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Traditional dual-frequency FSS based on double-hexagonal-ring is difficult to remove the grating lobes. To solve this problem, a novel dual-band FSS is proposed. The frequency response characteristics of the FSS for different polarizations and different incident angles are simulated. The results show that the novel FSS has good angle stability and polarization stability. The parasitic resonance is also eliminated. The novel dual-band FSS has great practical value in the fields of satellite communications.

Phase-contrast microscopy converts the phase shift of light passing through a transparent specimen, e.g., a biological cell, into brightness variations in an image. This ability to observe structures without destructive fixation or staining has been widely utilized for applications in materials and life sciences. Despite these advantages, phase-contrast microscopy lacks the ability to reveal molecular information. To address this gap, we developed a bond-selective transient phase (BSTP) imaging technique that excites molecular vibrations by infrared light, resulting in a transient change in phase shift that can be detected by a diffraction phase microscope. By developing a time-gated pump–probe camera system, we demonstrate BSTP imaging of live cells at a 50 Hz frame rate with high spectral fidelity, sub-microsecond temporal resolution, and sub-micron spatial resolution. Our approach paves a new way for spectroscopic imaging investigation in biology and materials science., Imaging: probing chemical bonds A phase imaging technique that provides spectroscopic chemical information could bring new opportunities for studying biology and materials science. Delong Zhang, Lu Lan, and coworkers from Boston, Illinois and Shanghai have developed a scheme called bond-selective transient phase (BSTP) imaging. The approach uses nanosecond pulses of mid-infrared pump laser light to excite molecular vibrations in the sample. The mid-infrared light absorption causes a small temperature change in the sample which results in a change of refractive index and thus a transient phase shift, which is read out by a burst of visible probe pulses and a CMOS camera. Tests with samples including a thin oil film, polyurethane beads, living cells, and the interface between two liquids (olive oil and dimethyl sulfoxide) indicate that BSTP imaging can operate with sub-microsecond temporal resolution and sub-micrometer spatial resolution.

Ultrasound has been recently explored as a new modality for neural modulation. However, one of the challenges in ultrasound neural modulation is that delivery of transcranial ultrasound would inevitably go through the skull, and eventually reach the cochlear through bone transduction. Moreover, the presence of skull will compromise ultrasound focus, resulting in poor spatial resolution. Here, we developed a miniaturized Fiber-Optoacoustic Converter (FOC), which has a diameter of 600 μm, and can convert nano-second laser pulses into omni-directional acoustic waves through the optoacoustic effect. The ball shaped FOC is composed of one ZnO /epoxy based diffusion layer and two graphite/epoxy based absorption layer. The radiofrequency spectrum of the generated US frequency ranges from 0.1-5 MHz, with multiple frequencies peaks at 0.5, 1 and 3MHz. Using this FOC system, we show that ultrasound can directly activate individual cortical neuron in vitro, and generate intracellular Ca2+ transient without neural damage. We next demonstrate that the FOC is activates neurons with a radius of 500 μm around the FOC tip, delivering superior spatial resolution. The stimulation effect is specific to neurons, but not glial cells. We also provide evidence of transient mechanical disturbance of neuronal membrane as the mechanism for FOC neural modulation. Finally, we combine FOC neural modulation with electrophysiology, and achieve direct and spatially confined neural stimulation in vivo.

Generation of ultrasound using the optoacoustic effect has received increasing attention in the field of imaging and translational medicine. However, none of the current optoacoustic converters has been used for neural modulation. Here, we developed a miniaturized Fiber-Optoacoustic Converter (FOC), which has a diameter of 600 μm, and can convert nano-second laser pulses into acoustic waves through the optoacoustic effect. The ball shaped FOC is composed of one ZnO /epoxy based diffusion layer and two graphite/epoxy based absorption layer. The radiofrequency spectrum of the generated US frequency ranges from 0.1-5 MHz, with multiple frequencies peaks at 0.5, 1 and 3MHz. Compared to traditional ultrasound transducers, the FOC system has the advantages of miniaturized size, superior spatial resolution, and produces omnidirectional propagating acoustic wave. Using this FOC system, we show that ultrasound can directly activate individual cortical neuron in vitro with a radius of 500 μm around the FOC tip, and generate intracellular Ca2+ transient without neural damage. Neural activation is the consequence of mechanical disturbance of neuronal membrane, rather than direct laser or photothermal stimulation. Finally, we combine FOC neural modulation with electrophysiology, and achieve direct and spatially confined neural stimulation in vivo. The FOC system opens new possibilities to use optoacoustic effect as a new method for precise neural modulation.

Diarrheal disease is a complex syndrome that remains a leading cause of global childhood morbidity and mortality. The diagnosis of enteric pathogens in a timely and precise manner is important for making treatment decisions and informing public health policy, but accurate diagnosis is a major challenge in industrializing countries. Multiplex molecular diagnostic techniques may represent a significant improvement over classical approaches. We evaluated the Luminex xTAG gastrointestinal pathogen panel (GPP) assay for the detection of common enteric bacterial and viral pathogens in Vietnam. Microbiological culture and real-time PCR were used as gold standards. The tests were performed on 479 stool samples collected from people admitted to the hospital for diarrheal disease throughout Vietnam. Sensitivity and specificity were calculated for the xTAG GPP for the seven principal diarrheal etiologies. The sensitivity and specificity for the xTAG GPP were >88% for Shigella spp., Campylobacter spp., rotavirus, norovirus genotype 1/2 (GI/GII), and adenovirus compared to those of microbiological culture and/or real-time PCR. However, the specificity was low (∼60%) for Salmonella species. Additionally, a number of important pathogens that are not identified in routine hospital procedures in this setting, such as Cryptosporidium spp. and Clostridium difficile , were detected with the GPP. The use of the Luminex xTAG GPP for the detection of enteric pathogens in settings, like Vietnam, would dramatically improve the diagnostic accuracy and capacity of hospital laboratories, allowing for timely and appropriate therapy decisions and a wider understanding of the epidemiology of pathogens associated with severe diarrheal disease in low-resource settings.

Microwaves, which have a ∼10-cm wavelength, can penetrate deeper into tissue than photons, heralding exciting deep tissue applications such as modulation or imaging via the thermoacoustic effect. Thermoacoustic conversion efficiency is however very low, even with an exogenous contrast agent. We break this low-conversion limit, using a split ring resonator to effectively collect and confine the microwaves into a submillimeter hot spot for ultrasound emission and achieve a conversion efficiency over 2000 times higher than other reported thermoacoustic contrast agents. Importantly, the frequency of emitted ultrasound can be precisely tuned and multiplexed by modulation of the microwave pulses. Such performance is inaccessible by a piezoelectric-based transducer or a photoacoustic emitter and, therefore, split ring resonators open up new opportunities to study the frequency response of cells in ultrasonic biomodulation. For applications in deep tissue localization, a split ring resonator can be used as a wireless, battery-free ultrasound beacon placed under a breast phantom.

Widefield photothermal microscopy enables ultrafast chemical imaging at submicrometer spatial resolution., Infrared (IR) imaging has become a viable tool for visualizing various chemical bonds in a specimen. The performance, however, is limited in terms of spatial resolution and imaging speed. Here, instead of measuring the loss of the IR beam, we use a pulsed visible light for high-throughput, widefield sensing of the transient photothermal effect induced by absorption of single mid-IR pulses. To extract these transient signals, we built a virtual lock-in camera synchronized to the visible probe and IR light pulses with precisely controlled delays, allowing submicrosecond temporal resolution determined by the probe pulse width. Our widefield photothermal sensing microscope enabled chemical imaging at a speed up to 1250 frames/s, with high spectral fidelity, while offering submicrometer spatial resolution. With the capability of imaging living cells and nanometer-scale polymer films, widefield photothermal microscopy opens a new way for high-throughput characterization of biological and material specimens.

Low-intensity ultrasound is an emerging modality for neuromodulation. Yet, piezo-based transducers offer poor spatial confinement of excitation volume, often bigger than a few millimeters in diameter. In addition, the bulky size limits their implementation in a wearable setting and prevents integration with other experimental modalities. Here, we report spatially confined optoacoustic neural stimulation through a novel miniaturized Fiber-Optoacoustic Converter (FOC). The FOC has a diameter of 600 μm and generates omnidirectional ultrasound wave locally at the fiber tip through the optoacoustic effect. We show that the optoacoustic wave can directly activate individual cultured neurons and generate intracellular Ca2+ transients. The FOC activates neurons within a radius of 500 μm around the fiber tip, delivering superior spatial resolution over conventional piezo-based low-frequency transducers. Combining FOC with electrophysiology, direct and spatially confined neural stimulation of mouse brain is achieved in vivo.

We found a high transfer ratio of anti-nontyphoidal Salmonella (NTS) antibodies from mothers to infants. Furthermore, despite a high seroincidence of NTS in infants, maternally acquired antibodies provided protection from seroconversion. Therefore, we propose prenatal immunization against NTS as a possible strategy for protecting infants from NTS disease., Background Nontyphoidal Salmonella (NTS) organisms are a major cause of gastroenteritis and bacteremia, but little is known about maternally acquired immunity and natural exposure in infant populations residing in areas where NTS disease is highly endemic. Methods We recruited 503 pregnant mothers and their infants (following delivery) from urban areas in Vietnam and followed infants until they were 1 year old. Exposure to the dominant NTS serovars, Salmonella enterica serovars Typhimurium and Enteritidis, were assessed using lipopolysaccharide (LPS) O antigen–specific antibodies. Antibody dynamics, the role of maternally acquired antibodies, and NTS seroincidence rates were modeled using multivariate linear risk factor models and generalized additive mixed-effect models. Results Transplacental transfer of NTS LPS–specific maternal antibodies to infants was highly efficient. Waning of transplacentally acquired NTS LPS–specific antibodies at 4 months of age left infants susceptible to Salmonella organisms, after which they began to seroconvert. High seroincidences of S. Typhimurium and S. Enteritidis LPS were observed, and infants born with higher anti-LPS titers had greater plasma bactericidal activity and longer protection from seroconversion. Conclusions Although Vietnamese infants have extensive exposure to NTS, maternally acquired antibodies appear to play a protective role against NTS infections during early infancy. These findings suggest that prenatal immunization may be an appropriate strategy to protect vulnerable infants from NTS disease.

Water samples were collected to measure dissolved and particulate phosphorus species in order to examine the dynamics of phosphorus in the water column across the river&ndash, sea interface from the lower Dafengjiang River to the open Beibu Gulf. Dissolved inorganic phosphorus concentrations were as high as 0.90 &plusmn, 0.42 &mu, M in river water but decreased dramatically to as low as 0.02 &plusmn, 0.01 &mu, M in open coastal waters. Total dissolved phosphorus was largely measured in the form of dissolved inorganic phosphorus in river waters (58% &plusmn, 18%), whereas dissolved organic phosphorus became the predominant species (&gt, 90% on average) in open coastal waters. Total dissolved phosphorus was the dominant species, comprising 76% &plusmn, 16% of the total phosphorus, while total particulate phosphorus only comprised 24% &plusmn, 16% of the total phosphorus pool. Riverine inputs, physical and biological processes, and particulate phosphorus regeneration were the dominant factors responsible for the dynamic variations of phosphorus species in the study area. Based on a two-end-member mixing model, the biological uptake resulted in a dissolved inorganic phosphorus depletion of 0.12 &plusmn, 0.08 &mu, M in the coastal surface water, whereas the replenishment of dissolved inorganic phosphorus in the lower river from particle P regeneration and release resulted in an increase (0.19 &plusmn, 0.22 &mu, M) of dissolved inorganic phosphorus in the estuarine mixing region. The molar ratios of dissolved inorganic nitrogen to dissolved inorganic phosphorus and dissolved silicate to dissolved inorganic phosphorus in the open surface waters were &gt, 22, suggesting that, although the lower Dafengjiang River contained elevated concentrations of dissolved inorganic phosphorus, the northern Beibu Gulf was an overall P-limited coastal ecosystem.

Lumpectomy, also called breast-conserving surgery, has become the standard surgical treatment for early-stage breast cancer. However, accurately locating the tumor during a lumpectomy, especially when the lesion is small and nonpalpable, is a challenge. Such difficulty can lead to either incomplete tumor removal or prolonged surgical time, which result in high re-operation rates (~25%) and increased surgical costs. Here, we report a fiber optoacoustic guide (FOG) with augmented reality (AR) for sub-millimeter tumor localization and intuitive surgical guidance with minimal interference. The FOG is preoperatively implanted in the tumor. Under external pulsed light excitation, the FOG omnidirectionally broadcasts acoustic waves through the optoacoustic effect by a specially designed nano-composite layer at its tip. By capturing the acoustic wave, three ultrasound sensors on the breast skin triangulate the FOG tip’s position with 0.25-mm accuracy. An AR system with a tablet measures the coordinates of the ultrasound sensors and transforms the FOG tip’s position into visual feedback with, Optoacoustics: tumor localization Implanting an optoacoustic beacon into breast tumors provides surgeons with sub-millimeter localization accuracy when performing surgery. The system has been developed by Lu Lan from Boston University and coworkers. A fiber optoacoustic guide(FOG) which has a fiber tip coated with ZnO nanoparticles and graphite so that it is strongly light absorbing is implanted into the tumor prior to surgery. When exposed to pulsed light excitation the tip generates omnidirectional ultrasound waves due to the optoacoustic effect. The use of three ultrasound sensors to collect this signal makes it possible to accurately triangulate the exact location of the tumor during surgery. Combining the FOG with an augmented reality system offers surgeons an intuitive guidance aid which not only allows accurate and rapid tumor removal but will also help reduce the need for re-operation.

Many scientists do not believe that Maxwell’s fish eye mirror (MFEM) can provide perfect imaging even if there is a drain array around the imaging points. However, one microwave experiment found a ...

We identified high antimicrobial usage and high antimicrobial resistance in children hospitalized with bloody and/or mucoid bacteria-associated diarrhea. There was no clinical benefit of antimicrobial therapy in children with diarrhea; adequately powered randomized controlled trials are required., Background Pediatric diarrheal disease presents a major public health burden in low- to middle-income countries. The clinical benefits of empirical antimicrobial treatment for diarrhea are unclear in settings that lack reliable diagnostics and have high antimicrobial resistance (AMR). Methods We conducted a prospective multicenter cross-sectional study of pediatric patients hospitalized with diarrhea containing blood and/or mucus in Ho Chi Minh City, Vietnam. Clinical parameters, including disease outcome and treatment, were measured. Shigella, nontyphoidal Salmonella (NTS), and Campylobacter were isolated from fecal samples, and their antimicrobial susceptibility profiles were determined. Statistical analyses, comprising log-rank tests and accelerated failure time models, were performed to assess the effect of antimicrobials on disease outcome. Results Among 3166 recruited participants (median age 10 months; interquartile range, 6.5–16.7 months), one-third (1096 of 3166) had bloody diarrhea, and 25% (793 of 3166) were culture positive for Shigella, NTS, or Campylobacter. More than 85% of patients (2697 of 3166) were treated with antimicrobials; fluoroquinolones were the most commonly administered antimicrobials. AMR was highly prevalent among the isolated bacteria, including resistance against fluoroquinolones and third-generation cephalosporins. Antimicrobial treatment and multidrug resistance status of the infecting pathogens were found to have no significant effect on outcome. Antimicrobial treatment was significantly associated with an increase in the duration of hospitalization with particular groups of diarrheal diseases. Conclusions In a setting with high antimicrobial usage and high AMR, our results imply a lack of clinical benefit for treating diarrhea with antimicrobials; adequately powered randomized controlled trials are required to assess the role of antimicrobials for diarrhea.

Breast-conserving surgery is a well-accepted breast cancer treatment. However, it is still challenging for the surgeon to accurately localize the tumor during the surgery. Also, the guidance provided by current methods is 1 dimensional distance information, which is indirect and not intuitive. Therefore, it creates problems on a large re-excision rate, and a prolonged surgical time. To solve these problems, we have developed a fiber-delivered optoacoustic guide (OG), which mimics the traditional localization guide wire and is preoperatively placed into tumor mass, and an augmented reality (AR) system to provide real-time visualization on the location of the tumor with sub-millimeter variance. By a nano-composite light diffusion sphere and light absorbing layer formed on the tip of an optical fiber, the OG creates an omnidirectional acoustic source inside tumor mass under pulsed laser excitation. The optoacoustic signal generated has a high dynamic range (~ 58dB) and spreads in a large apex angle of 320 degrees. Then, an acoustic radar with three ultrasound transducers is attached to the breast skin, and triangulates the location of the OG tip. With an AR system to sense the location of the acoustic radar, the relative position of the OG tip inside the tumor to the AR display is calculated and rendered. This provides direct visual feedback of the tumor location to surgeons, which will greatly ease the surgical planning during the operation and save surgical time. A proof-of-concept experiment using a tablet and a stereo-vision camera is demonstrated and 0.25 mm tracking variance is achieved.

Dysregulation of lipid metabolism is associated with many diseases including cancer. Lipid droplet (LD), a ubiquitous organelle in mammalian cells, serves as a hub for lipid metabolism. Conventional assays on the measurement of lipid metabolism rely on the quantification of the lipid composition or amount. Such methods cannot distinguish LDs having different biofunctionalities in living cells, and thus could be inaccurate in measuring the instantaneous lipogenesis of the living cells. We applied label-free stimulated Raman scattering microscopy to quantify the LDs' spatial-temporal dynamics, which showed direct links to cellular lipid metabolisms and can separate LDs involved in different metabolic events. In human cancer cells, we found that changes in the maximum displacement of LDs reflected variations in cellular lipogenic activity, and changes in the average speed of LDs revealed alterations in LD size. The LD dynamics analysis allowed for more accurate measurement in the lipogenesis and LD dimensions, and can break the optical diffraction limit to detect small variation in lipid metabolism that was conventionally undetectable. By this method, we revealed changes in the lipogenic activity and LD sizes during glucose starvation of HeLa cells and transforming growth factor beta-induced epithelial-to-mesenchymal transition of SKOV-3 cells. This method opens a way to quantify lipid metabolism in living cells during cellular development and transition.

Surface sediments from 23 stations within the Maowei Sea intertidal flat were sampled for phosphorus (P) species analysis in December 2016. Different P forms were separated and quantified by a sequential extraction procedure. Results showed that the concentrations of total P (TP) ranged from 4.06 to 33. 33 μ m ol g − 1 , and inorganic P (IP) was the predominant chemical form of TP. Fe-bound P was the main chemical form of IP. Terrestrial inputs, biological processes, and particle size were responsible for the distribution characteristics of different P species. In addition to detrital P, regeneration and transformation occured among different P forms in the intertidal surface sediments. The principal component analysis reflected the importance of organic matter in the binding of various P species to fine-grained sediments. Sedimentary organic carbon to P ratios were > 106, and suggested that organic matter in the intertidal sediments were mainly derived from terrestrial sources or contain mostly reworked organic matter. Organic carbon to reactive P ratios were 29 − 90, suggesting efficient sequestration of inorganic P in sediments. Potential bioavailable P represented a significant proportion of the sedimentary P pool, accounting for 70.0 − 95.9% of TP in the intertidal surface sediments and potentially contributing substantial amounts of reactive P to the overlying water column, especially in high organic and reducing sedimentary environments.