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1.
Phys Rev Lett ; 128(19): 197702, 2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35622049

RESUMO

We performed microwave spectroscopy of an InAs nanowire between superconducting contacts implementing a finite-length, multichannel Josephson weak link. Certain features in the spectra, such as the splitting by spin-orbit interactions of the transition lines among Andreev states, have been already understood in terms of noninteracting models. However, we identify here additional transitions, which evidence the presence of Coulomb interactions. By combining experimental measurements and model calculations, we reach a qualitative understanding of these very rich Andreev spectra.

2.
Phys Rev Lett ; 125(7): 077701, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32857526

RESUMO

Spectral properties of a quantum circuit are efficiently read out by monitoring the resonance frequency shift it induces in a microwave resonator coupled to it. When the two systems are strongly detuned, theory attributes the shift to an effective resonator capacitance or inductance that depends on the quantum circuit state. At small detuning, the shift arises from the exchange of virtual photons, as described by the Jaynes-Cummings model. Here we present a theory bridging these two limits and illustrate, with several examples, its necessity for a general description of quantum circuits readout.

3.
Sci Total Environ ; 737: 139361, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32534266

RESUMO

Peat soils are typical deposits characterizing wetlands and reclaimed farmlands. They are important carbon reservoirs and when degraded (e.g., erosive processes, fires, draining and plowing) massive carbon dioxide volumes are released. This leads to increase greenhouse effect and induce serious land subsidence. Thus, mapping the volume of peat deposits is crucial in order to estimate the carbon mass and the potential release of carbon dioxide and consequent loss in soil elevation. Despite the importance of such estimations, forecasting and quantifying the peat thickness is still a challenge. Direct sediment coring provides local information that is difficult to extend to large territories. Indirect geophysical methods are unable to resolve lithological contrasts in the presence of saltwater contamination in coastal areas. In this work, we show the results obtained using two contact-less electromagnetic methods for the characterization of peat deposits in a peatland site of the Venice coastland, Italy. Specifically, a multi-frequency portable instrument (FDEM) and an airborne time-domain electromagnetic one (AEM), known for their very high and relatively low vertical resolution respectively, were used to collect data over a former wetland then reclaimed for agricultural purposes. Additional electrical resistivity tomography (ERT) data are used together with sediment core data to assess the effectiveness and accuracy of the contact-less methods. Results show that both FDEM and AEM are very effective in detecting the presence of the peat layer, despite its low thickness (<2 m) and the high electro-conductive subsoil because of saltwater contamination. However, the AEM method overestimated the peat thickness while the FDEM could accurately resolve the peat thickness even where the layer was thinner than 1 m. When compared to the electrical features extracted from the ERT, discrepancies are on average lower than 30%; when compared to the borehole data, discrepancies are on average slightly higher than 6%.

4.
J Phys Condens Matter ; 31(46): 465602, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31357183

RESUMO

We study the transport through a molecular junction exhibiting interference effects. We show that these effects can still be observed in the presence of molecular vibrations if Coulomb repulsion is taken into account. In the Kondo regime, the conductance of the junction can be changed by several orders of magnitude by tuning the levels of the molecule, or displacing a contact between two atoms, from nearly perfect destructive interference to values of the order of 2e 2/h expected in Kondo systems. We also show that this large conductance change is robust for reasonable temperatures and voltages for symmetric and asymmetric tunnel couplings between the source-drain electrodes and the molecular orbitals. This is relevant for the development of quantum interference effect transistors based on molecular junctions.

5.
Osteoporos Int ; 30(2): 507-511, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30191258

RESUMO

There is limited research which examines health concerns of individuals with osteogenesis imperfecta (OI). Discussion groups with leaders of the adult OI community identified a broad range of medical priorities beyond fractures and brittle bones. Our work underscores the need to include patient-reported outcomes in rare bone disease research. INTRODUCTION: Osteogenesis imperfecta (OI) is a rare genetic disorder affecting collagen protein leading to brittle bones and a number of other medical complications. To date, there is limited research which examines the life-long process of aging with this rare disease, much less the perspective of individuals with OI. METHODS: In order to explore and prioritize health concerns that adults with OI feel have been inadequately addressed in health care and research, investigators held discussions with leaders from the global adult OI community. The meetings were held in August 2017 at the 13th International Conference on OI in Oslo, Norway as part of the preconference seminar "Patient Participation in OI Research". Investigators were part of the Brittle Bone Disease Consortium (BBDC), a multicenter research program devoted to the study of OI, and their focus was on patient-reported outcomes (PRO). RESULTS: Participants noted that while fractures and brittle bones are the most common feature of OI, a number of body systems are under-studied in this disorder. They particularly emphasized breathing, hearing, and the effects of aging as primary concerns that researchers and physicians may not fully understand or address. Other areas included pain, gastrointestinal problems, mental health, nutrition, menopause/pregnancy, and basilar invagination. Participants also emphasized that they must be informed of study results. They underscored that outcome measures incorporated into future drug trials must look beyond fractures and consider the whole patient. CONCLUSIONS: This work will help guide the incorporation of PROs into the next phase of the BBDC Natural History Study of OI and underscores the importance of including PROs in the study of rare diseases.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Osteogênese Imperfeita/psicologia , Doenças Raras/psicologia , Adulto , Envelhecimento , Pesquisa Biomédica/métodos , Pesquisa Participativa Baseada na Comunidade/métodos , Feminino , Fraturas Espontâneas/etiologia , Fraturas Espontâneas/psicologia , Perda Auditiva/etiologia , Perda Auditiva/psicologia , Humanos , Masculino , Osteogênese Imperfeita/complicações , Osteogênese Imperfeita/reabilitação , Medidas de Resultados Relatados pelo Paciente , Psicometria , Qualidade de Vida , Doenças Raras/complicações , Doenças Raras/reabilitação , Doenças Respiratórias/etiologia , Doenças Respiratórias/psicologia
6.
Osteoporos Int ; 29(9): 2101-2109, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29858634

RESUMO

The American Orthopaedic Association initiated the Own the Bone (OTB) quality improvement program in 2009. Herein we show that the data collected through this program is similar to that collected in other large studies. Thus, the OTB registry functions as an externally valid cohort for studying fragility fracture patients. INTRODUCTION: The American Orthopedic Association initiated the Own the Bone (OTB) quality improvement program in 2009 to improve secondary prevention of fragility fractures. In this study, we present a summary of the data collected by the OTB program and compare it to data from other large fragility fracture registries with an aim to externally validate the OTB registry. METHODS: The OTB registry contained 35,038 unique cases of fragility fracture as of September, 2016. We report the demographics, presenting fracture characteristics, past fracture history, and bone mineral density (BMD) data and compare these to data from large fragility fracture studies across the world. RESULTS: Seventy-three percent of the patients in the OTB registry were female, Caucasian, and post-menopausal. In 54.4% of cases, patients had a hip fracture; spine fractures were the second most common fracture type occurring in 11.1% of patients. Thirty-four percent of the patients had a past history of fragility fracture, and the most common sites were the spine and hip. The average femoral neck T-score was - 2.06. When compared to other studies, the OTB database showed similar findings with regard to patient age, gender, race, BMI, BMD profile, prior fracture history, and family history of fragility fractures. CONCLUSION: OTB is the first and largest multi-center voluntary fragility fracture registry in the USA. The data collected through the OTB program is comparable to that collected in international studies. Thus, the OTB registry functions as an externally valid cohort for further studies assessing the clinical characteristics, interventions, and outcomes achieved in patients who present with a fragility fracture in the USA.


Assuntos
Fraturas por Osteoporose/epidemiologia , Melhoria de Qualidade , Sistema de Registros , Prevenção Secundária/normas , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/fisiologia , Conservadores da Densidade Óssea/uso terapêutico , Bases de Dados Factuais , Uso de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/fisiopatologia , Fraturas por Osteoporose/prevenção & controle , Distribuição por Sexo , Estados Unidos/epidemiologia
7.
Osteoporos Int ; 27(12): 3615-3626, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27497815

RESUMO

Cutaneous skeletal hypophosphatemia syndrome (CSHS), caused by somatic RAS mutations, features excess fibroblast growth factor-23 (FGF23) and skeletal dysplasia. Records from 56 individuals were reviewed and demonstrated fractures, scoliosis, and non-congenital hypophosphatemia that in some cases were resolved. Phosphate and calcitriol, but not skin lesion removal, were effective at controlling hypophosphatemia. No skeletal malignancies were found. PURPOSE: CSHS is a disorder defined by the association of epidermal and/or melanocytic nevi, a mosaic skeletal dysplasia, and an FGF23-mediated hypophosphatemia. To date, somatic RAS mutations have been identified in all patients whose affected tissue has undergone DNA sequencing. However, the clinical spectrum and treatment are poorly defined in CSHS. The purpose of this study is to determine the spectrum of the phenotype, natural history of the disease, and response to treatment of hypophosphatemia. METHODS: Five CSHS subjects underwent prospective data collection at clinical research centers. A review of the literature identified 45 reports that included a total of 51 additional patients, in whom the findings were compatible with CSHS. Data on nevi subtypes, bone histology, mineral and skeletal disorders, abnormalities in other tissues, and response to treatment of hypophosphatemia were analyzed. RESULTS: Fractures, limb deformities, and scoliosis affected most CSHS subjects. Hypophosphatemia was not present at birth. Histology revealed severe osteomalacia but no other abnormalities. Skeletal dysplasia was reported in all anatomical compartments, though less frequently in the spine; there was no clear correlation between the location of nevi and the skeletal lesions. Phosphate and calcitriol supplementation was the most effective therapy for rickets. Convincing data that nevi removal improved blood phosphate levels was lacking. An age-dependent improvement in mineral abnormalities was observed. A spectrum of extra-osseous/extra-cutaneous manifestations that included both benign and malignant neoplasms was present in many subjects, though osteosarcoma remains unreported. CONCLUSION: An understanding of the spectrum, natural history, and efficacy of treatment of hypophosphatemia in CSHS may improve the care of these patients.


Assuntos
Hipofosfatemia/diagnóstico , Hipofosfatemia/patologia , Osso e Ossos/patologia , Criança , Pré-Escolar , Feminino , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos , Humanos , Hipofosfatemia/terapia , Lactente , Masculino , Nevo Pigmentado/etiologia , Osteomalacia/etiologia , Fosfatos , Estudos Prospectivos , Neoplasias Cutâneas/etiologia
8.
Science ; 349(6253): 1199-202, 2015 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-26359397

RESUMO

Coherent control of quantum states has been demonstrated in a variety of superconducting devices. In all of these devices, the variables that are manipulated are collective electromagnetic degrees of freedom: charge, superconducting phase, or flux. Here we demonstrate the coherent manipulation of a quantum system based on Andreev bound states, which are microscopic quasi-particle states inherent to superconducting weak links. Using a circuit quantum electrodynamics setup, we performed single-shot readout of this Andreev qubit. We determined its excited-state lifetime and coherence time to be in the microsecond range. Quantum jumps and parity switchings were observed in continuous measurements. In addition to having possible quantum information applications, such Andreev qubits are a test-bed for the physics of single elementary excitations in superconductors.

9.
J Phys Condens Matter ; 27(33): 335601, 2015 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-26235364

RESUMO

We calculate the spectral density and occupations of a system of two capacitively coupled quantum dots, each one connected to its own pair of conducting leads, in a regime of parameters in which the total couplings to the leads for each dot Γ(i) are different. The system has been used recently to perform pseudospin spectroscopy by controlling independently the voltages of the four leads. For an odd number of electrons in the system, equal coupling to the leads Γ1 = Γ2, equal dot levels E1 = E2 and sufficiently large interdot repulsion U12 the system lies in the SU(4) symmetric point of spin and pseudospin degeneracy in the Kondo regime. In the more realistic case Γ1 ≠ Γ2, pseudospin degeneracy is broken and the symmetry is reduced to SU(2). Nevertheless, we find that the essential features of the SU(4) symmetric case are recovered by appropriately tuning the level difference δ = E2 - E1. After this tuning, the system behaves as an SU(4) Kondo one at low energies. Our results are relevant for experiments which look for signatures of SU(4) symmetry in the Kondo regime of similar systems.

10.
J Phys Condens Matter ; 26(47): 474208, 2014 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-25351409

RESUMO

We describe and characterize a microwave setup to probe the Andreev levels of a superconducting atomic contact. The contact is part of a superconducting loop inductively coupled to a superconducting coplanar resonator. By monitoring the resonator reflection coefficient close to its resonance frequency as a function of both flux through the loop and frequency of a second tone we perform spectroscopy of the transition between two Andreev levels of highly transmitting channels of the contact. The results indicate how to perform coherent manipulation of these states.

11.
Am J Transplant ; 13(11): 2996-3002, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24119046

RESUMO

The effect of organ-recipient gender match on pediatric heart transplant mortality is unknown. We analyzed the effects of gender and donor-recipient gender matching. Based on Organ Procurement and Transplant Network data, we performed a historical cohort study in a population of 3630 heart transplant recipients less than 18 years old. We compared unadjusted and adjusted mortality by recipient gender, donor gender and between gender-matched and gender-mismatched recipients. Female recipients had decreased survival compared to male recipients (unadjusted hazard ratio [HR] 1.16, confidence interval [CI] 1.02-1.31; p = 0.020). Organ-recipient gender mismatch did not affect mortality for either male or female recipients, though gender-mismatched females had the worst survival compared to gender-matched males, who had the best survival (unadjusted HR 1.26, CI 1.07-1.49; p = 0.005). After adjustment for other risk factors affecting transplant mortality, female recipients had decreased survival compared to male recipients (HR 1.27, CI 1.12-1.44; p = 0.020) and gender matching had no effect. In conclusion, gender mismatch alone did not increase long-term mortality for pediatric heart transplant recipients. However, there may be additive effects of gender and gender matching affecting survival. There are insufficient data at this time to support that recipient and donor gender should affect heart allocation in children.


Assuntos
Sobrevivência de Enxerto , Cardiopatias/cirurgia , Transplante de Coração/mortalidade , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Seguimentos , Cardiopatias/mortalidade , Humanos , Masculino , Prognóstico , Fatores Sexuais , Taxa de Sobrevida , Obtenção de Tecidos e Órgãos
12.
J Phys Condens Matter ; 24(36): 365301, 2012 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-22892707

RESUMO

Starting from exact eigenstates for a symmetric ring, we derive a low-energy effective generalized Anderson Hamiltonian which contains two spin doublets with opposite momenta and a singlet for the neutral molecule. For benzene, the singlet (doublets) represent the ground state of the neutral (singly charged) molecule. We calculate the non-equilibrium conductance through a benzene molecule, doped with one electron or a hole (i.e. in the Kondo regime), and connected to two conducting leads at different positions. We solve the problem using the Keldysh formalism and the non-crossing approximation. When the leads are connected in the para position (at 180°), the model is equivalent to the ordinary impurity Anderson model and its known properties are recovered. For other positions, there is a partial destructive interference in the co-tunneling processes involving the two doublets and, as a consequence, the Kondo temperature and the height and width of the central peak (for bias voltage V(b) near zero) of the differential conductance G = dI/dV(b) (where I is the current) are reduced. In addition, two peaks at finite V(b) appear. We study the position of these peaks, the temperature dependence of G and the spectral densities. Our formalism can also be applied to carbon nanotube quantum dots with intervalley mixing.

13.
Benef Microbes ; 1(1): 75-80, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21831752

RESUMO

We aimed to determine the minimum inhibitory concentrations (MICs) of Lactobacillus rhamnosus (n=75) strains, to study their antibiotic resistance genes with microarray, and to assess the microbiological cut-off values of tested antimicrobial agents. L. rhamnosus strains were tested with agar dilution, broth microdilution and Etest methods for ampicillin, clindamycin, erythromycin, gentamicin, streptomycin, and tetracycline using specific LSM medium. Most of the L. rhamnosus strains were found phenotypically susceptible to all six antibiotics tested. Four of the strains were phenotypically multiresistant, three strains to clindamycin, erythromycin and streptomycin and one strain to streptomycin and tetracycline. Some of the resistant (n=8) and susceptible (n=5) strains were further studied with a microarray method to reveal the antibiotic resistance genes behind the phenotypic resistances. From our experience, we recommend that microbiological cut-off values should be proposed according to the method used.


Assuntos
Antibacterianos/farmacologia , Lacticaseibacillus rhamnosus/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana , Lacticaseibacillus rhamnosus/genética , Lacticaseibacillus rhamnosus/metabolismo , Testes de Sensibilidade Microbiana
14.
Plant Dis ; 91(4): 463, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30781203

RESUMO

The recent changes of the European Common Agricultural Policy and the market needs of oleaginous crops for energy purposes caused a renewed increase of sunflower (Helianthus annuus L.) cultivation in Italy. During 2006, surveys on approximately 92 ha of Umbrian (central Italy) sunflower fields were carried out for monitoring distribution and race variability of the pathogen. Twelve fields planted with commercial hybrids were surveyed. Downy mildew was only observed in five fields, with 2 to 3% of disease incidence. Systemic mildewed plants showed stunting, leaf chlorosis, and sporulation on the underside of leaf surface. Pathogen inocula were directly recovered from infected leaves by brushing the fungal structures or after infected leaves were incubated in a humid chamber at 18 to 20°C in the dark for 24 to 48 h. After increasing initial inocula on the suscpetible cv. Ala, race identification of four isolates was determined by the reaction of three standard sets of nine differential sunflower lines using a triplet code (3). Thirty to forty pregerminated seeds for each differential line (three replicates per line) were inoculated by the whole-seedling immersion technique (1). After 12 days, plants were maintained at 20°C and 100% relative humidity for 24 to 48 h to enhance pathogen sporulation and evaluate for susceptible (sporulation on cotyledons and/or first true leaves) or resistance (absence of sporulation or weak sporulation only on cotyledons) reactions. Inoculation tests were performed twice. The isolates were also evaluated for their sensitivity to metalaxyl-M (Apron XL 31.8%) used at the Italian registered rate (1.05 g of a.i. per kg of seed). Treated and untreated seeds of cv. Ala (50 seeds per pot with three replicates) were sown into pots filled with a sterilized sandy-loam mixture (1:1, vol/vol). Five days after sowing, soil drench inoculation was performed by spreading over the pots (80 ml per pot) a zoosporangia suspension (1 to 2 × 104 zoosporangia per ml) of each isolate. Disease incidence (DI) was determined by counting the number of uninfected and infected plants (sporulation on cotyledons and/or true leaves). Hypocotyls of plants that seemed uninfected were cut into sections (2 to 3 cm long) and placed in a humid chamber to allow pathogen sporulation. The experiments were performed twice. Three isolates were characterized as race 700 and one as a mixture of races 700 and 704. Race 700 is more widespread in Italy, whereas race 704 was reported in France in 2002 (2). All Plasmopara helianthi isolates produced 84 to 89% infection on plants from untreated seeds, whereas DI from fungicide treated seeds was significantly lower (8 to 17%). To our knowledge, this is the first report of race 704 in Italy. All field isolates were also metalaxyl-M sensitive as already reported in other European countries (4). References: (1) T. J. Gulya et al. Helia 14:11, 1991. (2) E. Mestries. Oleoscope 83:13, 2005. (3) M. L. Molinero et al. Plant Dis. 86:736, 2002. (4) M. L. Molinero et al. Plant Dis. 87:749, 2003.

15.
Parasitology ; 134(Pt 4): 511-22, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17169165

RESUMO

Leishmania mutants have contributed greatly to extend our knowledge of this parasite's biology. Here we report the use of the mariner in vitro transposition system as a source of reagents for shuttle mutagenesis and targeted disruption of Leishmania genes. The locus-specific integration was achieved by the disruption of the subtelomeric gene encoding a DNA-directed RNA polymerase III subunit (RPC2). Further inactivation of RPC2 alleles required the complementation of the intact gene, which was transfected in an episomal context. However, attempts to generate a RPC2 chromosomal null mutant resulted in genomic rearrangements that maintained copies of the intact locus in the genome. The maintenance of the RPC2 chromosomal locus in complemented mutants was not mediated by an increase in the number of copies and did not involve chromosomal translocations, which are the typical characteristics of the genomic plasticity of this parasite. Unlike the endogenous locus, the selectable marker used to disrupt RPC2 did not display a tendency to remain in its chromosomal location but was targeted into supernumerary episomal molecules.


Assuntos
Leishmania major/genética , Mutagênese/genética , Mutação/genética , RNA Polimerase III/genética , Telômero/genética , Animais , Linhagem Celular , Regulação da Expressão Gênica , Genes Essenciais/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , RNA Polimerase III/metabolismo
17.
Acta Otorhinolaryngol Ital ; 26(4): 219-21, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18236639

RESUMO

Extracranial involvement of the recurrent laryngeal nerve and the hypoglossal nerve is known as Tapia's syndrome. Ipsilateral paralysis of the vocal cord and tongue is present. Lesion of these nerves may be a rare complication of airway management. Herein, a case of Tapia's Syndrome complicating transoral intubation during general anaesthesia in a rhinoplasty operation, together with a review of pertinent literature to evaluate the incidence and the possible pathogenic mechanism of the lesion. There are recent reports in the literature on mono or bilateral paralysis of the XII or laryngeal recurrent nerve after use of laryngeal mask with a pathogenic mechanism of compression. Furthermore, there are reports, following oro-tracheal intubation, of recurrent laryngeal paralysis, likely legacies to the compression of the anterior branch of inferior laryngeal nerve by the cuff of the oro-tracheal tube against the postero-medial part of the thyroid cartilage. Hypoglossal nerve damage could be caused by a stretching of the nerve against the greater horn of the hyoid bone by a laryngeal mask or oro-tracheal tube or compression of the posterior part of the laryngoscope or oro-tracheal tube. In our case, the lesion probably occurred as the result of a two-fold compressive mechanism: on one hand, compression by the cuff of the endo-tracheal tube due to excessive throat pack in the oro-pharynx; on the other hand a prolonged stretching mechanism of these nerves may have occurred due to excessive anterior and lateral flexion of the head. From the data reported in the literature, as in our case, complete recovery of function is generally achieved within the first six months. This progressive recovery of function suggests nerve damage of a neuro-praxic type, which is typical of compression injury. In conclusion, the response of this rare complication confirms the importance not only of the position of the head and patient on the operating table but also the meticulous and correct performance of the routine manoeuvres of airway management.


Assuntos
Anestesia Geral/métodos , Doenças do Nervo Hipoglosso/etiologia , Complicações Pós-Operatórias , Rinoplastia , Paralisia das Pregas Vocais/etiologia , Adulto , Terapia Combinada , Feminino , Humanos , Doenças do Nervo Hipoglosso/complicações , Doenças do Nervo Hipoglosso/terapia , Fonoterapia , Síndrome , Vitaminas/uso terapêutico , Paralisia das Pregas Vocais/complicações , Paralisia das Pregas Vocais/terapia
18.
Food Addit Contam ; 22(6): 541-8, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16019827

RESUMO

The levels of phosphorous acid residues in apples after foliar fertilization with P fertilizers and after treatment with a phosphonate fungicide (Fosetyl-Al) were determined and compared. Two field trials and a glasshouse experiment, using different genotypes and plants of different age, were carried out and monitored over a three-year period. Phosphorous acid residues were found in apples after application of foliar P fertilizers. Concentrations of the residues ranged between 0.02 and 14 mg kg(-1) depending on the phosphorous acid content in the fertilizer used and the plant size and yield. The treatments induced an accumulation of the residue in the course of the experiments, which in some cases reached a level exceeding the maximum limit set by EU legislation. Residues were also detected in other plant organs, i.e., roots and buds. Plants treated with Fosetyl-Al contained phosphorous acid residues in their fruits and buds two years after the suspension of the treatment, suggesting a long-term persistence of the substance in plant storage organs. A second experiment, involving treatment of trees with seven foliar fertilizers of different composition, also induced accumulation of phosphorous acid residues in fruits. It is concluded that a wide array of foliar products containing phosphorous acid, even as a minor component, could mimic the residue effect of phosphonate fungicide treatments.


Assuntos
Resíduos de Drogas/análise , Fertilizantes/análise , Contaminação de Alimentos/análise , Malus/química , Ácidos Fosforosos/análise , Resíduos de Drogas/farmacocinética , Análise de Alimentos/métodos , Fungicidas Industriais , Compostos Organofosforados , Resíduos de Praguicidas/análise , Ácidos Fosforosos/farmacocinética , Estações do Ano , Árvores/metabolismo
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