Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
1.
Hautarzt ; 72(6): 469-473, 2021 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-33871671

RESUMO

In accordance with § 202 SGB VII, physicians in Germany have a legal obligation to report to the statutory accident insurance institution any justified suspicion of an occupational disease. With regard to skin diseases, various occupational disease numbers (Berufskrankheitennummer = BK No.) can be considered, depending on the type of disease and the type of exposure, e.g. BK No. 3101, 3102, 3104, BK No. 5102 and others in addition to the most common BK No. 5101 and BK No. 5103. The prerequisite for a well-founded suspicion is that occupational effects exist or existed which can be brought into a causal relationship with the skin disease. Form F6000 "Medical notification of a suspected occupational disease" is used for reporting. In the case of the numerically most significant BK No. 5101, there is the special feature that even if the skin disease is classified as occupationally caused, but not as severe or repeatedly relapsing, according to § 41 (1) of the contract between physicians and the accident insurance institutions, every physician is obliged to immediately present the insured person to a dermatologist so that the so-called dermatologist procedure can be initiated to enable the rapid initiation of prevention. Since 1 January 2021, it has been stipulated that the dermatologist's report must be submitted in every case-i.e. both when there is merely the possibility and when there is a well-founded suspicion of the existence of a BK No. 5101. This ensures that preventive measures can be quickly and effectively implemented.


Assuntos
Doenças Profissionais , Dermatopatias , Dermatologistas , Alemanha , Humanos , Doenças Profissionais/diagnóstico , Dermatopatias/diagnóstico
2.
Nucleic Acids Res ; 35(15): 5085-95, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17652327

RESUMO

The prediction of operons in Mycobacterium tuberculosis (MTB) is a first step toward understanding the regulatory network of this pathogen. Here we apply a statistical model using logistic regression to predict operons in MTB. As predictors, our model incorporates intergenic distance and the correlation of gene expression calculated for adjacent gene pairs from over 474 microarray experiments with MTB RNA. We validate our findings with known examples from the literature and experimentation. From this model, we rank each potential operon pair by the strength of evidence for cotranscription, choose a classification threshold with a true positive rate of over 90% at a false positive rate of 9.1%, and use it to construct an operon map for the MTB genome.


Assuntos
Mapeamento Cromossômico/métodos , Mycobacterium tuberculosis/genética , Óperon , Perfilação da Expressão Gênica , Modelos Logísticos , Mycobacterium tuberculosis/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos
3.
J Hematol Oncol ; 11(1): 62, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29728108

RESUMO

BACKGROUND: Promotor hypermethylation of CpG islands is common in B cell precursor acute lymphoblastic leukemia (BCP-ALL) with mixed lineage leukemia (MLL) gene rearrangements. Hypomethylating agents (HMA) such as azacitidine (AZA) and decitabine (DEC) reduce DNA hypermethylation by incorporation into DNA and were successfully introduced into the clinic for the treatment of myeloid neoplasias. METHODS: Here, we investigated whether HMA induce comparable biological effects in MLL-positive BCP-ALL. Further, efficacy of HMA and concomitant application of cytostatic drugs (cytarabine and doxorubicin) were evaluated on established SEM and RS4;11 cell lines. In addition, promising approaches were studied on BCP-ALL cell line- and patient-derived xenograft models. RESULTS: In general, DEC effects were stronger compared to AZA on MLL-positive BCP-ALL cells. DEC significantly reduced proliferation by induction of cell cycle arrest in G0/G1 phase and apoptosis. Most sensitive to HMA were SEM cells which are characterized by a fast cell doubling time. The combination of low-dose HMA and conventional cytostatic agents revealed a heterogeneous response pattern. The strongest antiproliferative effects were observed when ALL cells were simultaneously exposed to HMA and cytostatic drugs. Most potent synergistic effects of HMA were induced with cytarabine. Finally, the therapeutic potential of DEC was evaluated on BCP-ALL xenograft models. DEC significantly delayed leukemic proliferation in xenograft models as demonstrated longitudinally by non-invasive bioluminescence as well as 18F-FDG-PET/CT imaging. Unexpectedly, in vivo concomitant application of DEC and cytarabine did not enhance the antiproliferative effect compared to DEC monotherapy. CONCLUSIONS: Our data reveal that DEC is active in MLL-positive BCP-ALL and warrant clinical evaluation.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Decitabina/uso terapêutico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamento farmacológico , Animais , Antimetabólitos Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Decitabina/farmacologia , Modelos Animais de Doenças , Rearranjo Gênico , Humanos , Camundongos
4.
Phys Rev Lett ; 84(21): 4822-5, 2000 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-10990807

RESUMO

Radiative recombination (inverse photoionization) is believed to be well understood since the beginning of quantum mechanics. Still, modern experiments consistently reveal excess recombination rates at very low electron-ion center-of-mass energies. In a detailed study on recombination of F6+ and C6+ ions with magnetically guided electrons we explored the yet unexplained rate enhancement, its dependence on the magnetic field B, the electron density n(e), and the beam temperatures T( perpendicular) and T( ||). The excess scales as T(-1/2)( perpendicular) and, surprisingly, as T(-1/2)( ||), increases strongly with B, and is insensitive to n(e). This puts strong constraints on explanations of the enhancement.

5.
Handchir Mikrochir Plast Chir ; 26(2): 80-3, 1994 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-8020852

RESUMO

The surgical success of microvascular free flaps or pedicled flaps depends on the function of the nutritive vessels. Complications such as thrombosis or vessel kinking, are dangerous and may result in flap loss. During the last decade, different methods were tested for their capability of monitoring flap perfusion. We report our preliminary experience with the continuous and non-invasive pulse oximetry by using a special reflection sensor positioned on the surface of the flap.


Assuntos
Sobrevivência de Enxerto/fisiologia , Microcirurgia/instrumentação , Oximetria/instrumentação , Retalhos Cirúrgicos/fisiologia , Adulto , Idoso , Anastomose Cirúrgica , Eletrodos , Feminino , Oclusão de Enxerto Vascular/fisiopatologia , Oclusão de Enxerto Vascular/cirurgia , Humanos , Masculino , Microcirculação/fisiopatologia , Pessoa de Meia-Idade , Oxigênio/sangue , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/cirurgia , Reoperação , Processamento de Sinais Assistido por Computador/instrumentação
6.
Biomed Tech (Berl) ; 37(10): 213-7, 1992 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-1420830

RESUMO

A capacitive sensor was tested for its suitability for measuring relative humidity in an anaesthetic gas circuit. The valvo sensor PH1 was tested using various different anaesthetic gas mixtures. Measuring accuracy was influenced neither by such volatile anaesthetics as isoflurane and halothane, nor by oxygen or nitrous oxide. The response time of the sensor depends on its position within the gas, and in the most favourable case is about 3 minutes. The sensor is readily incorporated within an existing gas circuit. The linearity of the characteristic curve must be corrected by external electronic compensation to avoid measuring problems in the lower humidity range.


Assuntos
Anestesia Endotraqueal/instrumentação , Halotano , Umidade , Isoflurano , Óxido Nitroso , Oxigenoterapia/instrumentação , Desenho de Equipamento , Humanos , Valores de Referência
7.
Dtsch Tierarztl Wochenschr ; 101(5): 207-8, 1994 May.
Artigo em Alemão | MEDLINE | ID: mdl-8013300

RESUMO

A case of porcine malignant hyperthermia (MH) is reported, which occurred during a cardiological animal experiment under general anaesthesia using isoflurane as inhalational anaesthetic. Initially, tachycardia (238 bpm) and a sudden increase of end-exspiratory pCO2 were noticed. Discontinuation of isoflurane followed by administration of dantrolene (7 mg/kg body weight) led to a rapid recovery. Two days later, no difference in clinical state was apparent in comparison with the remaining swine. After regular euthanasia, acute muscle necrosis was seen macroscopically in back and glutaeal muscles, which was confirmed by histological examination. The rise of end-tidal pCO2 was the striking symptom thus allowing the detection of the incipient malignant hyperthermia. Early onset of dantrolene therapy is shown to be sufficient in termination of this hyperacute complication, and may prevent its deleterious outcome. Therefore, the administration of dantrolene should be taken into account in case of porcine MH, especially in time-consuming and costly series of animal experiments.


Assuntos
Anestesia por Inalação/efeitos adversos , Dantroleno/uso terapêutico , Isoflurano , Hipertermia Maligna/veterinária , Doenças dos Suínos/etiologia , Animais , Dióxido de Carbono/sangue , Hipertermia Maligna/tratamento farmacológico , Hipertermia Maligna/etiologia , Suínos , Doenças dos Suínos/tratamento farmacológico
8.
J Chem Ecol ; 17(3): 557-66, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24258806

RESUMO

A series of new sesquiterpene ketones and norsesquiterpene ketones could be identified from the cephalic secretion of females of the cuckoo bee,Nomada lathburiana (K.). The major component proved to be 2,6,10-trimethylundeca-(5E)-2,5,9-trien-4-one. Large amounts of high-boiling-point straight-chain hydrocarbons serve as solvents for the volatile, unstable ketones.

9.
Anaesthesist ; 44(10): 709-11, 1995 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-8533872

RESUMO

A pre-term infant weighing 900 g, gestational age 25 weeks, developed an acute abdomen. Intravenous lines had been inserted previously in the left (silastic catheter) and right (24 G cannula) saphenous veins in the neonatal intensive care unit. During surgical exploration, a perforation of the terminal ileum was found. The operation consisted in partial resection of the perforated ileum with an end-to-end anastomosis and a double-lumen colostomy. Major blood loss during the procedure caused serious haemodynamic problems. Despite transfusion of erythrocyte (100 ml), thrombocytes (75 ml), and albumin (50 ml), the patient developed bradycardia and hypotension. Administration of atropine, adrenaline, and calcium i.v. had no effect. The operation could be finished only with extrathoracic resuscitation. When the drapes were removed, livid, swollen lower limbs raised the suspicion of an acute thrombosis of the inferior vena cava. After insertion of a 24 G i.v. cannula into a vein of the right upper arm, the circulation stabilised after rapid transfusion of 40 ml blood and 25 ml thrombocytes and resuscitation was successful. Paediatricians and anaesthesiologists must consider the risk of thrombosis of the vena cava. If venous lines in the lower limbs are not visible to the anaesthesiologist during the operation, venipuncture of veins of an upper limb is recommended before starting the surgical procedure. Due to the high incidence of vena cava thrombosis caused by central venous lines and the difficulty of peripheral venipuncture in pre-termintanty, a safe venous line should be inserted if necessary by pre-operative venesection.


Assuntos
Complicações Intraoperatórias/fisiopatologia , Trombose/fisiopatologia , Veia Cava Inferior , Transfusão de Sangue , Cateterismo Venoso Central/efeitos adversos , Humanos , Recém-Nascido , Complicações Intraoperatórias/diagnóstico por imagem , Masculino , Ressuscitação , Trombose/diagnóstico por imagem , Ultrassonografia
10.
Schmerz ; 8(1): 51-6, 1994 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-18415455

RESUMO

UNLABELLED: Pain and pain-related sympathoadrenergic reactions (hypertension, tachycardia) accompanied by nausea, vomiting and shivering are the most common side effects of recovery from anaesthesia. The alpha(2)agonist clonidine acts as a sedative, anxiolytic, antihypertensive, antiemetic, antisialogogue and decreases the incidence of shivering. Thus, we studied the effects of intraoperatively administered clonidine on the recovery period and the postoperative analgesic requirements in patients undergoing maxillofacial surgery. METHODS: After approval by the local Ethics Commitee and after informed consent had been given, 40 patients scheduled for elective maxillofacial surgery were included in this double-blind, randomized study. As a supplement to standardized general anaesthesia (isoflurane, N(2)O), the patients received either clonidine 5 mug/kg or placebo during the last hour of the operation. Blood pressure, heart rate, time of recovery, and sedation and pain scores were measured postoperatively. The occurrence of nausea, vomiting or shivering was noted, as were the requirements of piritramide for analgesia, which was administered on demand in titrating dosages, and of nifedipine for systolic blood pressure exceeding 180 mm Hg. RESULTS: The two groups were comparable regarding biometric parameters, ASA-classification and duration of anaesthesia. Clonidinetreated patients were later in opening their eyes (22.5+/-11.9 min vs 17.9+/-10.9; n.s.) and the ability to state their dates of birth returned later (32.2+/-11.6 min vs. 25.7+/-12.8;P<0.05). Pain was more frequent in the placebo group (P<0.05 after 30 min), and there-fore, these patients required much more piritramid (P<0.01). The sedation scores showed no significant differences. No vomiting occurred in the clonidine group, and shivering was less frequent (P<0.01). The placebo group received more nifedipine (P<0.05) because the rate-pressure product was higher (P<0.01). DISCUSSION: Opiates are frequently used as analgesics after maxillofacial surgery, even though their most common side effect-respiratory depression, nausea and vomiting-are particularly dangerous in these patients because of the obstruction of the upper respiratory tract. Self-titration of the opiate dosage on demand can decrease the incidence of serious side effects. Clonidine administered intraoperatively caused a profound reduction in analgesic requirements in this study. Additional opiate administration in the postoperative period was unnecessary in nearly all clonidine-treated patients. The attenuating effect on sympathoadrenergic reactions leads to lowering of the rate-pressure product and may be of advantage for patients suffering from arterial hypertension, angina pectoris or bronchial asthma. The slower emergence from anaesthesia following clonidine administration is probably caused by double-blind study properties preventing full consideration of the decreased isoflurane requirements after clonidine.

11.
Anaesthesia ; 51(2): 151-4, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8779371

RESUMO

Inhaled in low concentrations, nitric oxide (NO) acts as a potent pulmonary vasodilator, but when inhaled in high concentrations NO and its metabolite NO2 are potentially toxic molecules. Thus, an accurate and reproducible measurement of both NO and NO2 is necessary, and changes in NO concentration need to be detected instantly to avoid lung damage (high concentrations) or failure of NO therapy (low concentrations; unnoticed interruption of NO supply). We investigated two electrochemical NO monitors (Sensor Stik 4586 and Dräger PAC II) for accuracy and time constants. Both provided accurate and reproducible results at different NO concentrations. Known NO concentrations (standards: 10, 50, 75 ppm) were detected within a 3% tolerance, and acceptable time constants were seen when NO concentration was abruptly increased from zero to 50 ppm. The display read the final value within 60 s with the Sensor Stik and 11 s with the Dräger PAC II. Significant differences were seen when the NO concentration was rapidly reduced from 50 ppm to zero. The Sensor Stik took more than 2 h to reach zero, whereas the PAC II took 60 s.


Assuntos
Monitoramento de Medicamentos/instrumentação , Óxido Nítrico/análise , Administração por Inalação , Eletroquímica/instrumentação , Estudos de Avaliação como Assunto , Humanos , Óxido Nítrico/administração & dosagem , Reprodutibilidade dos Testes
12.
Anaesthesist ; 45(9): 798-801, 1996 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-8967596

RESUMO

In the presence of completely dry soda lime volatile anaesthetics will decompose to carbon monoxide (CO). In an in vitro study, the absorbent (soda lime, ICI) was dried with a constant gas flow of 11/min oxygen for 120 h. The weight loss during the drying was 17.1%. Two vol% of halothane, enflurane or isoflurane in oxygen was administered with a constant flow of 0.51/min oxygen through the completely dry absorbent. Concentrations of gases were measured before and after the absorbent using mass spectrometry (MGA 1100, Perkin-Elmer) and an electrochemical NO monitor (Mini PAC CO, Dräger). The temperature inside the soda lime was monitored continuously. Shortly after adding the anaesthetic to the oxygen passing through the absorbent, carbon monoxide appeared in the outlet of the soda lime container. The measured peak concentrations varied around 450 ppm (halothane), 3500 ppm (enflurane) and 3800 ppm (isoflurane). The temperature inside the absorbent rose from the ambient temperature (19.8 degrees C) to a maximum of 52.1 degrees C during CO production and decreased when the CO production lowered after approximately 1 h (all anaesthetics). During CO production no measurable concentration of halothane left the absorber. After passing through the absorbent the concentrations of isoflurane and enflurane were slightly lower than the corresponding concentrations in the fresh gas measured before absorption.


Assuntos
Anestésicos Inalatórios/química , Monóxido de Carbono/química , Enflurano/química , Halotano/química , Isoflurano/química , Absorção , Compostos de Cálcio , Gases , Cinética , Espectrometria de Massas , Óxidos , Hidróxido de Sódio
13.
Anaesthesist ; 45(1): 88-94, 1996 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-8678284

RESUMO

UNLABELLED: Following parenteral administration, clonidine has analgesic effects at both cerebral and spinal levels. Patient-controlled analgesia (PCA) makes it possible to determine equipotent dosages of analgesics by relating analgesic consumption per time to the levels of analgesia obtained in comparable patient populations. Therefore, we studied the equipotency ratios of clonidine and piritramide and the incidence of undesired side effects in the treatment of postoperative pain in patients undergoing maxillo-facial surgery. METHODS: After approval of the local ethics committee and informed consent 40 patients (age > 18 year, ASA I-III) were studied. Following randomization, the patients each received a PCA device containing either clonidine (bolus 30 micrograms), or piritramide (bolus 1.5 mg) for treatment of postoperative pain (lockout interval 5 min in both groups). During the postoperative period, pain was determined using a visual analogue scale, while analgesic consumption, sedation, haemodynamic parameters, respiration rate, and the occurrence of undesired side effects were documented additionally. RESULTS: The groups had comparable distributions of biometric data, duration of anaesthesia, and ASA classification. Pain level decreased significantly (P < 0.0001) in both groups during the first 2 h of PCA. Mean arterial pressure and heart rate were lower (P < 0.05) in the clonidine group 4 and 6 h after PCA onset, while the degree of sedation after 2 (P < 0.01) and 6 (P < 0.05) h was higher than in the piritramide group. Nausea and vomiting were more frequent (P < 0.05) in the piritramide group. Both groups showed a wide interpatient variation in analgesic requirement. The equipotency ratio clonidine/piritramid was 1:63.7. CONCLUSION: Intravenous clonidine is a potent analgesic and is suitable or the treatment of postoperative pain following maxillo-facial surgery. The analgesic potency of 150 micrograms clonidine i.v. was equivalent to that of 9.56 mg piritramide i.v. Nausea and vomiting occurred more rarely in the clonidine group, while deeper sedation was observed more frequently than in the piritramide group. Owing to the wide interindividual variation of analgesic consumption, clonidine dosages have to be adjusted to the actual requirements.


Assuntos
Analgesia Controlada pelo Paciente , Analgésicos Opioides/administração & dosagem , Clonidina/administração & dosagem , Dor Pós-Operatória/tratamento farmacológico , Pirinitramida/administração & dosagem , Simpatolíticos/administração & dosagem , Adolescente , Adulto , Idoso , Analgésicos Opioides/efeitos adversos , Clonidina/efeitos adversos , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Pirinitramida/efeitos adversos , Estudos Prospectivos , Simpatolíticos/efeitos adversos
14.
J Chem Ecol ; 17(2): 485-95, 1991 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24258740

RESUMO

The major component of the rectal glandular extract and volatile emission of maleBactrocera cacuminatus is racemic 1,7-dioxaspiro[5.5]undecane. l-Hydroxy-5-nonanone as its open chain form, together with 6-n-butyl-3,4-dihydro-2H-pyran are minor components. 1,7-Dioxaspiro[5.5]undecan-4-ol is present at a low level and is shown to be exclusively the diastereomer with an equatorial hydroxy group by comparison with synthesized samples of both epimers. Examination of the trifiuoroacetate by chiral gas chromatography has established the (4S,6S) stereochemistry (ca. 80% ee). The presence of 1,7-dioxaspiro[5.5]undecan-3-ol, or its isomerization product, 1,6-dioxaspiro[4.5]decan-2-ylmethanol, could not be confirmed. Trapping of the volatiles released by sexually mature male flies at dusk revealed that a number of the glandular components described above are released at mating time. Reexamination of the glandular secretion of sexually mature female olive flies (B. oleae) has failed to confirm the presence of any 1,7-dioxaspiro[5.5]undecanols, with the only volatile component (other than fatty acids) being 1,7-dioxaspiro[5.5]undecane.

15.
J Chem Ecol ; 18(12): 2169-76, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24254865

RESUMO

The major component (>90% of volatiles) of the male rectal glandular extract of the nonpest speciesBactrocera visenda (Hardy) is 3-methyl2-butenyl acetate, with minor components being the isomeric 3-methyl-3-butenyl acetate, the homologous esters, 3-methyl-2-butenyl propanoate and 3-methyl-2-butenyl formate, along with 3-methyl-2-buten-1-ol, 3-methyl-2-butenal, and 3-methylbutyl acetate. None of these compounds has been identified previously from aBactrocera species, supporting the view thatBactrocera visenda is taxonomically distant from otherBactrocera species identified from the Australian mainland. This collection of compounds adds to the known types utilized by dipteran species and emphasizes their extensive biosynthetic capability.

16.
Anaesthesiol Reanim ; 20(6): 162-5, 1995.
Artigo em Alemão | MEDLINE | ID: mdl-8652042

RESUMO

We report on a 19-month-old boy with congenital single atrium. Cardiac catheterization preceding the surgical repair revealed an elevated pulmonary artery pressure of 60/15 mmHg (mean pressure 40 mmHg). Pulmonary flow was 8.4 l/min.m2 and systemic flow was 5.5 l/min.m2. Pulmonary arteriolar resistance was elevated to 4.2 U.m2 with 64% left-right shunt and 25% right-left shunt. Arterial O2-saturation varied around 90%. After surgical repair (insertion of a Goretex patch), the patient required mechanical ventilation with 100% oxygen for adequate oxygenation. Cardiac catheterization was repeated on the first postoperative day. No residual shunts were found. The pulmonary artery pressure was 66/40 mmHg (mean pressure 50 mmHg), systemic arterial pressure was 85/62 mmHg (mean pressure 68 mmHg). Cardiac index was 2.8 l/min.m2, pulmonary vascular resistance was 12 U.m2. After administration of prostacyclin a significant decrease of pulmonary artery pressure was observed, but without changing the ratio between pulmonary and systemic pressure. The AaDO2 varied between 400 and 580 mmHg and the oxygenation-index (PaO2/FiO2) was less than 1.0. In this situation, an attempt with inhaled nitric oxide (NO) was performed. After adding 20 ppm NO to the inspired gas, the AaDO2 decreased significantly from 580 to 270 mmHg and the oxygenation-index (OI) rose from 0.9 to 1.5. The inspired fraction of oxygen could be reduced quickly to 60%. During the next days, the concentration of NO was reduced stepwise to 1 ppm. Finally, the AaDO2 was within the normal range (25-65 mmHg) and the OI rose to a level about 4.0. The FiO2 could be reduced to 30% and nitric oxide therapy could be stopped and the child could be extubated.


Assuntos
Átrios do Coração/anormalidades , Cardiopatias Congênitas/cirurgia , Hipertensão Pulmonar/terapia , Óxido Nítrico/administração & dosagem , Oxigenoterapia , Complicações Pós-Operatórias/terapia , Administração por Inalação , Terapia Combinada , Átrios do Coração/cirurgia , Hemodinâmica/efeitos dos fármacos , Humanos , Lactente , Masculino , Pressão Propulsora Pulmonar/efeitos dos fármacos
17.
Appl Environ Microbiol ; 56(4): 1148-56, 1990 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16348159

RESUMO

A Pseudomonas sp. strain, HH69, and a mixed culture, designated HH27, were isolated by selective enrichment from soil samples. The pure strain and the mixed culture grew aerobically on dibenzofuran as the sole source of carbon and energy. Degradation proceeded via salicylic acid which was branched into the gentisic acid and the catechol pathway. Both salicylic acid and gentisic acid accumulated in the culture medium of strain HH69. The acids were slowly metabolized after growth ceased. The enzymes responsible for their metabolism showed relatively low activities. Besides the above-mentioned acids, 2-hydroxyacetophenone, benzopyran-4-one (chromone), several 2-substituted chroman-4-ones, and traces of the four isomeric monohydroxydiben-zofurans were identified in the culture medium. 2,2',3-Trihydroxybiphenyl was isolated from the medium of a dibenzofuran-converting mutant derived from parent strain HH69, which can no longer grow on dibenzofuran. This gives evidence for a novel type of dioxygenases responsible for the attack on the biarylether structure of the dibenzofuran molecule. A meta-fission mechanism for cleavage of the dihydroxylated aromatic nucleus of 2,2',3-trihydroxybiphenyl is suggested as the next enzymatic step in the degradative pathway.

18.
Phys Rev Lett ; 86(5): 779-82, 2001 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-11177938

RESUMO

Fragmentation patterns for dissociative recombination of the triatomic hydrogen molecular ion H(3)(+) in the vibrational ground state have been measured using the storage ring technique and molecular fragment imaging. A broad distribution of vibrational states in the H(2) fragment after two-body dissociation and a large predominance of nearly linear momentum geometries after three-body dissociation are found. The fragmentation results are directly contrasted with Coulomb explosion imaging data on the initial H(3)(+) geometry, compared to existing wave-packet calculations, and considered in the light of a simple physical picture.

19.
Phys Rev Lett ; 86(18): 4005-8, 2001 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-11328081

RESUMO

The dissociative recombination of LiH+ ions with low-energy electrons is observed at a storage ring and the final states are analyzed using fragment imaging and field ionization techniques. The rate coefficient is found to be larger than its estimated value used in astrophysical models. Mostly the highest energetically possible Rydberg states of the lithium atom are populated by the reaction, indicating a common trend for molecular recombination via the noncrossing mode.

20.
Phys Rev Lett ; 91(19): 190403, 2003 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-14611572

RESUMO

An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7Li+ ions at v=0.064c have been measured in the forward and backward direction to an accuracy of Deltanu/nu=1 x 10(-9) using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 x 10(-7) for deviations from the time dilation factor gamma(SR)=(1-v2/c2)(-1/2).

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA