Biomedical subjects

G Montaldo

Publications and source records attributed to G Montaldo.

15 recordsLinked to original sources

PubMed2004

Time reversal of electromagnetic waves.

We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-micros electromagnetic pulse at a central frequency of 2.45 GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge to its initial source and is compressed in time. The quality of focusing is determined by the frequency bandwidth and the spectral correlations of the field within the cavity.

Journal Article↗

PubMed2001

[Imported myiasis: 7 cases of cutaneous parasitism caused by Dermatobia hominis flie larvas].

Myiasis is the parasitism of organs and tissues of warm-blooded vertebrates by flies larvae. D hominis is a flie geographically restricted to tropical America from Mexico to northern Argentina. The adult flie, which is not hematophagous, needs to put its eggs on the abdominal surface of hematophagous arthropods which serve as carriers of future larvae which are deposited on the skin of the hosts (mammals, birds and accidentally men) when biting. Seven patients (two females) aged 7 to 35 years old, of different nationalities, recalled receiving mosquito bites, after staying in tropical American areas in the previous forty days. They presented furuncle-like lesions in exposed surfaces of the body. These lesions, 2-3 cm long, pruritic and mildly tender, broke and released a serous or serohematic fluid. Through the resulting opening, it was possible to partially observe the larva. Larvae were extracted by manual pressure (4) or surgical incision (3) and identified as D hominis larvae. Diagnosis of dermatobiasis, an imported myiasis, must be based on the characteristics of lesions and the previous residence in endemic areas of America.

Adult↗

PubMed1991

Community- and hospital-acquired respiratory syncytial virus infections in Chile.

Nasopharyngeal aspirates were obtained on admission from 614 patients younger than 2 years of age who were hospitalized in a ward for acute respiratory infections from June 1988 through October, 1989, in Santiago, Chile. Patients in two rooms were followed during the cold seasons by sampling aspirates every other day during the child's entire hospital stay. Clinical features were recorded daily. Indirect monoclonal immunofluorescent assay and isolation in HEp-2 were used for respiratory syncytial virus (RSV) diagnosis. The mean RSV detection rate was 39% at the time of admission, ranging from 8% in April, 1989, to 62% in July, 1988. During the cold months 43 of 288 (15%) nosocomial RSV cases were detected. Pneumonia and wheezing bronchitis were the principal diagnoses of both groups admitted, whether they were shedding RSV or not. It is concluded that RSV plays a major role in admissions for acute respiratory infections, as well as in nosocomial infections, in Santiago. Because clinical features do not allow one to differentiate viral from bacterial acute respiratory infections, the importance of rapid viral diagnosis is emphasized.

Chile↗

PubMed1989

[Diagnosis of sexually transmitted diseases in Chilean pregnant adolescents].

We searched in 100 healthy pregnant women by isolation, the presence of Neisseria gonorrhoeae, Herpes simplex, Mycoplasma hominis, Ureaplasma urealyticum and Chlamydia trachomatis. Blood was also taken for examination of specific antibodies to these microorganisms. We studied only for antibodies titled Cytomegalovirus (CMV), Treponema pallidum and Human Immunodeficiency Virus, and Condyloma acuminatum by cervical cytology. In 85 adolescents we found 5 (6%) patients with C. trachomatis, four of these patients had another microorganism added, one with N. gonorrhoeae, M. hominis and U. Urealyticum, one with U. urealyticum and the last two with M. hominis and U. urealyticum, In relation to Mycoplasmas 69 (81%) out of 85 had Mycoplasmas, 4 (5%) had M. hominis, 46 (54%) U. urealyticum and 19 (22%) patients had both. The seropositivity to CMV was 96.25%. We didn't find any other microorganism. We concluded that the rate of STD in chilean pregnant adolescent women is high, especially with no traditional bacteria.

Adolescent↗

PubMed1976