Design techniques for high-performance digital PLLs and CDRs

Phase-Locked Loops (PLLs) are essential building blocks in many communication systems. Designing high performance analog PLLs in the presence of technology imposed constraints such as leakage, poor analog transistor behavior, process variability, and low supply voltage is a challenging task. To overcome these drawbacks, digital PLLs (DPLLs) have recently emerged as an alternative to analog PLLs. In this work, a digital PLL employing a linear proportional path and a double integral path is proposed to achieve low jitter, wide operating range and low power. Moreover, the approach of bandwidth and tuning range tracking is achieved. The prototype DPLL fabricated in a 90nm CMOS process operates from 0.7 to 3.5GHz. At 2.5GHz, the proposed DPLL consumes only 1.6mW power and achieves 1.6ps r.m.s jitter. Moreover, the design techniques for a novel digital clock and data recovery (CDR) with linear loop dynamics are presented. The PLL-based digital CDR avoid the use of TDC, achieves static phase offset free (SPO-free) and well-controlled jitter transfer bandwidth. The prototype digital CDR fabricated in a 0:13μm CMOS process achieves error-free operation (BER < 10⁻¹²) for PRBS data sequences ranging from 2⁷-1 to 2³¹-1 and a near-constant bandwidth of 4.5MHz

Low Expression of DYRK2 (Dual Specificity Tyrosine Phosphorylation Regulated Kinase 2) Correlates with Poor Prognosis in Colorectal Cancer.

Dual-specificity tyrosine-phosphorylation-regulated kinase 2 (DYRK2) is a member of dual-specificity kinase family, which could phosphorylate both Ser/Thr and Tyr substrates. The role of DYRK2 in human cancer remains controversial. For example, overexpression of DYRK2 predicts a better survival in human non-small cell lung cancer. In contrast, amplification of DYRK2 gene occurs in esophageal/lung adenocarcinoma, implying the role of DYRK2 as a potential oncogene. However, its clinical role in colorectal cancer (CRC) has not been explored. In this study, we analyzed the expression of DYRK2 from Oncomine database and found that DYRK2 level is lower in primary or metastatic CRC compared to adjacent normal colon tissue or non-metastatic CRC, respectively, in 6 colorectal carcinoma data sets. The correlation between DYRK2 expression and clinical outcome in 181 CRC patients was also investigated by real-time PCR and IHC. DYRK2 expression was significantly down-regulated in colorectal cancer tissues compared with adjacent non-tumorous tissues. Functional studies confirmed that DYRK2 inhibited cell invasion and migration in both HCT116 and SW480 cells and functioned as a tumor suppressor in CRC cells. Furthermore, the lower DYRK2 levels were correlated with tumor sites (P = 0.023), advanced clinical stages (P = 0.006) and shorter survival in the advanced clinical stages. Univariate and multivariate analyses indicated that DYRK2 expression was an independent prognostic factor (P &lt; 0.001). Taking all, we concluded that DYRK2 a novel prognostic biomarker of human colorectal cancer

The ROS/NF-κB/NR4A2 Pathway is Involved in H\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e2\u3c/sub\u3e Induced Apoptosis of Resident Cardiac Stem Cells via Autophagy

Cardiac stem cells (CSCs)-based therapy provides a promising avenue for the management of ischemic heart diseases. However, engrafted CSCs are subjected to acute cell apoptosis in the ischemic microenvironment. Here, stem cell antigen 1 positive (Sca-1+) CSCs proved to own therapy potential were cultured and treated with H2O2 to mimic the ischemia situation. As autophagy inhibitor, 3-methyladenine (3MA), inhibited H2O2-induced CSCs apoptosis, thus we demonstrated that H2O2 induced autophagy-dependent apoptosis in CSCs, and continued to find key proteins responsible for the crosstalk between autophagy and apoptosis. Nuclear Receptor Subfamily 4 Group A Member 2 (NR4A2), increased upon cardiomyocyte injury with unknown functions in CSCs, was increased by H2O2. NR4A2 siRNA attenuated H2O2 induced autophagy and apoptosis in CSCs, which suggested an important role of NR4A2 in CSCs survival in ischemia conditions. Reactive oxygen species (ROS) and NF- κB (P65) subunit were both increased by H2O2. Either the ROS scavenger, N-acetyl-lcysteine (NAC) or NF-κB signaling inhibitor, bay11-7082 could attenuate H2O2-induced autophagy and apoptosis in CSCs, which suggested they were involved in this process. Furthermore, NAC inhibited NF-κB activities, while bay11-7082 inhibited NR4A2 expression, which revealed a ROS/NF-κB/NR4A2 pathway responsible for H2O2- induced autophagy and apoptosis in CSCs. Our study supports a new clue enhancing the survival rate of CSCs in the infarcted myocardium for cell therapy in ischemic cardiomyopathy

Modeling And Experimental Study On A Direct Expansion Based Enhanced Dehumidification Air Conditioning System

Direct expansion (DX) air conditioning (A/C) systems are widely used for controlling indoor air temperature and humidity in various buildings in hot and humid climates since they are simpler and more energy efficient, and generally cost less to own and maintain. However, it is often problematic for a DX A/C system to provide desired humidity control due to the current system design trends, variable weather conditions and the commonly used control strategies for DX A/C systems. Therefore, a standalone DX based enhanced dehumidification air conditioning (EDAC) system is proposed to provide suitable indoor humidity control at different seasons. There are two evaporators in the EDAC system, thus it could act as a dehumidifier (ADO mode) on the days when less or no additional cooling is required by employing one evaporator as a reheating coil, or act as an enhanced dehumidification A/C system (EDAC mode) by functioning two evaporators to separately deal with sensible and latent cooling. A prototype experimental EDAC system was established in a laboratory. The operational characteristics of the EDAC system at ADO mode in terms of the moisture removal capacity (MRC), the specific moisture extraction rate (SMER) and the resulted supply air temperature were investigated and reported in this paper. Firstly, the experimental results on operational characteristics are reported. Secondly, the development of a steady-state mathematical model for the ADO mode of the EDAC system is presented. The developed model was thereafter used to study the influence of different sizes of the evaporator and the reheating coil on the operational characteristic of the EDAC system at ADO mode. The study results could lead to a better understanding of the operational characteristics of the EDAC system, facilitating its design, operation and control

In Situ TEM Study of the Degradation of PbSe Nanocrystals in Air

PbSe nanocrystals have attracted widespread attention due to a variety of potential applications. However, the practical utility of these nanocrystals has been hindered by their poor air stability, which induces undesired changes in the optical and electronic properties. An understanding of the degradation of PbSe nanocrystals when they are exposed to air is critical for improving the stability and enhancing their applications. Here, we use in situ transmission electron microscopy (TEM) with an environmental cell connected to air to study PbSe nanocrystal degradation triggered by air exposure. We have also conducted a series of complementary studies, including in situ environmental TEM study of PbSe nanocrystals exposed to pure oxygen and PbSe nanocrystals in H2O using a liquid cell, and ex situ experiments, such as O2 plasma treatment and thermal heating of PbSe nanocrystals under different air exposure. Our in situ observations reveal that when PbSe nanocrystals are exposed to air (or oxygen) under electron beam irradiation, they experience a series of changes, including shape evolution of individual nanocrystals with the cuboid intermediates, coalescence between nanocrystals, and formation of PbSe thin films through drastic solid-state fusion. Further studies show that the PbSe thin films transform into an amorphous Pb rich phase or eventually pure Pb, which suggest that Se reacts with oxygen and can be evaporated under electron beam illumination. These various in situ and ex situ experimental results indicate that PbSe nanocrystal degradation in air is initiated by the dissociation and removal of ligands from the PbSe nanocrystal surface

Ekonomski rast i emisija ugljika u Kini: Kuznetsova krivulja prostorne ekonometrije

Economic development has largely contributed to the increment of CO2 emission. This study uses spatial econometric models to investigate the relationship between economic growth and carbon emission in China with data of 30 provinces of China during the period of 2000 to 2012. Results show that the relationship between carbon emission and economic growth in China during the recent decade has the development tendency toward an inverse U-shaped curve, approximately confirming the carbon emission’s Kuznets curve hypothesis in China. There exists a significant spatial correlation between carbon emission and economic growth,implying that carbon emission in a province may be influenced by economic growth in adjacent provinces. When economic growth reaches 279.91 million Yuan/km2 GDP (at a comparable price in 2000), the contradiction between economic growth and carbon emission begins to be gradually alleviated. These findings provide new insights and valuable information for reducing carbon emissions in China.Gospodarski razvoj uvelike je pridonio povećanju emisije CO2. Ova studija koristi prostorne ekonometrijske modele za istraživanje odnosa između gospodarskog rasta i emisije ugljika u Kini s podacima iz 30 pokrajina Kine u razdoblju od 2000. do 2012. godine. Rezultati pokazuju da tijekom posljednjeg desetljeća odnos emisije ugljika i gospodarskog rasta u Kini ima tendenciju razvoja prema inverznoj krivulji U-oblika, približno potvrđujući hipotezu Kuznetsove krivulje emisije ugljika u Kini. Postoji značajna prostorna povezanost između emisije ugljika i ekonomskog rasta, što implicira da na emisiju ugljika u pokrajini može utjecati gospodarski rast u susjednim pokrajinama. Nakon što je ekonomski rast dosegnuo omjer od 279,91 milijuna Yuan/km2 BDP-a (usporediva cijena u 2000. godini), kontradikcija između gospodarskog rasta i emisije ugljika počinje se postupno ublažavati. Ovi rezultati pružaju nove uvide i vrijedne informacije kako reducirati emisije ugljika u Kini