On the existence of solutions of the Riccati differential equation

We generalize a technique given in C. Martin [1], to obtain a characterization of finite escape times for time-varying Riccati equations which also apply to the non-definite case.     

Targeting Tumor Acidosis and Regulatory T Cells Unmasks Anti-Metastatic Potential of Local Tumor Ablation in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an immunologically heterogenous disease that lacks clinically actionable targets and is more likely to progress to metastatic disease than other types of breast cancer. Tumor ablation has been used to increase response rates to checkpoint inhibitors, which remain low for TNBC patients. We hypothesized that tumor ablation could produce an anti-tumor response without using checkpoint inhibitors if immunosuppression (i.e., Tregs, tumor acidosis) was subdued. Tumors were primed with sodium bicarbonate (200 mM p.o.) to reduce tumor acidosis and low-dose cyclophosphamide (100–200 mg/kg i.p.) to deplete regulatory T cells, as has been shown independently in previous studies. A novel injectable ablative was then used to necrose the tumor, release tumor antigens, and initiate an immune event that could create an abscopal effect. This combination of bicarbonate, cyclophosphamide, and ablation, called “BiCyclA”, was tested in three syngeneic models of TNBC: E0771 (C57BL/6), 67NR (BALB/c), and 4T1-Luc (BALB/c). In E0771 and 67NR, BiCyclA therapy significantly reduced tumor growth and cured 5/7 and 6/10 mice 50 days after treatment respectively. In the metastatic 4T1-Luc tumors, for which surgery and checkpoint inhibitors fail, BiCyclA cured 5/10 mice of primary tumors and lung metastases. Notably, CD4+ and CD8+ T cells were found to be crucial for the anti-metastatic response, and cured mice were able to resist tumor rechallenge, suggesting production of immune memory. Reduction of tumor acidity and regulatory T cells with ablation is a simple yet effective therapy for local and systemic tumor control with broad applicability as it is not limited by expensive supplies.     

Controllability on classical Lie groups

We consider the problem of accessibility and controllability of certain bilinear systems. These evolve on Lie groups whose Lie algebras are the normal real forms of complex simple Lie algebras. Previous results by other authors were obtained under the assumption that the controlled vector field is strongly regular. Our paper is aimed at weakening this requirement, and involves relating the root structure of elements in a Lie algebra as above to the nodal connection graphs obtained from their standard matrix representations. This is in turn related to a standard irreducibility assumption on the uncontrolled vector field. The abstract results on generation of Lie algebras are of some independent interest. The work of this author was supported in part by a Fulbright grant, while she was visiting the Arizona State University, and by the Centro de Matemática da Universidade de Coimbra/INIC. The work of this author was partially supported by AFOSR Contract No. 85-0224A.     

Performance of sol–gel Titanium Mixed Metal Oxide electrodes for electro-catalytic oxidation of phenol

Mixed metal oxides SnO₂–RuO₂–IrO₂, Ta₂O₅–IrO₂ and RhO₂–IrO₂ were immobilised on a Ti substrate using sol–gel techniques. The Ti mixed metal oxides were characterized in terms of morphology using scanning electron microscopy. Cyclic voltammetric responses of phenol at Ti/SnO₂–RuO₂–IrO₂, Ti/Ta₂O₅–IrO₂ and Ti/RhO₂–IrO₂ electrodes were evaluated and showed significantly low potentials for Ti/Ta₂O₅–IrO₂ (+100 mV), Ti/SnO₂–RuO₂–IrO₂ (+200 mV) and Ti/RhO₂–IrO₂ (−100 mV). The degradation of phenol in aqueous solution and its intermediates were investigated by bulk electrolysis and quantitatively assessed by HPLC analysis to elucidate the decomposition pathways and to develop a kinetic model for the electro-catalytic oxidation of phenol over Ti mixed metal oxides. Ring compounds, benzoquinone/hydroquinone, catechol, and short chain organics, carboxylic acids, have been identified as intermediate products for the electro-catalytic oxidation of phenol. Fundamental kinetic data were obtained for the conversion of phenol at these electrodes and was found to proceed in accordance with the pseudo-first-order kinetics with respect to the phenol concentration.     

Effect of antibiotic treatment on inflammatory markers and lung function in cystic fibrosis patients with Pseudomonas cepacia

BACKGROUND: The acquisition of Pseudomonas cepacia in patients with cystic fibrosis is associated with increasing deterioration in lung function and more frequent hospital admissions. Pseudomonas cepacia is usually resistant to several antibiotics in vitro, but the response of patients colonised with the organism has not been extensively studied in vivo. METHODS: A three month prospective study was performed to investigate the response of 14 Ps cepacia positive patients and 10 Ps cepacia negative patients to a two week course of intravenous antibiotics. All those who were Ps cepacia negative and six of the 14 Ps cepacia positive patients had Ps aeruginosa in their sputum which was sensitive to the prescribed therapy. The inflammatory markers C-reactive protein, white blood cell count, serum lactoferrin, neutrophil elastase/alpha 1-antitrypsin complex, and tumour necrosis factor alpha were measured at the start and end of each antibiotic course. RESULTS: The median (range) % improvement in baseline FEV1 and FVC following treatment in the group as a whole was 15.2% (-23.5% to 156.3%) and 23.9% (-36.8% to 232.7%) respectively. There was no statistical difference in improvement in lung function, body weight, or inflammatory markers between individuals who were Ps cepacia positive and those who were Ps cepacia negative. CONCLUSIONS: Patients who are Ps cepacia positive appear to respond as well to intravenous antibiotics as those who are Ps cepacia negative, despite having lower lung function and a bacterium in their sputum which is resistant in vitro to the antibiotics used.     

AC scan path selection for physical debugging

Commercial EDA tools support critical-path identification, as well as transition and path delay ATPG. But how can you narrow down the target faults or paths, and which ATPG technique should you use? The authors present a practical methodology addressing these important questions.     

以硬件为中心的方案打造具有更高可靠性的医疗设备

几乎每个使用手机的人都会有过一两次掉线的经历.虽然这些产品以及其他消费类产品的系统故障或者小毛病会带来不方便,但它们不会造成灾难性的后果.然而,医疗电子产品的一次系统故障或者毛病,却会危及生命,是致命的.这就是为什么医疗设备,医疗系统中集成的器件以及这些器件上运行的软件必须通过严格的测试,并符合食品药品监督管理局(FDA)的严格要求.     

A robust capillary electrophoresis method for the determination of organic acids in wines

A robust capillary electrophoresis (CE) method for the determination of the six main organic acids in wines is described. The CE method is based on the use of 2,6- pyridinedicarboxylic acid (PDC) as background electrolyte (BGE) for the indirect UV detection of tartaric, malic, citric, succinic, acetic and lactic acids. Ethylenediaminetetracarboxylic acid (EDTA) was added to the BGE to eliminate interferences from trace metals on the determination of citric acid. Problems related to linearity reported in the literature using the same BGE were shown to be the result of the sample pH being lower than that of the buffer. Although this could be overcome simply by adjusting the pH of the sample, electrokinetic injection was found to be a better alternative, improving at the same time the sensitivity of the determination. Linearity over the range 100–5,000 mg/l (ppm) for all acids was achieved, requiring only 80× dilution of standards and samples prior to injection. Within day repeatabilitys (n=7) of migration times (RSD%<0.15) and peak areas (RSD%<5) as determined for a wine sample were found to be excellent. The method was applied to 20 South African wine samples, and the results are compared to data obtained by ion-exclusion liquid chromatography. Succinic acid was consistently overestimated using the latter technique, while for the other acids good agreement between the methods was noted.