“Lung cancer, the leading cause of cancer death world wide


“Lung cancer, the leading cause of cancer death world wide, is classified histologically to small-cell (15%) or non-small-cell (85%). Non-small-cell lung cancer (NSCLC) is further divided into 3 subtypes based on histology: squamous-cell carcinoma, adenocarcinoma, and large-cell lung cancer. As surgical techniques and combination treatment regimens have improved, the 1-year survival rate in lung cancer has increased slightly, from 35% in 1975–1979 to 41% in 2000–2003. Nonetheless, the 5-year survival rate for all stages of lung Sotrastaurin concentration cancer combined remains around 15%. The majority of patients with NSCLC are candidates for systemic treatment with chemotherapy,

either as therapy for advanced disease or as adjuvant or neoadjuvant treatment with local therapy (surgery or radiation therapy) utilized in earlier stages. However, chemotherapy has only shown modest

improvement in the outcome of NSCLC [1]. Chemotherapy normally yields 30% response, 4 months PFS and median survival of 8–11 months. Therefore, new treatment approaches are needed. Targeting the epidermal growth factor receptor (EGFR) and vascular endothelial inhibitor (VGEF) has played a central role in advancing NSCLC research, treatment, and patient outcome over the last several years [2]. This manuscript focuses on the role of EGFR in NSCLC and current clinical data on agents targeting the EGFR pathway, and recent advances in using EGFR ABT-263 chemical structure inhibitor in clinical practice. The human genome encodes approximately 518 kinases, of which there are 90 Tyrosine kinases (TKs) and 43 tyrosine-like kinases. EGFR, – a 170-kDa (1186 amino acid) membrane-bound protein encoded by 28 exons spanning nearly 190,000 nucleotides on chromosome 7p12, is one member of the TK family, which belongs to a subfamily of four closely related

receptors: HER-1/ErbB1, HER-2/neu/ErbB2, HER-3/ErbB3, and HER-4/ErbB4. Structurally, EGFR receptor is composed of an extracellular ligand binding domain, a transmembrane domain, and an intracellular domain. Upon binding to ligands, such as epidermal growth factor (EGF), the receptors undergo conformational changes that facilitate intermolecular autophosphorylation which activate Protein kinase N1 EGFR pathways which are important for cell survival, and the mitogen-activated protein kinase (MAPK) pathway, which induces proliferation. EGFR regulates important tumorigenic processes that include proliferation, apoptosis, angiogenesis, and invasion [3] and [4]. The epidermal growth factor receptor is a tyrosine kinase (TK) receptor of the ErbB family that is commonly altered in epithelial tumors. EGFR was shown to be an oncogene, capable of inducing cancer when aberrant. So using specific monoclonal antibodies against the EGFR could inhibit its activity. Since EGFR appeared to play a central role in tumorigenesis, this observation implied that targeting the receptor itself might be an effective way to treat EGFR-expressing cancers [3] and [4].

(2011) Fish, corals, and other invertebrates (Table 2) were coll

(2011). Fish, corals, and other invertebrates (Table 2) were collected from Bantayan Reef, Dumaguete (9° 19′ 56.1″ N, 123° 18′ 38.06″ E) across the SU-IEMS Marine Laboratory. Fish were collected by local fishermen using hand nets and fish traps. Experiments were conducted using four concrete tanks (3 m long × 1 m wide × 0.5 m deep) with

flow-through seawater at ambient conditions (mean temperature = 28 °C, salinity = 33 ppt, pH = 8.3). Half of each coral colony was find more enclosed in a wire cage to ensure that a portion of every coral survived despite feeding activities of newly introduced A. planci ( Fig. 1). Coral fragments and colonies (∼15 cm L × W × H) were arranged in a way that the least preferred species were closest to the seawater inlet and the injected sea stars, while the most preferred species were farthest ( Pratchett, 2007). Fish and mobile invertebrates were also placed in the tanks. Eight sea stars see more were separated in pairs and one A. planci was injected

with 10 ml oxgall (8 g l−1), oxgall (4 g l−1), peptone (20 g l−1), and TCBS (44 g l−1) at day 1 and the remaining one at day 4. All starfish were placed near the seawater inlet of Tanks 1–4, respectively. Interaction between all the animals in the tank was recorded for 4 h in the morning and 4 h in the afternoon using a GoPro Hero 2 HD video camera. Signs of disease such as darkened coloration to the skin and fins, erythema, changes to the eyes such as distension and cloudiness, periorbital swelling, haemorrhagic septicaemia and mortality were monitored every 8 h for 12 days. Mortality rates Adenosine triphosphate were highest in individuals injected

with bile derivatives (bile salts, oxgall) and TCBS, while mortality rates in peptones were moderate and only increased when concentrations were raised to 10–20× the standard concentration based on manufacturer formulation of TCBS (Fig. 2). Severity of clinical signs, mentioned hereafter, will range from low (i.e. localized to site of injection) to high (i.e. spread to more than 50% of the sea star). At the TCBS standard concentration of 10 g l−1, there was 0% mortality up to 48 h using Oxoid brand and only one 1 out of 10 A. planci died using Himedi brand. Most A. planci showed localized loss of turgor, matting, and mucus secretion. At half the TCBS standard concentration (5 g l−1), 50% of the sea stars showed loss of turgor and swelling after 8 h, but all recovered after 48 h and there was 0% mortality. At twice (20 g l−1) the TCBS standard concentration, 4 out of 10 exhibited localized tissue necrosis and 2 out of 10 sea stars showed medium severity necrosis at 8 h. After 24 h, 6 out of 10 showed medium severity necrosis and 1 out of 10 with localized necrosis.

The request by authorities to remove thiomersal caused fear among

The request by authorities to remove thiomersal caused fear amongst the general public concerning the toxicity of vaccine components, and negatively impacted overall vaccine uptake and acceptance. In the subsequent years, following authority guidance, vaccine manufacturers have removed thiomersal from most paediatric vaccines and reduced the amount of thiomersal in the few remaining vaccine formulations in a common effort to remove mercury from vaccines and re-establish public confidence in immunisation programmes. However, the WHO acknowledges that making changes to the thiomersal content of licensed

vaccines containing this preservative is a complex issue requiring careful consideration. Any change in the formulation of thiomersal-containing vaccines may

selleck inhibitor have an important impact on the quality, safety and efficacy of the vaccine Ibrutinib order and therefore any decision regarding the elimination or reduction of thiomersal in vaccines should be based on a demonstrated adverse effect. New-generation vaccines are subject to increased safety testing throughout the vaccine development process. The safety assessment has been enhanced throughout preclinical, clinical and post-licensure studies. All safety assessments performed have the objective of increasing the likelihood of identifying possible safety concerns and consequently of taking the necessary measures to remove or minimise them. Available data indicate that licensed vaccines have a benefit–risk profile where the benefits clearly surpass the risks. This short overview of vaccine development processes and post-licensure surveillance describes how clinical development and assessment of vaccines is constantly improving and evolving. It also illustrates second how changes to the processes over time have helped to

generate the robust data needed to enhance the benefit–risk profiles of new vaccines. There is now a large number of diseases for which licensed vaccines are available (Appendices, Supplementary Table 6), however, we are still faced with challenges in the form of diverse populations and complex pathogens; these require further novel approaches to antigen selection, manufacture, presentation and delivery. The main areas of new vaccine research are the subject of Chapter 6 – Vaccines of the future. “
“Key concepts ■ New tools are available to aid vaccine manufacturers in meeting challenges for new vaccine development □ Many technologies that are already available continue to be improved, including adjuvants and novel vaccine delivery platforms The advances made in vaccine technology since Edward Jenner vaccinated the young James Phipps against smallpox have had a spectacular impact on human health over the last two centuries (see Chapter 1 – Vaccine evolution).

In agreement with other studies,7, 24 and 25 our data suggest tha

In agreement with other studies,7, 24 and 25 our data suggest that RA is not sufficient to cause enhanced Foxp3+ iTreg induction by CD103+ intestinal DCs, and we now show that RA can be dispensable for this function. Because enhanced iTreg induction by intestinal CD103+ DCs is wholly dependent on their enhanced ability to activate TGF-β, an important question therefore is what are the physiologic situations when RA can act to enhance iTreg conversion in vivo? Studies

have shown that RA acts Afatinib purchase through the RARα receptor expressed on T cells to enhance TGF-β–mediated Foxp3 induction26, 27, 28 and 29 but that mice lacking RARα show normal Foxp3+ Treg levels in the lamina propria.27 Also, mice fed a vitamin A–deficient diet from birth do not show reduced Foxp3+ Treg DAPT nmr numbers in the gut, at least in the small intestine.30 These data suggest that the role of RA in regulating steady-state levels of Foxp3+ Tregs in the gut is minimal. This is in contrast to the role of integrin αvβ8-mediated TGF-β activation,

because mice lacking this TGF-β–activating integrin on DCs not only show reduced levels of lamina propria Foxp3+ Tregs, but also develop severe colitis under steady-state conditions.9 It is conceivable that RA acts to enhance Foxp3+ iTreg induction by CD103+ intestinal DCs when TGF-β levels are up-regulated (eg, during the course of infection and inflammation).31 An important function of RA is its ability to inhibit TGF-β–driven induction of proinflammatory IL-17–producing Th17 cells.25 Interestingly, our recent data and that of others have highlighted an important role for integrin αvβ8-mediated TGF-β activation by DCs in promoting Th17 cell induction in mice.32 and 33 Hence,

RA may act as an important regulator of Th17-mediated pathology in the gut, acting to dampen integrin αvβ8-mediated TGF-β activation–driven Th17 cell induction by CD103+ intestinal DCs during inflammatory responses. It has been proposed that RA can enhance Foxp3+ iTreg induction indirectly by suppressing inflammatory cytokine production by CD4+ CD44hi memory T cells.27 These data would again support a role for RA in enhancing iTreg induction during active immune Resveratrol responses, via inhibition of inflammatory cytokine production by effector/memory T cells.27 However, all iTreg induction experiments described here were performed with naive CD4+, CD44−/low, Foxp3− T cells, with enhanced iTregs still induced by CD103+ intestinal DCs in the absence/presence of RA. We have also performed similar assays, including CD44hi T cells in culture, and again alterations in RA function did not alter the enhanced iTreg induction by CD103+ intestinal DCs (Supplementary Figure 5 and data not shown).

However, capturing a full cell or nucleus can be problematic [21]

However, capturing a full cell or nucleus can be problematic [21]. Solid tumours also shed cells in a patient’s blood stream (circulating tumour cells or CTCs) and cells disseminating to distant organs (disseminated tumour cells or DTCs) (Figure 1). DTCs can remain dormant over a prolonged period of time following resection of the primary tumour, before giving rise to overt metastases [22]. Investigating CTCs and DTCs is important not only for understanding tumour evolution and progression, but also as Venetoclax cell line liquid

biopsies of a solid tumour for guiding diagnosis, prognosis and treatment. Although often just a few CTCs in millilitres of peripheral blood of a cancer patient are present, various isolation techniques based on physical and biological properties of CTCs have been described [23, 24• and 25]. However, a main difficulty remains that unbiased CTC-isolation requires the definition of suitable biomarkers that are expressed in all blood-borne tumour HSP inhibitor drugs cells, but not in normal circulating cells. Similarly, defined physical and biological properties of DTCs, commonly homing to the bone marrow, can be used for their isolation following needle aspiration

through the iliac crest [23 and 24•]. Modern genomics technologies require hundreds of nanograms of input material, while a normal diploid human cell contains about 7 pg of DNA. Hence, whole-genome amplification (WGA) is required to enable analysis of a single cell. WGA of single-cell DNA is based on Multiple Displacement Amplification (MDA), Polymerase Chain Reaction (PCR), or a combination of principles of both displacement amplification and PCR (Figure 2). Importantly, all amplification methods suffer from various imperfections that hamper straightforward

reliable identification of genetic variation. The breadth of genomic coverage, amplification biases (due to local differences in %GC-content or other factors), the prevalence of chimeric DNA molecules, allelic drop outs (ADO), preferential allelic amplifications (PA) and nucleotide copy errors can differ significantly between different WGA approaches. As such, some methods are more apt than others to detect specific genetic variants ADP ribosylation factor [26••, 27••, 28 and 29]. In theory, massively parallel sequencing allows profiling the full spectrum of genetic variation in a cell’s WGA product, from ploidy changes to aneuploidy and (un)balanced structural variants, down to indels and base substitutions. However, the various confounding factors of WGA complicate this process (Figure 3). A one-fit-all WGA method remains to be established, and a comparative analysis of all WGA methods against a benchmark case is acutely needed, assaying the potency of genetic variation detection, including examining the favourable effects of the reduction of reaction volumes and amplification cycles [30••].

This time period was stated by Day and Harris (1978) as the time

This time period was stated by Day and Harris (1978) as the time required for cnidosacs to refill with functional nematocysts. Starved individuals were then immersed for 5–7 s in 3.5% Selleck Dabrafenib KCl. This

treatment caused the gastropods to eject all kleptocnides from their cnidosac without autotomizing their cerata ( Penney et al., 2010). Several minutes after returning to seawater, the animals behaved normally. 60 min after the KCl treatment, the animals were fed with tentacles of Aiptasia spec. The exact time each animal started feeding and ingesting new nematocysts was documented, and analyses of the maturation process of incorporated nematocysts were performed 7, 24, 48, 72 and 96 h respectively after feeding. An additional animal was investigated after 5 days starvation. To document nematocysts maturity states, intact living A. stephanieae individuals were stained with Ageladine A and seawater (1:1000 from

a stock solution of 10 mM in MeOH) for 60–90 min in the dark. After the staining process, each gastropod was anaesthetized in 7% MgCl2 solution for 10 min. This ensured that no kleptocnides were ejected during the preparation of four to five cerata positioned in the anterior body. Single cerata were mounted in seawater on a microscope slide and gently covered by a coverslip, for further analyses under the microscope. Each animal was only used in one interval. The autofluorescence of cnidosacs and adjacent tissue was tested separately in unstained animals under the same excitation PJ34 HCl wavelengths as in stained samples (see below), without detectable fluorescence. MAPK inhibitor The fluorescence of Ageladine A in the nematocysts of the food organism Aiptasia spec. and the kleptocnides of A. stephanieae were monitored by a confocal laser scanning microscope Leica TCS SP2 equipped with a UV laser (coherent). Ageladine A was optically excited using UV light of the wavelength 365 nm. The wavelength between 420 and 500 nm of the emitted light was filtered out and made visible on the screen using the “glow over/under” function of the software. For every mounted cnidosac, as well as for whole mounts of anemones

or gastropods, a z-stack of ten optical sections was taken with identical settings (photomultiplier settings PMT1 = 450 V or PMT1 = 500 V, Pinhole 2, LiA = 2, solution 1024 × 1024 pixel). Sections were analysed individually or as maximum projection pictures. Analyses of Aiptasia were mainly performed with photomultiplier settings of 450 V, whereas those of the gastropods were taken with PMT1 = 500 V. These latter accommodations were chosen after preliminary analyses, since lower voltage resulted in low visibility of the freshly-incorporated nematocysts fluorescence. The fluorescence of the A. stephanieae kleptocnides at different times after incorporation was measured with the “region-of-interest” function of the CLSM software (LCS Lite). The fluorescence intensity was given in imaginary units (i.u.) with values from 0 to 255.

In the presence of oxygen, reactive oxygen species or free radica

In the presence of oxygen, reactive oxygen species or free radicals are produced, causing cell damage by disrupting the cytoplasmic membrane; the increased permeability causes damage to intracellular

targets and reduces the formation of germ tubes. 14, 15, 16 and 17 The main photosensitizers used in antifungal PDT are phenothiazine dyes, phthalocyanines and porphyrins associated with lasers and other non-coherent light sources.12, 18, 19 and 20 Erythrosine has attracted AZD6244 clinical trial interest as a photosensitizer because it is not toxic to the host and has already been approved for use in dentistry.21 Erythrosine is used to detect dental biofilms. This dye has shown potent photodynamic activity and can reduce 3.0–3.7 log10 of Streptococcus mutans biofilm. 21 and 22 Light-emitting diodes (LEDs) have been suggested as alternative light sources to lasers due to their wider emission bands, smaller size, reduced weight and cost, greater flexibility in treatment irradiation time and easy operation.23 and 24 LEDs are used in dentistry as bleaching tools that do not damage oral tissues. LEDs have shown potent activity in PDT and lack of absence of antimicrobial action alone.19, 25 and 26 In PDT against Candida spp., red and blue LEDs were used with phenothiazines (methylene blue PI3K inhibitor and toluidine blue) and Photogem photosensitizers, reducing planktonic cultures by 3.41 log10 and biofilms by less than 1 log10. 19,

25 and 26 However, the effect of erythrosine dye and green LEDs against Candida spp. has not been described. The aim of this study was to evaluate the effect

of PDT mediated by erythrosine dye and green LEDs on planktonic cultures and biofilms of C. albicans and C. dubliniensis. Erythrosine (Aldrich Chemical Co., Milwaukee, WI, USA) was used for the sensitization of yeasts. Erythrosine solution was prepared by dissolving the powdered dye in phosphate-buffered saline (PBS, pH 7.4) and sterilized by filtration through 0.22-μm pore diameter membranes (MFS, Dublin, CA, EUA). After filtration, the dye solution was stored in the dark. The absorption spectrum (400–800 nm) many of the erythrosine solution (1.0 μM in PBS) was verified in a spectrophotometer (Cary 50 Bio, Varian Inc., Palo Alto, CA, USA) coupled to a microcomputer. A green light-emitting diode (LED) (MMOptics, São Carlos, SP, Brazil) was used as the light source with a wavelength of 532 ± 10 nm, an output power of 90 mW, an energy of 16.2 J, a time of 3 min, a fluence rate of 237 mW cm−2 and a fluence of 42.63 J cm−2. The area irradiated in planktonic cultures and biofilms was 0.38 cm2. The temperature at the bottom of the 96-well microtiter plates (Costar Corning, New York, NY, USA) was monitored using an infrared thermometer (MX4, Raytek, Sorocaba, SP, Brazil); no increases in temperature were observed after irradiation with the LED. Reference strains of C. albicans (ATCC 18804) and C.

During the negative phases of the AO and NAO, as in winter 2009–2

During the negative phases of the AO and NAO, as in winter 2009–2010 (NOAA 2010), higher than normal pressure existed over Scandinavia and the surroundings of the BS, and the winter was cold. During the positive phase of the AO, zonal winds are stronger and oceanic Target Selective Inhibitor Library storms follow northerly routes, bringing warmer and wetter weather to Scandinavia and drier conditions to the Mediterranean area. A stronger winter AO indicates a strengthening

of the winter polar vortex from sea level to the lower stratosphere (Thompson & Wallace 1998) and changes in upper-air jet streams, driving factors for weather in the northern hemisphere (Ambaum et al. 2001, Archer & Caldeira 2008). The AO/NAO also affect the latitude of the polar front and cyclone tracks, cyclone intensity (depth and radius), and cyclone number (Simmonds & Keay 2009). The winter (JFM) NAO was positive during the period ABT-263 1987–2007 except in 1996, 2001 and 2005–2006, and negative in 2009–2010, whereas the summer (JJA) NAO has been negative or close to zero since 1998 (NAO 2011). Nitrogen deposition to the BS is highly episodic, a feature that can be detected from measurements (available, e.g. from the EMEP/NILU measurement data base) or using model simulations (Hongisto & Joffre 2005). Dry deposition is also episodic (Hongisto 2003). The changes in large-scale weather systems may affect the frequency of the nitrogen deposition episodes.

This paper examines whether any of the changes in the large-scale circulation Dolutegravir cost can be detected in the forecast meteorological and marine boundary layer (MBL) parameters, most important for nitrogen deposition processes over the Baltic Sea, and whether they have an effect on nitrogen deposition to the Baltic Sea. Numerical time series for trends are investigated

in an attempt to discover the frequency of occurrence of certain peak values in the MBL variables. In addition, the dependence of deposition episodes on regional weather phenomena, such as storm frequency, storm track latitude and variability of precipitation are studied. Variation in nitrogen deposition over the BS is studied using the results of the Hilatar chemistry-transport model (Hongisto 2003), the forecasts of the HIRLAM hydrostatic weather prediction model (High Resolution Limited Area Model, HIRLAM 2002, Undén et al. 2002) and measurements at certain Finnish meteorological stations over the period 1959–2010. HIRLAM has been in operational use at the Finnish Meteorological Institute (FMI) since 1990. The current European model has 60 vertical layers and a horizontal grid of 0.15° resolution; the model covering the Baltic Sea has a finer, 0.068° resolution. The Hilatar chemistry-transport model, a nested dynamic Eulerian model covering Europe and the Baltic Sea area, provides gridded estimates of the fluxes and concentrations of oxidized and reduced nitrogen and sulphur compounds.

ADB Sustainable Development Working Paper # 27 Asian Development

ADB Sustainable Development Working Paper # 27. Asian Development Bank, Manila Philippines. Gurr, G.M., Heong, K.L., Cheng, J.A. and Catindig, J.L.A. 2012. Ecologicval engineering against SGI-1776 mw insect pests in Asian irrigated rice. In Biodiversity and Insect Pests: Key issues for sustainable management. (eds.) Gurr, G.M., Wratten, S.D., Snyder, W.E. and Read, D.M.Y. UK, John Wiley & Sons. pp 214–229. “
“Event Date and Venue Details from * ENTOMOLOGICAL SOCIETY OF AMERICA ANNUAL MEETING,

Portland, OR, USA 16–19 November Contact: ESA, 9301 Annapolis Rd., Lanham, MD 20706-3115, USA Email [email protected]. Fax: 1-301-731-4538. http://www.entsoc.org. 2015 *8th INTERNATIONAL IPM SYMPOSIUM, Salt Lake City, UT, USA 24–26 March Contact: E.E. Wolff. Email [email protected]. *18th INTERNATIONAL PLANT PROTECTION CONGRESS, “Mission Possible: Food for All through Adequate Plant Protection”, Berlin/Dahlem, GERMANY 24–27 August Contact see: http://tinyurl.com/3e96vdr. * ENTOMOLOGICAL SOCIETY OF AMERICA ANNUAL

MEETING, Minneapolis, MN, USA 14–18 November Contact: ESA, 9301 Annapolis Rd., Lanham, MD 20706-3115, USA. [email protected]. Fax: 1-301-731-4538. http://www.entsoc.org. Selleck Anti-diabetic Compound Library Full-size table Table options View in workspace Download as CSV “
“In order to keep food quality and freshness, it is necessary to select correct materials and packaging technologies. In this way, current tendencies include the development of packaging materials that interact with the product. One of the several possibilities, which are being extensively studied, is the incorporation of active substances within the package material, as films based on cassava starch (Kechichian, Ditchifield, Veiga-Santos, & Tadini, 2010). Although many types of new polymers are being industrially produced (PLA, PHA, MycoClean Mycoplasma Removal Kit PCL,

PEA and others), polymers from agricultural sources are the most studied by researchers, especially polysaccharides. Among the films made from polysaccharides, those obtained from starch are the most important because it is one of the most commonly used agricultural raw materials, since it is a renewable source, inexpensive and widely available (Souza, Ditchifield, & Tadini, 2010). Beyond this, it has good film-forming properties. Cassava starch has been extensively used to produce films and the results indicated that these carbohydrates are promising materials in this regard (Bertuzzi et al., 2007, Chen and Lai, 2008, Chillo et al., 2008, Famá et al., 2007, Famá et al., 2006, Kaisangsri et al., 2012, Kechichian et al., 2010, Mali et al., 2006, Müller et al., 2008, Pelissari et al., 2012, Souza et al., 2012, Veiga-Santos et al., 2011, Vercelheze et al., 2012 and Veiga-Santos et al., 2008). Films developed from starch are described as isotropic, odorless, tasteless, colorless, non-toxic and biodegradable (Souza et al., 2010). In a previous study (Souza et al.

2005) Acoustic methods are the most efficient for the mapping an

2005). Acoustic methods are the most efficient for the mapping and monitoring of large benthic areas (Anderson et al. 2008), and a low-cost alternative to direct sampling for mollusc reefs (DeAlteris, 1988, Wildish et al., 1998, Allen et al., 2005, Grizzle et al., 2005, Hutin et al., 2005, Lindenbaum et al., 2008, Snellen et al., 2008, JiangPing et al., 2009 and Raineault et al., 2011). However, no similar method has been developed for infaunal mollusc populations such as razor clams. Atlantic razor clams inhabit intertidal and subtidal sandy bottoms because oxygen can diffuse

though them, which is not the case with muddy bottoms. These solenids can dig down to depths of 60 cm. A habitat preference PD-0332991 in vitro for sandy bottoms with finer granulometry has been observed, although this has been related to larval settlement

(Holme, 1954 and Darriba Couñago and Fernández Tajes, 2011), and thus does not affect their distribution in seeded beds. Furthermore, as razor clams are not sensitive to sand composition or grain shape, their presence has to be detected independently of the different acoustic responses caused by the different types of sediments. The acoustic response from the ocean bottom has two components: scattering from the rough water-sediment interface and volume backscattering. The former is caused by the impedance contrast between sediment and water, whereas the latter originates from sediment grains, shell debris and infaunal species. Both contributions are so mixed that it is difficult to characterise click here the sediment structure using this

information (Diaz et al., 2004 and Anderson et al., 2008). It is generally assumed that for high-frequency echosounders (i.e. f ≥ 100 kHz) the backscattered energy originates mostly in the water-sediment interface Arachidonate 15-lipoxygenase (because of the high attenuation of the compressional waves in the sediment). However, when shell hash is present in the volume, its scattering may dominate above the critical (grazing) angle for frequencies just above 60 kHz ( Lyons 2005). The acoustic signal returning to an echosounder contains not only power but also phase information from the wavefront. Measurement of phase differences at different parts of the transducer allows point-like scatterers to be located: the phase difference is related to the angle formed by the scatterer’s line of sight and the acoustic beam axis. This is actually the principle behind split-beam echosounders (Foote, 1986, Bodholt et al., 1989 and Simmonds and MacLennan, 2005). The first commercial split-beam echosounder was introduced in 1984 and took advantage of new electronic technologies and developments in acoustic signal processing (Foote et al. 1984). The transducer of a split-beam echosounder is usually divided into four quadrants, which allow the measurement of angles in the athwartship and alongship directions.