A Cellulose-Based Dual-Crosslinked Framework with Sensitive Shape and Color Changes in Acid/Alkaline Vapors.

Cellulose detectors, as green sensors, are some of the defensive mechanisms of plants which combat environmental stresses. However, extracted cellulose struggles to fulfil these functionalities due to its rigid physical/chemical properties. In this study, a novel cellulose dual-crosslinked framework (CDCF) is proposed. This comprises a denser temporary physical crosslinking bond (hydrogen bonding) and a looser covalent crosslinking bond (N,N-methylenebisacrylamide), which create deformable spaces between the two crosslinking sites. Abundant pH-sensitive carboxyl groups and ultralight, highly porous structures make CDCF response very sensitive in acid/alkaline vapor environments. Hence, a significant shrinkage of CDCF was observed following exposure to vapors. Moreover, a curcumin-incorporated CDCF exhibited dual shape and color changes when exposed to acid/alkaline vapors, demonstrating great potential for the multi-detection of acid/alkaline vapors.

A Modified Targetoid Feature Emphasizing Thin-Rim APHE to Improve the Diagnostic Performance of LI-RADS for Malignant Hepatic Tumors.

Objective: To identify imaging features that help distinguish between HCCs and non-HCC malignancies assigned to LI-RADS M (LR-M) and evaluate the diagnostic performance of a LI-RADS with targetoid criteria using thin-rim arterial phase hyperenhancement (APHE). Materials and Methods: This retrospective study included 381 patients (387 observations) at high-risk for HCC who underwent enhanced-MRI before surgery. Three radiologists reviewed images for LI-RADS categorization of hepatic observations. Univariate and multivariate analysis was conducted to determine reliable features to differentiate between HCC and non-HCC malignancies among the LR-M lesions. The thin-rim (<30%) APHE was defined based on the thickest thickness of rim APHE compared with the tumor radius, and a modified LI-RADS emphasizing thin-rim APHE as a specific feature of LR-M was established. We compared the diagnostic performance of modified LR-M and LI-RADS 5 (LR-5) with the conventional one. Results: Thin-rim APHE and targetoid diffusion-weighted imaging (DWI) were found as independent predictive factors of non-HCC malignancies, while enhancing capsule, thick-rim APHE and peripheral washout were noted as independent variables significantly associated with HCC of LR-M (P<0.05). The noticeable diagnostic performance of thin-rim APHE in distinguishing non-HCC malignancies from HCCs using the ROC curve. Emphasizing thin-rim APHE on targetoid features, the modified LR-M revealed significantly superior specificity and accuracy (89.4% vs 81.1%, P=0.004; and 87.9% vs 82.2%, P=0.027, respectively) while maintaining high sensitivity (82.2% vs 86.0%; P=0.529) compared with the LR-M. Meanwhile, the modified LR-5 achieved greater sensitivity and accuracy (88.6% vs 79.7%, P=0.004; and 85.8% vs 80.1%, P=0.036, respectively) for diagnosing HCC, without compromising specificity (78.3% vs.81.1%; P=0.608) compared with the LR-5. Conclusion: Thin-rim APHE may be the specific imaging feature for differentiating non-HCC malignancies from HCCs within LR-M. The modified targetoid criteria emphasizing thin-rim APHE can improve the diagnostic performance of LI-RADS for hepatic malignancies.

Direct C-H Sulfuration: Synthesis of Disulfides, Dithiocarbamates, Xanthates, Thiocarbamates and Thiocarbonates.

In light of the important biological activities and widespread applications of organic disulfides, dithiocarbamates, xanthates, thiocarbamates and thiocarbonates, the continual persuit of efficient methods for their synthesis remains crucial. Traditionally, the preparation of such compounds heavily relied on intricate multi-step syntheses and the use of highly prefunctionalized starting materials. Over the past two decades, the direct sulfuration of C-H bonds has evolved into a straightforward, atom- and step-economical method for the preparation of organosulfur compounds. This review aims to provide an up-to-date discussion on direct C-H disulfuration, dithiocarbamation, xanthylation, thiocarbamation and thiocarbonation, with a special focus on describing scopes and mechanistic aspects. Moreover, the synthetic limitations and applications of some of these methodologies, along with the key unsolved challenges to be addressed in the future are also discussed. The majority of examples covered in this review are accomplished via metal-free, photochemical or electrochemical approaches, which are in alignment with the overraching objectives of green and sustainable chemistry. This comprehensive review aims to consolidate recent advancements, providing valuable insights into the dynamic landscape of efficient and sustainable synthetic strategies for these crucial classes of organosulfur compounds.

A Biomimetic Lignocellulose Aerogel-Based Membrane for Efficient Phenol Extraction from Water.

Rapid extraction and concentration systems based on green materials such as cellulose or lignin are promising. However, there is still a need to optimize the material properties and production processes. Unlike conventional cellulose or lignin sorbent materials, aquatic reed root cells can concentrate external organic pollutants in the water and accumulate them in the plant. Inspired by this, a new nanocellulose-lignin aerogel (NLAG) was designed, in which nanocellulose was used as a substrate and lignin and polyamide epoxy chloropropane were used to crosslink cellulose in order to enhance the strength of the NLGA, resulting in good mechanical stability and water-oil amphiphilic properties. In practical applications, the organic membrane on the NLAG can transport organic pollutants from water to the NLAG, where they are immobilized. This is evidenced by the fact that the aerogel can remove more than 93% of exogenous phenol within a few minutes, highly enriching it inside. In addition, the aerogel facilitates filtration and shape recovery for reuse. This work establishes a novel biopolymer-aerogel-based extraction system with the advantages of sustainability, high efficiency, stability, and easy detachability, which are hard for the traditional adsorbent materials to attain.

Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp2)-H and C(sp3)-H bonds.

Organochalcogen compounds are prevalent in numerous natural products, pharmaceuticals, agrochemicals, polymers, biological molecules and synthetic intermediates. Direct chalcogenation of C-H bonds has evolved as a step- and atom-economical method for the synthesis of chalcogen-bearing compounds. Nevertheless, direct C-H chalcogenation severely lags behind C-C, C-N and C-O bond formations. Moreover, compared with the C-H monochalcogenation, reports of selective mono-/dichalcogenation and exclusive dichalcogenation of C-H bonds are relatively scarce. The past decade has witnessed significant advancements in selective mono-/dichalcogenation and exclusive dichalcogenation of various C(sp2)-H and C(sp3)-H bonds via transition-metal-catalyzed/mediated, photocatalytic, electrochemical or metal-free approaches. In light of the significance of both mono- and dichalcogen-containing compounds in various fields of chemical science and the critical issue of chemoselectivity in organic synthesis, the present review systematically summarizes the advances in these research fields, with a special focus on elucidating scopes and mechanistic aspects. Moreover, the synthetic limitations, applications of some of these processes, the current challenges and our own perspectives on these highly active research fields are also discussed. Based on the substrate types and C-H bonds being chalcogenated, the present review is organized into four sections: (1) transition-metal-catalyzed/mediated chelation-assisted selective C-H mono-/dichalcogenation or exclusive dichalcogenation of (hetero)arenes; (2) directing group-free selective C-H mono-/dichalcogenation or exclusive dichalcogenation of electron-rich (hetero)arenes; (3) C(sp3)-H dichalcogenation; (4) dichalcogenation of both C(sp2)-H and C(sp3)-H bonds. We believe the present review will serve as an invaluable resource for future innovations and drug discovery.

AI-assisted compressed sensing and parallel imaging sequences for MRI of patients with nasopharyngeal carcinoma: comparison of their capabilities in terms of examination time and image quality.

OBJECTIVE: To compare examination time and image quality between artificial intelligence (AI)-assisted compressed sensing (ACS) technique and parallel imaging (PI) technique in MRI of patients with nasopharyngeal carcinoma (NPC). METHODS: Sixty-six patients with pathologically confirmed NPC underwent nasopharynx and neck examination using a 3.0-T MRI system. Transverse T2-weighted fast spin-echo (FSE) sequence, transverse T1-weighted FSE sequence, post-contrast transverse T1-weighted FSE sequence, and post-contrast coronal T1-weighted FSE were obtained by both ACS and PI techniques, respectively. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and duration of scanning of both sets of images analyzed by ACS and PI techniques were compared. The images from the ACS and PI techniques were scored for lesion detection, margin sharpness of lesions, artifacts, and overall image quality using the 5-point Likert scale. RESULTS: The examination time with ACS technique was significantly shorter than that with PI technique (p < 0.0001). The comparison of SNR and CNR showed that ACS technique was significantly superior with PI technique (p < 0.005). Qualitative image analysis showed that the scores of lesion detection, margin sharpness of lesions, artifacts, and overall image quality were higher in the ACS sequences than those in the PI sequences (p < 0.0001). Inter-observer agreement was evaluated for all qualitative indicators for each method, in which the results showed satisfactory-to-excellent agreement (p < 0.0001). CONCLUSION: Compared with the PI technique, the ACS technique for MR examination of NPC can not only shorten scanning time but also improve image quality. CLINICAL RELEVANCE STATEMENT: The artificial intelligence (AI)-assisted compressed sensing (ACS) technique shortens examination time for patients with nasopharyngeal carcinoma, while improving the image quality and examination success rate, which will benefit more patients. KEY POINTS: • Compared with the parallel imaging (PI) technique, the artificial intelligence (AI)-assisted compressed sensing (ACS) technique not only reduced examination time, but also improved image quality. • Artificial intelligence (AI)-assisted compressed sensing (ACS) pulls the state-of-the-art deep learning technique into the reconstruction procedure and helps find an optimal balance of imaging speed and image quality.

Gradient assembly of alginic acid/quaternary chitosan into biomimetic hidden nanoporous textiles for thermal management.

Hidden pores (including compact shell and porous core pores) occur naturally in polar animals' feathers/fur, and they show exceptional capability for thermal insulation. The facile implementation of such an architecture in macroscopic fibers is challenging. In this work, gradient assembly is developed to prepare biological hidden nanoporous fibers (average aperture, ~80 nm). Namely, a weak polyanion (alginic acid) and a polycation (quaternary chitosan) were dissolved in dimethyl sulphoxide (the anion charge of alginic acid was largely shielded) and then spun to ethanol/water/ammonia solution, whereby ammonia triggered the polymer assembly from the shell to the core. This presents an efficient process in 20 min, which is in stark contrast to tedious freeze-spinning or template methods. The as-prepared green textiles featuring much lower thermally conductivity (0.033 W m-1 K-1) compared with the conventional microporous/compact fibers, as well as robust mechanical strength and enhanced solar/electric-heat-harvesting properties, holding great potential to replace the unsustainable animal products.

The risk factors of hemorrhage in stereotactic needle biopsy for brain lesions in a large cohort: 10 years of experience in a single center.

BACKGROUND: This study aimed to identify the risk factors for hemorrhage from a large cohort who underwent stereotactic needle biopsy for brain lesions at a single center over a 10-year period. METHODS: We performed a retrospective chart review of consecutive patients who underwent stereotactic biopsy at our institute between January 2010 and December 2019. Demographic characteristics and clinical variables were collected and analyzed to identify risk factors for postbiopsy hemorrhage using the chi-square test and univariable and multivariable logistic regression analyses. RESULTS: A total of 3196 patients were included in this study; of these, a histological diagnosis was eventually made for 2938 (91.93%) patients. Hemorrhage occurred in 149 (4.66%) patients, and symptomatic hemorrhage occurred in 46 (1.44%) patients. In multivariable logistic regression analyses, the presence of deep-seated lesions (OR 1.272, p = 0.035), concomitant edema and enhancement on MR imaging scans (OR 1.827, p = 0.002), intraoperative hypertension without a past history (OR 1.012, p = 0.024), and the presence of high-grade glioma (OR 0.306, p = 0.003) were identified as independent predictors of hemorrhage after biopsy. CONCLUSION: Stereotactic needle biopsy is a safe and effective way to obtain tissue from brain lesions for histological diagnosis. The presence of deep-seated lesions, concomitant edema, and enhancement on MR imaging scans and the presence of high-grade glioma are independent predictors of hemorrhage after stereotactic biopsy.

Imaging algorithm and multimodality evaluation of spinal osteoblastoma.

BACKGROUND: To analyze the features of CT, MRI and PET/CT and their diagnostic value for spinal osteoblastomas (OBs). METHODS: The radiological and clinical data of 21 patients with histopathologically-confirmed spinal OBs were analyzed retrospectively. RESULTS: Sixteen of the 21 cases were benign and 5 were aggressive OBs. Tumors were located in the lumbar (n = 11), cervical (n = 4), thoracic (n = 5), and sacral (n = 1) spinal regions. Nineteen cases were centered in the posterior elements of the spine, 13 of which extended into the vertebral body. Punctate or nodular calcifications were found in all cases on CT with a complete sclerotic rim (n = 12) or incomplete sclerotic rim (n = 8). The flare phenomenon (indicative of surrounding tissue inflammation) was found in 17/21 cases on CT, thin in 11 cases and thick in 6 cases, and in 19/19 cases on MRI, thin in 1 case and thick in 18 cases. On 18F-FDG PET/CT, all cases (8/8) were metabolically active with the SUVmax of 12.3-16.0; the flare sign was observed in 8 cases, including 7 cases of hypometabolism and 1 case of coexistence of hypermetabolism and hypometabolism. Based on CT, 3, 12, and 6 cases were classified as Enneking stage 1, 2 and 3, respectively. Of 19 cases with MRI, 1 and 18 cases were classified as Enneking stage 2 and 3, respectively. CONCLUSIONS: Spinal OB has multiple unique characteristic radiological features. Although a larger sample size is needed, combining CT, MRI and PET may be beneficial to optimize preoperative diagnosis and care of patients with OBs.

A Novel Quinazolinone Derivative as Fluorescence Quenching Off-On Sensor for High Selectivity of Fe(3+).

A novel quinazolinone compound containing quinazoline-fused moiety has been synthesized as fluorescence Off-On sensor QQ. The probe exhibited highly selective and sensitive recognition toward trivalent ferric ion (Fe(3+)) over other metal ions in HEPES buffer solution (10 mM, pH = 7.0, DMF-H2O, 9:1, v/v). The significant quenching in the fluorescence spectral could be served as a selective fluorescence Off-On sensor. The titration study indicated the formation of 1:1 complex between QQ and Fe(3+).

Synthesis of pyridine-based 1,3,4-oxadiazole derivative as fluorescence turn-on sensor for high selectivity of Ag+.

An oxadiazole derivative(OXD) containing symmetrical pyridine-2-formamidophenyl-binded moiety was synthesised as fluorescence turn-on sensor OA1. Its ultraviolet-visible(UV-vis) and fluorescent spectra(FS) gave prominent fluorescence enhancement only for monovalent silver ion(Ag(+)) in HEPES buffer solution (10 mM, pH = 7.0, DMF-H2O, 9:1, v/v), which indicated the photo-induced electron transfer(PET) occurred from the donor of pyridine-2-formamidophenyl group to oxadiazole fluorophore. The present study demonstrated that OA1 was a viable candidate as fluorescent receptor for a new Ag(+) sensor. And the results of fluorescent spectral titration showed this sensor formed 1:1 complex with Ag(+).

Ethyl 2-[1,3-dioxo-6-(piperidin-1-yl)-2,3-dihydro-1H-benz[de]isoquinolin-2-yl]acetate.

In the title compound, C(21)H(22)N(2)O(4), the naphthalimide unit is almost planar (r.m.s. deviation = 0.081Å). The carboximide N atom and the five C atoms of the eth-oxy-carbonyl-methyl substituent also lie close to a common plane (r.m.s. deviation = 0.119Å), which subtends an angle of 71.06 (8)° to the naphthalamide plane. The piperidine ring adopts a chair conformation. In the crystal, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into zigzag chains along the a axis.

1,1'-[(1,3-Dihydroxypropane-2,2-diyl)dimethylene]dipyridinium bis-(hexa-fluoro-phosphate).

The title compound, C(15)H(20)N(2)O(2) (2+)·2PF(6) (-), was prepared by anion exchange of two bromide ions in the ionic liquid 2,2'-bis-(pyridinium-1-ylmeth-yl)-propane-1,3-diol dibromide with potassium hexa-fluoro-phosphate. The two pyridine rings are planar (r.m.s. deviations = 0.008 and 0.00440 Å) and make a dihedral angle of 44.0 (2)°. Intermolecular O-H⋯F and C-H⋯F interactions occur. The four F atoms in each anion were refined as disordered over two sets of sites with an occupancy ration of 0.700 (19):0.300 (19).

3,3-Dimethyl-1,1-(propane-1,3-di-yl)diimidazol-1-ium tetra-bromido-cadmate(II).

The title compound, (C(11)H(18)N(4))[CdBr(4)], was prepared by an anion exchange. The dihedral angle between the two planar imidazolium rings in the cation is 74.4 (4)°. The crystal packing is stabilized by weak inter-molecular C-H⋯Br hydrogen bonds between the cation and the tetrahedral anion, building up a three-dimensionnal network.