Effective Bidirectional Mott-Schottky Catalysts Derived from Spent LiFePO4 Cathodes for Robust Lithium-Sulfur Batteries.

It is deemed as a tough yet profound project to comprehensively cope with a range of detrimental problems of lithium-sulfur batteries (LSBs), mainly pertaining to the shuttle effect of lithium polysulfides (LiPSs) and sluggish sulfur conversion. Herein, a Co2P-Fe2P@N-doped carbon (Co2P-Fe2P@NC) Mott-Schottky catalyst is introduced to enable bidirectionally stimulated sulfur conversion. This catalyst is prepared by simple carbothermal reduction of spent LiFePO4 cathode and LiCoO2. The experimental and theoretical calculation results indicate that thanks to unique surface/interface properties derived from the Mott-Schottky effect, full anchoring of LiPSs, mediated Li2S nucleation/dissolution, and bidirectionally expedited "solid⇌liquid⇌solid" kinetics can be harvested. Consequently, the S/Co2P-Fe2P@NC manifests high reversible capacity (1569.9 mAh g-1), superb rate response (808.9 mAh g-1 at 3C), and stable cycling (a low decay rate of 0.06% within 600 cycles at 3C). Moreover, desirable capacity (5.35 mAh cm-2) and cycle stability are still available under high sulfur loadings (4-5 mg cm-2) and lean electrolyte (8 µL mg-1) conditions. Furthermore, the as-proposed universal synthetic route can be extended to the preparation of other catalysts such as Mn2P-Fe2P@NC from spent LiFePO4 and MnO2. This work unlocks the potential of carbothermal reduction phosphating to synthesize bidirectional catalysts for robust LSBs.

Ultralow-level all-optical self-switching in a nanostructured moiré superlattice.

We report an all-optical self-switching performed at an ultralow-level of intensity in a nanostructured moiré superlattice on a silicon platform. The moiré superlattice was formed by twisting two sets of triangular lattices in a silicon membrane in the same layer with a twist angle of 9.43°. The near flatband was formed, and the electric field was well confined in the center of the superlattice, which enabled all-optical switching under an ultralow intensity when the Kerr nonlinearity of silicon was considered. The intensity, which was reduced to 300 W/m2 and even 20 W/m2, can cause the transmittance of the nanostructure to change from 0 to 80% under x- and y-polarized pump light, respectively, and could be further decreased by optimizing the nanostructure or nonlinear materials. The results indicate that moiré superlattices fabricated from nonlinear materials are promising for integrated all-optical devices.

Comparison of contrast-enhanced fat-suppressed T1-3D-VIBE and T1-TSE MRI in evaluating anal fistula.

OBJECTIVE: To evaluate the accuracy of contrast-enhanced (CE) fat-suppressed three-dimensional (3D) T1-weighted imaging with volumetric interpolated breath-hold examination (FS-T1-3D-VIBE) and fat-suppressed T1-weighted turbo spin echo (FS-T1-TSE) sequence in characteristics of anal fistula. METHODS: One hundred and two patients underwent perianal CE-MRI examination on a 3T scanner including FS-T1-3D-VIBE and FS-T1-TSE sequences before surgery. The performance of each sequence was evaluated in terms of fistula classification, clarity of internal opening, number and position of internal openings including the distance between internal opening and anal verge, presence of secondary tracts and blind-ending sinus tracts. MRI findings were compared with surgical findings. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of fistula, gluteus maximus, and subcutaneous fat were compared between CE FS-T1-TSE and CE FS-T1-3D-VIBE. RESULTS: Compared with CE FS-T1-TSE, CE FS-T1-3D-VIBE displayed more accurate in secondary tract, lithotomy position of the internal opening and the distance between internal opening and anal verge (P < 0.05). CE FS-T1-3D-VIBE was found superior to CE FS-T1-TSE in the clarity of the internal openings and in the diagnostic accuracy of blind-ending sinus tracts and complex fistulas in Standard Practice Task Force classification (P < 0.05). CE FS-T1-3D-VIBE achieved higher SNRs and CNRs in fistula and gluteus maximus than CE FS-T1-TSE (P ≤ 0.001). CONCLUSION: CE-MRI of FS-T1-3D-VIBE might be a more valuable noninvasive technique than FS-T1-TSE to evaluate the anal fistula on evaluating the lithotomy position of internal opening, distance between internal opening and anal verge, clarity of internal opening, secondary tract, blind-ending sinus tract and classification of the complex fistula. The trial registration number for this prospective trial was Chi-TR1800020206 and the trial registration date was December 20, 2018.

Performance of 2D BLADE turbo gradient- and spin-echo diffusion-weighted imaging in the quantitative diagnosis of recurrent temporal bone cholesteatoma.

BACKGROUND: Diffusion-weighted imaging (DWI) has become an important tool for the detection of cholesteatoma. The purpose of this study was to explore the value of 2D BLADE turbo gradient- and spin-echo imaging (TGSE BLADE) DWI in the quantitative diagnosis of recurrent temporal bone cholesteatoma (CS). METHODS: From March 2018 to October 2021, 67 patients with suspected recurrence of temporal bone CS after assessment by clinical otorhinolaryngologists who had undergone previous ear surgery for CS were prospectively evaluated by magnetic resonance imaging (MRI). Two radiologist assessed images independently. Quantitative parameters such as signal intensity ratio (SIR) calculated using, as a reference, the inferior temporal cortex (SIRT) and the background noise (SIRN), apparent diffusion coefficient (ADC) value, and ADC ratio (with pons as reference) measured on TGSE BLADE sequences were assessed. Using receiver operating characteristic (ROC) curve analysis, the optimal threshold and diagnostic performance for diagnosing recurrent CS were determined. Pair-wise comparison of the ROC curves was performed using the area under the ROC curve (AUC). RESULTS: Finally, 44 patients were included in this study, including 25 CS and 19 non-cholesteatoma (NCS). Mean SIRT and mean SIRN on TGSE BLADE DWI were significantly higher for CS than NCS lesions (p < 0.001). Meanwhile, mean ADC values and mean ADC ratios on ADC maps were significantly lower in the CS group than in the NCS group (p < 0.001). According to ROC analysis, the diagnostic efficacy of quantitative parameters such as SIRT (AUC = 0.967), SIRN (AUC = 0.979), ADC value (AUC = 1.0), and ADC ratio (AUC = 0.983) was significantly better than that of qualitative DWI (AUC = 0.867; p = 0.007, 0.009, 0.011 and 0.037, respectively). CONCLUSIONS: Residual/recurrent temporal bone CS can be accurately detected using quantitative evaluation of TGSE BLADE DWI.

Fractionation analysis and risk assessment of potential toxic elements in reservoir sediments in central China.

The pollution of potential toxic elements (PTEs) in the environment is a persistent issue and draws public attention constantly. However, there is no study comprehensively assessing the PTE pollution of water supply reservoirs in central China. This study determined the total contents and fractions of seven PTEs in 10 water supply reservoirs of central China, and evaluated PTE pollution risks by adopting various models. The results indicated that PTE pollution in water supply reservoirs was lower comparing that in estuary or river sediments, and Mn (manganese) was the predominant PTE in central China reservoirs. Fractionation analysis revealed that for B1 fraction (exchangeable/acid-soluble fraction) of Mn, Zn (zinc) and B2 fraction (reducible fraction) of Pb (lead) was high, while the effective state portion of Cr (chromium) was small. The monomial potential ecological risk indices and Igeo values were low among most samples, indicating overall modest PTE pollution. However, the results of the individual contamination factor (ICF) suggested that Pb might lead to potential health risks to human beings.

Detection of cholesteatoma: 2D BLADE turbo gradient- and spin-echo imaging versus readout-segmented echo-planar diffusion-weighted imaging.

PURPOSE: This study is to compare the accuracy of 2D BLADE turbo gradient- and spin-echo imaging (TGSE BLADE) diffusion-weighted imaging (DWI) with that of readout-segmented echo-planar (RESOLVE) DWI in the detection of primary and residual/recurrent temporal bone cholesteatoma. METHODS: The prospective study population consisted of 58 patients who were underwent magnetic resonance (MR) imaging for the evaluation of suspected temporal bone cholesteatoma. Two radiologists independently evaluated the two sequences. Kappa (k) statistics, the intra-class correlation coefficient (ICC), and a paired t test were used for statistical analysis. RESULTS: Of the 58 patients included, all had histo-pathologically confirmed cholesteatomas. In ≤ 3 mm group (n = 13), TGSE BLADE sequence correctly identified all cases except one that was recorded as equivocal on both sequences because of high signal intensity on T1WI; while on RESOLVE sequences, 6 were positive, 4 were equivocal, and 3 were false negative. For > 3 mm group (n = 45), detection performance was similar between the two sequences. The mean ADC of cholesteatoma on TGSE BLADE DWI was 0.923 × 10-3 mm2/s, and the mean ADC of cholesteatoma on RESOLVE DWI was 0.949 × 10-3 mm2/s, with no significant difference in the mean ADC values of cholesteatoma measured on the two sequences (p = 0.9216). CONCLUSION: TGSE BLADE outperforms RESOLVE in the detection of small temporal bone cholesteatoma ≤ 3 mm.

Nitrogen addition exerts a stronger effect than elevated temperature on soil available nitrogen and relation to soil microbial properties in the rhizosphere of Camellia sinensis L. seedlings.

As the global climate changes, elevated atmospheric temperature and nitrogen (N) deposition co-occur in natural ecosystems, which affects rhizosphere soil nutrient by altering allocation of roots and its availability to soil microorganism. Elevated temperature in combination with N deposition is expected to affect soil available N and its relation to microbial properties, but this issue has not been extensively examined. Here, we investigated soil available N and its relation to microbial properties in rhizosphere of Camellia sinensis L. seedlings exposed to elevated temperature using a passive warming device in combination with N-added soil. Elevated temperature did not significantly affect soil pH, total organic carbon (TOC), total nitrogen (TN), the ratio of carbon and nitrogen (C:N ratio), total phosphorus (TP), available N ((N in ammonium (NH4+-N) and N in nitrate (NO3--N)) (NH4+-N + NO3--N)/TN, α-glucosidase (αG), ß-glucosidase (ßG), cellobiohydrolase (CBH), N-acetyl-glucosaminidase (NAG), and phenol oxidase (PPO) activities, while significantly stimulated root total length of tea seedlings (3.9%), root dry biomass (10.2%), soil microbial biomass carbon (MBC) (7.4%), microbial biomass nitrogen (MBN) (8.6%), and acid phosphatase (ACP) (8.8%). While N addition significantly (p < 0.05) stimulated root dry biomass of tea seedlings (14.1%), root total length (6.2%), root average diameter (6.7%), soil TN, available N, (NH4+-N + NO3--N)/TN, and MBN under elevated temperature. Soil aG, ßG, CBH, and ACP activity increase significantly (p < 0.05) under elevated temperature + N relative to elevated temperature alone. Generally, N addition led to increased available nitrogen and microbial properties in rhizosphere soil of tea seedlings exposed to elevated temperature by stimulating root properties, soil nitrogen, microbial biomass N, and enzyme activity. Redundancy analysis and Pearson correlation analysis suggested that N addition lead to higher correlation between soil available N and microbial properties exposed to elevated temperature. Our results indicated nitrogen addition exerts a stronger effect than elevated temperature on soil fertility and microbiological cycle in the rhizosphere of Camellia sinensis L. seedlings. The conclusion helps us understand the response mechanism of soil rhizosphere microenvironment to N deposition under global warming scenarios.

Antibiotic resistomes in water supply reservoirs sediments of central China: main biotic drivers and distribution pattern.

Water supply reservoirs form one of the critical drinking water resources. Their water quality directly affects human health. However, reservoir sediments have not received adequate attention in antibiotic resistance genes (ARGs) dissemination, though they reflect long-term ARGs contamination of water supply reservoirs. Moreover, the physicochemical parameters in water supply reservoir sediments are generally better than those in the other media. Thus, the main ARGs biotic drivers of the media would demonstrate their unique characteristics. In this study, sediment samples were collected from 10 water supply reservoirs in central China, and the antibiotic resistomes were determined with the metagenomic method. As revealed from the results, 174 ARGs (18 ARG types) were detected in the reservoir sediment. Besides, multidrug-, sulfonamide-, and vancomycin-ARGs were the dominant ARGs in the sediment samples. The macrolide-resistant Microcystis was prevalent (100% detection frequency with 0.35% average percentage) in reservoir sediments and posed potential risks to human health. Furthermore, the results of the Mantel test and VPA demonstrated that mobile genetic elements (MGEs) were the more essential biotic drivers in ARG contents of reservoir sediments rather than the bacteria community.

Histogram Analysis of Quantitative Susceptibility Mapping for the Diagnosis of Parkinson's Disease.

RATIONALE AND OBJECTIVES: To investigate the diagnostic performance of histogram analysis combined with quantitative susceptibility mapping (QSM) for differentiating Parkinson's disease (PD) patients from healthy controls. METHODS: We included 35 patients with PD diagnosed by two neurologists from August 2019 to January 2020 in our hospital in this prospective study. The clinical diagnosis was based on the Movement Disorder Society Clinical Diagnostic Criteria for PD. At the same time, 23 healthy volunteers matched for age and sex were recruited as controls. The Mini Mental State Examination, the third part of the Parkinson's Disease Rating Scale, the Hoehn & Yahr stages, and disease duration (year) were used to assess the PD patients. QSM was performed using a 3T MR scanner. The regions of interest were depicted according to the head of the caudate nucleus(CN), globus pallidus(GP), putamina (PUT), thalmus(TH), substantia nigra (SN), red nucleus(RN), and dentate nucleus. Then the corresponding histogram features were extracted. The Mann-Whitney U test was used to identify significant histogram features for differentiating PD patients from healthy controls. Area under the receiver operating characteristics curve (AUC) analysis was conducted to evaluate the diagnostic performance of all significant histogram features. Multivariate logistic regression analysis was performed to identify the best combined model for all seven nuclei. Differences among the AUCs were compared pairwise. RESULTS: Histogram features in all nuclei except TH showed significant differences between the groups. Among the single features, the 10th percentile of SN (SNP10) yielded the highest AUC of 0.894, with the highest specificity of 86.86% for differentiating PD patients from healthy controls. The 75th percentile of PUT (PUTP75) yielded the highest sensitivity of 97.14%. In the multivariate logistic regression analysis, SNP10 combined with PUTP75 yielded the highest diagnostic performance with the highest AUC of 0.911, the highest specificity of 91.30% and an excellent sensitivity of 92.40%. CONCLUSION: QSM combined with histogram analysis successfully distinguished PD patients from healthy controls, and the result was notably superior to the mean value.

BLADE turbo gradient- and spin-echo in the assessment of sinonasal lesions: a comprehensive comparison of image quality in readout-segmented echo-planar imaging.

BACKGROUND: A two-dimensional turbo gradient-echo and spin-echo diffusion-weighted pulse sequence with a non-Cartesian BLADE trajectory (TGSE BLADE) can eliminate image artifacts and distortion with clinically acceptable scan times. This process has the potential to overcome the shortcomings of current diffusion-weighted imaging (DWI) techniques, especially in the sinonasal region. PURPOSE: To investigate the feasibility of TGSE BLADE in the assessment of sinonasal lesions and compare the quality of TGSE BLADE with RESOLVE images both qualitatively and quantitatively. MATERIAL AND METHODS: A total of 36 patients with sinonasal lesions were included in this prospective study. DW images acquired using TGSE BLADE and RESOLVE were performed with the same acquisition time. Two independent observers evaluated the qualitative parameters (overall image quality, lesion visibility, and geometric distortion) and quantitative parameters (geometric distortion ratio [GDR], signal-to-noise ratio [SNR], contrast, contrast-to-noise ratio [CNR], and apparent diffusion coefficient [ADC] value) of the two sequences. RESULTS: Qualitative assessment revealed that TGSE BLADE exhibited higher overall image quality (P < 0.001) and lesion visibility (P < 0.001) and less geometric distortion (P < 0.001) than RESOLVE. Quantitative assessment showed that TGSE BLADE images exhibited higher contrast (P < 0.001) and CNR (P < 0.001) and lower GDR (P < 0.05) and SNR (P < 0.001) than RESOLVE images. The ADC value of TGSE BLADE was significantly lower than that of RESOLVE (P < 0.05). CONCLUSION: TGSE BLADE can reduce susceptibility artifacts and geometric distortion more than RESOLVE and appears to be a promising diffusion imaging sequence for the assessment of sinonasal lesions.

Frequent ploidy changes in Salicaceae indicates widespread sharing of the salicoid whole genome duplication by the relatives of Populus L. and Salix L.

BACKGROUNDS: Populus and Salix belong to Salicaceae and are used as models to investigate woody plant physiology. The variation of karyotype and nuclear DNA content can partly reflect the evolutionary history of the whole genome, and can provide critical information for understanding, predicting, and potentially ameliorating the woody plant traits. Therefore, it is essential to study the chromosome number (CN) and genome size in detail to provide information for revealing the evolutionary process of Salicaceae. RESULTS: In this study, we report the somatic CNs of seventeen species from eight genera in Salicaceae. Of these, CNs for twelve species and for five genera are reported for the first time. Among the three subfamilies of Salicaceae, the available data indicate CN in Samydoideae is n = 21, 22, 42. The only two genera, Dianyuea and Scyphostegia, in Scyphostegioideae respectively have n = 9 and 18. In Salicoideae, Populus, Salix and five genera closely related to them (Bennettiodendron, Idesia, Carrierea, Poliothyrsis, Itoa) are based on relatively high CNs from n = 19, 20, 21, 22 to n = 95 in Salix. However, the other genera of Salicoideae are mainly based on relatively low CNs of n = 9, 10, 11. The genome sizes of 35 taxa belonging to 14 genera of Salicaceae were estimated. Of these, the genome sizes of 12 genera and all taxa except Populus euphratica are first reported. Except for Dianyuea, Idesia and Bennettiodendron, all examined species have relatively small genome sizes of less than 1 pg, although polyploidization exists. CONCLUSIONS: The variation of CN and genome size across Salicaceae indicates frequent ploidy changes and a widespread sharing of the salicoid whole genome duplication (WGD) by the relatives of Populus and Salix. The shrinkage of genome size after WGD indicates massive loss of genomic components. The phylogenetic asymmetry in clade of Populus, Salix, and their close relatives suggests that there is a lag-time for the subsequent radiations after the salicoid WGD event. Our results provide useful data for studying the evolutionary events of Salicaceae.

Broadband and Ultra-Low Threshold Optical Bistability in Guided-Mode Resonance Grating Nanostructures of Quasi-Bound States in the Continuum.

We model optical bistability in all-dielectric guide-mode resonance grating (GMR) nanostructures working at quasi-bound states in the continuum (BICs). The complementary metal-oxide-semiconductor (CMOS) compatible material silicon nitride (SiN) is used for the design of nanostructures and simulations. The ultra-low threshold of input intensity in the feasible nanostructure for nanofabrication is obtained at the level of ~100 W/cm2 driven by quasi-BICs. Additionally, the resonance wavelength in the GMR nanostructure can be widely tuned by incident angles with the slightly changed Q-factor that enables the optical bistable devices to work efficiently over a wide spectrum. The impact of the defects of grating that may be introduced in the fabrication process on the optical properties is discussed, and the tolerance of the defects to the optical performance of the device is confirmed. The results indicate that the GMR nanostructures of broadband and ultra-low threshold optical bistability driven by quasi-BICs are promising in the application of all-optical devices.

Passively Q-Switched Yb:CALGO Laser Based on Mo:BiVO4 Absorber.

A stable, passively Q-switched Yb:CaGdAlO4 laser based on Mo:BiVO4 saturable absorber was demonstrated. Close observations of the structure and morphology of the nanoparticles by using transmission electron microscope, Raman spectrum and linear absorption were measured. The nonlinear transmission of Mo:BiVO4 was characterized by a 30 ps laser with a central wavelength of 1064 nm and a repetition rate of 10 Hz. The experimental maximum output power of the pulsed laser was 510 mW with a repetition rate of 87 kHz and pulse width of 3.18 µs, corresponding to a peak power of 1.84 W and a single pulse energy of 5.8 µJ. The experimental results indicate that Mo:BiVO4-SA is a great candidate for passively Q-switched lasers in the near infrared region.

Comparing compressed sensing breath-hold 3D MR cholangiopancreatography with two parallel imaging MRCP strategies in main pancreatic duct and common bile duct.

PURPOSE: To evaluate the image quality and image consistency between 3D Breath-hold (BH)-MRCP with parallel imaging (3D-BH-PI-MRCP) and 3D-BH compressed sensing (CS)-MRCP (3D-BH-CS-MRCP) in patients with suspected pancreaticobiliary diseases, compared with 3D navigator-triggered (NT)-MRCP. MATERIALS AND METHODS: The A total number of 109 patients who underwent 3D-NT-MRCP, 3D-BH-PI-MRCP and 3D-BH-CS-MRCP were prospectively enrolled in this study. The Friedman test was performed to compare quantitative values, image acquisition time, the presence of artifacts, overall image quality, and duct visualization among the three protocols. Additionally, we compared 3D-BH-PI-MRCP and 3D-BH-CS-MRCP with 3D-NT-MRCP in morphological consistency of main pancreatic duct and common bile duct (CBD) based on overall image quality score of = 4. RESULTS: Three MRCP methods were successfully performed in all the patients. The contrast ratio, SNR and CNR of the CBD were significantly higher for 3D-BH-CS-MRCP than those for 3D-NT-MRCP and 3D-BH-PI-MRCP images. Overall image quality did differ significantly across the three sequences. Visualization of the CBD, RHD, LHD, anterior branch, posterior branch and cystic duct was similar with the 3D-BH-CS-MRCP and 3D-BH-PI-MRCP sequences. In contrast, segment 2 or 3 branch and main pancreatic duct visualization were significantly better with 3D-BH-PI-MRCP than with 3D-BH-CS-MRCP and 3D-NT-MRCP (p < 0.001). CONCLUSIONS: Both the two breath-hold approaches were considering the time-saving advantages without deterioration of image quality. Compared with 3D-BH-CS-MRCP, 3D-BH-PI-MRCP yielded significantly better visualization of the segment 2 and 3 branch of the intrahepatic duct and performed better consistency in main pancreatic duct and common bile duct morphology.

Application of Diffusion Weighted Imaging Techniques for Differentiating Benign and Malignant Breast Lesions.

To explore the value of apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM), and diffusional kurtosis imaging (DKI) based on diffusion weighted magnetic resonance imaging (DW-MRI) in differentiating benign and malignant breast lesions. A total of 215 patients with breast lesions were prospectively collected for breast MR examination. Single exponential, IVIM, and DKI models were calculated using a series of b values. Parameters including ADC, perfusion fraction (f), tissue diffusion coefficient (D), perfusion-related incoherent microcirculation (D*), average kurtosis (MK), and average diffusivity (MD) were compared between benign and malignant lesions. ROC curves were used to analyze the optimal diagnostic threshold of each parameter, and to evaluate the diagnostic efficacy of single and combined parameters. ADC, D, MK, and MD values were significantly different between benign and malignant breast lesions (P<0.001). Among the single parameters, ADC had the highest diagnostic efficiency (sensitivity 91.45%, specificity 82.54%, accuracy 88.84%, AUC 0.915) and the best diagnostic threshold (0.983 µm2/ms). The combination of ADC and MK offered high diagnostic performance (sensitivity 90.79%, specificity 85.71%, accuracy 89.30%, AUC 0.923), but no statistically significant difference in diagnostic performance as compared with single-parameter ADC (P=0.268). The ADC, D, MK, and MD parameters have high diagnostic value in differentiating benign and malignant breast lesions, and of these individual parameters the ADC has the best diagnostic performance. Therefore, our study revealed that the use of ADC alone should be useful for differentiating between benign and malignant breast lesions, whereas the combination of MK and ADC might improve the diagnostic performance to some extent.

Ultimate conversion efficiency of second harmonic generation in all-dielectric resonators of quasi-BICs in consideration of nonlinear refraction of dielectrics.

We investigate second harmonic generation (SHG) in all-dielectric resonance nanostructures of high-Q factors assisted by quasi-bound states in the continuum (quasi-BICs). The typical resonators, e.g., guided-mode resonance gratings and asymmetric metasurfaces, fabricated by AlGaAs were numerically studied with the consideration of nonlinear refraction of AlGaAs. The resonance peak and line-shape of linear transmission and SHG spectra in the resonators can be dramatically changed under intense pump intensities. The SHG conversion efficiency in the nanostructures working at quasi-BICs is much lower than the traditionally expected values without considering the nonlinear refraction of dielectrics. The ultimate SHG conversion efficiency is finally obtained. The investigation has the significance for the design and understanding of efficient nonlinear metasurfaces of high-Q factors.

Neurite orientation dispersion and density imaging in evaluation of high-grade glioma-induced corticospinal tract injury.

PURPOSE: To evaluate the application of neurite orientation dispersion and density imaging (NODDI) to brain glioma-induced corticospinal tract (CST) injury. MATERIAL AND METHODS: Twenty-four patients with high-grade glioma (HGG) in or adjacent to the CST pathway and 12 matched healthy subjects underwent structural and diffusion MRI. The CSTs were reconstructed on the both sides. The CST features including morphological features (track number, average track length and track volume) and the diffusion parameter values including fractional anisotraphy (FA), mean diffusivity (MD), intracellular volume fraction (ICVF), isotropic or free water volume fraction (ISOVF) and orientation dispersion index (ODI) along the CST were calculated. The CST features were compared between the affected and healthy side for HGG patients and between the left and right side for healthy subjects. The relative CST features were compared across the healthy subjects, patients with motor weakness and patients with normal muscle strength. Receiver operating characteristic (ROC) curve was applied to evaluate the performance of each relative CST characteristic for HGG-induced CST changes. RESULTS: Compared with the CST features on the healthy side, the track number, track volume and FA along the CST changed significantly on the affected side for HGG patients (p < 0.05 for all), whereas MD and ICVF changed significantly on the affected side only for HGG patients with motor weakness (p = 0.012 for both). In patients with motor weakness, the relative MD was significantly higher (p < 0.001), whereas the relative FA and ICVF was significantly lower (p = 0.002 and <0.001) than those in patients with normal muscle strength. The relative ICVF had a similar area under curve (AUC) to that of MD (AUC=0.953 and 0.969). Compared with the relative CST features in the healthy subjects, only the relative ICVF was significantly lower in HGG patients with normal muscle strength (p = 0.012). CONCLUSIONS: NODDI seems to be useful in reflecting the HGG infiltration to CST, and can evaluate the CST destruction with a performance similar to DTI by providing additional information about neurite density for HGG-induced CST injury.

Hoya pyrifolia (Apocynaceae), a new species from south-western Yunnan, China.

Hoya pyrifolia, a new species of Apocynaceae from Yunnan Province, China, is described and illustrated. Results from phylogenetic analyses, based on combined DNA fragments of the nuclear ribosomal external transcribed spacer (ETS), intergeneric transcribed spacer (ITS) and three plastid DNA fragments (matK, psbA-trnH and trnT-trnL), showed that the new species was nested within a clade, including Hoya species distributed in the subtropical foothills of the Himalayas and the Tibet-Sichuan Plateau. Morphologically, the new species can be distinguished from its close relatives by its pyriform and slightly pubescent leaves, as well as the 4-flowered inflorescences.

Laplacian-Regularized Mean Apparent Propagator-MRI in Evaluating Corticospinal Tract Injury in Patients with Brain Glioma.

OBJECTIVE: To evaluate the application of laplacian-regularized mean apparent propagator (MAPL)-MRI to brain glioma-induced corticospinal tract (CST) injury. MATERIALS AND METHODS: This study included 20 patients with glioma adjacent to the CST pathway who had undergone structural and diffusion MRI. The entire CSTs of the affected and healthy sides were reconstructed, and the peritumoral CSTs were manually segmented. The morphological characteristics of the CST (track number, average length, volume, displacement of the affected CST) were examined and the diffusion parameter values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), mean squared displacement (MSD), q-space inverse variance (QIV), return-to-origin probability (RTOP), return-to-axis probabilities (RTAP), and return-to-plane probabilities (RTPP) along the entire and peritumoral CSTs, were calculated. The entire and peritumoral CST characteristics of the affected and healthy sides as well as those relative CST characteristics of the patients with motor weakness and normal motor function were compared. RESULTS: The track number, volume, MD, RD, MSD, QIV, RTAP, RTOP, and RTPP of the entire and peritumoral CSTs changed significantly for the affected side, whereas the AD and FA changed significantly only in the peritumoral CST (p < 0.05). In patients with motor weakness, the relative MSD of the entire CST, QIV of the entire and peritumoral CSTs, and the AD, MD, RD of the peritumoral CST were significantly higher, whereas the RTPP of the entire and peritumoral CSTs and the RTOP of the peritumoral CST were significantly lower than those in patients with normal motor function (p < 0.05 for all). In contrast, no significant changes were found in the CST morphological characteristics, FA, or RTAP (p > 0.05 for all). CONCLUSION: MAPL-MRI is an effective approach for evaluating microstructural changes after CST injury. Its sensitivity may improve when using the peritumoral CST features.

Association Between Small Vessel Disease Markers, Medial Temporal Lobe Atrophy and Cognitive Impairment After Stroke: A Systematic Review and Meta-Analysis.

OBJECTIVES: Two-thirds of stroke survivors suffer from cognitive impairment, and up to one-third of them progress to dementia. However, the underlying pathogenesis is complex and controversial. Recent evidence has found that cerebral small vessel disease (SVD) markers and the Alzheimer's disease (AD) neuroimaging marker medial temporal lobe atrophy (MTLA), alone or in combination, contribute to the pathogenesis of poststroke cognitive impairment (PSCI). In the present systematic review and meta-analysis, we synthesized proof for these neuroimaging risk factors among stroke patients. MATERIALS AND METHODS: PUBMED, MEDLINE, EMBASE and the Cochrane Library were searched for studies investigating imaging predictors of cognitive impairment or dementia following stroke. Meta-analysis was conducted to compute the odds ratios (ORs). RESULTS: Thirteen studies were enrolled in the present study, and only ten of them, comprising 2713 stroke patients, were eligible for inclusion in the meta-analysis. MTLA was significantly correlated with PSCI (OR = 1.97, 95% CI: 1.48-2.62, I2 = 0.0%). In addition, white matter hyperintensities (WMH), as a neuroimaging marker of SVD, were associated with PSCI (OR = 1.17, 95% CI: 1.12-1.22, I2 = 0.0%). However, the presence of lacunar infarcts and enlarged perivascular spaces (EPVS) were not associated with the risk of PSCI. CONCLUSIONS: The findings of the present study suggest that MTLA and WMH were associated with an increased risk of PSCI.