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J Am Chem Soc ; 142(6): 2968-2974, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31968164


In situ amplification methods, such as hybridization chain reaction, are valuable tools for mapping the spatial distribution and subcellular location of target analytes. However, the live-cell applications of these methods are still limited due to challenges in the probe delivery, degradation, and cytotoxicity. Herein, we report a novel genetically encoded in situ amplification method to noninvasively image the subcellular location of RNA targets in living cells. In our system, a fluorogenic RNA reporter, Broccoli, was split into two nonfluorescent fragments and conjugated to the end of two RNA hairpin strands. The binding of one target RNA can then trigger a cascaded hybridization between these hairpin pairs and thus activate multiple Broccoli fluorescence signals. We have shown that such an in situ amplified strategy can be used for the sensitive detection and location imaging of various RNA targets in living bacterial and mammalian cells. This new design principle provides an effective and versatile platform for tracking various intracellular analytes.

Proc Natl Acad Sci U S A ; 116(43): 21427-21437, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31601737


Pharmacology and optogenetics are widely used in neuroscience research to study the central and peripheral nervous systems. While both approaches allow for sophisticated studies of neural circuitry, continued advances are, in part, hampered by technology limitations associated with requirements for physical tethers that connect external equipment to rigid probes inserted into delicate regions of the brain. The results can lead to tissue damage and alterations in behavioral tasks and natural movements, with additional difficulties in use for studies that involve social interactions and/or motions in complex 3-dimensional environments. These disadvantages are particularly pronounced in research that demands combined optogenetic and pharmacological functions in a single experiment. Here, we present a lightweight, wireless, battery-free injectable microsystem that combines soft microfluidic and microscale inorganic light-emitting diode probes for programmable pharmacology and optogenetics, designed to offer the features of drug refillability and adjustable flow rates, together with programmable control over the temporal profiles. The technology has potential for large-scale manufacturing and broad distribution to the neuroscience community, with capabilities in targeting specific neuronal populations in freely moving animals. In addition, the same platform can easily be adapted for a wide range of other types of passive or active electronic functions, including electrical stimulation.

Sci Adv ; 5(7): eaaw5296, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31281895


Studies of the peripheral nervous system rely on controlled manipulation of neuronal function with pharmacologic and/or optogenetic techniques. Traditional hardware for these purposes can cause notable damage to fragile nerve tissues, create irritation at the biotic/abiotic interface, and alter the natural behaviors of animals. Here, we present a wireless, battery-free device that integrates a microscale inorganic light-emitting diode and an ultralow-power microfluidic system with an electrochemical pumping mechanism in a soft platform that can be mounted onto target peripheral nerves for programmed delivery of light and/or pharmacological agents in freely moving animals. Biocompliant designs lead to minimal effects on overall nerve health and function, even with chronic use in vivo. The small size and light weight construction allow for deployment as fully implantable devices in mice. These features create opportunities for studies of the peripheral nervous system outside of the scope of those possible with existing technologies.

Sci Total Environ ; 551-552: 143-54, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26878632


This paper presents a system for determining the evaluation and gradation indices of groundwater pollution intensity (GPI). Considering the characteristics of the vadose zone and pollution sources, the system decides which anti-seepage measures should be implemented at the contaminated site. The pollution sources hazards (PSH) and groundwater intrinsic vulnerability (GIV) are graded by the revised Nemerow Pollution Index and an improved DRTAS model, respectively. GPI is evaluated and graded by a double-sided multi-factor coupling model, which is constructed by the matrix method. The contaminated sites are categorized as prior, ordinary, or common sites. From the GPI results, we develop guiding principles for preventing and removing pollution sources, procedural interruption and remediation, and end treatment and monitoring. Thus, we can select appropriate prevention and control technologies (PCT). To screen the technological schemes and optimize the traditional analytical hierarchy process (AHP), we adopt the technique for order preference by the similarity to ideal solution (TOPSIS) method. Our GPI approach and PCT screening are applied to three types of pollution sites: the refuse dump of a rare earth mine development project (a potential pollution source), a chromium slag dump, and a landfill (existing pollution sources). These three sites are identified as ordinary, prior, and ordinary sites, respectively. The anti-seepage materials at the refuse dump should perform as effectively as a 1.5-m-thick clay bed. The chromium slag dump should be preferentially treated by soil flushing and in situ chemical remediation. The landfill should be treated by natural attenuation technology. The proposed PCT screening approach was compared with conventional screening methods results at the three sites and proved feasible and effective. The proposed method can provide technical support for the monitoring and management of groundwater pollution in China.

Monitoramento Ambiental , Água Subterrânea/química , Poluentes Químicos da Água/análise , China , Poluição Química da Água/estatística & dados numéricos
Acta Crystallogr E Crystallogr Commun ; 71(Pt 4): 414-7, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26029403


The crystal structures are reported of the isomeric compounds 2-(4-nitro-phen-yl)-3-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one, (I), and 2-(2-nitro-phen-yl)-3-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one, (II), both C20H14N2O3S, being the para-nitro and ortho-nitro forms, respectively, the meta-form of which is known [Yennawar et al. (2013). Acta Cryst. E69, o1679]. The six-membered thia-zone ring fused with a benzene ring displays a screw-boat conformation with a total puckering amplitude of 0.627 (1) Šin (I), and a near screw-boat conformation with a total puckering amplitude of 0.600 (1) Šin (II). The dihedral angles between the planes of the substituent nitrophenyl and phenyl and rings with the benzene ring of the parent benzo-thia-zone moiety are 75.93 (5) and 82.61 (5)° [in (I)], and 76.79 (6) and 71.66 (6)° [in (II)]. Weak inter-molecular C-H⋯O hydrogen-bonding inter-actions between aromatic H-atom donors and both a nitro-O atom and a thia-zone O-atom acceptor in (I) and a thia-zone O atom in (II) are present, forming in (I) a centrosymmetric 22-membered cyclic dimer which is extended through a similar inversion-related 14-membered cyclic hydrogen-bonding association into a zigzag chain structure extending along c. In (II), a single inter-molecular C-H⋯O hydrogen bond gives a chain structure extending along b. In addition, weak C-H⋯π inter-actions are present in both structures [minimum C⋯ring-centroid separations = 3.630 (2) and 3.581 (2) Å, respectively].