A Novel Approach to Implementing On-Chip Synchronous Detection for CMOS Optical Detector Systems

A phase-switching approach suppresses the need to employ a precise multiplier for synchronous demodulation. An improved solution for implementing on-chip synchronous detection consists of using a switched-phase amplifier, which combines pre-amplification and phase-switching operations. This enables circuit simplification, voltage lowering, and power and surface savings. A detector-associated circuit realising pre-amplification and synchronous demodulation is proposed. It includes a transimpedance amplifier, a switched-phase amplifier and a low-pass filter. All these building blocks are designed to operate under a minimum supply of 2 V, using a double-poly, 0.8-m CMOS process. The designed circuit is to be integrated with a CMOS optical detector for portable applications. System-level simulations (including the detector model) are performed to validate the system operation, and to estimate performances. The sensitivity of the system in terms of minimum detectable optical signal (which is synchronously modulated) is evaluated to be 2.2 10^–14 W/mm² in normal measuring conditions.     

Depth profile analyses of nc-TiC/a-C:H coating prepared by balanced magnetron sputtering

Nanocrystalline titanium carbide embedded in an hydrogenated amorphous carbon matrix (nc-TiC/a-C:H) shows high hardness and Young's modulus together with low wear and low friction coefficient. In this paper, we report on the preparation of well adherent nc-TiC/a-C:H coatings ~ 5 μm thick on stainless steel substrates using a well balanced magnetic field configuration and only very low power RF bias on the substrate. Hardness and Young's modulus of these coatings are 43 GPa and 380 GPa, respectively. The mechanical properties – hardness and Young's modulus – measured from the coating's top reach the values obtained at optimized experiments where the unbalanced magnetic field configuration was used. A simple method of depth profiling suitable for evaluation of mechanical properties of several micrometers thick coatings is developed and employed. The paper reports on the depth profile analyses of the coating hardness, Young's modulus, composition and morphology.     

Structure,nonstoichiometry, sintering and oxygen permeability of perovskite SrCo1−2x(Fe,Nb)xO3−δ (x = 0.05, 0.10) oxides

The novel Fe/Nb co-substituted SrCo_1?2x(Fe,Nb)_xO_3?δ (x = 0.05, 0.10) oxides have been synthesized and characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG), and scanning electron microscopy (SEM). The XRD and DSC results demonstrate that the structural stability of the Fe/Nb co-substituted samples x = 0.05, 0.10 is improved greatly compared to the sample x = 0.00. The Fe/Nb co-doping in the SrCoO_3?δ oxide results in the improved structural stability of the SrCo_1?2x(Fe,Nb)_xO_3?δ (x = 0.05, 0.10) oxides. The nonstoichiometric and sintering properties were investigated by TG and SEM, and the oxygen permeation fluxes were measured at 800–950 °C for the sample x = 0.10. The improved oxygen permeability of the ceramic SrCo_1?2x(Fe,Nb)_xO_3?δ (x = 0.10) membrane compared to the (Ba_0.5Sr_0.5)(Co_0.8Fe_0.2)O_3?δ and SrCo_0.8Fe_0.2O_3–δ membranes, was observed under an air/He oxygen partial pressure gradient at 800–950 °C.     

Reliability and availability analysis for an on board computer in a satellite system using standby redundancy and rejuvenation

A large number of technologies are used in a satellite because it is hard difficult to repair and replace its components after it has been launched. Furthermore, there are many threats to the satellite such as software aging, environmental problems and network attacks. Because of this nature, it is important that the satellite operates well in spite of the occurrence of hardware and/or software faults. In particular, software aging in the on-board computer (OBC) causes unavailability of a whole satellite system. In this paper, we propose to adopt software rejuvenation for OBC in conjunction with cold, hot and warm standby redundancy in a satellite system. We use stochastic reward nets (SRN) to model OBC with cold, hot and warm standby redundancy and model OBC with that redundancy with software rejuvenation. We compare the models in terms of steady state availability and downtime cost. Sensitivity analysis with respect to some parameters is used to find bottlenecks of the models. Finally, we present a reliability model and analysis with cost consideration.     

Inkjet-printed resistors with a wide resistance range for printed read-only memory applications

Inkjet-printed resistors with resistance values varying over five orders of magnitude were demonstrated on a flexible substrate. The resistivity of printed lines of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was altered by using different ink formulations and by employing an over-print technique, while the length of the printed resistor line remained unchanged. This technique was then applied to fabricate a printed read-only memory device that consisted of an array of resistors. The concept of printing reliable, visually identical resistors with controlled resistance values provides an important building block for low cost, printed electronic circuit applications.     

Nonstationary fault detection and diagnosis for multimode processes

Fault isolation based on data‐driven approaches usually assume the abnormal event data will be formed into a new operating region, measuring the differences between normal and faulty states to identify the faulty variables. In practice, operators intervene in processes when they are aware of abnormalities occurring. The process behavior is nonstationary, whereas the operators are trying to bring it back to normal states. Therefore, the faulty variables have to be located in the first place when the process leaves its normal operating regions. For an industrial process, multiple normal operations are common. On the basis of the assumption that the operating data follow a Gaussian distribution within an operating region, the Gaussian mixture model is employed to extract a series of operating modes from the historical process data. The local statistic T² and its normalized contribution chart have been derived for detecting abnormalities early and isolating faulty variables in this article. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Tracing Metabolic Fate of Mitochondrial Glycine Cleavage System Derived Formate In Vitro and In Vivo

Folate-mediated one-carbon (1C) metabolism is a major target of many therapies in human diseases. Studies have focused on the metabolism of serine 3-carbon as it serves as a major source for 1C units. The serine 3-carbon enters the mitochondria transferred by folate cofactors and eventually converted to formate and serves as a major building block for cytosolic 1C metabolism. Abnormal glycine metabolism has been reported in many human pathological conditions. The mitochondrial glycine cleavage system (GCS) catalyzes glycine degradation to CO₂ and ammonium, while tetrahydrofolate (THF) is converted into 5,10-methylene-THF. GCS accounts for a substantial proportion of whole-body glycine flux in humans, yet the particular metabolic route of glycine 2-carbon recycled from GCS during mitochondria glycine decarboxylation in hepatic or bone marrow 1C metabolism is not fully investigated, due to the limited accessibility of human tissues. Labeled glycine at 2-carbon was given to humans and primary cells in previous studies for investigating its incorporations into purines, its interconversion with serine, or the CO₂ production in the mitochondria. Less is known on the metabolic fate of the glycine 2-carbon recycled from the GCS; hence, a model system tracing its metabolic fate would help in this regard. We took the direct approach of isotopic labeling to further explore the in vitro and in vivo metabolic fate of the 2-carbon from [2-¹³C]glycine and [2-¹³C]serine. As the 2-carbon of glycine and serine is decarboxylated and catabolized via the GCS, the original 13C-labeled 2-carbon is transferred to THF and yield methyleneTHF in the mitochondria. In human hepatoma cell-lines, 2-carbon from glycine was found to be incorporated into deoxythymidine (dTMP, dT + 1), M + 3 species of purines (deoxyadenine, dA and deoxyguanine, dG), and methionine (Met + 1). In healthy mice, incorporation of GCS-derived formate from glycine 2-carbon was found in serine (Ser + 2 via cytosolic serine hydroxy methyl transferase), methionine, dTMP, and methylcytosine (mC + 1) in bone marrow DNA. In these experiments, labeled glycine 2-carbon directly incorporates into Ser + 1, A + 2, and G + 2 (at C2 and C8 of purine) in the cytosol. It is noteworthy that since the serine 3-carbon is unlabeled in these experiments, the isotopic enrichments in dT + 1, Ser + 2, dA + 3, dG + 3, and Met + 1 solely come from the 2-carbon of glycine/serine recycled from GCS, re-enters the cytosolic 1C metabolism as formate, and then being used for cytosolic syntheses of serine, dTMP, purine (M + 3) and methionine. Taken together, we established model systems and successfully traced the metabolic fate of mitochondrial GCS-derived formate from glycine 2-carbon in vitro and in vivo. Nutritional supply significantly alters formate generation from GCS. More GCS-derived formate was used in hepatic serine and methionine syntheses, whereas more GCS-derived formate was used in dTMP synthesis in the bone marrow, indicating that the utilization and partitioning of GCS-derived 1C unit are tissue-specific. These approaches enable better understanding concerning the utilization of 1C moiety generated from mitochondrial GCS that can help to further elucidate the role of GCS in human disease development and progression in future applications. More studies on GCS using these approaches are underway.     

Production of chemicals by cracking pyrolytic tar from Loy Yang coal over iron oxide catalysts in a steam atmosphere

Iron oxide catalysts containing metal promoters were tested to evaluate whether they could be applied to the coal tar obtained from the pyrolysis of Loy Yang coal. Catalytic cracking of the coal tar in a steam atmosphere was conducted in a fixed-bed reactor at 773 K and ambient atmospheric pressure. For iron oxide catalysts containing cerium, zirconium, and aluminium, the total yield of monocyclic aromatic hydrocarbons, phenols, and ketones exceeded 40 mol-C% on a tar basis, while about 97 wt.% of the initial heavy tar was decomposed. The combination of cerium, zirconium, and aluminium improved the activity of the iron oxide catalyst. Moreover, the addition of steam to the tar vapour increased the yield of ketones and made the catalyst more durable.     

Local immune response in infertile patients with minimal endometriosis

BACKGROUND: Prostatic intraepithelial neoplasia (PIN) is the most likely precursor of prostatic adenocarcinoma. However, the ultrastructural features of PIN have not been defined in properly fixed tissues. METHODS: In this study, we examined a total of 84 acini from 11 cases of high-grade PIN and matched benign epithelium and adenocarcinoma from patients undergoing radical prostatectomy. Specimens from each case were immediately fixed in glutaraldehyde after surgical removal and processed routinely to ensure optimal preservation. RESULTS: High-grade PIN displayed ultrastructural features that were intermediate between those of benign epithelium and adenocarcinoma. These included the presence of cells with a variable number of cytoplasmic secretory vacuoles, luminal apocrine blebs, large nuclei with coarsely clumped chromatin, enlarged nucleoli, prominent apical microvilli, intact or discontinuous basal cell layer, and intact basement membrane. CONCLUSIONS: Our results indicate that PIN shares many ultrastructural characteristics with adenocarcinoma, supporting its role as a premalignant lesion.