269 research outputs found

    Cell Motility Dynamics: A Novel Segmentation Algorithm to Quantify Multi-Cellular Bright Field Microscopy Images

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    Confocal microscopy analysis of fluorescence and morphology is becoming the standard tool in cell biology and molecular imaging. Accurate quantification algorithms are required to enhance the understanding of different biological phenomena. We present a novel approach based on image-segmentation of multi-cellular regions in bright field images demonstrating enhanced quantitative analyses and better understanding of cell motility. We present MultiCellSeg, a segmentation algorithm to separate between multi-cellular and background regions for bright field images, which is based on classification of local patches within an image: a cascade of Support Vector Machines (SVMs) is applied using basic image features. Post processing includes additional classification and graph-cut segmentation to reclassify erroneous regions and refine the segmentation. This approach leads to a parameter-free and robust algorithm. Comparison to an alternative algorithm on wound healing assay images demonstrates its superiority. The proposed approach was used to evaluate common cell migration models such as wound healing and scatter assay. It was applied to quantify the acceleration effect of Hepatocyte growth factor/scatter factor (HGF/SF) on healing rate in a time lapse confocal microscopy wound healing assay and demonstrated that the healing rate is linear in both treated and untreated cells, and that HGF/SF accelerates the healing rate by approximately two-fold. A novel fully automated, accurate, zero-parameters method to classify and score scatter-assay images was developed and demonstrated that multi-cellular texture is an excellent descriptor to measure HGF/SF-induced cell scattering. We show that exploitation of textural information from differential interference contrast (DIC) images on the multi-cellular level can prove beneficial for the analyses of wound healing and scatter assays. The proposed approach is generic and can be used alone or alongside traditional fluorescence single-cell processing to perform objective, accurate quantitative analyses for various biological applications

    Quantum Control of Photodissociation via Manipulation of Bond Softening

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    We present a method to control photodissociation by manipulating the bond softening mechanism occurring in strong shaped laser fields, by varying the chirp sign and magnitude of an ultra-short laser pulse. Manipulation of bond-softening is experimentally demonstrated for strong field (795 nm, 10^12 - 10^13 W/cm^2) photodissociation of H2+, exhibiting substantial increase of dissociation by positively chirped pulses with respect to both negatively chirped and transform limited pulses. The measured kinetic energy release and angular distributions are used to quantify the degree of control of dissociation. The control mechanism is attributed to the interplay of dynamic alignment and chirped light induced potential curves.Comment: 4 pages, 4 figure

    Pre-hospital stroke monitoring past, present, and future: a perspective

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    Integrated brain-machine interface signifies a transformative advancement in neurological monitoring and intervention modalities for events such as stroke, the leading cause of disability. Historically, stroke management relied on clinical evaluation and imaging. While today’s stroke landscape integrates artificial intelligence for proactive clinical decision-making, mainly in imaging and stroke detection, it depends on clinical observation for early detection. Cardiovascular monitoring and detection systems, which have become standard throughout healthcare and wellness settings, provide a model for future cerebrovascular monitoring and detection. This commentary reviews the progression of continuous stroke monitoring, spotlighting contemporary innovations and prospective avenues, and emphasizes the influential roles of cutting-edge technologies in shaping stroke care

    Eficácia do glufosinato de amônio associado com outros herbicidas na cultura do algodão Liberty Link®

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    The objective of this study was to evaluate the efficiency of ammonium-glufosinate in management programs for weeds in cotton crop FiberMax 966 Liberty Link® genotype. The experiment was installed in experimental area of Paiaguás Farm, located in municipality of Diamantino, Mato Grosso State. The experiment was conducted in a randomized block design with eight treatments and four replications. For weeds efficient management in FiberMax 966 LL genotype, the application of herbicide treatment in pre-emergence may reduce up to two post-emergence applications with no significant losses in production, but the pre-emergence treatment needs to be effective. If the application of a herbicide treatment in pre-emergence is not possible, the use of three sequential applications of ammonium-glufosinate (0.5, 0.4, 0.6 kg ha-1) at 10, 25 and 40 days after crop emergence (DAE) result in similar information. In the conditions that the experiment was conducted, all herbicide treatments were selective to the crop, without significant differences in bolls number and yield.Objetivou-se com este trabalho avaliar a eficiência do glufosinato de amônio em programas de manejo de plantas daninhas no algodoeiro para a cultivar FiberMax 966 Liberty Link®. O experimento foi instalado na área experimental da Fazenda Paiaguás, localizada no município de Diamantino-MT. O experimento foi realizado em delineamento de blocos ao acaso com 8 tratamentos e 4 repetições. Para o manejo eficiente de plantas daninhas na cultivar FiberMax 966 LL, o emprego de um tratamento herbicida em pré-emergência pode reduzir até duas aplicações em pós-emergência sem que haja perdas significativas na produção, desde que o tratamento em pré-emergência seja eficiente. Caso a aplicação de um tratamento herbicida em pré-emergência não seja possível, a utilização de três aplicações sequenciais de glufosinato de amônio (0,5; 0,4; 0,6 kg ha-1) aos 10, 25 e 40 dias após emergência da cultura (DAE) resultaram em resultados semelhantes. Nas condições em que o experimento foi realizado, todos os tratamentos herbicidas foram seletivos à cultura, não sendo constatadas diferenças significativas no número de capulhos e na produtividade

    Metabolic networking in Brunfelsia calycina petals after flower opening

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    Brunfelsia calycina flowers change colour from purple to white due to anthocyanin degradation, parallel to an increase in fragrance and petal size. Here it was tested whether the production of the fragrant benzenoids is dependent on induction of the shikimate pathway, or if they are formed from the anthocyanin degradation products. An extensive characterization of the events taking place in Brunfelsia flowers is presented. Anthocyanin characterization was performed using ultraperfomance liquid chromatography–quadrupole time of flight–tandem mass specrometry (UPLC-QTOF-MS/MS). Volatiles emitted were identified by headspace solid phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS). Accumulated proteins were identified by 2D gel electrophoresis. Transcription profiles were characterized by cross-species hybridization of Brunfelsia cDNAs to potato cDNA microarrays. Identification of accumulated metabolites was performed by UPLC-QTOF-MS non-targeted metabolite analysis. The results include characterization of the nine main anthocyanins in Brunfelsia flowers. In addition, 146 up-regulated genes, 19 volatiles, seven proteins, and 17 metabolites that increased during anthocyanin degradation were identified. A multilevel analysis suggests induction of the shikimate pathway. This pathway is the most probable source of the phenolic acids, which in turn are precursors of both the benzenoid and lignin production pathways. The knowledge obtained is valuable for future studies on degradation of anthocyanins, formation of volatiles, and the network of secondary metabolism in Brunfelsia and related species

    When all computers shut down: the clinical impact of a major cyber-attack on a general hospital

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    ImportanceHealthcare organizations operate in a data-rich environment and depend on digital computerized systems; thus, they may be exposed to cyber threats. Indeed, one of the most vulnerable sectors to hacks and malware is healthcare. However, the impact of cyberattacks on healthcare organizations remains under-investigated.ObjectiveThis study aims to describe a major attack on an entire medical center that resulted in a complete shutdown of all computer systems and to identify the critical actions required to resume regular operations.SettingThis study was conducted on a public, general, and acute care referral university teaching hospital.MethodsWe report the different recovery measures on various hospital clinical activities and their impact on clinical work.ResultsThe system malfunction of hospital computers did not reduce the number of heart catheterizations, births, or outpatient clinic visits. However, a sharp drop in surgical activities, emergency room visits, and total hospital occupancy was observed immediately and during the first postattack week. A gradual increase in all clinical activities was detected starting in the second week after the attack, with a significant increase of 30% associated with the restoration of the electronic medical records (EMR) and laboratory module and a 50% increase associated with the return of the imaging module archiving. One limitation of the present study is that, due to its retrospective design, there were no data regarding the number of elective internal care hospitalizations that were considered crucial.Conclusions and relevanceThe risk of ransomware cyberattacks is growing. Healthcare systems at all levels of the hospital should be aware of this threat and implement protocols should this catastrophic event occur. Careful evaluation of steady computer system recovery weekly enables vital hospital function, even under a major cyberattack. The restoration of EMR, laboratory systems, and imaging archiving modules was found to be the most significant factor that allowed the return to normal clinical hospital work

    Roadmap on label-free super-resolution imaging

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    Label-free super-resolution (LFSR) imaging relies on light-scattering processes in nanoscale objects without a need for fluorescent (FL) staining required in super-resolved FL microscopy. The objectives of this Roadmap are to present a comprehensive vision of the developments, the state-of-the-art in this field, and to discuss the resolution boundaries and hurdles that need to be overcome to break the classical diffraction limit of the label-free imaging. The scope of this Roadmap spans from the advanced interference detection techniques, where the diffraction-limited lateral resolution is combined with unsurpassed axial and temporal resolution, to techniques with true lateral super-resolution capability that are based on understanding resolution as an information science problem, on using novel structured illumination, near-field scanning, and nonlinear optics approaches, and on designing superlenses based on nanoplasmonics, metamaterials, transformation optics, and microsphere-assisted approaches. To this end, this Roadmap brings under the same umbrella researchers from the physics and biomedical optics communities in which such studies have often been developing separately. The ultimate intent of this paper is to create a vision for the current and future developments of LFSR imaging based on its physical mechanisms and to create a great opening for the series of articles in this field
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