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Artificial molecular machines, especially when based on wheel-and-axle complexes, can generate mechanical motions in response to external stimuli. Ferrocene (Fc) is a key component, but it decomposes at 300 K on metal surfaces. Here, a novel method is presented to construct and control the molecular complex composed of ammonium-linked ferrocene (Fc-amm) and tetrabrominated crown ether (BrCR) on a Cu(111) surface. Fc-amm molecules are periodically arranged on a BrCR monolayer film and imaged using scanning tunneling microscopy and spectroscopy. A lateral motion of the Fc groups by ≈0.1 nm is observed for pairs of "edge-on" Fc-amm molecules upon hole injection. This sliding motion is reversible and controlled by the applied voltage. Theoretical analysis indicates that the motion is caused by increased Coulomb repulsion of the hole-doped Fc-amm+ ions and accompanied by a weakening of CH-π interactions. These findings open new avenues for developing nanomolecular devices using on-surface bottom-up processes., (© 2024 Wiley‐VCH GmbH.)

Chemical synthesis typically yields the most thermodynamically stable ordered arrangement, a principle also governing surface synthesis on an atomically level two-dimensional (2D) surface, fostering the creation of structured 2D formations. The linear connection arising from energetically stable chemical bonding precludes the generation of a 2D random network comprised of one-dimensional (1D) convoluted stripes through on-surface synthesis. Nonetheless, we underscored that on-surface synthesis possesses the capability not solely to fashion a 2D ordered linear network but also to fabricate a winding 2D network employing a precursor with a soft ring and intermediate state bonding within the Ullmann reaction. Here, on-surface synthesis was exhibited on Cu(111) employing a 2D self-assembled monolayer array of 4,4',5,5'-tetrabromodibenzo[18]crown-6 ether (BrCR) precursors. These precursors were purposefully structured, with a crown ether ring at the core and Br atoms positioned at the head and tail ends, facilitating preferential connections along the elongated axis to foster a 1D stripe configuration. We illustrate how adjustments in the quantities of the intermediate state, serving as a primary linkage, can yield a labyrinthine, convoluted winding 2D network of stripes. The progression of growth, underlying mechanisms, and electronic structures were scrutinized using an ultrahigh vacuum low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) setup combined with density functional theory (DFT) calculations. This experimental evidence opens a novel functionality in leveraging on-surface synthesis for the formation of a 2D random network. This discovery holds promise as a pioneering constituent in the construction of a ring host supramolecule, augmenting its capability to ensnare guest atoms, molecules, or ions.

In the western North Pacific, prominent granulomatous testes have been detected in many Brucella-infected common minke whales (Balaenoptera acutorostrata), but there have been no reports in toothed cetaceans. We found severe orchitis with granulomatous lesions in a rough-toothed dolphin (Steno bredanensis) stranded on the Pacific coast of Japan in 2011. Histopathological examination revealed leukocyte infiltration of the lesions. DNA from the lesion was analyzed by PCR and it showed molecular biological similarities with those of Brucella-infected common minke whales and Brucella ceti of sequence-type 27 (ST27). These results suggest that the type of Brucella ceti that infected the dolphin was ST27, which may have caused severe orchitis. This study adds to our understanding of Brucella infections in marine mammals.

Most intrinsic muscles of the forelimb in dolphins are either degenerated or lost; however, the muscles around the shoulder joint are well preserved. We dissected the forelimbs of Pacific white-sided dolphins and constructed a full-scale model of the flipper to compare and examine their movements following dissection. The humerus was oriented at approximately 45° ventrally from the horizontal plane of the dolphin and 45° caudally from the frontal plane. This maintains the neutral position of the flipper. The deltoideus and pectoralis major muscles were inserted into the body of the humerus, and the flipper was moved in the dorsal and ventral directions, respectively. A large tubercle, known as the common tubercle, was observed at the medial end of the humerus. Four muscles were inserted into the common tubercle: the brachiocephalicus, supraspinatus, and cranial part of the subscapularis, which laterally rotated the common tubercle. Subsequently, the flipper swung forward, and its radial edge was lifted. Conversely, the medial rotation of the common tubercle caused by the coracobrachialis and the caudal part of the subscapularis was accompanied by backward swinging of the flipper and lowering of the radial edge. These findings suggest the function of the flipper as a stabilizer or rudder is caused by the rotation of the humerus's common tubercle., (© 2023 American Association for Anatomy.)

Superconductors are of type I or II depending on whether they form an Abrikosov vortex lattice. Although bulk lead (Pb) is classified as a prototypical type-I superconductor, we show that its two-band superconductivity allows for single-flux-quantum and multiple-flux-quanta vortices in the intermediate state at millikelvin temperature. Using scanning tunneling microscopy, the winding number of individual vortices is determined from the real space wave function of its Caroli-de Gennes-Matricon bound states. This generalizes the topological index theorem put forward by Volovik for isotropic electronic states to realistic electronic structures. In addition, the bound states due to the two superconducting bands of Pb can be separately detected and the two gaps close independently inside vortices. This yields strong evidence for a low interband coupling.

The diets of pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales in Japanese waters are poorly known. We report new information on the diets of these two species from these waters based on identifiable hard-part remains recovered from the stomach contents of 29 whales (11 pygmy and 18 dwarf sperm whales) that stranded between 1991 and 2021; those of a further two dwarf sperm whales were empty. The cephalopod (and secondarily fish and crustacean) component of the diets of these 29 whales, based on analysis of identifiable stomach-content remains, is described. The main prey includes cephalopods, represented by 1556 identifiable lower beaks (and 1483 upper beaks), crustaceans (represented by heavily digested, unidentifiable remains), and fishes (as represented by 92 otoliths). Identified prey comprises 30 species from 16 cephalopod families and 5 families from 5 fish orders. Oceanic cephalopods are the main prey of both whale species, particularly Enoploteuthis (Paraenoploteuthis) chunii and Chiroteuthis (Chirothauma) picteti. Prey diversity index values (Shannon-Weaver's diversity index H') are 2.41 for the pygmy sperm whale and 2.66 for the dwarf sperm whale. Although the main cephalopod component in the diets of these two whale species is similar, Pianka's index (0.40), a measure of niche overlap, is not that high, and may be influenced by differences in prey dominance in different feeding areas., (Copyright © 2023. Published by Elsevier Ltd.)

The two Kogia species, the pygmy sperm whale (K. breviceps) and the dwarf sperm whale (K. sima), have similar morphological and biological features as well as diets. Both species are deep divers, and both have wide distributions from tropical to warm-temperate zones. Although K. breviceps is larger than K. sima, there are few reports of habitat differentiation between the two species. The distribution of K. breviceps is concentrated in higher-latitudes, and this species dives deeper than K. sima. We investigated whether these two species differ in their population structures in the western North Pacific. Using stranded specimens from Japan, we compared the population genetic patterns of the two Kogia species using mtDNA control region variation (941 bp). In total, 34 K. breviceps samples and 54 K. sima samples from stranded individuals around Japan were successfully sequenced. Thirty haplotypes were detected in K. breviceps and 34 in K. sima, indicating high genetic diversity for both. Almost all these haplotypes are unique to the western North Pacific, but did not constitute distinct phylogeographic clades within either species. We detected differences between the species in the shape of haplotype networks and in the potential time of population expansion, indicating that the western North Pacific population of the two biologically similar species could have different population demographies. This may reflect differences in evolutionary histories and in the details of their ecological niches., (Copyright © 2023. Published by Elsevier Ltd.)

In this work we fabricate and characterize a functionalized superconducting (SC) Nb tip of a scanning tunnelling microscope (STM). The tip is functionalized with a Tetracyanoquinodimethane molecule (TCNQ) that accepts charge from the tip and develops a magnetic moment. As a consequence, in scanning tunnelling spectroscopy (STS), sharp, bias symmetric sub-gap states identified as Yu-Shiba-Rusinov (YSR) bound states appear against the featureless density of states of a metallic graphene on Ir(111) sample. Although the coupling regime of the magnetic impurity with the SC tip depends on the initial absorption configuration of the molecule, the interaction strength between the SC tip and the charged TCNQ molecule can be reversibly controlled by tuning the tip-sample distance. The controlled transition from one coupling regime to the other allows us to verify the relation between the energy scales of the two competing many-body effects for the functionalized tip. Quenching the SC state of the Nb tip with a magnetic field switches abruptly from a tip dominated by the YSR bound states to a Kondo tip.

Whales accumulate high levels of environmental pollutants. Exposure to polychlorinated biphenyls (PCBs) and their metabolites (OH-PCBs) could be linked to abnormal behavior, which may lead to mass stranding of marine mammals. Whales may thus suffer from adverse effects such as neuronal dysfunction, yet testing the neurotoxicity of these compounds has never been feasible for these species. This study established neurons chemically reprogrammed from fibroblasts of mass stranded melon-headed whales ( Peponocephala electra ) and used them for in vitro neurotoxicity assays. Exposure to 4-hydroxy-2',3,5,5'-tetrachlorobiphenyl (4'OH-CB72), a metabolite of PCBs, caused apoptosis in the reprogrammed neurons. Transcriptome analysis of 4'OH-CB72-treated whale neurons showed altered expressions of genes associated with oxidative phosphorylation, chromatin degradation, axonal transport, and neurodegenerative diseases. These results suggest that 4'OH-CB72 exposure may induce neurodegeneration through disrupted apoptotic processes. A comparison of the results with human reprogrammed neurons revealed the specific effects on the whale neurons. Our noninvasive approach using fibroblast-derived neurons is useful for hazard and risk assessments of neurotoxicity in whales.

The present study determined recent accumulation levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), polychlorinated diphenyl ethers (PCDEs), methoxylated-PBDEs (MeO-PBDEs) and 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1) in the blubber of melon-headed whales (Peponocephala electra) stranded along the Japanese coastal waters in 2015 and examined temporal trends of these organohalogen compound (OHC) levels by analyzing blubber samples of this species archived in the environmental specimen bank which were collected in 1982, 2001, 2002, 2006, 2010 and 2011. The median concentrations in melon-headed whales stranded recently were in the order of DDTs ≈ PCBs > HBCDDs > Q1 > CHLs > MeO-PBDEs > PBDEs > HCB > HCHs > PCDEs, indicating that considerable amounts of HBCDDs, in addition to DDTs and PCBs, have been transported to tropical and subtropical waters of the open ocean and pelagic whale species might be exposed to relatively high levels of these OHCs. Temporal trend analyses of OHC levels in the blubber of melon-headed whales revealed significant decrease for anthropogenic OCs such as DDTs, PCBs, HCB, HCHs and PCDEs, and significant increase for CHLs, PBDEs, HBCDDs, MeO-PBDEs and Q1 since 1982. Besides, the analyses from 2001 to 2015 showed no decreasing trends (unchanged) for some PCB congeners, p,p'-DDE, cis- and trans-nonachlors, Q1, BDE-47, -100 and -154, and significantly increasing trends for α-HBCDD and 6MeO-BDE47, suggesting their chronic exposure for this pelagic whale species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

We describe a case of systemic toxoplasmosis in a female adult narrow-ridged finless porpoise (Neophocaena asiaeorientalis) found in May 2018 inside a gillnet set in the Ariake Sound, southern Japan. The main lesions observed were lymphoplasmacytic and focally necrotizing encephalitis, necrotizing to granulomatous adrenalitis, myocarditis, and inflammation in the intestinal wall, associated with protozoal tissue cysts and tachyzoites. Additionally, the individual had a 5.6 mm (crown-rump length) early-stage embryo in the left uterine horn, which had multifocal necrotizing lesions with intralesional tissue cysts and tachyzoites in the parenchyma. Immunohistochemistry and PCR and sequencing of the internal transcribed spacer 1 region confirmed a Toxoplasma gondii infection. Further genotyping revealed an atypical type II genotype with a type I pattern for the Apico locus. Narrow-ridged finless porpoises are an endangered coastal species already facing various anthropogenic threats. Toxoplasmosis, especially with its ability to transmit to an early-stage embryo, should be considered an emerging threat to this vulnerable species., (© Wildlife Disease Association 2021.)

Ambergris, a sperm whale metabolite, has long been used as a fragrance and traditional medication, but it is now rarely available. The odor components of ambergris result from the photooxidative degradation of the major component, ambrein. The pharmacological activities of ambergris have also been attributed to ambrein. However, efficient production of ambrein and odor compounds has not been achieved. Here, we constructed a system for the synthesis of ambrein and odor components. First, we created a new triterpene synthase, "ambrein synthase," for mass production of ambrein by redesigning a bacterial enzyme. The ambrein yields were approximately 20 times greater than those reported previously. Next, an efficient photooxidative conversion system from ambrein to a range of volatiles of ambergris was established. The yield of volatiles was 8-15%. Finally, two biological activities, promotion of osteoclast differentiation and prevention of amyloid β-induced apoptosis, were discovered using the synthesized ambrein.

The preparation of cetacean, in particular baleen whale, skeletons presents a great challenge due to their high lipid content and uncommon size. Documentation of the skeletal morphology is important to produce accurate and reliable models for both research and educational purposes. In this paper, we used a 10.8-meter long Omura's whale stranded in Hong Kong waters in 2014 as an example for the illustration. This rare and enormous specimen was defleshed, macerated, and sun-dried to yield the skeleton for research and public display. Morphology of each bone was then documented by photogrammetry. The complex contour of the skeleton made automated photoshoot inadequate and 3 manual methods were used on bones of different sizes and shapes. The captured photos were processed to generate three-dimensional (3D) models of 166 individual bones. The skeleton was printed half-size with polylactic acid for display purposes, which was easier to maintain than the actual cetacean bones with high residual fat content. The printed bones reflected most anatomical features of the specimen, including the bowing out rostral region and the caudal condylar facet that articulated with Ce1, yet the foramina on the parieto-squamosal suture, which are diagnostic character of Balaenoptera omurai, and an indented groove on the frontal bone at the posterior end of the lateral edge were not clearly presented. Extra photoshoots or 3D surface scanning should be performed on areas with meticulous details to improve precision of the models. The electronic files of the 3D skeleton were published online to reach a global audience and facilitate scientific collaboration among researchers worldwide.

Stejneger's beaked whales ( Mesoplodon stejnegeri ) are one of the lesser known species of mammals, with little information available on their population status or incidence of diseases. Recent pathologic investigations on stranded and bycaught wild cetaceans around Hokkaido, Japan, revealed an unusually high incidence of systemic amyloidosis in this species, warranting further investigation. The objective of this study was to further characterize the systemic amyloidosis of Stejneger's beaked whales by retrospective histopathologic analyses of tissues from animals that stranded in Japan between 1994 and 2018. Various tissues from 35 individuals were examined histologically with hematoxylin and eosin, Congo red, and immunohistochemistry for amyloid A (AA), in which 12 (34%) were diagnosed with systemic amyloidosis. The organs with the highest severity of amyloid deposition were the stomach and intestine. The type of amyloid was confirmed as AA of approximately 9 kDa by 2-dimensional gel electrophoresis with extracted amyloid from the liver and subsequent Western blotting with an antiserum against AA peptide. There were no statistically significant associations between amyloidosis and sex, body condition of the whales, or the presence of chronic inflammation. The high prevalence of this disease might be of concern for overall population numbers, and continued pathologic monitoring of stranded animals is necessary throughout its distributional range.

We report an ultra-high-vacuum low-temperature (4.6 K) scanning tunneling microscopy study of the molecular structure and dynamics of a carbon monoxide (CO) monolayer adsorbed at 20 K on Cu(111). We observe the well-known 1.4 × 1.4 phase of CO/Cu(111) for the first time in real-space imaging. At 4.6 K, the hexagonal symmetry of the monolayer is locally broken by the formation of stripes made of single and double CO rows of different apparent heights. Using density functional theory calculations, we assign the high rows to CO molecules adsorbed mostly at off-center top sites and the low rows to bridge sites. Groups of three or four very high molecules appear randomly and are assigned to nearest-neighbor, titled top site molecules. We observe simultaneous hopping of a few CO molecules between adjacent top and bridge sites, which produces the apparent motion of the stripe pattern.

A serologic investigation of Brucella infection was performed in 7 species of cetaceans inhabiting along the coast of Japan. A total of 32 serum samples were examined by enzyme-linked immunosorbent assay (ELISA) using Brucella abortus and B. canis antigens. One serum sample from five melon-headed whales (Peponocephala electra) was positive for B. abortus. No serum sample showed positive for B. canis. The ELISA-positive melon-headed whale serum demonstrated a strong band appearance only against B. abortus antigens in Western blot analysis. Many detected bands were discrete, while some of them had a smeared appearance. The present results indicate that Brucella infection occurred in melon-headed whale population and the bacterial antigenicity is more similar to that of B. abortus than B. canis.

Two types of Berardius are recognised by local whalers in Hokkaido, Japan. The first is the ordinary Baird's beaked whale, B. bairdii, whereas the other is much smaller and entirely black. Previous molecular phylogenetic analyses revealed that the black type is one recognisable taxonomic unit within the Berardius clade but is distinct from the two known Berardius species. To determine the characteristics of the black type, we summarised external morphology and skull osteometric data obtained from four individuals, which included three individuals from Hokkaido and one additional individual from the United States National Museum of Natural History collection. The whales differed from all of their congeners by having the following unique characters: a substantially smaller body size of physically mature individuals, proportionately shorter beak, and darker body colour. Thus, we conclude that the whales are a third Berardius species.

A tungsten (W) tip has been used as a standard tip probe because of its robustness at the highest boiling temperature; the use cases include a field emission (FE) electron source for scanning electron microscopy (SEM) and a scanning probe microscopy tip. The W tip probe has generally been fabricated through a chemical etching process with aqueous solutions. In this study, we propose a new method-flame etching. Without using aqueous solutions, a W tip probe was successfully fabricated within 3 s in air, which is very fast and convenient, and beneficial for mass production (additionally, no expensive setup is necessary). A W tip probe was obtained simply by putting a W wire into an oxygen-liquefied petroleum (O 2 +LP) gas flame (giving the highest temperature of ∼2300 K) through a microtorch for a few seconds. The obtained W tip provided atomically resolved scanning tunneling microscopic images. Also, since FE electrons were detected by applying ∼10 6 V/m, the tip can be used as an FE-SEM source. Generation and vaporization of WO 3 on the W surface are important processes to form a tip shape.

Understanding the interactions between a tip apex and a target atom or molecule is crucial for the manipulation of individual molecules with precise control by using scanning tunnelling microscopy (STM) and atomic force microscopy. Herein, we demonstrate the manipulation of target CO molecules on a Cu(111) substrate using a CO-functionalized W tip with atomic-scale accuracy. All experiments were performed in a home-built ultra-high vacuum STM system at 5 K. The CO-tip was fabricated by picking up a single CO molecule from a Cu(111) surface. In contrast to a metal tip, repulsive interactions occur between the CO-tip and the target CO molecule. This repulsive interaction promises perfect lateral hopping without any vertical hopping. Hopping events were directly monitored as sudden current drops in the simultaneously measured I-z curves. A larger barrier height between the CO-tip and the target CO (∼9.5 eV) was found from the slope of the I-z curve, which decreases the electron tunnelling probability between the tip and sample. Therefore, electron-driven manipulation cannot be a major trigger for the CO-CO repulsive manipulation. The CO-tip is able to manipulate only the target CO molecule, even when another CO molecule was located ∼0.5 nm away. Statistical measurements revealed that the nearest neighbour atop site is the energetically stable position after hopping. However, if the CO target has another CO molecule in a neighbouring position (denoted as a 'pair'), the target CO hops more than twice as far. This means that the CO-tip experiences a larger repulsive interaction from the pair. These observations of CO-tip manipulation are useful for the design of two-dimensional artificial molecular networks as well as for developing a better understanding of catalytic oxidation processes.

Precise control of organic molecule deposition on a substrate is quite important for fabricating single-molecule-based devices. In this study, we demonstrate whether a quartz-crystal microbalance (QCM) widely used for a film growth calibration has the ability to precisely measure the number of organic molecules adsorbed on a substrate. The well-known Sauerbrey's equation is extended to formulate the relation between QCM resonant frequency shift and the number of adsorbed molecules onto the QCM surface. The formula is examined by QCM measurements of sublimation of π-conjugated organic molecules and direct counting of the deposited molecules one by one onto metal substrates, using ultrahigh vacuum low-temperature scanning tunneling microscopy (STM). It is revealed that the number of adsorbed molecules evaluated by QCM ( N QCM ) show good agreement with those counted from the STM images ( N STM ) within the error of ±25%. The results ensure the QCM capability for controlling the deposition number of organic molecules with high accuracy, that is, if one needs to deposit 100 molecules on the substrate, QCM control promises deposition of 100 ± 25 molecules.

Band gap opening of a single-layer graphene nanoribbon (sGNR) sitting on another sGNR, fabricated by drop casting GNR solution on Au(111) substrate in air, was studied by means of scanning tunneling microscopy and spectroscopy in an ultra-high vacuum at 78 K and 300 K. GNRs with a width of ∼45 nm were prepared by unzipping double-walled carbon nanotubes (diameter ∼15 nm) using the ultrasonic method. In contrast to atomically-flat GNRs fabricated via the bottom-up process, the drop cast sGNRs were buckled on Au(111), i.e., some local points of the sGNR are in contact with the substrate (d ∼ 0.5 nm), but other parts float (d ∼ 1-3 nm), where d denotes the measured distance between the sGNR and the substrate. In spite of the fact that the nanoribbons were buckled, dI/dV maps confirmed that each buckled sGNR had a metallic character (∼3.5 G o ) with considerable uniform local density of states, comparable to a flat sGNR. However, when two sGNRs crossed each other, the crossed areas showed a band gap between -50 and +200 meV around the Fermi energy, i.e., the only upper sGNR electronic property changed from metallic to p-type semiconducting, which was not due to the bending, but the electronic interactions between the up and down sGNRs.

An important step toward molecule-based electronics is to realize a robust and well-ordered molecular network at room temperature. To this end, one key challenge is tuning the molecule-substrate electronic interactions that influence not only the molecular selfassembly but also the stability of the resulting structures. In this study, we investigate the film formation of π-conjugated metal-free phthalocyanine molecules on a 3d-bcc-Fe(001) whisker substrate at 300 K by using ultra-high-vacuum scanning tunneling microscopy. On bare Fe(001), hybridization between the molecular π and the Fe(001) d-states prevents the molecular assembly, resulting in the disordered patchy structures. The second- and third-layer molecules form densely packed films, while the morphologies show clear difference. The second-layer molecules partially form p(5 × 5)-ordered films with the rectangular edges aligned along the [100] and [010] directions, while the edges of the third-layer films are rounded. Remarkably, such film morphologies are stable even at 300 K. These findings suggest that the molecular self-assembly and the resulting morphologies in the second and third layers are affected by the substrate bcc(001), despite that the Fe-d states hybridize only with the first-layer molecules. The possible mechanism is discussed with the kinetic Monte Carlo simulation.

The genus Mesoplodon (Cetacea: Odontoceti: Ziphiidae) is one of the few cetacean genera with the karyotype 2n = 42. The 2n = 42 karyotype of M. europaeus and M. carlhubbsi is largely consistent with the general cetacean karyotype 2n = 44, although other 2n = 42 karyotypes do not exhibit clear homologies with the general cetacean karyotype. Therefore, the chromosomes of Mesoplodon species may be the key to understanding cetacean karyological evolution. In the present study, the male karyotypes of M. stejnegeri and M. carlhubbsi were examined. In both species, the diploid number of the male karyotype was 42. Both species had the following characteristics: 1) a huge subtelocentric X chromosome with a large C-block; 2) a small metacentric Y chromosome; 3) nucleolus organizer regions (NORs) in the terminal regions of a large autosome and one or two small metacentric autosomes; 4) small metacentric autosomes; 5) large submetacentric and subtelocentric autosomes; 6) less accumulated C-heterochromatin in the centromeric region; and 7) heteromorphism in C-heterochromatin accumulation between homologues. Characteristics 1 and 3 are peculiar to only the karyotypes of Mesoplodon species, whereas characteristics 4, 5, 6, and 7 are also found in the species with the general cetacean karyotype 2n = 44.

This study investigated the accumulation of polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues (OH-PBDEs and MeO-PBDEs) in the blood of harbor porpoises, Dall's porpoises, and finless porpoises stranded or bycaught in Japanese coastal waters and in the North Pacific Ocean. Moreover, we suggested the origins of these contaminants and the factors affecting their pattern of accumulation. Levels of PBDEs in Dall's porpoises were one order of magnitude greater than those in the other species. OH-PBDE and MeO-PBDE levels were comparable to those of PBDEs. However, no correlation was found between the levels of OH-PBDEs and PBDEs, whereas a strong correlation was found between that of OH-PBDEs and MeO-PBDEs (p < 0.001). 6OH-BDE47, reported compound biosynthesized by marine low-trophic level organisms, was the dominant congener. These results suggest that PBDEs found in these porpoise species derive from flame retardants, but OH-PBDEs and MeO-PBDEs are mainly of natural origins., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A clean tungsten (W) tip apex with a robust atomic plane is required for producing a stable tunneling electron emission under strong electric fields. Because a tip apex fabricated from a wire by aqueous chemical etching is covered by impurity layers, heating treatment in ultra-high vacuum is experimentally known to be necessary. However, strong heating frequently melts the tip apex and causes unstable electron emissions. We investigated quantitatively the tip apex and found a useful method to prepare a tip with stable tunneling electron emissions by controlling electron-bombardment heating power. Careful characterizations of the tip structures were performed with combinations of using field emission I-V curves, scanning electron microscopy, X-ray diffraction (transmitted Debye-Scherrer and Laue) with micro-parabola capillary, field ion microscopy, and field emission microscopy. Tips were chemically etched from (1) polycrystalline W wires (grain size ∼1000 nm) and (2) long-time heated W wires (grain size larger than 1 mm). Heating by 10-40 W (10 s) was found to be good enough to remove oxide layers and produced stable electron emission; however, around 60 W (10 s) heating was threshold power to increase the tip radius, typically +10 ± 5 nm (onset of melting). Further, the grain size of ∼1000 nm was necessary to obtain a conical shape tip apex.

Sulfuric acid-treated liver extracts of representative high-trophic level Japanese animals were analyzed by toxic identification and evaluation (TIE) with chemically activated luciferase expression (CALUX) and chemical analysis to elucidate androgen receptor (AR) antagonistic activities and potential contributions of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The activities were detected in striped dolphins (n = 5), Stejneger's beaked whales (n = 6), golden eagle (n = 1), and Steller's sea eagle (n = 1) with CALUX-flutamide equivalents (FluEQs) as follow: 38 (20-52), 47 (21-96), 5.0, and 80 μg FluEQ/g-lipid, respectively. The AR antagonism was detected in limited number of specimens at lower levels for finless porpoise, raccoon dog, and common cormorant. Theoretical activities (Theo-FluEQs) were calculated using the concentration of OCPs and PCBs and their IC25-based relative potency (REP) values. These total contribution to CALUX-FluEQ was 126%, 84%, 53%, 55%, and 44% for striped dolphin, Steller's sea eagle, Stejneger's beaked whale, finless porpoise, and golden eagle, respectively, and the main contributor was p,p'-DDE. However, most of the activities for raccoon dog (7.6%) and common cormorant (17%) could not be explained by OCPs and PCBs. This suggests other unknown compounds could function as AR antagonists in these terrestrial species.

Lobomycosis is a chronic fungal disease caused by the etiologic agent, Lacazia loboi, in the skin and subcutaneous tissues in humans and dolphins in tropical and transitional tropical climates. An Indo-Pacific bottlenose dolphin (Tursiops aduncus) stranded in Kagoshima, Japan, had severe skin lesions characterized by granulomatous reactions and hyperkeratosis that were similar to those of the lobomycosis, but no fungal organism was observed in the skin lesion. In this paper, we report a stranded Indo-Pacific bottlenose dolphin with lobomycosis-like lesions based on pathological examinations in Japan.

A simple method for fabricating single-layer graphene nanoribbons (sGNRs) from double-walled carbon nanotubes (DWNTs) was developed. A sonication treatment was employed to unzip the DWNTs by inducing defects in them through annealing at 500 °C. The unzipped DWNTs yielded double-layered GNRs (dGNRs). Further sonication allowed each dGNR to be unpeeled into two sGNRs. Purification performed using a high-speed centrifuge ensured that more than 99% of the formed GNRs were sGNRs. The changes induced in the electrical properties of the obtained sGNR by the absorption of nanoparticles of planar molecule, naphthalenediimide (NDI), were investigated. The shape of the I-V curve of the sGNRs varied with the number of NDI nanoparticles adsorbed. This was suggestive of the existence of a band gap at the narrow-necked part near the NDI-adsorbing area of the sGNRs.

One hundred and twenty stranding events of Stejneger's beaked whales were reported in Japan between 1999 and 2011. The purpose of this study is to introduce pathological data and to discuss probable causes of death for 44 Stejneger's beaked whales among them. The significant pathological findings were the pulmonary edema, parasitic granulomatous nephritis, emaciation, amyloidosis, suppurative bronchopneumonia and so on. The probable causes of death were categorized as noninfectious in 43 of the cases, which included drowning, starvation and secondary amyloidosis. One individual was diagnosed with septicemia, which was the only example of an infectious disease. Because we could not always perform advanced analyses, such as microbiology tests, biotoxin examinations or contaminant analyses, the finality of our findings may be impaired. However, the present study has broad implications on the causes of death of Stejneger's beaked whales of the seas around Japan, which are valuable for the future studies and for the detection of emerging diseases.

Background: The evolution of oogamy from isogamy, an important biological event, can be summarized as follows: morphologically similar gametes (isogametes) differentiated into small "male" and large "female" motile gametes during anisogamy, from which immotile female gametes (eggs) evolved. The volvocine green algae represent a model lineage to study this type of sex evolution and show two types of gametic unions: conjugation between isogametes outside the parental colonies (external fertilization during isogamy) and fertilization between small motile gametes (sperm) and large gametes (eggs) inside the female colony (internal fertilization during anisogamy and oogamy). Although recent cultural studies on volvocine algae revealed morphological diversity and molecular genetic data of sexual reproduction, an intermediate type of union between these two gametic unions has not been identified., Results: We identified a novel colonial volvocine genus, Colemanosphaera, which produces bundles of spindle-shaped male gametes through successive divisions of colonial cells. Obligately anisogamous conjugation between male and female motile gametes occurred outside the female colony (external fertilization during anisogamy). This new genus contains 16- or 32-celled spheroidal colonies similar to those of the volvocine genera Yamagishiella and Eudorina. However, Colemanosphaera can be clearly distinguished from these two genera based on its sister phylogenetic position to the enigmatic flattened colonial volvocine Platydorina and external fertilization during anisogamy. Two species of Colemanosphaera were found in a Japanese lake; these species are also distributed in European freshwaters based on a published sequence of an Austrian strain and the original description of Pandorina charkowiensis from Ukraine., Conclusions: Based on phylogeny and morphological data, this novel genus exhibits a missing link between Platydorina and the typical spheroidal colonial volvocine members such as Pandorina or Yamagishiella. Considering the external obligate anisogamy, oogamy evolution may have been preceded by the transition from external to internal fertilization during anisogamy within the volvocine green algae.

Information on accumulation of halogenated phenolic contaminants in the blood of marine mammal is limited. The present study, we determined the residue levels and patterns of chlorinated and brominated phenolic contaminants (OH-PCBs, OH-PBDEs and bromophenols) in the blood collected from pinnipeds (northern fur seal, spotted seal, Steller sea lion and ribbon seal) and small cetaceans (harbor porpoise and Dall's porpoise) from Japanese coastal waters. Concentrations of PCBs and OH-PCBs found in pinnipeds were the same as in small cetaceans living in the same coastal area. However, significantly lower concentrations of brominated compounds (PBDEs, MeO-PBDEs, OH-PBDEs) were found in the blood of pinnipeds than the levels found in cetacean species which live same area (p < 0.05). This difference of accumulation pattern suggested pinnipeds have an enhanced capability to degrade organobromine compounds relative to cetaceans., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Organic nanomolecules have become one of the most attractive materials for new nanoelectronics devices. Understanding of the electronic density of states around the Fermi energy of low-dimensional molecules is crucial in designing the electronic properties of molecular devices. The low dimensionality of nanomolecules results in new electronic properties owing to their unique symmetry. Scanning tunneling spectroscopy is one of the most effective techniques for studying the electronic states of nanomolecules, particularly near the Fermi energy (±1.5 eV), whereas these molecular electronic states are frequently buried by the tunneling probability background in tunneling spectroscopy, resulting in incorrect determination of the molecular electronic states. Here, we demonstrate how to recover nanomolecular electronic states from dI/dV curves obtained by tunneling spectroscopy. Precise local density of states (LDOS) peaks for low-dimensional nanostructures (monolayer ultrathin films, one-dimensional chains, and single molecules) of phthalocyanine (H2Pc) molecules grown on noble fcc-Cu(111) were obtained.

The present study investigated polychlorinated biphenyls (PCBs) and hydroxylated metabolites of PCBs (OH-PCBs) in blood from three porpoise species: finless porpoises (Neophocaena phocaenoides), harbor porpoises (Phocoena phocoena), and Dall's porpoises (Phocoenoides dalli). The porpoises were found stranded or were bycaught along the Japanese coast. Concentrations of OH-PCB were the highest in Dall's porpoises (58pgg(-1) wet wt), second highest in finless porpoises (20pgg(-1) wet wt), and lowest in harbor porpoises (8.3pgg(-1) wet wt). The concentrations in Dall's porpoises were significantly higher than the concentrations in finless porpoises and harbor porpoises (p<0.05 and p<0.01, respectively). There was a positive correlation between PCB and OH-PCB concentrations (r=0.67, p<0.001), suggesting the possible concentration-dependent induction of CYP enzymes. The three porpoise species may have exceptionally low metabolic capacities compared with other marine and terrestrial mammals, because low OH-PCB/PCB concentration ratios were found, which were 0.0016 for Dall's porpoises, 0.0013 for harbor porpoises, and 0.00058 for finless porpoises. Distinct differences in the OH-PCB congener patterns were observed for the three species, even though they are taxonomically closely related., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The magnetoresistance of a hydrogen-phthalocyanine molecule placed on an antiferromagnetic Mn(001) surface and contacted by a ferromagnetic Fe electrode is investigated using density functional theory based transport calculations and low-temperature scanning tunneling microscopy. A large and negative magnetoresistance ratio of ~50% is observed in combination with a high conductance. The effect originates from a lowest unoccupied molecular orbital (LUMO) doublet placed almost in resonance with the Fermi energy. As a consequence, irrespective of the mutual alignment of magnetizations, electron transport is always dominated by resonant transmission of Mn-majority charge carries going through LUMO levels.

A nanoscale molecular switch can be used to store information in a single molecule. Although the switching process can be detected electrically in the form of a change in the molecule's conductance, adding spin functionality to molecular switches is a key concept for realizing molecular spintronic devices. Here we show that iron-based spin-crossover molecules can be individually and reproducibly switched between a combined high-spin, high-conduction state and a low-spin, low-conduction state, provided the individual molecule is decoupled from a metallic substrate by a thin insulating layer. These results represent a step to achieving combined spin and conduction switching functionality on the level of individual molecules.

We evaluated the applicability of combining in vitro bioassays with instrument analyses to identify potential endocrine disrupting pollutants in sulfuric acid-treated extracts of liver and/or blubber of high trophic-level animals. Dioxin-like and androgen receptor (AR) antagonistic activities were observed in Baikal seals, common cormorants, raccoon dogs, and finless porpoises by using a panel of rat and human cell-based chemical-activated luciferase gene expression (CALUX) reporter gene bioassays. On the other hand, no activity was detected in estrogen receptor α (ERα)-, glucocorticoid receptor (GR)-, progesterone receptor (PR)-, and peroxisome proliferator-activated receptor γ2 (PPARγ2)-CALUX assays with the sample amount applied. All individual samples (n = 66) showed dioxin-like activity, with values ranging from 21 to 5500 pg CALUX-2,3,7,8-tetrachlorodibenzo-p-dioxin equivalent (TEQ)/g-lipid. Because dioxins are expected to be strong contributors to CALUX-TEQs, the median theoretical contribution of dioxins calculated from the result of chemical analysis to the experimental CALUX-TEQs was estimated to explain up to 130% for all the tested samples (n = 54). Baikal seal extracts (n = 31), but not other extracts, induced AR antagonistic activities that were 8-150 μg CALUX-flutamide equivalent (FluEQ)/g-lipid. p,p'-DDE was identified as an important causative compound for the activity, and its median theoretical contribution to the experimental CALUX-FluEQs was 59% for the tested Baikal seal tissues (n = 25). Our results demonstrate that combining in vitro CALUX assays with instrument analysis is useful for identifying persistent organic pollutant-like compounds in the tissue of wild animals on the basis of in vitro endocrine disruption toxicity.

We determined the residue levels and patterns of hydroxylated polybrominated diphenyl ethers (OH-PBDEs), and related compounds, such as PBDEs, methoxylated PBDEs (MeO-PBDEs), and bromophenols (BPhs) in the blood of eleven cetacean species stranded along the Japanese coasts. The dominant OH- and MeO-PBDE isomers found in all cetaceans were 6OH-BDE47 and 6MeO-BDE47. Additionally, 2,4,6-triBPh was dominant isomer in all cetaceans. In contrast, specific differences in the distribution of para- and meta- OH-PBDE isomers and some BPhs (potential PBDEs metabolites) were found among the cetaceans. Residue levels of ΣMeO-PBDEs and 6OH-BDE47 + 2'OH-BDE68, and 2,4,6-triBPh and 6OH-BDE47 + 2'OH-BDE68 showed a significant positive correlation. These results may suggest that the large percentages of OH-PBDEs, MeO-PBDEs and 2,4,6-triBPh might share common source (i.e. biosynthesis by marine organisms), or metabolic pathway in cetacean species. Significant correlations were found between the concentrations of BDE99 and 2,4,5-triBPh. This result suggested that 2,4,5-triBPh in cetaceans could be a metabolite of BDE99., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The chemical form of Ag in the livers of five species of marine mammals was examined using X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies. The XAFS analysis suggested that Ag(2)Se was present in the livers of the Franciscana dolphin (Pontoporia blainvillei), Dall's porpoise (Phocoenoides dalli), and Baird's beaked whale (Berardius bairdii), whereas Ag(2)S was present in the livers of the striped dolphin (Stenella coeruleoalba) and pygmy killer whale (Feresa attenuata). XRF spectroscopy results revealed that the distribution patterns of Ag and Se in a thin section of the liver of the Franciscana dolphin were the same; this also implied that Ag was associated with Se in the liver. Thus, the interaction of Ag with Se or S may offer significant protection against the toxicity of Ag in marine mammals. The formation of either Ag(2)Se or Ag(2)S might depend on the Hg levels in the liver. Ag(2)Se was observed in liver samples with relatively high Ag/Hg ratio, whereas liver samples with low Ag/Hg ratio contained Ag(2)S.

Magnetoresistance is a change in the resistance of a material system caused by an applied magnetic field. Giant magnetoresistance occurs in structures containing ferromagnetic contacts separated by a metallic non-magnetic spacer, and is now the basis of read heads for hard drives and for new forms of random access memory. Using an insulator (for example, a molecular thin film) rather than a metal as the spacer gives rise to tunnelling magnetoresistance, which typically produces a larger change in resistance for a given magnetic field strength, but also yields higher resistances, which are a disadvantage for real device operation. Here, we demonstrate giant magnetoresistance across a single, non-magnetic hydrogen phthalocyanine molecule contacted by the ferromagnetic tip of a scanning tunnelling microscope. We measure the magnetoresistance to be 60% and the conductance to be 0.26G(0), where G(0) is the quantum of conductance. Theoretical analysis identifies spin-dependent hybridization of molecular and electrode orbitals as the cause of the large magnetoresistance.

Herpesviral infections have been documented in some cetaceans; however, they have not yet been identified in species in the western North Pacific. In the present study, 178 tissue samples from 76 stranded cetacean individuals were tested for the presence of herpesviruses. Herpesvirus genomic DNA fragments surrounding the DNA polymerase gene were amplified in samples from four individuals. TA cloning and direct sequencing of these DNA fragments revealed the presence of two novel alphaherpesviruses, and two novel gammaherpesviruses in the four cetacean individuals. The alphaherpesviruses were associated with the lung tissue of a false killer whale (Pseudorca crassidens), and with the mucus of a melon-headed whale (Peponocephala electra). The gammaherpesviruses were found in the lymph tissues of a Stejneger's beaked whale (Mesoplodon stejnegeri) and a sperm whale (Physeter macrocephalus). The phylogenetic tree using amino acid sequences of the DNA polymerase gene supported the inclusion of the novel viruses identified here in a single monophyletic group containing alphaherpesviruses from other Atlantic cetacean species. Conversely, the novel gammaherpesviruses formed an independent clade distant from other known cetacean gammaherpesviruses.

Contamination status of brominated flame retardants (BFRs) and persistent organic pollutants (POPs) in blubber of finless porpoises (Neophocaena phocaenoides) stranded along the coasts of Seto Inland Sea and Omura Bay in Japan were investigated. Levels of PCBs, DDTs and CHLs were significantly higher than those of HCHs, HCB, PBDEs and HBCDs. Concentrations of PBDEs and HBCDs, as well as organochlorine compounds in males increased with body length (p<0.05). Among 14 PBDE congeners analyzed, BDE-47 was the predominant, which is similar to those generally reported in biota. PBDEs, HBCDs and PCBs showed no obvious temporal trend in concentrations during the study period, suggesting continuous environmental release of these chemicals. On the other hand, levels of DDT, CHLs and HCHs have decreased. Concentrations of PCBs in liver trematode infected individuals were significantly higher than those in not infected individuals, implying there could be a relationship between contaminant levels and parasitic infection., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Magnetoelectric coupling allows the magnetic state of a material to be changed by an applied electric field. To date, this phenomenon has mainly been observed in insulating materials such as complex multiferroic oxides. Bulk metallic systems do not exhibit magnetoelectric coupling, because applied electric fields are screened by conduction electrons. We demonstrate strong magnetoelectric coupling at the surface of thin iron films using the electric field from a scanning tunnelling microscope, and are able to write, store and read information to areas with sides of a few nanometres. Our work demonstrates that high-density, non-volatile information storage is possible in metals.

In this study, we determined the residue levels and patterns of polychlorinated biphenyls (PCBs) and hydroxylated PCBs (OH-PCBs) in the blood from eight species of toothed whales and three species of baleen whales stranded along the Japanese coast during 1999-2007. Penta- through hepta-chlorinated PCB congeners were the dominant homologue groups in all cetaceans. In contrast, specific differences in the distribution of dominant OH-PCB isomers and homologues were found among the cetacean species. In five species of toothed whales (melon-headed whale, Stejneger's beaked whale, Pacific white-sided dolphin, Blainville's beaked whale, and killer whale), the predominant homologues were OH-penta-PCBs followed by OH-tetra-PCBs and OH-tri-PCBs. The predominant homologues of finless porpoise and beluga whale were OH-penta-PCBs followed by OH-hexa-PCBs and OH-tri-PCBs. The predominant OH-PCB isomers were para-OH-PCBs such as 4OH-CB26, 4'OH-CB25/4'OH-CB26/4OH-CB31, 4OH-CB70, 4'OH-CB72, 4'OH-CB97, 4'OH-CB101/4'OH-CB120, and 4OH-CB107/4'OH-CB108 in toothed whales. In three baleen whales (common minke whale, Bryde's whale, and humpback whale) and in sperm whale (which is a toothed whale), OH-octa-PCB (4OH-CB202) was the predominant homologue group accounting for 40-80% of the total OH-PCB concentrations. The differences in concentrations and profiles of OH-PCBs may suggest species-specific diets, metabolic capability, and the transthyretin (TTR) binding specificity. These results reveal that the accumulation profiles of OH-PCBs in cetacean blood are entirely different from the profiles found in pinnipeds, polar bear, and humans.

Organotins (OTs) are globally ubiquitous contaminants. Contamination of OTs, particularly butyltins (BTs), has been suspected to cause immunosuppressive effects leading to subsequent infectious diseases or opportunistic infection by pathogens in marine mammals. In the present study, we collected individuals from five different populations of finless porpoises (Neophocaena phocaenoides) from coastal areas of Japan (Seto Inland Sea, Ise Bay, Omura Bay, and Pacific coast) and Hong Kong, and measured OT concentrations in their livers. In addition, infection status of lung nematodes and liver trematodes was also observed to analyze the relationship between OT contamination and parasitic infection in finless porpoises. Hepatic OT concentrations were highest in the Hong Kong population, while levels in the Japanese populations were equivalent to those of other cetaceans from different locations. OT levels in Japan have been decreasing in the past few decades, while OT contamination has shown little improvement in Hong Kong. Observation of parasite infection in Seto Inland Sea porpoises revealed that 16 and 11 out of 22 individuals were infected by lung nematodes and liver trematodes, respectively. Additionally, a significant association between BT levels and parasitic infection status of lung nematodes was detected. Thus, the present study suggests that BTs could be a factor affecting parasitic infection, especially the presence or severity of lung nematodes in finless porpoises. Since chemical exposure may alter the susceptibility of organisms to infectious diseases, the interaction of chemical contamination with infectious diseases needs to be investigated in greater depth to understand the risk of population decline due to these factors in marine mammals.

Organohalogen contaminants including PCBs, DDTs, CHLs, HCHs, HCB, PBDEs and HBCDs were determined in striped dolphins (Stenella coeruleoalba) found stranded at Gogo-shima (n=6, 2003) and collected from Taiji (n=15, 1978-1992) in Japan. All target compounds were significantly detected in all the specimens, indicating ubiquitous contamination of oceanic cetaceans in northwest Pacific Ocean. Examination of body distribution of organohalogens in the six specimens from Gogo-shima showed no significant difference in concentrations among the analyzed tissues, except for brain, which had lower levels possibly due to the existence of blood-brain barrier. For evaluating temporal trends, archived blubber samples of adult male stripped dolphins collected in 1978, 1979, 1986 and 1992 were analyzed. Concentrations of PCBs, DDTs and HCHs did not change significantly during 1978-2003. In contrast, remarkable increasing trends of PBDEs and HBCDs were observed, suggesting growing consumption in Japan and surrounding countries in recent years.

Cranial variation in 129 pantropical spotted dolphins (Stenella attenuata) from the western and eastern tropical Pacific was investigated morphometrically. This study revealed significant sexual dimorphism in the dolphin skulls. Differences between the genders were mostly recorded in the rostrum and braincase, which are wider and more robust in males. This sexual variation was interpreted in terms of differences in behavioral and life-history strategies between genders. Geographical variation among populations of the eastern tropical Pacific (ETP), Japan, and Taiwan was also significant, with different sexual patterns. While no clear trend in geographical variation was detected in males, there was a positive relationship in females between morphological differences and geographical distance. That is, Japanese and Taiwanese female specimens were morphologically more similar than revealed by other pairwise comparisons between them and the ETP specimens. Moreover, two canonical discriminant functions further discriminated the three populations for males and females, respectively. The two functions showed that the rostrum and braincase are the principal elements in discrimination of geographical variation in males, while only the rostrum is the major discriminant morph of geographical variation in females. In addition, tests based on Mahalanobis distance-squares were conducted to assign six specimens from the western tropical Pacific to the above three populations to clarify the similarities among them.

Polybrominated diphenyl ethers (PBDEs) and organochlorine compounds (OCs) were determined in the blubber of 55 melon-headed whales (Peponocephala electra) mass stranded along the Japanese coasts since 1982. DDTs and PCBs were predominant in all the specimens investigated. In whales that died during the latest event in 2006, concentrations of PBDEs (190-510 ng/g lipid wt) were approximately two orders of magnitude lower than DDTs and PCBs, but comparable with HCHs and HCB. Maternal transfer of PBDEs to offspring through the whole reproductive process was estimated to be 85% of the mother's body burden, while that occurring during gestation was much lower (2.6-3.5%). Concentrations of PCBs, DDTs, and HCB were lower in melon-headed whales stranded after the year 2000 than those stranded in 1982, whereas PBDE and CHL levels showed a temporal increase during the past 20 years, suggesting that the peak of their usage and contamination occurred after the year 1982.

As a result of the phase-out of production of perfluorooctanesulfonyl-based compounds by a major producer, concentrations of perfluorooctanesulfonate (PFOS) in marine mammals from North American and European coastal waters have been declining since the early 2000s. Nevertheless, temporal trends in perfluorochemical (PFC) concentrations in marine mammals from Asian coastal waters have not been examined. In this study, PFCs were determined in livers of melon-headed whales (Peponocephala electra) collected along the coast of Japan, from three mass strandings that occurred during the past 25 years. Concentrations of nine PFCs were determined in livers of 48 melon-headed whales that were collected during strandings in 1982, 2001/2002, and 2006. In addition, concentrations in liver tissues obtained from two pregnant females and their fetuses were compared for determination of transplacental transfer rates of PFCs during gestation. PFOS and perfluorooctanesulfonamide (PFOSA) were the predominant PFCs found in livers of melon-headed whales collected in 1982 (n = 22). PFOS, PFOSA, perfluoroundecanoate (PFUnDA), perfluorododecanoate (PFDoDA), perfluorodecanoate (PFDA), and perfluorononanoate (PFNA) were found in whales collected in 2001/2002 (n = 21) and in 2006 (n = 5). Concentrations of PFOS and PFOSA were approximately 10-fold higher in 2001/2002 than in 1982. Whereas concentrations of PFOSA then declined by 2-fold from 2001/ 2002 to 2006, concentrations of PFOS and perfluorocarboxylates did not decline after 2001/2002. Conversely, concentrations of PFNA and PFDA increased significantly from 2001/2002 to 2006. The proportion of perfluoroalkylsulfonates in total PFC concentrations decreased from 75% in 1982 to 51% in 2006. Conversely, the contribution of perfluorocarboxylates to total PFC concentrations increased from 25% in 1982 to 49% in 2006. PFUnDA was the major perfluorocarboxylate found in whale livers collected after 2000. Analysis of paired samples of mother-fetus demonstrated that the transplacental transfer rates of PFCs were higher than those for PCBs and PBDEs.

One feature of the alpha3-peptide, which has the amino acid sequence of (Leu-Glu-Thr-Leu-Ala-Lys-Ala)(3), that distinguishes it from many other alpha-helix-forming peptides is its ability to form fibrous assemblies that can be observed by transmission electron microscopy. In this study, the effects of Ala-->Gln substitution at the e (5th) or g (7th) position in the above heptad sequence of the alpha3-peptide on the formation of alpha-helix and fibrous assemblies were investigated by circular dichroism spectral measurement and atomic force microscopy. The 5Qalpha3-peptide obtained by Ala-->Gln substitution at the e position of the alpha3-peptide was found to form very short fibrils with long-elliptical shape, whereas the 7Qalpha3-peptide with Gln residues at the g position lost its ability to form such assemblies, in spite of alpha-helix formation in both peptides; the stabilities of both peptides decreased. These results indicate that Ala residues at the g position in the heptad sequence of the alpha3-peptide are key residues for the formation of fibrous assemblies, which may be due to hydrophobic interactions between alpha-helical bundle surfaces.