Iterative method for optical modelling of perovskite-based tandem solar cells.

We present an iterative method to model the optical properties of a complete semitransparent perovskite solar cell. It is based on spectroscopic characterizations and accounts for porosity and incoherence effects. We provide the complex refractive indices of each layer, and we identify the main sources of optical losses. The optical model is also coupled to an electrical model of 4T perovskite/silicon tandem solar cells. It allows to evaluate the interplay between the optical and electrical losses, and the balance between the efficiency of the top and bottom cells. These models provide an effective way to design future tandem devices.

Psoas proximal insertion as a simple and reliable landmark for numbering lumbar vertebrae on MRI of the lumbar spine.

OBJECTIVE: To evaluate the value of psoas muscle proximal insertion for correct numbering of the lumbar vertebrae in MRI, in particular in case of lumbosacral transitional vertebra (LSTV). METHODS: Two radiologists assessed 477 MRI scans of the lumbar spine with a sagittal localizer sequence on the whole spine for numbering vertebrae caudally from C2. Proximal insertion of the psoas was determined as the most proximal vertebra with psoas over half of its body on coronal T2 STIR sequence. The last lumbar vertebra was named considering both its number and the presence or absence of LSTV according to Castellvi classification. These same parameters were also assessed on 207 PET-CT scans of another cohort including the whole spine. RESULTS: Proximal insertion of the psoas was L1 in 94.1% of cases: 98.5% in case of modal anatomy, 81.4% in case of LSTV, and 51.7% in case of missing or supernumerary lumbar vertebra without LSTV. There was no statistically significant difference between MRI and CT data. The inter-reader agreement for determination of psoas proximal insertion was excellent (kappa = 0.96). CONCLUSION: Proximal insertion of the psoas muscle is a helpful marker for correct numbering of the lumbar vertebrae in MRI and to detect a complete lumbosacral segmentation anomaly. KEY POINTS: • Proximal insertion of the psoas muscle can be easily identified on a coronal T2 STIR sequence. • Psoas proximal insertion on the spine almost always designates the first lumbar vertebra and is helpful to accurately number all lumbar vertebrae, especially in case of lumbosacral transitional vertebra. • Conversely, when psoas muscle does not insert five lumbar bodies above the apparent lumbosacral joint, the probability of variation in the number of lumbar vertebrae is high.

Correction to: In vitro prediction of stop-codon suppression by intravenous gentamicin in patients with cystic fibrosis: a pilot study.

The original article [1] contains errors in Table 1 affecting some of the presented oligonucleotide sequences and readthrough values in Table 1.

Ultrasonographic evaluation of gastric content during labour under epidural analgesia: a prospective cohort study.

BACKGROUND: Women in labour are considered at risk of gastric content aspiration partly because the stomach remains full before delivery. Ultrasonographic measurement of antral cross-sectional area (CSA) is a validated method of gastric content assessment. Our aim was to determine gastric content volume and its changes in parturients during labour under epidural analgesia using bedside ultrasonography. METHODS: The cut-off value corresponding to an increased gastric content was determined by ultrasound measurement of antral CSA in six pregnant women in late pregnancy before and after ingestion of 250 ml of non-clear liquid. Antral CSA was then measured twice in 60 parturients who presented in spontaneous labour: when the anaesthesiologist was called for epidural analgesia catheter placement, and at full cervical dilatation. Patient-controlled epidural analgesia was performed with a solution of ropivacaine and sufentanil. RESULTS: After liquid ingestion, antral CSA (mm(2)) increased from 90 (range, 80-151) to 409 (range, 317-463). A CSA of 320 was taken as cut-off value. The feasibility rate of antral CSA determination was 96%. CSA decreased from 319 [Q1 158-Q3 469] to 203 [Q1 123-Q3 261] during labour (P=2×10(-7)). CSA was >320 in 50% of parturients at the beginning of labour vs 13% at full cervical dilatation (P=0.006). CONCLUSIONS: Bedside ultrasonographic antral CSA measurement is feasible in pregnant women during labour and easy to perform. The observed decrease in antral CSA during labour suggests that gastric motility is preserved under epidural anaesthesia. The procedure could be used to assess individual risk of gastric content aspiration during labour.

Clinical-radiological correlation after functional endoscopic sinus surgery in patients with chronic rhinosinusitis: interest of a sinonasal aerial volumetry.

BACKGROUND: Although a CT scan is often performed after functional endoscopic sinonasal surgery (FESS) in patients with chronic rhinosinusitis, its role hasn`t been firmly established. The goal of this study is to investigate the correlation between symptoms and CT findings before and after FESS for chronic rhinosinusitis. In addition, the interobserver agreement for both sinonasal aerial volumetry and CT score is assessed. METHODS: Thirty-three patients surgically treated for chronic rhinosinusitis were included in this prospective study. Conventional and modified Lund-Mackay scores and sinonasal volumetry were determined by two radiologists before (M0), at 3 months (M3) and 1 year (M12) after surgery. The symptoms were evaluated by the 22-item SinoNasal Outcome Test (SNOT-22). RESULTS: Change of SNOT-22 and air volume were significantly correlated between M0 and M12, but not between M0 and M3, for both readers. Compared to other scores, volume had the best intraclass correlation coefficient and reproducibility, according to the Bland-Altman analysis. No correlation was found between SNOT-22 and CT scores before and after surgery, except between M12 and M0 for one reader. CONCLUSION: The correlation between CT scan and symptoms is low or absent. The measurement of sinonasal air volume is best correlated with the symptoms after surgery, with the best inter-observer agreement.

Electrodeposition of ZnO nanorod arrays on ZnO substrate with tunable orientation and optical properties.

The electrodeposition of ZnO nanorods on ZnO:Al films with different orientations is reported. The influence of the total charge exchanged during electrodeposition on the nanorod's geometry (length, diameter, aspect ratio and surface density) and the optical transmission properties of the nanorod arrays is studied on a [0001]-oriented ZnO:Al substrate. The nanorods are highly vertically oriented along the c axis, following the lattice matching with the substrate. The growth on a [1010] and [1120] ZnO:Al-oriented substrate with c axis parallel to the substrate leads to a systematic deviation angle of 55 degrees from the perpendicular direction. This finding has been explained by the occurrence of a minority orientation with the [1011] planes parallel to the surface, with a preferential growth on corresponding [0001] termination. Substrate crystalline orientation is thereby found to be a major parameter in finely tuning the orientation of the nanorod array. This new approach allows us to optimize the light scattering properties of the films.

[Retrospective study conducted in northern Finistère about the role of breast MRI in normal breast screening, experience in 51 patients]. / Etude rétrospective dans le Nord-Finistère sur la place de l'IRM mammaire devant un bilan sénologique normal, à propos de 51 cas.

OBJECTIVES: To study the role and indications of breast MRI in normal breast screening. PATIENTS AND METHODS: Retrospective study of 51 patients (mean age of 51 years) conducted in northern Finistère. Each patient had a normal (BI-RADS 1 or 2) breast screening (mammography and echography). Four indications for MRI were chosen: screening of high-risk patients, high-density breasts, radio-clinical discordance, and breasts prostheses. Breast MRI were reviewed according to BI-RADS classification. Abnormalities categorized in BI-RADS 4 or 5 were confirmed histologically. RESULTS: Thirteen patients underwent histological analysis. Nine invasive carcinomas were identified (six invasive lobular carcinomas (ILC), two mixed carcinomas, one invasive ductal carcinoma). For these patients, the reason for performing MRI was a radio-clinical discordance. DISCUSSION AND CONCLUSION: The study demonstrates the breast MRI value for radio-clinical discordance and the key role of MRI in diagnostic challenge of ILC. In literature review, MRI has a role even if breast screening is normal: radio-clinical discordance, screening of patients with high-risk, breasts prostheses in certain cases. Breast density comes as an additional criteria to perform this exam.

[How translation termination factor eRF1 Euplotes does not recognise UGA stop codon].

In universal-code eukaryotes, a single class-1 translation termination factor eRF1 decodes all three stop codons, UAA, UAG, and UGA. In some ciliates with variant genetic codes one or two stop codons are used to encode amino acid(s) and are not recognized by eRF1. In Stylonychia, UAG and UAA codons are reassigned as glutamine codons, and in Euplotes, UGA is reassigned as cysteine codon. In omnipotent eRF1s, stop codon recognition is associated with the N-terminal domain of eRF1. Because variant-code ciliates most likely evolved from universal code ancestor(s), structural features should exist in ciliate eRF1s that restrict their stop codon recognition. To find out amino acid residues which confer UAR-only specificity to Euplotes aediculatus eRF1, eRFI chimeras were constructed by swapping eRF1 E. aediculatus N-terminal domain sequences with the matching ones from the human protein. In these chimeras the MC-domain was from human eRF1. Functional analysis of these chimeric eRFI highlighted the crucial role of the two regions (positions 38-50 and 123-145) in the N-terminal domain of E. aediculatus eRF1 that restrict E. aediculatus eRF1 specificity toward UAR codons. Possibly, restriction of eRF1 specificity to UAR codons might have been an early event occurring in independent instances in ciliate evolutionary history, possibly facilitating the reassignment of UGA to sense codons.

Contribution of brain CT in the diagnosis of tuberculous meningitis: a case report from Djibouti.

Tuberculous meningitis, a serious disease with high mortality and morbidity, remains frequent in countries with endemic tuberculosis. Its non-specific presentation often delays the introduction of appropriate treatment. Its definitive diagnosis requires isolation of Mycobacterium tuberculosis from cerebrospinal fluid, although this test may be negative without conclusively ruling out this diagnosis. A presumptive diagnosis should be reached as soon as possible through a body of clinical evidence, including the lumbar puncture findings. Brain computed tomography (CT) with and without contrast medium injection is helpful for the diagnosis of tuberculous meningitis and its complications. We discuss the features of CT and their value in relation to a case of tuberculous meningitis in Djibouti, as well as the role of CT in managing this disease.

Inhibition of in vitro and ex vivo translation by a transplatin-modified oligo(2'-O-methylribonucleotide) directed against the HIV-1 gag-pol frameshift signal.

A 2'-O-methylribooligonucleotide containing a G1.U.G3 triad modified by trans-diamminedichloro-platinum(II) was targeted to the RNA region responsible for the gag-pol frameshifting during translation of the HIV-1 mRNA. The binding of the platinated oligonucleotide to its target RNA induced a rearrangement of the (G1, G3)-intrastrand crosslink, leading to the formation of an intermolecular oligonucleotide-RNA G-A crosslink. This resulted in the selective arrest of translation of a luciferase gene placed downstream of the HIV-1 frameshift signal both in a cell-free extract (rabbit reticulocyte lysate) and in RNA-transfected cells. A specific inhibition of luciferase activity was still observed when the oligonucleotide-RNA complex was not pre-formed prior to either translation or transfection. Moreover, a selective inhibition was also observed when the oligonucleotide and the plasmid DNA encoding the luciferase and bearing the RNA gag- pol frameshifting signal were co-transfected in NIH 3T3 cultured cells. Therefore the intra-strand-->interstrand conversion of the platinum crosslink kinetically competes with the translation machinery and blocks the polypeptide elongation. These transplatin-modified oligonucleotides which operate within a live cell on a 'real-time' basis and do not need an external triggering signal constitute a promising new class of selective reactive probes.

Tumor x host cell hybrids in the mouse: chromosomes from the normal cell parent maintained in malignant hybrid tumors.

We investigated whether the malignancy of hybrids between normal and malignant cells could be correlated with the loss of specific genes borne by specific chromosomes from the normal parent cells. Tumors produced in mice by the inoculation of Cl.1D cells (an L cell derivative) contained tumor x host cell hybrids. Hybrid cell populations isolated from 14 tumors were injected into 123 mice, of which 108 (87%) developed tumors. Metaphases of growing hybrid cell tumors were analyzed by use of a trypsin-Giemsa banding technique. The chromosomes contributed by the host (normal) parent cell could be distinguished from Cl.1D chromosomes, since the latter exhibited morphologic differences due to rearrangements. In the 14 hybrid tumors analyzed, we found that any one of the chromosomes of the host cell might be present, which indicated that none of the chromosomes from the normal cell bore genetic information capable of suppressing the malignancy of Cl.1D cells. Absence of complimentation in the hybrids suggested that, even if the accumulation of several mutations were necessary for malignant tumor growth of Cl.D1 cells, none of these mutations is recessive.

[Severe hyperhomocysteinemia revealing homocystinuria in two young adults with mild phenotype]. / Hyperhomocystéinémie sévère révélant une homocystinurie chez deux jeunes adultes présentant un phénotype peu marqué

INTRODUCTION: To the request of total plasma homocysteine determination in the investigation of vascular disease, diagnosis of homocystinuria in young adult patients with mild phenotype is not so rare. EXEGESIS: A 26-year-old man developed embolic cerebral infarction and a 22-year-old woman presented a right renal venous thrombosis one week after delivery. In each case, high concentration of total plasma homocysteine was first found and plasma and urinary amino acids analysis later on directed the diagnosis towards homocystinuria. Finally, reduced skin fibroblast cystathionine beta-synthase activity confirmed the diagnosis of homocystinuria. CONCLUSION: Total plasma homocysteine determination must be determined for screening for hyperhomocysteinemia in young adults with venous thromboembolism without characteristic phenotypic features of homocystinuria.

Presence and cell growth-related variations of glycogen in human colorectal adenocarcinoma cell lines in culture.

The presence and kinetics of intracellular glycogen levels were studied, in relationship to cell growth, in asynchronous and in synchronized cultures of four human colorectal adenocarcinoma cell lines (HT-29, HRT-18, SW-480, and Caco-2). The results show that a specific pattern of glycogen accumulation occurs during the process of cell growth of the studied cell lines. The kinetics of glycogen accumulation in asynchronous cultures were similar from one cell line to another and were characterized by a low amount in the exponential phase of growth, followed by a 3- to 4-fold increase in the stationary phase. The quantities found in either phase were specific for each cell line. The maximum values found in Caco-2, HRT-18, HT-29, and SW-480 cells were, respectively, 258.5 +/- 6.9 (S.D.), 88.9 +/- 2.6, 87.5 +/- 3, and 17.5 +/- 1.8 microgram of glycogen per mg of proteins. The kinetics of glycogen accumulation during the cell cycle was also studied in synchronized cultures of HT-29 and HRT-18 cell lines. Both cell lines exhibited a common pattern of low glycogen quantities during S, G2, and M followed by an increase beginning with G1 and peaking (2.5 to 3 times the initial values) in the middle of this phase. This was followed by a symmetrical decrease in the second half of G1.

Comparison of magneto-optical properties of various excitonic complexes in CdTe and CdSe self-assembled quantum dots.

We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly charged excitons (X(+), X(-)) allowed us to determine average parameters describing CdTe QDs (CdSe QDs): X-XX transition energy difference 12 meV (24 meV); fine-structure splitting δ1=0.14 meV (δ1=0.47 meV); g-factor g = 2.12 (g = 1.71); diamagnetic shift γ=2.5 µeV T(-2) (γ =1.3 µeV T(-2)). We find also statistically significant correlations between various parameters describing internal structure of excitonic complexes.

malM, a new gene of the maltose regulon in Escherichia coli K12. II. Mutations affecting the signal peptide of the MalM protein.

malM is the last gene of the malK-lamB-malM operon of Escherichia coli K12. It encodes a periplasmic protein. Mutations affecting the hydrophobic core of the N-terminal extension of the MalM protein have been isolated. They result in an increase in amount and specific activity of a MalM-LacZ hybrid protein. This result confirms that the signal peptide of the MalM protein is functional.

malM, a new gene of the maltose regulon in Escherichia coli K12. I. malM is the last gene of the malK-lamB operon and encodes a periplasmic protein.

The structure and expression of the distal part of the malK-lamB operon in Escherichia coli was studied. DNA sequencing was performed as far as a HinfI restriction site located 1313 base-pairs downstream from gene lamB. The open reading frame, formerly called molA, which begins 245 base-pairs downstream from gene lamB, is longer than was initially thought, and was renamed malM. It could encode a protein of 306 amino acid residues. The complete malM open reading frame was cloned under control of the tac 12 promoter. In maxicells, the resulting plasmid permitted tac12-promoted synthesis of two polypeptides, encoded by gene malM, with apparent molecular weights of 37 X 10(3) and 34.5 X 10(3). We provide strong evidence that the 34.5 X 10(3) Mr protein is derived from the 37 X 10(3) Mr protein by processing at the amino-terminal end, and that this processed form is located in the periplasmic space. We show that the chromosomal malM gene is expressed as part of the malK-lamB operon, and that its product is periplasmic. Finally, we demonstrate with nuclease S1 mapping experiments that the mRNA terminates at a typical rho-independent terminator located about 45 base-pairs beyond the end of gene malM, which is thus the last gene of the malK-lamB operon.

[Diverticula of the appendix and their complications: value of sonography (review of 21 cases)]. / Les diverticules appendiculaires et leurs complications: apport de l'échographie (à propos de 21 cas).

PURPOSE: Diverticulosis is defined by the presence of diverticula along any segment of the GI tract. Diverticulosis and its associated complications may involve the appendix. The imaging and histological findings of 21 cases of diverticulitis of the appendix are reviewed. MATERIALS AND METHODS: Sonography, because of its high spatial resolution, is an ideal imaging technique to diagnose diverticulitis of the appendix. RESULTS: Similar to diverticulosis of the large bowel, diverticula of the appendix correspond to pseudo-diverticula composed of mucosa and sub mucosa herniating through the muscular layer. Chronic inflammatory changes affect the surrounding appendicular wall, as confirmed by histological examination. Clinical symptoms range from chronic right lower quadrant abdominal pain to acute appendicitis and even peritonitis. CONCLUSION: Based on this retrospective analysis of 21 cases, it is possible to describe the specific and sensitive imaging findings for diagnosis of simple and complicated forms of diverticulitis of the appendix. Surgery is the treatment of choice because of the high risk of perforation.

UAG readthrough in mammalian cells: effect of upstream and downstream stop codon contexts reveal different signals.

BACKGROUND: Translation termination is mediated through an interaction between the release factors eRF1 and eRF3 and the stop codon within its nucleotide context. Although it is well known that the nucleotide contexts both upstream and downstream of the stop codon, can modulate readthrough, little is known about the mechanisms involved. RESULTS: We have performed an in vivo analysis of translational readthrough in mouse cells in culture using a reporter system that allows the measurement of readthrough levels as low as 10(-4). We first quantified readthrough frequencies obtained with constructs carrying different codons (two Gln, two His and four Gly) immediately upstream of the stop codon. There was no effect of amino acid identity or codon frequency. However, an adenine in the -1 position was always associated with the highest readthrough levels while an uracil was always associated with the lowest readthrough levels. This could be due to an effect mediated either by the nucleotide itself or by the P-site tRNA. We then examined the importance of the downstream context using eight other constructs. No direct correlation between the +6 nucleotide and readthrough efficiency was observed. CONCLUSIONS: We conclude that, in mouse cells, the upstream and downstream stop codon contexts affect readthrough via different mechanisms, suggesting that complex interactions take place between the mRNA and the various components of the translation termination machinery. Comparison of our results with those previously obtained in plant cells and in yeast, strongly suggests that the mechanisms involved in stop codon recognition are conserved among eukaryotes.