Effective pre-processing of long term noisy audio recordings: An aid to clinical monitoring

Nowadays, great attention is devoted to minimizing the discomfort caused by connection of patients to sensors for long-term monitoring of physiological parameters. Hence, the need for contact-less monitoring systems is increasingly recognized in clinical investigation. To this aim, audio signals recorded by ambient microphones are an appealing and increasing field of research: in the biomedical field, application of contact-less audio recording of long duration may concern obstructive apnoea syndrome, preterm newborns in Intensive Care Units, daily monitoring in occupational dysphonia, speech therapy, Parkinson and Alzheimer disease, monitoring of psychiatric and autistic subjects, etc. However, a significant amount of ambient noise is inevitably included in the records.Especially in the case of recordings that take a long time, manual extraction of clinically useful information from a whole record is a time-consuming operator-dependent task, the length of a whole recording (even several hours) being prohibitive both for perceptual analysis made by listening to it and for visual inspection of signal patterns. Moreover, objective measures of signal characteristics may serve clinicians as a common ground for diagnosis. Hence, automatic methods are needed to speed up and objectify the analysis task.The present work describes a new, automatic, fast and reliable method for extracting “voiced candidates” from audio recordings of long duration for both clinical and home applications.To demonstrate its effectiveness, the method is compared to existing software tools commonly used in biomedical applications using synthetic signals.     

Collagen ultrastructural symmetry and its malignant alterations in human breast cancer revealed by polarization‐resolved second‐harmonic generation microscopy

Several specific alterations of the extracellular matrix can be considered a distinctive hallmark of cancer. In particular, a different morphology of the collagen scaffold is frequently found within the peritumoural environment. In this study, we report about a significant difference in the ultrastructural organization of collagen at the supra‐molecular level between the perilesional scaffold and the tumour area in human breast carcinoma samples. In particular, we demonstrated that polarization‐resolved second‐harmonic generation (P‐SHG) microscopy is able to link the altered collagen architecture at the ultrastructural level found in perilesional tissue with a different organization of collagen fibrils at the molecular level.     

Ultrastructure variation in the spermatozoa of Pseudopaludicola frogs (Amphibia,Anura, Leptodactylidae), with brief comments on its phylogenetic relevance

The taxonomic history of the small frogs of the genus Pseudopaludicola from South America has been controversial. Phylogenetic inferences based on molecular data have identified four Pseudopaludicola clades, correlating with the known variation in karyotypes (2n = 22, 20, 18, and 16). In this study, the ultrastructure of the spermatozoa was analyzed in 12 species of the Pseudopaludicola, with the aim of describing their morphology and identifying characters that may contribute to a better understanding of the phylogenetic relationships. The spermatozoa presented marked differences in tail structures. The tails of the spermatozoa of the species with 2n = 22 chromosomes (Pseudopaludicola sp. 1 [P. pusilla group], Pseudopaludicola falcipes, P. mineira, and Pseudopaludicola saltica), as well as Pseudopaludicola ameghini and Pseudopaludicola ternetzi (2n=20), have juxta‐axonemal fibers, undulating membranes and axial fibers. In contrast, in the species with 2n = 18 (P. facureae, P. giarettai, Pseudopaludicola canga, P. atragula, and Pseudopaludicola sp. 2) and 2n = 16 (Pseudopaludicola mystacalis), there are no evident axial or juxta‐axonemal fibers, but a paraxonemal rod with a thick undulating membrane, which is shorter than that found among Pseudopaludicola species. The ultrastructural morphological differences observed in the spermatozoa of these species may be phylogenetically informative, given that they coincide with the consensus phylogeny of the group and appear to represent a progressive simplification of the spermatozoon. J. Morphol. 276:1495–1504, 2015. © 2015 Wiley Periodicals, Inc.     

The Tat system of Gram-positive bacteria

The twin-arginine protein translocation (Tat) system has a unique ability to translocate folded and co-factor-containing proteins across lipid bilayers. The Tat pathway is present in bacteria, archaea and in the thylakoid membranes of chloroplasts and, depending on the organism and environmental conditions, it can be deemed important for cell survival, virulence or bioproduction. This review provides an overview of the current understanding of the Tat system with specific focus on Gram-positive bacteria. The ‘universal minimal Tat system’ is composed of a TatA and a TatC protein. However, this pathway is more commonly composed of two TatA-like proteins and one TatC protein. Often the TatA-like proteins have diverged to have two different functions and, in this case, the second TatA-like protein is usually referred to as TatB. The correct folding and/or incorporation of co-factors are requirements for translocation, and the known quality control mechanisms are examined in this review. A number of examples of crosstalk between the Tat system and other protein transport systems, such as the Sec–YidC translocon and signal peptidases or sheddases are also discussed. Further, an overview of specific Gram-positive bacterial Tat systems found in monoderm and diderm species is detailed. Altogether, this review highlights the unique features of Gram-positive bacterial Tat systems and pinpoints key questions that remain to be addressed in future research. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.