiation suggesting that ER represents another index of this latter. Multivariate analyses disclosed that both age and tumor differentiation are associated with the ER status. Well-differentiated tumors were more frequently ER+ in older women. Inclusion of an estimate of tumor necrosis as well as patient age appears to allow for further discrimination of ER status in poorly differentiated lesions. Considerations relative to ER and tumor differentiation provide a possible explanation for the dichotomy of response to adjuvant chemotherapy observed in pre and postmenopausal women.

Adult↗
PubMed1975

Vitreous surgery. XII. New instrumentation for vitrectomy.

An improved instrument for removing vitreous tissue consists of a replaceable cutting tip and a micromotor that powers the cutting tip. The cutting tip consists of a helical cutter and a metallic tube housing the cutter. An automated power-control unit is also available to control evacuation, infusion, and speed of rotation of the instrument. Several devices for monitoring the outflow of evacuation material and pressure in the eye and in the evacuation line are included. The cutting tip is illuminated by a fiber-optic system, which provides an additional factor of safety. The instrument contains a cleaning mechanism that eliminates the need for disassembling the cutting tip. When an automated control unit is not available, the vitreous nibbler may be used with manual suction, gravity-controlled infusion, and a simplified control unit.

Automation↗
PubMedDate not supplied

An empirical evaluation of various priors in the empirical Bayes estimation of small area disease risks.

Empirical and fully Bayes estimation of small area disease risks places a prior distribution on area-specific risks. Several forms of priors have been used for this purpose including gamma, log-normal and non-parametric priors. Spatial correlation among area-specific risks can be incorporated in log-normal priors using Gaussian Markov random fields or other models of spatial dependence. However, the criterion for choosing one prior over others has been mostly logical reasoning. In this paper, we evaluate empirically the various priors used in the empirical Bayes estimation of small area disease risks. We utilize a Spanish mortality data set of a 12-year period to give the underlying true risks, and estimate the true risks using only a 3-year portion of the data set. Empirical Bayes estimates are shown to have substantially smaller mean squared errors than Poisson likelihood-based estimates. However, relative performances of various priors differ across a variety of mortality outcomes considered. In general, the non-parametric prior provides good estimates for lower-risk areas, while spatial priors provide good estimates for higher-risk areas. Ad hoc composite estimates averaging the estimates from the non-parametric prior and those from a spatial log-normal prior appear to perform well overall. This suggests that an empirical Bayes prior that strikes a balance between these two priors, if one can construct such a prior, may prove to be useful for the estimation of small area disease risks.

Adult↗
PubMedDate not supplied

Interventional MRI at high-field (1.5 T): needle artifacts.

A better understanding of the appearance of a biopsy needle as well as its interaction with various sequence parameters in MRI is beneficial for its application in interventional MRI. As an extension of previous researchers' contributions, we investigate the specific characteristics of MR image artifacts associated with the tip of a biopsy needle when it is approximately parallel to the main magnetic field. The origin of the needle tip artifact, which exhibits as a blooming ball, was studied using MRI techniques and numerical simulation using the finite element method (FEM). Satisfactory agreement between theory and experiment has been achieved. Results showed that the image artifacts associated with biopsy needle are present and dependent on imaging parameters, but the artifacts can be reduced if optimal imaging parameters were used. Images of actual human brain tumor biopsies performed using the same needle under MRI guidance and monitoring demonstrated this artifact.

Artifacts↗
PubMedDate not supplied

Estimation of turbulent shear stress in free jets: application to valvular regurgitation.

In an attempt to better assess the severity of valvular regurgitation, an in-vitro experiment has been conducted to estimate turbulent shear stress levels within free jets issuing from different orifice shapes and sizes by means of hot-wire anemometry. On the basis of the measured mean velocities and the jet profiles, the distributions of the normalized kinematic turbulent shear stress (uv/Um2) were estimated for different jets by using an equation available for self-preserving circular jet. The results indicate that the equation can estimate the distributions of uv/Um2 independent of the orifice shape and Reynolds number of the jet. For the range of Reynolds numbers considered, the estimation of maximum turbulent shear stress inferred from these distributions suggests that the critical shear stress level of approximately 200 N/m2, corresponding to destruction of blood cells, is exceeded for typical blood flow velocity of 5 m/s at the valvular lesion.

Blood Flow Velocity↗
PubMedDate not supplied

Immobilization of glucose oxidase with the blend of regenerated silk fibroin and poly(vinyl alcohol) and its application to a 1,1'-dimethylferrocene-mediating glucose sensor.

The structure and properties of the blend of regenerated silk fibroin (RSF) and poly(vinyl alcohol) (PVA) were investigated. The two polymers in the blend are in the state of phase segregation. Infrared (IR) spectra indicate that the RSF in the blend maintains its intrinsic properties, thus, ethanol treatment can transfer silk I structure of RSF to silk II structure. The water absorption property and mechanical property of the blend are improved in comparison with those of RSF. The blend maintains the major merit of RSF, that is, it can immobilize glucose oxidase on the basis of the conformational transition from silk I structure to silk II structure. The properties of the immobilized enzyme are examined. Moreover, the second generation of glucose sensor based on the immobilized enzyme is fabricated and it has a variety of advantages including easy maintenance of enzyme, simplicity of construction, fast response time and high stability.

Biosensing Techniques↗