Search

Designing a monochromatic spatially-structured light field that recovers the pre-specified profile of optical force (OF) exerted on a particle is an inverse problem. It usually requires high dimensional optimization and involves lengthy calculations, thus remaining little studied despite decades of research on OF. We report here the first attempt to attack this inverse design problem. The modus operandi relies on the back-propagation algorithm, which is facilitated by the currently available machine learning framework, and, in particular, by an exact and efficient expression of OF that shows only polynomial and trigonometric functional dependence on the engineered parameters governing the structured light field. Two illustrative examples are presented in which the inversely designed structured light fields reproduce, respectively, a predefined spatial pattern of OF and a negative longitudinal OF in a transversely trapping area.

In this paper, we aim to minimize the total power of all the Internet of Things devices (IoTDs) by jointly optimizing user association, computation capacity, transmit power, and the location of unmanned aerial vehicles (UAVs) in an UAV-assisted cloud radio access network (C-RAN). In order to solve this non-convex problem, we propose an effective algorithm by solving four subproblems iteratively. For the user association and the computation capacity subproblems, the non-convex constraints are relaxed and the optimal solutions are obtained. For the transmit power control and the location planning subproblems, successive convex approximation (SCA) technique is used to transform the non-convex constraints into convex ones. Moreover, to obtain the suboptimal solutions, slack variables are also introduced to deal with the feasibility-check problems. The simulation results demonstrate that the proposed algorithm can greatly reduce the total power consumption of IoTDs.

Acyl-CoA-binding proteins (ACBPs) are important for the transport of acyl groups for macromolecular biosynthesis involved in plant growth, development, and diverse stress (e.g., cold, drought, salinity, and heavy metals) responses. Here, we report the phylogeny and characteristics of the ACBP family in the woody plant Populus trichocarpa. Eight genes encoding ACBP proteins were identified, and they are distributed on eight chromosomes in P. trichocarpa. These PtACBP genes were divided into four subgroups according to gene structure, conserved motifs and phylogenetic relationship. Promoter analysis revealed that cis-elements were related to stress response, phytohormone response, and physical and reproductive growth regulation. Expression levels of PtACBP genes varied among different organs, with the highest expression in leaves and the lowest in stems. Quantitative real-time PCR (qRT-PCR) analysis showed that under salinity-alkali stresses (i.e., 200 mM NaCl, 75 mM Na2CO3, and 100 mM NaHCO3), four (PtACBP1, PtACBP3, PtACBP4 and PtACBP8) of eight PtACBP genes were significantly induced in roots and leaves. These data provide a comprehensive analysis of the ACBPs family in P. trichocarpa, which could be useful for gene function analyses.

Coastlines with different morphologies form boundaries between the land and ocean, and play a vital role in tourism, integrated coastal zone management, and marine engineering. Therefore, determining how to extract the coastline from satellite images quickly, accurately, and intelligently without manual intervention has become a hot topic. However, the instantaneous waterline extracted directly from the image must be corrected to the coastline using the tide survey station data. This process is challenging due to the scarcity of tide stations. Therefore, an improved instantaneous waterline extraction method was proposed in this paper with an integrated Otsu threshold method, a region-growing algorithm, Canny edge detection, and a morphology operator. Based on SAR feature extraction and screening, the multi-scale segmentation method and KNN classification algorithms were used to achieve object-oriented automatic classification. According to different types of ground features, the correction criteria were presented and used in correcting the instantaneous waterline in biological coasts and undeveloped silty coasts. As a result, the accurate extraction of the coastline was accomplished in the area of the Yellow River Delta. The coastline was compared with that extracted from the GF-1 optical image. The result shows that the deviation degree was less than the field distance represented by three pixels.

This paper investigates the polarization persistence of linear polarization and circular polarization in foggy environments from ultraviolet (UV) to near-infrared (NIR). Using polarization tracking Monte Carlo simulation for varying particle size, wavelength, refractive index, and detection distance, it is shown that linear polarization and circular polarization exhibit different persistence performance. For wet haze of 0.6 μm mean diameter particles, right-handed circular polarization shows better persistence than parallel polarization at wavelengths of 0.36, 0.543 and 1.0 μm. But parallel polarization shows better persistence at wavelengths of 1.55, 2.1 and 2.4 μm. For wet haze of 1.0 μm mean diameter particles, right-handed circular polarization shows better persistence at wavelengths of 0.36, 0.543, 1.0 and 1.55 μm. But parallel polarization shows better persistence at wavelengths of 2.1 and 2.4 μm. For wet haze of 2.0 μm particles and radiation fog and advection fog, right-handed circular polarization shows better persistence at all simulated wavelengths. In short, right-handed circular polarization persists better than parallel polarization in most scenarios, however, with increasing wavelength and decreasing particle size, parallel polarization gradually persists better than right-handed circular polarization. Finally, anisotropy factor for various particle models is used to map the propagation law of right-handed circular polarization and parallel polarization.

Inorganic phosphate (Pi) deficiency is a main limiting factor on crops growth and to select low-Pi tolerant breeding lines is very significant for crop breeding. Here, two contrasting maize (Zea mays L.) breeding lines showed different physiological response to Pi deficiency. The low-Pi tolerant QXN233 maintained normal growth, including high fresh weight, green leaves, strong shoots, and numerous roots relative to that of the sensitive MH05-4, mainly due to QXN233’ high Pi content in shoots under Pi deficiency. Importantly, some Pi-responsive genes were detected, and among them, Pi transporters ZmPHT1;1 and ZmPHT1;9 as well as phytase gene Zmphytase 2 were expressed increasingly in QXN233 compared to MH05-4 under Pi deprivation or Pi resupply. Moreover, QXN233 had higher proline content, soluble sugar content, and SOD activity than MH05-4, related with its tolerance. Taken together, this study enriches the understanding of the mechanism of maize responding to Pi deficiency.

Background Despite numerous chimeric antigen receptor T‐cell (CAR‐T) trials conducted in China, no CAR‐T has been registered in the country. Furthermore, China law and regulations restrict the export of patient material for CAR‐T manufacture abroad. Relma‐cel (JWCAR029), an anti‐CD19 product produced with a commercial‐ready process in China, was evaluated in the first prospective, single‐arm, multicenter, pivotal study of CAR‐T therapy conducted under Chinese IND to support an NMPA‐accepted BLA submission in relapsed/refractory (r/r) LBCL (NCT04089215). Methods Patients were randomized to receive either 100 × 106 (low dose, n = 27) or 150 × 106 (high dose, n = 32) CAR+ T‐cells as a single infusion following lymphodepleting chemotherapy (fludarabine 25 mg/m2 and cyclophosphamide 250 mg/m2 daily × 3), and then, monitored for efficacy and safety outcomes and pharmacokinetics. The primary endpoint was ORR at 3 months, as assessed by the investigators. Secondary endpoints included DOR, PFS, OS, and adverse event frequency/severity and cell expansion kinetics. Results As of the data cutoff on 17 June 2020, 68 patients were enrolled, and 59 were treated. Among the 58 efficacy‐evaluable patients, the primary endpoint of 3 month ORR was 60.3% (95% CI, 46.6–73.0), excluding the null hypothesis rate of 20%. Any grade and severe grade CRS occurred in 47.5% and 5.1%, respectively, and any grade and severe grade neurotoxicity events occurred in 20.3% and 5.1%. Conclusions Relma‐cel met the primary endpoint analysis and demonstrated a high rate of durable responses and low rate of CAR‐T‐associated toxicities in patients with r/r LBCL in a multicenter trial supporting regulatory submission in China., The RELIANCE Trial provided the first demonstration of licensure‐quality CAR‐T manufacturing and clinical trial data generation in r/r patients originating in China. The results with relma‐cel demonstrate similar preliminary response rates and PK profiles while providing the potential for an improved toxicity profile in heavily‐pre‐treated patients with r/r DLBCL having poor risk features relative to other CD19‐specific CAR‐Ts approved in the US and EU.

We demonstrate that, in a simple linearly-polarized plane wave, the optical pulling forces on nanoparticle clusters with gain can be induced by the Fano-like resonance. The numerical results based on the full-wave calculation show that the optical pulling forces can be attributed to the recoil forces for the nanoparticle clusters composed of dipolar nanoparticles with three different configurations. Interestingly, the recoil forces giving rise to optical pulling forces are exactly dominated by the coupling term between the electric and magnetic dipoles excited in the nanoparticle clusters, while other higher-order terms have a negligible contribution. In addition, the optical pulling force can be tailored by modulating the Fano-like resonance via either the particle size or the gain magnitude, offering an alternative freedom degree for optical manipulations of particle clusters.

Based on the generalized Lorenz-Mie method and Maxwell stress tensor theory, we demonstrate that a lateral optical force (OF) can be induced on a spherical particle along the translationally invariant direction of incident optical fields formed by multiple circularly polarized plane waves. It is analytically shown that the lateral OF depends on two quantities associated with the illuminating field, regardless of the particle properties such as material composition and particle size. Interestingly, for some special cases like two- or three-wave interference field, the lateral OF is rigorously proportional to the Poynting vector. As examples, the numerical results for the interference field composed of two or three circular polarized plane waves show that the spatial distribution pattern of the lateral OF is always determined by Poynting vectors of the illuminating field itself, while the particle size and material affect solely the magnitude but not the spatial profile of the lateral OF. In addition, the magnitude of the lateral OF is comparable to other components of the OF. The lateral OF is traced to the scattering force due to the interference between multipoles excited on the particle. These findings may enrich the concept of the lateral OF and also add an additional implement to the optical manipulation toolbox.

The interaction mechanisms of nimodipine with pepsin, trypsin, α-chymotrypsin, lysozyme and human serum albumin were investigated by multispectral and molecular docking methods. Vitamin C and naringin were the main active components of grapefruit juice, and nimodipine was the typical drug that interacts with this juice. Fluorescence spectroscopy was used to study the interaction of nimodipine with five proteinases (pepsin, trypsin, α-chymotrypsin, lysozyme and human serum albumin) and the effects of vitamin C and naringin on these interactions. The fluorescence quenching results showed that nimodipine can quench the intrinsic fluorescence of these five proteinases by a static quenching procedure. Nimodipine binds to pepsin and α-chymotrypsin, through hydrogen bonding and van der Waals forces, whereas it binds to trypsin, lysozyme and human serum albumin mainly by hydrophobic interactions. The microenvironment of the five proteinases changed. The probability of nonradiative energy transfer between the five proteinases and nimodipine was high. Both vitamin C and naringin reduced the binding constant of nimodipine to the four proteinases (except α-chymotrypsin) and might increase the concentration of free nimodipine. Thus, vitamin C or naringin in fruits or foods could increase the blood concentration of free nimodipine and perhaps a reduction in nimodipine dose was needed.

Based on the multipole expansion theory, we show that a transverse optical torque acting on a dipolar plasmonic spherical nanoparticle can be anomalously enhanced in two plane waves with linear polarization. Compared with a homogeneous Au nanoparticle, the transverse optical torque acting on an Au–Ag core–shell nanoparticle with an ultra-thin shell thickness can be dramatically enhanced by more than two orders of magnitude. Such enhanced transverse optical torque is dominated by the interaction between the incident optical field and the electric quadrupole excited in the dipolar core–shell nanoparticle. It is thus noted that the torque expression based on the dipole approximation usually used for dipolar particles is not available even in our dipolar case. These findings deepen the physical understanding of the optical torque (OT) and may have applications in optically driven rotation of plasmonic microparticles.

We rigorously calculate the conservative gradient force (GF) and the non-conservative scattering force (SF) associated with the optical tweezers (the single beam optical trap). A wide range of parameters are considered, with particle size ranging from the Rayleigh to Mie regime (radius ∼3 µm), dielectric constant ranging from metallic (large and negative) to high dielectrics (large and positive), numerical aperture (NA) ranging from 0.5 to 1.33, and different polarizations. The trap depth associated with GF can reach 123 and 168 kBT per mW for a 0.5 µm-radius polystyrene particle illuminated by a 1064 nm Gaussian beam with NA = 0.9 and 1.3, respectively. This indicates that unless at a low beam power or with a small NA, the Brownian fluctuations do not play a role in the stability. The transverse GF orthogonal to beam propagation always dominates over the transverse SF. While the longitudinal SF can be larger than the longitudinal GF when the scattering is strong, the NA is small, or when absorption is present, optical trapping under these conditions is difficult. Generally speaking, absorption reduces GF and enhances SF, while increasing a dielectric constant enhances GF slightly but boosts SF significantly owing to stronger scattering. These results verify previous experimental observations and explain why optical tweezers are so robust across such a wide range of conditions. Our quantitative calculations will also provide a guide to future studies.

This paper presents an investigation of the transmitting power consumption of a base station (BS) in a simultaneous wireless information and power transfer (SWIPT) system enhanced by a reconfigurable intelligent surface (RIS). The aim is to optimize the total transmitting power consumption when sending information signals and energy from the BS to ground sensors. To this end, the transmitting power consumption of the BS is optimized by satisfying the sensor’s minimum signal-to-interference-plus-noise ratio (SINR), the phase shift constraints of the RIS, and each sensor’s power-splitting (PS) ratio. In order to decouple the optimization variables, we use the technique of block coordinate descent (BCD) to transform the total problem into subproblems. In the second subproblem, the unit modulus constraints are approximated using the successive convex approximation (SCA) method, allowing the optimal solutions to be obtained by solving subproblems in an iterative manner. Our numerical simulation results show that transmitting power consumption can be significantly decreased by adding RIS to an SPWIT system, even in nonlinear harvest models of real application scenarios.

A MATLAB function GCforce is presented for the calculation of gradient and scattering parts of optical force (OF). The decomposition of OF into the gradient and scattering parts, or, equivalently, the conservative and nonconservative components, is of great importance to the physical understanding of optical micromanipulation. In this paper, we propose a formulation to decompose the OF acting on a spherical particle immersed in an arbitrary monochromatic optical field, based on the generalized Lorenz–Mietheory and the Cartesian multipole expansion approach. The expressions for the gradient and scattering forces are given explicitly in terms of the partial wave expansion coefficients of the optical field shining on the particle and the Mie coefficients of the particle. A MATLAB function GCforce.m is also presented for the calculation. The explicit and rigorous decomposition of the OF into conservative and nonconservative forces sheds light on the understanding of light–matter interaction as well as contributes significantly to the designing of optical fields to achieve various optical micromanipulation. Program summary Program Title: GCforce Program Files doi: http://dx.doi.org/10.17632/9ytk7bv3md.1 Licensing provisions: GPLv3 Programming language: MATLAB Nature of problem: Decomposition of optical force acting on an isotropic spherical particle of size comparable to optical wave length into conservative (gradient) and nonconservative (scattering) components. Solution method: By deriving the explicit expressions for computing the optical gradient force and scattering force exerting on the particle in terms of the partial wave expansion coefficients of the incident monochromatic optical field.

Phytopathogenic bacteria cause severe economic losses in agricultural production worldwide. The spread rates, severity, and emerging plant bacterial diseases have become serious threat to the sustainability of food sources and the fruit industry. Detection and diagnosis of plant diseases are imperative in order to manage plant diseases in field conditions, greenhouses, and food storage conditions as well as to maximize agricultural productivity and sustainability. To date, various techniques including, serological, observation-based, and molecular methods have been employed for plant disease detection. These methods are sensitive and specific for genetic identification of bacteria. However, these methods are specific for genetic identification of bacteria. Currently, the innovative biosensor-based disease detection technique is an attractive and promising alternative. A biosensor system involves biological recognition and transducer active receptors based on sensors used in plant-bacteria diagnosis. This system has been broadly used for the rapid diagnosis of plant bacterial pathogens. In the present review, we have discussed the conventional methods of bacterial-disease detection, however, the present review mainly focuses on the applications of different biosensor-based techniques along with point-of-care (POC), robotics, and cell phone-based systems. In addition, we have also discussed the challenges and limitations of these techniques.

The mechanism of phosphate (Pi)-mediated salt tolerance in maize is poorly understood. In this study, the effects of Pi (H2PO4−) on the salt tolerance of two contrasting genotypes was investigated in a pot experiment. We discovered that the application of 3 mM Pi could alleviate salt injury caused by 200 mM NaCl. High amounts of compatible solutes and low amounts of reactive oxygen species (ROS) were also observed under Pi application. Consistent with the increased tolerance, the total number of roots and the growth of shoots increased to relieve salt stress. This phenomenon could be associated with the observed increased expression of nitrate transporters. Furthermore, the seedlings presented a negative relationship between sodium (Na+) and Pi (low Na+ content and high Pi content), which is related to the genes ZmNHX1, ZmPHT1;8, and ZmPHT1;9, indicating that the exclusion of Na+ was promoted by high Pi uptake. However, high Na+ and low potassium (K+) efflux were detected in the roots, and these were positively correlated with two K+ transporters. These observations indicate that Na+ exclusion was directly induced by high K+ retention rather than Pi absorption. We conclude that maize salt tolerance increased in response to Pi application by promoting Na+ exclusion.

Eupatorium fortunei Turcz. is a widely used Chinese herbal medicine in China. In this study, a gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) method was developed and validated to simultaneously determine the contents of p-cymene, thymol, neryl acetate, and β-caryophyllene in roots, stems, and leaves of Eupatorium fortunei Turcz. harvested at different growth periods. All four constituents could be detected in leaves, three could be detected in stems except β-caryophyllene, and only thymol could be detected in roots. The order of the total contents of four constituents in different parts was leaves > stems > roots. It indicated that the leaves could be the proper medicinal parts of Eupatorium fortunei Turcz. The content of four constituents in leaves varied a lot among different growth periods and showed an M-shaped change trend with the growth of Eupatorium fortunei Turcz. The four constituents accumulated to the highest values in early July followed by mid-September. Accordingly, the best harvest time of Eupatorium fortunei Turcz. is early July and mid-September.

The working mechanism of optical tweezers is generally believed to be the gradient force arising from the light intensity inhomogeneity of an incident optical field. Here we demonstrate a somewhat counterintuitive phenomenon---optical trapping of chiral particles relying on the gradient force emerging in an optical field with homogeneous light intensity. This type of gradient force is shown to survive even in the Rayleigh limit, where the particle size is far smaller than the illuminating wavelength. By deriving a rigorous analytical expression for the optical force exerted on a chiral particle, the origin of such a gradient force is traced to the gradient of the magnetoelectric energy density, irrespective of the particle size. Besides enriching our understanding of the light-matter interaction, this gradient force is found to have magnitude comparable to the conventional intensity gradient-induced gradient force and to switch its direction for particles with opposite chiralities, rendering it applicable to particle chirality discrimination and identification.

Based on the Maxwell stress tensor method and the full wave simulations, we show that a lateral optical force (LOF) can be induced on a pair of spherical nanoparticles with different chiral combinations under the illumination of plane waves with the linear polarization either parallel or normal to the axis of the two nanospheres. It is demonstrated that the LOF can appear on each particle in the direction perpendicular to the particles' axis and the light propagation when either one or two particles have the chirality. Such an LOF can be tailored by both the magnitude and handedness of the particle chirality as well as the incident linear polarizations. Using the analytical expression of optical forces based on the dipole approximation, the physical origin of the LOF can be traced to many channels, including the gradient force, the radiation force, the curl force, and the spin force due to the inter-particle interaction mediated by the light. Our results might find applications in chiral discrimination such as chiral molecular and biological cells.

Based on the concepts of conservative and non-conservative optical forces (COF and NCOF), we analyze the physical mechanism of longitudinal chirality sorting along the direction of light propagation in some simple optical fields. It is demonstrated, both numerically and analytically for particle of arbitrary size, that the sorting relies solely on the NCOF, which switches its direction when particle chirality is reversed. For particles larger than half of the optical wavelength λ , the NCOF far surpasses its counterpart COF, enabling the longitudinal chirality sorting. When the particle is much smaller than λ , however, the COF outweighs the NCOF, destroying the sorting mechanism. A scenario is thus proposed that totally eliminates the COF while leaving the sorting NCOF unchanged, extending the applicability of longitudinal chirality sorting to small particles.