111 mg/mL ( Van der Merwe et al., 2012; Wang, Deng, Li, & Wang, 2007). This problem can be minimized by using cyclodextrins

(CDs), that present special ability to complex with a variety of guest molecules, which enables their solubility, stability, bioavailability, protection against light-induced decomposition, to suppress unpleasant odors or tastes and achieve a controlled release of certain constituents ( Astray, Gonzalez-Barreiro, Mejuto, Rial-Otero, & Simal-Gándara, 2009), and still increase Galunisertib chemical structure the antioxidant activity of many compounds ( Lu, Cheng, Hub, Zhang, & Zou, 2009). Several studies have been conducted in search of natural antioxidants for food preservation in place of BHT (butylated hydroxytoluene), that may be responsible for liver damage and carcinogenesis (Krishnaiah, Sarbatly, & Nithyanandam, 2011). An alternative to this problem is the supplementation of foods and liquid drinks with natural antioxidants complexed with cyclodextrin (Basu & Del Vecchio, 2001). Thus, the MGN:β-CD complex may have future application in the food, pharmaceutical and cosmetic industries. The complexation of MGN in β-cyclodextrin (β-CD) has been described by our group, its stoichiometry determined as 1:1 and its apparent formation constant (KF) was calculated

using the Benesi–Hildebrand method and by cyclic voltammetry ( Ferreira et al., 2010). Other studies ( Huang, He, Lu, Ge, & Guo, 2011; Teng, Yu, Zhai, Li, & Liu, 2007; Zhang et al., 2010) also show that the inclusion of MGN on the CDs cavity AZD5363 in vitro increases its solubility and bioavailability. However, it is still unknown whether entrapment in the internal cavity of CDs affects the antioxidant activity of MGN. Thus, the aim of this study was to characterize the MGN:β-CD complex and to evaluate its antioxidant aminophylline activity, using radical scavenging activity toward 2,2′-diphenyl-1-picrylhydrazyl radical (RSA-DPPH ) and Oxygen Radical Antioxidant

Capacity (ORAC) assay using Fluorescein as a probe molecule. In addition, its protective effect against peroxyl radical-initiated membrane lipid peroxidation was evaluated. DPPH (2,2′-diphenyl-1-picrylhydrazyl radical), two types of β-cyclodextrin (β-CD) [CAS Number 7585-39-9 (for DSC studies) and CAS Number 68168-23-0], Fluorescein disodium salt (FL), Trolox, soy phosphatidylcholine and AAPH were purchased from Sigma–Aldrich (St. Louis, USA). Gallic acid (GA) was obtained from Vetec Química Fina Ltda. (Rio de Janeiro, Brazil) and the fluorescent fatty acid-analog, 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-S-indacene-3-undecanoic acid (C11-BODIPY581/591), from Molecular Probes (Ontario, Canada). MGN (Fig. 1) was obtained from an ethanolic extract prepared from dried bark of M. indica, recrystallized in aqueous ethyl acetate and characterized ( Barreto et al., 2008). All the reagents were of analytical grade.

The second phase of BE occurs at retrieval, where the extrapolation beyond the original scene borders that occurred in the first phase is revealed by a subsequent memory error. Specifically, if presented with exactly the same scene PD-0332991 order a second time, people frequently judge the scene on this occasion to have less background, making it appear to be closer-up than the first scene. The fact that the studied view need only be absent for

as little as 42 msec for BE to be apparent (Intraub and Dickinson, 2008) underscores the online and spontaneous nature of this effect. The first stage of BE, involving the active extrapolation of the scene beyond the boundaries, we hereafter refer to as the BE effect to differentiate it from the subsequent memory error, which we call the BE error. The BE effect captures something automatic and fundamental about our interaction with the world yet its neural substrates have not been well-characterised. The only neuropsychological study of BE was conducted recently by Mullally et al. (2012), who examined BE in patients with selective bilateral hippocampal damage and concomitant amnesia. Notably, these patients were also impaired at constructing fictitious and future scenes and events in the imagination (see also Hassabis et al., 2007; Rosenbaum

et al., 2009; click here Andelman et al., 2010; Race et al., 2011). The extrapolation of scenes beyond the view depends on intact scene construction ability (Hassabis and Maguire, 2007, 2009), Niclosamide suggesting that BE should be reduced in such patients. This is indeed what Mullally et al. (2012) found, with BE significantly attenuated compared to matched control participants across a variety of BE paradigms leading to the conclusion that the hippocampus (HC) supports the internal construction of scenes and also extended scenes when they are

not physically in view. Only one functional magnetic resonance imaging (fMRI) study has examined the neural correlates of BE, using a region-of-interest (ROI) approach focused on two scene-relevant brain areas, the posterior parahippocampal cortex (PHC) and retrosplenial cortex (RSC) (Park et al., 2007). The aim of their study was not to investigate activity relating to the initial extension of a scene during the first presentation (the BE effect), but instead was to examine neural adaptation (i.e., attenuation in the neural response with repeated presentation of a stimulus – see Grill-Spector et al., 2006) on presentation of the second scene. They found that both PHC and RSC demonstrated adaptation effects consistent with the subjective perception of scenes rather than the physical reality. The results of this study suggest that these scene-relevant regions are sensitive to the output of BE at the BE error stage. The findings from Park et al.

, 2002). Provisions under these acts range from protection of water quality and notification of ecologically sensitive areas to contributing towards conserving, maintaining,

and augmenting the floral, faunal and avifaunal biodiversity of the country’s aquatic bodies. However, the term wetland was not used specifically Metformin clinical trial in any of these legal instruments. Until the early part of 2000, the policy support for wetland conservation in India was virtually non-existent. The action on wetland management was primarily influenced by the international commitments made under Ramsar Convention and indirectly through array of other policy measures, such as, National Conservation Strategy and Policy Statement on Environment and Development, 1992; Coastal Zone Regulation Notification, 1991; National Policy and Macro level Action Strategy on Biodiversity, 1999; and National Water

Policy, 2002 (MoEF, 2007 and Prasad et al., 2002). As a signatory to Ramsar Convention on Wetlands and recognizing the importance of protecting such water bodies, the Government of India identified two sites, i.e. Chilika lake (Orissa) and Keoladeo National Park (Rajasthan), as Ramsar selleck screening library Wetlands of International Importance in 1981 (MoEF, 2012). Thereafter in 1985–1986, National Wetland Conservation

Programme (NWCP) was launched in close collaboration with concerned State Governments. Initially, only designated Ramsar Sites were identified for conservation and management under the Programme (MoEF, 2007). Several measures were taken to arrest further degradation and shrinkage of the identified water bodies due to encroachment, siltation, weed infestation, HSP90 catchment erosion, agricultural run-off carrying pesticides and fertilizers, and wastewater discharge. Subsequently in 1993, National Lake Conservation Plan (NLCP) was carved out of NWCP to focus on lakes particularly those located in urban and peri-urban areas which are subjected to anthropogenic pressures. Initially, only 10 lakes were identified for conservation and management under the plan (MoEF, 2007). There is also a National River Conservation Plan (NRCP), operational since 1995, with an objective to improve the water quality of the major Indian rivers through the implementation of pollution abatement works, to the level of designated best use.

Laccase activity measurement was performed spectrophotometrically (JASCO V/560 UV/Vis, Japan) at wavelength of 525 nm in a reaction medium containing 1 mM syringaldazine (ϵ = 65 mM−1 cm−1), 50 mM phosphate buffer pH 5 and culture filtrate. Oxidation of syringaldazine was monitored by measuring the increase in absorbance for 4 min. Enzyme activity was expressed in units (U); one unit was defined as 1 μmol of syringaldazine oxidized per min [15]. Four agricultural wastes were screened as carbon sources for ICG-001 chemical structure production of laccase. Banana peelings (dried in oven at 55 °C for 36 h), spent coffee

ground (brought from local coffee factory), rice straw and wheat bran flakes (brought from local market) were all tested. Six nitrogen sources of natural and synthetic origin were screened which are yeast extract, tryptone, malt extract, ammonium sulphate, urea and ammonium chloride. The statistical software package (Minitab 16, U.S.A) was used for designing the experiment, regression analysis of experimental data and in plotting the relation between variables. The effects of the six variables in two level form namely: malt extract (1% nitrogen content

or 2% nitrogen content), Tween-80 (0.01%(v/v) or 0.02%(v/v)), CuSO4 (0.625 mM or 1.25 mM), resorcinol (10 mg or 20 mg), dl-Methionine (5 mg or 10 mg) and tannic acid (2.5 mg or 5 mg) were assessed. The possible interactions PD0325901 between them were investigated using 32 experiments; the choice of the variables was based on the fact that the production of ligninolytic enzymes by fungi is highly regulated by nutrients [16]. The main effects of parameters on laccase production were estimated by subtracting the mean responses of parameters at their lower levels from their corresponding higher levels and divided by the total number of experimental runs. The adequacy of the model was tested and the parameters with statistically significant effects were identified using Fisher’s test for the analysis of variance

(ANOVA). The process of irradiation was PIK-5 carried out using 60Co Gamma Chamber (4000-A-India) at a dose rate 10.28 kGy/h at the time of experiment. Seven days old Pleurotus ostreatus slant about (∼8 × 106 spores/ml) was irradiated at different doses (0.1, 0.25, 0.5, 0.75, 1, 1.5 and 2 kGy) then cultivated at optimized conditions for laccase production. Non-irradiated culture was used as control. Ammonium sulphate was added to the cell free filtrate obtained from Pleurotus ostreatus to attain 80% saturation and the flask was kept at 4 °C for 48 h. Content was centrifuged at 2415 g for 15 min at 4 °C and the supernatant was discarded. The pellet was dissolved in a 50 ml, 1 mM citrate phosphate buffer pH 5. The precipitate was desalted by dialysis bag to remove low molecular weight substances and other ions that interfere with the enzyme activity as previously described [17]. Protein concentration was quantified using the Bradford assay with bovine serum albumin as standard [18].

The work demonstrates one approach by which gene expression profiling may be integrated into HHRA to support or predict apical toxicological endpoints, dose–response, and relevance check details to human diseases. Details of the mouse exposures, particle characterization and pulmonary phenotype were previously published in Bourdon et al., 2012a and Bourdon et al., 2012b. Briefly, female C57BL/6 mice were exposed to a single installation of vehicle or Printex 90 (18, 54 or 162 μg) and euthanized 1, 3 and 28 days post-exposure (n = 6/group). The intratracheal instillation

route of exposure allows for deposition of known doses directly in the lungs of the mice, and controls for potential dermal- and ingestion-related CBNP exposure that can occur during whole body inhalation exposures. The doses were selected to represent 1, 3 and 9 working days of exposure at the occupational inhalation exposure limit of 3.5 mg/m3 of CB (as established by the US Occupational Safety and Health Administration (OSHA) and the US National Institute for Occupational

Safety and Health (NIOSH))) for a mouse (assuming 1.8 L/h inhalation rate and 33.8% particle deposition in mouse, for an 8 h working day) ( Dybing et al., 1997 and Jacobsen et al., 2009). Very limited filtration of CBNPs from the nose is expected during human exposure. Printex 90 CBNPs were characterized and displayed the following properties: 14 nm primary particle size, 295–338 m2/g Brunauer Erismodegib Emmett and Teller (BET) surface area, 74.2 μg/g PAHs, 142 EU/g endotoxin, polydispersity index of 1, −10.7 mV zeta potential, 2.6 μm peak hydrodynamic number and 3.1 μm peak volume-size-distribution ( Bourdon et

al., 2012b). Analysis of pulmonary inflammatory cellular influx in bronchoalveolar lavage (BAL) revealed neutrophilic inflammation that was sustained to day 28 at all doses. Tissue-specific genotoxicity, as observed by DNA strand breaks, persisted up to day 28 at the two highest doses and FPG-sensitive sites at all doses on day 1 and the highest dose on day 3 (Bourdon et al., 2012b). Whole mouse genome DNA microarray revealed 487 and 81 differentially expressed genes (FDR adjusted p-value ≤ 0.1 and fold changes ≥ 1.5) overall in lung and liver, respectively others ( Bourdon et al., 2012a). The complete microarray dataset is available through the Gene Expression Omnibus at NCBI (http://www.ncbi.nlm.nih.gov/geo/, Superseries GSE35284, SubSeries GSE35193). This dataset was previously used to examine molecular interactions between lung and liver upon CBNP exposure ( Bourdon et al., 2012a). To determine the most affected processes of CBNP exposure, pathway analysis of gene expression data was conducted using a rank based test in R (R Development Core Team, 2011) as described in Alvo et al. (2010).

65, p<.001; t2>t4: t(13)=6.01, p<.001; t3>t4: t(13)=10.17, p<.001). (cf. Fig. 2.) Concerning the ANOVA NAME (SON vs. UN)×VOICE (FV vs. UV)×ELECTRODES (Fz vs. Cz vs. Pz)×TIME

(t1 vs. t2 vs. t3; t1=0–200 ms, t2=200–400 ms, t3=400–600 ms post-stimulus) for alpha ERD during passive listening, only a main effect for TIME (F2/26=5.71 p<.05) was significant. Post hoc tests revealed higher desynchronization in the alpha band around 400–600 ms (t3) as compared to 0–200 ms (t1) after stimulus onset (t(13)=−2.82, p<.05). To again test for hemispheric differences, an additional ANOVA including the factors NAME (SON vs. UN), VOICE (familiar voice vs. unfamiliar voice), HEMISPHERE (P3 vs. P4) and TIME (t1, t2, t3) was calculated. A significant interaction VOICE x HEMISPHERE (F1/13=5.81, p<.05) indicated that the right parietal electrode (P4) showed higher alpha ERD for stimuli spoken Erismodegib cell line in a familiar voice as compared to stimuli spoken in an unfamiliar voice (t(13)=−3.58, p<.05). In addition, the SON

as compared to UN also showed enhanced alpha ERD (NAME×HEMISPHERE×TIME: F2/26=3.80, p<.05) over the right parietal region in the last two time windows (from 200 to 400 and from 400 to 600 ms) irrespective of VOICE (t(13)=−2.25, p<.05, t(13)=−2.59, p<.05; respectively) (cf. Fig. 4 for time–frequency plot and scalp distribution). For the respective comparisons using event-related potentials please refer to Supplementary Fig. PLX4032 clinical trial 1. The ANOVA NAME×VOICE×ELECTRODES×TIME (for the factor levels please

refer to 2.4) for theta frequency yielded main effects for ELECTRODE (F2/26=22.52, p<.001) and TIME (F2/26=5.27, p<.05). Post hoc tests revealed that the electrode Pz showed less theta ERS than both Cz and Fz (t(13)=−5.87, p<.001; t(13)=−4.74, p<.001, respectively) and that theta synchronization was strongest 200–400 ms post-stimulus (t2) (t2>t1: t(13)=3.16, p<.05; t2>t3: t(13)=3.60, p<.05). The topographical distribution of theta ERS for the passive condition is also depicted in Supplementary Fig. 2. For an overview of event-related potentials in the passive condition please refer to the supplementary material (Supplementary Fig. 1). The present study focused on oscillatory brain responses to auditory name stimuli uttered by a familiar or unfamiliar voice. In the active condition, in which subjects had to count a specific target name, a higher selleck chemicals llc desynchronization in the alpha band (8–12 Hz) to target as compared to non-target stimuli was found. The response was localized around central and posterior sites and reached its maximum about 400–600 ms post-stimulus. This is coherent with previous findings showing that alpha desynchronization reflects general task demands including attentional processes (Klimesch, 1999). Considering that in our active condition subjects had to match the memorized target name to the heard name item-per-item, the result could also indicate a release of inhibition after successful matching (Klimesch, 2012).

For many VOCs very little work has been done on assessing their emission from the ocean. Anthropogenic emissions of CO2 to the atmosphere have already increased ocean acidity and this is projected to continue through this century. The uptake or emission of trace gases from the ocean is likely to change in a future higher CO2 world, since the distribution of biological communities and biological processes will be affected (Gattuso and Hansson, 2011). In order to monitor the concomitant changes in VOC concentrations for such studies,

the marine chemist will be required to frequently analyze large numbers of organic compounds in seawater, accurately and precisely even at very low concentration levels. A suitable analytical method must be sensitive, reliable, Osimertinib simple, robust, fast, reproducible, accurate, constructed to minimize biological influence and capable of measuring diverse VOCs. The most

common B-Raf mutation extraction techniques currently used for the analysis of dissolved VOCs in small volumes of marine samples are the purge-and-trap (P&T) and the solid phase microextraction (SPME) techniques. Adequate limits of detection have been reported for the first (e.g. Huybrechts et al., 2000, Kiene and Service S.K., 1991, Li et al., 2007, Orlikowska and Schulz-Bull, 2009 and Vogt et al., 2008a) and the second method (e.g. Li et al., 2010, Niki et al., 2004, Niri et al., 2008, Sakamoto et al., 2006 and Yassaa et al., 2006) in previous aqueous studies. However, further improvement in sensitivity is required due to the low marine derived VOC concentrations usually present in seawater samples. The P&T method requires that the sample stream is dried (by Nafion or chemical agents) prior to entering the concentration trap, a process that can compromise the measurement of some VOCs (e.g. oxygenated

species). The SPME method has a relatively easy sampling procedure and does not require additional 6-phosphogluconolactonase sample preparation. However, the SPME has a relatively limited coating capacity and robustness (Bigham et al., 2002 and Yassaa et al., 2006), the extraction efficiency depends on the fiber coating type and analytes used (Niri et al., 2008), and the overall analytical sensitivity cannot be further enhanced by increasing sample volumes (Bigham et al., 2002). Furthermore, the problem of competitive displacement limits the scope of VOCs that can be simultaneously sampled, meaning that a SPME method must be developed for a specific compound or family (Hudson et al., 2007 and Yassaa et al., 2006). Recently developed methods using NTDs (found in the review article (Lord et al., 2010) and more recently (Alonso et al., 2011a, Alonso et al., 2011b, Bagheri et al., 2011 and Trefz et al., 2012)) overcome these problems. In this study, appropriate sorbent packed syringes are used during extraction and concentration followed by a thermal desorption into GC systems.

This is the first report that shows the inhibition of viral replication in the cells and the involvement of IFN-α/β in the antiviral effect of lactoferrin. It has already

been reported that oral administration of lactoferrin induces IFN-α/β in the small intestine of mice [24] and [29]. From these findings, IFN-α/β may be a key mediator in the antiviral effects of orally administered lactoferrin and the deduced antiviral mechanism of lactoferrin was illustrated in Fig. 1. The effects of the oral administration of lactoferrin against viral gastroenteritis, MAPK inhibitor where rotavirus or norovirus was identified as a pathogen, have been reported (Table 2). In a study of rotaviral gastroenteritis in children, daily intake of bovine lactoferrin-containing products ameliorated the severity of the disease, although there was no significant benefit in reducing infection incidence [30]. The addition of recombinant human lactoferrin and lysozyme to a rice-based oral rehydration JQ1 mw solution had beneficial effects on children with acute diarrhea in whom rotavirus was identified as a pathogen in 18–19% of stool samples [31]. The daily administration of lactoferrin tablets

to children reduced the incidence of noroviral gastroenteritis [32]. Lactoferrin administration exhibited no decrease in diarrhea incidence, but decreased longitudinal prevalence and severity in children, where norovirus was isolated as a pathogen in 35% of diarrheal samples [33]. Recently, we performed a survey on norovirus-like gastroenteritis incidence in subjects consuming 100 mg lactoferrin-containing products including yogurt, yogurt drinks, and milk-type drinks Tau-protein kinase [34]. The results indicated a lower incidence of norovirus-like gastroenteritis in groups who frequently consumed lactoferrin products compared with groups who consumed them at a lower frequency (Fig. 2). Because there is no prophylactic

or therapeutic treatment for noroviral gastroenteritis, lactoferrin is a promising candidate to prevent infection and further studies are warranted to establish more reliable evidence. Summer colds, also called summer minor illnesses, are caused by adenoviruses and a family of viruses called enteroviruses. These have a preference for warmer weather. Adenovirus mainly causes upper and lower respiratory tract infections, but also causes diseases of the intestine, eyes, liver, urinary tract and lymphoid tissue. Adenovirus is known to cause pharyngoconjunctival fever, also called pool fever. Runny nose, nasal congestion and postnasal drainage are complaints associated with both summer and winter colds. However, enteroviruses may cause more complicated illnesses, which include fever, sore throat, hacking cough, diarrhea, and skin rash. Enteroviruses, enterovirus 71 and coxsackievirus A16, are known as common causative viral agents for hand, foot, and mouth diseases in humans.

Clinical studies have demonstrated that Hepcidin levels are inappropriately low in patients with hereditary diseases associated with iron overload, such as thalassemia, congenital dyserythropoietic anemia, and hereditary hemochromatosis [8]. Iron overload is the major cause of death in patients with thalassemia major [9] and an important cause of morbidity in transfusion-dependent patients, such as bone marrow transplant recipients [10]. Current therapies for iron overload are restricted to chelation or removing blood, phlebotomy [11]. These therapies are not well tolerated or completely effective IWR-1 chemical structure in many patients

[12]. Intriguingly, transgenic over-expression of Hepcidin in mouse models of hereditary hemochromatosis [13] or β-thalassemia [14] reduces iron overload. Thus, pharmacologically increasing Hepcidin levels may help patients with iron overload by decreasing intestinal iron absorption. Hepcidin agonists under development include Hepcidin mimics, such as rationally designed peptides (minihepcidins), and Hepcidin stimulators, such as anti-sense oligonucleotides

directed against inhibitors of Hepcidin expression, bone morphogenic protein 6 (BMP6) and small molecules therapies that activate the Stat and/or Smad pathways [12]. Chemical screens are unbiased approaches to identifying GDC-0980 cost small molecules that affect biological processes. Y-27632 2HCl They have been useful in identifying antagonists of specific pathways. For instance the bone morphogenic protein receptor 1 antagonist, dorsomorphin, was identified in a chemical screen for small molecules that affect zebrafish embryonic development [15]. Chemical screens identifying small molecules that impact specific

biological processes have improved our understanding of these processes and led to clinical trials. For instance, prostaglandin E2, was shown to be important in hematopoietic stem cell proliferation [16] and is now being evaluated in human trials to improve the efficiency of umbilical cord hematopoietic stem cell transplants [17]. In a preliminary chemical screen evaluating the effect of isoflavones and related compounds in zebrafish embryos and human hepatocytes, we identified the small molecule genistein, a phytoestrogen that is one of the major components of soybeans, as a stimulator of Hepcidin expression that activated Stat3 and Smad signaling [18]. In order to identify additional small molecules that act via different mechanisms and may have greater potency, we undertook a high throughput chemical screen for small molecules that increase Hepcidin expression in human hepatocytes. To achieve this, we generated a line of human hepatoma cells, HepG2 Hepcidin-luciferase, that express 2.7 kb of the human Hepcidin promoter upstream of a firefly luciferase reporter.

Participants who

selleck chemicals were 5 years of age or older at the time of sampling were asked to provide blood at recruitment and after each peak in confirmed case detection for paired serology. Age- and sex-standardized estimates of the risk of influenza infection and illness per season in persons 5 years of age or older were reported previously.21 Three influenza seasons were identified in this study period (Table 1). The number of people that provided blood samples spanning each season, the numbers infected as determined by serology and RT-PCR, and their age distribution is shown as supplementary information (Fig. S1). Males, and participants aged less than 5 or in their late teens were under-represented in the group that could be analyzed (Fig. S1). Genetic and antigenic characterization of the viruses isolated and used for serology is shown in supplementary information (Fig. S2 and Table S1). The H1N1 viruses isolated in season one (S1) in 2008 were A/Brisbane/59/2007-like, and B

virus isolates were of the B-Yamagata-lineage and were B/Florida/4/2006-like, representing strains that were antigenically distinct from the pre-study season. The H3N2 viruses isolated in S1 were antigenically A/Brisbane/10/2007-like, as in the pre-study season, and caused few infections. The H3N2 viruses isolated in the second season (S2) in Spring 2009 were antigenically distinct A/Perth/16/2009-like strains, and caused the highest incidence of infection, whereas two

H1N1 isolates were similar to the S1 isolate. HI titers with WHO reference sera against seasonal H1N1 selleck screening library were 1280 against the 2008 H1N1 isolate and 640 against both 2009 H1N1 isolates. The only B virus isolated in 2009 belonged to the B-Victoria lineage, ID-8 and the National Influenza surveillance system identified a shift in B-lineage predominance from Yamagata to Victoria in 2009. However serology was only performed with a Yamagata lineage virus. The third season (S3) in Autumn 2009, was caused by the pandemic H1N1 2009 strain (A/California/04/2009), which resulted in a high incidence of infection compared to individual seasonal strains. It was not feasible to collect swabs from all cohort participants weekly; hence infections were also identified by HI antibody seroconversion. As in our previous report, seroconversion was defined as at least a 4-fold rise in titer with a post-season titer of at least 40.21 We have recently reported that the pattern of 2-fold increases in HI titer cannot be fully explained by assay variability, and that a reliance on four-fold titer increases to define infection may under estimate the true incidence of infection.24 However, since it is not possible to adjust for assay variability in an individual level analysis we did not apply a 2-fold definition.