No effects of mobile phone use on cortical auditory change‐detection in children: An ERP study

We investigated the effect of mobile phone use on the auditory sensory memory in children. Auditory event‐related potentials (ERPs), P1, N2, mismatch negativity (MMN), and P3a, were recorded from 17 children, aged 11–12 years, in the recently developed multi‐feature paradigm. This paradigm allows one to determine the neural change‐detection profile consisting of several different types of acoustic changes. During the recording, an ordinary GSM (Global System for Mobile Communications) mobile phone emitting 902 MHz (pulsed at 217 Hz) electromagnetic field (EMF) was placed on the ear, over the left or right temporal area (SAR_1g = 1.14 W/kg, SAR_10g = 0.82 W/kg, peak value = 1.21 W/kg). The EMF was either on or off in a single‐blind manner. We found that a short exposure (two 6 min blocks for each side) to mobile phone EMF has no statistically significant effects on the neural change‐detection profile measured with the MMN. Furthermore, the multi‐feature paradigm was shown to be well suited for studies of perception accuracy and sensory memory in children. However, it should be noted that the present study only had sufficient statistical power to detect a large effect size. Bioelectromagnetics 31:191–199, 2010. © 2009 Wiley‐Liss, Inc.     

Effect of a 902 MHz electromagnetic field emitted by mobile phones on human cognitive function: A replication study

Our study was a replication and extension with methodological improvements to a previous study on effects of the electromagnetic field (EMF) emitted by a 902 MHz mobile phone on human cognitive functioning. Improvements on the previous study included multicentre testing and a double blind design. A total of 64 subjects (32 men and 32 women) in two independent laboratories performed a battery of 9 cognitive tasks twice: while the EMF was on and while it was off. Reaction times (RTs) and accuracy were recorded. The order of exposure and tasks was counterbalanced across subjects and gender. There were no statistically significant differences in performance between genders or laboratories. Although the RTs and the accuracy of answers were very similar to those of our previous study, our previous results were not replicated. We concluded that EMF had no effect on RTs or on the accuracy of the subjects' answers. Further, our results indicate that our EMF had no immediate effect on human cognitive functioning or that such effects are so small that they are observed on behavior only occasionally.     

Effects of weak mobile phone - electromagnetic fields (GSM, UMTS) on event related potentials and cognitive functions

Modern mobile phones emit electromagnetic fields (EMF) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. Until now most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies have focused on Universal Mobile Telecommunications System (UMTS)-EMF. Therefore, we tested the effects of both types of unilaterally presented EMF, 1950 UMTS (0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on visually evoked occipital P100, the P300 of a continuous performance test, auditory evoked central N100 and the P300 during an oddball task as well as on the respective behavioral parameters, reaction time and false reactions, in 15 healthy, right handed subjects. A double-blind, randomized, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.     

Human electrophysiological and cognitive effects of exposure to ELF magnetic and ELF modulated RF and microwave fields: a review of recent studies

The investigation of weak (<500 microT), extremely low frequency (ELF, 0-300 Hz) magnetic field (MF) exposure upon human cognition and electrophysiology has yielded incomplete and contradictory evidence that MFs interact with human biology. This may be due to the small number of studies undertaken examining ELF MF effects upon the human electroencephalogram (EEG), and the associated analysis of evoked related potentials (ERPs). Relatively few studies have examined how MF exposure may affect cognitive and perceptual processing in human subjects. The introduction of this review considers some of the recent studies of ELF MF exposure upon the EEG, ERPs and cognitive and perceptual tasks. We also consider some of the confounding factors within current human MF studies and suggest some new strategies for further experimentation.     

Cytotoxicity of carboplatin on human glioblastoma cells is reduced by the concomitant exposure to an extremely low-frequency electromagnetic field (50 Hz, 70 G)

Glioblastoma multiforme (GBM) is a malignant brain cancer that causes high mortality in patients. GBM responds weakly to the common cancer treatments such as chemotherapy and radiotherapy and even surgery. Carboplatin is an alkylating agent widely used to treat cancer. However, resistance to this drug is a common problem in its use in cancer treatment. Concomitant exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) and carboplatin is one unexplored possibility for overcoming this resistance. Indeed, many lines of evidence show that EMF affects cancer cells and drug action. In this study, we evaluated the effect of concomitant administration of carboplatin and EMF (50 Hz, 70 G) and also concomitant administration of carboplatin and static magnetic field (SMF) (70 G) on human glioma cell line (U-87). The results showed that cotreatment reduced the efficiency of carboplatin in U-87 cells, by decreasing caspase-3 in comparison to drug groups. Overall, EMF reduced the apoptotic effect of carboplatin, possibly through a redox regulation mechanism. Therefore, we have to avoid coadministration of magnetic field (MF) and carboplatin in tumor area, because the MF decreased the toxicity of the drug. However, further studies are needed to reveal the action mechanism of this combination therapeutic method.     

Effects of high frequency electromagnetic field (EMF) emitted by mobile phones on the human motor cortex

We investigated whether the pulsed high frequency electromagnetic field (EMF) emitted by a mobile phone has short term effects on the human motor cortex. We measured motor evoked potentials (MEPs) elicited by single pulse transcranial magnetic stimulation (TMS), before and after mobile phone exposure (active and sham) in 10 normal volunteers. Three sites were stimulated (motor cortex (CTX), brainstem (BST) and spinal nerve (Sp)). The short interval intracortical inhibition (SICI) of the motor cortex reflecting GABAergic interneuronal function was also studied by paired pulse TMS method. MEPs to single pulse TMS were also recorded in two patients with multiple sclerosis showing temperature dependent neurological symptoms (hot bath effect). Neither MEPs to single pulse TMS nor the SICI was affected by 30 min of EMF exposure from mobile phones or sham exposure. In two MS patients, mobile phone exposure had no effect on any parameters of MEPs even though conduction block occurred at the corticospinal tracts after taking a bath. As far as available methods are concerned, we did not detect any short-term effects of 30 min mobile phone exposure on the human motor cortical output neurons or interneurons even though we can not exclude the possibility that we failed to detect some mild effects due to a small sample size in the present study. This is the first study of MEPs after electromagnetic exposure from a mobile phone in neurological patients.     

Absence of daytime 50 Hz, 100 microT(rms) magnetic field or bright light exposure effect on human performance and psychophysiological parameters

The purpose of this study was to reproduce and extend two earlier studies of the effects of human exposure to 50 Hz magnetic fields (MF). In a recent paper, we described results of two double-blind investigations performed to examine effects of 100 microT(rms) 50 Hz MF exposure on psychological parameters in the same group of healthy human volunteers. In each exposure session, at 1 week intervals, with sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, mood ratings, performance measures, and electrophysiological measures were taken. In the first study, significant amplitude changes were observed in the event-related brain potentials (ERP) recorded during a dichotic listening task. In the second study, latency and reaction time (RT) slowing were seen on a visual discrimination task (P(300) paradigm). Although these results were little related to the number of parameters analysed, they indicate that low level 50 Hz MF might have a slight influence on ERP and RT under specific circumstances of sustained attention. Before concluding that moderately strong MF exposure can influence cognitive function, previous results should be replicated, using the same paradigms with another group of healthy volunteers. In the present study, 18 healthy subjects were exposed to three experimental sessions of 30 min each, given at 1 week intervals. The sessions consisted of continuous 100 microT(rms) 50 Hz MF exposure, sham condition, and bright light (5000 lux) exposure. The study was performed double-blind, with the exposure order counter-balanced. The data on mood, ERP, RT, and other performance measures did not show any differences among the sham exposure, light exposure, and MF exposure conditions. The results of this study do not support the hypothesis that extremely low frequency (ELF) MF exposure affects the brain's electrical activity or cognitive function at field strength (100 microT(rms)) similar to that found in very close proximity of some household and industrial electrical appliances and well in excess of the average MF strength (c. 0.1 microT) found in homes. The sensitivity of the experiment was possibly not sufficient to detect an effect at this relatively low MF, and larger sample sizes would be required in further studies.     

Therapeutic effects of whole‐body devices applying pulsed electromagnetic fields (PEMF): A systematic literature review

Pulsed electromagnetic fields (PEMF) delivered by whole‐body mats are promoted in many countries for a wide range of therapeutic applications and for enhanced well‐being. However, neither the therapeutic efficacy nor the potential health hazards caused by these mats have been systematically evaluated. We conducted a systematic review of trials investigating the therapeutic effects of low‐frequency PEMF devices. We were interested in all health outcomes addressed so far in randomized, sham‐controlled, double‐blind trials. In total, 11 trials were identified. They were focused on osteoarthritis of the knee (3 trials) or the cervical spine (1), fibromyalgia (1), pain perception (2), skin ulcer healing (1), multiple sclerosis‐related fatigue (2), or heart rate variability and well‐being (1). The sample sizes of the trials ranged from 12 to 71 individuals. The observation period lasted 12 weeks at maximum, and the applied magnetic flux densities ranged from 3.4 to 200 µT. In some trials sporadic positive effects on health were observed. However, independent confirmation of such singular findings was lacking. We conclude that the scientific evidence for therapeutic effects of whole‐body PEMF devices is insufficient. Acute adverse effects have not been reported. However, adverse effects occurring after long‐term application have not been studied so far. In summary, the therapeutic use of low‐frequency whole‐body PEMF devices cannot be recommended without more scientific evidence from high‐quality, double‐blind trials. Bioelectromagnetics 33:95–105, 2012. © 2011 Wiley Periodicals, Inc.     

Exposure to ELF magnetic and ELF-modulated radiofrequency fields: the time course of physiological and cognitive effects observed in recent studies (2001-2005)

In 2002, we published a review of the cognitive and physiological effects of extremely low frequency magnetic fields (ELF MFs) and ELF-modulated radiofrequency fields associated with mobile phones. Since the original preparation of that review, a significant number of studies have been published using techniques such as electroencephalography, event-related potentials and positron emission tomography to investigate electromagnetic field effects upon human physiology and various measures of performance (cognitive, perceptual, behavioral). We review these recent studies, and when effects were observed, we reference the time course of observed effects (immediate or delayed). In our concluding remarks, we discuss a number of variables that are not often considered in human bioelectromagnetics studies, such as personality, individual differences and the specific laterality of ELF MF and mobile phone exposure over the brain. We also consider the sensitivity of various physiological assays and performance measures in the study of biological effects of electromagnetic fields.     

Electrochemical optical waveguide lightmode spectroscopy (EC-OWLS): a pilot study using evanescent-field optical sensing under voltage control to monitor polycationic polymer adsorption onto indium tin oxide (ITO)-coated waveguide chips

A new technique has been developed that combines evanescent-field optical sensing with electrochemical control of surface adsorption processes. This new technique, termed "electrochemical optical waveguide lightmode spectroscopy" (EC-OWLS), proved efficient in monitoring molecular surface adsorption and layer thickness changes of an adsorbed polymer layer examined in situ as a function of potential applied to a waveguide in a pilot study. For optical sensing, a layer of indium tin oxide (ITO) served as both a high-refractive-index waveguide and a conductive electrode. In addition, an electrochemical flow-through fluid cell was provided, which incorporated working, reference, and counter electrodes, and was compatible with the constraints of optical sensing. Poly(L-lysine)-grafted-poly(ethylene glycol) (PLL-g-PEG) served as a model, polycation adsorbate. Adsorption of PLL-g-PEG from aqueous buffer solution increased from 125 to 475 ng/cm(2 )along a sigmoidal path as a function of increasing potential between 0 and 1.5 V versus the Ag reference electrode. Upon buffer rinse, adsorption was partially reversible when a potential of >/=0.93 V was maintained on the ITO waveguide. However, reducing the applied potential back to 0 V before rinsing resulted in irreversible polymer adsorption. PLL-g-PEG modified with biotin demonstrated similar adsorption characteristics, but subsequent streptavidin binding was independent of biotin concentration. Applying positive potentials resulted in increased adsorbed mass, presumably due to polymer chain extension and reorganization in the molecular adlayer.     

Ovarian Stem Cells (OSCs) from the Cryopreserved Ovarian Cortex: A Potential for Neo-Oogenesis in Women with Cancer-Treatment Related Infertility: A Case Report and a Review of Literature

Cancer treatment related infertility (CTRI) affects more than one third of young women undergoing anti-cancer protocols, inducing a premature exhaustion of the ovarian reserve. In addition to ovarian suppression by GnRHa, oocyte and cortex cryopreservation has gained interest in patients with estrogen-sensitive tumors for whom the hormonal burst to prompt the multiple follicular growth could provide a further pro-life tumor pulsing. On the other hand, cortex reimplantation implies a few drawbacks due to the unknown consistency of the follicles to be reimplanted or the risk of reintroducing malignant cells. The capability of ovarian stem cells (OCSs) from fresh ovarian cortex fragments to differentiate in vitro to mature oocytes provides a tool to overcome these drawbacks. In fact, since ovarian cortex sampling and cryopreservation is practicable before gonadotoxic treatments, the recruitment of OSCs from defrosted fragments could provide a novel opportunity to verify their suitability to be expanded in vitro as oocyte like cells (OLCs). Here, we describe in very preliminary experiments the consistency of an OSC population from a single cryopreserved ovarian cortex after thawing as well as both their viability and their suitability to be further explored in their property to differentiate in OLCs, thus reinforcing interest in stemness studies in the treatment of female CTRI.     

Reflecting conifer phenology using mobile terrestrial LiDAR: A case study of Pinus sylvestris growing under the Mediterranean climate in Perth,Australia

Accurately monitoring of tree phenological dynamics is crucial for understanding how forest ecosystems respond to various climate changes, and a variety of methods recently have been established for accomplishing this task. However, efficient techniques for featuring conifer phenology are still lacking. In fact, characterizing conifer phenological variations have long been an issue, because conifers tend to show hard-to-discern changes in terms of no matter color or crown morphology for different seasons. To address this conventional ⿿conifer issue⿿, this study attempted the state-of-the-art remote sensing technology of mobile terrestrial light detection and ranging (LiDAR) (also termed as mobile terrestrial laser scanning, MLS) to reflect the seasonal-scale phenological variations of conifers, specifically in a case of Scots pines (Pinus sylvestris) growing under the Mediterranean climate in Perth, Australia. The MLS-collected data shows that for the conifers growing under different temperature and precipitation conditions, lasers, in a statistical sense, behave with different penetrations into their crowns. In light of this phenomenon, a new seasonal-scale conifer phenological indicator (CsPI) was proposed, i.e. the ratio between the average of the horizontal penetration distances for the entire laser points backscattered from a crown and its diameter calculated along with the horizontal direction of laser incidence. The performance of the newly-proposed CsPI was assessed by the means of meta-analysis, i.e. comparing the CsPI-indicated conifer response to seasonal climate changes in Perth with the derived rule of stem radial growth rates at different seasons in Mesic, Spain, both in the Mediterranean climate scenarios. The correlations with positive results showed that the proposed schematic plan of applying MLS and the developed phenological indicator both are validated, and this study has opened a new way for reflecting the seasonal-scale phenological variations of conifers.     

Responses of four submerged macrophytes to freshwater snail density (Radix swinhoei) under clear‐water conditions: A mesocosm study

Macrophytes play a key role in stabilizing clear‐water conditions in shallow freshwater ecosystems. Their populations are maintained by a balance between plant grazing and plant growth. As a freshwater snail commonly found in shallow lakes, Radix swinhoei can affect the growth of submerged macrophytes by removing epiphyton from the surface of aquatic plants and by grazing directly on macrophyte organs. Thus, we conducted a long‐term (11‐month) experiment to explore the effects of snail density on macrophytes with distinctive structures in an outdoor clear‐water mesocosm system (with relatively low total nitrogen (TN, 0.66 ± 0.27 mg/L) and total phosphorus (TP, 36 ± 20 μg/L) and a phytoplankton chlorophyll a (Chla) range of 14.8 ± 4.9 μg/L) based on two different snail densities (low and high) and four macrophyte species treatments (Myriophyllum spicatum, Potamogeton wrightii, P. crispus, and P. oxyphyllus). In the high‐density treatment, snail biomass and abundance (36.5 ± 16.5 g/m² and 169 ± 92 ind/m², respectively) were approximately twice that observed in the low‐density treatment, resulting in lower total and aboveground biomass and ramet number in the macrophytes. In addition, plant height and plant volume inhabited (PVI) showed species‐specific responses to snail densities, that is, the height of P. oxyphyllus and PVI of M. spicatum were both higher under low‐density treatment. Thus, compared with low‐density treatment, the inhibitory effects of long‐term high snail density on macrophytes by direct feeding may be greater than the positive effects resulting from epiphyton clearance when under clear‐water conditions with low epiphyton biomass. Thus, under clear‐water conditions, the growth and community composition of submerged macrophytes could be potentially modified by the manual addition of invertebrates (i.e., snails) to lakes if the inhibitory effects from predatory fish are minor.     

Phosphodiesterase MoPdeH targets MoMck1 of the conserved mitogen‐activated protein (MAP) kinase signalling pathway to regulate cell wall integrity in rice blast fungus Magnaporthe oryzae

In the rice blast fungus Magnaporthe oryzae, the high‐affinity cyclic adenosine monophosphate (cAMP) phosphodiesterase MoPdeH is important not only for cAMP signalling and pathogenicity, but also for cell wall integrity (CWI) maintenance through an unknown mechanism. By utilizing affinity purification, we found that MoPdeH interacts with MoMck1, one of the components of the mitogen‐activated protein (MAP) kinase cascade that regulates CWI. Overexpression of MoMCK1 suppressed defects in autolysis and pathogenicity of the ΔMopdeH mutant, although partially, suggesting that MoPdeH plays a critical role in CWI maintenance mediated by the MAP kinase pathway. We found that MoMck1 and two other MAP kinase cascade components, MoMkk1 and MoMps1, modulate intracellular cAMP levels by regulating the expression of MoPDEH through a feedback loop. In addition, disruption of MoMKK1 resulted in less aerial hyphal formation, defective asexual development and attenuated pathogenicity. Moreover, MoMkk1 plays a role in the response to osmotic stress via regulation of MoOsm1 phosphorylation levels, whereas endoplasmic reticulum (ER) stress enhances MoMps1 phosphorylation and loss of the MAP kinase cascade component affects the unfolded protein response (UPR) pathway. Taken together, our findings demonstrate that MoPdeH functions upstream of the MoMck1–MoMkk1–MoMps1 MAP kinase pathway to regulate CWI, and that MoPdeH also mediates crosstalk between the cAMP signalling pathway, the osmotic sensing high osmolarity glycerol (HOG) pathway and the dithiothreitol (DTT)‐induced UPR pathway in M. oryzae.     

High‐efficient and precise base editing of C•G to T•A in the allotetraploid cotton (Gossypium hirsutum) genome using a modified CRISPR/Cas9 system

The base‐editing technique using CRISPR/nCas9 (Cas9 nickase) or dCas9 (deactivated Cas9) fused with cytidine deaminase is a powerful tool to create point mutations. In this study, a novel G. hirsutum‐Base Editor 3 (GhBE3) base‐editing system has been developed to create single‐base mutations in the allotetraploid genome of cotton (Gossypium hirsutum). A cytidine deaminase sequence (APOBEC) fused with nCas9 and uracil glycosylase inhibitor (UGI) was inserted into our CRISPR/Cas9 plasmid (pRGEB32‐GhU6.7). Three target sites were chosen for two target genes, GhCLA and GhPEBP, to test the efficiency and accuracy of GhBE3. The editing efficiency ranged from 26.67 to 57.78% at the three target sites. Targeted deep sequencing revealed that the C→T substitution efficiency within an ‘editing window’, approximately six‐nucleotide windows of ?17 to ?12 bp from the PAM sequence, was up to 18.63% of the total sequences. The 27 most likely off‐target sites predicted by CRISPR‐P and Cas‐OFFinder tools were analysed by targeted deep sequencing, and it was found that rare C→T substitutions (average < 0.1%) were detected in the editing windows of these sites. Furthermore, whole‐genome sequencing analyses on two GhCLA‐edited and one wild‐type plants with about 100× depth showed that no bona fide off‐target mutations were detectable from 1500 predicted potential off‐target sites across the genome. In addition, the edited bases were inherited to T1 progeny. These results demonstrate that GhBE3 has high specificity and accuracy for the generation of targeted point mutations in allotetraploid cotton.     

Estimating the risk of PTSD in recent trauma survivors: results of the International Consortium to Predict PTSD (ICPP)

A timely determination of the risk of post‐traumatic stress disorder (PTSD) is a prerequisite for efficient service delivery and prevention. We provide a risk estimate tool allowing a calculation of individuals’ PTSD likelihood from early predictors. Members of the International Consortium to Predict PTSD (ICPP) shared individual participants’ item‐level data from ten longitudinal studies of civilian trauma survivors admitted to acute care centers in six countries. Eligible participants (N=2,473) completed an initial clinical assessment within 60 days of trauma exposure, and at least one follow‐up assessment 4‐15 months later. The Clinician‐Administered PTSD Scale for DSM‐IV (CAPS) evaluated PTSD symptom severity and diagnostic status at each assessment. Participants’ education, prior lifetime trauma exposure, marital status and socio‐economic status were assessed and harmonized across studies. The study's main outcome was the likelihood of a follow‐up PTSD given early predictors. The prevalence of follow‐up PTSD was 11.8% (9.2% for male participants and 16.4% for females). A logistic model using early PTSD symptom severity (initial CAPS total score) as a predictor produced remarkably accurate estimates of follow‐up PTSD (predicted vs. raw probabilities: r=0.976). Adding respondents’ female gender, lower education, and exposure to prior interpersonal trauma to the model yielded higher PTSD likelihood estimates, with similar model accuracy (predicted vs. raw probabilities: r=0.941). The current model could be adjusted for other traumatic circumstances and accommodate risk factors not captured by the ICPP (e.g., biological, social). In line with their use in general medicine, risk estimate models can inform clinical choices in psychiatry. It is hoped that quantifying individuals’ PTSD risk will be a first step towards systematic prevention of the disorder.     

A Simulation model for the arrowhead scale (Hemiptera: Diaspididae) population dynamics on citrus trees in relation to pest-management programs

1. A mathematical model was constructed describing population dynamics of the arrowhead scale, Unaspis yanonensis Kuwana. The population occurrence patterns simulated by the model from 1971 to 1976 were relatively consistent with the actual findings in the field.
2. The effects of control tactics for this pest were examined on the basis of the model.
3. Effective timing of insecticide (petroleum oil and organophosphorous insecticide) application was indicated to be 40 days after the initial appearance of 1st-instar nymphs in both the 1st and 2nd generations of the host.
4. The number of overwintering adult females in May of the next year (i.e., the starting point of the next year's population) decreased linearly with the increment in the degree of insecticide coverage. The pest populations were expected to be kept to low densities by petroleum oil sprays alone for the 1st generation when overall, complete coverage was accomplished.
5. Examination of the effects of two introduced parasitoids, Aphytis yanonensis and Coccobius fulvus, showed that they were able to control the scale population by themselves when more than 70% parasitism was achieved. When petroleum oil was applied to overwintering adults (termed winter petroleum oil) at the degree of coverage of 0.8, host populations were reduced by ca. 60% parasitism. When the winter petroleum oil was combined either with additional petroleum oil 40 days after the initial appearance of 1st-instar nymphs of the 1st generation or with an organophosphorous insecticide 40 days after the initial appearance of 1st-instar nymphs of the 2nd generation (degree of coverage=0.8 in each case), 40% parasitism led the reduction of the pest population.
6. The most desirable control program was considered to be one in which winter petroleum oil was used every year and additional petroleum oil or an organophosphorous insecticide was also used in those years when host density was high.

     

Cross‐reactive antibody response to the pandemic A (H1N1) 2009 influenza virus induced by vaccination with a seasonal trivalent influenza vaccine: a longitudinal study of three influenza seasons in Japan

The cross‐reactivity of antibody to the swine‐origin pandemic influenza A (H1N1) 2009 virus induced by vaccination with a seasonal trivalent influenza vaccine was studied. Paired sera from a cohort of adult volunteers vaccinated with a trivalent seasonal influenza vaccine every year from 2006 to 2008 were collected each year and tested by hemagglutination inhibition (HI) for antibody against the pandemic influenza A (H1N1) 2009 virus. There was little increase in the geometric mean titer overall; a slight increase was detected in the sera obtained in the 2007–2008 season but not in the other two seasons. The proportion of individuals with HI antibody titers ≥ 1:40 did not change significantly from year to year. These results indicate that cross‐reactivity of the antibodies induced by a trivalent seasonal vaccine to the pandemic influenza A (H1N1) 2009 virus is marginal.     

A validated HPLC method for the determination of dimethyl‐4,4′‐dimethoxy‐5,6,5′,6′‐dimethylene dioxybiphenyl‐2,2′‐dicarboxylate (DDB) with fluorescence detection in raw material and pill form: application to an in vitro dissolution test and a content uniformity test

A simple, sensitive and rapid HPLC method with fluorescence detection for the determination of dimethyl‐4,4′‐dimethoxy‐5,6,5′,6′‐dimethylene dioxybiphenyl‐2,2′‐dicarboxylate (DDB) in the raw material and pill form was developed. Liquid chromatography was performed on a C₁₈ column (250 × 4.6 mm i.d., 5 µm particle size), the mobile phase consisted of methanol and 0.05 M sodium dihydrogen phosphate buffer (80 : 20, v/v), and the apparent pH of the mobile phase was adjusted to 3. The fluorescence detector was operated at excitation/emission wavelengths of 275/400 nm. The proposed method allows the determination of DDB within concentration range 0.1–1.5 µg/mL with a limit of detection of 0.032 µg/mL, a limit of quantification of 0.097 µg/mL and a correlation coefficient of 0.9997. The proposed method has been successfully applied for the analysis of DDB in its pills with a percentage recovery of 98.45 ± 0.32. The method was fully validated according to ICH guidelines. Moreover, the high sensitivity of the method permits its use in an in vitro dissolution test for DDB under simulated intestinal conditions. In addition, the proposed method was extended to a content uniformity test according to USP guidelines. Copyright © 2014 John Wiley & Sons, Ltd.