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The accurate, simple and sensitive detection of bacterial infections at the early stage is highly valuable in preventing the spread of disease. Recently, CRISPR-Cas12a enzyme-derived nucleic acid detection methods have emerged along with the discovery of the indiscriminate single-stranded DNA (ssDNA) cleavage activity of Cas12a. These nucleic acid detection methods are made effective and sensitive by combining them with isothermal amplification technologies. However, most of the proposed CRISPR-Cas12a strategies involve Cas-crRNA complexes in the preassembled mode, which result in inevitable nonspecific background signals. Besides, the signal ssDNA used in these strategies needs tedious pre-labeling of the signal molecules. Herein, a post-assembly CRISPR-Cas12a method has been proposed based on target-induced transcription amplification and real-time crRNA generation for bacterial 16S rDNA biosensing. This strategy is label-free through the combination of microchip electrophoresis (MCE) detection. In addition, this method eliminates the need for a protospacer adjacent motif (PAM) on the target sequences, and has the potential to be an effective and simple method for nucleic acid detection and infectious disease diagnosis.

Current strand displacement amplification (SDA)-based nucleic acid sensing methods generally rely on a ssDNA template that involves complementary bases to the endonuclease recognition sequence, which has the limitation of detecting only short nucleic acids. Herein, a new SDA method in which the defective T junction structure is first used to support SDA (dT-SDA) was proposed and applied in longer DNA detection. In dT-SDA, an auxiliary probe and a primer were designed to specifically identify the target gene, following the formation of a stable defective T junction structure through proximity hybridization, and the formation of defective T junctions could further trigger cascade SDA cycling to produce numerous ssDNA products. The quantity of these ssDNA products was detected through microchip electrophoresis (MCE) and could be transformed to the concentration of the target gene. Moreover, the applicability of this developed strategy in detecting long genomic DNA was verified by detecting bacterial 16S rDNA. This proposed dT-SDA strategy consumes less time and has satisfactory sensitivity, which has great potential for effective bacterial screening and infection diagnosis.

Mucin 1 (MUC1) is usually overexpressed in a variety of malignant tumors, and quantitative analysis of MUC1 plays an important role in the early diagnosis of cancer. In this work, a highly sensitive MUC1 assay was developed by integrating microchip electrophoresis (MCE) with target recycling amplification (TRA) and strand displacement amplification (SDA). Specifically, the presence of MUC1 can trigger the exposure of the designed hairpin probe (HP) to initiate SDA and an amplified amount of ssDNA is produced finally. The amount of these ssDNA can be detected by MCE, then the concentration of MUC1 can be obtained through the correlation between MUC1 concentration and ssDNA concentration. The experimental results show that the MCE signal had a good linear relationship with MUC1 concentration in the range of 1.0 pg/mL - 1.0 × 10

Near-infrared (NIR, 700–1700 nm) bioimaging has gained considerable attention in recent years owing to its high imaging resolution and increasing penetration depth of tissues. NIR emissive lanthanide(III) complexes have emerged as alluring candidates for the design of NIR molecular probes in clinical imaging and diagnosis because of their desirable temporal–spatial resolution, negligible photobleaching effect, long lifetime and low biotoxicity. In this mini-review, we summarize our efforts in the molecular design of NIR luminescent lanthanide porphyrinoids and their biological applications in bioimaging and further clinical diagnosis and treatment. Remarkably, β-fluorinated porphyrin Yb3+ probes exhibit high luminescence (5–13% quantum yields in H2O), long decay lifetimes (>100 μs) and enable in vivo fluorescence intensity imaging and time-resolved fluorescence lifetime imaging (FLIM). Finally, the main concerns and challenges for NIR emissive Ln biolabels such as the diversity of the NIR Ln3+ optical toolbox and their biocompatibility and targeting capability in biological media are discussed so as to facilitate the long-term development of lanthanide chemical biology.

Purpose The objective of this study was to evaluate the safety and efficacy of immune checkpoint inhibitors applied in the small cell lung cancer patients with brain metastases. Methods We retrospectively reviewed the records of small cell lung cancer patients with brain metastases treated with chemotherapy and radiotherapy for brain metastases with or without immune checkpoint inhibitors at our institution from January 2019 to January 2021. Patients were divided into two groups. In Group A, patients received chemotherapy and radiotherapy. In Group B, patients received chemotherapy, radiotherapy and at least four cycles of immunotherapy. Overall survival and intracranial progression-free survival were assessed using Kaplan-Meier estimates and Cox regression models. Results A total of 295 patients were enrolled in our study. By the end of the study (March 12, 2021), the median overall survival was 28.1 months among 64 patients in Group B, and 13.2months among 231 patients in Group A respectively (hazards ratio [HR] 0.450, 95% confidence interval [CI], 0.263–0.769, P = 0.004). Both the univariate analysis and multivariate analysis suggested two factors were significantly correlated with overall survival, including immunotherapy, presence of extracranial metastases. The median intracranial progression-free survival was 7.63months in Group A, 10.47 months in Group B (HR = 0.716, 95% confidence interval [CI], 0.326–0.973, P = 0.040). The intracranial objective response rate and intracranial disease control rate was similar between them. Conclusion Immunotherapy plus chemotherapy and radiotherapy for brain metastases showed promising efficacy for small cell lung cancer patients with brain metastases.

We theoretically and experimentally investigate the laser-detected magnetic resonance spectra dressed by a radio-frequency magnetic field in F g = 4 of D1 line of cesium atoms. The analytical expression of the transmission spectrum for magnetic resonance dressed by a radio-frequency magnetic field is derived and has substantial agreement with the transmission spectra observed in the experiment. The theoretical prediction of the ratio of the amplitudes of the two sidebands with the detuning is basically consistent with the experimental data, which confirms the validity of the analytical expression. The separation between the two sidebands under resonance shows a highly linear proportion to the amplitude of the dressing field, which may provide a useful scheme for the measurement of radio-frequency magnetic field and magnetic imaging.

We have theoretically and experimentally investigated the laser-detected magnetic resonance induced by radio-frequency two-photon processes in ${F}_{g}=4$ of ${D}_{1}$ line of cesium atoms. The effective Hamiltonian for the interaction between the two radio-frequency magnetic fields and sublevels at the ground state of ${F}_{g}=4$ is derived. By appropriately selecting the frequencies of the two radio-frequency fields, the Raman two-photon process and the cascade two-photon process can occur, which induce the magnetic resonance detected through laser transmission spectra. The theoretical calculation results fit well with the experimental data. Our results maybe apply for measuring the high bandwidth radio-frequency magnetic fields in space and studying the magnetic-induction tomography.

The existing photodetectors at home and abroad are generally lack adjustable gain and bandwidth, which makes it difficult to optimize various parameters. A low noise differential photodetector is designed. Its main gain is adjustable in the range of 10k-l0M, bandwidth is adjustable in the range of DC-3Mhz, and compensation amplification gain is adjustable in the range of 1-10. The equivalent noise model of PIN (positive-intrinsic-negative) photodiode and its amplifier circuit is analyzed. The optimal signal-to-noise ratio is 47dB and the minimum resolvable optical power is 1nW. The output voltage amplitude is linear with the input light intensity. When the signal frequency is within 3MHz, the signal can be detected without distortion. While meeting the performance requirements, the adjustable parameters are easy to explore the influence of gain, bandwidth and other factors on the experimental results, which is flexible and easy to be applied and promoted in precision spectroscopy and quantum optics experiments.

Frequency-resolved photon statistics of resonance fluorescence generated from a two-level system driven by a strong laser field and a weak laser field with equal frequencies are studied. The frequency resolution of fluorescent radiation is described by quantum filtering dynamics, which is simulated theoretically by two single-mode quantum optical cavities with tunable frequencies to scan the incident fluorescent radiation. By calculating the two-photon intensity–intensity correlation functions in terms of the cavity modes, we demonstrate that two-color strong correlations of resonance fluorescence can be generated not only between the opposite sidebands, but also between the central band and one of the sidebands: although both sidebands are broadened due to the perturbation of the weak laser field on the strong-field dressed atom. We emphasize that these properties are in contrast to the conventional case of the standard single-atom Mollow triplet. Moreover, if the resonance frequencies of the two filtering cavities are tuned appropriately, broadband two-color strong correlations are predicted, and the physical origin is revealed from the perspective of quantum interference of photon emission dynamics. This can be considered as a feasible scheme for the design of broadband non-classical light sources, and may be beneficial to the quantum precise detection of atomic and molecular dynamics via quantum optical spectroscopy.

Grape seed proanthocyanidins (GSP) are known as condensed tannins and have been used as an anti-oxidant in various neurodegenerative diseases. In our study, GSP was used as a daily dietary supplement and the neuroprotective effects were evaluated on the retinal ganglion cells (RGCs) in the retinal tissues in glaucomatous DBA/2D (D2) mice. D2 mice and age-matched non-glaucomatous DBA/2J-Gpnmb+ (D2-Gpnmb+) mice were fed with GSP or a control diet for up to 6 months. The intraocular pressure (IOP), RGC survival, glial fibrillary acidic protein (GFAP), the levels of apoptotic proteins, and the expression of oxidative stress markers in retinal tissues were determined. In our study, the neuroprotective effects of GSP on retinal tissues were confirmed, as evidenced by (a) GSP inhibited the IOP elevation in D2 mice; (b) GSP enhanced RGC survival and mediated the apoptotic protein expression; (c) GSP suppressed GFAP expression; and (d) the oxidative stress and the levels of mitochondrial reactive oxygen species were regulated by GSP. Our findings indicate that GSP has promising potential to preserve retinal tissue functions via regulating oxidative stress and mitochondrial functions.

We present a theoretical study of double-resonance alignment magnetometers using linearly polarized light, in which the effect of atomic high-order multipole moments is considered. Starting from the effective master equation of our system obtained by eliminating the excited state adiabatically, we derive the full evolution equations of the atomic multipole moments. The analytic solutions of resonance signals involving the four-order multipole moments effect are obtained by using the perturbation approach. We present that the four-order multipole moments effect is negligible in the weak laser field, and the results reduce to that obtained by a three-step approach. However, the role of four-order multipole moments coupled by two-order tensor moments is more significant with the increasing Rabi frequency of light, which cannot be ignored. Meanwhile, the analytic expressions of relaxation processes are also studied, which are a linear combination of the laser-induced equivalent relaxation rate Γ L and the spin-exchange collision rate Γ g . The expected domain of validity of the three-step approach on light power is roughly given by Γ L < 1 2 Γ g . In addition, the steady-state results of resonance signals are presented in a strong radio-frequency magnetic field; in that case, the physical mechanism of the splitting of resonance signals is discussed. These results are valid for arbitrary light power and for an arbitrarily oriented static magnetic field.

We demonstrate a simple technique to lock the frequency of a laser to an atomic transition with a new technique of subnatural linewidth spectroscopy. The coupled rubidium system exhibits an enhanced absorption spectrum of the probe beam with a subnatural linewidth. Compared with other techniques with an additional laser, our scheme only utilizes a single laser, which will be locked. The observed spectroscopic linewidth is down to about 3.5 MHz. The laser frequency fluctuation is about 226 kHz after locking on. The demonstrated scheme offers a convenient and low-cost technique for laser frequency stabilization and related precision measurements.

A DC current sensor based on an optically pumped atomic magnetometer is proposed. It has a high linearity in a wide operation range, since the magnetometer measures the absolute magnitude of the magnetic field produced by the current to be measured. The current sensor exhibits a high accuracy with a non-moment solenoid and magnetic shielding to suppress the influence from the environment. The absolute error of the measured current is below 0.08 mA when the range is from 7.5 mA to 750 mA. The relative error is 5.54 × 10−5 at 750 mA.

Twenty eight male patients with non-pathological fracture neck of femur (FNOF), age range 61-89 years, mean age 74.4 years, presented for surgery for fracture neck of femur to Merlin Park Regional Hospital, Galway Ireland and 28 age and sex matched control patients, age range 60-85 years, mean age 72.4 years who were admitted to the medical ward for various complaints including chest pain, gastroenteritis, and upper respiratory tract infections were included in the study. Following a formal written consent blood were collected for CBC, CMP, and total and free testosterone levels, LH, Estradiol, total 25(OH)D and 1,25(OH)2D, and PTH levels pre-operatively. Bone mineral density was done within 7 days of the incident fracture on the patients and the control groups after enrollment. The study is approved by the local IRB.

Nanocomposites of silica, single-wall carbon nanotubes, and graphite nanoplatelets in an epoxy matrix were prepared using a novel single-step room temperature ionic liquid (RTIL) preparation strategy. Silica nanocomposites showed improved fracture toughness and modulus, carbon nanotube composites showed electrical network percolation at 8.6 × 10 −5 volume fraction, and graphite nanoplatelets composites showed electrical percolation at 1.7 × 10 −2 volume fraction. These results were compared with literature results for nanocomposites made with volatile solvents, demonstrating the viability of the RTIL nanocomposite preparation strategy.

In China, Grape bagging was done by mostly manual work. In order to improve the intelligence level of grape bagging and reduce the amount of human labor, a robot system for grape bagging was developed. The hardware structure of robot system was designed based on cylindrical coordinate. One kind of grape extraction algorithm based on 2G-R-B was developed. And the control system of grape bagging robot was completed. The robot could realize starting the machine automatically. The performance test of grape bagging robot indicated that the success rate for bagging grape was 85%, and the execution time of a single bagging cycle was 39.6s.

The grounding grid of some substation shows severely corrosion, which affects the safe running of power grid. Galvanized steel is widely used in grounding grid. However, the galvanized steel is easy to corrosion in alkaline soil. In this paper, the corrosion behavior of galvanized steel was studied through accelerated corrosion test of burying specimens in laboratory soils and the corrosion rate was measured by electrochemical test. The corrosion products and corrosion appearance were analyzed by means of SEM, and XRD. The results show that pitting corrosion and localized corrosion were observed on the surface of the galvanized steel, the corrosion products were rough and loose, indicating no protection, the corrosion products of galvanized steel were ZnO,FeO(OH),FeCl3,Zn3O(SO4)2,and ZnSO3·2.50H2O. Electrochemical test show that the corrosion rate of galvanized steel in the later corrosion stage is higher than in the initial corrosion stage.

Nanoshells have been previously shown to tune absorption frequencies efficiently. What will happen when a nanoshell embeds on a small core system? A theoretical model that a core composed of gold is embedded within a nanoshell of Au/Ag is constructed to answer this question. The calculations based on the discrete dipole approximation (DDA) method are performed and proved to converge accurately by satisfying the usual criteria related to the applicability of the DDA. The results show that the nanoshells in the core/shell system greatly influence the surface plasmon resonance (SPR). Indeed, the shell frequency is tuned to match the optical properties of the absorbing core leading to hybridization/mixing and possibly overall enhancement of absorption cross-section. The calculation of the field enhancement also shows that the location of the field enhancement is specified by the different resonance patterns.

The radiofrequency-optical double magnetic resonance in cesium atoms filled in a vapor cell is investigated experimentally. One resonant signal involving spin-exchange collisions is observed in the MZ type magnetic resonance spectrum. We solve Liouville equations describing the dynamics of the system and analyze the role of the spin-exchange collisions in the atomic population distributions under resonant conditions. The theoretical calculations agree very well with the experimental results. In contrast with the normal magnetic resonance, the collision induced magnetic resonance exhibits the interesting saturation effect: both the signal amplitude and the signal linewidth are nearly constant when the laser intensity is above a moderate threshold value, which can be useful for precision measurements of the geomagnetic field.

The spatial and temporal variation of major ions (Ca2+, Mg2+, Na+, K+, NH 4 + , SO 4 2 - , NO 3 - and Cl−) in Himalayan snow and ice is investigated by using two snow pits from the East Rongbuk glacier (28°01′N, 86°58′E, 6500 m a.s.l.), one snow pit from the Nangpai Gosum glacier (28°03′N, 86°39′E, 5700 m a.s.l.), one snow pit from the Gyabrag glacier (28°11′N, 86°38′E, 6303 m a.s.l.), and three ice cores from the Sentik (35°59′N, 75°58′E, 4908 m a.s.l.), Dasuopu (28°33′N, 85°44′E, 7000 m a.s.l.), and East Rongbuk (27°59′N, 86°55′E, 6450 m a.s.l.) glaciers, respectively. In general, the major ions show a significant seasonal variation, with high concentrations during the non-monsoon (pre-monsoon and post-monsoon) season and relatively low concentrations during the monsoon season. Monsoon precipitation with high local/regional dust loading related to summer circulation is possibly responsible for the high concentrations occurring sporadically during the monsoon season. The crest of the Himalayas is an effective barrier to the spatial distribution of Na+, Cl− and NH 4 + concentrations, but not to the major ions associated with dust influx (e.g. Ca2+ and Mg2+). Atmospheric backward trajectories from the HYSPLIT_4 model used in identifying chemical species sourcing suggest that the major ions in the Himalayan snow and ice come mainly from the Thar Desert located in the North India, as well as West Asia, or even the distant Sahara Desert in the North Africa during the winter and spring seasons. This is different from the conventionally assumed arid and semi-arid regions of the central Asia. Factors, such as different vapor sources due to atmospheric circulation patterns and geographical features (e.g. altitude, topography), may contribute to the differences in major ionic concentrations between the western and eastern Himalayas.

A special bifilar 40t electroslag remelting(ESR) furnace for slab products has been fabricated to produce heavy plates for special application. The slab ingots were rolled to heavy plates, and then the mechanical properties of which were investigated. The impact toughness of heavy plates with different position, directions and under welding condition were performed at the temperature ranging from -70°C to room temperature. The tensile experiments at room temperature were carried out to check the tensile properties of heavy plates in different position, directions and under welding condition. The secondary cooling technology developed improves greatly the quality of solidification. Adjusting taper of the mold and using CaF2-CaO-Al2O3-SiO2-MgO slag are necessary for improving surface quality of the ESR slab. The ESR slabs with the maximum thickness of the world in size of 980 mm thickness, 2000 mm wideness and 2800 mm length have been produced successfully. The heavy plates with 410 mm in thickness can be obtained after rolling the 40 tons ESR slabs. The results of mechanical properties show that the heavy plates produced by ESR furnace for slab products exhibits excellent ductility, impact and isotropic properties in different position, directions and under welding condition.

The relevance of pilus-related genes to motility, pilus structure on the cell surface and competency of natural transformation was studied by gene disruption analysis in the unicellular motile cyanobacterium Synechocystis: sp. PCC 6803. The genes disrupted in this study were chosen as related to the pil genes for biogenesis of the type IV pili in a Gram-negative bacterium Pseudomonas aeruginosa. It was found that motility of Synechocystis cells was lost in the mutants of slr0063, slr1274, slr1275, slr1276, slr1277 and sll1694 together with a simultaneous loss of the thick pili on the cell surface. Competency of the natural transformation was lost in the mutants listed above and slr0197-disruptant. The gene slr0197 was previously predicted as a competence gene by a search with sequence-independent DNA-binding structure [Yura et al. (1999) DNA Res. 6: 75]. It was suggested that both DNA uptake for natural transformation and motility are mediated by a specific type IV-like pilus structure, while a putative DNA-binding protein encoded by slr0197 is additionally required for the DNA uptake. Based on the homology with the pil genes in P: aeruginosa, slr0063, slr1274, slr1275, slr1276, slr1277 and sll1694 were designated pilB1, pilM, pilN, pilO, pilQ and pilA1, respectively. The gene slr0197 was designated comA.

A method for indirectly determining the molybdenum in Chinese herbal medicine by butanol extraction and dilute hydrochloric acid dissolution was established for atomic fluorescence spectrometry. The molybdoarsenate heteropoly acid, formed in the presence of As(V) and ammonium molybdate in 0.3 mol x L(-1) sulphuric acid medium, was separated and enriched in the organic solvent, then the evaporation of organic reagent was implemented and the left residue was dissolved in dilute hydrochloric acid in which the arsenic content was determined on behalf of molybdenum. In the optimum experimental conditions, molybdenum content in 0-15 microg x L(-1) range depicts a good linear relationship, the detection limit and relative standard deviation of 0.44 microg x L(-1) and 1.1% were obtained, respectively. Spiked Chinese herbal medicine samples were determined with the proposed method, and recoveries of 95.6%-101.3% were achieved.

In this paper, a new method was developed for indirect determination of iodine with methyl isobutyl ketone (MIBK) extraction by atomic fluorescence spectrometer (AFS). Based upon the complex, which can be extacted perfectly by MIBK, formed between I- and Hg2+ in 0.1 mol x L(-1) of nitric acid, indirectly measuring the iodine in organic phase becomes possible. The effects of extraction conditions and other influence factors were investigated. Under the optimized experimental conditions, the results showed that the linearity between its absorbance and the concentration of iodine was 0-12 microg x L(-1), the detection limit is 0.14 microg x L(-1), and the relative standard deviation is 3.3%. The method has been applied to the determination of iodine in eggs, and the recoveries are in the range of 101.8%-110.4%.

To study the effect of arsenic trioxide (As2O3) and all-trans retinoic acid (ATRA) on human cervical carcinoma HeLa cell line.HeLa cells were treated with As2O3 and ATRA. The cell proliferation was evaluated by MTT assay. The expressions of NDRG-1 protein and mRNA were determined by Western blot and RT-PCR analysis.MTT assay showed that As2O3 and ATRA inhibited the growth of human cervical carcinoma HeLa cells in vitro in a dose- and time-dependent manner. Western blot and RT-PCR techniques showed that As2O3 and ATRA down-regulated the expressions of NDRG-1 protein and mRNA (P0.05).As2O3 and ATRA can significantly inhibit the growth and proliferation of HeLa cells. The reason of these changes may be related with the down-regulation of expression of NDRG-1.