Biomedical subjects

S Paganelli

Publications and source records attributed to S Paganelli.

5 recordsLinked to original sources

PubMed2004

Teleportation on a quantum dot array.

We present a model of quantum teleportation protocol based on a double quantum dot array. The unknown qubit is encoded using a pair of quantum dots, with one excess electron, coupled by tunneling. It is shown how to create a maximally entangled state using an adiabatically increasing Coulomb repulsion between different dot pairs. This entangled state is exploited to perform teleportation again using an adiabatic coupling between itself and the incoming unknown state. Finally, a sudden separation of Bob's qubit allows a time evolution of Alice's, which amounts to a modified version of standard Bell measurement. A transmission over a long distance could be obtained by considering the entangled state of a chain of N coupled double quantum dots. The system is shown to be increasingly robust with N against decoherence due to phonons.

Journal Article↗

PubMed2002

Non-invasive first trimester fetal gender assignment in pregnancies at risk for X-linked recessive diseases.

OBJECTIVES: Prenatal diagnosis in families affected by X-linked recessive disorders should ideally be limited to the subjects at increased risk, i.e. male fetuses, in order to avoid the risk of fetal loss due to the invasive procedure in healthy female fetuses. The aim of the study was to assess the fetal sex within the first trimester of gestation by two non-invasive approaches, using ultrasonography and a molecular analysis of fetal DNA extracted from whole maternal blood with specific markers, in order to avoid invasive sampling in female fetuses. METHODS: A total number of 18 fetuses at risk for an X-linked recessive disease were included in the present investigation. Maternal peripheral blood was analysed between 7 and 12 weeks of gestation by nested PCR for the detection of fetal DNA and the prediction of fetal gender. In addition, when the biparietal diameter (BPD) was between 21 and 23 mm, an ultrasonographic examination was carried out to assess the fetal gender. CVS was then performed in male fetuses only. RESULTS: Fetal gender was correctly assigned by ultrasonography between 21 and 23 mm of BPD in all the cases studied, whereas DNA extracted from whole maternal blood accurately predicted the gender in all the female cases (10), but failed in 4 out of 8 male fetuses, erroneously assigned as females. CONCLUSION: The present study shows that sonography is able to accurately predict the fetal gender within the first trimester of pregnancy, whereas the molecular analysis of DNA extracted from whole maternal blood is biased by false-Y-negative results in 50% of the cases.

Chorionic Villi Sampling↗

PubMed2001

Sonographic early fetal gender assignment: a longitudinal study in pregnancies after in vitro fertilization.

OBJECTIVES: A longitudinal evaluation by sonography of external genitalia in human embryos/early fetuses with a known time from fertilization is lacking. Our aim was to assign by sonographic evaluation of external genitalia the early fetal gender in a cohort of pregnancies after in vitro fertilization. Sonographic examinations were performed in each case in three subsequent sessions over a period of time early in gestation in order to establish a temporal threshold, expressed in terms of days from fertilization, at which absolute accuracy in gender prediction is achievable. METHODS: Thirty-two fetuses were included in this prospective longitudinal study. Each was examined three times for gender assignment. The first observation was performed between 65 and 69 days from fertilization, the second between 70 and 74 days and the third between 75 and 79 days. Transvaginal and/or transabdominal sonography was used to detect the 'sagittal sign' as a marker of fetal gender. The results of ultrasound examinations were compared with gender at birth or with karyotype obtained from amniotic fluid cells or chorionic villus sampling. RESULTS: Fetal gender assignment was feasible in 29 out of 32 fetuses (90%) at the first examination and in all cases at the second and third examinations. Fetal gender prediction was correct in 76% of cases in which fetal gender was assigned (22/29) at the first examination; accuracy for males was 46% (6/13) and for females 100% (16/16). At the second and third examinations, accuracy for gender prediction achieved 100% for both genders. Concerning the temporal threshold, absolute accuracy in gender prediction was achieved at 69 days from fertilization, corresponding to 11+6 weeks based on the last menstrual period. CONCLUSION: This study provides important information about the earliest stage, expressed in terms of days from fertilization, at which it is possible to make a certain diagnosis of fetal gender by sonography.

Female↗

PubMed2000

Seminal plasma nitrite/nitrate and intratesticular Doppler flow in fertile and infertile subjects.

The objective of the present study was prospectively to evaluate the role of nitric oxide (NO) in modulating intratesticular blood flow and sperm function. A total of 56 males, undergoing assisted reproduction, were divided into three groups according to semen analysis: (i) normozoospermic (n = 16); (ii) oligozoospermic (n = 21); and (iii) azoospermic (n = 19). All the subjects were submitted to hormone analysis [luteinizing hormone, follicle stimulating hormone (FSH), growth hormone, testosterone, androstenedione, insulin], and to ultrasonographic (testicular volume) and Doppler (transmediastinal artery) evaluations. Plasma and seminal plasma nitrite/nitrate concentrations, and plasma insulin-like growth factor-I were assayed. All 56 patients completed the study. In normozoospermic patients, significantly greater testicular volume, lower transmediastinal resistances, and higher seminal plasma nitrite/nitrate concentrations were observed in comparison with both oligo- and azoospermic subjects. Testicular volume was inversely correlated with plasma FSH (r = -0.589; P = 0.005) and pulsatility index of transmediastinal artery (r = -0.402; P = 0.049). Furthermore, the seminal plasma nitrite/nitrate concentrations were inversely correlated with pulsatility index of transmediastinal artery (r = -0.511; P = 0.015). It was concluded that NO is involved in vascular modulation of testicular vessels and ultimately in sperm output.

Adult↗

PubMed1991

The asymmetric hydroformylation in the synthesis of pharmaceuticals.

The asymmetric hydroformylation reaction represents a potential powerful synthetic tool for the preparation of large number of different chiral products to be used as precursors of several organic compounds endowed with therapeutic activity. Essential and nonessential amino acids, 2-arylpropanoic acids, aryloxypropyl- and beta-phenylpropylamines, modified beta-phenylethylamines, pheniramines, and other classes of pharmaceuticals are available through enantioselective oxo-reaction of appropriate functionalized olefins; this process is catalyzed by rhodium or platinum complexes with chiral ligands, mainly chelating phosphines, and sometimes affords very high enantiomeric excesses. Furthermore, the application of many simple optically active aldehydes arising from asymmetric hydroformylation as chiral building blocks for the synthesis of complex pharmacologically active molecules such as antibiotics, peptides, antitumor macrocycle compounds, and prostaglandins is conveniently emphasized. The possibility of a future application of this asymmetric process for the production of many synthons to obtain other valuable pharmaceuticals is widely discussed too.

Amines↗