Reactive oxygen species (ROS) are recently proposed to be involved in tumor metastasis which is a complicated processes including epithelial-mesenchymal transition (EMT), migration, invasion of the ...tumor cells and angiogenesis around the tumor lesion. ROS generation may be induced intracellularly, in either NADPH oxidase- or mitochondria-dependent manner, by growth factors and cytokines (such as TGFbeta and HGF) and tumor promoters (such as TPA) capable of triggering cell adhesion, EMT and migration. As a signaling messenger, ROS are able to oxidize the critical target molecules such as PKC and protein tyrosine phosphates (PTPs), which are relevant to tumor cell invasion. PKC contain multiple cysteine residues that can be oxidized and activated by ROS. Inactivation of multiple PTPs by ROS may relieve the tyrosine phosphorylation-dependent signaling. Two of the down-stream molecules regulated by ROS are MAPK and PAK. MAPKs cascades were established to be a major signal pathway for driving tumor cell metastasis, which are mediated by PKC, TGF-beta/Smad and integrin-mediated signaling. PAK is an effector of Rac-mediated cytoskeletal remodeling that is responsible for cell migration and angiogenesis. There are several transcriptional factors such as AP1, Ets, Smad and Snail regulating a lot of genes relevant to metastasis. AP-1 and Smad can be activated by PKC activator and TGF-beta1, respectively, in a ROS dependent manner. On the other hand, Est-1 can be upregulated by H2O2 via an antioxidant response element in the promoter. The ROS-regulated genes relevant to EMT and metastasis include E-cahedrin, integrin and MMP. Comprehensive understanding of the ROS-triggered signaling transduction, transcriptional activation and regulation of gene expressions will help strengthen the critical role of ROS in tumor progression and devising strategy for chemo-therapeutic interventions.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Low soil phosphorus (P) bioavailability causes the widespread occurrence of P‐limited terrestrial ecosystems around the globe. Exploring the factors influencing soil P bioavailability at large ...spatial scales is critical for managing these ecosystems. However, previous studies have mostly focused on abiotic factors. In this study, we explored the effects of microbial factors on soil P bioavailability of terrestrial ecosystems using a country‐scale sampling effort. Our results showed that soil microbial biomass carbon (MBC) and acid phosphatase were important predictors of soil P bioavailability of agro‐ and natural ecosystems across China although they appeared less important than total soil P. The two microbial factors had a positive effect on soil P bioavailability of both ecosystem types and were able to mediate the effects of several abiotic factors (e.g., mean annual temperature). Meanwhile, we revealed that soil phytase could affect soil P bioavailability at the country scale via ways similar to those of soil MBC and acid phosphatase, a pattern being more pronounced in agroecosystems than in natural ecosystems. Moreover, we obtained evidence for the positive effects of microbial genes encoding these enzymes on soil P bioavailability at the country scale although their effect sizes varied between the two ecosystem types. Taken together, this study demonstrated the remarkable effects of microbial factors on soil P bioavailability at a large spatial scale, highlighting the importance to consider microbial factors in managing the widespread P‐limited terrestrial ecosystems.
Understanding the factors influencing soil phosphorus (P) bioavailability at large spatial scales is critical to the development of managing strategies for P‐limited terrestrial ecosystems around the globe. However, previous studies have mostly focused on abiotic factors. Here, we explored the effects of not only abiotic factors but also microbial factors on soil P bioavailability of terrestrial ecosystems using a country‐scale sampling effort in China. We demonstrated that soil microbial biomass carbon (MBC), organic P‐mineralizing enzymes and microbial genes encoding these enzymes were important predictors of soil P bioavailability of agro‐ and natural ecosystems across China.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The paper proposes a miniaturized bandpass filter (BPF) using gallium arsenide (GaAs)‐based integrated passive device (IPD) technology. The proposed filter is evolved from traditional third order ...BPF, and it achieves a wide operation frequency band covering three 5G sub‐bands including 3.4–3.5 GHz, 3.5–3.6 GHz, and 4.8–4.9 GHz. The performance of out‐of‐band rejection is improved by introducing three transmission zeros (TZs). As known, adding cross coupling and LC resonator are the general methods to improve out‐of‐band rejection. Therefore, the first TZ at 5.85 GHz is obtained at the upper sideband by adding a capacitive coupling between the source port and resonator 2, which is a cross‐coupling mode. According to the coupling matrix, the value of the added capacitance can be calculated and optimized. Another TZ at 2.36 GHz is occurred at the left side of passband as a serial LC resonator is connected in parallel with filter near the input port. The third TZ at 7.74 GHz is generated at the upper sideband due to a serial LC resonator connected in parallel with the load terminal of the filter. The values of components in LC resonators can be calculated, too. Finally, the whole filter is optimized in full‐wave electromagnetic simulation software HFSS. The proposed filter is fabricated and measured, and the results show that it has a wide −10 dB frequency band from 3.3 GHz to 4.9 GHz and a maximum insertion loss of 2.5 dB. In addition, it has a good frequency selectivity with a rectangular coefficient of 1.67 and out‐of‐band suppression higher than 20 dB in a wide stopband. The filter adopts compact placement and has a relative miniaturized electrical size of 0.298 λ02, which is about 55% smaller than recently reported one.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A novel microwave sensor based on modified rat-race coupler for extracting complex permittivity of binary aqueous solution is proposed in this article. The proposed microwave sensing system consists ...of the modified rat-race coupler, gain/phase RF detector, and voltage-controlled oscillator (VCO). The modified rat-race coupler is constituted by three cascaded rat-race couplers, each rat-race coupler is developed from a traditional rat-race coupler, and a 50-<inline-formula> <tex-math notation="LaTeX">{\Omega } </tex-math></inline-formula> characteristic impedance transmission line port of traditional coupler is replaced by a multistepped-impedance transmission line (MSITL), which is used as sensing area. For a rat-race coupler, its sensitivity is determined by the added MSITL, and thus, the change rate between phase of reflection coefficient and concentration/real permittivity of sample for MSITL should realize the maximum value. Mathematical analysis provides a detailed explanation for what values of characteristic impedance and electrical length of each discontinuous segment of MSITL should be taken to achieve the maximum sensitivity. The relationship between concentration/real permittivity and phase of reflection coefficient can be obtained by the passive sensor, i.e., modified rat-race coupler, while the expensive vector analyzer network (VNA) is essential in measurement. In measurement, the VCO generates the RF signal source at 2.5 GHz for the microwave sensing system. Also, the gain/phase detector chip AD8302 is adopted to acquire the relation between permittivity and output dc voltage; thus, the output dc voltage can be used to predict the unknown concentration/real permittivity of sample and it can get rid of the use of VNA. For the modified rat-race coupler cascaded by three rat-race couplers, the magnitude of <inline-formula> <tex-math notation="LaTeX">{b}_{{1}} / {b}_{{4}}'' </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">{b}_{{1}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">{b}_{{4}}'' </tex-math></inline-formula> are the output powers for the ports of modified rat-race coupler) is larger than the one of single rat-race coupler, and the larger magnitude of <inline-formula> <tex-math notation="LaTeX">{b}_{{1}} / {b}_{{4}}'' </tex-math></inline-formula> denotes the larger output dc voltage for <inline-formula> <tex-math notation="LaTeX">{V}_{\text {mag}} </tex-math></inline-formula>. In measurement, the modified rat-race coupler has the maximum sensitivity of about <inline-formula> <tex-math notation="LaTeX">{{1}.{37}}^{o} / \varepsilon _{r}^{\prime} </tex-math></inline-formula>. Also, the average sensitivity for the microwave sensing system with a third-order rat-race coupler combined is about <inline-formula> <tex-math notation="LaTeX">{\text {2.{14} {mV}}} / \varepsilon _{r}^{\prime} </tex-math></inline-formula>, which is 1.93-3.28 times higher than single- and second-order rat-race coupler-based ones. All in all, the proposed microwave sensing system is an economical electronic device in the field of microfluidic detection.
The paper proposes an ultrahigh sensitivity microwave sensor for retrieving the complex permittivity of the liquid sample. The proposed sensor originally evolves from the complementary split-ring ...resonator-based sensor, which confines the electric field in the slot of the resonator. A complementary electric-LC resonator structure is applied to substitute the CSRR due to its excellent ability of concentrating the electric field. To further improve the field confinement, a meander slot is embedded in the central arm of the resonator. Then, two etched complementary split-ring resonators are added on both sides of the central meander arm of the modified complementary electric-LC resonator. A polydimethylsiloxane microfluidic channel substrate is placed on the meander arm, and a mixture of water-ethanol is injected. The variations in the resonant frequency and peak attenuation are used to retrieve the complex permittivity of the injected liquid sample. The developed sensors are fabricated and tested, and a good agreement is observed between measured data and reference values. The peak sensitivities in retrieving the relative permittivity achieve 2.5% and 2.71% with the proposed sensors, which are much higher than previously reported designs.
A differential on-chip sensor loaded with circular spiral resonators (CSRs) for charactering liquid samples is proposed in this article. The proposed on-chip sensor is working at terahertz (THz) ...frequency band, and the sensor can be fabricated by integrated passive device (IPD) technology. With comparison to square and octagonal spiral resonators, the CSR has a higher quality factor and a stronger confinement of electrical field, which are beneficial to improve the measurement sensitivity. The proposed sensor has a differential structure, and two CSRs are equally distributed on both sides of the microstrip line, and one resonator is regarded as reference, and another is utilized as test. The frequency shift and notched magnitude of transmission coefficient will be changed by loading liquid samples with different complex permittivities; thus, the relevant mathematical relationship between S-parameters and permittivity can be established. However, as the cost of fabricating on-chip sensor by IPD technology is too expensive, printed circuit board (PCB) technology is used to fabricate the proposed sensor and to verify the feasibility of the sensor. It should be noted that the on-chip sensor operates at THz band, while the PCB-based sensor operates at microwave (MW) band. The experiment shows that the proposed CSRs-based MW sensor has a high sensitivity of about 0.28%. When the real permittivity changes by one unit, the resonant frequency shifts for the microwave sensor and THz sensor are about 0.445 and 1.45 GHz, i.e., <inline-formula> <tex-math notation="LaTeX">\text {0.{445}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">1.45 {\text {GHz}/}\varepsilon _{r}^{\prime} </tex-math></inline-formula>, respectively. Obviously, the on-chip THz sensor has a higher resolution than the microwave sensor. All in all, the proposed differential microwave CSR-based sensor is a good candidate in the field of microfluidic measurement.
Inventory is the basis of business activities; inventory management helps industries keep their inventories stocked with reasonable quantities, which ensures consumers demand while minimizing storage ...costs. The traditional manual inventory management has low efficiency and a high labor cost. In this paper, we used improved YOLOv3 to detect the cups stored on the warehouse shelves and counted their numbers to realize automated inventory management. The warehouse images are collected by the camera and transmitted to the industrial computer, which runs the YOLOv3 network. There are three feature maps in YOLOv3, the two smaller feature maps and the structure behind them are removed, and the k-means algorithm is used to optimize the default anchor size. Moreover, the detection range is limited to a specified area. Experiments show that, by eliminating those two feature maps, the network parameter is reduced from 235 MB to 212 MB, and detection FPS is improved from 48.15 to 54.88 while mAP is improved from 95.65% to 96.65% on our test dataset. The new anchors obtained by the k-means algorithm further improve the mAP to 96.82%. With those improvements, the average error rate of detection is reduced to 1.61%. Restricted detection areas eliminate irrelevant items to ensure the high accuracy of the detection result. The accurately counted number of cups and its change provide significant data for inventory management.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A microwave sensor system based on the oscillating technique for retrieving complex permittivity of liquid samples is proposed in this article. In design of the proposed sensing system, it mainly ...includes two parts, i.e., reflective RF oscillator and RF link circuits. In a reflective RF oscillator, the passive resonance unit is regarded as a load network. The sum of the input resistance of the transistor and the output resistance of the load network should be negative, and the sum of reactance should be equal to 0, and these two requirements are the oscillation conditions. If a frequency satisfies the oscillation conditions, the oscillator will output the RF signal at this frequency. When a liquid sample with different complex permittivities is loaded, the oscillator will generate different oscillation frequencies. By the RF link circuits, different oscillation frequencies can be converted into different output dc voltages. In the system, the RF link consists of a power divider, low noise amplifier (LNA), mixer, phase shifter, hybrid coupler, and low-pass filter (LPF). The structure of the passive resonance unit is simple, it is constituted by a microstrip line and a split-ring resonator (SRR), and the microstrip line is coincident with one side of SRR. The proposed passive resonant unit can produce two resonant modes, i.e., odd and even modes. The interdigital electrode (IDE) is inserted at the open area to improve the density of the electrical field. The reflective RF oscillator combined with an RF link can abandon the use of vector network analyzer (VNA), and lower the cost. The two-way output dc voltages (<inline-formula> <tex-math notation="LaTeX">{V}_{I} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">{V}_{Q} </tex-math></inline-formula>) are utilized to retrieve the complex permittivity of liquid samples. In measurement, the changed range of <inline-formula> <tex-math notation="LaTeX"> {V}_{I} / {V}_{Q} </tex-math></inline-formula> is about 13.59/12.9 mV for the water concentration changing from 0% to 100%, and the consumed volume of the liquid sample is <inline-formula> <tex-math notation="LaTeX"> {0.72}~ \mu \text { L} </tex-math></inline-formula>. In measurement, the error of retrieving <inline-formula> <tex-math notation="LaTeX"> \varepsilon _{r}^{\prime } / \varepsilon _{r}^{\prime } </tex-math></inline-formula> is −9.1%/−7.7%. In the future, each circuit module of the proposed microwave sensing system can be integrated into a single board to form a portable detection device.
Elton's biotic resistance hypothesis, which posits that diverse communities should be more resistant to biological invasions, has received considerable experimental support. However, it remains ...unclear whether such a negative diversity–invasibility relationship would persist under anthropogenic environmental change. By using the common ragweed (Ambrosia artemisiifolia) as a model invader, our 4‐year grassland experiment demonstrated consistently negative relationships between resident species diversity and community invasibility, irrespective of nitrogen addition, a result further supported by a meta‐analysis. Importantly, our experiment showed that plant diversity consistently resisted invasion simultaneously through increased resident biomass, increased trait dissimilarity among residents, and increased community‐weighted means of resource‐conservative traits that strongly resist invasion, pointing to the importance of both trait complementarity and sampling effects for invasion resistance even under resource enrichment. Our study provides unique evidence that considering species’ functional traits can help further our understanding of biotic resistance to biological invasions in a changing environment.
Whether biodiversity would consistently resist invasion under global change scenarios is poorly understood. Our four‐year grassland experiment showed that plant diversity was a consistent barrier to common ragweed invasion irrespective of nitrogen addition, and that plant diversity resisted invasion simultaneously through increases in the biomass, functional diversity, and dominance of conservative traits, of the resident communities.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
