Asymmetrical response of semiconductor lasers in optical systems

The symmetry of the optical outputs of a semiconductor laser diode having front and rear facets with equal reflectivity is destroyed by the injection of a reflected signal, even of weak intensity, from one side: this asymmetry must be taken into account when designing laser packages and integrated circuits. A systematic experimental investigation is presented. Moreover, the behaviour of the system, i.e., the appearance of certain asymmetrical features together with the survival of the symmetry of other features, can be accounted for on the basis of a microscopic model, providing a link between the optical outputs from the two facets.Italtel-Advanced Technology Laboratory Cascino Castelletto, CLTB-20019 Settimo Milanese, Italy. Consorzio Milano Ricerche Via Cicognara, 7-20129 Milano, Italy. Physics Department, University of Milan, Via Celoria, 16-20133 Milano, Italy. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 99, No. 3, pp. 364–369, June, 1994.     

A Remark on the Sobolev Regularity of Classical Solutions of Strongly Elliptic Equations

We prove that C^2,α(Ω ) solutions of problem (1.2) below are in H^m+2(Ω) for all m ∈ ?, if f and the coefficients are in H^m (Ω) n C^0,α (Ω ) Previously, this result was explicitly known only if m> n/2 (or if m = 0). A similar result holds for the quasi-linear equation (1.11) below.     

Stability and bifurcations of symmetric periodic orbits

Se un problema Hamiltoniano integrabile non degenere, come si può ottenere dal problema dei due corpi in coordinate rotanti, è perturbato con una funzione potenziale simmetrica rispetto ad un asse, le proprietà di simmetria delle soluzioni consentono di semplificare la ricerca, di orbite periodiche. In tal modo si ottiene un teorema di continuazione delle orbite periodiche che fornisce più informazioni di quello classico. La funzione che descrive la simmetria delle orbite è genericamente una funzione di Morse, e le biforcazioni di orbite periodiche simmetriche possono essere descritte in termini di punti singolari e di valori critici di tale funzione. II problema ristretto dei tre corpi ed il problema del satellite in un potenziale non axisimmetrico sono trattati come esempi. Le stesse biforcazioni possono anche essere descritte come singolarità degeneri della funzione generatrice della trasformazione canonica associata all'applicazione di Poincaré, cioè al trascorrere di un periodo sinodico. In tal modo le proprietà di stabilità lineare delle orbite periodiche, la segnatura dei punti singolari della funzione generatrice e l'andamento qualitativo della funzione di simmetria appaiono correlate tra loro. Ne risulta la possibilità di predire, prima di qualsiasi esperimento numerico, non solo la struttura generica delle biforcazioni delle orbite periodiche simmetriche, ma anche la stabilità di tutte le orbite periodiche coinvolte.     

Methane Direct Conversion on Mo/ZSM-5 Catalysts Modified by Pd and Ru

The effect of addition of Ru and Pd to Mo/HZSM-5 catalysts used in the dehydroaromatiza-tion of methane was investigated. Catalytic tests and temperature-programmed oxidation results showed that Pd-based catalysts were more selective to naphthalene and suffered strong deactivation. The presence of Ru improved the activity and stability, with a decrease in the carbonaceous deposit probably because of a mechanism of protection of the Mo2C surface.     

Integrated processes for use of pulps and lignins obtained from sugarcane bagasse and straw

Sugarcane bagasse and straw can be converted into pulps, oils, controlled-release formulations, chelating agents, and composites. This article reviews bagasse and straw conversion efforts in Brazil. Laboratory-scale processes were developed aiming at the integral use of these biomass byproducts. Organosolv pulping and oxidation of lignin are the most promising processes for the rational use of sugarcane residues. Fungal pretreatment and spectroscopic characterization are also discussed.     

Characterization of lidocaine:hydroxypropyl-β-cyclodextrin inclusion complex

An inclusion complex was prepared between the local anesthetic lidocaine (LDC) and hydroxypropyl-β-CD (HP-β-CD). The complex was characterized by thermal analysis (differential scanning calorimetry, DSC), UV absorption and high-pressure liquid chromatography (HPLC). DSC results were indicative of complexation, due to the loss of the characteristic endothermic peak of LDC (77 °C). Phase-solubility diagrams allowed the determination of the association constant between LDC and HP-β-CD (35.7 ± 4.7 M⁻¹). The rate of LDC release decreased after complexation and thermodynamic parameters from the HPLC studies (ΔG° = −2.65 kJ/mol) revealed that a stable complex was formed.     

Synthesis and Structural Studies of 4-Thioxopyrimidines with Antimicrobial Activities

Summary. This work describes a two-step, one-pot synthetic method for the formal aza-[3 + 3] cycloaddition between N-alkyl substituted enaminones and benzoyl isothiocyanate, which afforded 4-thioxopyrimidines in reasonable yields. Reaction of acyclic enaminone with a sterically hindered group attached to the nitrogen atom afforded pyridine-2-thione, yet in low yield. The antibacterial, antifungal, and trypanocidal activities of the thioxopyrimidines were evaluated and five compounds exhibited moderate activity against Candida albicans, Micrococcus luteus, and Trypanosoma cruzi. The solid state structures of a thioxopyrimidine, an organic disulfide, and a 1,2,4-triazole were determined by X-ray diffraction analysis.     

Proteomics Approach of Rapamycin Anti-Tumoral Effect on Primary and Metastatic Canine Mammary Tumor Cells In Vitro

Rapamycin is an antifungal drug with antitumor activity and acts inhibiting the mTOR complex. Due to drug antitumor potential, the aim of this study was to evaluate its effect on a preclinical model of primary mammary gland tumors and their metastases from female dogs. Four cell lines from our cell bank, two from primary canine mammary tumors (UNESP-CM1, UNESP-CM60) and two metastases (UNESP-MM1, and UNESP-MM4) were cultured in vitro and investigated for rapamycin IC₅₀. Then, cell lines were treated with rapamycin IC₅₀ dose and mRNA and protein were extracted in treated and non-treated cells to perform AKT, mTOR, PTEN and 4EBP1 gene expression and global proteomics by mass spectrometry. MTT assay demonstrated rapamycin IC₅₀ dose for all different tumor cells between 2 and 10 μM. RT-qPCR from cultured cells, control versus treated group and primary tumor cells versus metastatic tumor cells, did not shown statistical differences. In proteomics were found 273 proteins in all groups, and after data normalization 49 and 92 proteins were used for statistical analysis for comparisons between control versus rapamycin treatment groups, and metastasis versus primary tumor versus metastasis rapamycin versus primary tumor rapamycin, respectively. Considering the two statistical analysis, four proteins, phosphoglycerate mutase, malate dehydrogenase, l-lactate dehydrogenase and nucleolin were found in decreased abundance in the rapamycin group and they are related with cellular metabolic processes and enhanced tumor malignant behavior. Two proteins, dihydrolipoamide dehydrogenase and superoxide dismutase, also related with metabolic processes, were found in higher abundance in rapamycin group and are associated with apoptosis. The results suggested that rapamycin was able to inhibit cell growth of mammary gland tumor and metastatic tumors cells in vitro, however, concentrations needed to reach the IC₅₀ were higher when compared to other studies.