Robust construction of konjac glucomannan/polylactic acid nanofibrous films incorporated with carvacrol via microfluidic blow spinning for food packaging

In recent years, the application of biopolymer-based nanofibers prepared via microfluidic blow spinning (MBS) for food packaging has continuously increased due to their advantages of biocompatibility, biodegradability, and safety. However, the poor spinnability, undesirable water barrier capacity, and loss of antibacterial and antioxidant properties of biopolymer-based nanofibers strictly restrict their real-world applications. In this work, carvacrol (CV) incorporated konjac glucomannan (KGM)/polylactic acid (PLA) nanofibrous films (KP-CV) were produced by MBS. The FTIR spectra and XRD analysis revealed the hydrogen bonding interactions among CV, PLA, and KGM, thus significantly improving the TS of KP-CV nanofibrous films from 0.23 to 1.27 MPa with increased content of CV from 0 % to 5 %. Besides, KP-CV nanofibrous films showed improved thermal stability, excellent hydrophobicity (WCA: 128.19°, WVP: 1.02 g mm/m2 h kPa), and sustained release of CV combined with good antioxidant activities (DPPH radical scavenging activity: 77.51 ± 1.57 %), and antibacterial properties against S. aureus (inhibition zone: 26.33 mm) and E. coli (inhibition zone: 22.67 mm). Therefore, as prepared KP-CV nanofibrous films can be potentially applied as packaging materials for the extended shelf life of cherry tomatoes.

Pullulan nanofibrous films incorporated with W/O emulsions via microfluidic solution blow spinning technology

In this work, pullulan (PUL) nanofibrous films incorporated with water-in-oil emulsions (PE) were prepared by microfluidic blowing spinning (MBS). The microstructures of nanofibers were characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR), and X-ray diffraction (XRD). With the addition of W/O emulsions, the thermal stability, mechanical, and water barrier properties of PUL nanofibers were improved. Increases in emulsion content significantly affected the antioxidant and antimicrobial properties of nanofibrous films. ABTS and DPPH free radical scavenging rates increased from 10.26 % and 8.57 % to 60.66 % and 57.54 %, respectively. The inhibition zone of PE nanofibers against E. coli and S. aureus increased from 11.00 to 20.00 and from 15.67 to 21.17 mm, respectively. In addition, we investigated the freshness effectiveness of PE nanofibrous films on fresh-cut apples. PE nanofibrous films significantly maintained the firmness, and reduced the weight loss and browning index of the fresh-cut apple, throughout the 4 days of storage. Thus, the PE nanofibrous films exhibited good potential to prolong the shelf life of fresh-cut fruit and promote the development of active food packaging.

Electrospun Konjac Glucomannan/Polyvinyl Alcohol Long Polymeric Filaments Incorporated with Tea Polyphenols for Food Preservations

In this study, nanofiber films were prepared by electrospinning technology with polyvinyl alcohol (PVA) and konjac glucomannan (KGM) as raw materials. Tea polyphenols (TPs) were incorporated in the above matrix, which increased physicochemical (thermal and mechanical characteristics) and antibacterial properties of the nanofiber films. The release behavior of phenolic compounds from PVA/KGM-TPs nanofiber films was determined in different food simulants; antioxidant and antibacterial activity of the films were also evaluated. The results showed that the addition of KGM increased the physical and chemical properties of the films. The tensile strength (TS) and elongation at break (EB) increased from 5.40 ± 0.33 to 10.62 ± 0.34 and from 7.24 ± 0.32 to 18.10 ± 0.91, respectively. PVA/KGM-TPs nanofiber films performed controlled release of TPs, with final release of 49.17% in 3% acetic acid, 43.6% in 10% ethanol, and 59.42% in 95% ethanol. The nanofiber films showed good antioxidation properties, with the free radical scavenging rate increasing from 1.33% to 25.61%, and good antibacterial properties with inhibition zones against E. coli and S. aureus of 24.33 ± 0.47 mm and 34.33 ± 0.94 mm, respectively. In addition, the as-prepared films showed significant preservation performance for raw bananas at 25 °C.

Biosynthesis of Quercetin-Loaded Melanin Nanoparticles for Improved Antioxidant Activity, Photothermal Antimicrobial, and NIR/pH Dual-Responsive Drug Release

Quercetin (QCT) is a promising dose-dependent nutraceutical that usually suffers from poor water solubility and low bioavailability issues. In this work, a novel QCT-loaded nanoscale delivery system was constructed based on the oxidative self-polymerization of melanin (Q@MNPs). The FT-IR, XRD, and Zeta potential analyses confirmed that QCT was successfully absorbed on the melanin nanoparticles (MNPs) via Π-Π and hydrogen bonding interactions. The encapsulation efficiency and particle size of Q@MNPs were 43.78% and 26.68 nm, respectively. Q@MNPs improved the thermal stability of QCT and the antioxidant properties in comparison to MNPs. Meanwhile, Q@MNPs presented fantastic photothermal conversion capacity and stability triggered by the NIR laser, which significantly enhanced the antibacterial capability with a sterilization rate of more than 98% against E. coli and S. aureus. More importantly, Q@MNPs exhibited NIR/pH dual-responsive drug release behavior and good biocompatibility (at concentrations of < 100 μg/mL). Thus, Q@MNPs show promising prospects for flavonoid delivery.

Highly Hydrophobic Gelatin Nanocomposite Film Assisted by Nano-ZnO/(3-Aminopropyl) Triethoxysilane/Stearic Acid Coating for Liquid Food Packaging

Biodegradable gelatin (G) food packaging films are in increasing demand as the substitution of petroleum-based preservative materials. However, G packaging films universally suffer from weak hydrophobicity in practical applications. Constructing a hydrophobic micro/nanocoating with low surface energy is an effective countermeasure. However, the poor compatibility with the hydrophilic G substrate often leads to the weak interfacial adhesion and poor durability of the hydrophobic coating. To overcome this obstacle, we used (3-aminopropyl) triethoxysilane (APS) as an interfacial bridging agent to prepare a highly hydrophobic, versatile G nanocomposite film. Specifically, tannic acid (TA)-modified nanohydroxyapatite (n-HA) particles (THA) were introduced in G matrix (G-THA) to improve the mechanical properties. Micro/nanostructure with low surface energy composed of nanozinc oxide (Nano-ZnO)/APS/stearic acid (SA) (NAS) was constructed on the surface of G-THA film (G-THA/NAS) through one-step spray treatment. Consequently, as-prepared G-THA/NAS film presented excellent mechanics (tensile strength: 7.6 MPa, elongation at break: 292.7%), water resistance ability (water contact angle: 150.4°), high UV-shielding (0% transmittance at 200 nm), degradability (100% degradation rate after buried in the natural soil for 15 days), antioxidant (78.8% of 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity), and antimicrobial (inhibition zone against Escherichia coli: 15.0 mm and Staphylococcus aureus: 16.5 mm) properties. It should be emphasized that the bridging function of APS significantly improves the interfacial adhesion ability of the NAS coating with more than 95% remaining area after the cross-cut adhesion test. Meanwhile, the G-THA/NAS film could maintain stable and long-lasting hydrophobic surfaces against UV radiation, high temperature, and abrasion. Based on these multifunctional properties, the G-THA/NAS film was successfully applied as a liquid packaging material. To sum up, we provide a feasible and effective method to prepare high-performance green packaging films.

Konjac glucomannan/carboxymethyl chitosan film embedding gliadin/casein nanoparticles for grape preservation

Constructing biopolymer-based packaging films with fantastic water resistance and mechanical properties for food preservation is highly desirable and challenging. In this work, Gliadin/Casein nanoparticles (GCNPs) were prepared by pH-driven method and embedded into konjac glucomannan/carboxymethyl chitosan (KC) film matrix to improve the water resistance and mechanical properties of KC film. Gliadin and Casein showed good compatibility and co-assembled to form compact GCNPs clusters through hydrogen bonding and hydrophobic interaction verified by FT-IR spectroscopy, and fluorescence spectroscopy. The particle size and zeta potential of GCNPs was 269.7 nm and -7.6 mV, respectively. The effect of GCNPs on the mechanics, water barrier, thermal stability, and UV-shielding of KC-GCNPs film was investigated. SEM images revealed that GCNPs uniformly distributed into KC film matrix and significantly improved the mechanics (tensile strength: 75.6 MPa, elongation at breaking: 36.7 %), water barrier ability (water contact angle: 91.3°, water vapor permeability: 0.994 g mm/m2 day kPa, water solubility: 52.0 %), thermal stability and UV blocking property of KC-GCNPs film. Furthermore, KC-GCNPs film could also be applied to extend the shelf life of grapes. This paper demonstrated the great potential of GCNPs as functional nanofillers in enhancing the physicochemical properties of KC film.

[Investigation and analysis of occupational hazard factors in different industries in Tongliao City]

Objective: To investigate the occupational hazard factors of different industries in Tongliao City, and to provide scientific basis for the prevention and control of occupational disease in Tongliao City. Methods: In July 2021, the detection data of coal dust, silica dust, cement dust, benzene, noise and other occupational hazard factors, as well as the occupational health examination data of workers in various positions of 104 enterprises in different industries in Tongliao City were cllected and anylazed. χ(2) test was used to analyze the results of chest radiography of workers in different age groups. Results: A total of 104 enterprises were investigated, and the median time-weighted average concentration (C(TWA)) of coal dust, silic a dust, cement dust and benzene in contact with test posts were 0.94, 0.30, 0.70 and 0.95 mg/m(3), respectively. The median 8 h equivalent sound level (L(EX, 8 h)) of noise was 74.1 dB (A) . The over standard rates of silica dust, cement dust and noise contact positions were 10.83% (16/240) , 7.14% (2/28) and 0.48% (3/628) , respectively. The differences of chest X-ray examination of coal dust and silica dust workers in different working ages were statistically significant (χ(2)=218.50, 531.80, P<0.001) . The difference of hearing threshold of noise workers with different working age was statistically significant (χ(2)=1290.00, P<0.001) . The rates of leukopenia and neutropenia were 41.90% (44/105) and 20.95% (22/105) in benzene exposed workers. The positive rate of brucella exposure workers was 1.33% (1/75) for tiger red plate agglutination test and 3.23% (3/93) for tube agglutination test. Conclusion: Silica dust, cement dust and noise exceed the standard in some posts and places in the Tongliao City, and some workers are infected with Brucella. In the future, we can focus on monitoring noise-generating posts, strengthen supervision and implement prevention and control measures to reduce the incidence of occupational diseases.

Multi-functional konjac glucomannan/chitosan bilayer films reinforced with oregano essential oil loaded β-cyclodextrin and anthocyanins for cheese preservation

In this work, a multifunctional bilayer film was prepared by solvent casting method. Elderberry anthocyanins (EA) were incorporated into konjac glucomannan (KGM) film as the inner indicator layer (KEA). β-cyclodextrin (β-CD) loaded with oregano essential oil (OEO) inclusion complexes (β-CD@OEO) was prepared and incorporated into chitosan (CS) film as the outer hydrophobic and antibacterial layer (CS-β-CD@OEO). The impacts of β-CD@OEO on the morphological, mechanical, thermal, water vapor permeability and water resistance properties, pH sensitivity, antioxidant, and antibacterial activities of bilayer films were thoroughly evaluated. The incorporation of β-CD@OEO into bilayer films can significantly improve the mechanical properties (tensile strength (TS): 65.71 MPa and elongation at break (EB): 16.81 %), thermal stability, and water resistance (Water contact angle (WCA): 88.15°, water vapor permeability (WVP): 3.53 g mm/m² day kPa). In addition, the KEA/CS-β-CD@OEO bilayer films showed color variations in acid-base environments, which could be used as pH-responsive indicators. The KEA/CS-β-CD@OEO bilayer films also presented controlled release of OEO, good antioxidant, and antimicrobial activity, which exhibited good potential for the preservation of cheese. To sum up, KEA/CS-β-CD@OEO bilayer films have potential applications in the field of food packaging industry.

Development of chitosan/konjac glucomannan/tragacanth gum tri-layer food packaging films incorporated with tannic acid and ε-polylysine based on mussel-inspired strategy

Constructing biodegradable food packaging with good mechanics, gas barrier and antibacterial properties to maintain food quality is still challenge. In this work, mussel-inspired bio-interface emerged as a tool for constructing functional multilayer films. Konjac glucomannan (KGM) and tragacanth gum (TG) with physical entangled network are introduced in the core layer. Cationic polypeptide ε-polylysine (ε-PLL) and chitosan (CS) producing cationic-π interaction with adjacent aromatic residues in tannic acid (TA) are introduced in the two-sided outer layer. The triple-layer film mimics the mussel adhesive bio-interface, where cationic residues in outer layers interact with negatively charged TG in the core layer. Furthermore, a series of physical tests showed excellent performance of triple-layer film with great mechanical properties (tensile strength (TS): 21.4 MPa, elongation at break (EAB): 7.9 %), UV-shielding (almost 0 % UV transmittance), thermal stability, water, and oxygen barrier (oxygen permeability (OP): 1.14 × 10^-3 g/m s Pa and water vapor permeability (WVP): 2.15 g mm/m² day kPa). In addition, the triple-layer film demonstrated advanced degradability, antimicrobial functions, and presented good moisture-proof performance for crackers, which can be potentially applied as dry food packaging.

Robust microfluidic construction of polyvinyl pyrrolidone microfibers incorporated with W/O emulsions stabilized by amphiphilic konjac glucomannan

In this work, we prepared polyvinyl pyrrolidone (PVP) microfibers incorporated water-in-oil (W/O) emulsions. The W/O emulsions were fabricated by hexadecyl konjac glucomannan (HKGM, emulsifier), corn oil (oil phase) and purple corn anthocyanins (PCAs, water phase). The structures and functions of emulsions and microfibers were characterized by confocal laser scanning (CLSM) and scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and nuclear magnetic resonance (NMR) spectroscopy. The results showed that W/O emulsions exhibited good storage stability for 30 d. Microfibers presented ordered and uniform arrays. Compared with pure PVP microfiber films, the addition of W/O emulsions with PCAs improved the water resistance (WVP from 1.28 to 0.76 g mm/m² day kPa), mechanical strength (Elongation at break from 18.35 % to 49.83 %), antioxidation (free radical scavenging rate from 2.58 % to 16.37 %), and antibacterial activity (inhibition zone against E. coli: 27.33 mm and inhibition zone against S. aureus: 28.33 mm) of microfiber films. Results showed that microfiber film exhibited controlled release of PCAs in W/O emulsions, and about 32 % of the PCAs were released from the microfiber film after 340 min. The as-prepared microfiber films exhibited potential applications for food packaging.

[The role of Keap1/Nrf2/HO-1 signal pathway in liver injury induced by rare earth neodymium oxide in mice]

Objective: To investigate the role of Keap1/Nrf2/HO-1 signaling pathway in liver injury induced by neodymium oxide (Nd(2)O(3)) in mice. Methods: In March 2021, forty-eight SPF grade healthy male C57BL/6J mice were randomly divided into control group (0.9% NaCl), low dose group (62.5 mg/ml Nd(2)O(3)), medium dose group (125.0 mg/ml Nd(2)O(3)), and high dose group (250.0 mg/ml Nd(2)O(3)), each group consisted of 12 animals. The infected groups were treated with Nd(2)O(3) suspension by non-exposed tracheal drip and were killed 35 days after dust exposure. The liver weight of each group was weighed and the organ coefficient was calculated. The content of Nd(3+) in liver tissue was detected by inductively coupled plasma mass spectrometry (ICP-MS). HE staining and immunofluorescence was used to observe the changes of inflammation and nuclear entry. The mRNA expression levels of Keap1, Nrf2 and HO-1 in mice liver tissue were detected by qRT-PCR. Western blotting was used to detect the protein expression levels of Keap1 and HO-1. The contents of catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) were detected by colorimetric method. The contents of interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were determined by ELISA. The data was expressed in Mean±SD. Two-independent sample t-test was used for inter-group comparison, and one-way analysis of variance was used for multi-group comparison. Results: Compared with the control group, the liver organ coefficient of mice in medium and high dose groups were increased, and the Nd(3+) accumulation in liver of mice in all dose groups were significantly increased (P<0.05). Pathology showed that the structure of liver lobules in the high dose group was slightly disordered, the liver cells showed balloon-like lesions, the arrangement of liver cell cords was disordered, and the inflammatory exudation was obvious. Compared with the control group, the levels of IL-1β and IL-6 in liver tissue of mice in all dose groups were increased, and the levels of TNF-α in liver tissue of mice in high dose group were increased (P<0.05). Compared with the control group, the mRNA and protein expression levels of Keap1 in high dose group were significantly decreased, while the mRNA expression level of Nrf2, the mRNA and protein expression levels of HO-1 were significantly increased (P<0.05), and Nrf2 was successfully activated into the nucleus. Compared with the control group, the activities of CAT, GSH-Px and T-SOD in high dose group were significantly decreased (P<0.05) . Conclusion: A large amount of Nd(2)O(3) accumulates in the liver of male mice, which may lead to oxidative stress and inflammatory response through activation of Keap1/Nrf2/HO-1 signal pathway. It is suggested that Keap1/Nrf2/HO-1 signal pathway may be one of the mechanisms of Nd(2)O(3) expose-induced liver injury in mice.

[Effects of Nd(2)O(3) exposure of rare earth particles on C57 BL/6J male mice sex hormone secretion and CYP11A1/PLZF/STRA8 protein expression]

Objective: To explore the effects of Nd(2)O(3) exposure to rare earth particles on the secretion of sex hormones, cytochrome P450 family member 11A1 (CYP11A1) , spermatogenesis markers promyelocytic leukemia zinc finger protein (PLZF) and retinoic acid stimulating gene 8 (STRA8) protein in C57 BL/6J male mice. Methods: In March 2021, Forty-eight male C57 BL/6J mice aged 6-8 weeks divided into control group and Nd(2)O(3) exposure low, medium and high dose groups (exposing doses of 62.5, 125.0, 250.0 mg/ml Nd(2)O(3)) , 12 per group. The mice in the Nd(2)O(3) groups were perfused with different doses of Nd(2)O(3) suspension by a one-time non-exposing tracheal instillation method, and the control group was perfused with an equal volume of normal saline, with a volume of 0.1 ml, to establish a mouse reproductive function injury model. After 28 days of exposure, the mice's body weight, testes and epididymis were weighed, and the organ coefficients were calculated; the two epididymis were taken to make a sperm suspension to determine the sperm count, survival rate, and deformity rate; inductively coupled plasma mass spectrometry (ICP-MS) method was used to detect the content of Nd in mouse testis tissue; HE staining was used to detect testicular tissue pathological changes and quantitative analysis; enzyme-linked immunosorbent assay (ELISA) method was used to detect serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) and testosterone (T) content; western blot was used to detect the protein levels of CYP11A1, PLZF and STRA8 in testicular tissues. Results: Compared with the control group, with the increase of the exposure dose, the Nd content in the testis of the mice showed an increasing trend, the sperm survival rate and LH showed a decreasing trend, and the sperm deformity rate showed an increasing trend (P<0.05) ; Pathological showed that the number of sperm in the seminiferous tubules of the testicular tissue in the Nd(2)O(3) medium and high dose groups was significantly reduced, and the germinal epithelial disintegration, intraepithelial vacuolization, and exfoliation of spermatogenic cells and supporting cells occurred; The height of germinal epithelium was significantly reduced, and the percentage of damaged seminiferous tubules showed an increasing trend (P<0.05) ; FSH and T levels in serum in the middle and high dose groups of Nd(2)O(3), and CYP11A1, PLZF and STRA8 proteins in testicular tissues showed a downward trend with increasing dose (P<0.05) . Conclusion: The rare earth particulate Nd(2)O(3) may interfere with the expression of CYP11A1, PLZF and STRA8 protein, thereby causing the disorder of sex hormone secretion in the body, the maintenance of spermatogonia and the obstruction of the process of meiosis, causing reproductive function damage.

Recent Trends of Microfluidics in Food Science and Technology: Fabrications and Applications

The development of novel materials with microstructures is now a trend in food science and technology. These microscale materials may be applied across all steps in food manufacturing, from raw materials to the final food products, as well as in the packaging, transport, and storage processes. Microfluidics is an advanced technology for controlling fluids in a microscale channel (1~100 μm), which integrates engineering, physics, chemistry, nanotechnology, etc. This technology allows unit operations to occur in devices that are closer in size to the expected structural elements. Therefore, microfluidics is considered a promising technology to develop micro/nanostructures for delivery purposes to improve the quality and safety of foods. This review concentrates on the recent developments of microfluidic systems and their novel applications in food science and technology, including microfibers/films via microfluidic spinning technology for food packaging, droplet microfluidics for food micro-/nanoemulsifications and encapsulations, etc.

Stable O/W emulsions and oleogels with amphiphilic konjac glucomannan network: preparation, characterization, and application

BACKGROUND

The stabilization of oil-in-water (O/W) emulsions has long been explored. Assembly of polymer networks is an effective method for stabilizing O/W emulsions. Konjac glucomannan (KGM) is a plant polysaccharide and the network of KGM gel is a good candidate for stabilizing O/W emulsions based on its high viscosity and thickening properties. However, natural KGM has strong hydrophilicity and is not able to offer interfacial activity. Octenyl succinic anhydride (OSA) is a hydrophobic molecule, which is widely used as thickener and stabilizer in food emulsions. In this work, the amphiphilic biopolymer (OSA-KGM) was fabricated by modifying the KGM with OSA. Furthermore, OSA-KGM biopolymer was used to prepare O/W emulsions, which were then freeze-dried and used to prepare oleogels as fat substitute for bakery products.

RESULTS

OSA-KGM had advanced hydrophobicity with water contact angle 81.13° and adsorption behavior at the oil-water interface, with interfacial tension decreasing from 18.52 to 13.57 mN m^-1 within 1 h. The emulsification of OSA-KGM remarkably improved the stability of emulsions without phase separation during storage for 31 days. Oleogels with OSA-KGM showed good thixotropic and structure recovery properties (approximately 100%) and low oil loss (from 69.5% to 50.4%). Cakes made from oleogels had a softer texture than cakes made from peanut oil and margarine.

CONCLUSION

Amphiphilic biopolymer OSA-KGM shows advanced interfacial activity and hydrophobicity. This paper provides an insight into preparing stable O/W emulsions with a new biopolymer and oleogels potentially applied as fat substitute in bakery products. © 2022 Society of Chemical Industry.

Chitosan films with tunable droplet size of Pickering emulsions stabilized by amphiphilic konjac glucomannan network

In this work, chitosan (CS) emulsion films were prepared with grapefruit essential oil (GEO) Pickering emulsions (OGEOs) stabilized by amphiphilic octenyl succinic anhydride (OSA) konjac glucomannan (OSA-KGM) network. The droplet size of emulsion was regulated by altering oil content in OGEOs (10 %, 20 %, 30 % and 40 %, w/w). The structural and physicochemical properties of CS films with tunable emulsion droplets (OGEOs) were investigated. The droplet size of OGEOs increased with the increasing content of GEO. FT-IR revealed that the formation of CS-OGEOs films was attributed to hydrogen bonding. CS-OGEOs films with large droplets presented smoother surface, enhanced water resistance, UV-shielding property, mechanical properties, but increased water vapor permeability (WVP) compared with CS-OGEOs films with small droplets. In addition, CS-OGEOs films with large droplets also presented compact film structure, controlled release of GEO, high efficiency of DPPH free radical scavenging and antibacterial activity. To sum up, incorporation of emulsion droplets was a good strategy for improving the structural and physicochemical properties of CS films.

[Research progress on the regulatory mechanism of non-coding RNA in arsenic toxicity]

Arsenic is a non-metallic element, and the International Agency for Research on Cancer has identified arsenic and its compounds as carcinogens. Arsenic and its compounds can be absorbed through the respiratory tract, skin and digestive tract, distributed in the liver, kidney, lung and skin, and cause damage. Non-coding RNAs are closely related to arsenic-induced nervous system disorders, cell necrosis, reproductive toxicity, and carcinogenesis. In recent years, the network regulation of microRNAs (miRNAs) , long non-coding RNAs (lncRNAs) , and circular RNAs (circRNAs) among non-coding RNAs in various diseases induced by arsenic has become a new research field. This paper summarizes the existing scientific research results, and expounds the mechanism of miRNAs, lncRNAs and circRNAs in arsenic toxicity, and provides basic data and theoretical basis for the prevention and treatment of arsenic poisoning.

Construction of Konjac Glucomannan/Oxidized Hyaluronic Acid Hydrogels for Controlled Drug Release

Konjac glucomannan (KGM) hydrogel has favorable gel-forming abilities, but its insufficient swelling capacity and poor control release characteristics limit its application. Therefore, in this study, oxidized hyaluronic acid (OHA) was used to improve the properties of KGM hydrogel. The influence of OHA on the structure and properties of KGM hydrogels was evaluated. The results show that the swelling capacity and rheological properties of the composite hydrogels increased with OHA concentration, which might be attributed to the hydrogen bond between the KGM and OHA, resulting in a compact three-dimensional gel network structure. Furthermore, epigallocatechin gallate (EGCG) was efficiently loaded into the KGM/OHA composite hydrogels and liberated in a sustained pattern. The cumulative EGCG release rate of the KGM/OHA hydrogels was enhanced by the increasing addition of OHA. The results show that the release rate of composite hydrogel can be controlled by the content of OHA. These results suggest that OHA has the potential to improve the properties and control release characteristics of KGM hydrogels.

[Clinical characteristics of silent pheochromocytoma]

Objective: To summarize the clinical characteristics of silent paraganglioma. Methods: A total of 247 pheochromocytoma cases in Peking University First Hospital between January 1993 and December 2015 were analyzed retrospectively.The cases were divided into two groups according to whether they had hypertension: non-silent group (193 cases) and silent group (53 cases), then the clinical characteristics between the groups were compared, and the clinical features of silent pheochromocytoma were reviewed. Results: There were 53 silent pheochromocytoma cases in this study, which accounted for 21.5% (53/247), and imaging was the main way to find the tumor. Forty-one in 53 cases (77.4%) located in adrenal gland, in which 31 cases (75.6%) were benign and 2.3-8.0 cm in diameter, while 10 cases (24.4%) were malignant and 3.5-12.0 cm in diameter. Twelve in 53 cases (22.6%) located in extra-adrenal tissue, in which 4 cases were benign and 2.0-5.5 cm in diameter, while 8 cases were malignant and 5.0-10.5 cm in diameter. With the tumor diameter increased, the malignant rate increased: 1 in 8 cases in diameter<3 cm, 2 in 12 cases in diameter 3-5 cm, 15 in 33 cases in diameter>5 cm were malignant. There was no significant difference in age, sex, tumor location, benign or malignant rate between the two groups (all P>0.05). Compared with the non-silent group, the proportion of tumor size≥5 cm in silent group was significantly higher (62.3% vs 45.9%, P=0.034), and the incidence of hyperglycemia and the concentrations of norepinephrine and epinephrine were lower (all P<0.05) in silent group.Misdiagnosis was common in silent group, and up to 35.8% (19/53) had not been diagnosed correctly before operation. Twenty-one in 53 (39.6%) silent pheochromocytoma cases occured severe intra-operative blood pressure fluctuation. Conclusions: Silent pheochromocytoma was not uncommon and imaging was the main way to find it. The tumor size was always big and misdiagnosis was common, especially extra-adrenal tumors. Therefore, regardless of the adrenal or extra-adrenal tumors, especially in diameter>3.0 cm but with normal blood pressure, the possibility of silent pheochromocytoma should be considered. In order to reduce misdiagnosis and intra-operative blood pressure fluctuations, preoperative diagnosis and preparation, as well as intra-operative monitoring should be fully made.

Coexistence of perfect spin filtering for entangled electron pairs and high magnetic storage efficiency in one setup

For Entangled electron pairs superconducting spintronics, there exist two drawbacks in existing proposals of generating entangled electron pairs. One is that the two kinds of different spin entangled electron pairs mix with each other. And the other is a low efficiency of entanglement production. Herein, we report the spin entanglement state of the ferromagnetic insulator (FI)/s-wave superconductor/FI structure on a narrow quantum spin Hall insulator strip. It is shown that not only the high production of entangled electron pairs in wider energy range, but also the perfect spin filtering of entangled electron pairs in the context of no highly spin-polarized electrons, can be obtained. Moreover, the currents for the left and right leads in the antiferromagnetic alignment both can be zero, indicating 100% tunnelling magnetoresistance with highly magnetic storage efficiency. Therefore, the spin filtering for entangled electron pairs and magnetic storage with high efficiencies coexist in one setup. The results may be experimentally demonstrated by measuring the tunnelling conductance and the noise power.

Genotoxicity of fenpropathrin and fenitrothion on root tip cells of Vicia faba

The genotoxicity of fenpropathrin and fenitrothion on root tip cells of Vicia faba was studied. The symptoms were investigated about the mitotic index, the micronucleus frequency and chromosomal aberration frequency of root tip cells of Vicia faba which were induced by different concentrations of fenpropathrin and fenitrothion (1 × 10(-10)-1 × 10(-2) g L(-1)). Results showed that fenpropathrin and fenitrothion could induce the micronucleus of root tip cells of Vicia faba. It occurred in a dose-dependent manner. Peaks were observed at 1 × 10( -6) g L(-1) fenpropathrin and 1 × 10(-4) g L(-1) fenitrothion, and micronucleus frequency reached 14.587 ± 1.511‰ and 14.164 ± 1.623‰, respectively. From 1 × 10(-10) g L(-1) to 1 × 10( -6) g L(-1) fenpropathrin and 1 × 10(-4) g L(-1) fenitrothion, the micronucleus frequency increased with the increase of the concentrations, but beyond this range, the micronucleus frequency decreased with the further increase of the concentrations. A similar trend was observed for mitotic index. Moreover, fenpropathrin and fenitrothion could induce various types of chromosome aberration, such as lagging chromosomes, chromosome fragment, chromosome bridge, multipolar, nuclear buds, karyorrhexis, etc.

Alleviation effect of alginate-derived oligosaccharides on Vicia faba root tip cells damaged by cadmium

Cadmium has been shown to prevent Vicia faba growth by inhibiting cell mitosis. In this study we investigated the role of Alginate-derived Oligosaccharides (ADO) in alleviating Vicia faba root tip cells damaged by 6 and 8 mg L(-1) CdCl2. Micronucleus assay and chromosomal aberration assay were used to determine mitotic index, micronucleus frequency and chromosomal aberration frequency. The results showed that micronucleus frequency of Vicia faba root tip cells was inhibited under all the ADO concentrations. Especially, the inhibition ratio of 0.125% ADO highly reached 66.11 and 67.17% in 6 and 8 mg L(-1) CdCl2, respectively. Furthermore, the mitotic index increased (p < 0.05) and chromosomal aberration frequency decreased (p < 0.05) under all the ADO concentrations. This indicated that ADO had a significant alleviation effect on Vicia faba root tip cells damaged by cadmium.