Elastic and thermo-elastic characterizations of thin resin films using colored picosecond acoustics and spectroscopic ellipsometry.

Colored Picosecond Acoustics (CPA) and Spectroscopic Ellipsometry (SE) are combined to measure elastic and thermoelastic properties of polymer thin-film resins deposited on 300 mm wafers. Film thickness and refractive index are measured using SE. Sound velocity and thickness are measured using CPA from the refractive index. Comparing the two thicknesses allows checking consistency between both approaches. The same combination is then applied at various temperatures from 19° to 180°C. As the sample is heated, both thickness and sound velocity change. By monitoring these contributions separately, the Temperature Coefficient on sound Velocity (TCV) and the Coefficient on Thermal Expansion are deduced. The protocol is applied to five industrial samples made of different thin-film resins currently used by microelectronic industry. Young's modulus varies from resin to resin by up to 20%. TCV is large on each resin and varies from one resin to another up to 57%.

Incidence, complications, and costs of peripheral venous catheter-related bacteraemia: a retrospective, single-centre study.

BACKGROUND: Peripheral venous catheter (PVC) complications occur on average in approximately half of patients, necessitating premature PVC removal, suspending administration of ongoing therapies, and catheter replacement. AIM: To estimate the current incidence, complications, and costs of bloodstream infection (BSI) attributable to PVCs. METHODS: Patients with PVC-related BSI (cases) were matched with patients without PVC-related BSI (controls). FINDINGS: From January 1st, 2018 to March 31st, 2020, a total of 9833 out of 113,068 patients visiting the emergency department (9%) were hospitalized in a medical ward after insertion of a PVC. Among them, 581 (6%) had at least one positive blood culture. Twenty-five (4%) of these were judged as having a PVC-related BSI. Major complications were noted in nine patients. One patient presented severe sepsis requiring admission to intensive care unit for eleven days followed by thoracic (T4-T7) spondylodiscitis requiring prolonged antimicrobial therapy. Another patient developed mitral valve endocarditis also requiring prolonged antimicrobial therapy. One patient developed a pre-sacral abscess three months after initial PVC infection and required hospital readmission for 19 days for drainage. Median (interquartile range) hospital stay costs were €11,597 (8,479-23,759) for cases and €6,789 (4,019-10,764) for controls, leading to median additional costs of €5,587. CONCLUSION: Though the risk of developing PVC-related BSI in patients admitted to medical wards may seem low, complications of PVC-related BSI are severe, and associated mortality remains high. The financial resources used to treat these complications could be better spent on prevention, including the use of high-quality materials and technologies, and improved training of healthcare providers.

Ultrafast optical technique for measuring the electrical dependence of the elasticity of piezoelectric thin film: demonstration on AlN.

We present a technique based on ultrafast acoustics which permits us to measure the electrical dependence of the elastic properties of a thin piezoelectric layer. Ultrafast acoustics offers a unique way of measuring elastic properties of thin-layer in a non-destructive way using ultrashort optical pulses. We apply this technique to a thin layer to which a dc voltage is simultaneously applied. Both the film thickness and the sound velocity are affected. The two effects can be separated by use of a semi-transparent top electrode. A demonstration is made on a thin aluminum nitride (AlN). From that the d(33) piezoelectric coefficient and the stiffness variation induced by the bias in AlN are measured.

Posterior reversible encephalopathy syndrome in childhood cancer.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is characterized by seizures, headaches, altered mental status, cortical blindness and typical transient lesions on magnetic resonance imaging. PATIENTS AND METHODS: We describe seven childhood cancer patients with clinical and radiological symptoms of PRES, and reviewed all well-documented PRES cases reported during childhood cancer treatment. RESULTS: Fifty-six children with PRES, including our 7 cases, were identified in the literature. Mean age at onset was 9 (range: 2-17) years. Primary diagnoses were acute lymphoblastic leukemia (n = 31), acute myeloid leukemia (n = 5), non-Hodgkin lymphoma (n = 7) and solid tumors (n = 13). PRES patients presented with seizures (n = 50), altered mental status (n = 20), visual disturbances (n = 24) and/or headaches (n = 17). PRES was associated with hypertension in 49 patients. About 86% of the patients had both clinical and radiological reversible symptoms. Four patients developed epilepsy, in one patient ataxia remained and one patient had a persistent mydriasis. CONCLUSION: Although PRES has predominantly been described in leukemia patients, it occurs in children with solid tumors as well. Hypertension seems to be the most important trigger for the occurrence of PRES during childhood cancer treatment. Seizures are the most common accompanying sign. Symptoms and radiological findings normalize in ∼90% of the cases, but in 10% neurological symptoms remain.

Ultrafast acoustics in the middle UV range: coherent phonons at higher frequencies and in smaller objects.

We show that the propagation of coherent acoustic phonons generated by femtosecond optical excitation can be clearly resolved using a probe laser in the middle UV (MUV) range. The MUV probe is easily produced from a high-repetition-rate femtosecond laser and a homemade frequency tripler. We present various experimental results that demonstrate efficient and high frequency detection of acoustic phonons. Thus, we show that the MUV range offers a unique way to reach higher frequencies and probe smaller objects in ultrafast acoustics.

Strong generation of coherent acoustic phonons in semiconductor quantum dots.

We present experimental results obtained in two-color pump-probe experiments performed in semiconductor self-assembled quantum dot (QD) layers. The sample reflectivities present several acoustic contributions, among which are strong acoustic phonon wave packets. A comparison between one- and two-color experiments and a fine analysis of the echo shape attest that a high magnitude phonon pulse emerges from each single QD layer. This conclusion is supported by a numerical modeling which perfectly reproduces our experimental signals only if we introduce a strong generation in each QD layer. We explain such a strong emission thanks to an efficient capture of the carriers by the QDs.

Individual and collective vibrational modes of nanostructures studied by picosecond ultrasonics.

We report on picosecond ultrasonic measurements obtained on aluminum and platinum nanostructures with variable dot size and lateral periodicity which realized a 2D phononic crystal. Performing investigations at different resolution scales, we have identified individual modes of vibration depending on the dot size, and mode of vibration strongly correlated with the bi-dimensional organization. The platinum dots sputtered on an aluminum layer have shown a behavior of isolated oscillators without any coupling between neighbor elements in this phononic crystal. The frequency of such normal modes, extracted from time resolved measurements are in good agreement with 3D finite element simulations. In contrast, with aluminum dot systems where the coupling is more efficient we observe a complex spectrum of vibrational modes related to the band structure induced by the bi-dimensional patterning.

Model order selection for quantification of a multi-exponential magnetic resonance spectrum.

Magnetic resonance spectroscopic signals analyzed by time-domain models in order to retrieve estimates of the model parameters usually require prior knowledge about the model order. For multi-exponential signals where a superposition of peaks occurs at the same resonance frequency, but with different damping values, model order selection criteria from information theory can be used. In this study, several generalized versions of information criteria are compared using Monte-Carlo simulation signals. The best criterion is further applied for selecting the model order of experimental glycogen signals.

The use of multivariate MR imaging intensities versus metabolic data from MR spectroscopic imaging for brain tumour classification.

This study investigated the value of information from both magnetic resonance imaging and magnetic resonance spectroscopic imaging (MRSI) to automated discrimination of brain tumours. The influence of imaging intensities and metabolic data was tested by comparing the use of MR spectra from MRSI, MR imaging intensities, peak integration values obtained from the MR spectra and a combination of the latter two. Three classification techniques were objectively compared: linear discriminant analysis, least squares support vector machines (LS-SVM) with a linear kernel as linear techniques and LS-SVM with radial basis function kernel as a nonlinear technique. Classifiers were evaluated over 100 stratified random splittings of the dataset into training and test sets. The area under the receiver operating characteristic (ROC) curve (AUC) was used as a global performance measure on test data. In general, all techniques obtained a high performance when using peak integration values with or without MR imaging intensities. For example for low- versus high-grade tumours, low- versus high-grade gliomas and gliomas versus meningiomas, the mean test AUC was higher than 0.91, 0.94, and 0.99, respectively, when both MR imaging intensities and peak integration values were used. The use of metabolic data from MRSI significantly improved automated classification of brain tumour types compared to the use of MR imaging intensities solely.

Classification of brain tumours using short echo time 1H MR spectra.

The purpose was to objectively compare the application of several techniques and the use of several input features for brain tumour classification using Magnetic Resonance Spectroscopy (MRS). Short echo time 1H MRS signals from patients with glioblastomas (n = 87), meningiomas (n = 57), metastases (n = 39), and astrocytomas grade II (n = 22) were provided by six centres in the European Union funded INTERPRET project. Linear discriminant analysis, least squares support vector machines (LS-SVM) with a linear kernel and LS-SVM with radial basis function kernel were applied and evaluated over 100 stratified random splittings of the dataset into training and test sets. The area under the receiver operating characteristic curve (AUC) was used to measure the performance of binary classifiers, while the percentage of correct classifications was used to evaluate the multiclass classifiers. The influence of several factors on the classification performance has been tested: L2- vs. water normalization, magnitude vs. real spectra and baseline correction. The effect of input feature reduction was also investigated by using only the selected frequency regions containing the most discriminatory information, and peak integrated values. Using L2-normalized complete spectra the automated binary classifiers reached a mean test AUC of more than 0.95, except for glioblastomas vs. metastases. Similar results were obtained for all classification techniques and input features except for water normalized spectra, where classification performance was lower. This indicates that data acquisition and processing can be simplified for classification purposes, excluding the need for separate water signal acquisition, baseline correction or phasing.

Brain tumor classification based on long echo proton MRS signals.

There has been a growing research interest in brain tumor classification based on proton magnetic resonance spectroscopy (1H MRS) signals. Four research centers within the EU funded INTERPRET project have acquired a significant number of long echo 1H MRS signals for brain tumor classification. In this paper, we present an objective comparison of several classification techniques applied to the discrimination of four types of brain tumors: meningiomas, glioblastomas, astrocytomas grade II and metastases. Linear and non-linear classifiers are compared: linear discriminant analysis (LDA), support vector machines (SVM) and least squares SVM (LS-SVM) with a linear kernel as linear techniques and LS-SVM with a radial basis function (RBF) kernel as a non-linear technique. Kernel-based methods can perform well in processing high dimensional data. This motivates the inclusion of SVM and LS-SVM in this study. The analysis includes optimal input variable selection, (hyper-) parameter estimation, followed by performance evaluation. The classification performance is evaluated over 200 stratified random samplings of the dataset into training and test sets. Receiver operating characteristic (ROC) curve analysis measures the performance of binary classification, while for multiclass classification, we consider the accuracy as performance measure. Based on the complete magnitude spectra, automated binary classifiers are able to reach an area under the ROC curve (AUC) of more than 0.9 except for the hard case glioblastomas versus metastases. Although, based on the available long echo 1H MRS data, we did not find any statistically significant difference between the performances of LDA and the kernel-based methods, the latter have the strength that no dimensionality reduction is required to obtain such a high performance.

Does the combination of magnetic resonance imaging and spectroscopic imaging improve the classification of brain tumours?

Magnetic Resonance Imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) play an important role in the noninvasive diagnosis of brain tumours. We investigate the use of both MRI and MRSI, separately and in combination with each other for classification of brain tissue types. Many clinically relevant classification problems are considered; for example healthy versus tumour tissues, low- versus high-grade tumours. Linear as well as nonlinear techniques are compared. The classification performance is evaluated by the area under the receiver operating characteristic (ROC) curve (AUC). In general, all techniques achieve a high performance, except when using MRI alone. For example, for low- versus high-grade tumours, low- versus high-grade gliomas, gliomas versus meningiomas, respectively a test AUC higher than 0.91, 0.93 and 0.98 is reached, when both MRI and MRSI data are used.

Evaluation of a commercial line probe assay for identification of mycobacterium species from liquid and solid culture.

The performance of a commercial line probe assay (LiPA) (Inno-LiPA Mycobacteria; Innogenetics, Belgium) for the detection and identification of Mycobacterium species from liquid and solid culture was evaluated at five routine clinical laboratories. The LiPA method is based on the reverse hybridization principle, in which the mycobacterial 16S-23S ribosomal RNA (rRNA) spacer region is amplified by polymerase chain reaction (PCR). Amplicons are subsequently hybridized with oligonucleotide probes arranged on a membrane strip and detected by a colorimetric system. The test detects the presence of Mycobacterium species and specifically identifies Mycobacterium tuberculosis complex, Mycobacterium kansasii, Mycobacterium xenopi, Mycobacterium gordonae, Mycobacterium avium complex, Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium scrofulaceum, and Mycobacterium chelonae - Mycobacterium abscessus complex. The results of LiPA were compared with the results obtained using traditional biochemical and molecular tests (DNA probe-based techniques, PCR restriction enzyme analysis of the 65 kDa heat-shock protein gene, and sequencing of the 16S rDNA). A total of 669 isolates, 642 of which were identified as Mycobacterium species and 27 as non- Mycobacterium species, were tested by LiPA. After analysis of 14 initially discordant results and exclusion of one isolate, concordant results were obtained for 636 of 641 Mycobacterium isolates (99.2% accuracy). All Mycobacterium species reacted with the MYC ( Mycobacterium species) probe (100% sensitivity), and all non- Mycobacterium species were identified as such (100% specificity).

[Qualitative assessment of labile blood product prescription in Le Havre Hospital]. / Evaluation qualitative de la prescription de produits sanguins labiles au groupe hospitalier du Havre.

This retrospective study assessed the conformity of prescriptions of labile blood products as well as the respect of legal requirements and recommendations concerning red blood cells specifications. This study was carried out in two phases one year apart, so as to be able to compare between them. It consisted in an analysis of the administrative and medical information present on the prescription forms and of the discrepancies between the prescribed product and that which was dispensed. Quality of prescriptions was overall better, but some points needed further improvement. The data moreover showed that some prescriptions of phenotyped and cross-matched red blood cells were incomplete. This did not improve over time. Out of 1000 prescriptions for red blood cells, 216 were altered by the transfusion service dispensing unit. A closer look at these changes showed that 49% were justified by statutory requirements or by local protocols. The discrepancies observed between the prescribed product and that which was dispensed were partly due to a poor understanding by the prescribers of statutory requirements. However they are mostly related to particular circumstances, such as emergencies. Furthermore, the prescribers expected the transfusion center to adapt the product in terms of the clinical context.

Evidence of laser-wavelength effect in picosecond ultrasonics: possible connection with interband transitions.

We have studied the effect of wavelength change on picosecond acoustic pulses generated using a femtosecond laser. For the first time, we show that the pulse shape can be strongly influenced by the laser wavelength. The results are in excellent agreement with a calculation based on a thermoelastic model which connects them to significant changes in the piezo-optical constants. There are similarities between the present study and stress modulation spectroscopy, which allows us to ascribe the observations to interband transitions and suggests thus a new potentiality of picosecond ultrasonics.

ESHRE guidelines for good practice in IVF laboratories. Committee of the Special Interest Group on Embryology of the European Society of Human Reproduction and Embryology.

Education has always been a priority for the European Society of Human Reproduction and Embryology (ESHRE). Many efforts have been dedicated to promoting knowledge of techniques, procedures and strategies in order to ensure use of the highest quality practices in reproductive medicine. The need to develop a set of guidelines was a logical consequence that found its first expression in 1990, when Focus on Reproduction (vol. 1, pp. 10-38) published the first guidelines which were distributed among the membership. Five years later a new, more complete edition with several novel techniques and developments appeared in Human Reproduction (vol. 10, pp. 1246-1271). Both have proved to be invaluable references. Five more years have now passed. The necessity to produce current guidelines for good IVF laboratory practice has provided the strongest motivation. This originated from the increasing awareness that embryologists have a duty to prevent unintentional incidents that might result from poor practice in the laboratory. Therefore, the Embryology Special Interest Group (SIG) undertook to draw up guidelines aimed at giving support and guidance to the laboratory staff. All the aspects required to provide a safe working system were taken into consideration by members of the SIG and their effort produced this document. We hope that it will assist staff in achieving the best clinical outcome for their patients.

Leptomeningeal metastases from ethmoid sinus adenocarcinoma: clinico-radiological correlation.

A patient with sinonasal adenocarcinoma is presented with leptomeningeal metastases affecting multiple cranial nerves and spinal nerve roots. Head and neck cancer is known to be an extremely rare source for leptomeningeal metastatic spread. The cranial nerves, the spinal cord and roots and the cerebral hemispheres can be affected in case of leptomeningeal metastatic spread. Examination of the CSF is the hallmark of the diagnosis if leptomeningeal metastatic spread is suspected, but this case illustrates that the combination of specific clinical features on one hand and specific lesions on the Gd-enhanced T1-weighted MRI study on the other hand is reliable enough to make a presumed diagnosis if the CSF analysis remains negative. We suggest that in our patient direct leptomeningeal spread occurred through the cribriform plate to the CSF, followed by further spread in a gravity dependent way.