Coherent Doppler LIDAR with long-duration frequency-modulated pulses for wind sensing.

A coherent Doppler LIDAR (CDL) with long-duration frequency-modulated pulses was demonstrated and validated by analyzing the data observed by a prototype. In traditional CDL using short-duration single-frequency pulses (PCDL; pulsed CDL), there exists a trade-off relationship between distance and velocity resolution. Meanwhile, in earlier work, a theoretical framework of CDL using long-duration frequency-modulated pulses (FMCDL; frequency-modulated CDL) was put forth to eliminate the trade-off. We developed the prototype to be operated as both a PCDL and FMCDL. Analyses of data observed by the PCDL and FMCDL modes showed that the FMCDL worked in good agreement with the PCDL for wind ranging and velocimetry. Furthermore, the performance of the FMCDL in terms of received power and resolution of distance and velocity was quantitatively consistent with ones theoretically expected.

Unveiling the reaction pathways of hydrocarbons via experiments, computations and data science.

Reaction networks of hydrocarbons are explored using first principles calculations, data science, and experiments. Transforming hydrocarbon data into networks reveals the prevalence of the formation and reaction of various molecules. Graph theory is implemented to extract knowledge from the reaction network. In particular, centralities analysis reveals that H+, CCC, CH3+, CC, and [CH2+]C have high degrees and are thus very likely to form or react with other molecules. Additionally, H+, CH3+, C2H5+, C8H15+, C8H17+, and C6H11+ are found to have high control throughout the network and lead towards a series of additional reactions. The constructed network is also validated in experiments while the shortest path analysis is implemented for further comparison between experiment and the network. Thus, combining network analysis with first principles calculations uncovers key points in the development of various hydrocarbons that can be used to improve catalyst design and targeted synthesis of desired hydrocarbons.

[Rapid Screening System for Paralytic Shellfish Toxins in Bivalves by Oligonucleotide Lateral Flow Immunoassay].

The mouse bioassay (MBA) for paralytic shellfish toxins (PSTs) in bivalves has been used as an official method in Japan. It is necessary to develop an alternative method to animal experiments in PSTs assay because 3Rs (Replacement, Reduction, and Refinement) of animal experiments are required from the animal welfare point of view. Various methods such as HPLC-FL, receptor binding assay, LC-MS/MS and ELISA have been established to detect PSTs without performing animal experiments. The present study was undertaken to develop a screening method using oligonucleotide lateral flow immunoassay (OLFIA) for detecting PSTs in bivalves. The screening level was defined as positive at 2 MU/g of MBA that is the half regulation limit of PSTs monitoring in Japan. All 20 positive (equal to or more than 2 MU/g) samples judged from MBA showed a positive reaction in the OLFIA. No positive samples resulted in a false negative reaction. The OLFIA exhibited high accuracy at 2 MU/g of screening criteria. The authors demonstrated here that the OLFIA can be useful for rapid detection of PSTs in bivalves.

Sulfitobacter porphyrae sp. nov., isolated from the red alga Porphyra yezoensis.

Gram-stain-negative, aerobic, halophilic bacteria, designated SCM-1(T), LCM10-1 and CTBL-B-147, were isolated from modified half-strength SWM-III medium, PES medium and thalli after laboratory cultivation of a red alga, Porphyra yezoensis. Phylogenetic analysis of 16S rRNA gene sequences indicated that the new isolates were affiliated to the genus Sulfitobacter of the class Alphaproteobacteria, and the 16S rRNA gene sequence similarity of the new isolates with the closest related species, Sulfitobacter mediterraneus CH-B427(T), was 98.8%. The DNA G+C contents of the new isolates were in the range of 61.4-62.3 mol%. DNA-DNA relatedness values of strain SCM-1(T) with other type strains of the genus Sulfitobacter were less than 15.9%. The new isolates contained Q-10 as the predominant ubiquinone, phosphatidylcholine, phosphatidylglycerol, an unidentified amino lipid and an unidentified lipid as the main polar lipids, and C(18 : 1)ω7c, C(19 : 1)ω7c and C(16 : 0) as the major fatty acids (>10% of the total). Strain SCM-1(T) could be differentiated from Sulfitobacter mediterraneus JCM 21792(T) by 35 morphological and phenotypic characteristics. On the basis of the phylogenetic, genetic and phenotypic properties of the new isolates, the name Sulfitobacter porphyrae sp. nov. is proposed, with strain SCM-1(T) ( = LMG 27110(T) = NBRC 109054(T)) as the type strain.

A case of paralytic shellfish poisoning caused by consumption of visceral balls from geoduck Panopea japonica in Japan.

In the end of March 2018, an unprecedented food poisoning incident due to ingestion of the visceral balls of geoduck Panopea japonica occurred in Japan. The patient, presented with symptoms of numbness on the lips and general weakness, was diagnosed as paralytic shellfish poisoning (PSP). The patient immediately treated with the mechanical ventilation recovered and left the hospital after 3 days treatment. Saxitoxins (STXs) in the plasma and urinary samples collected from the patient on the first and second day after hospitalization were analyzed by ultra high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC/MS/MS) and liquid chromatography with post-column fluorescent detection (LC/FLD). The STXs levels of 499.1 and 6.0 µg/L of STX dihydrochloride equivalent (STX·2HCl eq.) were quantitated by LC/FLD in the urinary samples on the first and second day, respectively. In addition, geoducks harvested from the same areas of the PSP causative specimens after the incident were analyzed by LC/FLD, and the results showed the level of STXs in their whole bodies of the geoducks exceeding 0.8 mg STX·2HCl eq./kg which is the maximum levels of STX in CODEX STAN 292-2008. Prominent toxins in STXs that detected in urinary and geoduck samples and identified by UHPLC/MS/MS and LC/FLD were gonyautoxin-1+4 (GTX1+4). These results concluded that the incident was the food poisoning due to STXs accumulated in the geoducks. This is the first PSP case caused by consumption of geoducks in Japan. This is also the first PSP case that causative toxins are detected in urinary samples of patients involved in PSP in Japan.

New azaspiracid analogues detected as bi-charged ions in Azadinium poporum (Amphidomataceae, Dinophyceae) isolated from Japanese coastal waters.

Lipophilic marine biotoxin azaspiracids (AZAs) are produced by dinoflagellates Azadinium and Amphidoma. Recently, several strains of Azadinium poporum were isolated from Japanese coastal waters, and detailed toxin profiles of two strains (mdd421 and HM536) among them were clarified by several detection techniques on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOFMS). In our present study, AZA analogues in seven strains of A. poporum from Japanese coastal waters (including two previously reported strains) were determined by these detection techniques. The dominant AZA in the seven strains was AZA2 accompanied by small amounts of several known AZAs and twelve new AZA analogues. Eight of the twelve new AZA analogues discovered in our present study were detected as bi-charged ions on the positive mode LC/MS/MS. This is the first report describing AZA analogues detected as bi-charged ions with hexose and sulfate groups in their structures.

Algimonas ampicilliniresistens sp. nov., isolated from the red alga Porphyra yezoensis, and emended description of the genus Algimonas.

Three strains (14A-2-7(T), 14A-3-1 and 14A-3) of Gram-stain-negative, prosthecate, motile bacteria were isolated from an algal medium supplemented with 10 mg ampicillin l(-1) (w/v), in which the red alga Porphyra yezoensis had been cultured. Based on the 16S rRNA gene sequence analysis, the three isolates formed a cluster with the genus Algimonas of the family Hyphomonadaceae. The sequences of the three isolates had high similarity with those of Algimonas porphyrae 0C-2-2(T) (97.6 % similarity) and Litorimonas taeanensis G5(T) (95.6 % similarity). The DNA G+C contents of the three isolates ranged from 54.3 to 55.0 mol%, which were more similar to that of A. porphyrae 0C-2-2(T) (58.5 mol%) than to that of L. taeanensis G5(T) (47.1 mol%). The DNA-DNA relatedness showed that the three isolates were representatives of the same species (88.1-94.0 % relatedness) and that strain 14A-2-7(T) was a representative of a different species from A. porphyrae 0C-2-2(T) and L. taeanensis G5(T) (1.2-8.6 % relatedness). The phenotypic characteristics of strain 14A-2-7(T) differed by 20 results and 30 results from A. porphyrae 0C-2-2(T) and L. taeanensis G5(T), respectively. The three isolates contained ubiquinone-10 as the predominant quinone and C18 : 1ω7c as the major fatty acid. Based on the polyphasic taxonomic analysis, the three isolates represent a novel species of the genus Algimonas, for which the name Algimonas ampicilliniresistens sp. nov. is proposed. The type strain is 14A-2-7(T) ( = LMG 26421(T) = NBRC 108219(T)). An emended description of the genus Algimonas is also proposed.

Algimonas porphyrae gen. nov., sp. nov., a member of the family Hyphomonadaceae, isolated from the red alga Porphyra yezoensis.

Three Gram-negative, stalked, motile bacteria, designated 0C-2-2(T), 0C-17 and LNM-3, were isolated from the red alga Porphyra yezoensis. 16S rRNA gene sequence analysis revealed that the three novel strains belonged to the family Hyphomonadaceae, and were closely related to Litorimonas taeanensis G5(T) (96.5 % 16S rRNA gene sequence similarity) and Hellea balneolensis 26III/A02/215(T) (94.3 %). The DNA G+C contents of the novel isolates (58.5-60.2 mol%) were clearly distinguished from those of L. taeanensis G5(T) (47.1 mol%) and H. balneolensis DSM 19091(T) (47.9 mol%). The G+C content of L. taeanensis G5(T) obtained in this study was quite different from a previous report (63.6 mol%). DNA-DNA hybridization experiments showed that the novel strains constituted a single species. Eleven phenotypic features of the three isolates differed from those of both related genera. The predominant respiratory quinone was ubiquinone-10 and the major fatty acid was C(18 : 1)ω7c. On the basis of this polyphasic taxonomic analysis, the novel strains represent a novel genus and species, for which the name Algimonas porphyrae gen. nov., sp. nov. is proposed. The type strain of Algimonas porphyrae is 0C-2-2(T) (= LMG 26424(T) = NBRC 108216(T)).

Polaribacter porphyrae sp. nov., isolated from the red alga Porphyra yezoensis, and emended descriptions of the genus Polaribacter and two Polaribacter species.

Three Gram-negative, non-motile, strictly aerobic strains, designated LNM-20(T), LCM-1 and LAM-13, were isolated from thalli of the marine red alga Porphyra yezoensis. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolates were associated with the genus Polaribacter in the family Flavobacteriaceae and were most closely related to Polaribacter dokdonensis DSW-5(T) (96.2 % 16S rRNA gene sequence similarity) and Polaribacter gangjinensis K17-16(T) (95.0 %). The DNA G+C content of the isolates was 28.6-29.2 mol%. DNA-DNA hybridization analysis showed that the isolates belonged to a single species distinct from both of their closest relatives. The only isoprenoid quinone detected was menaquinone-6. The main polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. The major fatty acids were iso-C15 : 0, iso-C15 : 1ω10c and iso-C15 : 0 3-OH. The phenotypic features of strain LNM-20(T) differed from those of their closest relatives in several regards (colony colour, growth with 1 % NaCl and on TSA plus 2.5 % NaCl, hydrolysis of Tweens 40 and 80, and oxidization of five carbon compounds). On the basis of phylogenetic, chemotaxonomic and phenotypic analysis, the isolates represent a novel species in the genus Polaribacter, for which the name Polaribacter porphyrae sp. nov. is proposed. The type strain is LNM-20(T) ( = LMG 26671(T)  = NBRC 108759(T)). Emended descriptions of the genus Polaribacter and P. dokdonensis and P. gangjinensis are also proposed.

Azaspiracid accumulation in Japanese coastal bivalves and ascidians fed with Azadinium poporum producing azaspiracid-2 as the dominant toxin component.

The filter-feeding bivalves often accumulate marine toxins by feeding on toxic dinoflagellates that produce marine toxins. Azaspiracids (AZAs) are a group of lipophilic polyether toxins which have been detected in a variety of organisms in many countries. In our present study, accumulation kinetics and toxin distributions in the tissues of seven bivalve species and ascidians relevant to Japanese coastal waters were investigated by experimentally feeding a toxic dinoflagellate Azadinium poporum, which produces azaspiracid-2 (AZA2) as the dominant toxin component. All bivalve species and ascidians investigated in this study had the capability to accumulate AZA2 and no metabolites of AZA2 were detected in the bivalves and the ascidians. Japanese short-neck clams, Japanese oysters, Pacific oysters and ascidians accumulated AZA2 with the highest concentrations on the hepatopancreas, whereas the highest concentrations of AZA2 were found on the gills in surf clams and horse clams. Hard clams and cockles accumulated high levels of AZA2 in both the hepatopancreas and the gills. As far as we know, this is the first report describing detailed tissue distribution of AZAs in several bivalve species other than mussels (M. edulis) and scallops (P. maximus). Variation of accumulation rates of AZA2 in Japanese short-neck clams on different cell densities or temperatures were observed.

Maritalea porphyrae sp. nov., isolated from a red alga (Porphyra yezoensis), and transfer of Zhangella mobilis to Maritalea mobilis comb. nov.

Three Gram-negative, motile, aerobic bacteria were isolated from cultures of the marine red alga Porphyra yezoensis. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the novel strains were closely related to Maritalea myrionectae CL-SK30(T) (97.9% 16S rRNA gene sequence similarity) and Zhangella mobilis E6(T) (96.2 %). 16S rRNA gene sequence similarity between Z. mobilis E6(T) and M. myrionectae CL-SK30(T) was 97.9%. The DNA G+C contents of the isolates (49.4-50.0 mol%) were similar to those of M. myrionectae DSM 19524(T) (52.3 mol%) and Z. mobilis JCM 15144(T) (50.3 mol%). From these results, it was difficult to differentiate the genus Zhangella from the genus Maritalea. DNA-DNA hybridization demonstrated that the isolates belonged to a single species. The isolates could also be distinguished from M. myrionectae and Z. mobilis on the basis of chemotaxonomic and phenotypic features, including fatty acid composition (particularly C(16:1)ω7c), growth with 6-9% (w/v) NaCl, carbon utilization, oxidation patterns and so on. A novel species of the genus Maritalea is proposed to accommodate the three isolates, with the name Maritalea porphyrae sp. nov. The type strain is LCM-3(T) (=LMG 25872(T)=NBRC 107169(T)). Furthermore, it is proposed that Zhangella mobilis should be transferred from the genus Zhangella to the genus Maritalea, with the name Maritalea mobilis comb. nov. (type strain E6(T)=CGMCC 1.7002(T)=JCM 15144(T)).

Sequential extraction of inorganic arsenic compounds and methyl arsenate in human urine using mixed-mode monolithic silica spin column coupled with gas chromatography-mass spectrometry.

A sequential analytical method was developed for the detection of arsenite, arsenate, and methylarsenate in human urine by gas chromatography-mass spectrometry (GC-MS). The combination of a derivatization of trivalent arsenic compounds by 2,3-dithio-1-propanol (British antilewisite; BAL) and a reduction of pentavalent arsenic compounds (arsenate and methylarsenate) were accomplished to carry out the analysis of arsenic compounds in urine. The arsenic derivatives obtained using BAL were extracted in a stepwise manner using a monolithic spin column and analyzed by GC-MS. A linear curve was observed for concentrations of arsenic compounds of 2.0 to 200 ng/mL, where the correlation coefficients of calibration curves were greater than 0.996 (for a signal-to-noise (S/N) ratio >10). The detection limits were 1 ng/mL (S/N > 3). Recoveries of the targets in urine were in the range 91.9-106.5%, and RSDs of the intra- and interday assay for urine samples containing 5, 50, and 150 ng/mL of arsenic compounds varied between 2.95 and 13.4%. The results from real samples obtained from a patient suspected of having ingested As containing medications using this proposed method were in good agreement with those obtained using high-performance liquid chromatography with inductively coupled plasma mass spectrometry.

Assessing the ADC of Bone-marrow on Whole-body MR Images in Relation to the Fat-suppression Method and Fat Content.

PURPOSE: To compare apparent diffusion coefficients (ADCs) of bone marrow on diffusion-weighted imaging (DWI) between two fat-suppression techniques, and to evaluate the association between bone-marrow ADCs and the proton density fat fraction (PDFF). METHODS: Seventy-seven patients underwent whole-body DWI with short-inversion time inversion-recovery (STIR) (DWISTIR) and/or STIR + selective water-excitation (spectral-spatial RF [SSRF]) (DWISTIR+SSRF). ADCs of lumbar vertebrae (L3 and L4) were compared between DWISTIR and DWISTIR+SSRF, and correlated with the PDFF. RESULTS: Lumbar ADCs obtained by DWISTIR and DWISTIR+SSRF were significantly correlated (L3: r = 0.90, P < 0.0001, L4: r = 0.90, P < 0.0001). Lumbar ADCs (× 10-6 mm2/s) obtained by DWISTIR were significantly lower than those by DWISTIR+SSRF (L3: 479 ± 137 and 490 ± 148, P < 0.05, L4: 456 ± 114 and 471 ± 118, P < 0.005). Residual fat signals were more clearly observed on DWISTIR than on DWISTIR+SSRF. The ADCs of L3 obtained by DWISTIR and DWISTIR+SSRF exhibited significant positive correlations with the PDFF (r = 0.51, P < 0.0001, and r = 0.45, P < 0.0001, respectively), and the ADCs of L4 obtained by DWISTIR and DWISTIR+SSRF exhibited significantly positive correlations with the PDFF (r = 0.40, P < 0.0005, and r = 0.40, P < 0.0005, respectively). CONCLUSION: Irrespective of different fat-suppression methods, lumbar ADCs were positively correlated with the PDFF, being inconsistent with previous studies. Lumbar ADCs obtained by DWISTIR were significantly lower than those obtained by DWISTIR+SSRF, probably due to residual fat signals on DWISTIR. However, this difference (< 4%) did not explain the positive correlation between lumbar ADC and PDFF.

Simultaneous extraction of acidic and basic drugs from urine using mixed-mode monolithic silica spin column bonded with octadecyl and cation-exchange group.

A method coupling spin column extraction with gas chromatography-mass spectrometry was developed for the simultaneous extraction of acidic and basic drugs from urine. Benzodiazepines, local anaesthetics, antidepressants, and barbiturates were used as model drugs. Sample loading, washing, and elution of the target drugs were accomplished by centrifugation of the column. In this study, mixed-mode monolithic silica bonded with a C18 reversed-phase and a strong cation exchange phase was packed in a spin column. The pH of a urine sample (0.2 mL) was adjusted to 3 and the analytes adsorbed onto the column were eluted with 0.1 mL of MeOH containing 2% NH3; all the tested drugs were simultaneously extracted from urine. The recovery of the tested drugs was 65-123%. Up to a concentration of 2500 ng/mL of the target drugs in urine, a linear curve was observed (r(2)>0.996). The intra- and interday RSDs at three different concentrations in urine were 2.1-14.7%. For RSDs lower than 15%, the limits of detection were 1-25 ng/mL. The proposed method was successfully applied for clinical and forensic cases and the results thus obtained were in good agreement with those obtained by conventional methods.

Development of an absolute quantification method for ribosomal RNA gene copy numbers per eukaryotic single cell by digital PCR.

Recent increase of Harmful Algal Blooms (HAB) causes world-wide ecological, economical, and health issues, and more attention is paid to frequent coastal monitoring for the early detection of HAB species to prevent or reduce such impacts. Use of molecular tools in addition to traditional microscopy-based observation has become one of the promising methodologies for coastal monitoring. However, as ribosomal RNA (rRNA) genes are commonly targeted in molecular studies, variability in the rRNA gene copy number within and between species must be considered to provide quantitative information in quantitative PCR (qPCR), digital PCR (dPCR), and metabarcoding analyses. Currently, this information is only available for a limited number of species. The present study utilized a dPCR technology to quantify copy numbers of rRNA genes per single cell in 16 phytoplankton species, the majority of which are toxin-producers, using a newly developed universal primer set accompanied by a labeled probe with a fluorophore and a double-quencher. In silico PCR using the newly developed primers allowed the detection of taxa from 8 supergroups, demonstrating universality and broad coverage of the primer set. Chelex buffer was found to be suitable for DNA extraction to obtain DNA fragments with suitable size to avoid underestimation of the copy numbers. The study successfully demonstrated the first comparison of absolute quantification of 18S rRNA copy numbers per cell from 16 phytoplankton species by the dPCR technology.

Determination of optimal culture conditions for toxin production by a Prorocentrum lima complex strain with high diarrhetic shellfish toxins yield.

Diarrhetic shellfish poisoning (DSP) is caused by the consumption of shellfish contaminated by diarrhetic shellfish toxins (DSTs) such as okadaic acid (OA) and dinophysistoxins (DTXs) produced by some species of dinoflagellates. To prevent the occurrence of human intoxication cases, inspection of DSTs (OA and DTXs) in shellfish is important. An instrumental method using liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been recently employed in Japan for the monitoring of OA and DTXs in shellfish. For such analysis, reference materials (RMs) of OA and DTXs are essential. Demand for the reference materials, especially dinophysistoxin-1 (DTX1), is recently increasing in Japan. Production of the materials has been performed by mass cultivation of a dinoflagellate (Prorocentrum lima) strain that produces DTXs and OA, which indicates that the efficiency of production depends on the toxin production of the strain used. In this study, P. lima complex subclade 1e strain MIO12P was determined to be a high DTX1 producer among the three Japanese strains of the P. lima complex (subclades 1e, 1f, and 1i). It was clarified that the culture medium suitable for toxin production by strain MIO12P was metals mix SWII medium, and the optimal temperature and salinity for toxin production were 25 °C and salinity 30, respectively. The DTX1 yield (1265.3 ng ml-1) of strain MIO12P cultured under the conditions described above was the highest reported worldwide. Prorocentrum lima complex subclade 1e strain MIO12P is expected to be useful for the sustainable production of DTX1 as a source of RMs for chemical and biochemical methods in the future.

Complex profiles of azaspiracid analogues in two culture strains of Azadinium poporum (Amphidomataceae, Dinophyceae) isolated from Japanese coastal waters determined by LC-MS/MS.

Lipophilic marine biotoxins azaspiracids (AZAs) are produced by dinoflagellates Azadinium and Amphidoma. Recently, several strains of Azadinium poporum were isolated from Japanese coastal waters. In our present study, AZA analogues in two strains (mdd421 and HM536) of A. poporum were analyzed by several detection techniques on the liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOFMS). The dominant AZA analogue in the Japanese A. poporum strains was AZA2. Other known AZA analogues were AZA11, AZA35, AZA2 methyl ester and AZA2 phosphate ester. Besides these AZAs, thirteen new AZA analogues were discovered in the two strains. A putative AZA analogue (Compound 1) with the smallest molecular weight ever found in nature was also discovered in the two strains. This is the first report describing detailed AZA profiles in Japanese isolates of A. poporum.

SxtA localizes to chloroplasts and changes to its 3'UTR may reduce toxin biosynthesis in non-toxic Alexandrium catenella (Group I)✰.

SxtA is the enzyme that catalyses the first step of saxitoxin biosynthesis. We developed an immunofluorescent method to detect SxtA using antibodies against SxtA peptides. Confocal microscopy revealed the presence of abundant, sub-cellularly localized signal in cells of toxic species and its absence in non-toxic species. Co-localization of SxtA with Rubisco II and ultra-structural observation by transmission electron microscopy strongly suggested the association of SxtA with chloroplasts. We also characterized a non-toxic sub-clone of Alexandrium catenella (Group I) to elucidate the mutation responsible for its loss of toxicity. Although sxtA4 gene copy number was indistinguishable in toxic and non-toxic sub-clones, mRNA and protein expression were significantly reduced in the non-toxic sub-clone and we uncovered sequence variation at the 3' untranslated region (3'UTR) of sxtA4 mRNA. We propose that differences in the sxtA4 mRNA 3'UTR lead to down-regulation of STX biosynthesis post-transcriptionally, thereby explaining the differences in toxicity amongst different A. catenella (Group I) sub-clones.

Zero Echo Time-Based PET/MRI Attenuation Correction in Patients With Oral Cavity Cancer: Initial Experience.

PURPOSE: The aims of this study were to demonstrate the feasibility of zero echo time (ZTE) MRI for jawbone identification, and to evaluate the quantitative performance of F-FDG PET/MRI with ZTE-based attenuation correction (ZTE-AC) compared with PET/CT and PET/MRI with Dixon MR-based AC (Dixon-AC) in patients with oral cavity cancer (OCC). MATERIALS AND METHODS: Thirteen OCC patients underwent whole-body F-FDG PET/CT and subsequent regional PET/MRI with Dixon-AC and ZTE-AC in 1 day. SUVs of the primary OCC and metastatic cervical lymph nodes (CLNs) were measured on PET/CT (SUVCT), PET/MRI with Dixon-AC (SUVDixon), and ZTE-AC (SUVZTE). The SUVs were then compared. RESULTS: The ZTE MRI scans minimized the effects of metal artifacts from dentures, and ZTE-AC maps correctly delineated the jawbones. SUVDixon and SUVZTE had significant positive correlations with SUVCT (Pearson r = 0.97 and r = 0.99 for OCC, and r = 0.98 and r = 0.98 for CLNs, respectively). The mean ± SD of SUVCT, SUVDixon, and SUVZTE were 14.4 ± 8.0, 14.5 ± 8.6, and 15.6 ± 8.8 for OCC, and 6.3 ± 3.0, 8.0 ± 4.0, and 7.6 ± 3.9 for CLNs, respectively. For OCCs, SUVZTE was significantly higher than SUVCT (P < 0.05), whereas there was no significant difference between SUVCT and SUVDixon or between SUVDixon and SUVZTE. For CLNs, SUVDixon and SUVZTE were significantly higher than SUVCT (P < 0.01 and P < 0.05, respectively), and SUVDixon was significantly higher than SUVZTE (P < 0.01). CONCLUSIONS: ZTE MRI can correctly identify jawbones while minimizing the effects of metal artifacts. The ZTE-AC method in F-FDG PET/MRI reduces the underestimation of tracer uptake due to Dixon-AC jawbone errors and improves the quantitative performance of PET for OCC patients.

Heptavalinamide A, an Extensively N-Methylated Linear Nonapeptide from a Cyanobacterium Symploca sp. and Development of a Highly Sensitive Analysis of N,N-Dimethylvaline by LCMS.

An extensively N-methylated linear nonapeptide heptavalinamide A (1) was isolated from the marine cyanobacterium Symploca sp. collected at Kabira Reef of Ishigaki Island, Okinawa. The amino acid sequence of 1 was assigned by interpretation of 2D NMR and MS/MS data. The absolute configurations of the constituent amino acids were determined by the application of Marfey's method. A method to assign the configuration of N,N-dimethylvaline by LCMS is discussed.