Genome-wide identification of the ICS family genes and its role in resistance to Plasmodiophora brassicae in Brassica napus L.

The isochorismate synthase (ICS) proteins are essential regulators of salicylic acid (SA) synthesis, which has been reported to regulate resistance to biotic and abiotic stresses in plants. Clubroot caused by Plasmodiophora brassicae is a common disease that threatens the yield and quality of Oilseed rape (Brassica napus L.). Exogenous application of salicylic acid reduced the incidence of clubroot in oilseed rape. However, the potential importance of the ICS genes family in B. napus and its diploid progenitors has been unclear. Here, we identified 16, 9, and 10 ICS genes in the allotetraploid B. napus, diploid ancestor Brassica rapa and Brassica oleracea, respectively. These ICS genes were classified into three subfamilies (I-III), and member of the same subfamilies showed relatively conserved gene structures, motifs, and protein domains. Furthermore, many hormone-response and stress-related promoter cis-acting elements were observed in the BnaICS genes. Exogenous application of SA delayed the growth of clubroot galls, and the expression of BnaICS genes was significantly different compared to the control groups. Protein-protein interaction analysis identified 58 proteins involved in the regulation of ICS in response to P. brassicae in B. napus. These results provide new clues for understanding the resistance mechanism to P. brassicae.

Root system architecture change in response to waterlogging stress in a 448 global collection of rapeseeds (Brassica napus L.).

MAIN CONCLUSIONS: A novel image-based screening method for precisely identifying genotypic variations in rapeseed RSA under waterlogging stress was developed. Five key root traits were confirmed as good indicators of waterlogging and might be employed in breeding, particularly when using the MFVW approach. Waterlogging is a vital environmental factor that has detrimental effects on the growth and development of rapeseed (Brassica napus L.). Plant roots suffer from hypoxia under waterlogging, which ultimately confers yield penalty. Therefore, it is crucially important to understand the genetic variation of root system architecture (RSA) in response to waterlogging stress to guide the selection of new tolerant cultivars with favorable roots. This research was conducted to investigate RSA traits using image-based screening techniques to better understand how RSA changes over time during waterlogging at the seedling stage. First, we performed a t-test by comparing the relative root trait value between four tolerant and four sensitive accessions. The most important root characteristics associated with waterlogging tolerance at 12 h are total root length (TRL), total root surface area (TRSA), total root volume (TRV), total number of tips (TNT), and total number of forks (TNF). The root structures of 448 rapeseed accessions with or without waterlogging showed notable genetic diversity, and all traits were generally restrained under waterlogging conditions, except for the total root average diameter. Additionally, according to the evaluation and integration analysis of 448 accessions, we identified that five traits, TRL, TRSA, TRV, TNT, and TNF, were the most reliable traits for screening waterlogging-tolerant accessions. Using analysis of the membership function value (MFVW) and D-value of the five selected traits, 25 extremely waterlogging-tolerant materials were screened out. Waterlogging significantly reduced RSA, inhibiting root growth compared to the control. Additionally, waterlogging increased lipid peroxidation, accompanied by a decrease in the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). This study effectively improves our understanding of the response of RSA to waterlogging. The image-based screening method developed in this study provides a new scientific guidance for quickly examining the basic RSA changes and precisely predicting waterlogging-tolerant rapeseed germplasms, thus expanding the genetic diversity of waterlogging-tolerant rapeseed germplasm available for breeding.

Metal-Free Selective Synthesis of α,ß-Unsaturated Aldehydes from Alkenes and Formaldehyde Catalyzed by Dimethylamine.

α,ß-Unsaturated aldehydes are important building blocks for the synthesis of a wide range of chemicals, including polymers. The synthesis of these molecules from cheap feedstocks such as alkenes remains a scientific challenge, mainly due to the low reactivity of alkenes. Here we report a selective and metal-free access to α,ß-unsaturated aldehydes from alkenes with formaldehyde. This reaction is catalyzed by dimethylamine and affords α,ß-unsaturated aldehydes in yields of up to 80 %. By combining Density Functional Theory (DFT) calculations and experiments, we elucidate the reaction mechanism which is based on a cascade of hydride transfer, hydrolysis and aldolization reactions. The reaction can be performed under very mild conditions (30-50 °C), in a theoretically 100 % carbon-economical fashion, with water as the only by-product. The reaction was successfully applied to non-activated linear 1-alkenes, thus opening an access to industrially relevant α,ß-unsaturated aldehydes from cheap and widely abundant chemicals at large scale.

Heat transfer analysis of generalized second-grade fluid with exponential heating and thermal heat flux.

The aim of present work is to apply the Caputo-Fabrizio fractional derivative in the constitutive equations of heat transfer. Natural convection flow of an unsteady second grade fluid over a vertical plate with exponential heating is discussed. The generalized Fourier law is substituted in temperature profile. A portion of the dimensionless factors are utilized to make the governing equations into dimensionless structures. The solutions for temperature and velocity profiles of Caputo-Fabrizio model are acquired through the Laplace transform method. These solutions are greatly affected through the variation of different dimensionless variables like Prandtl number, Grashof number, and second-grade fluid parameter. Finally, the influence of embedded parameters is shown by plotting graphs through Mathcad. From the graphical results it is concluded that, the temperature of the fluid decreases with the increasing values of the Prandtl number and Second grade fluid parameter and increases with the passage of time. The velocity of the fluid increases with increasing values of the Grashof number, second grade parameter and time while decreases with increasing values of fractional parameter and Prandtl number.

Cobalt-based MOF nanoribbons with abundant O/N species for cycloaddition of carbon dioxide to epoxides.

Chemical fixation of CO2 with epoxides is an effective option to achieve sustainable synthesis of cyclic organic carbonates. Although metal-organic frameworks (MOFs) are promising catalysts for this reaction, their low stability in aqueous solutions makes this application infeasible. In an effort to overcome this limitation, cobalt-based metal-organic framework (Co(II)MOF) nanoribbons have been prepared by coordinating the Co(II) ions with a new ligand (C16H12N4O4) full of oxygen and nitrogen moieties. Strong chemical interactions occur between the adsorbed CO2 and oxygen/nitrogen atoms in this porous MOF structure. Co(II)-MOF nanoribbons with tetra-n-butylammonium bromide acted as cocatalysts with ∼97% yield of cyclic carbonate (reaction kinetic rate of 14.7 × 106 µmol g-1 h-1) upon the cycloaddition of epichlorohydrin (ECH) to CO2 (>99% reaction selectivity under solvent-free reaction condition at 80 °C, 3 h and 1 MPa CO2 pressure). This work may open a new avenue for chemical fixation of CO2 by rational design of the components and morphology of MOF-based catalysts.

A multifunctional α-Fe2O3@PEDOT core-shell nanoplatform for gene and photothermal combination anticancer therapy.

Exploration of versatile nanoplatforms within one single nanostructure for multidisciplinary treatment modalities, especially achieving a synergistic therapeutic efficacy of combinational gene/photothermal cancer therapy is still a great challenge in biomedicine and nanotechnology. In this study, a unique photothermal nanocarrier has successfully been designed and developed for a combination of gene therapy (GT) and photothermal therapy (PTT) of cancer cells. Surface-engineered iron oxides (α-Fe2O3) nanoparticles (NPs) with poly(3,4-ethylenedioxythiophene) (PEDOT) polymer coatings are synthesized using a one-pot in situ oxidative polymerization method. The results show that the as-prepared α-Fe2O3@PEDOT core-shell NPs with a uniform particle size exhibit positively charged surfaces, facilitating efficient siRNA Bcl-2 (B-cell lymphoma-2) uptake for delivery to breast cancer cells. More importantly, α-Fe2O3@PEDOT core-shell NPs not only display good biocompatibility and water dispersibility but also strong optical absorption enhancement in the Vis-NIR region as compared to α-Fe2O3 NPs. The obtained α-Fe2O3@PEDOT core-shell NPs show an efficient photothermal conversion efficacy (η = 54.3%) and photostability under NIR laser irradiation. As a result, both in vitro and in vivo biological studies on two types of breast cancer cells/tumors treated with α-Fe2O3@PEDOT-siRNA nanocomplexes demonstrate high cancer cell apoptosis and tumor inhibition induced by synergistic GT/PTT therapy under mild conditions compared to an individual GT or PTT alone. Taken together, this is the first example of the use of an α-Fe2O3@PEDOT core-shell nanoagent as a siRNA delivery nanocarrier for highly effective gene/photothermal combination anticancer therapy.

Photo-promoted in situ reduction and stabilization of Pd nanoparticles by H2 at photo-insensitive Sm2O3 nanorods.

Controlled synthesis of noble metal nanoparticles with well-defined size and good dispersion on supports has been a long-standing challenge in heterogeneous catalysis. Here we report a facile photo-assisted H2in situ reduction process to synthesize monodispersed Pd nanoparticles with 2-4 nm size on photo-insensitive Sm2O3 rare-earth metal oxide with nanorod morphology. Thanks to the contribution of UV irradiation, the photoelectrons generation in the Sm2O3 support accelerates the H2 reduction of Pd2+ ions into Pd0 and stabilize the growth of very small Pd nanoparticles homogeneously dispersed on the support. The homogeneous distribution of the Pd NPs on the surface of Sm2O3 is most likely attributed to the profuse nucleation sites created by the UV irradiation and the abundance of hydroxyl groups on the support. The hydrogenation of styrene to ethylbenzene was studied as a model reaction. As a result, the UV radiated sample shows an excellent TOF value of 7419 h-1, which is quadruple of the sample without UV irradiation, under the condition of 0.1 MPa H2 at a content of 1.0 wt% Pd. Besides, UV radiated sample shows a negligible performance degradation during the repeated cycling process. This photo-promoted H2 reduction process provides a convenient and straightforward route for assembling materials with novel structures and functions for nanotechnology applications.

Diversity of fungal pathogens associated with loquat and development of novel virulence scales.

Loquat [Eriobotrya japonica (Thunb.) Lindl.] is an important fruit crop in Pakistan; however, a constant decline in its production is noted due biotic and abiotic stresses, particularly disease infestation. Fungal pathogens are the major disease-causing agents; therefore, their identification is necessary for devising management options. This study explored Taxila, Wah-Cantt, Tret, Chatar, Murree, Kalar-Kahar, Choa-Saidan-Shah and Khan-Pur districts in the Punjab and Khyber Paktoon Khawa (KPK) provinces of Pakistan to explore the diversity of fungal pathogens associated with loquat. The samples were collected from these districts and their microscopic characterizations were accomplished for reliable identification. Alternaria alternata, Curvularia lunata, Lasiodiplodia theobromae, Aspergilus flavis, Botrytis cinerea, Chaetomium globosum, Pestalotiopsis mangiferae and Phomopsis sp. were the fungal pathogens infesting loquat in the study area. The isolates of A. alternata and C. lunata were isolated from leaf spots and fruit rot, while the isolates of L. theobromae were associated with twig dieback. The remaining pathogens were allied with fruit rot. The nucleotide evidence of internal transcribed spacer (ITS) regions (ITS1, 5.8S, and ITS2) were computed from all the pathogens and submitted in the database of National Center for Biotechnology Information (NCBI). For multigene analysis, beta-tubulin (BT) gene and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) regions were explored for A. alternata and C. lunata isolates, respectively. The virulence scales of leaf spots, fruit rot, and twig dieback diseases of loquat were developed for the first time through this study. It is the first comprehensive study with morpho-molecular identification, and newly developed virulence scales of the fungal pathogens associated with loquat, which improves the understanding of these destructive diseases.

Polydopamine Coated PB-MnO2 Nanoparticles as an Oxygen Generator Nanosystem for Imaging-Guided Single-NIR-Laser Triggered Synergistic Photodynamic/Photothermal Therapy.

Exploring a combined phototherapeutic strategy to overcome the limitations of a single mode therapy and inducing high anticancer efficiency is highly promising for precision cancer nanomedicine. However, a single-wavelength laser activates dual photothermal/photodynamic therapy (PTT/PDT) treatment is still a formidable challenge. Herein, we strategically design and fabricate a multifunctional theranostic nanosystem based on chlorin e6-functionalized polydopamine (PDA) coated prussian blue/manganese dioxide nanoparticles (PB-MnO2@PDA-Ce6 NPs). Interestingly, the obtained PB-MnO2@PDA NPs not only offer an effective delivery system for Ce6 but also provide strong optical absorption in the near-infrared range, endowing high antitumor efficacy of PTT. More importantly, the as-prepared PB-MnO2@PDA-Ce6 nanoagents exhibit an effective oxygen generation, superior reactive oxygen species (ROS), and outstanding photothermal conversion ability to greatly improve PTT and PDT treatments. As a result, both in vitro and in vivo treatments guided by MR imaging on liver cancer cells reveal the complete cell/tumor eradication under a single wavelength of 660 nm laser irradiation, implying the simultaneous synergistic PDT/PTT effects triggered by PB-MnO2@PDA-Ce6 nanoplatform, which are much higher than individual treatment. Taken together, our phototherapeutic nanoagents exhibit an excellent therapeutic performance, which may act as a nanoplatform to find safe and clinically translatable routes to accelerate cancer therapeutics.

A Hybrid VOx Incorporated Hexacyanoferrate Nanostructured Hydrogel as a Multienzyme Mimetic via Cascade Reactions.

Inspired by the cascade reactions occurring in micro-organelles of living systems, we have developed a hybrid hydrogel, a nanozyme that mimics three key enzymes including peroxidase, superoxide dismutase, and catalase. The organic/inorganic nanostructured hydrogel constituting VOx incorporated hexacyanoferrate Berlin green analogue complex (VOxBG) is prepared by a simple one-step hydrothermal process, and its composition, structure, and properties are thoroughly investigated. Polyvinylpyrrolidone, a low-cost and biocompatible polymer, was utilized as a scaffold to increase the surface area and dispersion of the highly active catalytic centers of the nanozyme. Compared to the widely used horseradish peroxidase in enzyme-linked immunosorbent assay, our VOxBG analogue hydrogel displays an excellent affinity toward the chromogenic substrate that is used in these peroxidase-based assays. This higher affinity makes it a competent nanozyme for detection and oxidation of biomolecules, including glucose, in a cascade-like system which can be further used for hydrogel photolithography. The VOxBG analogue hydrogel also holds a good ability for the rapid and efficient oxidative degradation of environmentally unfriendly recalcitrant substrates under light irradiation. Detailed mechanistic studies of this multifaceted material suggest that different complex catalytic processes and routes are involved in these photo-Fenton and Fenton reactions that are responsible for the generation as well as consumption of reactive oxygen species, which are effectively activated by a multienzyme mimetic of the VOxBG analogue hydrogel.

Plasmonic MoO3-x nanoparticles incorporated in Prussian blue frameworks exhibit highly efficient dual photothermal/photodynamic therapy.

Development of near infrared (NIR) light-responsive nanomaterials for high performance multimodal phototherapy within a single nanoplatform is still challenging in technology and biomedicine. Herein, a new phototherapeutic nanoagent based on FDA-approved Prussian blue (PB) functionalized oxygen-deficient molybdenum oxide nanoparticles (MoO3-x NPs) is strategically designed and synthesized by a facile one-pot size/morphology-controlled process. The as-prepared PB-MoO3-x nanocomposites (NCs) with a uniform particle size of ∼90 nm and high water dispersibility exhibited strong optical absorption in the first biological window, which is induced by plasmon resonance in an oxygen-deficient MoO3-x semiconductor. More importantly, PB-MoO3-x NCs not only exhibited a high photothermal conversion efficiency of ∼63.7% and photostability but also offered a further approach for the generation of reactive oxygen species (ROS) upon singular NIR light irradiation which significantly improved the therapeutic efficiency of the PB agent. Furthermore, PB-MoO3-x NCs showed a negligible cytotoxic effect in the dark, but an excellent therapeutic effect toward two triple-negative breast cancer (TNBC) cell lines at a low concentration (20 µg mL-1) of NCs and a moderate NIR laser power density. Additionally, efficient tumor ablation and metastasis inhibition in a 4T1 TNBC mouse tumor model can also be realized by synergistic photothermal/photodynamic therapy (PTT/PDT) under a single continuous NIR wave laser. Taken together, this study paved the way for the use of a single nanosystem for multifunctional therapy.

Synovial sarcoma of cervicodorsal spine: A case report.

Synovial sarcoma is a soft-tissue sarcoma. Its involvement of the spine is extremely rare. We report a 40 year old male who presented with shoulder pain and progressive weakness in all four limbs for six months with a visible, slowly growing bulge in his upper back. On examination he had quadriparesis and diffuse sensory deficit. MRI of the cervical spine showed a large soft tissue mass, iso to hypointense, extending into the neural canal, compressing the cord. The mass had a few internal areas of contrast enhancement with extension into the right paraspinal regions involving the vertebral bodies. Sub-periosteal spine dissection was done. Tumour was primarily extradural, involving and extending from paraspinal soft tissues to the posterior arches, laminae and spinous processes of the verteberae, with their destruction. Gross radical removal of the visible mass was done, followed by three cycles of radiation therapy. Excisional biopsy showed synovial sarcoma TYPE II. In conclusion, synovial sarcomas should be kept in the differentials of a mass arising in spinal axis.

Intrinsic peroxidase-like activity and enhanced photo-Fenton reactivity of iron-substituted polyoxometallate nanostructures.

Heteropolyacids (HPAs) are a class of polyoxometallates (POMs) with oxygen-rich surfaces. Herein, we have developed an Fe-containing heteropolyacid by cation-exchange and employed KFePW12O40 nanostructures for Fenton, photo-Fenton and enzyme-mimetic reactions. The as-prepared KFePW12O40 catalyst exhibits efficient degradation of Rhodamine B (RhB) via the photo-Fenton reaction. As an enzyme-mimetic, this material can effectively oxidize TMB and dopamine. The obtained nanomaterials were characterized via SEM, TEM, XPS, BET surface area, TGA, UV-Vis spectroscopy, FT-IR, and XRD techniques. The photocatalyst has a relatively large surface area of 38 m2 g-1, and the Keggin structure of phosphotungstic ions is kept intact during the preparation. The RhB dye pollutants can be efficiently bleached and degraded up to about 80% within a one hour photo-Fenton reaction under visible light irradiation. Our results indicate that the KFePW12O40 nanomaterial can effectively mimic the enzyme cascade reaction of horseradish peroxidase (HRP). It also has a high affinity toward 3,3',5,5'-tetramethylbenzidine (TMB) for oxidation and henceforth, it has been used for the colorimetric assay of dopamine and H2O2. Overall, our study suggests that KFePW12O40 can be used for the efficient degradation of environmental pollutants. The KFePW12O40 catalyst is stable and can be easily separated from the reaction system for reuse without an obvious loss of activity.

Highly dispersed ultra-small Pd nanoparticles on gadolinium hydroxide nanorods for efficient hydrogenation reactions.

Heterogeneous catalytic hydrogenation reactions are of great importance to the petrochemical industry and fine chemical synthesis. Herein, we present the first example of gadolinium hydroxide (Gd(OH)3) nanorods as a support for loading ultra-small Pd nanoparticles for hydrogenation reactions. Gd(OH)3 possesses a large number of hydroxyl groups on the surface, which act as an ideal support for good dispersion of Pd nanoparticles. Gd(OH)3 nanorods are prepared by hydrothermal treatment, and Pd/Gd(OH)3 catalyst with a low loading of 0.95 wt% Pd is obtained by photochemical deposition. The catalytic hydrogenation of p-nitrophenol (4-NP) to p-aminophenol (4-AP) and styrene to ethylbenzene is performed as a model reaction. The obtained Pd/Gd(OH)3 catalyst displays excellent activity as compared to other reported heterogeneous catalysts. The rate constant of 4-NP reduction is measured to be 0.047 s-1 and the Pd/Gd(OH)3 nanocatalyst shows no marked loss of activity even after 10 consecutive cycles. Additionally, the hydrogenation of styrene to ethylbenzene over Pd/Gd(OH)3 nanorods exhibits a turnover frequency (TOF) as high as 6159 h-1 with 100% selectivity. Moreover, the catalyst can be recovered by centrifugation and recycled for up to 5 consecutive cycles without obvious loss of activity. Our results indicate that Gd(OH)3 nanorods act as a promoter to enhance the catalytic activity by providing a synergistic effect from the strong metal support interaction and the large surface area for high dispersion of small sized Pd nanoparticles enriched with hydroxyl groups on the surface. The high performance of Pd/Gd(OH)3 in heterogeneous catalysis offers a new, efficient and facile strategy to explore other metal hydroxides or oxides as supports for organic transformations.

One-Step Growth of Iron-Nickel Bimetallic Nanoparticles on FeNi Alloy Foils: Highly Efficient Advanced Electrodes for the Oxygen Evolution Reaction.

Electrochemical water splitting is an important process to produce hydrogen and oxygen for energy storage and conversion devices. However, it is often restricted by the oxygen evolution reaction (OER) due to its sluggish kinetics. To overcome the problem, precious metal oxide-based electrocatalysts, such as RuO2 and IrO2, are widely used. The lack of availability and the high cost of precious metals compel researchers to find other resources for the development of cost-effective, environmentally friendly, earth-abundant, nonprecious electrocatalysts for OER. Such catalysts should have high OER performance and good stability in comparison to those of available commercial precious metal-based electrocatalysts. Herein, we report an inexpensive fabrication of bimetallic iron-nickel nanoparticles on FeNi-foil (FeNi4.34@FeNi-foil) as an integrated OER electrode using a one-step calcination process. FeNi4.34@FeNi-foil obtained at 900 °C shows superior OER activity in alkaline solution with an overpotential as low as 283 mV to achieve a current density of 10 mA cm-2 and a small Tafel slope of 53 mV dec-1. The high performance and durability of the as-prepared nonprecious metal electrode even exceeds those of the available commercial RuO2 and IrO2 catalysts, showing great potential in replacing the expensive noble metal-based electrocatalysts for OER.

Risk of In-Hospital Cardiac Arrest Among Medicare Beneficiaries Undergoing Video Electroencephalographic Monitoring.

PURPOSE: Sudden cardiac death is the dominant reason of sudden unexpected death in epilepsy (SUDEP). Anecdotal reports have documented cardiac arrest during video electroencephalographic (EEG) monitoring. We performed this study to determine the rate of cardiac arrest and need for cardiac resuscitation during video EEG monitoring. METHODS: We used inpatient data from the Centers for Medicare and Medicaid Services (CMS)'s Linkable 2008-2010 Medicare Data Entrepreneur's Synthetic Public Use File. Using the International Classification of Diseases 9th revision (ICD-9) primary diagnosis codes, we identified patients with epilepsy. We used the primary or secondary ICD-9 procedure codes to identify patients who underwent video EEG during admission. For primary endpoints, we identified patients who suffered cardiac arrest and those who underwent cardiorespiratory resuscitation (CPR). RESULTS: A total of 6,087 patients (mean age 76±12 years; 3,354 women) were included; 5,597 patients had a primary diagnosis of epilepsy and no video EEG, 240 patients had a primary diagnosis of epilepsy and underwent video EEG, and 250 patients underwent a video EEG without any diagnosis of epilepsy. A total of 12 patients (0.2%, 95% CI: 0.7-0.8) suffered a cardiac arrest during their admission. Three patients (0.1%) underwent CPR during their admission. There was no in-hospital mortality. None of the patients in those undergoing video EEG suffered cardiac arrest or underwent CPR. CONCLUSION: While the risk of cardiac arrest during video EEG monitoring may exist, the rate of such events was negligible in our study comprising of elderly Medicare patients.

Prevalence of and Factors Associated with Dural Thickness in Patients with Mild Cognitive Impairment and Alzheimer's Disease.

BACKGROUND AND PURPOSE: We performed this study to evaluate the prevalence of and factors associated with dural thickening in patients with mild cognitive impairment and Alzheimer's disease. METHODS: Alzheimer's disease neuroimaging initiative participants with axial FLAIR sequence magnetic resonance imaging (MRI) images were analyzed. Dural thickness was defined by a linear strip of hyperintense tissue signal along the dura mater observed in at least two different images without evidence of leptomeningeal involvement. RESULTS: Dural thickening was seen in 83 (34%) of 242 persons analyzed (mean age [±SD] 74±7 years: 150 were men) with either mild cognitive impairment or Alzheimer's disease. The mini mental score was not different in persons with (26±0.3) and without (26±0.2) dural thickening (p = 0.6). The proportion of patients with moderate or severe cognitive impairment (defined by mini mental status score) was similar at baseline and at 12-month evaluations. The rates of annual progression according to Alzheimer's disease assessment scale (p = 0.06) and clinical dementia scale (p = 0.001) were higher in persons without dural thickening. The annual rate of volume loss in entorhinal cortex was higher among persons with dural thickening. CONCLUSIONS: We found relatively high prevalence of dural thickening in patients with mild cognitive impairment and Alzheimer's disease.