Film-Forming Capability and Antibacterial Activity of Surface-Deacetylated Chitin Nanocrystals: Role of Degree of Deacetylation.

Developing sustainable food-active packaging materials is a major issue in food preservation applications. Chitin nanocrystals (ChNCs) are regarded as unique bioderived nanomaterials due to their inherent nitrogen moiety. By tuning the chemical functionality of this nanomaterial, it is possible to affect its properties, such as film-forming capability and antibacterial activity. In this work, surface-deacetylated chitin nanocrystals (D-ChNCs) with different degrees of deacetylation (DDs) were prepared by partial deacetylation of native chitin and subsequent acid hydrolysis, and their film-forming capability and antibacterial activity were studied systematically. The D-ChNCs showed favorable film-forming ability and antibacterial activity, which are closely related to their DD. With the increase in DD (from 5.7% to 45.4%), the formed transparent films based on ChNCs showed gradually increased elongation at break (from 0.5% to 2.5%) and water contact angle (from 25.5° to 87.0°), but decreased break strength (from 3.13 to 0.89 MPa), Young's modulus (from 0.84 to 0.24 MPa), and water vapor permeability (from 4.7 × 10-10 to 4.1 × 10-10g/m s Pa). Moreover, the antibacterial activity of the D-ChNCs against E. coli and S. aureus also increased with the increase of DD. This study also found that the depolarization and potential dissipation of the bacterial cell membrane induced by the contact between amino-rich D-ChNCs and bacteria through electrostatic attraction are the possible mechanisms causing bacterial cell death. This study provides a basis for understanding the effects of DD on the film-forming capability and antibacterial activity of ChNCs, which is conducive to the design of novel active packaging films based on ChNCs.

Role of TFEB-autophagy lysosomal pathway in palmitic acid induced renal tubular epithelial cell injury.

Lysosomal dysfunction and impaired autophagic flux are involved in the pathogenesis of lipotoxicity in the kidney. Here, we investigated the role of transcription factor EB (TFEB), a master regulator of autophagy-lysosomal pathway, in palmitic acid induced renal tubular epithelial cells injury. We examined lipid accumulation, autophagic flux, expression of Ps211-TFEB, and nuclear translocation of TFEB in HK-2 cells overloaded with palmitic acid (PA). By utilizing immunohistochemistry, we detected TFEB expression in renal biopsy tissues from patients with diabetic nephropathy and normal renal tissue adjacent to surgically removed renal carcinoma (controls), as well as kidney tissues from rat fed with high-fat diet (HFD) and low-fat diet (LFD). We found significant lipid accumulation, increased apoptosis, accompanied with elevated Ps211-TFEB, decreased nuclear TFEB, reduced lysosome biogenesis and insufficient autophagy in HK-2 cells treated with PA. Kidney tissues from patients with diabetic nephropathy had lower nuclear and total levels of TFEB than that in control kidney tissues. Level of renal nuclear TFEB in HFD rats was also lower than that in LFD rats. Exogenous overexpression of TFEB increased the nuclear TFEB level in HK-2 cells treated with PA, promoted lysosomal biogenesis, improved autophagic flux, reduced lipid accumulation and apoptosis. Our results collectively indicate that PA is a strong inducer for TFEB phosphorylation modification at ser211 accompanied with lower nuclear translocation of TFEB. Impairment of TFEB-mediated lysosomal biogenesis and function by palmitic acid may lead to insufficient autophagy and promote HK-2 cells injury.

Impact of coronary artery disease in patients with hypertrophic cardiomyopathy.

BACKGROUND: Atherosclerotic coronary artery disease (CAD) often occurs concurrently with hypertrophic cardiomyopathy (HCM). However, the influence of concomitant CAD has not been fully assessed in patients with HCM. METHODS: Invasive or computed tomography coronary angiography was performed in 461 patients with HCM at our hospital to determine the presence and severity of CAD from March 2010 to April 2022. The primary end points were all-cause, cardiovascular, and sudden cardiac deaths. The survival of HCM patients with severe CAD was compared with that of HCM patients without severe CAD. RESULTS: Of 461 patients with HCM, 235 had concomitant CAD. During the median (interquartile range) follow-up of 49 (31-80) months, 75 patients (16.3%) died. The 5-year survival estimates were 64.3%, 82.5%, and 86.0% for the severe, mild-to-moderate, and no-CAD groups, respectively (log-rank, p = 0.010). Regarding the absence of cardiovascular death, the 5-year survival estimates were 68.5% for patients with severe CAD, 86.4% for patients with mild-to-moderate CAD, and 90.2% for HCM patients with no CAD (log-rank, p = 0.001). In multivariate analyses, severe CAD was associated with all-cause and cardiovascular death after adjusting for age, left ventricular ejection fraction, hypertension, and atrial fibrillation. CONCLUSIONS: This study showed a worse prognosis among HCM patients with severe CAD than among HCM patients without severe CAD. Therefore, timely recognition of severe CAD in HCM patients and appropriate treatment are important.

A highly sensitive and selective ratiometric sensing platform based on 7-amino-4-methylcoumarin for naked-eye visual fluorescence sensing of Cu2.

Cu2+ is a major environmental pollutant. An efficient measurement for Cu2+ is urgently needed. In this report, we have developed a new sensitive and selective ratiometric sensing platform using 7-amino-4-methylcoumarin (AMC) for detecting Cu2+ in real samples. In the presence of Cu2+, o-phenylenediamine (OPD) could be catalytically oxidized to 2,3-diaminophenazine (DAP), which could react with AMC, leading to quench the fluorescence intensity of AMC at 438 nm. Meanwhile, DAP provided a new emission peak at 557 nm. Based on the efficient overlapped spectrum of AMC and DAP, a ratiometric sensing platform through fluorescence resonance energy transfer (FRET) was carried out. Furthermore, the as-proposed strategy displayed the linear relationship in the wide range from 6 to 250 µM with a low detection limit of 0.059 µM, and the recoveries of the spiked samples in real samples ranged from 86.5% to 110.1%. Moreover, comparing the visual fluorescence colors of the real samples with the standard colorimetric card, we used the as-proposed strategy as a solid-based platform for realizing an efficient semi-quantitative detection of Cu2+ via naked-eye visual fluorescence mode without any complicated instrument and operation. The above results implied that the as-proposed strategy could be used in the practice determination of Cu2+.

Novel synthesis of Mn: ZnSe@ZnS core-shell quantum dots based on photoinduced fluorescence enhancement.

A novel Type-I Mn: ZnSe@ZnS core-shell quantum dots (QDs) was reported through a two-step procedure by using low-cost inorganic salts and naturalbiomacromolecule as raw materials. Based on a designed structure of L-cysteine-capped Mn: ZnSe QDs in aqueous media with the controllable surface, Mn: ZnSe@ZnS core-shell QDs were formed due to photoactive ions and defect curing under continuous constant light. The influences of experimental variables, including synthesis conditions of Mn: ZnSe QDs, different types and affecting factors of photo irradiation had been systematically investigated. Under the effect of photoinduced fluorescence enhancement, the photoluminescence (PL) intensity increases significantly by about 5-10 times after 1-3 h of UV irradiation. The position of the fluorescence peak was red-shifted by about 17 nm, emitting orange-red fluorescence. The photoluminescence quantum yield (PL QY) was markedly improved (up to 35%). The structure and morphology of Mn: ZnSe@ZnS core-shell QDs were also confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS) in detail. The mechanism of photoinduced fluorescence enhancement was attributed to L-cysteine allowed to release S2- to form a ZnS shell, and the passivated surface non-radiative relaxation centers of Mn: ZnSe@ZnS QDs was successfully synthesized with highuniform size, excellent photoluminescence performance, and good stability, all ofwhichmakethemgood potential candidates for white LEDs, and biological labels.

[Quantification and fast-screening of malachite green in aquaculture water using paper spray ionization mass spectrometry].

OBJECTIVE: A rapid quantitative technique had been developed for the screening of malachite green(MG) in aquaculture water using paper spray ionization mass spectrometry(PSI-MS). METHODS: To rapid extract MG, chloroform and deep eutectic solvents(DESs) were used as extraction agent and co-solvent respectively. malachite green D_5(MG-D_5) was used as an internal standard to quantitative determination MG, C_(18) chromatographic column(4. 6 mm×250 mm, 5 µm). RESULTS: The method showed a good linearity(R~2=0. 999) in the concentration range of 0. 1-10 µg/mL with the detection limit of 0. 03 µg/mL and the quantitative limit of 0. 1 µg/mL. The intra-and inter-day precisions were 3. 5% and 6. 2%, and the recovery ranged from 98. 9% to 106. 9%(n=7). The detection result by PSI-MS were in agreement with those by liquid chromatography-tandem mass spectrometry(LC-MS/MS), but the run time was only 1 min each sample. CONCLUSION: The method is accurate and reliable. And compared with the conventional LC-MS/MS technology, it is simple, rapid and low-cost.

Rapid analysis of benzoic acid and vitamin C in beverages by paper spray mass spectrometry.

A paper spray mass spectrometry (PS-MS) method has been developed for the rapid quantification of benzoic acid (BA) and vitamin C (VC) in beverages. Using BA-d5 as an internal standard (IS) to analyze BA and VC, the calibration curves ranged from 0.3 to 100 µg/mL for BA and 1 to 100 µg/mL for VC, the linearity was 0.9996 for BA and 0.9973 for VC. The limits of detection (LODs) and limits of quantitation (LOQs) were 0.1 µg/mL and 0.3 µg/mL for BA, 0.3 µg/mL and 1 µg/mL for VC, respectively. The recovery ranged from 91.1 to 106.7% for BA, 92.6 to 108.2% for VC. Compared with HPLC, there is no substantial difference in the quantification of BA and VC in samples, the accuracy was 95.7-102.2%, and the run time is far less than that of the HPLC method. The results indicated that PS-MS is a rapid, environmentally friendly and high-throughput method for the quantification of BA and VC.

Rapid Analysis of Illegal Cationic Dyes in Foods and Surface Waters Using High Temperature Direct Analysis in Real Time High-Resolution Mass Spectrometry.

A high temperature desorption (HTD) direct analysis in real time-high-resolution mass spectrometric (DART-HRMS) method was developed for the rapid analysis of four banned cationic dyes. Rhodamine B is used to dye foods, while malachite green, crystal violet, and methylene blue are added to fishponds as antimicrobials. A simple induced phase separation extraction was used to pretreat samples. The DART-HRMS method employed two temperature steps, i.e., 200 °C for drying, purification, and enrichment of sample solution and 500 °C for thermal desorption and ionization of analytes. The calibration curves of dyes in the range of 50-2000 ng/mL were linear using deuterated malachite green as an internal standard. The LODs vary for all analytes between 0.1 and 30 ppb depending on the matrix and experimental conditions. Through analyses of real samples, two chili powders and one chili oil were found to be contaminated by rhodamine B. The concentrations were comparable with those found by an HPLC-MS/MS method.

Rapid analysis of benzalkonium chloride using paper spray mass spectrometry.

A paper spray mass spectrometry (PS-MS) method for rapid and reliable analysis of benzalkonium chloride (BAC) in compound eye drops and body surface disinfectant was developed. The sample was dropped onto triangular filter paper, and high voltage (3.5kV) was applied to form an electrospray. This method can provide the composition of benzalkonium chloride in samples without pretreatment, solvent or chromatographic separation, and the analysis time is only 10s. The primary homologues C12-BAC, C14-BAC and C16-BAC of benzalkonium chloride were quantitatively analyzed using PS-MS. Samples were subjected to simple dilution and quantified using the internal standard method. Ion trap mass spectrometry was scanned using SIM mode. The linear ranges of C12-BAC, C14-BAC and C16-BAC were 1-100µgmL-1; the linear regression coefficients were 0.998-0.999; the detection limits (LODs) were 0.1µgmL-1; the limit of quantifications (LOQs) was <1µgmL-1, and the method validation indicated that the method precision and accuracy were good. Compared with HPLC-UV methods, there was no significant difference in the quantitative determination of the actual samples, but the analysis time for PS-MS is shorter (2min). In addition, reagent consumption in PS-MS is small, and no chromatographic separation is needed, suggesting that PS-MS is especially suitable for high-throughput analysis.

Qualitative and quantitative detection of honey adulterated with high-fructose corn syrup and maltose syrup by using near-infrared spectroscopy.

Near-infrared spectroscopy (NIR) was used for qualitative and quantitative detection of honey adulterated with high-fructose corn syrup (HFCS) or maltose syrup (MS). Competitive adaptive reweighted sampling (CARS) was employed to select key variables. Partial least squares linear discriminant analysis (PLS-LDA) was adopted to classify the adulterated honey samples. The CARS-PLS-LDA models showed an accuracy of 86.3% (honey vs. adulterated honey with HFCS) and 96.1% (honey vs. adulterated honey with MS), respectively. PLS regression (PLSR) was used to predict the extent of adulteration in the honeys. The results showed that NIR combined with PLSR could not be used to quantify adulteration with HFCS, but could be used to quantify adulteration with MS: coefficient (Rp2) and root mean square of prediction (RMSEP) were 0.901 and 4.041 for MS-adulterated samples from different floral origins, and 0.981 and 1.786 for MS-adulterated samples from the same floral origin (Brassica spp.), respectively.

[Qualitative and quantitative detection of beet syrup adulteration of honey by near-infrared spectroscopy: a feasibility study].

In order to further investigate the utility of near-infrared spectroscopys (NIRS) in rapidly detecting honey adulteration, near-infrared spectroscopy in combination with chemometric methods was investigated for qualitative and quantitative detection of beet syrup adulteration of honey. Total prediction accuracy of testing set was 90.2% by partial least squares-discriminant analysis (PLS-DA) for authentic and adulterated honey samples. Total prediction accuracy of testing sets was all below 33.3% by different discriminant methods for classes of adulteration level. The quantitative analysis of adulteration level by PLS regression gave satisfying results if adulterated honey samples were got from the same one authentic honey sample: correlation coefficient (r)of actual values versus predicted values was 0.9829 and root mean square error of prediction (RMSEP) was 1.394 2 in testing set, otherwise it gave dissatisfying results for the adulterated samples from different botanical origins or the different samples of the same botanical origins. The results showed that NIRS could be applied for rapid detection of authentic and adulterated honey samples, but not for detection of classes of adulteration level and quantification of adulteration level with beet syrup.

[Extraction and determination of essential oils in Indocalamus latifolius leaves and Indocalamus tessellatus leaves].

Indocalamus leaves are the generic name of the leaves of Indocalamus (Graminales) plants. The essential oils in Indocalamus latifolius leaves and Indocalamus tessellatus leaves were extracted by steam distillation method. Ether was used as the solvent to extract volatile compounds many times. Both the volatile compounds in Indocalamus latifolius leaves and Indocalamus tessellatus leaves were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that thirty-seven compounds were identified for the essential oils extracted from Indocalamus latifolius leaves, and its main components were found to be 3-hexen-1-ol, (Z)-; 1-hexanol; benzyl alcohol; hexanal; furan, 2-ethyl-; 3-buten-2-one, 4-(2,6, 6-trimethyl-1-cyclohexen-1-yl), (E)-; etc. Forty-nine components were identified for the essential oils extracted from Indocalamus tessellatus leaves, and its main components were found to be 3-hexen-1-ol, (Z)-; benzyl alcohol; 3-buten-2-one, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-, (E)-; 2-hexenal; phenylethyl alcohol, 2-methoxy-4-vinylphenol; furan, 2-ethyl-; etc. 3-Hexen-1-ol, (Z)- was the most abundant compound in the essential oils from both Indocalamus leaves. There were ketone, aldehyde, alcohol, phenol and ester in them. The contents of ketones, aldehydes, and alcohols were found higher than those of other compounds in the two essential oils.