Solid fuel ramjets (SFRJs) have the advantages of light weight, simple structure, high reliability, high economy efficiency etc. During the transient situation, their actual time fuel consumption can ...be different from the simple linear control rules due to the limit of mechanical structures. The volume effect can also be treated as an influence factor of fuel. As a result, the dynamic characteristics of fuel will influence the transient performance of SFRJs. To better understand its impact, in-house models for SFRJs' transient performance and fuel's dynamic characteristics are built and simulated. During accelerating and decelerating processes, the actual time fuel consumption has characteristics of time-lag. There will exist thrust lost or superfluous thrust. Compared with acceleration processes, the dynamic characteristics of fuel would be more influential in deceleration processes.
Ramjets can provide higher specific impulse comparing to turbojet or turbofan engines. The influence of the volume effect when ramjets are accelerating or decelerating are studied by getting thrusts' ...and fuel consumptions' data. To that end, in-house models for ramjets' transient performance and volume effects are built and used for simulation. During both accelerating and decelerating processes, the volume effect will cost extra time and cause thrust loss or gain for the ramjet to balance its performance. In a decelerating then accelerating process, the minimum thrust can be larger. The volume effect will be more noticeable when the ramjet's thrust is comparatively low.
A new technique for estimating quiet day curve（QDC） was suggested. To validate the new approach, QDCs were derived from data acquired by the imaging riometer installed at the Chinese Zhongshan ...Station in Antarctic. The evaluation was performed by comparing the difference between QDC derived by the new technique and those derived by Tanaka＇s technique. The results were discussed in terms of the diurnal variation and discrepancy. Also, cosmic noise absorption（CNA） images were built using both techniques in order to evaluate the implications of the changes when obtaining them using different methods of the QDC determination. The influence of the multiplicative factor value on the QDC determination in Tanaka＇s technique was evaluated.
This article develops a complete theory of the switchless Class-G (SLCG) power amplifier (PA) and proposes a new design method that allows for operating commercial packaged transistors in ...high-efficiency SLCG mode over a wide frequency band. It starts with a comprehensive analysis that investigates the impact of various transistor and circuit parameters on the SLCG PA's key performances. Then, design equations are derived to produce SLCG prototypes with optimal back-off efficiency and gain flatness. Moreover, to overcome the difficulty of applying classical SLCG circuits to packaged devices, a new SLCG output combining network (OCN) is developed to absorb various transistors and package parasitic while maintaining the load conditions that enable the wideband SLCG operation. This expands the applicable scope of the SLCG technique and yields packaged-transistor-based, wideband, and high-efficiency SLCG PAs. For validation, a 1-3-GHz SLCG PA is designed using the proposed method with commercial packaged transistors. Measurements under continuous-wave (CW) excitations reveal that, over 1-3 GHz, the proposed SLCG PA can provide the saturation output power (<inline-formula> <tex-math notation="LaTeX">P_{\mathrm {sat}} </tex-math></inline-formula>) of 36.5-38.7 dBm and deliver the drain efficiency (DE) of 39.2%-49.1%, 45.4%-51.2%, and 47.8%-57.7% at power levels that are 7.5-, 6-, and 0-dB back-off from <inline-formula> <tex-math notation="LaTeX">P_{\mathrm {sat}} </tex-math></inline-formula>, respectively. Moreover, when excited by a 40-MHz 64-quadrature amplitude modulation (QAM) modulated signal over 1-3 GHz, the PA realizes an average DE of 39%-49.2% at an average output power of 28.8-31.6 dBm and maintains an error vector magnitude (EVM) of about 1.2% and adjacent channel power ratio (ACPR) of below −46 dBc after digital predistortion (DPD).
This research designeded to: 1. Analyze the efficacy and safety of Palbociclib treatment in HR-positive and HER2-negative (HR + /HER2-) metastatic breast cancer(MBC) patients. 2. Establish and ...validate a nomogram model for predicting the progression-free survival (PFS) rates of 6 months, 12 months, and 18 months in HR + /HER2- MBC patients after receiving Palbociclib plus endocrine therapy (ET).
1. This research retrospectively analyzed the efficacy and safety of Palbociclib combined with ET in 214 patients with HR + /HER2- MBC. 2. A nomogram was designed and constructed with the retrospective clinical data of 214 patients with HR + /HER2- MBC who received Palbociclib plus ET at Zhejiang Cancer Hospital in China from August 2018 to August 2022. Among these patients, 161 were randomly assigned to the training cohort, while 53 to the validation cohort. The predictive accuracy of the nomogram was assessed through the analysis the area under the receiver operating characteristic(ROC) curve, calibration curve, and decision curve analysis(DCA).
1. Median PFS was 7.17 months (95% CI: 7.61-10.05 months), with an objective response rate (ORR) of 2.80% and a disease control rate (DCR) of 34.58%. The most prevalent grade 3-4 adverse event was neutropenia (38.79%). 2. Multiple variable analysis of the training set revealed that age < 60 years old, PR < 20%, Ki-67 ≥ 20%, luminal B molecular subtype, primary resistance to ET, receipt of late-stage chemotherapy, and presence of liver metastasis or ≥ 2 visceral metastases were independent prognostic factors associated with poor PFS (P < 0.05). Then, the predictive model underwent development and validation utilizing the aforementioned parameters. On the one hand, the area under the ROC curve (AUC) values of the training set at 6 months, 12 months, and 18 months were 0.771, 0.783, and 0.790, respectively, indicating a strong predictive ability of the developed model. On the other hand, the AUC of the validation set at 6 months, 12 months, and 18 months were 0.720, 0.766, and 0.754, respectively, suggesting the favorable discriminatory ability of the model. The calibration curves also exhibited a good fit with the ideal curves, and the DCA demonstrated the clinical applicability of the model. The nomogram's different scores could distinguish PFS.
This retrospective study demonstrates the efficacy of Palbociclib in Chinese breast cancer patients. Moreover, the clinical parameters showed a significant association with the prognosis of HR + /HER2- MBC, and the prognostic models constructed based on these variables also displayed robust predictive power, which could offer more intuitive and convenient references for clinical doctors to formulate follow-up treatment plans.
Exosome-based liquid biopsies possess great potential in monitoring cancer development However, current exosome detection biosensors require large exosome volumes, showing the weak detection ...sensitivity. Besides, these methods pay little attention to in situ analysis of exosomes, hence limiting the provision of more accurate clinically-relevant information. Herein, we develop an innovative label-free biosensor combining the low-cost thermophoretic enrichment method with the surface-enhanced Raman spectroscopy (SERS) detection. Based on the thermophoretic enrichment strategy, exosomes and gold nanoparticles can be enriched together into a small area with a scale of 500 μm within 10 min. The Raman signals of various exosomes derived from normal, cancerous cell lines and human serum are dynamically monitored in situ, with the limit of detection of 102–103 particles per microliter, presenting higher sensitivity compared with the similar label-free SERS detection. The spectral data set of different exosomes is applied to train for multivariate classification of cell types and to estimate how the normal exosome data resemble cancer cell exosome. The reliable classification and identification of different exosomes can be realized. The current biosensor is convenient, low-cost and requires small exosome volumes (∼3 μL), and if validated in larger cohorts may contribute to the tumor prediction and diagnosis.
In recent years, surface-enhanced Raman spectroscopy (SERS) has been widely used in various fields for the rapid detection of trace-level molecular targets. In this study, we have developed a simple ...and effective solution-based SERS protocol to improve the activity for the detection of cationic dye molecules in aquaculture. The polystyrene sulfonate functionalized gold nanobipyramids (PSS–Au BPs) were synthesized from the cetyltrimethylammonium bromide (CTAB) reaction system followed by the ligand exchange process. The halide ions-induced aggregation of PSS-Au BPs was carried out by using four type of different salts such as NaCl, NaBr, MgCl2 and MgSO4 to investigate their influence on the SERS activity. The results demonstrate that the ionic strength of the solution has an important impact on the colloidal stability and SERS activity. The PSS-Au BPs show an improved SERS sensitivity at lower concentrations of the aggregating agents in solution-based SERS by detecting the crystal violet (CV) molecules with a limit of detection (LOD) to 3.28 × 10−11 M. Furthermore, to demonstrate the generality of our proposed strategy, trace amounts of three more dyes such as malachite green (MG), methylene blue (MB), and rhodamine 6G (R-6G), as well as other molecules such as thiram and bisphenol-S were also detected. This protocol not only provides a method for rapid on-site detection of trace-level molecules but can also be applied to other SERS-based analysis.
Very simple and effective solution-based SERS detection system by using polystyrenesulfonate functionalized Au BPs. Display omitted
•A simple ligand exchange protocol was introduced to modify the surface of CTAB Au BPs by polystyrene-sulfonate ligand.•The PSS-Au BPs were used to detect the cationic dye molecules in solution-based SERS detection.•Multivalent salts were used to investigate their effect on solution-based SERS detection by using PSS-Au BPs.•The addition of aggregating agent in colloidal solution improved the SERS signal intensity and limit of detection.•The PSS-Au BPs were used for real sample detection of malachite green and methylene blue in fish pond water.
To achieve ultrasensitive detection of trace targets through solution-based surface-enhanced Raman spectroscopy (SERS), direct adsorption of the target molecules on a SERS-active surface is vital. In ...this work, cetyltrimethylammonium bromide (CTAB)-capped gold nano-bipyramids (Au BPs) with different aspect ratios (ARs) are prepared and the surface is successfully modified by a simple ligand exchange method. Cysteamine-capped gold nano-bipyramids (cyst-Au BPs) are obtained by means of replacement of CTAB by cysteamine using Au–S covalent bonding and applied in the solution-based SERS detection of different pigment molecules, which always have weak affinity to the gold surface. The hydrogen bonding between the pigment molecule and cysteamine causes the aggregation of Au BPs to generate local electromagnetic field enhancement. The influence of the AR and concentration of Au BPs on SERS properties is investigated. The SERS detection of weak-affinity molecules to an extremely low limit shows that the cyst-Au BPs are highly sensitive compared to CTAB-capped Au BPs. The limit of detection (LOD) of allura red as low as 0.1 ppb and that of sunset yellow as low as 1 ppb show that the proposed strategy has many advantages due to its simplicity and fast and rapid detection for the sensitivity analysis of weak-affinity molecules.
Surface-enhanced Raman scattering (SERS) possesses the advantage that directly detects target analytes in solution with high specificity and sensitivity without complicated pretreatment procedures. ...It remains a challenge in most practical applications to achieve molecule sensitivity in any highly diluted solutions. Here, we develop a robust and practical molecular enrichment strategy that can effectively confine analyte molecules and Au nanoparticles together in a short time into a small-sized sensitive region on a needle tip, based on the Leidenfrost phenomenon and capillary force. In this strategy, the Leidenfrost evaporation phenomenon maintains the analytes droplet in a Cassie state based on a levitating force, and at the same time, a hung needle tip anchors the droplet based on the capillary force. After 1–2 min quick evaporation, more than 98% Au nanoparticles and analytes can be condensed into an around 0.5 mm small size area on the needle tip. Due to the significant enrichment capability and reproducibility, the SERS measurement enables to achieve the limit of detection (LOD) down to 0.08 nM (at an S/N ratio of 3) for crystal violet (CV) molecules and to nM level for several types of pesticide molecules (glyphosate, carbendazim, thiram and choline) in ethanol solution. The strategy was also applied to the detection of CV molecules in mixture pigments solution, thiram in spiked environment water samples, with good selectivity and sensitivity. In addition, using the high thermal conductivity substrate without additional surface modification, this enrichment SERS detection may open the possibility of universal applications due to its facile and cost-effective. The accurate site of the needle tip offers great practical potentials for on-site identification by using a handheld Raman spectrometer.
Display omitted
•Combining the partial Leidenfrost evaporation and tip enrichment method, it can greatly accelerate the enrichment process.•The common flat substrates with good thermal conductivity are suitable for this method to reduce the operation difficulty.•The final enrichment tiny area of tip can be easily located under the laser spot to increase the sensitivity of detection.•The novel method exhibits a wide detection range with a LOD down to nM for the poorly soluble pesticides.
IGPD is an essential metalloenzyme that catalyzes histidine biosynthesis. We found that its C-terminus loop region has a vital role in determining enzyme activity but has been hardly mentioned ...before. In this work, we focused on the dynamic feature and function of C-Loop in Arabidopsis thaliana and Saccharomyces cerevisiae IGPD (At_IGPD and Sc_IGPD, respectively). Due to the high flexibility of this region, we performed a total of 3.4 μs of accelerated molecular dynamics simulation to enhance sampling. Inhibitor C348 in At-IGPD exhibited instability in the later stage of simulation, while the characteristic sequence in Sc_IGPD reduced solvent interference and significantly restrained the interaction mode. For the C-Loop-assisted ligand-binding process, we proposed a “Lock-Lid” model. Meanwhile, the dissociated ligand in At_IGPD served as a probe, a metastable pocket was determined at the root of C-Loop, and its rationality was proved by theoretical verification and enzyme mutation experiments. This study complemented the important structural features of C-Loop and provided a basis for the design of selective inhibitors. Considering the absence in mammals, we suggested that IGPD could be a promising germicide target.
