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1.
Eur Radiol ; 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33884473

RESUMO

OBJECTIVES: To investigate whether amide proton transfer-weighted imaging (APTWI) and diffusion kurtosis imaging (DKI) can be used to evaluate endometrial carcinoma (EC) in terms of clinical type, histological grade, subtype, and Ki-67 index. METHODS: Eighty-eight patients with EC underwent pelvic DKI and APTWI. The non-Gaussian diffusion coefficient (Dapp), apparent kurtosis coefficient (Kapp), and magnetization transfer ratio asymmetry (MTRasym (3.5 ppm)) were calculated and compared based on the clinical type (type I, II), histological grade (high- and low-grade), and subtype (endometrioid adenocarcinoma (EA) and non-EA). Correlation coefficients were calculated for each parameter with histological grades and the Ki-67 index. RESULTS: The MTRasym (3.5 ppm) and Kapp values were higher in the type II group and high-grade group than in the type I and low-grade groups, respectively, while the Dapp values were lower in the type I and low-grade groups, respectively (all p < 0.05). The Kapp value was higher in the EA group than in the non-EA group (p = 0.022). The Kapp value was the only independent predictor for the histological grade of EA and the clinical type of EC. The AUC (DKI) was higher than the AUC (APTWI) in the identification of type I and II EC and high- and low-grade EA (Z = 2.042, 2.013, p = 0.041, 0.044), while in the identification of EA and non-EA, only the difference in Kapp was statistically significant. Moreover, the Kapp and MTRasym (3.5 ppm) values and Dapp values correlated positively and negatively, respectively, with histological grade (r = 0.759, 0.555, 0.624, and 0.462, all p < 0.05) and Ki-67 index (r = -0.704, -0.507, all p < 0.05). CONCLUSION: Both DKI- and APTWI-related parameters have potential as imaging markers in estimating the histological features of EC, while DKI shows better performance than APTWI in this study. KEY POINTS: • DKI and APTWI can be used to preliminarily evaluate the histological characteristics of endometrial carcinoma (EC). • The Kapp was the only independent predictor for the histological grade of EA and the clinical type of EC. • The Kapp, MTRasym (3.5 ppm), and Dapp correlated positively and negatively, respectively, with histological grade and Ki-67 index.

2.
Appetite ; 164: 105261, 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33894301

RESUMO

OBJECTIVES: Dieting is a cognitively taxing task that does not always advance well-being. A dieting lapse may result in overconsumption that undermines long-term health goals. This research explores how a process known as counterfactual thinking (CFT), reliving an event to figure out where things went wrong, may help consumers faced with a temptation to indulge. Consumers who engage in upward CFT generate an alternative set of steps or actions that could have changed the outcome in a situation. We investigate if and how CFT may be used strategically to help consumers stick to their dieting goal and advance their own well-being. METHODS: A 2 (CFT vs. control) x 2 (dieter vs. non-dieter) between-subjects factorial design was used to evaluate participant interest in a digital health tracking tool after viewing an advertisement (Study 1). Study 2 was conducted as a follow-up to measure their use of the digital tracking tool, intentions to continue to use, and calories consumed (as tracked in the system) after a two-week period using the digital tracking tool advertised in Study 1. RESULTS: We find that engaging in upward CFT increases a dieter's intentions to track their food, a practice emerging as a strategy to help maintain goal consistency. Among dieters, perceived feasibility mediated the impact of CFT on both ad evaluations (Study 1) as well as intentions to continue to use the digital health tracking tool (Study 2). In the follow-up study we also find that dieters in the CFT condition used more of the online features offered and that all consumers in the CFT condition ate marginally fewer calories across two weeks of tracking using the digital health tool. DISCUSSION: Encouraging consumers to generate upward counterfactual thoughts in the face of a dieting lapse increases their propensity to use an online tracking tool and reduces calories consumed. In the age of digital tracking tools, personalized prompts could be set to encourage CFT to help get a consumer back on track to pursue their healthy eating goals.

3.
J Neurochem ; 2021 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-33774813

RESUMO

Stroke is a major cause of vascular cognitive dysfunction, such as memory impairment. We aimed to explore the neural substrates underlying verbal memory impairment in subcortical stroke patients by the methods of voxel-wise cerebral blood flow (CBF) and the functional covariance network (FCN). Sixty patients with chronic subcortical stroke and sixty normal controls (NCs) were recruited into this study. We used three-dimensional pseudo-continuous arterial spin-labeling imaging to measure alterations in CBF and FCNs. We mapped the overall CBF alterations in a voxel-wise manner and compared CBF measurements using a two-sample t-test. Correlations between CBF and verbal memory were also investigated. Subsequently, we constructed FCNs by calculating the correlation between specific regions and all other voxels of a whole brain, separately within the two groups. Thereafter, by comparing differences of the FCN patterns between the patient and NC groups, we investigated the connection alterations within the FCN maps. The stroke patients showed verbal short-term memory (VSTM) deficits compared to NCs. The patients exhibited decreased CBF in the ipsilesional insula and ventral sensorimotor network, and increased CBF in contralesional frontal cortical and subcortical regions (putamen, and thalamus). Meanwhile, the CBF in the ipsilesional insula was positively correlated, and the contralesional frontal cortical was negativity correlated, with VSTM scores. Moreover, we found that stroke patients exhibited disordered connection within FCNs compared to NCs. The study suggests that the underlying imaging biomarker of VSTM impairment in patients with subcortical stroke was associated with disconnection of the frontal lobe network.

4.
J Phys Chem Lett ; : 1904-1910, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33591752

RESUMO

The fully inorganic perovskite lead cesium bromide single crystal (CsPbBr3 SC) is considered as an excellent candidate semiconductor for photodetectors because of its superior humidity resistance, thermal stability, and light stability compared with organic-inorganic hybrid perovskites as well as its photoelectric properties such as large light absorption coefficient and ultralong carrier migration distance. In this Letter, we utilize the inverse temperature solubility of CsPbBr3 in ternary solvents to grow large-sized CsPbBr3 SCs. By the use of the (101) plane, CsPbBr3 SC-based photodetectors are fabricated, which exhibit excellent polarized light response characteristics. The photocurrent relies on the polarization angle in a sinusoidal fashion and shows strong anisotropic optoelectronic properties. The photodetection performance perpendicular to the y axis is significantly higher than that parallel to the y axis, and the dichroic ratio under 405 nm illumination at a bias voltage of 1 V reaches 2.65. The experimental results are consistent with the results of first-principles calculations.

5.
Nature ; 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33239786

RESUMO

Choosing a mate is one of the most consequential decisions a female will make during her lifetime. A female fly signals her willingness to mate by opening her vaginal plates, allowing a courting male to copulate1,2. Vaginal plate opening (VPO) occurs in response to the male courtship song and is dependent on the mating status of the female. How these exteroceptive (song) and interoceptive (mating status) inputs are integrated to regulate VPO remains unknown. Here we characterize the neural circuitry that implements mating decisions in the brain of female Drosophila melanogaster. We show that VPO is controlled by a pair of female-specific descending neurons (vpoDNs). The vpoDNs receive excitatory input from auditory neurons (vpoENs), which are tuned to specific features of the D. melanogaster song, and from pC1 neurons, which encode the mating status of the female3,4. The song responses of vpoDNs, but not vpoENs, are attenuated upon mating, accounting for the reduced receptivity of mated females. This modulation is mediated by pC1 neurons. The vpoDNs thus directly integrate the external and internal signals that control the mating decisions of Drosophila females.

6.
Front Oncol ; 10: 562049, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33194630

RESUMO

Background: Preoperative grading of hepatocellular carcinoma (HCC) is an important factor associated with prognosis after liver resection. The promising prediction of the differentiation of HCC remains a challenge. The purpose of our study was to investigate the value of amide proton transfer (APT) imaging in predicting the histological grade of HCC, compared with the intravoxel incoherent motion (IVIM) imaging. Methods: From September 2018 to February 2020, 88 patients with HCC were enrolled and divided into four groups (G1, G2, G3, and G4) based on the histologic grades. Preoperative APT signal intensity (SI), apparent diffusion coefficient (ADC), true molecular diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f ) of HCC were independently measured by two radiologists. The averaged values of those parameters were compared using an analysis of variance. The Spearman rank analysis was used to compare the correlation between those imaging parameters and the histological grades. Receiver operating characteristic (ROC) curve analysis was used to explore the predictive performance. Results: There were significant differences in APT SI, ADC, D, and f among the four grades of HCC (all P < 0.001). A moderate to good relationship was found between APT SI and the histologic grade of HCC (r = 0.679, P < 0.001). APT SI had an area under the ROC curve (AUC) of 0.890 (95% CI: 0.805-0.947) for differentiating low- from high-grade HCC, and the corresponding sensitivity and specificity were 85.71% and 82.05%, respectively. Comparison of ROC curves demonstrated that the AUC of APT SI was significantly higher than those of IVIM-derived parameter (Z = 2.603, P = 0.0092; Z = 2.099, P = 0.0358; Z = 4.023, P = 0.0001; Z = 2.435, P = 0.0149, compared with ADC, D, D*, and f , respectively). Moreover, the combination of both techniques further improved the diagnostic performance, with an AUC of 0.929 (95% CI: 0.854-0.973). Conclusion: APT imaging may be a potential noninvasive biomarker for the prediction of histologic grading of HCC and complements IVIM imaging for the more accurate and comprehensive characterization of HCC.

7.
Dis Aquat Organ ; 142: 13-21, 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33150871

RESUMO

Nocardia seriolae is the causative agent of nocardiosis in both marine and freshwater fish. Here, we report on multiple outbreaks of nocardiosis associated with elevated mortality (23-35%) in farmed largemouth bass in Sichuan, China, from 2017 to 2018. A total of 9 strains isolated from diseased largemouth bass were identified as N. seriolae by phenotypic characterization, 16S rRNA and hsp65 gene sequence analysis. The clinical signs of infected largemouth bass included hemorrhage, skin ulcers and prominent tubercles varying in size in the gill, liver, spleen and kidney. Experimental infection indicated that these isolates were the pathogens responsible for the mortalities. In vitro antibacterial activities of 12 antibiotics against N. seriolae isolates were determined as minimum inhibitory concentrations. Histopathological observation of diseased fish infected with N. seriolae showed necrotizing granulomatous hepatitis, nephritis, splenitis, epithelial hypertrophy and hyperplasia with degenerative changes of the epithelium in the gill. Large quantities of bacterial aggregates were found in the necrotic area of the granuloma by Lillie-Twort Gram stain and immunocytochemistry. Our findings indicated that N. seriolae is a serious threat to the largemouth bass Micropterus salmoides industry in Southwest China.


Assuntos
Bass , Doenças dos Peixes , Nocardia , Animais , China/epidemiologia , Doenças dos Peixes/epidemiologia , Nocardia/genética , Filogenia , RNA Ribossômico 16S/genética
8.
Artigo em Inglês | MEDLINE | ID: mdl-33009849

RESUMO

AIM: The aim of this study was to assess the whole-brain dynamic functional connectivity of first-episode and treatment-naive patients with obsessive-compulsive disorder (OCD) and to investigate the clinical correlations of abnormal changes in dynamic functional connectivity. METHODS: Twenty-nine patients in our hospital diagnosed with first-episode OCD and 29 healthy controls matched for age, sex, and education were included in our study. Resting-state functional magnetic resonance imaging scans were performed on a 3.0-Tesla magnetic resonance scanner in our hospital. Three temporal metrics of connectivity state expression were calculated: (i) fraction of time; (ii) mean dwell time; and (iii) number of transitions. The Yale-Brown Obsessive-Compulsive Scale was used to assess the severity of OCD symptoms. RESULTS: In the comparison of dynamic functional connectivity indicators, we found that there were significant differences in the number of transitions among the four functional connectivity states but no significant differences in the fraction of time or the mean dwell time. The total Yale-Brown Obsessive-Compulsive Scale score was positively correlated with the number of transitions. In the validation analysis, when the size of the sliding window changed, there was still a significant difference in the number of transitions between OCD patients and healthy controls. CONCLUSION: The functional networks of OCD patients have lost the correct dynamic rhythm, which may be considered as a potential marker for OCD and for new directions for its intervention.

9.
Abdom Radiol (NY) ; 2020 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-33074424

RESUMO

PURPOSE: To assess the value of various diffusion parameters obtained from monoexponential, biexponential, and stretched-exponential diffusion-weighted imaging (DWI) models for staging hepatic fibrosis (HF) and grading inflammatory activity in patients with chronic hepatitis B (CHB). METHODS: 82 patients with CHB and 30 healthy volunteers underwent DWI with 13 b-values on a 3T MRI unit. The standard apparent diffusion coefficient (ADCst) was calculated using a monoexponential model. The true diffusion coefficient (Dt), pseudo-diffusion coefficient (Dp), and perfusion fraction (f) were calculated using a biexponential model. The distributed diffusion coefficient (DDC) and water-molecule diffusion heterogeneity index (α) were calculated using a stretched-exponential model. Receiver operating characteristic (ROC) curves were performed for diffusion parameters to compare the diagnosis performance. RESULTS: The distributions of hepatic fibrosis stages and the inflammatory activity grades (METAVIR scoring system) were as follows: F0, n = 1; F1, n = 16; F2, n = 31; F3, n = 19; and F4, n = 15. A0, n = 1; A1, n = 14; A2, n = 46; and A3, n = 21. ADCst, Dt and DDC values showed negative correlation with the fibrosis stage (r = - 0.418, - 0.717 and - 0.630, all P < 0.001) and the inflammatory activity grade (r = - 0.514, - 0.626 and - 0.550, all P < 0.001). The area under the ROC curve (AUC) of Dt (AUC = 0.854, 0.881) and DDC (AUC = 0.794, 0.834) were significantly higher than that of ADCst (AUC = 0.637, 0.717) in discriminating significant fibrosis (≥ F2) and advanced fibrosis (≥ F3) (all P < 0.05). Although Dt (AUC = 0.867, 0.836) and DDC (AUC = 0.810, 0.808) showed higher AUCs than ADCst (AUC = 0.767, 0.803), there was no significant difference in their ability in detecting inflammatory activity grade ≥ A2/A3 (P > 0.05). CONCLUSIONS: Dt and DDC are promising indicators and outperform ADCst for staging HF. While both Dt and DDC have similar diagnostic performance compared with ADCst for grading inflammatory activity.

10.
Eur Radiol ; 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32888071

RESUMO

OBJECTIVES: To compare the value of amide proton transfer-weighted imaging (APTWI) and diffusion kurtosis imaging (DKI) in differentiating benign and malignant breast lesions and analyze the correlations between the derived parameters and prognostic factors of breast cancer. METHODS: One hundred thirty-five women underwent breast APTWI and DKI. The magnetization transfer ratio asymmetry (MTRasym (3.5 ppm)), apparent kurtosis coefficient (Kapp), and non-Gaussian diffusion coefficient (Dapp) were calculated according to the histological subtype, grade, and prognostic factors (Ki-67, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), lymph node metastasis, and maximum lesion diameter). The differences, efficacy, and correlation between the parameters were determined. RESULTS: The Kapp value was higher and the Dapp and MTRasym (3.5 ppm) values were lower in the malignant group than in the benign group (all p < 0.001; AUC (Kapp) = 0.913, AUC (Dapp) = 0.910, and AUC (MTRasym (3.5 ppm)) = 0.796). The differences in the AUC between Kapp and MTRasym (3.5 ppm) and between Dapp and MTRasym (3.5 ppm) were significant (p = 0.023, 0.046). Kapp was moderately correlated with the pathological grade (|r| = 0.724) and mildly correlated with Ki-67 and HER-2 expression (|r| = 0.454, 0.333). Dapp was moderately correlated with the pathological grade (|r| = 0.648) and mildly correlated with Ki-67 expression (|r| = 0.400). MTRasym (3.5 ppm) was only mildly correlated with the pathological grade (|r| = 0.468). CONCLUSION: DKI is superior to APTWI in differentiating between benign and malignant breast lesions. Each parameter is correlated with some prognostic factors to a certain extent. KEY POINTS: • DKI and APTWI provide valuable information regarding lesion characterization. • Kapp, Dapp, and MTRasym (3.5 ppm) are valid parameters for the characterization of tissue microstructure. • DKI is superior to APTWI in the study of breast cancer.

11.
Neuroscience ; 448: 255-265, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-32890665

RESUMO

Our aim was to identify the longitudinal changes in gray matter volume (GMV) and secondary alterations of structural covariance after pontine stroke (PS). Structural MRI and behavioral scores were obtained at 1 week, 1 month, 3 months, 6 months in 11 patients with PS. Twenty healthy subjects underwent the same examination only once. We used voxel-based morphometry and seed-based structural covariance to investigate the altered GMV and structural covariance patterns. Furthermore, the associations between the GMV changes and behavioral scores were assessed. With the progression of the disease, GMV decreased significantly in the bilateral cerebellar posterior lobe (ipsilateral Crus II (CBE Crus II_IL) and contralateral Crus I (CBE Crus I_CL)), which were initially detected at the first month and then continued to decrease during the following 6 months. Based on the CBE Crus II_IL and CBE Crus I_CL as seed regions, structural covariance analysis revealed that there were more positively and negatively correlated brain regions in PS group, mainly distributed in the bilateral prefrontal lobe, parietal lobe, temporal lobe, paralimbic system and cerebellum. In addition, PS group showed more additional correlations between these covariant brain regions, and the changes of GMV in these regions were correlated with behavioral scores related to motor and cognitive functions. These findings indicate that PS could lead to significant GMV atrophy in the bilateral cerebellar posterior lobe at the early stage, accompanied by anomalous structural covariance patterns with more covariant brain regions and additional structural connectivity, which may provide useful information for understanding the neurobiological mechanisms of behavioral recovery after PS.

12.
Curr Biol ; 30(19): 3749-3760.e3, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32795445

RESUMO

The mating decisions of Drosophila melanogaster females are primarily revealed through either of two discrete actions: opening of the vaginal plates to allow copulation, or extrusion of the ovipositor to reject the male. Both actions are triggered by the male courtship song, and both are dependent upon the female's mating status. Virgin females are more likely to open their vaginal plates in response to song; mated females are more likely to extrude their ovipositor. Here, we examine the neural cause and behavioral consequence of ovipositor extrusion. We show that the DNp13 descending neurons act as command-type neurons for ovipositor extrusion, and that ovipositor extrusion is an effective deterrent only when performed by females that have previously mated. The DNp13 neurons respond to male song via direct synaptic input from the pC2l auditory neurons. Mating status does not modulate the song responses of DNp13 neurons, but rather how effectively they can engage the motor circuits for ovipositor extrusion. We present evidence that mating status information is mediated by ppk+ sensory neurons in the uterus, which are activated upon ovulation. Vaginal plate opening and ovipositor extrusion are thus controlled by anatomically and functionally distinct circuits, highlighting the diversity of neural decision-making circuits even in the context of closely related behaviors with shared exteroceptive and interoceptive inputs.

13.
Oncol Lett ; 20(2): 1597-1606, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32724401

RESUMO

Our previous study reported a method of using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to analyze the association between abnormal fucosylation of serum glycoproteins and the progression of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). In the present study, the aforementioned method was improved by focusing on fucosylated glycoproteins <10 kD, classification models were established and blind tests were performed on an enlarged sample size (n=299). According to the present results, the classification models had a sensitivity and specificity of 74.31 and 76.32%, respectively, to identify HCC among all serum samples, 81.65 and 83.08%, respectively, to distinguish HCC from HBV-associated cirrhosis and chronic hepatitis Band 88.99 and 84.62%, respectively, to distinguish HCC from HBV-associated cirrhosis. When combined with α-fetoprotein (AFP) measurements (AFP >20 ng/ml), the sensitivity and specificity of the models were significantly elevated to 80.73 and 87.37%, 87.16 and 90.00%, and 92.66 and 93.84%, respectively. In addition, the HBV-HCC vs. HBV-cirrhosis classification model was used to analyze serum samples collected from 9 patients with cirrhosis 1 year before they were diagnosed with HCC, and from 6 patients who had cirrhosis but developed no signs of HCC for the following 3 years. The model identified 7 patients (77.78%) with no significant clinical symptoms of HCC, and gave no false positive results, demonstrating that the classification models established in the present study may be useful for the early diagnosis of HCC. After isolation and purification, two proteins with differential expression were identified as isoform 1 of inter-α-trypsin inhibitor heavy chain 4 precursor, and thymosin ß-4-like protein 3. These may be used as candidate markers for HCC diagnosis. Additionally, the present study indicates that defucosylation of serum glycoproteins may occur during the development and progression of HCC.

14.
Sci Rep ; 10(1): 12324, 2020 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-32704000

RESUMO

It has been shown that bamboo leaf flavone (BLF) displays biological and pharmacological activities in mammals. However, the effects of BLF on broiler gut microbiota and related immune function have not been investigated. The aim of this study was to test our hypothesis that BLF can improve the health status of broilers by modulating the gut microbiota. A total of 300 one-day-old Arbor Acres (AA) broilers were used to characterize their gut microbiota and immune status after feeding diet supplemented with BLF. The V4 hypervariable region of the 16S rRNA gene from cecal bacteria was sequenced via the Illumina MiSeq platform. The Immune status and related parameters were assessed, including the immune organ index (the spleen, thymus, and bursa), serum concentrations of IL-2 and INF-γ, and spleen IL-2 and INF-γ gene expressions. The results showed the BLF diet had an Immune enhancement effect on broilers. In addition, BFL caused the changes of the gut microbial community structure, resulting in greater proportions of bacterial taxa belonging to Lactobacillus, Clostridiales, Ruminococcus, and Lachnospiraceae. These bacteria have been used as probiotics for producing short chain fatty acids in hosts. These results indicate that BLF supplement improves immune function in chicken via modulation of the gut microbiota.

15.
Fish Shellfish Immunol ; 104: 654-662, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32561456

RESUMO

In aquaculture, the incidence of enteritis due to Streptococcus iniae infection in Siberian sturgeon (Acipenser baerii) has increased in recent years. The pathogenesis of S. iniae is largely unknown due to the paucity of experimental studies on fish intestinal inflammation. In this study, S. iniae infection of A. baerii juveniles was induced by anal intubation of 0.15 mL at a low lethal dose (2 × 107 CFU/mL). Intestinal pathology and gene expression studies were conducted within 10 days of the experiment. Histopathological examination showed severe intestinal lesions, inflammatory cell infiltration, intestinal submucosa edema, epithelial cell shedding and necrosis. Predominant symptoms of exudative inflammation, metamorphic inflammation and proliferative inflammation on days 1-3, 4-6, and 7-10 post infection were shown, respectively. Ultrastructural observations also revealed fractured microvilli and shedding on days 4-6. Intestinal villi gradually repaired during the subsequent 7-10 days post infection. Expression of the pro-inflammatory cytokines, tumor necrosis factor and interleukin 1ß were up-regulated on days 1-3 followed by a significant decrease on day 5, ultimately reaching control levels on day 10 post infection. A similar pattern was shown in mucus cells, involving mucin secretion and expression of the mucin encoding gene, Mucin-2. These results showed the cellular response to S. iniae infection associated with inflammatory genes expression in the Siberian sturgeon.

16.
Phys Chem Chem Phys ; 22(25): 14276-14283, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32555919

RESUMO

Zero-dimensional (0D) inorganic perovskites, particularly Cs4PbBr6, have been attracting wide attention due to their excellent photoluminescence (PL) efficiency and spectral color purity. The PL origin of Cs4PbBr6 and the underlying photophysics, however, draw intense debate and remain controversial. Revealing the photo-excited carrier generation, separation, and recombination, as well as the roles that mobile ions play, is crucial and helpful to deeply understand the photo-physical property. Photoconductivity is one of the effective approaches to closely explore the photophysics. In this study, high-purity Cs4PbBr6 single crystals were grown from Cs-enriched solutions. Negative photoconductivity was first observed in Cs4PbBr6 through Au-crystal-Au photo-detectors, and the photocurrents under high illumination power are similar to those of the diode. It is considered that the built-in electric field produced by the charged excitons combined by the neutral excitons and vacancies of Br (VBr+) are responsible for the eccentric negative photoconductivity phenomena because of strong Coulomb interactions and low VBr+ formation energy in Cs4PbBr6.

17.
Skeletal Radiol ; 49(10): 1597-1606, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32382978

RESUMO

OBJECTIVE: To investigate the diagnostic values of T2 mapping and diffusion-weighted imaging (DWI) for active sacroiliitis in ankylosing spondylitis (AS) and to evaluate the correlations of T2 and ADC values with Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Spondyloarthritis Research Consortium of Canada (SPARCC) scores. METHODS: A total of 77 AS patients with sacroiliitis and 45 healthy controls were enrolled. All patients were scanned by standard magnetic resonance imaging longitudinal relaxation time (T1)-weighted imaging (T1WI), fat-saturated T2-weighted imaging (FS-T2WI)] and DWI, and T2 mapping of the sacroiliac joints. According to whether subchondral bone marrow edema was present in the FS-T2WI sequence, the 77 patients were divided into an active group (41 cases) and an inactive group (36 cases). The T2 and apparent diffusion coefficient (ADC) values of the subchondral bone marrow were measured in the active group, the inactive group, and the healthy control group. The average T2 and ADC values were compared among the three groups. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic efficacy of T2 and ADC values for sacroiliitis. The correlations of T2 and ADC values with the BASDAI score and the SPARCC score were analyzed. RESULTS: The T2 and ADC values in the active group were higher than those in the inactive group, while that in the inactive group were significantly higher than those in the healthy control group (p < 0.0001). The T2 and ADC values of the AS patients were positively correlated with BASDAI scores, and the correlation coefficients (r) were 0.786 (p < 0.0001) and 0.842 (p < 0.0001), respectively. The areas under the ROC curves (AUCs) of T2 and ADC values between the active and inactive groups, the active group and the healthy control group, and the inactive group and the healthy control group were 0.889 (95% CI, 0.80-0.95) and 0.917 (95% CI, 0.83-0.97), 0.982 (95% CI, 0.93-1.00) and 0.984 (95% CI, 0.93-1.00), and 0.628 (95% CI, 0.51-0.73) and 0.871 (95% CI, 0.78-0.94), respectively. The T2 and ADC values of the AS patients in the active group were positively correlated with SPARCC scores, and the correlation coefficients (r) were 0.757 (p < 0.0001) and 0.764 (p < 0.0001), respectively. CONCLUSION: T2 and ADC values can be used to quantitatively assess the activity of AS, and the efficacy of the ADC value in the diagnosis of AS was higher than that of the T2 value.

18.
Eur Radiol ; 30(10): 5758-5767, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32424593

RESUMO

OBJECTIVES: To analyze the value of amide proton transfer-weighted imaging (APTWI) and diffusion kurtosis imaging (DKI) in differentiating cervical cancer (CC) pathological type, grade, and stage. METHODS: One hundred and twelve women underwent pelvic APTWI and DKI. The magnetization transfer ratio asymmetry (MTRasym, 3.5 ppm), apparent kurtosis coefficient (Kapp), and non-Gaussian diffusion coefficient (Dapp) were calculated by histological subtype, grade, and stage. The differences, efficacy, and correlation between parameters were determined. RESULTS: The MTRasym(3.5 ppm) and Dapp values of the adenocarcinoma (CA) group were higher than those of the cervical squamous carcinoma (CSC) group, while the Kapp values were lower than those of the CSC group. The MTRasym(3.5 ppm) and Kapp values of the high-grade group were higher than those of the low-grade group, while the Dapp values were lower than those of the low-grade group. The Dapp values of the advanced-stage group were lower than those of the early-stage group, while the Kapp values were greater than those of the early-stage group. The Kapp showed the highest efficacy in differentiating CSC and CA, high- and low-grade CC, and advanced- and early-stage CC. In the CSC and CA groups, both the Kapp and Dapp were highly correlated with pathological grade, and the MTRasym(3.5 ppm) was weakly correlated with pathological grade. The Kapp, Dapp, and MTRasym(3.5 ppm) were all weakly correlated with pathological stage. CONCLUSION: Both DKI and APTWI can be used in preliminary evaluations of CC, but DKI has advantages in the identification of pathological type, grade, and stage. KEY POINTS: • PTWI and DKI provide new information regarding cervical cancer. • MTRasym(3.5 ppm), Dapp, and Kapp are valid parameters to characterize tissue microstructure. • DKI is superior to APTWI in the study of cervical cancer.

19.
J Magn Reson Imaging ; 52(6): 1657-1667, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32424881

RESUMO

BACKGROUND: The outcome of intermediate-stage hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE) is greatly heterogeneous. Current means for predicting HCC response to TACE are lacking. PURPOSE: To investigate whether the combination of parameters derived from amide proton transfer (APT) and intravoxel incoherent motion (IVIM) imaging, and morphological characteristics of tumor can establish a better prediction model than the univariant model for HCC response to TACE. STUDY TYPE: Prospective. SUBJECTS: 56 patients with intermediate-stage HCC (50 males and six females). FIELD STRENGTH/SEQUENCES: 3.0T; T2 -weighted-fast spin echo, 3D liver acquisition with volume flex, single-shot fast spin echo-planar imaging (EPI), spin echo-EPI. ASSESSMENT: Pretreatment APT signal intensities (SIs), apparent diffusion coefficient (ADC), true molecular diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) for tumor, peritumoral, and normal tissues were measured. Follow-up MRI scanning was performed, and the patients were classified as responders or nonresponders based on the modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. STATISTICAL TESTS: The imaging parameters were compared among the three tissues and between the two groups using analysis of variance (ANOVA) or two-sample t-test. The prediction model's variables were derived from univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curve analysis was used to explore the predictive performance. RESULTS: Based on the logistic regression analysis results, we established a prediction model that integrated the APT SI and D values in the tumor tissue and the tumor size. ROC analyses revealed that the model was better able to predict tumor response to TACE (area under the ROC curve = 0.851) than the individual parameters on their own. DATA CONCLUSION: A prediction model incorporating pretreatment APT SI, D in the tumor tissue and tumor size may be useful for predicting the response of intermediate-stage HCC to TACE. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 1 J. MAGN. RESON. IMAGING 2020;52:1657-1667.

20.
J Magn Reson Imaging ; 52(4): 1175-1186, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32369256

RESUMO

BACKGROUND: Amide proton transfer-weighted imaging (APTWI) and intravoxel incoherent motion imaging (IVIM) are valuable MRI techniques applied to cancer. PURPOSE: To compare APTWI and IVIM in the diagnosis of benign and malignant breast lesions and to evaluate the correlations between different parameters (MTRasym [3.5 ppm], D, D*, and f) and prognostic factors for breast cancer. STUDY TYPE: Retrospective. POPULATION: In all, 123 breast lesions were studied before treatment, including 58 benign lesions and 65 malignant lesions. FIELD STRENGTH/SEQUENCE: Conventional MRI (T1 WI, T2 WI, and diffusion-weighted imaging [DWI]), APTWI, and IVIM MRI at 3T. ASSESSMENT: The magnetization transfer ratio asymmetry at 3.5 ppm (MTRasym [3.5 ppm]), diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) values were compared between the benign and malignant groups and between groups with different expression levels of prognostic factors. STATISTICAL TESTS: Individual sample t-test, χ2 test, Spearman correlation, logistic regression, and the Delong test. RESULTS: The D and MTRasym (3.5 ppm) values of the malignant group were lower than those of the benign group; however, D* and f values were higher than those of the benign group (all P < 0.05). The areas under the curve (AUCs) of D, MTRasym (3.5 ppm), D*, and f were 0.809, 0.778, 0.670, and 0.766, respectively; however, only the difference between AUC (D) and AUC (D*) was significant (Z = 2.374, P < 0.05). The D value showed a low correlation with the pathological grade and Ki-67 expression (| r | = 0.294, 0.367); the f value showed a low correlation with estrogen receptor (ER) expression (| r | = 0.382); and the MTRasym (3.5 ppm) value showed a low correlation with pathological grade (| r | = 0.371). DATA CONCLUSION: This analysis revealed that both IVIM and APTWI could be used for the differential diagnosis of benign and malignant breast lesions, and APTWI-derived MTRasym (3.5 ppm), IVIM-derived D, D*, and f values showed correlations with some prognostic factors for breast cancer. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:1175-1186.

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