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Objective Proximal humeral fracture combined with contralateral midshaft clavicle fracture is an extremely rare injury in children. Few studies focus on the injury mechanism and treatment scheme. The aim of this study is to propose the possible mechanism of this injury and present the treatment results. Methods This retrospective study included children diagnosed with proximal humeral fractures combined with contralateral midshaft clavicle fractures from August 2016 to March 2019 in the corresponding author's institution. The patients received elastic stable intramedullary nails and external fixation as treatment. The radiological and clinical outcomes of treatments were evaluated using the imaging and the Constant–Murley score (CMS) in follow up. Results Twelve patients (eight males and four females) with an average age of 7.83 years old (age 5–12) were included in this research. All the patients had suffered a side impact in a road traffic accident or outdoor environment. Hypothesis about the mechanism was the proximal humerus was directly impacted at first and caused the surgical neck fracture, then the contralateral shoulder hits the solid object and the contralateral midshaft clavicle was fractured. During the average 45.2 months (range 36–57) follow‐up, all the patient's fractures achieved clinical and radiological union before 14 weeks without complications. Every patient had a satisfactory score (range from 92 to 100) on the CMS criteria for both shoulders. Conclusion The hypothesis about the mechanism of this combined injury in this study sounds reasonable. It highlights the need for safety‐related education about using a safety seat or wearing a seat belt to parents and caregivers, so as to avoid such injury even if the treatment with external fixation (EF) and proximal humeral and elastic stable intramedullary nailing (ESIN) showed good results.

Objective Combined fractures of the lateral condyle of the humerus and the ipsilateral ulnar olecranon are rarely seen in children. Therefore, the mechanism and suitable treatments remain debatable. This study describes the possible mechanism of combined humeral lateral condyle and ipsilateral ulnar olecranon fractures and presents the treatment results. Methods Children diagnosed with combined fractures of the humeral lateral condyle and ipsilateralulnar olecranon from July 2010 to July 2020 were retrospectively analyzed. Humeral lateral condyle fractures were treated with open reduction and internal fixation with bioabsorbable pins. Ulnar olecranon fractures were treated with closed reduction and percutaneous pinning with K‐wires for Mayo type IA fractures and with tension‐band wiring or a locking plate for Mayo type IIA fractures. The postoperative function and appearance of the elbow were evaluated using the Flynn criteria and Mayo Elbow Performance Score (MEPS) at follow‐up. Results The cohort comprised 19 patients aged from 4 to 11 years. Bony compression and avulsion by attached muscles and ligaments may be the leading factors causing the combined injuries, as the children fell with an outstretched and supinated elbow. The average follow‐up time was 33 months. High MEPS of >90 indicated that good to excellent results were obtained without complications. Conclusions This study proposed a reasonable hypothesis for the mechanism of combined humeral lateral condyle and ipsilateral ulnar olecranon fractures in children. Satisfactory outcomes were achieved with bioabsorbable pins for lateral condyle fractures and closed reduction and percutaneous pinning with K‐wires, tension‐band wiring, or locking plate for olecranon fractures.

Abstract Activation of regeneration upon tissue damages requires the activation of many developmental genes responsible for cell proliferation, migration, differentiation, and tissue patterning. Ample evidence revealed that the regulation of chromatin organization functions as a crucial mechanism for establishing and maintaining cellular identity through precise control of gene transcription. The alteration of chromatin organization can lead to changes in chromatin accessibility and/or enhancer-promoter interactions. Like embryogenesis, each stage of tissue regeneration is accompanied by dynamic changes of chromatin organization in regeneration-responsive cells. In the past decade, many studies have been conducted to investigate the contribution of chromatin organization during regeneration in various tissues, organs, and organisms. A collection of chromatin regulators were demonstrated to play critical roles in regeneration. In this review, we will summarize the progress in the understanding of chromatin organization during regeneration in different research organisms and discuss potential common mechanisms responsible for the activation of regeneration response program.

IntroductionThis study aimed to determine the influence of red light on objective sleep and the relationship between mood and sleep among individuals with insomnia disorder (ID).Method57 individuals with insomnia symptoms and 57 healthy participants were randomly divided into three groups (red- and white-light groups, and the black control group), which received different light treatments for 1 h before bedtime. The emotions and subjective alertness of participants were evaluated using Positive and Negative Affect Schedule scales (PANAS) and Karolinska Sleepiness Scale (KSS), their sleeping data were recorded using polysomnography (PSG).ResultThe negative emotion scores were higher in the healthy subject-red light (HS-RL) group than in the HS-white light (WL) and HS-black control (BC) groups (p

The biochemical pathway regulating the synthesis of yellow/red pheomelanin is less well characterized than the synthesis of black/brown eumelanin. Inhibitor of gold (IG phenotype) is a plumage colour variant in chicken that provides an opportunity to further explore this pathway since the recessive allele (IG) at this locus is associated with a defect in the production of pheomelanin. IG/IG homozygotes display a marked dilution of red pheomelanin pigmentation, whilst black pigmentation (eumelanin) is only slightly affected. Here we show that a 2-base pair insertion (frame-shift mutation) in the 5th exon of the Catechol-O-methyltransferase containing domain 1 gene (COMTD1), expected to cause a complete or partial loss-of-function of the COMTD1 enzyme, shows complete concordance with the IG phenotype within and across breeds. We show that the COMTD1 protein is localized to mitochondria in pigment cells. Knockout of Comtd1 in a mouse melanocytic cell line results in a reduction in pheomelanin metabolites and significant alterations in metabolites of glutamate/glutathione, riboflavin, and the tricarboxylic acid cycle. Furthermore, COMTD1 overexpression enhanced cellular proliferation following chemical-induced transfection, a potential inducer of oxidative stress. These observations suggest that COMTD1 plays a protective role for melanocytes against oxidative stress and that this supports their ability to produce pheomelanin.

The impact of the gut microbiota on human physiology through their vast metabolic activities has surfaced as a remarkable scientific discovery over the past decade [...]

Background: In patients with traumatic brain injury (TBI) combined with long bone fracture, the fracture healing is always faster than that of patients with single fracture, which is characterized by more callus growth at the fracture site and even ectopic ossification. Exosomes are nanoscale membrane vesicles secreted by cells, which contain cell-specific proteins, miRNAs, and mRNAs. Methods: In this study, we used exosomes as the entry point to explore the mechanism of brain trauma promoting fracture healing. We established a model of tibia fracture with TBI in mice to observe the callus growth and expression of osteogenic factors at the fracture site. Blood samples of model mice were further collected, exosomes in plasma were extracted by ultra-centrifugation method, and then identified and acted on osteoblasts cultured in vitro. The effects of exosomes on osteoblast differentiation at the cell, protein and gene levels were investigated by Western Blot and q-PCR, respectively. Furthermore, miRNA sequencing of exosomes was performed to identify a pattern of miRNAs that were present at increased or decreased levels. Results: The results suggested that plasma exosomes after TBI had the ability to promote the proliferation and differentiation of osteoblasts, which might be due to the increased expression of osteoblast-related miRNA in exosomes. They were transmitted to the osteoblasts at the fracture site, so as to achieve the role of promoting osteogenic differentiation. Conclusion: The TBI-derived exosomes may have potential applications for promoting fracture healing in future. The Translational Potential of this Article: Plasma exosomes early after TBI have the ability to promote osteoblast proliferation and differentiation. The mechanism may be achieved by miRNA in exosomes. Plasma exosomes may be used as breakthrough clinical treatment for delayed or non-union fractures.

BackgroundSupracondylar humeral fractures (SHF) are the most common type of fracture occurring at the distal humerus in children. In patients with delayed presentation of SHF, closed reduction is challenging to achieve with traditional reduction maneuvers. This study aimed to report the clinical results of pediatric SHF delayed over 14 days treated by closed reduction with a minimally invasive technique and external fixation and evaluate the efficacy of this technique.MethodsBetween October 2010 and September 2018, children with delayed presentation of SHF over 14 days were retrospectively included in this study. The patients received closed reduction with a minimally invasive technique followed by external fixation. The demographics and radiographic data were collected. The Mayo Elbow Performance Score (MEPS) and the Flynn criteria were used to evaluate the clinical outcomes of treatments.ResultsA total of 11 children (aged 4–13 years) with delayed presentation (range, 14–22 days) were recruited. They received surgery using closed reduction with a minimally invasive technique followed by external fixation. None of the surgery was done with the open method. After surgery, the patients' carrying angle returned to normal. The radiological union was evident in 8 to 12 weeks in all fractures without complications. Every patient had a good to excellent score on the MEPS and the Flynn criteria.ConclusionsThe results of this series indicated a satisfactory outcome in children with delayed more than 14 days of supracondylar humeral fractures. The closed reduction with a minimally invasive technique followed by external fixation is an alternative treatment for such injury.

Abstract Background Inflammatory osteolysis after total joint replacement (TJR) may cause implant failure, periprosthetic fractures, and be a severe threat to global public health. Our previous studies demonstrated that melatonin had a therapeutic effect on wear-particles induced osteolysis. Gut microbiota is closely related to bone homeostasis, and has been proven to be affected by melatonin. However, whether melatonin could play its anti-osteolysis effects through reprogramming gut microbiota remains elusive. Results Here, we demonstrated that melatonin could alleviate Ti-particles induced osteolysis, while this therapeutic effect was blocked by antibiotic cocktail treatment. Interestingly, transplantation of fecal microbiota from mice treated with melatonin reappeared the same beneficial effect. Analysis of the 16S rRNA revealed that melatonin could reverse dysbacteriosis triggered by osteolysis, and elevate the relative abundance of some short chain fatty acid (SCFA) producing bacteria. Moreover, butyrate was enriched by exogenous melatonin administration, while acetate and propionate did not show an evident difference. This was consistent with the results of the metagenomic approach (PICRUSt2) analysis, which revealed a general increase in the synthetic enzymes of butyrate. More importantly, direct supplementation of butyrate could also recapitulate the anti-osteolysis effect of melatonin. Further analysis identified that butyrate alleviated osteolysis via activating its receptor GPR109A, and thus to suppress the activation of NLRP3 inflammasome triggered by Ti-particles. Conclusions Taken together, our results suggested that the benefits of melatonin mainly depend on the ability of modulating gut microbiota and regulating butyrate production. Graphic Abstract

As a nonspecific protein adsorption material, a strong hydration layer provides zwitterionic hydrogels with excellent application potential while weakening the interaction between zwitterionic units, leading to poor mechanical properties. The unique anti-polyelectrolyte effect in ionic solution further restricts the application value due to the worsening mechanical strength. To overcome the limitations of zwitterionic hydrogels that can only be used in scenarios that do not require mechanical properties, several methods for strengthening mechanical properties based on enhancing intermolecular interaction forces and polymer network structure design have been extensively studied. Here, we review the works on preparing tough zwitterionic hydrogel. Based on the spatial and molecular structure design, tough zwitterionic hydrogels have been considered as an important candidate for advanced biomedical and soft ionotronic devices.

A dual-band base station antenna is introduced in this paper. The proposed antenna is composed of baluns, bowtie patches, and a split ring. The two pairs of bowtie patches excited by the two orthogonal balun structures can achieve dual polarization. The split ring is used to yield two additional resonances to broaden the impedance bandwidth. In this way, a compact dual-band base station antenna is obtained with the size of 0.41 λc × 0.41 λc × 0.13 λc (λc is the wavelength in the free space at the lowest operating frequency band) and the average gain of 8.2 dBi. Moreover, the operating frequency bands of the proposed antenna cover 2515–2675 MHz, 3400–3600 MHz, and 4800–5000 MHz, which can function as an element for macro- or microcells in sub-6 GHz communications.

Understanding the adsorption and interaction between porous materials and protein is of great importance in biomedical and interface sciences. Among the studied porous materials, TiO2 and its hybrid materials, featuring distinct, well-defined pore sizes, structural stability and excellent biocompatibility, are widely used. In this review, the use of four powerful, synergetic and complementary techniques to study protein-TiO2-based porous materials interactions at different scales is summarized, including high-performance liquid chromatography (HPLC), atomic force microscopy (AFM), surface-enhanced Raman scattering (SERS), and Molecular Dynamics (MD) simulations. We expect that this review could be helpful in optimizing the commonly used techniques to characterize the interfacial behavior of protein on porous TiO2 materials in different applications.

A compact hybrid-mode antenna is proposed for sub-6 GHz communication. The proposed antenna is composed of a slotted rectangular patch, a feeding dipole, and a balun. Three modes are sequentially excited in a shared patch to achieve a compact size. A prototype antenna with a major size of 0.48 λ0 × 0.31 λ0 × 0.16 λ0 (λ0 is the wavelength in the free space at the center of the operating frequency band) is fabricated and measured. The measured results demonstrate an impedance bandwidth of 56.87% from 2.97 GHz to 5.33 GHz and an average gain of approximately 8.00 dBi with 1 dB variation in the operating frequency band of 3.0–5.0 GHz. The proposed antenna can be an element for microbase stations in sub-6 GHz communication.

Blood cancers are a type of liquid tumor which means cancer is present in the body fluid. Multiple myeloma, leukemia, and lymphoma are the three common types of blood cancers. Chemotherapy is the major therapy of blood cancers by systemic administration of anticancer agents into the blood. However, a high incidence of relapse often happens, due to the low efficiency of the anticancer agents that accumulate in the tumor site, and therefore lead to a low survival rate of patients. This indicates an urgent need for a targeted drug delivery system to improve the safety and efficacy of therapeutics for blood cancers. In this review, we describe the current targeting strategies for blood cancers and recently investigated and approved drug delivery system formulations for blood cancers. In addition, we also discuss current challenges in the application of drug delivery systems for treating blood cancers.

Nonspecific protein adsorption impedes the sustainability of materials in biologically related applications. Such adsorption activates the immune system by quick identification of allogeneic materials and triggers a rejection, resulting in the rapid failure of implant materials and drugs. Antifouling materials have been rapidly developed in the past 20 years, from natural polysaccharides (such as dextran) to synthetic polymers (such as polyethylene glycol, PEG). However, recent studies have shown that traditional antifouling materials, including PEG, still fail to overcome the challenges of a complex human environment. Zwitterionic materials are a class of materials that contain both cationic and anionic groups, with their overall charge being neutral. Compared with PEG materials, zwitterionic materials have much stronger hydration, which is considered the most important factor for antifouling. Among zwitterionic materials, zwitterionic hydrogels have excellent structural stability and controllable regulation capabilities for various biomedical scenarios. Here, we first describe the mechanism and structure of zwitterionic materials. Following the preparation and property of zwitterionic hydrogels, recent advances in zwitterionic hydrogels in various biomedical applications are reviewed.

Osteoarthritis (OA) is the most prevalent degenerative joint disease affecting millions of people worldwide. Currently, clinical nonsurgical treatments of OA are only limited to pain relief, anti-inflammation, and viscosupplementation. Developing disease-modifying OA drugs (DMOADs) is highly demanded for the efficient treatment of OA. As OA is a local disease, intra-articular (IA) injection directly delivers drugs to synovial joints, resulting in high-concentration drugs in the joint and reduced side effects, accompanied with traditional oral or topical administrations. However, the injected drugs are rapidly cleaved. By properly designing the drug delivery systems, prolonged retention time and targeting could be obtained. In this review, we summarize the drugs investigated for OA treatment and recent advances in the IA drug delivery systems, including micro- and nano-particles, liposomes, and hydrogels, hoping to provide some information for designing the IA injected formulations.

Triple-negative breast cancer (TNBC) is characterized by extensive tumor heterogeneity at both the pathologic and molecular levels, particularly accelerated aggressiveness, and terrible metastasis. It is responsible for the increased mortality of breast cancer patients. Due to the negative expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2, the progress of targeted therapy has been hindered. Higher immune response in TNBCs than for other breast cancer types makes immunotherapy suitable for TNBC therapy. At present, promising treatments in immunotherapy of TNBC include immune checkpoints (ICs) blockade therapy, adoptive T-cell immunotherapy, and tumor vaccine immunotherapy. In addition, nanomedicines exhibit great potential in cancer therapy through the enhanced permeability and retention (EPR) effect. Immunotherapy-involved combination therapy may exert synergistic effects by combining with other treatments, such as traditional chemotherapy and new treatments, including photodynamic therapy (PTT), photodynamic therapy (PDT), and sonodynamic therapy (SDT). This review focuses on introducing the principles and latest development as well as progress in using nanocarriers as drug-delivery systems for the immunotherapy of TNBC.

Water soluble organic molecular pollution endangers human life and health. It becomes necessary to develop highly stable noble metal nanoparticles without aggregation in solution to improve their catalytic performance in treating pollution. Polyethyleneimine (PEI)-based stable micelles have the potential to stabilize noble metal nanoparticles due to the positive charge of PEI. In this study, we synthesized the amphiphilic PEI-oleic acid molecule by acylation reaction. Amphiphilic PEI-oleic acid assembled into stable PEI-oleic acid micelles with a hydrodynamic diameter of about 196 nm and a zeta potential of about 34 mV. The PEI-oleic acid micelles-stabilized palladium nanoparticles (PO-PdNPsn) were prepared by the reduction of sodium tetrachloropalladate using NaBH4 and the palladium nanoparticles (PdNPs) were anchored in the hydrophilic layer of the micelles. The prepared PO-PdNPsn had a small size for PdNPs and good stability in solution. Noteworthily, PO-PdNPs150 had the highest catalytic activity in reducing 4-nitrophenol (4-NP) (Knor = 18.53 s−1mM−1) and oxidizing morin (Knor = 143.57 s−1M−1) in aqueous solution than other previous catalysts. The enhanced property was attributed to the improving the stability of PdNPs by PEI-oleic acid micelles. The method described in this report has great potential to prepare many kinds of stable noble metal nanoparticles for treating aqueous pollution.

Insomnia is a type of sleep disorder which is associated with various diseases’ development and progression, such as obesity, type II diabetes and cardiovascular diseases. Recent investigation of the gut-brain axis enhances our understanding of the role of the gut microbiota in brain-related diseases. However, whether the gut microbiota is associated with insomnia remains unknown. In the present investigation, leveraging the 16S rDNA amplicon sequencing of V3-V4 region and the novel bioinformatic analysis, it was demonstrated that between insomnia and healthy populations, the composition, diversity and metabolic function of the gut microbiota are significantly changed. Other than these, redundancy analysis, co-occurrence analysis and PICRUSt underpin the gut taxa composition, signaling pathways, and metabolic functions perturbed by insomnia disorder. Moreover, random forest together with cross-validation identified two signature bacteria, which could be used to distinguish the insomnia patients from the healthy population. Furthermore, based on the relative abundance and clinical sleep parameter, we constructed a prediction model utilizing artificial neural network (ANN) for auxiliary diagnosis of insomnia disorder. Overall, the aforementioned study provides a comprehensive understanding of the link between the gut microbiota and insomnia disorder.

The sensitive and selective detection of dopamine (DA) is very important for the early diagnosis of DA-related diseases. In this study, we reported the colorimetric detection of DA using Ganoderma lucidum polysaccharide (GLP) stabilized platinum nanoclusters (Ptn-GLP NCs). When Pt600-GLP NCs was added, 3,3’,5,5’-tetramethylbenzidine (TMB) was rapidly catalyzed and oxidized to blue oxTMB, indicating the peroxidase-like activity of Pt600-GLP NCs. The catalytic reaction on the substrate TMB followed the Michaelis-Menton kinetics with the ping-pong mechanism. The mechanism of the colorimetric reaction was mainly due to the formation of hydroxyl radical (•OH). Furthermore, the catalytic reaction of Pt600-GLP NCs was used in the colorimetric detection of DA. The linear range for DA was 1–100 μM and the detection limit was 0.66 μM. The sensitive detection of DA using Pt-GLP NCs with peroxidase-like activity offers a simple and practical method that may have great potential applications in the biotechnology field.

Ascorbic acid is an organic compound with antioxidant properties that can protect the human body from the threat of free radicals. Therefore, it is important to detect the existence and measure the concentration of ascorbic acid to regulate its content in the human body. In this work, we prepared bitter gourd polysaccharide (BGP)-stabilized platinum nanoclusters (Pt-BGP NCs) by reacting BGP with K2PtCl4. Pt-BGP NCs and catalyzed the decomposition of H2O2 to generate •OH radicals, which could oxidize TMB to form oxidized TMB (oxTMB), indicating their peroxidase-like properties. The kinetics followed the Michaelis–Menten equation. Furthermore, the colorimetric detection of ascorbic acid using Pt-BGP NCs showed high selectivity and a low detection limit of 0.191 μM. The accuracy of real sample detection using Pt-BGP NCs was as high as 98.9%. More importantly, Pt-BGP NCs had high cell biocompatibility and extremely low hemolysis rate due to the component of BGP. In summary, the prepared Pt-BGP NCs with reductive activity and good biocompatibility have good application prospects in colorimetric detection of ascorbic acid.

Hydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. Among the ensemble of molecules acting in the joint, phosphatidylcholine (PC) lipids have been proposed as the key molecules forming, in a complex with other molecules including hyaluronic acid (HA), a robust layer on the outer surface of the cartilage. HA, ubiquitous in synovial joints, is not in itself a good boundary lubricant, but binds the PC lipids at the cartilage surface; these, in turn, massively reduce the friction via hydration lubrication at their exposed, highly hydrated phosphocholine headgroups. An important unresolved issue in this scenario is why the free HA molecules in the synovial fluid do not suppress the lubricity by adsorbing simultaneously to the opposing lipid layers, i.e., forming an adhesive, dissipative bridge between them, as they slide past each other during joint articulation. To address this question, we directly examined the friction between two hydrogenated soy PC (HSPC) lipid layers (in the form of liposomes) immersed in HA solution or two palmitoyl–oleoyl PC (POPC) lipid layers across HA–POPC solution using a surface force balance (SFB). The results show, clearly and surprisingly, that HA addition does not affect the outstanding lubrication provided by the PC lipid layers. A possible mechanism indicated by our data that may account for this is that multiple lipid layers form on each cartilage surface, so that the slip plane may move from the midplane between the opposing surfaces, which is bridged by the HA, to an HA-free interface within a multilayer, where hydration lubrication is freely active. Another possibility suggested by our model experiments is that lipids in synovial fluid may complex with HA, thereby inhibiting the HA molecules from adhering to the lipids on the cartilage surfaces.

A low-profile antenna with a high gain and broad bandwidth is proposed for Sub-6GHz communication in this paper. A narrow-band patch mode and a narrow-band dipole mode are shared in one radiator and simultaneously excited to broaden the bandwidth. A compact prototype with a projection size of 0.90 λ0 × 0.78 λ0 and a profile of 0.13 λ0 (λ0 is the wavelength in the free space at the center of the operating frequency) is fabricated and measured. The measurement demonstrates an impedance bandwidth of 67.50%, covering the frequency range from 2.75 GHz to 5.45 GHz and an average gain of 8.4 dBi in the operating band of 3.0–5.0 GHz.

In this study, we investigated the microbiota dynamics during two industrial-scale traditional solid-state fermentation (SSF) processes of Daqu starters. Similar evolution profiles of environmental parameters, enzymatic activities, microbial amounts and communities were observed during the medium temperature SSF (MTSSF) and low temperature SSF (LTSSF) processes. Orders of Rickettsiales and Streptophyta only dominated the initial two days, and Eurotiales only predominated from days 10 to 24, however, phylotypes of Enterobacteriales, Lactobacillales, Bacillales, Saccharomycetales and Mucorales both prevailed throughout the MTSSF and LTSSF processes. Nevertheless, the pH in MTSSF process on day 5 were 5.28, while in LTSSF process (4.87) significantly lower (P < 0.05). The glucoamylase activities in MTSSF process dropped from 902.71 to 394.33 mg glucose g-1 h-1 on days 5 to 24, while significantly lower (P < 0.05) in LTSSF process and decreased from 512.25 to 268.69 mg glucose g-1 h-1. The relative abundance of Enterobacteriales and Lactobacillales in MTSSF process constituted from 10.30% to 71.73% and 2.34% to 16.68%, while in LTSSF process ranged from 3.16% to 41.06% and 8.43% to 57.39%, respectively. The relative abundance of Eurotiales in MTSSF process on days 10 to 24 decreased from 36.10% to 28.63%, while obviously higher in LTSSF process and increased from 52.00% to 72.97%. Furthermore, lower bacterial richness but higher fungal richness were displayed, markedly differences in bacterial communities but highly similarities in fungal communities were exhibited, during MTSSF process comparatively to the LTSSF process. Canonical correspondence analysis revealed microbial structure transition happened at thermophilic stages under environmental stress of moisture, pH, acidity and pile temperature. These profound understanding might help to effectively control the traditional Daqu SSF process by adjusting relevant environmental parameters.

Discarded tobacco leaf protein hydrolysate (DTLPH) was prepared by enzymatic hydrolysis using papain and then separated using ultrafiltration (UF) membranes with molecular mass cut-off (MMCO) of 10, 5, 3 and 1 kDa. Four permeate fractions including 10-K, 5-K, 3-K and 1-K (the permeate fractions from 10, 5, 3 and 1 kDa) hydrolysate fractions were obtained. The 5-K hydrolysate fraction had high oxidation inhibilitory ratio (42.62 %), which was about twofold higher than the original hydrolysate and as high as that of vitamin E (α-tocopherol). The fractionated hydrolysates were superior to the original hydrolysate in the antioxidative activity tested. Moreover, these separated hydrolysates showed the enhanced functional property. The amino acid composition of 5-K hydrolysate was analyzed and the results show that the high antioxidative activity of 5-K hydrolysate was derived from high content of histidine, methionine, cystine and tryptophan.