Reduction of the scanning time by total variation minimization reconstruction for X-ray tomography in a SEM.

Total variation minimization is applied to the particular case of X-ray tomography in a scanning electron microscope. To prove the efficiency of this reconstruction method, noise-free and noisy data based on the Shepp & Logan phantom have been simulated. These simulations confirm that Total variation minimization-reconstruction algorithm better manages data containing low number of projections with respect to simultaneous iterative reconstruction technique or filtered backprojection, even in the presence of noise. The algorithm has been applied to real data sets, with a low angular sampling and a high level of noise. Two samples containing micro-interconnections have been analyzed and 3D reconstructions show that Total variation minimization-based algorithm performs well even with 60 projections in order to properly recover a 500 nm diameter void inside a copper interconnection.

Correction of absorption-edge artifacts in polychromatic X-ray tomography in a scanning electron microscope for 3D microelectronics.

X-ray tomography is widely used in materials science. However, X-ray scanners are often based on polychromatic radiation that creates artifacts such as dark streaks. We show this artifact is not always due to beam hardening. It may appear when scanning samples with high-Z elements inside a low-Z matrix because of the high-Z element absorption edge: X-rays whose energy is above this edge are strongly absorbed, violating the exponential decay assumption for reconstruction algorithms and generating dark streaks. A method is proposed to limit the absorption edge effect and is applied on a microelectronic case to suppress dark streaks between interconnections.

[Fast and accurate method for theophylline analysis in preterm babies using gas chromatography and nitrogen selective detector (NFID) (author's transl)]. / Méthode de chromatographie en phase gazeuse-NFID pour la détermination rapide de la théophylline sanguine chez les enfants prématures.

The combined utilization of (a) a weak polar OV-1 phase, (b) an on-column methylation using a methylating agent commercially available, (c) a nitrogen selective detector (NFID) and (d) a small volume of sample, allows the development of a fast (less than 20 min) and accurate method for theophylline analysis in preterm babies. With 50 microliter of capillary whole blood sample, its limit of sensitivity was 0.5 microgram/ml of theophylline. This method is most desirable for theophylline monitoring in treating apnea of premature infants.

[Prospective study of neonatal genital mycoplasma colonization and infection]. / Etude prospective de la colonisation et de l'infection néonatales à mycoplasmes génitaux.

Genital mycoplasmas have been implicated in different neonatal diseases as pneumonia, sepsis and meningitis. This prospective study was conducted to specify their role in these diseases. POPULATION AND METHODS--A pharyngeal or tracheal swab specimen for mycoplasmas culture was obtained from 100 infants admitted consecutively to the Neonatal Care Unit (NCU) during the first 24 hours of life. Mycoplasma culture of blood and cerebrospinal fluid was also performed. Pharyngeal and/or tracheal specimens were collected again on days 5, 15 and 28 if the child was still in the NCU. Mycoplasma hominis (Mh) and Ureaplasma urealyticum (Uu) were identified by culture in a modified Hayflick's medium. RESULTS--Three-hundred and ten pharyngeal or tracheal swabs were obtained (100 on day 0, 89 on day 5, 72 on day 15 and 49 on day 28). Twenty-one infants had one or more positive swabs in the first five days of life (20 on day 0 and one on day 5); those forming the "Myco+" group and the others forming the "Myco-" group. Uu was isolated alone from 20 infants, associated with Mh from one. Both groups were similar for gestational age, birth weight, maternal fever during labor, prolonged rupture of the fetal membranes or chorioamnionitis and for the incidence of acute respiratory distress. There was a statistically significant difference for the route of delivery (chi 2 < 0.02). One blood culture (from 92 performed) was positive for Uu and another positive for Uu and Mh. Both children were cured without any specific mycoplasmacidal therapy. Three children had probable Uu infection and were also cured without specific therapy. CONCLUSIONS--A pharyngeal colonization with genital mycoplasmas is common in the first days of life (21%) but our data do not allow us to conclude that they are accountable for newborn infections.

Deep sub micrometer imaging of defects in copper pillars by X-ray tomography in a SEM.

The potential of X-ray nanotomography hosted in a SEM in presented in this paper. In order to improve the detail detectability of this system, which is directly related to the X-ray source size, thin metal layers have been studied and installed in the equipment. A 3D resolution pattern has been created in order to determine the smallest detectable features by this setup. This sample is a 25 µm diameter copper pillar in which size-controlled holes have been milled using a plasma-focused ion beam. This pattern has then been scanned and the resulting 3D reconstruction demonstrates that the instrument is able to detect 500 nm diameter voids in a copper interconnection, as used in 3D integration.

Three-dimensional imaging of copper pillars using x-ray tomography within a scanning electron microscope: a simulation study based on synchrotron data.

While microelectronic devices are frequently characterized with surface-sensitive techniques having nanometer resolution, interconnections used in 3D integration require 3D imaging with high penetration depth and deep sub-micrometer spatial resolution. X-ray tomography is well adapted to this situation. In this context, the purpose of this study is to assess a versatile and turn-key tomographic system allowing for 3D x-ray nanotomography of copper pillars. The tomography tool uses the thin electron beam of a scanning electron microscope (SEM) to provoke x-ray emission from specific metallic targets. Then, radiographs are recorded while the sample rotates in a conventional cone beam tomography scheme that ends up with 3D reconstructions of the pillar. Starting from copper pillars data, collected at the European Synchrotron Radiation Facility, we build a 3D numerical model of a copper pillar, paying particular attention to intermetallics. This model is then used to simulate physical radiographs of the pillar using the geometry of the SEM-hosted x-ray tomography system. Eventually, data are reconstructed and it is shown that the system makes it possible the quantification of 3D intermetallics volume in copper pillars. The paper also includes a prospective discussion about resolution issues.

Antenatal sonographic features of aneurysmal dilatation of a vitelline vein.

We report a case of aneurysmal dilatation of a vitelline vein observed antenatally. Intra-abdominal vascular dilatation was diagnosed on ultrasound examination at 24 weeks' gestation. The relationship with the umbilicus and portal vein suggested the diagnosis of umbilical vein varix. Fetal tolerance remained excellent in spite of a gradual increase in the size of the dilated vein. Postnatal ultrasound examination revealed thrombosis of the aneurysm with gradual extension to the portal vein and the onset of serious coagulation problems. Operative findings on postnatal day 9 included the absence of intra-abdominal umbilical vein, and the presence of an abnormal, dilated and thrombosed vein connecting the umbilicus to the portal vein and following the trajectory of the right vitelline vein. Corrective surgery was attempted by resection of the aneurysm and portal thrombectomy, but this did not prevent the development of portal obstruction syndrome with cavernous hemangioma. This anomaly, in which the fetal venous return uses the vitelline vein in the absence of the umbilical vein, does not appear to have been described before. The mechanism in question could be anastomosis between the right vitelline vein and umbilical vein. Antenatal diagnosis should enable early surgical management before the formation of a portal thrombosis.

Clinical, biochemical, magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H MRS) findings in a fourth case of combined D- and L-2 hydroxyglutaric aciduria.

We report the fourth case of combined D-and L-2-hydroxyglutaric aciduria presenting with neonatal encephalopathy and subependymal cysts.

[Refractory hypoxemia in the newborn. Treatment with tolazoline]. / Hypoxémie réfractaire chez le nouveau-né. Traitement par la tolazoline.

Persiting pulmonary arterial hypertension, whether secondary to known lung disease or apparently idiopathic, may induce refractory hypoxaemia in the newborn. Tolazoline, pulmonary vasodilator of choice here, was used to treat this syndrome in 13 newborns. Therapeutic indications, precautions and possible side-effects are discussed.

Neonatal respiratory distress due to mumps.

We report an infant of 35 weeks' gestation who developed severe respiratory distress and pneumonitis due to perinatal mumps virus infection.

[Neonatal nemaline myopathy with favorable outcome]. / Myopathie à bâtonnets de découverte néonatale et d'évolution favorable.

A case of neonatal nemaline myopathy without respiratory distress is reported in a neonate. Its relatively benign course allowed survival without major complications. The discovery of a "central core disease" myopathy in her asymptomatic father confirms the relation between both entities.

[A prospective study of mycoplasma infection in a neonatal unit]. / Etude prospective de l'infestation à mycoplasmes dans une unité de néonatologie.

Ureaplasma urealyticum and Mycoplasma hominis were recovered from nasopharyngeal aspirates from 25% of 63 infants admitted to a neonatal unit; this proportion is significantly higher than that seen in a control population of maternity ward babies (0%). Birth by cesarean section was associated with a reduced risk of recovery of mycoplasmas. No specific diseases were significantly associated with recovery of mycoplasmas; furthermore, no obstetrical factors were associated with recovery of mycoplasmas from the neonates and no association was found between mycoplasma infection and respiratory distress. However, fetal distress, probably of multifactorial origin, was found in 44% of neonates with positive cultures for Ureaplasma urealyticum; this proportion was significantly elevated as compared with the subgroup of infants negative for U. urealyticum, suggesting that fetal distress may increase the infectivity of this opportunistic organism.

[Moebius syndrome with pharyngo-laryngeal paralysis in a premature infant]. / Syndrome de Moebius avec paralysie pharyngo-laryngée chez une prématurée. Difficultés du diagnostic et de la prise en charge néonatale.

A case of Moebius syndrome in a premature baby is reported. After a phase of neonatal severe respiratory distress syndrome, the baby presented with a persistent facial paralysis, already present at birth and inability to close the eyes (also present in her father), without ophthalmoplegia. An unusual pharyngeal and laryngeal paralysis was also present: it led to tracheal intubation then tracheostomy and gastrostomy. CT scan at 15 months of age showed hypoplasia of brain stem. The difficulties of managing bulbar paralysis in such a premature baby are emphasized.

Treatment of caffeine intoxication by exchange transfusion in a newborn.

The symptoms of acute poisoning after accidental administration of ten times the usually prescribed dosage of caffeine in a premature infant included the following neurological signs: incessant tremors, hypertonia, continuous opisthotonos posture, whining and crying and digestive disturbances. The very high serum caffeine levels, 160 mg/l, determined 66 hours after the first administration was confirmed by the very high cerebrospinal fluid caffeine concentration 115 mg/l. Two exchange transfusions performed at an interval of 16 hours produced a large decrease in serum caffeine levels of approximately 40 mg/l each time, and a similar decrease in the cerebrospinal fluid concentration. The clinical status of the infant improved very rapidly and the child's psychomotor development was normal at 3 months of age.

[Hemorrhagic colitis in newborn infants. Apropos of 32 cases]. / La colite hémorragique du nouveau-né. A propos de 32 cas.

The authors report 32 cases of neonatal hemorrhagic colitis observed during a 19-mth period in the neonatal unit of the University Medical Center of Caen. Neonatal hemorrhagic colitis is characterized by rectal bleeding alone occurring mostly in premature infants. There are no accompanying clinical, biological or radiological signs of necrotizing enterocolitis. The evolution is always benign without any particular therapy. Prematurity and cesarean section appear to be the most important etiological factors. The pathogenesis is probably multifactorial. The differential diagnosis with necrotizing enterocolitis is difficult in the beginning.

[Early myoclonic encephalopathy. Delimitation of the syndrome in view of genetic counseling]. / Encéphalopathie myoclonique précoce. Essai de délimitation du syndrome en vue d'un conseil génétique.

Early myoclonic encephalopathy is a rare neurologic disease of unknown etiology whose course is always quickly unfavorable. Clinical features include lack of mental development and myoclonic jerks which appear during the neonatal period. There are no biological abnormalities but EEG shows a pattern of suppression-burst. In the spectrum of neonatal epileptic encephalopathic syndromes, it is important to distinguish this syndrome from non-ketotic hyperglycinemia and Ohtahara' syndrome. Two new familial cases authors to emphasize on the difficulty of nosological delineation of these syndromes. However it is necessary to delimit this disease for a genetic purpose.