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Context Dietary supplementation with phytobiotics may form part of an alternative strategy to the use of antibiotics as growth promoters in the poultry industry. Essential oils of rosemary (Rosmarinus officinalis L.) may have antimicrobial and antioxidant properties. Aims The aims were to evaluate in vitro characteristics of non-encapsulated and encapsulated rosemary essential oils, and to investigate their effects on growth performance, intestinal morphology and microbial population in broiler chickens. Methods Essential oil main components were determined, and the minimum inhibitory concentration and 2,2-diphenyl-1-picrylhydrazyl radical assay methods were applied for determination of antimicrobial and antioxidant activities, respectively. In an in vivo study of performance, 1-day-old male chicks (n = 420) were randomly assigned to seven dietary treatments with five replicates of 12 birds in a completely randomised experimental design. Treatments were control (basal) diet, and basal diet supplemented with chitosan (encapsulating agent) at 150 mg/kg, encapsulated and non-encapsulated rosemary essential oils at both 150 and 300 mg/kg, and the antibiotic flavophospholipol at 650 mg/kg. Key results Non-encapsulated essential oil had stronger antioxidant activity than the encapsulated form (IC50 values 0.969 and 1.879 mg/mL, respectively). Non-encapsulated essential oil had greater antimicrobial effect against Escherichia coli, whereas the encapsulated form was more effective against Staphylococcus aureus. During the whole growing period of the in vivo study, supplementation with different levels of non-encapsulated or encapsulated essential oils significantly (P

Background and aims: Using iron as a food additive usually causes undesirable sensory changes and side effects in humans. In this study, we made iron (Fe) nanoparticles (NPs) and studied the cytotoxicity of FeSO4 bulk and NPs on HT-29 cells and different doses of these particles on rat intestine. Methods: Particle size of nanoscale was achieved by mechanical technique. Iron particles were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of iron particles with different concentrations (6.25, 3.125, and 1.57 mM/mL) on the colon cell line was performed using the MTT assay at 24, 48, and 72 hours. Apoptosis and necrosis of the cells were assessed using Annexin V-FITC staining and propidium iodide (PI) at 24 h. In an in vivo study, Taftoon bread was produced from fortified wheat flour with FeSO4 bulk and NPs, which are recommended in human diet (9, 18, and 27 mg of elemental iron/kg flour). Wistar rats were fed daily with fortified bread for 21 days and their colon and small intestine were then evaluated histopathologically. Statistical analyses were performed using SPSS 22.0 software by chi-square test. Results: The synthesized FeSO4 NPs were smaller than 100 nm, and they had more adverse effects on the viability of the HT-29 cells compared to the bulk- FeSO4 at 72 hours. Flow cytometric study showed that the early apoptosis of cells by the bulk form was more than the NPs, but at the low concentration (1.57 mM/mL), the NPs induced more necrosis than the bulk particles (P=0.063). The survival rate of cells facing all concentrations of NPs and bulk- FeSO4 decreased dose dependently (P=0.075). In vivo results revealed that there were no pathological changes in rats’ intestinal tissues. Conclusion: The bulk and NPs of iron have adverse effects on the HT-29 cells, but no histopathological changes were seen on rats’ intestinal cells.

Summary: The effects of nanoencapsulated cumin essential oil (EO) feeding broilers on growth performance, mucin 2 gene expression, blood parameters, and immune responses to phytohemagglutinin (PHA) and 2, 4-dinitrochlorobenzene (DNCB) were evaluated. In a completely randomized design, 1050 male day-old Ross 308 broilers were distributed into 7 dietary treatments with 5 replicates of 30 birds per replication. Dietary treatments included 1) control basal (no additives), 2) control antibiotic growth promoter (flavophospholipol at 650 mg/kg), control basal plus a solution of 3) 150 mg/kg of chitosan nanoparticles, free-form cumin EO at 4) 100 or 5) 200 mg/kg, and nanoencapsulated cumin EO at 6) 100 and 7) 200 mg/kg. The use of 200 mg/kg nanoencapsulated cumin EO significantly (P < 0.01) increased body weight gain and mucin 2 gene expression and improved feed conversion ratio compared with other treatment. The highest feed intake was significantly (P < 0.01) in the control treatment during day 15 to 18 and day 29 to 42. In birds fed with nanoencapsulated cumin EO, serum total triglyceride and low-density lipoprotein cholesterol levels were also significantly lower than birds in the control group. Sheep red blood cell antibody titer (35 and 42 d), immunoglobulin G (42 d), heterophilus (H), lymphocyte (L), and H/L ratio, PHA, and DNCB (42 d) were affected by the nanoencapsulation process of cumin EO (P

Ferrous sulfate nanoparticles (FSNPs) were synthesized and characterized to mitigate the undesirable effects of ferrous sulfate bulk particles (FSBPs) as a supplement or fortificant in health/food industries.The toxicity of FSNPs and FSBPs was evaluated against AGS, PLC/PRF/5, and HGF1-PI 1 cell lines. Then, Wistar rats were fed three levels of FSNPs and FSBPs fortified-bread. Growth performance, hematological parameters, and histopathological changes in treated rats were assessed after 21 days.High concentrations of FSNPs (3.125 and 6.25 mM) increased the necrosis of AGS cells. A low level of FSNPs (1.57 mM) did not affect the viability of cells after 72 h. Fibroblasts did not show apoptosis and necrosis after exposing 1.57 mM of FSNPs. In rats, 9 mg elemental iron of FSNPs/day enhanced hemoglobin, PCV, and ferritin values and increased the body weight gain (p 0.05). FSNPs fortified-bread induced no clinical symptom or histopathological lesion in rats.FSNPs affect cells in a dose-dependent manner. The results indicate that FSNPs at the low level do not have adverse effects on normal fibroblasts and rats. Significant weight gain in rats having a low level of FSNPs compared to the FSBPs indicates the negligible toxicity of FSNPs at low concentrations.

This study was carried out to investigate the interaction between humic material complex (HMC) and probiotics mixture containing Bacillus subtilis (4 × 109 CFU/ gr) and Bacillus coagulans (2 × 1011 CFU/ gr) (PSC) on growth performance, morphology and microbial population of intestine in male broiler chicks. Treatments included: (1) basal diet (control diet), (2) basal diet plus 0.02% probiotics mixture (PSC), (3) basal diet with half mineral supplement plus 0.125% HMC (HMC1), (4) basal diet with half mineral supplement plus 0.125% HMC plus 0.02% PSC (HP1), (5) basal diet without inorganic supplement plus 0.25% HMC (HMC2) and (6) basal diet without inorganic supplement plus 0.25% HMC plus 0.02% PSC (HP2). Over the whole experimental period the HP1 performance was similar to the control group. The villus length and width in the chicks fed with HP1 and the villus length ratio to crypt depth in the treatment containing HMC1 were higher than that in other treatments (P

This survey aimed to evaluate the effects of dietary supplementation of different forms of savory essential oil (SEO) on growth performance, intestinal morphology and microbial population in broiler chickens. A total of 360 one-day-old male broilers were randomly allocated to 6 dietary treatment groups with 5 replicates per treatment and 12 birds per pen. The experiment consisted of a 2×3 factorial arrangement including two different forms [encapsulated SEO (ESEO) and nonencapsulated SEO (NSEO)] in three levels (0, 150, and 300 mg/kg diet) of SEO. Growth performance, jejunal morphology and intestine microbial population were examined. Our results revealed that feed intake was not influenced by the dietary treatments in different experimental periods. As well as, the experimental diets did not influence body weight gain (BWG) and feed conversion ratio (FCR) during the starter period. However, at the grower, finisher, and also whole rearing periods, broilers which received 150 mg/kg SEO had significantly higher BWG and lower FCR compared to the birds fed the control diet. The final body weight (FBW) was also higher in chickens fed with diet supplemented with 150 mg/kg SEO in comparison to the others. The results also revealed that 150 mg/kg SEO, significantly increased the concentration of Lactobacillus and decreased the intensity of coliforms in the ileal digesta in comparison to the control diet. Furthermore, villus height was significantly lower in birds fed the control diet than in the birds that consumed different levels of SEO. Eventually, the findings of this experiment revealed that dietary supplementation of SEO, especially at 150 mg/kg level, was effective in raising the populations of beneficial microorganisms in the gastrointestinal tract as well as improving intestinal morphology and growth performance of broilers.

The addition of essential oil (EO) as chitosan encapsulated can increase the efficiency of these oils in broiler feeding. Therefore, the objective of the current research was to explore the antibacterial and antioxidant potential of garlic essential oil (GEO) (free vs. nanoencapsulated) and their effects on performance, gene expression of mucin2, microbial, and morphology of intestine in broilers. A total of 900 1-day-old male broilers (Ross 308) were assigned to six dietary treatments (0, 100, and 200 mg/kg free GEO and 0 (contain of chitosan), 100 and 200 mg/kg nanoencapsulated GEO) with a 2 × 3 factorial arrangement based on completely randomized design. Garlic essential oil encapsulation with chitosan significantly enhanced antibacterial and antioxidant parameters. At 100 mg/kg nanoencapsulated GEO had significant (P

Deferasirox pyridine solvate [(DFX)(py)] and its Cu(II) complex [Cu(DFX)(py)], (DFX= deferasirox, py=pyridine) were synthesized and characterized using several techniques such as elemental analysis, Fourier-transform infrared (FTIR), molar conductivity and vibrating sample magnetometer (VSM). In addition, the structure of both compounds was determined using single-crystal X-ray diffraction method. In the case of the Cu(II) complex, it was found that the Cu(II) central ion was surrounded by the ONO donor atoms of deferasirox and the nitrogen atom of pyridine. Antimicrobial activities of the synthesized compounds were investigated against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa bacteria. Likewise, the antibiofilm activity of these compounds was investigated against S. aureus and P. aeruginosa bacteria. It was observed that the [Cu(DFX)(py)] complex presented higher antimicrobial and antibiofilm activities compared with the other compounds. The antimicrobial property of these compounds was also evaluated using molecular docking with GlcN-6-P synthase. Furthermore, the antioxidant activity of the compounds was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging method. The [Cu(DFX)(py)] complex demonstrated a strong antioxidant activity with the IC50 of 1.1 mM.

The aim of this in vitro study was to assess hydro-distillated Mentha pulegium essential oil (MPE) by composition, antioxidant capacity, and antibacterial properties and compared these indexes with synthetic antibiotics and antioxidants. The essential oil active ingredients determined by GC mass procedure while antioxidant activity determined by DPPH technique. Furthermore, by applying four bacterial strains (Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, and Bacillus cereus), antibacterial properties of pennyroyal was distinguished by disk diffusion, MIC, and MBC methods in different concentrations. The results showed that pennyroyal essential oil has 29 constituents so that cis-pulegone oxide, (E)-p-mentha-2-en-1-ol, and 3,3′-dimenthol being the main components. In addition, strong antimicrobial activity against all four microorganisms tested, especially on Gram positive bacteria, was distinguished, even though it was more effective in higher doses. Besides, the essence was able to reduce the stable free radical DPPH with an IC50 of 1.027 mg/mL while BHT was 20.280 μg/mL. In conclusion, pennyroyal essential oil can be a good substitution for some synthetic antibiotics and antioxidants.

The current experiment was conducted to evaluate the effects of Se-chitosan as organic Se, Na selenite, vitamin E, and their various combinations on growth performance, carcass traits, meat quality, and blood indices of broiler chickens. A total of 480 one-d-old broiler chickens were randomly assigned to the Se source (inorganic and organic), Se inclusion (0.15 and 0.30 mg/kg), and vitamin E (0 and 80 IU/kg) in a 2 × 2 × 2 factorial arrangement of treatments with 5 pens per treatment and 12 broiler chickens per pen. Broiler chickens fed 0.30 mg Se/kg had a greater body weight gain and a lower feed conversion ratio at 11 to 24 d (P

A diketone-based tridentate Schiff base, 3-[(2-hydroxyphenyl)amino]-1,3-diphenylprop-2-en-1-one (H2L), and its oxo-vanadium(V) dimer complex, [VO(L)(OMe)]2, were synthesized and characterized using spectroscopic and physicochemical techniques. Single crystal X-ray diffraction indicated that the Schiff base ligand in its deprotonated form was found to bind to the V(V) ion through the azomethine nitrogen, amine and phenolic oxygens in a distorted octahedral geometry. The other positions around the V(V) center were occupied by an oxido group and two oxygens from methoxido ligands. Antimicrobial studies showed that the synthesized complex indicated significant antimicrobial activities against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 33591 and 29213) bacteria while no antibacterial activity was observed for the ligand alone. The potential of [VO(L)(OMe)]2 as an antimicrobial agent, was additionally investigated using molecular docking of the complex with GlcN-6-P synthase.

A total of 288-day-old male broilers were allocated to six dietary treatments to evaluate the effects of zinc source and Bacillus coagulans supplements and their interaction on growth, intestinal microbial population, carcass traits and meat quality in broiler chickens. Three levels of dietary supplemental Zn source (100 mg/kg of DM diet zinc oxide, 25 and 50 mg/kg of diet zinc oxide nanoparticles (Zn-nan)) and two levels of B. coagulans (0 and 100 mg/kg of diet) were combined as a completely randomised design with a 3 × 2 factorial arrangement. B. coagulans increased the body weight gain, body weight and feed conversion ratio. The lactic acid producing bactereia of ileal were increased by B. coagulans supplementation, and its coliform count was decreased by Zn-nan in a dose-dependent manner. The B. coagulans increased the relative weights of legs and proventriculus and reduced weights of livers, abdominal fat and meat thiobarbituric acid (TBA) value. Likewise, dietary B. coagulans increased pH, yellowness and lightness values of leg muscles. Birds fed Zn-nan50 had lower liver weight, TBA and cooking loss and higher yellowness values than chicks fed ZnO-100. In conclusion, the dietary supplementation with B. coagulans improved broiler performance, microbial population and meat quality. The Zn-nan in lower dose could be a good substitution in mineral premix instead of zinc oxide. In addition, the Zn-nan improved intestinal microbial population, carcass characteristics and oxidative stability of chicken meat; however, the combination of two levels of Zn-nan with B. coagulans did not vary the measured parameters.

A tridentate Schiff base ligand (E)-N′-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide (H2L) and its oxido-vanadium(V) complexes with formulae [VO(L)(MeOH)(OMe)] (1), [VO(L)(OEt)] (2), and [VO(L)(OPr)] (3) have been synthesized and fully characterized by physicochemical and spectroscopic methods including elemental analysis, FT-IR, 1H NMR and molar conductivity. The solid state structures of H2L and complexes 1–3 have also been investigated using single crystal X-ray analysis. It was concluded that H2L crystallized in keto form in the solid state; however in all complexes, the ligand appears in the enol form. The coordination geometry of complex 1 was found to be distorted octahedral while complexes 2 and 3 adopt square pyramidal geometries. The antimicrobial activity of these compounds was also evaluated against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 33591 and 29213) bacteria and the results showed that all three complexes have significant antibacterial activities. In order to determine the potential of these complexes as antimicrobial agents, molecular docking of the complexes with GlcN-6-P synthase was also investigated.

The effects of essential oil (EO) of oregano and chitosan on the microbial quality and growth inhibition of Listeria monocytogenes and Escherichia coli O157:H7 in the Iranian traditional ready-to-barbecue chicken was evaluated. Thus, three groups of samples were prepared. One of them was considered to evaluate for aerobic plate count (APC), lactic acid bacteria (LAB), psychrophilic and enterobacteriacae counts and the other two groups were inoculated with E. coli O157:H7 and L. monocytogenes 4b to investigate the effect of oregano EO and chitosan on pathogenic bacteria. All groups were stored at 3, 8 and 20°C. Oregano showed antibacterial effects against APC, LAB, psychrophilics, enterobacteriacae and E. coli O157:H7, whereas, such an effect was not observed against L. monocytogenes. Chitosan individually did not show an inhibitory effect on the spoilage-inducing bacteria and E. coli, but was effective against L. monocytogenes. Using chitosan and oregano EO in combination can reduce the number of spoilage and safety indicators and also the two food-borne pathogens in ready-to-barbecue chicken meat.

The microbiological and biochemical changes occurred during the fermentation of camel milk inoculated by three selected bacterial starter, were investigated as well as the sensory evaluation of the product. Milk samples were collected from camel herds of southeastern of Iran. Chr. Hansen ABT-10 starter including Lactobacillus acidophillus, Biphidobacterum biphidum and Sterptococcus thermophilus in ratio of 0.50 g per 100 mL of camel milk was added. This fermented product was examined at the 0, 3rd, 6th and 9th days for microbiological, biochemical and sensory evaluations. The results showed the number of starter bacteria was maintained at least 106 CFU mL-1 during nine test days. It was shown that it could be used as fermented-probiotic drink. The product did not show any microbial contamination. The acidity and protein amount of produced drink showed a significant (p < 0.05) increase in different test days. Fat, solids-not-fat and ash amount of the product showed significant differences at the ninths’ test day compared to the zero test day (p < 0.05). Organoleptic properties of product including flavor, color, odor, consistency, mouth feel and overall acceptance were significantly improved (p < 0.05). Therefore, the produced fermented–probiotic drink, in addition to keep maintenance and increased nutritional quantity value, was accepted by consumers in terms of organoleptic properties and it could be used as a healthy and functional drink.

Twenty seven years after the discovery of high-temperature superconductivity \cite{BedMu}, consensus on its theoretical explanation is still absent. To a good extent, this is due to the difficulty of studying strongly correlated systems near half-filling, needed to understand the behaviour of one or few holes doped into a CuO$_2$ layer. To simplify this task it is customary to replace three-band models \cite{Emery} describing the doping holes as entering the O $2p$ orbitals of these charge-transfer insulators \cite{ZSA} with much simpler one-band Hubbard or $tJ$ models \cite{rev1,rev2}. Here we challenge this approach, showing that not only is the dynamics of a doped hole easier to understand in models that explicitly include the O orbitals, but also that our solution contradicts the long-held belief that the quantum spin fluctuations of the antiferromagnetic (AFM) background play a key role in determining this dynamics. Indeed, we show that the correct, experimentally observed dispersion is generically obtained for a hole moving on the O sublattice, and coupled to a N\'eel lattice of spins without spin fluctuations. This marks a significant conceptual change in our understanding of the relevant phenomenology and opens the way to studying few-holes dynamics without finite-size effect issues \cite{BayoB}, to understand the actual strength of the "magnetic glue"., Comment: Four figures

Modern challenges of food science require a new understanding of the determinants of food quality and safety. Application of advanced imaging modalities such as magnetic resonance imaging (MRI) has seen impressive successes and fast growth over the past decade. Since MRI does not have any harmful ionizing radiation, it can be considered as a magnificent tool for the quality control of food products. MRI allows the structure of foods to be imaged noninvasively and nondestructively. Magnetic resonance images can present information about several processes and material properties in foods. This review will provide an overview of the most prominent applications of MRI in food research.

Effects of different medium-voltage electrical stimulation (ES) and ageing on postmortem changes in longissimus dorsi muscle of the fat-tailed sheep were studied. Fifteen male animals were divided into 5 equal groups (n= 3) including: T₁ (control, without ES), T₂ (100 V/30 s), T₃ (100 V/60 s), T₄ (150 V/30 s), and T₅ (150 V/60 s) with fixed frequency of 50 Hz. Five minutes after sticking, the carcasses were stimulated in order of the treatments. After normal processing, they were kept at 6 °C for 14 d. ES accelerated the glycolytic rate resulting in a significant fast fall in pH (P0.05) during the 1st 6-h postmortem (PM) with a gradual decline until 24-h PM, and a simultaneous significant reduction in adenosine triphosphate (ATP) content (P0.05). There was a significant (P0.05) decline in the total calpain activity during the 1st 6-h PM. The muscles from ES carcasses had significantly (P0.05) lower water holding capacity (WHC) than those from nonstimulated ones. Ageing revealed a significant (P0.05) effect on the reduction of WHC. No significant difference was found for the mean value of the muscle color (L*, a*, and b*) in all treatment groups during ageing (P0.05). The results of free amino acid (FAA) content and myofibrillar fragmentation index (MFI) revealed a significant improvement of proteolysis and tenderness by ES and ageing (P0.05). In the present study, higher voltage/duration (150 V/60 s) showed greater effects and significantly accelerated glycolysis, pH decline, and ATP depletion and thus decreased the time for rigor completion and improved the tenderness.

The enzyme rhodanese (thiosulfate:cyanide sulfurtransferase) is an ubiquitous enzyme with activity in all living organisms, from bacteria to man. It has been suggested that this enzyme plays a central role in cyanide detoxification. The purpose of this investigation was to determine rhodanese activities in different tissues of human and compare them with those found in domestic animals. Normal human tissues were obtained from consenting patients who had undergone surgery after confirmation of nonneoplastic condition. Tissue extracts were prepared from liquid nitrogen-frozen samples and rhodanese specific activity and activity per gram tissue was measured by determination of enzymatically formed thiocyanate. The highest activity of rhodanese was found in kidney, followed by liver, brain, lung, muscle, and stomach. Other tissues studied did not show significant rhodanese activity. The results obtained in this study were compared with previously reported information on domestic animals. Human liver contains lower rhodanese activity compared with ruminants and nonruminants, except for dog which has comparable hepatic activity with human. Human kidney contains significant activity and the value is higher than those of camels, pigs, dogs, and chickens and is comparable with those of goats. The results of this study might indicate the involvement of rhodanese in cyanide detoxification in tissues which might be more exposed to cyanide due to higher blood supply to these tissues. On the other hand, rhodanese might perform other functions in human organs which are specific to these tissues.

International audience; Selenium compounds play a major role in Biology, where they are often associated with pronounced antioxidant activity or toxicity. Whilst most selenium compounds are not necessarily hazardous, their often selective cytotoxicity is interesting from a biochemical and pharmaceutical perspective. We have synthesized a series of amphiphilic molecules which combine a hydrophilic seleninic acid head group - which at the same time serves as thiol-specific warhead - with a hydrophobic tail. These molecules possess a surface activity similar to the one of SDS, yet their biological activity seems to exceed by far the one of a simple surfactant (e.g. SDS) or seleninic acid (e.g. phenyl seleninic acid). Such compounds effectively haemolyse Red Blood Cells and exhibit pronounced activity against Saccharomyces cerevisiae. From a chemical perspective, the seleninic warheads are likely to attack crucial cysteine proteins of the cellular thiolstat.

A hole in a two-dimensional Ising antiferromagnet was believed to be infinitely heavy due to the string of wrongly oriented spins it creates as it moves, which should trap it near its original location. Trugman showed that, in fact, the hole acquires a finite effective mass due to contributions from so-called {\it Trugman loop} processes, where the hole goes nearly twice around closed loops, first creating and then removing wrongly-oriented spins, and ending up at a different lattice site. This generates effective second- and third-nearest-neighbor hopping terms which keep the quasiparticle on the sublattice it was created on. Here, we investigate the trapping of the quasiparticle near a single attractive non-magnetic impurity placed at one lattice site. We consider the two cases with the quasiparticle and impurity being on the same versus on different sublattices. The main result is that even though the quasiparticle can not see the bare disorder in the latter case, the coupling to magnons generates an effective renormalized disorder on its own sublattice which is strong enough to lead to bound states, which however have a very different spectrum than when the quasiparticle and impurity are on the same sublattice., 11 pages, 9 figures

Despite the known antihistaminic effects of PSAO, this enzyme remains unrecognized as an antihistamine additive in the food industry. The objective of this study was to ascertain the plausible histamine-degrading effects of a new food-grade additive (pea seedling extract) in tuna fish. PSAO was purified from cultured pea seedlings via ionexchange and size-exclusion chromatography. SDS-PAGE results indicated that the PSAO subunit has an apparent molecular weight of about 95 kDa. To evaluate the optimized conditions for antihistaminic activity of the enzyme, the reaction of PSAO and histamine was carried out in KPi buffer under conditions relevant to the fish processing industry. 1 unit mL-1 of PSAO significantly reduced the histamine content at pH 7.0 but not at pH 5.0. Accordingly, its antihistaminic activity was assessed in homogenized skipjack tuna fish (Katsuwonus pelamis) using an ion-paired HPLC method. The results showed that PSAO can reduce 87.14% of the histamine content of the tuna fish at pH 7.0, 37°C. This study indicates that PSAO - purified or even filtrate of pea seedling homogenate - can degrade histamine, which suggests practical application of this enzyme in fish processing industry.

We study the charge dynamics of the quasiparticle that forms when a single hole is doped in a two-dimensional antiferromagnet as described by the one-band t-t'-t"-J model, using a variational approximation that includes spin fluctuations in the vicinity of the hole. We explain why the spin fluctuations and the longer range hopping have complementary contributions to the quasiparticle dynamics, and thus why both are essential to obtain a dispersion in agreement with that measured experimentally. This is very different from the three-band Emery model in the strongly-correlated limit, where the same variational approximation shows that spin fluctuations have a minor effect on the quasiparticle dynamics. This difference proves that these one-band and three-band models describe qualitatively different quasiparticles in the insulating limit, and therefore that they cannot both be suitable to describe the physics of very underdoped cuprates.

We study the bound states of a three-dimensional Holstein polaron near various kinds of single impurities, using the momentum average approximation. We show that the electron-phonon coupling is responsible for a strong renormalization of the impurity potential, resulting in an effective potential with significant retardation effects, which describes essential physics ignored by "instantaneous" approximations. The accuracy of our approximation is gauged by comparison with results from Diagrammatic Monte Carlo for the case of an impurity that modifies the on-site energy of the electron. We also discuss impurities that modify the local strength of the electron-phonon coupling, as well as isotope substitutions that change both the electron-phonon coupling and the phonon frequency, and contrast and highlight the difference between these cases., 13 pages, 11 figures; Accepted for publication in Phys Rev B

Using the momentum average (MA) approximation, we find an analytical expression for the disorder-averaged Green's function of a Holstein polaron in a three-dimensional simple cubic lattice with random on-site energies. The on-site disorder is assumed to be weak compared to the kinetic energy of the polaron, and is treated perturbationally. Within this scheme, the states at the bottom of the polaron band are found to have an infinite lifetime, signaling a failure of perturbation theory at these energies. The higher-energy polaron states have a finite lifetime. We study this lifetime and the disorder-induced energy shift of these eigenstates for various strengths of disorder and electron-phonon coupling. We compare our findings to the predictions of Fermi's golden rule and the average T-matrix method, and find a significant quantitative discrepancy at strong electron-phonon coupling, where the polaron lifetime is much shorter than Fermi's golden rule prediction. We attribute this to the renormalization of the on-site potential by the electron-phonon coupling., Comment: 10 pages, 7 figures

Spin accumulation is generated by injecting an unpolarized charge current into a channel of GaAs two-dimensional electron gas subject to an in-plane magnetic field, then measured in a nonlocal geometry. Unlike previous measurements that have used spin-polarized nanostructures, here the spin accumulation arises simply from the difference in bulk conductivities for spin-up and spin-down carriers. Comparison to a diffusive model that includes spin subband splitting in magnetic field suggests a significantly enhanced electron spin susceptibility in the two-dimensional electron gas.