Understanding the growth mechanism of single-walled carbon nanotubes (SWCNTs) and achieving selective growth requires insights into the catalyst structure-function relationship. Using an in situ ...aberration-corrected environmental transmission electron microscope, we reveal the effects of the state and structure of catalysts on the growth modes of SWCNTs. SWCNTs grown from molten catalysts via a vapor-liquid-solid process generally present similar diameters to those of the catalysts, indicating a size correlation between nanotubes and catalysts. However, SWCNTs grown from solid catalysts via a vapor-solid-solid process always have smaller diameters than the catalysts, namely, an independent relationship between their sizes. The diameter distribution of SWCNTs grown from crystalline Co
7
W
6
, which has a unique atomic arrangement, is discrete. In contrast, nanotubes obtained from crystalline Co are randomly dispersed. The different growth modes are linked to the distinct chiral selectivity of SWCNTs grown on intermetallic and monometallic catalysts. These findings will enable rational design of catalysts for chirality-controlled SWCNTs growth.
The state and atomic structure of the catalysts determine the growth modes and structure of single-walled carbon nanotubes.
A comprehensive investigation of the signal-to-noise ratio (SNR) of the microwave photonic filter (MPF) with an interferometric structure based on an incoherent broadband optical source (IBOS) is ...presented from the time, and frequency domains, respectively. The interferometric structure, and the IBOS in the MPF result in a beneficial single-bandpass radio-frequency (RF) response. However, the IBOS adds a large noise to the filtered RF signal. Therefore, the analysis of the SNR is of great importance for the design of this kind of MPFs. Theoretical analysis shows that the SNR is a function of the center frequency of the passband, the modulation index, the chromatic dispersion, and the shape of the IBOS. An experiment is performed to verify the theory, and experimental results agree well with the theoretical calculation.
Currently, 19 disease-modifying therapies (DMTs) have been approved for the treatment of patients with relapsing forms of multiple sclerosis (RMS).
The objective of this study was to conduct a ...systematic review and network meta-analysis to evaluate the efficacy and safety of DMTs in adults with RMS.
We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, the Food and Drug Administration, and European Medicines Agency websites for randomized controlled trials (RCTs) (from inception to July 2021). Eligible RCTs evaluated approved treatments for RMS as monotherapy and reported at least one of the primary outcome measures of interest. The primary outcome was efficacy (annualized relapse rate and 12-week confirmed disability progression) and safety (serious adverse events AEs and discontinuation due to AEs). We assessed the risk of bias (RoB) of included studies using the Cochrane RoB tool version 2.0 (https://www.bmj.com/content/343/bmj.d5928) for RCTs. Surface under the cumulative ranking (SUCRA) was used to rank therapies and to assess quality of general evidence, respectively. The Grading of Recommendations Assessment, Development and Evaluation framework was used to rank therapies and to assess quality of general evidence.
A total of 43 records represent 45 RCTs selected for network meta-analysis. In total, 30,720 participants (median of 732; interquartile range: 248-931) were included, of which 67% were female. By SUCRA analysis, alemtuzumab (94.3%) presented the highest probability of being the best alternative for annualized relapse rate, whereas ofatumumab (93.5%) presented the highest probability of being the best alternative for 12-week confirmed disability progression. Interferon beta-1b subcutaneous (87.0%) presented the highest probability of the best safety among all DMTs for serious AEs, whereas alemtuzumab (92.4%) presented the highest probability of the best safety among all DMTs for discontinuation due to AEs.
Network meta-analysis shows that alemtuzumab and ofatumumab present the highest efficacy among DMTs. Because there is little difference between these probabilities for many treatments, health professionals should use clinical shared decision making when formulating treatment plans with patients.
A photonic microwave downconverter with improved conversion efficiency and spurious-free dynamic range (SFDR) is proposed and experimentally demonstrated based on a dual-parallel Mach-Zehnder ...modulator (DPMZM) and a digital signal post-processing algorithm. The radio frequency (RF) signal and the local oscillator (LO) signal are fed to the two sub-MZMs of the DPMZM, respectively, leading to an infinite isolation between the RF and LO ports. By biasing the two sub-MZMs and the parent MZM of the DPMZM at the minimum transmission point, the optical carrier can be greatly suppressed. As a result, the conversion efficiency is improved for the same power impinged on the photodetector. A preliminary experiment shows that a conversion efficiency of -12.7 dB can be achieved. On the other hand, without emulating the inverse link transfer function, where exact parameters of the photonic link should be known, a simple post-processing algorithm which just needs the modulation index of the LO signal is employed to suppress the intermodulation distortion products. The SFDR of the downconverter is improved from 101.5 dB · Hz 2/3 to 114.5 dB · Hz 4/5 by using the proposed digital linearization algorithm.
Probiotics have been documented to promote growth, immunity, and disease resistance in farmed fish. In the present study, we aimed to evaluate single or conjoint effects of some lactic acid bacteria ...(LAB), namely,
Lactococcus lactis
,
Lactobacillus rhamnosus
, and
Enterococcus faecalis
on the growth performance, immune response, and disease resistance of
Carassius auratus
. Fish were fed a basal diet supplemented with
L. lactis
(group B),
L. rhamnosus
(group C),
E. faecalis
(group D),
L. lactis
+
L. rhamnosus
(group E),
L. rhamnosus
+
E. faecalis
(group F),
L. lactis
+
E. faecalis
(group G), and
L. lactis
+
L. rhamnosus
+
E. faecalis
(group H) at 5.0 × 10
8
CFU/g diet for 34 days. After feeding, the final body weight (FBW), weight gain (WG), specific growth rate (SGR), and survival had significantly increased (
p
< 0.05) for group E. The results indicated that single or conjoint administration of LAB induced high levels of IgM, LZM, AKP, and SOD activity in serum, which may effectively induce humoral immunity, and group E induced even higher levels. At the same time, when compared to the basal diet (group A), the results of qPCR showed that probiotic administration significantly upregulated (
p
< 0.05) the expression of IL-10, IL-1β, TNF-α, and IFN-γ in the spleen, kidney, liver, and intestine of
C. auratus
. After challenge with the
Aeromonas hydrophila
, the survival rates in all probiotic-fed groups were significantly higher (
p
< 0.05) than those of group A, and the relative protection rates of groups B, C, D, E, F, G, and H were 27%, 30.7%, 40.94%, 42.32%, 39.38%, 33.61%, and 37.5%, respectively. Our data indicated that probiotics could promote growth, enhance immune indicators, and enhance immune capacity. In summary, combined administration of probiotics had a better effect on
C. auratus
. This experiment could provide a reference for the optimal combination of probiotic additives for aquatic animals.
A one‐step anisotropic etching method is developed to specifically obtain armchair‐edged graphene directly from graphite flakes on various substrates. The armchair edge structure of the produced ...graphene is verified by the atomic resolution images obtained from the fluid mode peakforce tapping AFM and the relatively high intensity of D band in the Raman spectra.
Due to system instability and other reasons, the actual range sampling frequency (RSF) of the system may deviate from the ideal value for the microwave photonic synthetic aperture radar (SAR). This ...deviation may lead to severe residual range cell migration (RCM) and even range defocus after imaging, which can seriously affect the image quality. To resolve this problem, this article proposes an airborne microwave photonic SAR imaging algorithm based on inaccurate system parameter estimation. First, the algorithm estimates and compensates for the range spatial-variant motion error to eliminate the effect of this motion error on the remaining RCM and range defocus. Second, based on the minimum entropy criterion of the image, we use the optimization model to estimate the actual RSF. Finally, the existing wide-beam autofocus method is used to correct the azimuth spatial-variant motion error. The simulation data and the measured data processing results verify the effectiveness of the proposed method.
A frequency tunable optoelectronic oscillator based on a directly modulated distributed-feedback (DFB) semiconductor laser under optical injection is proposed and experimentally demonstrated. Through ...optical injection, the relaxation oscillation frequency of the DFB laser is enhanced and its high modulation efficiency can enable the loop oscillation with a RF threshold gain of less than 20 dB. The DFB laser is a commercial semiconductor laser with a package of 10 GHz, and its packaging limitation can be overcome by optical injection. In our scheme, neither a high-speed external modulator nor an electrical bandpass filter is required, making the system simple and low-cost. Microwave signals with a frequency tuning range from 5.98 to 15.22 GHz are generated by adjusting the injection ratio and frequency detuning between the master and slave lasers. The phase noise of the generated 9.75 GHz microwave signal is measured to be -104.8 dBc/Hz @ 10 kHz frequency offset.
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