f Serotyping forms the basis of national and international surveillance networks for Salmonella, one of the most prevalent foodborne pathogens worldwide (1-3). Public health microbiology is currently being transformed by whole-genome sequencing (WGS), which opens the door to serotype determination using WGS data. SeqSero (www.denglab.info/SeqSero) is a novel Webbased tool for determining Salmonella serotypes using high-throughput genome sequencing data. SeqSero is based on curated databases of Salmonella serotype determinants (rfb gene cluster, fliC and fljB alleles) and is predicted to determine serotype rapidly and accurately for nearly the full spectrum of Salmonella serotypes (more than 2,300 serotypes), from both raw sequencing reads and genome assemblies. The performance of SeqSero was evaluated by testing (i) raw reads from genomes of 308 Salmonella isolates of known serotype; (ii) raw reads from genomes of 3,306 Salmonella isolates sequenced and made publicly available by GenomeTrakr, a U.S. national monitoring network operated by the Food and Drug Administration; and (iii) 354 other publicly available draft or complete Salmonella genomes. We also demonstrated Salmonella serotype determination from raw sequencing reads of fecal metagenomes from mice orally infected with this pathogen. SeqSero can help to maintain the well-established utility of Salmonella serotyping when integrated into a platform of WGS-based pathogen subtyping and characterization. Salmonella is the most prevalent foodborne pathogen in the United States, causing 1.2 million cases of illness annually and the largest health burden among all bacterial pathogens (4). The U.S. National Salmonella Surveillance System has been built upon serotyping in public health laboratories, a subtyping method traditionally performed through the agglutination of Salmonella cells with specific antisera that detect lipopolysaccharide O antigen and flagellar H antigens. Specific combinations of O and H antigenic types represent serotypes (or serovars). More than 2,500 Salmonella serotypes have been described in the White-Kauffmann-Le Minor scheme (5, 6). The phenotypic determination of serotypes is labor-intensive and time-consuming (taking at least 2 days), which has led to the development of genetic methods for serotype determination (7,8). These methods generally use two categories of targets for serotype determination: (i) indirect targets, requiring the use of random surrogate genomic markers associated with particular serotypes, and (ii) direct targets, requiring the use of genetic determinants of serotypes, including the rfb gene cluster responsible for somatic (O) group synthesis (9, 10) and the fliC (11) and fljB (12) genes encoding the two flagellar antigens present in Salmonella. The latter approach has the advantage of determining serotypes using the same markers as the phenotypic method, providing continuity between the serotypes determined by phenotypic and genetic markers (13,14). While this approach may result in distinct genetic lineages bei...

A fast silicon-graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm is proposed and realized by introducing an ultra-thin wide silicon-on-insulator ridge core region with a narrow metal cap. With this novel design, the light absorption in graphene is enhanced while the metal absorption loss is reduced simultaneously, which helps greatly improve the responsivity as well as shorten the absorption region for achieving fast responses. Furthermore, metal-graphenemetal sandwiched electrodes are introduced to reduce the metal-graphene contact resistance, which is also helpful for improving the response speed. When the photodetector operates at 2 μm, the measured 3dB-bandwidth is >20 GHz (which is limited by the experimental setup) while the 3dB-bandwith calculated from the equivalent circuit with the parameters extracted from the measured S 11 is as high as ~100 GHz. To the best of our knowledge, it is the first time to report the waveguide photodetector at 2 μm with a 3dB-bandwidth over 20 GHz. Besides, the present photodetectors also work very well at 1.55 μm. The measured responsivity is about 0.4 A/W under a bias voltage of −0.3 V for an optical power of 0.16 mW, while the measured 3dB-bandwidth is over 40 GHz (limited by the test setup) and the 3 dB-bandwidth estimated from the equivalent circuit is also as high as ~100 GHz, which is one of the best results reported for silicon-graphene photodetectors at 1.55 μm.

Nanogel-based nanoplatforms have become a tremendously promising system of drug delivery. Nanogels constructed by chemical crosslinking or physical self-assembly exhibit the ability to encapsulate hydrophilic or hydrophobic therapeutics, including but not limited to small-molecule compounds and proteins, DNA/RNA sequences, and even ultrasmall nanoparticles, within their 3D polymer network. The nanosized nature of the carriers endows them with a specific surface area and inner space, increasing the stability of loaded drugs and prolonging their circulation time. Reactions or the cleavage of chemical bonds in the structure of drug-loaded nanogels have been shown to trigger the controlled or sustained drug release. Through the design of specific chemical structures and different methods of production, nanogels can realize diverse responsiveness (temperature-sensitive, pH-sensitive and redox-sensitive), and enable the stimuli-responsive release of drugs in the microenvironments of various diseases. To improve therapeutic outcomes and increase the precision of therapy, nanogels can be modified by specific ligands to achieve active targeting and enhance the drug accumulation in disease sites. Moreover, the biomembrane-camouflaged nanogels exhibit additional intelligent targeted delivery features. Consequently, the targeted delivery of therapeutic agents, as well as the combinational therapy strategy, result in the improved efficacy of disease treatments, though the introduction of a multifunctional nanogel-based drug delivery system.

Silicon photonics is being extended from the near-infrared window of 1.3-1.5 µm for optical fiber communications to the mid-infrared (mid-IR) wavelength-band of 2 µm or longer for satisfying the increasing demands in many applications. Mid-IR waveguide photodetectors on silicon have attracted intensive attention as one of the indispensable elements for various photonic systems. However, when combining traditional semiconductor materials with silicon, there are some challenges due to lattice mismatch and thermal expansion mismatch. As an alternative, two-dimensional (2D) materials provide a new and promising option for enabling active photonic devices on silicon. Here black-phosphorus (BP) thin films with optimized medium thicknesses (40 nm) are introduced as the active material for light absorption and silicon/BP hybrid ridge waveguide photodetectors at 2 µm are demonstrated with a high responsivity of 306.7 mA W −1 at a low bias voltage of 0.4 V. The 3 dB-bandwidth is up to 1.33 GHz and an experiment of a 4.0 Gbit s −1 data receiving is also demonstrated.

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