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Zhen Ye

Publications and source records attributed to Zhen Ye.

At least 19 recordsLinked to original sources
PubMed2026

Age-stratified associations of glycemia, blood pressure, and cholesterol with mortality in diabetes: A prospective cohort study.

BACKGROUND: Optimization of HbA1c, blood pressure and cholesterol, referred to as the "ABCs", is central to the management of diabetes. However, the age-specific associations of these factors with mortality in patients with diabetes remains unclear. METHODS: In this prospective cohort study, 43,732 Chinese adults aged&#x2009;&#x2265;&#x2009;40 years with diabetes were included from the China Cardiometabolic Disease and Cancer Cohort (4C) Study. Participants were stratified by age (<&#x2009;55, 55-<65, 65-<75, &#x2265;&#x2009;75 years). Cox proportional hazards regression and Fine-Gray competing risk models were employed to estimate the associations of HbA1c, systolic blood pressure (SBP), and low-density lipoprotein cholesterol (LDL-C) with all-cause, cardiovascular, and non-cardiovascular mortality across age groups. Relative importance and population attributable fractions (PAFs) were computed for each metabolic factor. RESULTS: During a median follow-up of 10.1 years, 3,975 deaths were documented. Age significantly modified the associations of HbA1c, SBP, and LDL-C with all mortality outcomes (all P for interaction&#x2009;<&#x2009;0.05). Among participants aged&#x2009;<&#x2009;75 years, HbA1c showed graded positive associations with all-cause, cardiovascular, and non-cardiovascular mortality. The SBP thresholds associated with increased mortality risk were 140 mmHg in those aged&#x2009;<&#x2009;65 years and 160 mmHg in those aged 65-<75 years. Among those aged&#x2009;&#x2265;&#x2009;75 years, however, the patterns of these associations differed markedly. Elevated mortality risk was observed only at HbA1c&#x2009;&#x2265;&#x2009;9%, with a hazard ratio (HR) of 1.51 (95% confidence interval [CI]: 1.19-1.91) for all-cause mortality and a subdistribution hazard ratio (SHR) of 1.70 (95% CI: 1.23-2.36) for cardiovascular mortality, while SBP showed no significant association with any mortality outcome in this age group. Moreover, LDL-C emerged as a significant risk factor for cardiovascular mortality. Compared with participants with LDL-C&#x2009;<&#x2009;1.8 mmol/L, those with LDL-C of 1.8-<2.6 mmol/L exhibited a significantly higher risk (SHR: 1.86; 95% CI: 1.11-3.11). Additionally, LDL-C had the largest PAF for cardiovascular mortality (9.6%) within this age group. CONCLUSIONS: The impacts of ABC factors on mortality risk vary substantially by age among adults with diabetes. In patients aged&#x2009;&#x2265;&#x2009;75 years, less stringent glycemic and blood pressure targets may be appropriate, whereas lipid management remains critically important for reducing cardiovascular mortality.

Humans↗
PubMed2005

ASF/SF2-regulated CaMKIIdelta alternative splicing temporally reprograms excitation-contraction coupling in cardiac muscle.

The transition from juvenile to adult life is accompanied by programmed remodeling in many tissues and organs, which is key for organisms to adapt to the demand of the environment. Here we report a novel regulated alternative splicing program that is crucial for postnatnal heart remodeling in the mouse. We identify the essential splicing factor ASF/SF2 as a key component of the program, regulating a restricted set of tissue-specific alternative splicing events during heart remodeling. Cardiomyocytes deficient in ASF/SF2 display an unexpected hypercontraction phenotype due to a defect in postnatal splicing switch of the Ca(2+)/calmodulin-dependent kinase IIdelta (CaMKIIdelta) transcript. This failure results in mistargeting of the kinase to sarcolemmal membranes, causing severe excitation-contraction coupling defects. Our results validate ASF/SF2 as a fundamental splicing regulator in the reprogramming pathway and reveal the central contribution of ASF/SF2-regulated CaMKIIdelta alternative splicing to functional remodeling in developing heart.

Alternative Splicing↗
PubMed2005

Gravity waves over topographical bottoms: comparison with experiment.

The propagation of water surface waves over one-dimensional periodic and random bottoms is investigated by the transfer matrix method. For the periodic bottoms, the band structure is calculated, and the results are compared to the transmission results. When the bottoms are randomized, the Anderson localization phenomenon is observed. The theory has been applied to an existing experiment [J. Fluid Mech. 186, 539 (1988)]]. In general, the results are compared favorably with the experimental observation.

Journal Article↗
PubMed2004

Optical transmission of photonic crystal structures formed by dielectric cylinders: evidence for non-negative refraction.

By a rigorous numerical simulation based on the standard multiple scattering theory, we investigate optical transmission in photonic crystal structures, formed from dielectric cylinders embedded in parallel in a uniform medium. In contrast to previous conjectures, the results indicate that the imaging effect of a flat photonic crystal slab, which has been interpreted as a signature of negative refractive effects, is caused by a tunneling or self-guiding effect in the presence of partial band gaps.

Journal Article↗
PubMed2004

Electromagnetic energy and energy flows in photonic crystals made of arrays of parallel dielectric cylinders.

We consider electromagnetic propagation in two-dimensional photonic crystals, formed by parallel dielectric cylinders embedded a uniform medium. The frequency band structure is computed using the standard plane-wave expansion method, and the corresponding eigenmodes are obtained subsequently. The optical flows of the eigenmodes are calculated by a direct computation approach, and several averaging schemes of the energy current are discussed. The results are compared to those obtained by the usual approach that employs a group velocity calculation. We consider both the case in which the frequency lies within passing band and the situation in which the frequency is in the range of a partial band gap. The agreements and discrepancies between various averaging schemes and the group velocity approach are discussed in detail. The results indicate that the group velocity can be obtained by an appropriate averaging method. Existing experimental methods are also discussed.

Journal Article↗
PubMed2004

Frozen water waves over rough topographical bottoms.

The propagation of surface water waves over rough topographical bottoms is investigated by the multiple scattering theory. It is shown that the waves can be localized spatially through the process of multiple scattering and wave interference, a peculiar wave phenomenon which has been previously discussed for frozen light in optical systems [Nature 390, 661 (1997)]]. This paper demonstrates that when frozen, the transmission of the waves falls off exponentially, and a cooperative behavior appears, fully supporting previous predictions. A graphic method is used to illustrate this distinct phase state in the wave propagation.

Journal Article↗
PubMed2004

Negative-refraction-like behavior revealed by arrays of dielectric cylinders.

We investigate the electromagnetic propagation in two-dimensional photonic crystals, formed by parallel dielectric cylinders embedded in a uniform medium. The transmission of electromagnetic waves through prism structures is calculated by the standard multiple scattering theory. The results demonstrate that, in certain frequency regimes and when the propagation inside the scattering media is not considered, the transmission behavior mimics the negative refraction expected for a left-handed material. This feature may illusively lead to the conclusion that a negative refraction is observed and it obeys Snell's law of negative refraction. Possible implications for current experimental and theoretical studies of negative refraction are also discussed.

Journal Article↗
PubMed2004

Guiding optical flows by photonic crystal slabs made of dielectric cylinders.

We investigate the electromagnetic propagation in two-dimensional photonic crystals, formed by parallel dielectric cylinders embedded in a uniform medium. The frequency band structure is computed using the standard plane-wave expansion method, while the propagation and scattering of the electromagnetic waves are calculated by the multiple scattering theory. It is shown that within partial band gaps, the waves tend to bend away from the forbidden directions. Such a property may render novel applications in manipulating optical flows. In addition, the relevance with the imaging by flat photonic crystal slabs will also be discussed.

Journal Article↗
PubMed2004

Propagation inhibition and localization of electromagnetic waves in two-dimensional random dielectric systems.

We rigorously calculate the propagation and scattering of electromagnetic waves by rectangular and random arrays of dielectric cylinders in a uniform medium. For regular arrays, the band structures are computed and complete bandgaps are discovered. For random arrays, the phenomenon of wave transmission and scattering is investigated and compared in two scenarios: (1) Wave propagating through the array of cylinders; this is the scenario which has been commonly considered in the literature, and (2) wave transmitted from a source located inside the ensemble. We show that within complete band gaps, results from the two scenarios are similar. Outside the gaps, however, there could be a distinct difference, that is, wave transmission can be inhibited by disorders in the first scenario, but such an inhibition may not prevail in the second scenario.

Journal Article↗
PubMed2004

Band gaps in the propagation and scattering of surface water waves over cylindrical steps.

Here we investigate the propagation and scattering of surface water waves in the presence of arrays of bottom-mounted cylindrical steps. Both periodic and random arrangements of the steps are considered. The wave transmission through the arrays is computed using the multiple scattering method based upon a recently derived formulation. For the periodic case, the results are compared to the band structure calculation. We demonstrate that complete band gaps can be obtained in such a system. Furthermore, we show that the randomization of the location of the steps can significantly reduce the transmission of water waves. Comparison with other systems is also discussed.

Journal Article↗
PubMed2004

Dilated cardiomyopathy caused by tissue-specific ablation of SC35 in the heart.

Many genetic diseases are caused by mutations in cis-acting splicing signals, but few are triggered by defective trans-acting splicing factors. Here we report that tissue-specific ablation of the splicing factor SC35 in the heart causes dilated cardiomyopathy (DCM). Although SC35 was deleted early in cardiogenesis by using the MLC-2v-Cre transgenic mouse, heart development appeared largely unaffected, with the DCM phenotype developing 3-5 weeks after birth and the mutant animals having a normal life span. This nonlethal phenotype allowed the identification of downregulated genes by microarray, one of which was the cardiac-specific ryanodine receptor 2. We showed that downregulation of this critical Ca2+ release channel preceded disease symptoms and that the mutant cardiomyocytes exhibited frequency-dependent excitation-contraction coupling defects. The implication of SC35 in heart disease agrees with a recently documented link of SC35 expression to heart failure and interference of splicing regulation during infection by myocarditis-causing viruses. These studies raise a new paradigm for the etiology of certain human heart diseases of genetic or environmental origin that may be triggered by dysfunction in RNA processing.

Animals↗
PubMed2003

Simulation study of localization of electromagnetic waves in two-dimensional random dipolar systems.

We study the propagation and scattering of electromagnetic waves by random arrays of dipolar cylinders in a uniform medium. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for electromagnetic fields. For certain ranges of frequencies, spatially localized electromagnetic waves appear in such a simple but realistic disordered system. Dependence of localization on the frequency, radiation damping, and filling factor is shown. The spatial behavior of the total, coherent, and diffusive waves is explored in detail, and found to comply with a physical intuitive picture. A phase diagram characterizing localization is presented, in agreement with previous investigations on other systems.

Journal Article↗
PubMed2003

Diffusive and localization behavior of electromagnetic waves in a two-dimensional random medium.

In this paper, we discuss the transport phenomena of electromagnetic waves in a two-dimensional random system which is composed of arrays of electrical dipoles, following the model presented earlier by Erdogan et al. [J. Opt. Soc. Am. B 10, 391 (1993)]. A set of self-consistent equations is presented, accounting for the multiple scattering in the system, and is then solved numerically. A strong localization regime is discovered in the frequency domain. The transport properties within, near the edge of, and nearly outside the localization regime are investigated for different parameters such as filling factor and system size. The results show that within the localization regime, waves are trapped near the transmitting source. Meanwhile, the diffusive waves follow an intuitive but expected picture. That is, they increase with traveling path as more and more random scattering incurs, followed by a saturation, then start to decay exponentially when the travelling path is large enough, signifying the localization effect. For the cases where the frequencies are near the boundary of or outside the localization regime, the results of diffusive waves are compared with the diffusion approximation, showing less encouraging agreement as in other systems [Asatryan et al., Phys. Rev. E 67, 036605 (2003)].

Journal Article↗
PubMed2003

Water wave propagation and scattering over topographical bottoms.

Here we provide a derivation of the formula recently used for investigating Bragg resonance in waves on a shallow fluid over a periodically drilled bottom [M. Torres et al., Phys. Rev. E 63, 011204 (2000)]. The equation is also compared with other existing theories. As an application, the theory is extended to the case of water waves propagating over a column with an arbitrary array of cylindrical steps. For a regular array, the formulation for computing band structures is also presented.

Journal Article↗
PubMed2003

Localization of classical waves in two-dimensional random media: a comparison between the analytic theory and exact numerical simulation.

The localization length of classical waves in two-dimensional random media is calculated exactly, and is compared with the theoretical prediction from the current analytic theory. Significant discrepancies are observed. It is also shown that as the frequency varies, critical changes in the localization behavior can occur. However, by a rescaling of parameters the two results tend to match each other for weak scattering. Possible reasons for the discrepancies are discussed.

Journal Article↗
PubMed2003

Theoretical analysis of the focusing of acoustic waves by two-dimensional sonic crystals.

Motivated by a recent experiment on acoustic lenses, we perform numerical calculations based on a multiple scattering technique to investigate the focusing of acoustic waves with sonic crystals formed by rigid cylinders in air. The focusing effects for crystals of various shapes are examined. The dependence of the focusing length on the filling factor is also studied. It is observed that both the shape and filling factor play a crucial role in controlling the focusing. Furthermore, the robustness of the focusing against disorders is studied. The results show that the sensitivity of the focusing behavior depends on the strength of positional disorders. The theoretical results compare favorably with the experimental observations, reported by Cervera, et al. [Phys. Rev. Lett. 88, 023902 (2002)].

Journal Article↗
PubMed2002

Localization of electromagnetic waves in a two-dimensional random medium.

Motivated by previous investigations on the radiative effects of the electric dipoles embedded in structured cavities, localization of electromagnetic waves in two dimensions is studied ab initio for a system consisting of many randomly distributed two-dimensional dipoles. A set of self-consistent equations, incorporating all orders of multiple scattering of the electromagnetic waves, is derived from first principles and then solved numerically for the total electromagnetic field. The results show that spatially localized electromagnetic waves are possible in such a simple but realistic disordered system. When localization occurs, a coherent behavior appears and is revealed as a unique property differentiating localization from either the residual absorption or the attenuation effects.

Journal Article↗