On-treatment predictions of success in peg-interferon/ribavirin treatment using a novel formula

AIM:To predict treatment success using only simple clinical data from peg-interferon plus ribavirin therapy for chronic hepatitis C. METHODS:We analyzed the clinical data of 176 patients with chronic hepatitis and hepatitis C virus genotype 1 who received 48 wk standard therapy, derived a predictive formula to assess a sustained virological response of the individual patient using a logistic regression model and confirmed the validity of this formula.The formula was constructed using data from the first 100 patients enrolled and validated using data from the remaining 76 patients. RESULTS:Sustained virological response was obtained in 83(47.2%)of the patients and we derived formulae to predict sustained virological response at pretreatment and weeks 4,12 and 24.The likelihood of sustained virological response could be predicted effectively bythe formulae at weeks 4,12 and 24(the area under the curve of the receiver operating characteristic:0.821, 0.802,and 0.891,respectively),but not at baseline (0.570).The formula at week 48 was also constructed and validation by test data achieved good prediction with 0.871 of the area under the curve of the receiver operating characteristic.Prediction by this formula was always superior to that by viral kinetics. CONCLUSION:These results suggested that our formula combined with viral kinetics provides a clear direction of therapy for each patient and enables the best tailored treatment.

Numerical Analysis of Cold-Formed Thin-Walled Steel Short Columns with Pitting Corrosion during Bridge Construction

Pitting corrosion is harmful during bridge construction,which will lead to uneven roughness of steel surfaces and reduce the thickness of steel.Hence,the effect of pitting corrosion on the mechanical properties of cold-formed thin-walled steel stub columns is studied,and the empirical formulas are established through regression fitting to predict the ultimate load of web and flange under pitting corrosion.In detail,the failure modes and load-displacement curves of specimens with different locations,area ratios,and depths are obtained through a large number of non-linear finite element analysis.As for the specimens with pitting corrosion on the web,all the specimens are subject to local buckling failure,and the failure mode will not change with pitting corrosion,but the failure location will change with pitting corrosion location;the size,location,and area ratio of pitting corrosion have little influence on the ultimate load of cold-formed thin-walled steel short columns,but the loss rate of pitting corrosion section area has a greater impact on the ultimate bearing capacity.As for the specimen with flange pitting corrosion,the location and area ratio of pitting corrosion have less influence on the ultimate load of cold-formed thin-walled steel short columns,and the section area loss rate has greater influence on the ultimate bearing capacity;the impact of web pitting corrosion on the ultimate load is greater than that of flange pitting corrosion under the same condition of pitting corrosion section area.The prediction formulas of limit load which are suitable for pitting corrosion of web and flange are established,which can provide a reference for performance evaluation of corroded cold-formed thin-walled steel.

Prediction Method of Seismic Residual Deformation of Caisson Quay Wall in Liquefied Foundation

The multi-spring shear mechanism plastic model in this paper is defined in strain space to simulate pore pressure generation and development in sands under cyclic loading and undrained conditions, and the rotation of principal stresses can also be simulated by the model with cyclic behavior of anisotropic consolidated sands. Seismic residual deformations of typical caisson quay walls under different engineering situations are analyzed in detail by the plastic model, and then an index of liquefaction extent is applied to describe the regularity of seismic residual deformation of caisson quay wall top under different engineering situations. Some correlated prediction formulas are derived from the results of regression analysis between seismic residual deformation of quay wall top and extent of liquefaction in the relative safety backfill sand site. Finally, the rationality and the reliability of the prediction methods are validated by test results of a 120 g-centrifuge shaking table, and the comparisons show that some reliable seismic residual deformation of caisson quay can be predicted by appropriate prediction formulas and appropriate index of liquefaction extent.

Experimental Study of Irregular Wave Reflection by a Perforated Caisson Breakwater Under Wave Overtopping Conditions

The characteristics of irregular wave reflection by a perforated caisson breakwater under wave overtopping conditions were investigated using physical model tests.The effects of various parameters,especially the mean overtopping discharge that was mainly determined by the relative crest freeboard,on the reflection coefficient of perforated caisson breakwater were analyzed using experimental data.The results showed that the wave overtopping occurrence had no appreciable effect on the reflection coefficient when the mean overtopping discharge was less than 0.2 m^(3)(m s)^(−1).Under the wave overtopping condition,the reflection coefficient of the perforated caisson breakwater in this study was reduced by 20%-50% compared with that of the non-perforated caisson breakwater.A predictive formula of the reflection coefficient for perforated caisson breakwaters in terms of relative water depth,relative chamber width,and porosity of the caisson front wall,was developed for practical engineering design.

Corona Onset Voltage Gradient of Bundle Conductors for EHV/UHV AC Power Lines in Corona Cages Considering Altitude Correction

The corona onset voltage gradient(COG)of conductors is a key parameter in the design of overhead transmission lines.The commonly used semi-empirical calculation formula proposed by Peek(1910s)at present can roughly estimate the COG of single conductors and is not applicable to large cross-section bundle conductors.In this paper,experiments are conducted to investigate the corona characteristics of a whole series of bundle conductors at different altitudes,and a prediction formula is proposed for the COG of large cross-section bundle conductors on AC transmission lines considering the altitude correction.The calculated values using the proposed prediction formula are compared with the experimental values of the COG in two cases:UHV eight-bundle conductors at an altitude of 19 m;500 kV UHV four-bundle conductors in Wuhan,Xining,Geermu,and Nachitai at four different altitudes.The results show that the use of the formula can predict the COG of bundle conductors with the radius of 1.34 cm to 1.995 cm and the number of subconductors of 4 to 12 at altitudes of 19 m to 4000 m above the mean sea level.The research findings can provide a reference for the design of EHV and UHV overhead transmission lines and even those in higher voltage levels.