Temporal variation in maximum cell-specific nitrification rate

The cell numbers of ammonia-oxidising bacteria (AOBs), Nitrospira and Nitrobacter in activated sludge used to treat wastewater from a thermal power plant in Japan were examined for nine months using a real-time PCR quantification technique. AOB cell numbers ranged 2.8 x 10(10)-2.3 x 10(11) cell/L. The amoA clone analysis showed that the only Nitrosomonas halophila was responsible for ammonia oxidation over the period. Nitrospira were in the range of 2.6 x 10(9)-2.4 x 10(10) cell/L and Nitrobacter were less than 1% as common as Nitrospira. Meanwhile, maximum nitrification rates, maximum ammonia- and nitrite-oxidation rates obtained from aerobic batch tests, ranged 0.5-1.3 mmol-N/L h and 1.0-2.5 mmol-N/L h, respectively. No clear correlations were observed between the cell numbers of AOBs or Nitrospira and their maximum rates, because the maximum cell-specific ammonia- and nitrite-oxidation rates varied remarkably over the ranges of 1.1-11.9 and 2.4-21.6 fmol-N/cell h, respectively. To explore the factors controlling maximum cell-specific nitrification rates, the relationship to influent nitrogen loads per AOB or Nitrospira cell numbers was investigated. Fairly good correlations were obtained. Considering the effluent ammonia and nitrite concentrations were zero and only Nitrosomonas halophila had a role in ammonia oxidation over the period, we conclude that the amount of nitrogen oxidised per AOB or Nitrospira cell numbers likely controls maximum cell-specific ammonia- or nitrite-oxidation rates, respectively.

Glycoprotein (GP) VI dimer as a major collagen-binding site of native platelets: direct evidence obtained with dimeric GPVI-specific Fabs

BACKGROUND

The platelet collagen receptor glycoprotein (GP) VI is suggested to exist as a dimer on the platelet surface, but no direct proof of the functional importance of dimer formation has been provided.

OBJECTIVES

To obtain direct evidence for GPVI dimers on the platelet membrane and their functional importance, Fab antibodies were developed that bind to GPVI dimer (GPVI-Fc2) but not to GPVI monomer (GPVIex) through a phage display method.

RESULTS

Six Fabs were found: B-F, only reactive with GPVI-Fc2, and A, mainly reactive with GPVI-Fc2, with some reactivity towards GPVIex; each Fab (Fab-dHLX-MH) forms a bivalent dimer (b-Fab) by dimerizing the dHLX domains from two Fab molecules. Fab F was subcloned to a monovalent format by deleting its dHLX domain. All b-Fabs induced platelet aggregation, but the monomeric form of Fab F (m-Fab-F) specifically inhibited collagen-induced aggregation. All b-Fabs and m-Fab-F inhibited GPVI-Fc2 binding to fibrous collagen. Immunoblotting showed that b-Fab-F and m-Fab-F bound weakly to GPVI-Fc2. Adding the anti-GPVI monoclonal antibody 204-11 increased the B(max) of m-Fab-F binding to GPVI-Fc2, suggesting that 204-11 binds to GPVI-Fc2 molecules not already in the appropriate conformation to recognize the Fab, converting them to a conformation reactive to the Fab.

CONCLUSIONS

GPVI forms a specific structure by dimerization that is necessary for the binding of this receptor to collagen fibrils. The binding of m-Fab-F to platelets directly demonstrates that GPVI is present as a functionally relevant dimer on the platelet surface.

Controlling the phase matching conditions of optical parametric chirped-pulse amplification using partially deuterated KDP

Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.

Personal imports of drugs to Japan in 2005--an analysis of import certificates

BACKGROUND

Personal imports of unapproved drugs are made by physicians and patients in Japan. Such imports require submission of a request for an import certificate from the Regional Bureau of Health and Welfare (RBHW). So far, there have been few reports on personal imports of drugs in Japan.

OBJECTIVE

To assess the extent and nature of personal imports of drugs in Japan.

METHODS

The date, product name and amount of drug imported were provided by RBHW for each personal import made by physicians in 2005. All imports were classified into several groups including whether they were for 'prescription drugs for non-cosmetic use (PDNC)' or 'prescription drugs for cosmetic use (PDC)'. Identification of PDNC was made by International Non-proprietary Name (INN). All drugs were classified under therapeutic groups. For the most frequently imported unapproved drugs, the approval year in the US/EU and development status in Japan were recorded.

RESULTS

A total of 12 196 personal imports were initiated by physicians in 2005. 5428 were for PDNCs corresponding to 242 drugs by INN. 55 PDNCs were each the subject of 10 or more imports. 11 drugs (252 imports) out of the top 55 PDNCs were available on the Japanese market during 2005 and 44 (4713 imports) were not approved. Of the 44 unapproved drugs, 11 (1019 imports) had been approved and 10 (2785 imports) were in the pre-registration phase as of December 31, 2006. Of the 44 unapproved drugs, 12 (1213 imports) were approved during 2000-2004, and 17 (3138 imports), during 1995-1999 in the US or EU. While the majority of imported drugs were antineoplastic drugs, drugs for various kinds of non-serious diseases were also imported.

CONCLUSIONS

A substantial number of unapproved drugs were being imported to Japan. A formal system for monitoring the use of those drugs should be established.

Inhibitory actions of the phosphatidylinositol 3-kinase inhibitor LY294002 on the human Kv1.5 channel

BACKGROUND AND PURPOSE

Kv1.5 channels conduct the ultra-rapid delayed rectifier potassium current (I(Kur)), and in humans, Kv1.5 channels are highly expressed in cardiac atria but are scarce in ventricles. Pharmacological blockade of human Kv1.5 (hKv1.5) has been regarded as effective for prevention and treatment of re-entry-based atrial tachyarrhythmias. Here we examined blockade of hKv1.5 channels by LY294002, a well-known inhibitor of phosphatidylinositol 3-kinase (PI3K).

EXPERIMENTAL APPROACH

hKv1.5 channels were heterologously expressed in Chinese hamster ovary cells. Effects of LY294002 on wild-type and mutant (T462C, H463C, T480A, R487V, A501V, I502A, I508A, L510A and V516A) hKv1.5 channels were examined by using the whole-cell patch-clamp method.

KEY RESULTS

LY294002 rapidly and reversibly inhibited hKv1.5 current in a concentration-dependent manner (IC(50) of 7.9 micromol.L(-1)). In contrast, wortmannin, a structurally distinct inhibitor of PI3K, had little inhibitory effect on hKv1.5 current. LY294002 block of hKv1.5 current developed with time during depolarizing voltage-clamp steps, and this blockade was also voltage-dependent with a steep increase over the voltage range for channel openings. The apparent binding (k(+1)) and unbinding (k(-1)) rate constants were calculated to be 1.6 micromol.L(-1) (-1).s(-1) and 5.7 s(-1) respectively. Inhibition by LY294002 was significantly reduced in several hKv1.5 mutant channels: T480A, R487V, I502A, I508A, L510A and V516A.

CONCLUSIONS AND IMPLICATIONS

LY294002 acts directly on hKv1.5 currents as an open channel blocker, independently of its effects on PI3K activity. Amino acid residues located in the pore region (Thr480, Arg487) and the S6 segment (Ile502, Ile508, Leu510, Val516) appear to constitute potential binding sites for LY294002.

Acetate uptake efficiency of polyphosphate-accumulating organisms under exposure to surfactants

We investigated the influence of surfactants such as linear alkylbenzene sulfonates (LAS) and alcohol ethoxylates (AE) on acetate uptake by polyphosphate-accumulating organisms (PAOs) under anaerobic conditions, using the phosphate requirement for acetate uptake (+DeltaP/-DeltaAc ratio). In order to estimate the +DeltaP/-DeltaAc ratio, anaerobic batch tests were conducted using activated sludge collected from an anaerobic/oxic sequencing batch reactor used to treat municipal wastewater continuously supplemented with a detergent containing LAS and AE. We demonstrated that LAS and AE have both positive and negative impacts on acetate uptake by PAOs. The disadvantage is that long-term exposure to the detergent inhibits acetate uptake by PAOs, thus deteriorating the efficiency, even if the surfactants are no longer present during the tests. Furthermore, the existence of LAS and/or AE with acetate further diminishes the efficiency. The advantage is that LAS and AE are potential sources of polyhydroxyalkanoate for PAOs, because acetate is produced from the surfactants under anaerobic conditions.

What do the indices of reproductive skew measure?

Several indices of reproductive skew that quantify the degree of unequal partitioning of reproductive output among individuals have been proposed without consensus on their merits and defects. We believe that the major reason for the disagreement is the lack of discussion on what the population parameter of skew (population skew or true skew) should measure. In our view, the skew index should be an unbiased estimate of a population skew, and the estimated skew needs to satisfy the following two conditions. First, if the group size is equal and the distribution of potential of reproductive output (pi), which is scaled by the proportion of the individual's to the total group reproductive output, is also fixed, skew remains constant even when the total number of offspring in the group changes. Second, if the group size is different, skew should have intuitive biological meaning. Our analyses revealed that, among various indices so far proposed, only the skews estimated by Kokko and Lindström's lambda and Morisita's I(delta) satisfy the first condition. However, the two indices estimate different population parameters, thus implying different biological meanings. Morisita's I(delta) is a linear function of CV(2) (squared coefficient of variation) of pi, and lambda is a positive function of [Formula: see text] when offspring number follows a multinomial distribution. In the special cases where a group consists of discrete classes of breeders and nonbreeders, lambda behaves roughly inversely parallel to the absolute number of breeders, while I(delta) moves almost parallel to the proportion of nonbreeders. Furthermore, lambda is sensitive to the total proportion of reproductive output possessed by the dominants but is relatively less sensitive to the number of subordinates. We discussed the possible situations where either of the two indices will be useful.

Absolute calibration of imaging plate for GeV electrons

An imaging plate has been used as a useful detector of energetic electrons in laser electron acceleration and laser fusion studies. The absolute sensitivity of an imaging plate was calibrated at 1 GeV electron energy using the injector Linac of SPring-8. The sensitivity curve obtained up to 100 MeV in a previous study was extended successfully to GeV range.

Operation with a single-channel thin-fibre arthroscope in patients with internal derangement of the temporomandibular joint

We evaluated the use of operation by single-puncture arthroscopy in 55 patients (62 joints) with locked temporomandibular joints (TMJ). We used a single-channel thin-fibre arthroscope (M & M Co., Tokyo, Japan) and a holuminium yttrium aluminium garnet (Ho:YAG) laser (Lumenis Co., Tokyo, Japan). The preoperative mean (SD) maximum interincisal measurement (distance between the edge of the lower and upper incisor) was 26.0 (4.9) mm, and it was increased by 15.0mm 12 weeks after operation. The preoperative mean (SD) visual analogue score (VAS) was 6.3(2.0), and after 12 weeks it had been reduced to 1.6 (1.1). There were no other complaints. Single-puncture arthroscopy with the Ho:YAG laser is simple and useful. There were no other complications, and the results obtained were satisfactory.

Securing the coronoid process during a coronoidotomy

Sagittal application of a titanium mini screw in the coronoid process at the time of coronoidotomy is a very efficient method for easy removal.

Multi-millijoule, diode-pumped, cryogenically-cooled Yb:KY(WO(4))(2) chirped-pulse regenerative amplifier

A diode-pumped, cryogenically-cooled Yb:KYW regenerative amplifier utilizing chirped-pulse amplification and regenerative pulse shaping has been developed. An amplified pulse with an energy of 5.5 mJ and a broad bandwidth of 3.4 nm is achieved.

High-energy, diode-pumped, picosecond Yb:YAG chirped-pulse regenerative amplifier for pumping optical parametric chirped-pulse amplification

A diode-pumped, cryogenic-cooled Yb:YAG regenerative amplifier utilizing gain-narrowing has been developed. A 1.2-ns chirped-seed pulse was simultaneously amplified and compressed in the regenerative amplifier, which generated a 35-ps pulse with ~8-mJ of energy without a pulse compressor. Second-harmonics of the amplified pulse was used to pump picosecond two-color optical parametric amplification.

Identification of marker genes distinguishing human periodontal ligament cells from human mesenchymal stem cells and human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Molecular gene markers, which can distinguish human bone marrow mesenchymal stem cells from human fibroblasts, have recently been reported. Messenger RNA levels of tissue factor pathway inhibitor-2, major histocompatibility complex-DR-alpha, major histocompatibility complex-DR-beta, and neuroserpin are higher in human bone marrow mesenchymal stem cells than in human fibroblasts. However, human bone marrow mesenchymal stem cells express less apolipoprotein D mRNA than human fibroblasts. Periodontal ligament cells are a heterogeneous cell population including fibroblasts, mesenchymal stem cells, and progenitor cells of osteoblasts or cementoblasts. The use of molecular markers that distinguish human bone marrow mesenchymal stem cells from human fibroblasts may provide insight into the characteristics of human periodontal ligament cells. In this study, we compared the molecular markers of human periodontal ligament cells with those of human bone marrow mesenchymal stem cells and human gingival fibroblasts.

MATERIAL AND METHODS

The mRNA expression of the molecular gene markers was analyzed using real-time polymerase chain reaction. Statistical differences were determined with the two-sided Mann-Whitney U-test.

RESULTS

Messenger RNA levels of major histocompatibility complex-DR-alpha and major histocompatibility complex-DR-beta were lower and higher, respectively, in human periodontal ligament cells than in human bone marrow mesenchymal stem cells or human gingival fibroblasts. Human periodontal ligament cells showed the lowest apolipoprotein D mRNA levels among the three types of cells.

CONCLUSION

Human periodontal ligament cells may be distinguished from human bone marrow mesenchymal stem cells and human gingival fibroblasts by the genes for apolipoprotein D, major histocompatibility complex-DR-alpha, and major histocompatibility complex-DR-beta.

Ultra-broadband optical parametric chirped-pulse amplification using an Yb: LiYF(4) chirped-pulse amplification pump laser

We demonstrate ultra-broadband optical parametric chirpedpulse amplification of 300-nm bandwidth pumped by a broadband pulse delivered from a diode-pumped, cryogenically-cooled Yb:YLF chirped- pulse amplification laser.