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Thomas H Segall-Shapiro, Eduardo D Sontag, Christopher A Voigt
The internal environment of growing cells is variable and dynamic, making it difficult to introduce reliable parts, such as promoters, for genetic engineering. Here, we applied control-theoretic ideas to design promoters that maintained constant levels of expression at any copy number. Theory predicts that independence to copy number can be achieved by using an incoherent feedforward loop (iFFL) if the negative regulation is perfectly non-cooperative. We engineered iFFLs into Escherichia coli promoters using transcription-activator-like effectors (TALEs)...
March 19, 2018: Nature Biotechnology
Ryan Rosenberry, Susie Chung, Michael D Nelson
Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. Reactive hyperemia (in response to a brief period of tissue ischemia) is an independent predictor of cardiovascular events and provides important insight into vascular health and vasodilatory capacity. Skeletal muscle oxidative capacity is equally important in health and disease, as it determines the energy supply for myocellular processes. Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess each of these major clinical endpoints (reactive hyperemia, neurovascular coupling, and muscle oxidative capacity) during a single clinic or laboratory visit...
February 20, 2018: Journal of Visualized Experiments: JoVE
Samuel D Clark, Rachel Mikofsky, Jacqueline Lawson, David Sulzer
Multiphoton microscopy has been widely adapted for imaging neurons in vivo. Repeated imaging requires implantation of a cranial window or repeated thinning of the skull. Cranial window surgery is typically performed with a high speed rotary drill, and many investigators find it challenging to prevent the drill from damaging the delicate dura and blood vessels. Extensive training and practice is required to remove the bone without damage to underlying tissue and thus cranial window surgery can be difficult, time consuming, and produce tissue damage...
March 2, 2018: Journal of Visualized Experiments: JoVE
Xing Chen, Detlef Wolf, Juliane Siebourg-Polster, Christian Czech, Ulrike Bonati, Dirk Fischer, Omar Khwaja, Martin Strahm
Progressive and irreversible muscle atrophy characterizes Spinal Muscular Atrophy (SMA) and other similar muscle disorder diseases. Objective assessment of muscle functions is an essential and important, although challenging, prerequisite for successful clinical trials. Current clinical rating scales restrain the movement abnormalities to certain predefined coarse-grained individual items. The Kinect 3-D sensor has emerged as a low-cost and portable motion sensing technology used to capture and track people's movement in many medical and research fields...
February 12, 2018: Journal of Visualized Experiments: JoVE
Tara Nietzold, Bradley M West, Michael Stuckelberger, Barry Lai, Stefan Vogt, Mariana I Bertoni
The quantification of X-ray fluorescence (XRF) microscopy maps by fitting the raw spectra to a known standard is crucial for evaluating chemical composition and elemental distribution within a material. Synchrotron-based XRF has become an integral characterization technique for a variety of research topics, particularly due to its non-destructive nature and its high sensitivity. Today, synchrotrons can acquire fluorescence data at spatial resolutions well below a micron, allowing for the evaluation of compositional variations at the nanoscale...
February 17, 2018: Journal of Visualized Experiments: JoVE
Jonathan T Ting, Brian R Lee, Peter Chong, Gilberto Soler-Llavina, Charles Cobbs, Christof Koch, Hongkui Zeng, Ed Lein
This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology...
February 26, 2018: Journal of Visualized Experiments: JoVE
Andrew K Fuller, Benjamin D Bice, Ashlee R Venancio, Olivia M Crowley, Ambur M Staab, Stephanie J Georges, Julio R Hidalgo, Annika V Warncke, Melinda L Angus-Hill
Several recent studies have illustrated the beneficial effects of living in an enriched environment on improving human disease. In mice, environmental enrichment (EE) reduces tumorigenesis by activating the mouse immune system, or affects tumor bearing animal survival by stimulating the wound repair response, including improved microbiome diversity, in the tumor microenvironment. Provided here is a detailed procedure to assess the effects of environmental enrichment on the biodiversity of the microbiome in a mouse colon tumor model...
February 28, 2018: Journal of Visualized Experiments: JoVE
Michael D Guthrie, Donald L Gilbert, David A Huddleston, Ernest V Pedapati, Paul S Horn, Stewart H Mostofsky, Steve W Wu
We describe the development of a reproducible, child-friendly motor response inhibition task suitable for online Transcranial Magnetic Stimulation (TMS) characterization of primary motor cortex (M1) excitability and inhibition. Motor response inhibition prevents unwanted actions and is abnormal in several neuropsychiatric conditions. TMS is a non-invasive technology that can quantify M1 excitability and inhibition using single- and paired-pulse protocols and can be precisely timed to study cortical physiology with high temporal resolution...
February 8, 2018: Journal of Visualized Experiments: JoVE
Riti Sharan, Hee-Jeong Yang, Preeti Sule, Jeffrey D Cirillo
Reporter enzyme fluorescence (REF) utilizes substrates that are specific for enzymes present in target organisms of interest for imaging or detection by fluorescence or bioluminescence. We utilize BlaC, an enzyme expressed constitutively by all M. tuberculosis strains. REF allows rapid quantification of bacteria in lungs of infected mice. The same group of mice can be imaged at many time points, greatly reducing costs, enumerating bacteria more quickly, allowing novel observations in host-pathogen interactions, and increasing statistical power, since more animals per group are readily maintained...
February 26, 2018: Journal of Visualized Experiments: JoVE
Jianhua Ren, Yadwinder S Mann, Yuntao Zhang, Michael D Browne
Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have been thought of as a type of molecular information storage. Mass spectrometry analysis has been considered the method of choice for sequencing peptoids. Peptoids can be synthesized via solid phase chemistry using a repeating two-step reaction cycle. Here we present a method to manually synthesize oligo-peptoids and to analyze the sequence of the peptoids using tandem mass spectrometry (MS/MS) techniques...
February 21, 2018: Journal of Visualized Experiments: JoVE
Madeleine S Durkee, Landon D Nash, Fatemeh Nooshabadi, Jeffrey D Cirillo, Duncan J Maitland, Kristen C Maitland
The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By replicating the imaging environment, costly animal experiments to validate a technique may be circumvented. Predicting and optimizing the performance of in vivo and ex vivo imaging techniques requires testing on samples that are optically similar to tissues of interest. Tissue-mimicking optical phantoms provide a standard for evaluation, characterization, or calibration of an optical system...
February 12, 2018: Journal of Visualized Experiments: JoVE
Mireille Laforge, Ricardo Silvestre, Vasco Rodrigues, Julie Garibal, Laure Campillo-Gimenez, Shahul Mouhamad, Valérie Monceaux, Marie-Christine Cumont, Henintsoa Rabezanahary, Alain Pruvost, Anabela Cordeiro-da-Silva, Bruno Hurtrel, Guido Silvestri, Anna Senik, Jérôme Estaquier
Apoptosis has been proposed as a key mechanism responsible for CD4+ T cell depletion and immune dysfunction during HIV infection. We demonstrated that Q-VD-OPH, a caspase inhibitor, inhibits spontaneous and activation-induced death of T cells from SIV-infected rhesus macaques (RMs). When administered during the acute phase of infection, Q-VD-OPH was associated with (a) reduced levels of T cell death, (b) preservation of CD4+/CD8+ T cell ratio in lymphoid organs and in the gut, (c) maintenance of memory CD4+ T cells, and (d) increased specific CD4+ T cell response associated with the expression of cytotoxic molecules...
March 19, 2018: Journal of Clinical Investigation
Marija D Ivanovic, Jovana Petrovic, Andrej Savic, Goran Gligoric, Marjan Miletic, Miodrag Vukcevic, Bosko Bojovic, Ljupco Hadzievski, Tom D P Allsop, David J Webb
The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple negative consequences. Our objective is to test the possibility of using chest-wall motion measured by an optical fibre-grating sensor as a more accurate non-invasive ventilator triggering mechanism.
 Approach: The basic premise of our approach is that the measurement accuracy can be improved by using a triggering signal that precedes pneumatic triggering in the neuro-ventilatory coupling sequence...
March 19, 2018: Physiological Measurement
Igor Gayduchenko, Georgy Fedorov, Maxim Moskotin, Denis Yagodkin, Sergey Seliverstov, Gregory N Gol'tsman, Alexander Kuntsevich, Maxim Rybin, Elena D Obraztsova, Vladimir Leiman, Michael S Shur, Taiichi Otsuji, Victor Ryzhii
We report on the sub-THz (129 - 450 GHz) photoresponse of devices based on single layer graphene and graphene nanoribbons with asymmetric source and drain (vanadium and gold) contacts. Vanadium forms a barrier at the graphene interface while gold forms an Ohmic contact. We find that at low temperatures (77K) the detector responsivity rises with the increasing frequency of the incident sub-THz radiation. We interpret this result as a manifestation of a plasmonic effect in the devices with the relatively long plasmonic wavelengths...
March 19, 2018: Nanotechnology
Ahmad Yaseen, Sa'd Suleiman, Omar Abu Zenah, Adham Abu Taha
BACKGROUND: Red blood-cell transfusion has greatly reduced the mortality and morbidity in multiply transfused patients with thalassaemia and sickle cell disease. However, this can result in red blood-cell isoimmunisation with autoantibodies and alloantibodies, which can lead to serious complications such as delayed haemolytic transfusion reaction. The aim of this study was to assess the frequency and types of alloantibodies in multiply transfused patients living in the north of the West Bank...
February 21, 2018: Lancet
Aeysha Chaudhry, Shakoor Hajat, Najwa Rizkallah, Ala'a Abu-Rub
BACKGROUND: Vitamin A and vitamin D are essential for a child's growth and development. However, research on micronutrients in the occupied Palestinian territory is scarce. The aim of this study was to ascertain the prevalence and risk factors of vitamin A and vitamin D deficiencies in children living in the occupied Palestinian territory. METHODS: The Palestinian Micronutrient Survey in 2013 measured concentrations of vitamin A in 1054 children (569 children in the West Bank and 485 children in the Gaza Strip) and vitamin D in 150 children (75 children in the West Bank and 75 children in the Gaza Strip)...
February 21, 2018: Lancet
F Roviello, K Polom, A D'Ignazio, V Pascale, D Marrelli
No abstract text is available yet for this article.
March 2018: European Journal of Cancer
V Damarla, D Dobrosotskaya, F Siddiqui, I Wollner, M Raoufi, J Li, D Kwon, G Khan
No abstract text is available yet for this article.
March 2018: European Journal of Cancer
A Chiappa, E Bertani, N Fazio, D Foschi, M Venturino, C Ferrari, L Macone, M Tullii, R Biffi
No abstract text is available yet for this article.
March 2018: European Journal of Cancer
F Roviello, K Polom, A D'Ignazio, V Pascale, D Marrelli
No abstract text is available yet for this article.
March 2018: European Journal of Cancer
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