Preparation of Environmentally Friendly Urea-Hexanediamine-Glyoxal(HUG)Resin Wood Adhesive

Using non-toxic,low-volatile glyoxal to completely replace formaldehyde for preparing urea-glyoxal(UG)resin adhesive is a hot research topic that could be of great interest for the wood industry.However,urea-glyoxal(UG)resins prepared by just using glyoxal instead of formaldehyde usually yields a lower degree of polymerization.This results in a poorer bonding performance and water resistance of UG resins.A good solution is to pre-react urea to preform polyurea molecules presenting already a certain degree of polymerization,and then to condense these with glyoxal to obtain a novel UG resin.Therefore,in this present work,the urea was reacted with hexamethylene diamine to form a polyurea named HU,and then this was used to react it with different amounts of glyoxal to synthesize hexamethylenediamine-urea-glyoxal(HUG)polycondensation resins,and to use this for bonding plywood.The results show that the glyoxal can well react with HU polyuria via addition and schiff base reaction,and also the HUG resin exhibits excellent bonding strength and water resistance.The shear strength of the plywood bonded with this HUG at 160°C hot press temperature as high as 1.93 MPa,2.16 MPa and 1.61 MPa,respectively,which meets the requirement of the China national standard GB/T 9846-2015(≥0.7 MPa),and can be a good choice as a wood adhesive for industrial application.

Fine-tuning hydroxylamines as single-nitrogen sources for Pd(0)-catalyzed diamination of o-bromo(or chloro)-biaryls

Transition metal-catalyzed diamination by hydroxylamines is a common approach for making three-membered aziridines,while its use for building the larger N-heterocycles is still underdeveloped.Herein,we report an efficient Pd(0)-catalyzed intermolecular[4+1]annulation of o-bromo(or chloro)-biaryls with bifunctional secondary hydroxylamines for the one-step assembly of synthetically useful carbazoles.Noteworthily,a linchpin for this domino reaction was the judicious selection of both the amino-sources and Pd(0)-catalysts for enabling the prerequisite oxidative addition of aryl halides to Pd(0)-species in the presence of hydroxylamines with a labile N-O bond.

Value of combining the serum D-lactate, diamine oxidase, and endotoxin levels to predict gut-derived infections in cancer patients

Objective:This is a retrospective observational cohort study.The objective of this retrospective observational cohort study was to evaluate the value of the combined serum D-lactic acid,diamine oxidase(DAO),and endotoxin levels to predict intestinal barrier impairment and gut-derived infection(GDI)in cancer patients.Methods:Cancer patients receiving chemotherapy or palliative care treatment at our hospital were enrolled in the study.The serum concentrations of DAO,D-lactic acid,and endotoxin were determined using the intestinal barrier function biochemical index analysis system.The patients'infection information came from the hospital's Medicom Prescription Automatic Screening System and themedical records.Three hundred fifty-three cancer patients were included in the study(53.8%female,73.7%cancer stage IV,27.8%had bowel obstruction).Results:The total incidence of GDI was 33.4%(118/353).The median length of hospital stay was 16 days for patients with GDI,compared with 7 days for patients without GDI(P<0.001).The media hospitalization costs were¥27,362.35 for patients with GDI compared with¥11,614.08 for patients without GDI(P<0.001).The serum concentrations of DAO,D-lactic acid,and endotoxin were significantly higher in patients with GDI.As malignant bowel obstruction(MBO)worsened,the concentrations of DAO,D-lactic acid,and endotoxin increased.Multivariate logistic regression models revealed that the DAO,endotoxin,IL-6,and C-reactive protein levels were significantly associated with an increased risk of GDI.In addition,we also found a fivefold increased risk of infection in patients withMBO compared with those without bowel obstruction(OR=6.210,P<0.001).All of the areas under the receiver operating characteristic curve(AUCs)for DAO,D-lactate,and endotoxin to predict GDI were<0.7(AUC=0.648,P<0.001;AUC=0.624,P<0.01;AUC=0.620,P<0.01,respectively).However,when the parameters were combined(DAO+D-lactate+endotoxin),the predictive power increased significantly(AUC=0.797,P<0.001).Moreover,combining these intestinal barrier indicators and the presence of MBO had better power to predict GDI than either alone(AUC=0.837,P<0.001).Conclusions:Combining the serum DAO,D-lactic acid,and endotoxin levels was a better predictor of GDI than any of the indicators alone,and combining these with the diagnosis of MBO could further improve the efficacy for predicting GDI.

血清二胺氧化酶测定的临床应用进展

二胺氧化酶（diamine oxidase;DAO,E.C.1.4.3.6）是存在于哺乳动物小肠的黏膜或纤毛上皮细胞中催化二胺的细胞内酶,它可通过调节细胞内的离子平衡、影响传导通路、促进细胞修复,对肠黏膜具有保护作用[1]。小肠黏膜屏障功能衰竭时或肠黏膜细胞坏死时血清DOA升高,因此,血液中的DOA活性可反映肠道损伤状态[2,3]。

耐盐性高吸水树脂的辐照合成及其后处理工艺

本实验提供了一种新的PVA/PAAS/EDTA高吸水性树脂及其制备方法。采用聚乙烯醇(Poly vinyl alcohol,PVA)、聚丙烯酸钠(Poly acrylate sodium,PAAS)和乙二胺四乙酸(Ethylene diamine tetraacetic acid,EDTA),将由这些材料组成的水溶液经电子束辐射交联合成共聚物凝胶,经浸洗液溶胀和洗涤,萃冻和冷冻干燥后处理,制备出耐盐性高吸水性树脂。采用正交设计原理选出最佳配比,用不同配比的洗涤液进行后处理,研究洗涤液对树脂吸液性能的影响。测试树脂的各项性能,与国内外著名产品进行比较。结果表明,本实验制备出的高吸水性树脂具有优良的吸液速率和离心保液量,去离子水吸液倍率((821.05±1.61)g·g-1)和生理盐水吸液倍率((72.57±3.01)g·g-1)则非常显著地优于国内外著名高吸水性树脂产品(P±0.01)。

Changes of plasma D(-) -lactate, diamine oxidase and endotoxin in patients with liver cirrhosis

BACKGROUND: Plasma D(-)-lactate and diamine oxidase (DAO) can reflect patients' intestinal mucosal condition. We evaluated the changes of plasma D (-)-lactate, DAO and endotoxin activities and their significance in patients with liver cirrhosis. METHODS: Fifty liver cirrhosis patients were enrolled into experimental group and 30 healthy people into control group. The plasma levels of D(-)-lactate, DAO and endo- toxin were detected spectrophotographically. RESULTS: The level of D(-)-lactate was significantly high- er in the experimental group than that in the control group (P<0.01). Significant differences of D (-)-lactate levels were observed in Child-Pugh subgroups of the experimen- tal group (P <0. 01). The level of DAO was significantly higher in the experimental group than that in the control group (P <0.01), but the level of DAO in Child-Pugh sub- group C was significantly lower than that in Child-Pugh subgroup B (P<0.01). The level of endotoxin was signifi- cantly increased in the experimental group except Child Pugh subgroup A (P<0.01). The plasma levels of D(-) lactate, DAO and endotoxin were positively correlated with each other (P<0.01). CONCLUSIONS: The data suggest that both plasma D(-) lactate and DAO activity are sensitive markers for early diagnosis of gut failure and endotoxemia in patients with liver cirrhosis. The impairment of intestinal barrier func- tion may be one of the critical reasons for deterioration of liver cirrhosis.

The production of biobased diamines from renewable carbon sources: Current advances and perspectives

Bio-based diamines are considered to be a promising alternative to traditional fossil-fuel-based diamines,the important platform chemical for the synthesis of polymer materials.In this review,the current status of the art of the synthesis of aliphatic and aromatic diamines from renewable biomass are considered.In the case of aliphatic diamines,we describe strategies for biologically producing diamines with different carbon numbers including 1,3-diaminopropane,1,4-butanediamine,1,5-pentanediamine,1,6-diaminohexane,1,8-diaminooctane,1,10-diaminodecane,and 1,12-diaminododecane.In addition,aromatic diamines produced from various kinds of renewable biomass,including lignin,cashew nut shell,and terpenoids,are reviewed here.Furthermore,the application of typical diamines in synthesis of polyurethane and polyamide are also reviewed.

Controversies about the use of serological markers indiagnosis of in flammatory bowel disease

The serological markers are increasingly used in diagnosis of inflammatory bowel disease(IBD).D-lactate and diamine oxidase are new indicators that can be used to reveal the damage to intestinal mucosa and permeability alteration in IBD.Although the two biological markers seem more sensitive,recent clinical trials and animal experiments have shown controversies about the use of them in diagnosis of IBD.Therefore, these markers should be interpreted cautiously and further prospective studies are needed to establish their clinical role in diagnosis of IBD.

Possible relationship between intestinal barrier function and formation of pigment gallstones in hamsters

BACKGROUND: The presence of bacteria in bile is an important factor in the formation of pigment gallstones. The bile of healthy people is sterile and bacteria in the biliary system come from endogenous infection from the gut. Yet, the route of bacterial translocation into the bile duct is still unclear. Theoretically, two routes exist: one is through the intestinal barrier and the other is by direct reflux from the sphincter of Oddi. This study was undertaken to explore the relationship between the effectiveness of intestinal barrier and the formation of pigment gallstones in hamsters. METHODS: Thirty-two hamsters were divided into an experimental and a control group, with 16 hamsters in each group. A low protein and high cellulose diet was given for 6 weeks to induce the formation of pigment gallstones in the experimental group (PS) and a normal diet was given to the control group (CON). Morphological changes, changes in the levels of serum endotoxin and diamine oxidase, and changes in the numbers of B lymphocytes, plasma cells and secretory immunoglobin A (sIgA) in the intestinal mucosa were assessed after 6 weeks. RESULTS: Four hamsters died during lithogenesis and body weight decreased in the PS group. Pigment gallstones were found in 11 hamsters at the end of the experiment, giving a lithogenesis rate of 91.67%. The serum endotoxin level before and after gallstone formation in the PS group was 0.2960 +/- 0.1734 U/ml and 8.2964 +/- 4.6268 U/ml, respectively (P<0.05). The blood diamine oxidase level before and after gallstone formation in the PS group was 2.6333 +/- 0.8037 U/ml and 3.3642 +/- 0.9545 U/ml, respectively (P<0.05). The numbers of B lymphocytes, plasma cells and sIgA in the intestinal mucosa in the PS group were 71.56 +/- 2.89, 68.65 +/- 2.09 and 27.56 +/- 1.07, respectively, and were significantly decreased compared with the corresponding values in the CON group (94.25 +/- 3.69, 93.47 +/- 3.98 and 42.57 +/- 1.96, respectively, P<0.05). CONCLUSIONS: A low protein and high cellulose diet can markedly reduce intestinal barrier function and facilitate the formation of pigment gallstones. The decrease of intestinal barrier function may take part in the formation of pigment gallstones.

SYNTHESIS AND PROPERTIES OF NOVEL POLY(IMINO KETONE)S AS HIGH-PERFORMANCE POLYMERS

Di(4-bromophenyl)ketone and various aromatic diamines as the monomers,a series of novel poly(imino ketone)s (PIKs)have been synthesized via palladium-catalyzed aryl amination,which is Hartwig-Buchwald polycondensation reaction.The structures of PIKs are characterized by means of elemental analysis,FT-IR,~1H-NMR and UV-Vis spectroscopy. The results show a good agreement with the proposed structure.The general properties of PIKs are studied by DSC,TG and wide-angle X-ray diffraction,the solubility behavior is...

HEAT-RESISTANT,PYRIDINE-BASED POLYAMIDES CONTAINING ETHER AND ESTER UNITS WITH IMPROVED SOLUBILITY

A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.

Synthesis of a new pyridine-containing diamine and related polyimide

A new kind of aromatic diamine monomer containing pyridine unit,2,6-bis[4-(4-aminophenoxy)phenoxy]pyridine(BAPP),was synthesized in three steps,using hydroquinone as starting material.A novel pyridine-containing polyimide was prepared from the resulting diamine BAPP with 4,4 -oxydiphthalic anhydride(ODPA) via a conventional two-step thermal imidization method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.

Synthesis of Novel Poly(aryl ether amide)s Containing the Phthalazinone Moiety

Two novel heterocyclic diamine monomers: 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-aminophenoxy)phenyl] (2H)phthalazin-1-one and 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-aminophenoxy)-3,5-dimethylphenyl](2H)phthalazin-1-one were successfully synthesized from readily available heterocyclic bisphenol-like monomers in two steps in high yield. A series of novel poly(aryl ether amide)s containing the phthalazinone moiety were successfully prepared by the direct polymerization of the novel diamines and aromatic dicarboxylic acids using triphenyl phosphite and pyridine as condensing agents.

Soluble Fiber Improves Management of Diarrhea in Elderly Patients Receiving Enteral Nutrition

Dietary fiber is a non-digestible carbohydrate providing beneficial effects for bowel health. The aim of this study was to evaluate the clinical effects of fiber supplementation in enteral feeding on elderly patients suffering from diarrhea. This study was conducted in 15 patients (7 men and 8 women, 79.0 ± 7.5 years) who had loose stools or diarrhea during enteral nutrition. The enteral formula was supplemented with soluble dietary fiber (5.2 g/day) for 3 weeks, which was then discontinued for 1 week to confirm its effects. The effects of soluble dietary fiber on stool frequency, the Bristol Stool Form Scale (which is designed to measure stool consistency), plasma diamine oxidase (DAO) activity, and concentrations of plasma short-chain fatty acids (SCFA) were evaluated. After supplementation with soluble dietary fiber, there were no significant differences in stool frequency but there was a significant improvement in stool consistency (P < 0.05). Furthermore, ingestion of soluble dietary fiber resulted in increased plasma DAO activity and significantly increased levels of plasma SCFA (P < 0.05). Supplementation with soluble dietary fiber may be beneficial for improving stool consistency in patients suffering from diarrhea during enteral nutrition. A further controlled trial is warranted to examine the preventive effects of soluble dietary fiber in patients suffering from diarrhea.

Green and selective hydrogenation of aromatic diamines over the nanosheet Ru/g-C_(3)N_(4)-H_(2) catalyst prepared by ultrasonic assisted impregnation-deposition method

In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_(2) were synthesized via ultrasonic assisted impregnation-deposition method.Ultrafine Ru nanoparticles(<2 nm)were highly dispersed on nanosheet g-C_(3)N_(4)-H_(2).Strong interaction due to Ru-Nx coordination facilitated the uniform distribution of Ru species.Meanwhile,the involvement of surface basicity derived from abundant nitrogen sites was favourable for enhancing the selective hydrogenation performance of bi-benzene ring,i.e.,almost complete 4,40-diaminodiphenylmethane(MDA)conversion and>99%4,40-diaminodicyclohexylmethane selectivity,corresponding to a reaction activity of 35.7 mol_(MDA) mol_(Ru)^(-1) h^(-1).Moreover,the reaction activity of catalyst in the fifth run was 36.5 mol_(MDA) mol_(Ru)^(-1) h^(-1),which was comparable with that of the fresh one.The computational results showed that g-C_(3)N_(4) as support was favorable for adsorption and dissociation of H_(2) molecules.Moreover,the substrate scope can be successfully expanded to a variety of other aromatic diamines.Therefore,this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines.

Synthesis of 2-methylpyrazine from cyclocondensation of ethylene diamine and propylene glycol over promoted copper catalyst

The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.

Ultrasonicwave-assisted tandem-reaction for synthesis of symmetrical vicinal diamines

A practical synthesis of symmetrical vicinal diamines with broad chemistry scope is described. The key step is the ultrasonicwave promoted tandem-reaction, two-step reaction sequence combining Mannich double condensations with benzo- triazole, glyoxal and primary or secondary amines and reduction of the bis（benzotriazole）-adducts with sodium borohydride proceeded smoothly in tetrahydrofuran in high yield at room temperature.

The Effect of Glycyl-Glutamine Dipeptide Concentration on Enzyme Activity, Cell Proliferation and Apoptosis of Jejunal Tissues from Weaned Piglets

An experiment was conducted in a singly factorial design to study the effect of glycyl-glutamine dipeptide on enzyme activity, cell proliferation and apoptosis of jejunal tissues from weaned piglets at different glycyl-glutamine concentration levels of 2, 4, 10, 20, and 30 mmol L-1, respectively. The glutaminase activity, diamine oxidase （DAO） activity, cell peoliferation, apoptosis, and perotein metabolism were measured by the tissue culture method in vitro using jejunal tissues. The immunohistochemical method was used to study the cell proliferation and apoptosis of jejunal tissues. The results showed that compared to the blank control, the percentage and MOD value of BrdU-positicve cells incubated with glycyl-glutamine dipeptide solution were significantly （P0.05） increased. Accordingly, the percentage and MOD value of caspase-3-positive cells from tissue incubated with glycyl-glutamine dipeptide were notably lower （P0.05） than that from the control treatment. The glycyl-glutamine dipeptide increased the glutaminase activity, DAO activity and protein content of jejunal tissues, as the dipeptide concentration was on the rise （P0.05）. These results indicated that glycyl-glutamine dipeptide affected the jejunum development and adaptation of weaned piglets, and the function might be fulfilled by enhancing the glutamine-related enzyme activity, thereby increasing the consumption of glutamine, and then improving the jejunal cell proliferation and suppressing cell apoptosis. The effects of glycyl-glutamine dipeptide relied in a dose-dependent manner, and the maximum effect was achieved at 20-30 mmol L-1 glycyl-glutamine dipeptide.

No-Aldehydes Glucose/Sucrose-Triacetin-Diamine Wood Adhesives for Particleboard

A three reagents adhesive system for wood particleboards not containing any aldehyde was developed by the reaction of glucose or sucrose with triacetin(glycerin triacetate)and with hexamethylene diamine.The system was found to be based on the mix of three reactions,namely the reaction of(i)glucose with triacetin,(ii)of the diamine with triacetin,and(iii)of glucose with the diamine.The chemical species formed were identified by Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-ToF)mass spectrometry.Wood particleboard panels were prepared with this adhesive system and gave good internal bond(IB)strength results suitable for interior grade panels and with extremely low formaldehyde emission.

Effect of hypertransfusion on the gastrointestinal tract after cardiac arrest in a porcine model

BACKGROUND:This study aimed to determine the potential protective effect of inducing hypertransfusion to the gastrointestinal tract following a porcine model of cardiac arrest and cardiopulmonary resuscitation(CPR) by evaluating the influence of gastrointestinal ultrastructure,ATPase and serum diamine oxidase.METHODS:Ventricular fibrillation was induced by programmed electrical stimulation in 16 male domestic pigs(n=8/group).Four minutes after ventricular fibrillation,CPR was performed.The pigs that successfully restored spontaneous circulation received intravenous infusion of either norepinephrine to maintain the mean arterial pressure at 130%of the baseline before ventricular fibrillation or normal saline.Serum diamine oxidase and gastrointestinal ATPase activity were determined,and histopathological examination of the gastrointestinal tract was performed by light and electron microscopy.RESULTS:CPR caused significant injury to the gastrointestinal tract,elevating serum diamine oxidase and causing destruction of intestinal microvillus in control animals.Na^+-K^+ ATPase and Ca^(2+)ATPase activity in gastric tissue were significantly elevated in animals receiving hypertransfusion treatment compared with the control animals.Hypertransfusion also significantly reduced serum diamine oxidase to below control levels after CPR.Moreover,severe injury sustained by the gastrointestinal tissue was markedly ameliorated under hypertransfusion conditions compared with the control animals.CONCLUSIONS:Gastrointestinal injury and abnormal energy metabolism were strikingly evident following CPR.Hypertransfusion inducing hypertension can improve energy metabolism and ameliorate gastrointestinal mucosal injury,indicating that hypothermia significantly ameliorates gastrointestinal injury sustained following cardiac arrest.