Stability and nonlinear optical properties of ZnO nanoparticles

Photoluminescence (PL) of ZnO nanoparticles of different surface states and sizes grown by several methods has been measured. The origin of luminescence and dependence of the luminescence spectrum shape and intensity on 325 nm excitation laser power are studied. Strong ultraviolet emission at 3.26 eV, weak violet emission around 3.12 eV and weak green emission at 2.40 eV have been observed in 16 nm nanoparticles capped by octylamine grown by non-hydrolytic method. The nanoparticles are stable under high power laser radiation and their PL intensity increases nonlinearly with an increasing laser power. As the nanoparticle size decreases to 12 nm, high power laser produces nonradiative centers which may quench the luminescence in a degree. Nanoparticles of 8 nm capped by PVP and uncapped nanoparticles of 14 nm are unstable and their luminescence depends on the excitation laser power. High power laser can quench O vacancy emission and enhance ultraviolet emission in PVP capped nanoparticles while vacancy emission can not be quenched in uncapped nanoparticles.

Growth and properties of ZnO/Zn(1-x)MgxO core/shell nanoparticles

ZnO/Zn(0.9)Mg(0.1)O core/shell nanoparticles have been grown by employing metal cupferronate complex as precursors in organic solvents. ZnO cores are grown by quickly injecting their precursor at 250 degrees C while the shells are performed by slowly injecting their precursors at different temperatures. The grown nanoparticles are characterized by X-ray diffraction, photoluminescence microscopy, and transmission electron microscopy. The effects of the shell growth temperatures and precursor injecting rate are studied. Zn(0.9)Mg(0.1)O shells can epitaxially grow on ZnO cores when the shell growth temperature is lowered to 200 degrees C and the shell precursor is supplied slowly at a rate of 0.1 mmol/h. Increaseing shell supply rate or shell growth temperature results in homogenous growth of Zn(0.9)Mg(0.1)O nanoparticles. The shell growth can dramatically enhance core emission and cause a red shift on the core band edge emission.

Growth and properties of Zn(1-x)CdxO and Zn(1-x)CdxO/ZnO core/shell nanoparticles

Octylamine capped Zn(1-x)CdxO alloys and Zn(1-x)CdxO/ZnO core/shell nanoparticles have been grown by the thermal decomposing of zinc and cadmium cupferronates in organic solvents. Zn(1-x)CdxO alloys incorprated with different concentration of Cd have been grown by quickly injecting of their precursors at 200 degrees C. Zn(1-x)CdxO/ZnO core/shell nanoparticles are performed by slowly injecting of shell precursors at 180 degrees C. The prepared nanoparticles are characterized by X-ray diffraction, absorption spectrometer, Mirco-Raman spectrometer and transmission electron microscopy. The band gap of ZnCdO alloys shrinks linearly and the crystal lattice expands with an increase of Cd concentration. The growth of ZnO shells on ZnCdO cores enhances the core luminescence dramatically and results in a red shift in the absorption and emission of Zn(1-x)CdxO cores.

Production of cloned calves by combination treatment of both donor cells and early cloned embryos with 5-aza-2/-deoxycytidine and trichostatin A

We previously reported that treatment of both donor cells and early cloned embryos with a combination of 0.01 μM 5-aza-2(/)-Deoxycytidine (5-aza-dC) and 0.05 μM trichostatin A (TSA) significantly improved development of cloned bovine embryos in vitro. In the present study, we investigated the effect of this combination treatment on the in vivo development potency and postnatal survivability of cloned calves. Blastocysts (77 and 82 blastocysts derived from untreated (control) and treated groups, respectively) were individually transferred to recipient cows. Relative to the control group, the combination treatment of both donor cells and early embryos with 5-aza-dC and TSA dramatically increased the cleavage rate (49.2 vs 63.6%, P < 0.05) at 24 h of culture, and blastocyst development rate on Days 6 and 7 of culture (18.8 vs 33.9% and 27.1 vs 38.5% respectively, P < 0.05). Although pregnancy rate did not differ 40 d after transfer, it was lower in the treated than control group 90 d after transfer (7.8 vs 29.3%, P < 0.05). In the control group, there were three calves born to 77 recipients (only two survived beyond 60 d), whereas in the treated group, 17 calves were born to 82 recipients, and 11 survived beyond 60 d. In conclusion, a combination treatment of donor cells and early cloned embryos with 5-aza-dC and TSA significantly enhanced development of somatic cell cloned bovine embryos in vivo; cloning efficiency (number of surviving calves at 60 d of birth/number of recipient cows) was increased from 2.6 to 13.4%.

Purification and characterization of an antimicrobial peptide, insect defensin, from immunized house fly (Diptera: Muscidae)

The house fly, Musca domestica L. (Diptera: Muscidae), is involved in phoretic movement of pathogenic agents, but it has a very efficient defense mechanism against infection. It is believed that antimicrobial peptides play a significant role in the defense system of the house fly. Here, we isolated a peptide from the immunized house fly pupae, measured its molecular mass (3987.6 Da) by matrix-assisted laser desorption ionization/time of flight-mass spectrometry, and determined its amino acid sequence by using the Procise Protein Sequencing System (Applied Biosystems, Foster City, CA). The peptide was confirmed as a member of the insect defensin family. It displayed high activity against gram-positive bacteria but lower activity against gram-negative bacteria and fungi. Reverse transcription-polymerase chain reaction showed that the house fly defensin gene was constitutively expressed in naive pupae and strongly up-regulated after immunization. House fly defensin is an amphiphilic peptide with a structure similar to that of the CSalphabeta scaffold of insect defensin A from the flesh fly, Phormia terraenovae Robineau-Desvoidy. To our knowledge, this is the first isolated and characterized house fly antimicrobial peptide, and our work may provide useful information for developing pharmacologically active antimicrobial agents.

Expression of the genes encoding human leucocyte antigens-A, -B, -DP, -DQ and -G in gastric cancer patients

This study compared the expression of the genes encoding human leucocyte antigens (HLA)-A, -B, -DP, -DR and -G in peripheral blood mononuclear cells (PBMCs) in gastric cancer patients and healthy controls. Using reverse transcription-polymerase chain reaction, levels of classical HLA-A, -B, -DP and -DR and non-classical HLA-G mRNA were studied in 43 gastric cancer patients and 22 controls. In addition, the levels of HLA-A,B,C and -G antigens on the surface of PBMCs were measured in 30 gastric cancer patients and 15 controls using flow cytometry. The mean fluorescence intensity of HLA-A,B,C antigen in the gastric cancer group was significantly lower than in controls. The HLA-G antigen was mainly present on CD4(+)CD8(-) T-lymphocytes. The percentage of CD4(+)CD8(-) T-lymphocytes positive for HLA-G antigen was significantly lower in the gastric cancer group compared with the healthy controls. Levels of HLA-A, -B and -G mRNA in the gastric cancer group were significantly lower than in controls. The HLA-G mRNA levels were significantly lower in gastric cancer of histological grades III and IV than in grades I and II. These data may provide a novel diagnostic and research tool for gastric cancer.

Up-regulation of ABCB1/P-glycoprotein by escaping promoter hypermethylation indicates poor prognosis in hematologic malignancy patients with and without bone marrow transplantation

We investigated the correlation between MDR1 promoter methylation status and MDR1 expression in 228 hematologic malignancies patients and 90 healthy controls. High level of MDR1 mRNA correlated to promoter hypomethylation and strongly associated with poor prognosis indicated by 2-year survival rates, poor CR rate (without BMT) and high relapse rate (with BMT). Furthermore, relative luciferase activity of methylated MDR1 at promoter -50 region was significantly higher than that of the unmethylated. In addition, MDR1 in K562 cells elevated significantly after 5-Aza-dC treatment. In summary, MDR1 promoter hypomethylation conferred its up-regulation and indicated poor prognosis in patients with and without BMT.

CdO/ZnO core/shell nanostructures grown from single molecular precursors

Quadrilateral CdO nanoparticles were grown from cadmium cupferronate complex by injecting the precursor dissolved in octylamine into trioctylamine at 220 and 250 degrees C. CdO/ZnO core/shell structures were synthesized with a method similar to that of growing CdO cores by injecting the shell precursor following the growth of cores. The shell growth temperature was adjusted from 160 to 130 degrees C, and the shell precursor supply speed was adjusted from 4 to 8 ml/h. The obtained nanostructures were characterized by X-ray diffraction, high resolution transmission electron microscope, and ultraviolet-visible spectrophotometer. No core/shell structures formed if the shell precursor injection speed was as high as 8 ml/h. A very thin layer of ZnO shells would form on CdO cores if the shell precursor was injected at a speed of 4 ml/h at temperature of 160 degrees C, and the shells had good crystal quality. CdO/ZnO core/shell nanostructures were inclined to be spherical, and no homogeneous formation of ZnO nanoparticles was observed if the shell precursor injection temperature was lowered to 130 degrees C.

Aerobic power assessment by using a 10 min heart rate control running on treadmill

AIM

This study evaluated the reliability and validity of a proposed 10 min running speed variance test (RSVHRC) in assessing aerobic power at which the intensity was controlled at 80% of age-predicted maximal heart rate (HR).

METHODS

Forty-four college students (21 men and 23 women, age: 21+/-3 years, height: 166.6+/-7.9 cm, weight: 61.7+/-9.3 kg) were recruited to undergo 2 RSVHRC test trials, and a maximal exercise test at least 24 hours apart. The test consisted of a 3-min warm-up at 1.67 km/h, followed by adjusting speed up to either at 2.5 m/s or 2.78 m/s immediately depending upon onset HR after the warm-up. HR was monitored every 30 seconds and running speed was adjusted accordingly to maintain HR (+/-5bpm) for 10 minutes. RSVHRC was determined by the slope of distance/time relationship from 3rd to 10th min.

RESULTS

Pair t-test showed that there was no significant difference between 1st (2.38+/-0.58 m/s) and 2nd trial (2.40+/-0.63 m/s). Intraclass correlation coefficient (ICC) score showed that RSVHRC was highly reliable (ICC=0.98, 95% CI=0.97-0.99). Coefficient of variation, standard error of measurement (SEM), and %SEM were 4.8%, 0.12 m/s, 5.02% respectively. Additionally, a Pearson product-moment correlation coefficient demonstrated 2 trials were correlated with maximal oxygen uptake (46.6+/-8.1 mL/kg/min) at r=0.74, 0.71 (P<0.05).

CONCLUSION

In conclusion, 80%HRmax RSVHRC is an easy and highly reliable submaximal exercise test that provides good validity to assess aerobic power in young and healthy population, which can be applied on treadmill setting.

[Influence of carbon monoxide on the expression of inducible nitric oxide synthase mRNA in guinea pigs with allergic rhinitis.]

OBJECTIVE

To study the impact of carbon monoxide (CO) on expression levels of inducible nitric oxide synthase (iNOS) mRNA in guinea pigs with allergic rhinitis (AR).

METHODS

Twenty four guinea pigs were divided randomly into four study groups with 6 guinea pigs in each. The guinea pigs in the first group were treated with saline only (Group 1, the healthy controls). The remaing guinea pigs were sensitized by ovalbumin and thus establishing the AR models. After sensitization, the animals in the second group remained untreated (Group 2, AR control group). The third group was treated with Hemin as the induction group, and the fourth group was treated with Zinc protoporphyrin (ZnPP) as the suppression group. The plasma concentration of carboxyhemoglobin (COHb) was measured, which represents the concentration of CO. The expression levels of Heme oxygenase-1 (HO-1) and NOS mRNAs in nasal mucosa were determined by fluorescent quantitative RT-PCR.

RESULTS

AR models were established successfully in all study guinea pigs. The concentrations of COHb (x(-) +/- s) in plasma of the second group (2.27% +/- 1.13%) were significantly (q = 4.10, P < 0.01) higher than those of healthy controls (1.08% +/- 0.24%). The plasma concentration of COHb in the third group (3.17% +/- 0.68%) were also significantly higher (q = 3.12, P < 0.05) than those in the second group. The expression levels of HO-1 and iNOS in nasal mucosa of the second group [(7.80 +/- 1.60) x 10(-3) and (5.81 +/- 0.05) x 10(-3), respectively] were also significantly (q equals 5.52 and 7.21, respectively, P < 0.01) higher than those of controls [(1.96 +/- 0.71) x 10(-3) and (0.97 +/- 0.05) x 10(-3), respectively]. The expression levels of HO-1 and iNOS in the nasal mucosa of the third group [(11.89 +/- 4.78) x 10(-3) and (7.42 +/- 0.70) x 10(-3), respectively] were significantly (q equals 3.86 and 2.22, P < 0.05) higher than those of the second group. The expression levels of HO-1 and iNOS in nasal mucosa of the fourth group [(3.82 +/- 0.98) x 10(-3) and (2.34 +/- 0.04) x 10(-3), respectively] were significantly (q equals 3.76 and 5.18, P < 0.05) lower than those in the second group.

CONCLUSIONS

Endogenous carbon monoxide influenced the expression levels of iNOS in nasal mocusa in guinea pigs with AR.

Enhanced 2.0 microm emission and gain coefficient of transparent glass ceramic containing BaF2: Ho3+,Tm3+ nanocrystals

Transparent glass ceramic containing BaF(2):Ho(3+),Tm(3+) nanocrystals has been prepared by melt quenching and subsequent thermal treatment. The precipitation of BaF(2) nanocrystals was confirmed by X-ray diffraction and high-resolution transmission electron microscopy. Intense 2.0 microm fluorescence originating from Ho(3+): (5)I(7) --> (5)I(8) transition was achieved upon excitation with 808 nm laser diode. A large ratio of forward Tm(3+) --> Ho(3+) energy transfer constant to that of backward process indicated high efficient energy transfer from Tm(3+)((3)F(4)) to Ho(3+)((5)I(7)), benefited from the reduced ionic distances of Tm(3+)-Tm(3+) and Tm(3+)-Ho(3+) pairs and low phonon energy environment with the incorporation of rare-earth ions into the precipitated BaF(2) nanocrystals. The results indicate that glass ceramic is a promising candidate material for 2.0 microm laser.

Characterization and expression of a myosin heavy-chain isoform in juvenile walleye Sander vitreus

In this study, myosin, the major component of myofibrillar protein in the skeletal muscle, was characterized and its expression was monitored during growth in juvenile walleye Sander vitreus. First, the coding region of myosin heavy chain (MyHC) from the fast skeletal muscle of walleye was amplified by long-distance PCR using a full-length cDNA. Phylogenetic analysis was used to determine the evolutionary relationship of this S. vitreus myosin sequence to other vertebrate myosin sequences. Next, it was established that the myosin isoform was most prevalent in the white muscle, compared with the red and cardiac muscle. Myosin expression was monitored over a series of experiments designed to influence growth. Specifically, change in MyHC mRNA was monitored after acute changes in feeding. Fish exposed to a one-week fasting period showed significant decreases in MyHC mRNA levels by the end of the fast. The effect of feeding was also examined more closely over a 24 h period after feeding, but results showed no significant change in myosin expression levels through this time period. Finally, fish with higher growth rates had higher MyHC mRNA and protein expression levels. This study indicates that MyHC mRNA expression is sensitive to the factors that may influence growth in juvenile S. vitreus.

Interaction of polybrominated diphenyl ethers (PBDEs) with anaerobic mixed bacterial cultures isolated from river sediment

The degradation of flame retardant polybrominated diphenyl ethers (PBDE), including tetra-brominated diphenyl ether (BDE-47), penta-brominated diphenyl ether (BDE-99 and -100), and hexa-brominated diphenyl ether (BDE-153 and -154), by anaerobic bacterial mixed cultures isolated from river sediment was investigated. The effects of PBDEs on changes of anaerobic bacterial community in sediment culture were also studied. Sediments were collected from Er-Jen River and Nan-Kan River basins, which were both heavily polluted rivers in Taiwan, and bacteria from the sediment samples were enriched before the experiment was conducted. Into the anaerobic bacterial mixed cultures, 0.1 microg/mL of PBDEs was added followed by incubation under 30 degrees C for 70 days. Residues of PBDE were determined by gas chromatography with electron capture detector (GC-ECD), and the changes of bacterial community were analyzed by denaturing gradient gel electrophoresis (DGGE). Less than 20% of PBDEs were degraded after 70 days of incubation in all samples except for BDE-47 from the Nan-Kan River sediment. In that culture, BDE-47 was found to have notably degraded. In particular, after 42 days of incubation; BDE-47 was degraded, suddenly and sharply, to a negligible level on Day 70, and the result was confirmed by a repeated experiment. An interesting result was that although BDE-47 was degraded fast in the Nan-Kan River sediment, the bacterial communities did not shift significantly as we had speculated at Day 70. From UPGMA dendrograms, PBDEs changed the composition of bacterial communities, and the extents varied with the variety of PBDE congeners. By the amendment with BDE-153 or -154, bacterial communities would be changed immediately and irreversibly throughout the rest of the incubation period. No significant difference in degradation of PBDEs was observed between sediment bacteria from Er-Jen River and Nan-Kan River. However, the results verified the persistence of PBDEs in the environment.

Exposure to low concentrations of dissolved ammonia promotes growth rate in walleye Sander vitreus

The objective of the current study was to examine whether sublethal (moderate) levels of dissolved ammonia may be beneficial to growth in juvenile walleye Sander vitreus (recent evidence in juvenile rainbow trout Oncorhynchus mykiss has shown significant increases in protein synthesis in the presence of moderately elevated concentrations of dissolved ammonia). Moderately elevated dissolved ammonia concentrations between 100 and 300 micromol l(-1) suppressed routine aerobic metabolic activity by 20% during acute trials (2 h), while promoting specific growth rate (>50%) and elevating whole body soluble protein content by 20% in the early stages (14-42 days) in chronic ammonia exposure experiments. Juvenile S. vitreus held at ammonia concentrations between 107.6 +/- 5.5 and 225.5 +/- 4.7 micromol l(-1) (mean +/-s.e.) grew significantly faster than control fish and significantly reduced plasma cortisol levels (<3 microg dl(-1)). Results from this study suggest that chronic exposure to moderate amounts of dissolved ammonia significantly increase growth rates in juvenile S. vitreus by increasing nitrogen accessible for supplementary protein deposition leading to somatic development.

Clinical pathology of perineural invasion in hilar cholangiocarcinoma

AIM: To elucidate the characteristics and mechanism of perineural invasion in hilar cholangiocarcinoma.

METHODS: A clinicopathologic study was conducted on tissue sections from 73 patients with hilar cholangiocarcinoma to observe the incidence and modes of perineural invasion. Clinicopathologic factors, such as tumor differentiation and pathologic stage, were analyzed when perineural invasion was observed in the sections. Immunohistochemical staining for CD34 and D2-40 in cancer tissue samples was performed to clarify the association of perineural invasion with vessels.

RESULTS: The overall incidence of perineural invasion was 91.78% (67 of 73 patients). However, the incidence of perineural invasion did not show any remarkable difference in various differentiated adenocarcinomas. Logistic regression analysis identified that penetration of bile duct was significantly correlated with perineural invasion (P < 0.01). The microvessel density (MVD) was significantly lower in well-differentiated adenocarcinomas than in moderately- and poorly- differentiated adenocarcinomas (P < 0.05). Five patterns were observed as the tumor cells invaded nerve fibers. Although tumor cells were found to invade microvessels and microlymphatics, immunohistochemical staining for CD34 and D2-40 respectively showed no association between perineural invasion and lymphatic or vascular invasion.

CONCLUSION: Perineural invasion is common in hilar cholangiocarcinoma and does not develop via the lymphatic or vascular network, but is a continuous extension from the primary tumor. Nerve plexus around the membrana adventitia should be completely divested during radical excision of hilar cholangiocarcinoma.

Comparison of four infectious bursal disease viruses isolated from different bird species

Four isolates of infectious bursal disease virus (IBDV), isolated from chicken, duck, goose and sparrow in Jiangsu province of China in 2002, were compared. The viruses were stable to the treatments of 60 degrees C for 1 h, pH 2.0 and lipid solvents. Their antigenic relatedness values (R) were from 0.76 to 0.78. Chickens infected with the chicken isolate showed severe clinical symptoms of IBD and the mortality rate was 33.3% (2/6). Chickens infected with the other three viruses survived but their bursas were damaged and the bursa/body-weight ratios were lower than those of the uninfected control (p< 0.01). The titers of anti-IBDV antibody in infected chicken sera reached up to 1600 by virus neutralization and 6400 by ELISA at 10 days post infection. The sequences of the variable region of VP2 were aligned and compared, showing nucleotide variations ranging from 1.5 to 6.7% and deduced aminoacid variations from 0.8 to 2.2%. All had the same heptapeptide, S-W-S-A-S-G-S, Asp279, and Ala284. The four viruses clustered on a phylogenetic tree and were distant from the STC strain. These findings suggested that different bird species naturally infected with IBDV could serve as carriers or reservoirs in IBDV transmission and might play a role in the emergence of variant IBDV.

[Treatment of the windblow hand deformity]

OBJECTIVE

To discuss the treatment of the windblow hand deformity.

METHODS

We treat 18 patients with operations step by step. First phase: to improve the thumb function; Second phase: shift the flexor digitorum superficialis of the middle and little finger to improve the ulnar drift of the digits; Third phase : to solve the flection deformity of the palm and digits.

RESULTS

We follow the patients for 6 - 72 months, only lost 3.11 of 15 patients have the thumb function recovered. 9 patients had their ulnar drift of the digits corrected, 2 patients partly corrected, 4 have relapse. 5 among the 15 patients were offered second operation, to have the ulnar arthrosis bursa contracted, using abduction splint, after rehabilitation 4 patients have the deformity corrected, 1 has partly corrected.

CONCLUSIONS

Operation step by step is better for the complex windblow hand deformity, solve one major problem each time,and systemic rehabilitation therapy is needed for satisfied curative effect.

Comprehensive study of lead pollution in Shanghai by multiple techniques

Aerosol samples of PM10 particulates were examined with particle-induced X-ray emission (PIXE and micro-PIXE ), inductively coupled plasma-mass spectrometry, and X-ray absorption fine structures (XAFS) to investigate atmospheric Pb concentrations and its chemical species and to decide the source assignment. From the elemental analyses, lead concentrations were averaged at 369 and 237 ng.m-3 in aerosol samples of PM10 collected from 19 monitor sites in Shanghai in the winter of 2002 and 2003, respectively. The XAFS results show that major chemical forms of the lead particulates are probably PbCl2, PbSO4, and PbO. A calculation of isotope ratio and chemical mass balance of the PM10 samples revealed that the atmospheric lead particulates in Shanghai in the two periods were mainly from coal combustors, iron and steel plants, and automobile exhausts, with coal combustion dominating the lead pollution after the phasing out of leaded gasoline in 1997 in Shanghai.

Metabolic and ionoregulatory responses of the Amazonian cichlid, Astronotus ocellatus, to severe hypoxia

We examined the metabolic and ionoregulatory responses of the Amazonian cichlid, Astronotus ocellatus, to 20 h exposure to severe hypoxia (0.37 +/- 0.19 mg O(2)/l; 4.6% air saturation) or 8 h severe hypoxia followed by 12 h recovery in normoxic water. During 20 h exposure to hypoxia, white muscle [ATP] was maintained at normoxic levels primarily through a 20% decrease in [creatine phosphate] (CrP) and an activation of glycolysis yielding lactate accumulation. Muscle lactate accumulation maintained cytoplasmic redox state ([NAD(+)]/[NADH]) and was associated with an inactivation of the mitochondrial enzyme pyruvate dehydrogenase (PDH). The inactivation of PDH was not associated with significant changes in cytoplasmic allosteric modulators ([ADP(free)], redox state, or [pyruvate]). Hypoxia exposure caused an approximately 65% decrease in gill Na(+)/K(+) ATPase activity, which was not matched by changes in Na(+)/K(+) ATPase alpha-subunit protein abundance indicating post-translational modification of Na(+)/K(+) ATPase was responsible for the decrease in activity. Despite decreases in gill Na(+)/K(+) ATPase activity, plasma [Na(+)] increased, but this increase was possibly due to a significant hemoconcentration and fluid shift out of the extracellular space. Hypoxia caused an increase in Na(+)/K(+) ATPase alpha-subunit mRNA abundance pointing to either reduced mRNA degradation during exposure to hypoxia or enhanced expression of Na(+)/K(+) ATPase alpha-subunit relative to other genes.

Optical Properties of ZnO Nanocrystals Doped with Cd, Mg, Mn, and Fe Ions

ZnO nanocrystals doped with Cd, Mg, Mn, and Fe ions were obtained by thermolysis of a family of metal cupferrates. The nanocrystals were characterized by X-ray diffraction, energy-dispersive X-ray analysis, transmission electron microscopy, UV-visible, luminescence, and excitation spectroscopy. The band gap of the nanocrystals can be tuned in the range of 2.9-3.8 eV by the use of the dopants. In most cases, the nanocrystals are sufficiently defect-free to exhibit band edge luminescence.

Nanocrystalline ZnO with Ultraviolet Luminescence

Octylamine capped ZnO nanoparticles with mean diameters in the range of 4-14 nm were obtained by thermolysis of single source metal-organic precursors. The nanocrystals were characterized by X-ray diffraction, transmission electron microscopy, and UV-visible, luminescence, and excitation spectroscopies. The nanocrystals are sufficiently defect-free to exhibit band edge luminescence. The size dependence of the changes in the band gap have been calculated by different methods and compared with the Kayanuma model.

The pre-styloid compartment of the parapharyngeal space: a three-dimensional digitized model based on the Chinese Visible Human

To build a digitized visible model of the parapharyngeal space of the Chinese Visible Human and to provide a sectional anatomic basis for radiological and clinical diagnosis of the parapharyngeal space, sectional anatomy data of the parapharyngeal space were selected from the Chinese Visible Human male and female to compare with MR imaging findings in the axial planes. From these data the parapharyngeal space and surrounding structures were segmented. They were then reconstructed in three dimensions on PC. In the axial planes of the sectional anatomy and MR imaging, the shape, content and relations of the parapharyngeal space were clearly displayed and the dominant plane for showing the parapharyngeal space was elicited. The three-dimensional reconstructed images displayed perfectly the anatomic relationships of the parapharyngeal space, parotid, muscles, mandible and vessels. All reconstructed structures can be displayed singly, in groups or as a whole; any diameter or angle of the reconstructed structures can be easily measured. The Chinese Visible Human male and female data set can provide complete and accurate data. The digitized model of the parapharyngeal space and its surroundings offers unique insights into the complex anatomy of the area, providing morphologic data for imaging diagnosis and surgery of the parapharyngeal space.

Solution structure and backbone dynamics of an engineered arginine-rich subdomain 2 of the hepatitis C virus NS3 RNA helicase

The NS3 protein of the hepatitis C virus (HCV) is a 631 amino acid residue bifunctional enzyme with a serine protease localized to the N-terminal 181 residues and an RNA helicase located in the C-terminal 450 residues. The HCV NS3 RNA helicase consists of three well-defined subdomains which all contribute to its helicase activity. The second subdomain of the HCV helicase is flexibly linked to the remainder of the NS3 protein and could undergo rigid-body movements during the unwinding of double-stranded RNA. It also contains several motifs that are implicated in RNA binding and in coupling NTP hydrolysis to nucleic acid unwinding and translocation. As part of our efforts to use NMR techniques to assist in deciphering the enzyme's structure-function relationships and developing specific small molecule inhibitors, we have determined the solution structure of an engineered subdomain 2 of the NS3 RNA helicase of HCV, d(2Delta)-HCVh, and studied the backbone dynamics of this protein by (15)N-relaxation experiments using a model-free approach. The NMR studies on this 142-residue construct reveal that overall subdomain 2 of the HCV helicase is globular and well structured in solution even in the absence of the remaining parts of the NS3 protein. Its solution structure is very similar to the corresponding parts in the X-ray structures of the HCV NS3 helicase domain and intact bifunctional HCV NS3 protein. Slow hydrogen-deuterium exchange rates map to a well-structured, stable hydrophobic core region away from the subdomain interfaces. In contrast, the regions facing the subdomain interfaces in the HCV NS3 helicase domain are less well structured in d(2Delta)-HCVh, show fast hydrogen-deuterium exchange rates, and the analysis of the dynamic properties of d(2Delta)-HCVh reveals that these regions of the protein show distinct dynamical features. In particular, residues in motif V, which may be involved in transducing allosteric effects of nucleotide binding and hydrolysis on RNA binding, exhibit slow conformational exchange on the milli- to microsecond time-scale. The intrinsic conformational flexibility of this loop region may facilitate conformational changes required for helicase function.

Carbon dioxide flux density in cultivated rice paddy field

The carbon dioxide flux density in a subtropical cultivated rice paddy field were determined over four crop seasons (two consecutive years) at five stages of rice plant development, transplanting, active tillering, booting, flowering and ripening, and an idle period between crops. During 24 h sampling periods at those stages, the CO2 flux densities were measured and found to be -2,000 to 55,000 mg CO2/m2/day in the first year and 600 to 29,000 mg CO2/m2/day in the second year in acrylic chambers covering rice plants. The CO2 flux densities in glass domes without plants but with soil were -700 to 6,000 mg CO2/m2/day in the first year and 147 to 4,500 mg CO2/m2/day in the second year. The data for the CO2 flux density over an entire year are extrapolated. Although our non-controlled environment experiments have inherent drawbacks, the collected data indicate that continuous rice cultivation has a tendency to result in increased CO2 emissions.

Correlation of gas chromatographic properties of chlorobenzenes and polychlorinated biphenyls with the occurrence of reductive dechlorination by untamed microorganisms

To understand the dechlorination ability of chlorobenzenes (CBs) and polychlorinated biphenyls (PCBs) by untamed microorganisms under anaerobic condition and to correlate gas chromatographic properties with the occurrence of reductive dechlorination, introduction of CBs and PCBs in the culture medium inoculated with microorganisms from sludge and sediment, respectively, were performed. Three kinds of culture media preparing from sludge, river water and a synthetic medium were used in the experiments. HCB was degraded to 1,3,5-trichlorobenzene (1,3,5-TCB) and 1,3-dichlorobenzene (1,3-DCB) in both sludge medium and synthetic medium with inoculated microorganisms. Three PCB congeners including 2,3,4-, 3,4,5- and 2,3,4,5-CBp (chlorinated biphenyl) were not found to be dechlorinated in the river water medium with inoculation culture but to be dechlorinated in the synthetic medium. MNDO methodology was used to compute theoretical dechlorination reaction heats and GC-ECD techniques were used to estimate chromatographic data of CB and PCB congeners. Both CB and PCB congeners showed that dechlorination by untamed microorganisms under anaerobic mixed cultures were more likely to occur when larger amounts of energy were released and greater deltaln RRT value between the parent congener and the daughter product was observed. Deltaln RRT provided a more precise information on the singularity of PCBs ortho-dechlorination in an aspect of thermodynamic favorable rule.

Down-regulation of Fas-L in glioma cells by ribozyme reduces cell apoptosis, tumour-infiltrating cells, and liver damage but accelerates tumour formation in nude mice

Fas-L (CD95L, APO-1L) expresses in a variety of tumours and has been proposed to play a role in tumour formation and metastasis. The contribution of Fas-L to tumour growth, however, is not conclusive especially in systems using cells with over-expressed Fas-L. In this study we down-regulated the expression o Fas-L in human glioma cells by a hammerhead ribozyme (Fas-L(ribozyme)) targeting against Fas-L mRNA. Fas-L(ribozyme)-carrying cells exhibited slightly enhanced growth rate and less degree of spontaneous apoptosis in vitro as compared with vector controls. In nude mice, Fas-L(ribozyme)-carrying cells grew faster with lesser apoptosis, formed bigger tumour with significantly fewer infiltrating cells in the tumour area, and triggered relatively milder tumour-associated liver damage than vector controls did. Thus, down-regulation of Fas-L not only improved viability of glioma cells but also reduces local immune responses that may consequently affect tumour formation. Taken together, our findings imply that endogenous expression of Fas-L in malignant cells is not always growth promoting.

Design, high-level expression, purification and characterization of soluble fragments of the hepatitis C virus NS3 RNA helicase suitable for NMR-based drug discovery methods and mechanistic studies

RNA helicases represent a family of enzymes that unwind double-stranded (ds) RNA in a nucleoside triphosphate (NTP)-dependent fashion and which are required in all aspects of cellular RNA metabolism and processing. The hepatitis C virus (HCV) non-structural 3 (NS3) protein possesses a serine protease activity in the N-terminal one-third, whereas RNA-stimulated NTPase and helicase activities reside in the C-terminal portion of the 631 amino acid residue bifunctional enzyme. The HCV NS3 RNA helicase is of key importance in the life cycle of HCV, which makes it a target for the development of therapeutics. However, neither the precise mechanism nor the substrate structure has been defined for this enzyme. For nuclear magnetic resonance (NMR)-based drug discovery methods and for mechanistic studies we engineered, prepared and characterized various truncated constructs of the 451-residue HCV NS3 RNA helicase. Our goal was to produce smaller fragments of the enzyme, which would be amenable to solution NMR techniques while retaining their native NTP and/or nucleic acid binding sites. Solution conditions were optimized to obtain high-quality heteronuclear NMR spectra of nitrogen-15 isotope-labeled constructs, which are typical of well-folded monomeric proteins. Moreover, NMR binding studies and functional data directly support the correct folding of these fragments.

The kinetics and thermodynamics of surfactants in solvent sublation

Solvent sublation has been performed on very dilute solutions of one cationic surfactant, hexadecylpyridinium chloride (HPC), and one anionic surfactant, dodecylbenzenesulfonic acid (LBS). Some thermodynamic values were obtained, e.g. molecular areas, A0, which are 50.0 and 47.7 A2/molecule, respectively, for HPC and LBS, and free adsorption energies, delta G(o)ads, which are -33.17 and -43.58 kJ mol(-1), respectively, for HPC and LBS. The kinetics were determined for a range of temperatures and gas flow-rates. Although the processes of solvent sublation of the two surfactants obey first-order kinetics, the respective adsorption mechanisms of HPC and LBS in the solvent sublation process were different. The pH and the presence of KCl and ethanol had no effect on the solvent sublation of LBS. The apparent active energy was calculated as 8.11 kJ mol(-1).

Monoclonal antibodies against human ribosomal P proteins penetrate into living cells and cause apoptosis of Jurkat T cells in culture

OBJECTIVE

This study was designed to determine the role of autoantibodies to the ribosomal P protein (anti-P Abs) in the pathogenesis of systemic lupus erythematosus (SLE) using monoclonal anti-P antibodies (anti-P mAbs).

METHODS

Anti-P mAbs were prepared by a standard hybridoma procedure using recombinant human P1 and P2 proteins as immunogens. We studied the reactivities of these mAbs to P proteins, their binding and penetration capabilities in different cell lines and their apoptotic effects on Jurkat T cells.

RESULTS

In addition to recognizing human P0, P1 and P2 proteins, the anti-P mAb 9B6-4 bound to 20-40% and penetrated 50-90% of astrocytes, Jurkat T cells and lung cancer cells via the P0 surface protein. Treatment with the mAb 9B6-4 also caused increases in the percentages of Jurkat T cells in the sub-G1 phase of the cell cycle (14.8%) and undergoing apoptosis (21.3%).

CONCLUSION

Anti-P autoantibodies may play a role in the pathogenesis of lymphopenia or lymphocyte dysfunction in SLE.

Environmental dissipation of fungicide triphenyltin acetate and its potential as a groundwater contaminant

The effects of various factors on fungicide triphenyltin acetate dissipation in selected soil types were studied; temperature is clearly the most important factor of these. Residues of this fungicide in Fangtzupo clay loam and Lanyang loam incubated at 30 degrees C for 32 days (water content 100, 70, or 40% of field capacity) were 25% of the original amounts. In soil samples incubated at 10, 30, or 40 degrees C with 100% field capacity water content, residues were 80, 26, and 5.5% for Fangtzupo soil, respectively, and 83, 26, and 7.0% for Lanyang soil, respectively. No significant difference in dissipation rate was found between sterilized and unsterilized soil, suggesting that microbial degradation is not an important factor in this process. Rapid degradation rates were observed-half-lives of 8.3 to 19.4 days in Fangtzupo clay loam and 8.0 to 16.3 days in Lanyang loam at temperatures ranging from 30 to 40 degrees C (soil water content of 100, 70, and 40% of field capacity). Significant increases in half-life (approximately 150 days) occurred at lower temperatures (10 degrees C) in both soil types. The potential of triphenyltin acetate to contaminate groundwater was tested using the behavior assessment and groundwater pollution-potential models. Results indicate that the leaching rate of the fungicide is very slow (1.0 cm day(-1)) under normal conditions.

Application of microbial enumeration technique to evaluate the occurrence of natural bioremediation

Natural bioremediation is believed to be the major processes that account for both containment of the petroleum-hydrocarbon plume and reduction of the contaminant concentrations. In this study, the feasibility of applying the microbial enumeration technique was assessed for natural biodegradation evaluation at three selected gasoline spill sites. At each site, two monitor wells were installed along the groundwater flow, and one multilevel sampler (MLS) was installed to delineate the vertical distribution of the contaminant plume. Two continuous soil cores were collected at each site to evaluate the horizontal distribution of the microbial activity. Soil samples were used for microbial enumeration, grain-size distribution analysis, and sediment extraction. In situ tracer study was performed using 1,2,4-trimethylbenzene (1,2,4-TMB) as the tracer to study the efficiency of contaminant biodegradation. Investigation results demonstrate the agreement between microbial enumeration and other evaluation techniques for natural bioremediation (e.g., geochemical indicator analysis, tracer study). Results suggest that the microbial enumeration is useful in assessing the occurrence, efficiency, and status of the bioremediation. Because this technique provides insight into factors controlling contaminant biodegradation, it could be performed as the supplemental method for natural bioremediation evaluation at petroleum-hydrocarbon spill sites.

[Experimental study on the hemostatic properties of collagen sponge]

OBJECTIVE

To validate the hemostatic properties of collagen sponge made in China.

METHODS

The experimental model of superficial cut of liver was established in 20 Sprague-Dawley adult rats, which were divided into two groups randomly. Collagen sponge or gelatin sponge was used to cover the cut respectively. Hemostatic result was observed. Afterwards, standard liver trauma model by resection left front liver lobe was made, wound was treated with collagen sponge or gelatin sponge respectively. Hemostatic result was observed. Concurrent hemostatic time and bleeding amount were noted. At 7, 14 and 20 days after operation, intra-abdominal adhension, infection and healing state of liver were observed by exploratory laparotomy. The histological changes of regenerate liver tissue were observed by microscopy.

RESULTS

Collagen sponge adhered to wound well. Concurrent hemostatic time and bleeding amount in collagen sponge group were superior to those of gelatin sponge (P < 0.05). The histological examination showed that collagen sponge was absorbed and degraded rapidly, regenerative hepatocytes could be induced.

CONCLUSION

Collagen sponge has fine hemostatic properties and can induce regeneration of hepatocytes effectively. It is worth popularizing for its convenience in clinical application and its properties of rapid degradation and absorption.

Comparisons of PCBs dechlorination occurrences in various contaminated sediments

A comparison was made of reductive dechlorination occurrences of polychlorinated biphenyls (PCBs) by microorganisms collected from contaminated sediments including Er-Jen River (Tainan, Taiwan), Hudson River (Ft. Edward, NY), Silver Lake (Pittsfield, MA) and Puget Sound (Washington State). Comparisons was made in terms of chromatographic data (referring to the biological activity, including microbial availability) and thermodynamic data (demonstrating the selectivity of anaerobic microorganisms in the dechlorination of chlorinated compounds). Chromatographic data was established in terms of difference in relative retention time (delta ln RRT) and thermodynamic data was estimated as heat of reaction (delta H(r)0). Both were calculated and correlated to occurrences of dechlorination reactions. Observed dechlorination reactions for individually introducing PCB congener had delta ln RRT levels measured as >0.47 (Er-Jen River), >0.29 (Hudson River), >0.36 (Silver Lake) and >0.45 (Puget Sound, for Aroclor 1254 dechlorination). Critical of delta H(r)0 and delta ln RRT values showed that Hudson River and Silver Lake microorganisms were capable of dechlorinating PCBs through reactions with larger H(r)0 value (lower levels of released energy) and smaller delta ln RRT value compared with those found in Er-Jen River and Puget Sound sediments. Differences in the critical delta ln RRT values of these sediments may be due to differences in their levels of PCB contamination.

Leo Eloesser: an American cardiothoracic surgeon in China

We present a brief historical vignette about one of the pioneer cardiothoracic surgeons, Leo Eloesser, from our personal recollections and descriptions of part of his long life that was spent in China. Although this article deals mainly with his time in China during his close association with the senior author, Dr Eloesser is certainly one of the most extraordinary surgeons of the 20th century.

Preclinical evaluation of locoregional delivery of radiolabeled iododeoxyuridine and thymidylate synthase inhibitor in a hepatoma model

We report improved incorporation of the radiolabeled-thymidine analog [125I/131I]5-iodo-2'-deoxyuridine ([125I/131I]IdUrd) into DNA by the addition of Thymitaq, a thymidylate synthase inhibitor, as a strategy of molecular radiotherapy for hepatoma treatment.

METHODS

The synergistic effect of combination [125I]IdUrd and Thymitaq in clonogenic survival and DNA incorporation was shown on the human hepatoma cell line Hep3B. Radiobiodistribution of intrahepatic arterially injected [125I]IdUrd and Thymitaq was studied in a rat N1S1 hepatoma model. In vivo therapeutic effects of locoregional delivery of both drugs were evaluated in mouse subcutaneous hepatoma and ascitic hepatoma models.

RESULTS

In a clonogenic assay, Thymitaq showed a synergistic effect with [125I]IdUrd but not cold IdUrd. Thymitaq had a dose-dependent modulation effect on DNA-[125I]IdUrd incorporation. The biodistribution study indicated a slower clearance rate of [125I]IdUdR in the hepatoma as well as an initially higher uptake of [125I]IdUrd into DNA when the [125I]IdUrd was combined with Thymitaq. In vivo studies showed a superior therapeutic effect of combination Thymitaq and [125I]IdUrd in both subcutaneous and ascites tumor models, but the combination of [131I]IdUrd and [125I]IdUrd may be more effective than Auger electron emitters alone for the treatment of subcutaneous tumor.

CONCLUSION

The strategy of locoregional delivery of [125I/131I]IdUrd to a tumor site through an intrahepatic arterial, intratumoral, or intraperitoneal route in combination with Thymitaq is promising and may also have a favorable therapeutic index in vivo.

[Methodological studies on quantitative determination of beta-eudesmol in Atractylodes lancea (thunb.) DC]

OBJECTIVE

To establish methodologically a method for quantitative determination of beta-eudesmol in Atractylodes lancea.

METHOD

GC, column: 3 mm x 2 m; stationary phase; 15% QF-1; support: Chromosorb WAW(60-80 mesh); detector: hydrogen flame ionization detector; injection chamber temperature: 210 degrees C; column temperature: 174 degrees C; carrier gas: N2:50 ml.min-1, air: 49 kPa, H2:58.8 kPa; sensibility range: 10(2) x 64; chart speed: 2.5 mm.min-1.

RESULT

Average recovery ratio is 100.7% (n = 5).

CONCLUSION

This method can be used to control the quality of A. lancea.

The HIV glycoproteins gp41 and gp120 cause rapid excitation in rat cortical slices

Inflammation and associated excitotoxicity may play important roles in various neurodegenerative diseases including AIDS dementia. Here we show that exposure of rat parietal cortical slices to the HIV glycoproteins gp120 and gp41 triggered very rapid releases of the neurotransmitters glutamate and [(3)H]noradrenaline (NA), and of the neuromodulator adenosine. Gp41 was more effective than gp120 at releasing glutamate and [(3)H]NA, while both glycoproteins were equi-effective at releasing adenosine. The responses to gp120 and gp41 declined rapidly to basal levels following their removal. It seems possible that rapid, inappropriate excitation may occur in the immediate vicinity of HIV infections in the brain, possibly producing some of the transient neurological and psychiatric symptoms associated with AIDS dementia.

Identification of the major positional isomer of pegylated interferon alpha-2b

Interferons display a wide range of antiviral, antiproliferative, and immunomodulatory activities on a variety of cell types and have been used to treat many diseases including hairy-cell leukemia and hepatitis B and C and have also been applied to other therapeutic areas. To improve the pharmacological properties of interferon (IFN) alpha-2b, a long-acting pegylated form (PEG-IFN) has been developed [PEG, monomethoxy poly(ethylene glycol) with average molecular mass of 12 000 Da]. PEG-IFN is a mixture of pegylated proteins with differing sites of PEG attachment. To identify the major positional isomer in the pegylated material [PEG-IFN(His-34)], NMR studies were conducted on a subtilisin-digested N-acetylated peptide of the major positional isomer [PEG-IFN(His-34)dig], synthetic peptide analogues containing His-34, as well as unmodified IFN and PEG-IFN(His-34). Our studies reveal a novel interferon-polymer attachment site as a histidine-linked interferon conjugate. We show that the major component of PEG-IFN is pegylated in the imidazole side chain of histidine-34. Chemical shift data suggest that pegylation occurs mainly at the N(delta)(1) position in the imidazole side chain of this residue. This positional isomer, PEG-IFN(His-34), comprises approximately 47% of the total pegylated species when PEG-IFN is synthesized under the current experimental conditions at pH 6.5 with an electrophilic derivative of PEG, succinimidyl carbonate PEG. The reversibility of the histidine modification was examined. The PEG-imidazole adduct in the intact protein, PEG-IFN(His-34), is labile but much more stable than in the peptide, PEG-IFN(His-34)dig. Apparently, the tertiary structure of the intact protein protects the His(34)-imidazole ring from depegylation.

Molecular characterization of a urea transporter in the gill of the gulf toadfish (Opsanus beta)

Urea excretion by the gulf toadfish (Opsanus beta) has been shown in previous studies to be a highly pulsatile facilitated transport, with excretion probably occurring at the gill. The present study reports the isolation of an 1800 base pair (kb) cDNA from toadfish gill with one open reading frame putatively encoding a 475-residue protein, the toadfish urea transporter (tUT). tUT, the first teleostean urea transporter cloned, has high homology with UTs (facilitated urea transporters) cloned from mammals, an amphibian and a shark, and most closely resembles the UT-A subfamily. When expressed in Xenopus laevis oocytes, tUT increased urea permeability (as measured by [(14)C]urea uptake) five- to sevenfold, and this permeability increase was abolished by phloretin, a common inhibitor of other UTs. Northern analysis using the 1.8 kb clone was performed to determine the tissue distribution and dynamics of tUT mRNA expression. Of six tissues examined (gill, liver, red blood cells, kidney, skin and intestine), only gill showed expression of tUT mRNA, with a predominant band at 1.8 kb and a minor band at 3.5 kb. During several points in the urea pulse cycle of toadfish (0, 4, 6, 12 and 18 h post-pulse), measured by excretion of [(14)C]urea into the water, gill mRNA samples were obtained. Expression of tUT mRNA was found to be largely invariant relative to expression of beta-actin mRNA over the pulse cycle. These results further confirm the gill localization of urea transport in the toadfish and suggest that tUT regulation (and the regulation of pulsatile urea excretion) is probably not at the level of mRNA control. The results are discussed in the context of the mechanisms of vasopressin-regulated UT-A in mammalian kidney and morphological data for the toadfish gill.

Transient apoptosis elicited by insulin in serum-starved glioma cells involves Fas/Fas-L and Bcl-2

The expression of fas gene in glioma cells varies with growth stage. When insulin-elicited transient apoptosis of glioma cells was in progress, the expression of fas gene increased at both transcriptional and translational levels. In contrast, the expression of fas-L gene in glioma cells remained constant. Apoptosis occurred in the cells having high level of surface Fas protein. When the expression of Fas-L in U-373MG cells was suppressed by ribozyme, the insulin-elicited transient apoptosis vanished. Overexpression of Bcl-2 in U-373MG cells did not alter significantly the cell cycle progression and the expression of fas gene. However, these cells were resistant to insulin-trigged death. Therefore, insulin-elicited apoptosis involved Fas-related death signal, and which could be prevented by the protective effect of Bcl-2.

Ras signaling is involved in the expression of Fas-L in glioma

Fas-L expresses on a variety of tumors and is suspected to modify the dialog between tumor and the immune system. However, the cellular abnormality in tumor cells leading to an aberrant expression of Fas-L is unclear. In this study, we demonstrate the involvement of Ras signaling in the Fas-L expression in several ways. First, the activated Ha-rasval12 gene enhanced the Fas-L expression of primary human glial cells. Second, blocking the Ras signal pathway in glioma cells by lovastatin or the Ha-rasAsn17 dominant-negative mutant gene resulted in reduced Fas-L expression. Transfection of the Ha-rasAsn17 into glioma cells also inhibited the activation of NFKB, which is a downstream component of Ras signaling. Accordingly, the membrane-permeable NFKB competitor suppressed the Fas-L expression. Furthermore, the Fas-L expression coincided with the Ras activity in the murine 212 cells, in which the Ras activity could be induced by isopropyl 3-D-thiogalactoside. In summary, these results suggest that the enhanced Ras signaling with consequential NFKB activation, which is a frequent defect found in tumors, could mediate the Fas-L expression of tumors.

An efficient method for in vitro fertilization in rabbits

This experiment was carried out to study a simple and efficient method for in vitro production of rabbit embryos. Newly ejaculated rabbit spermatozoa were used to fertilize superovulated oocytes after capacitation in vitro with four different media: (A) isotonic defined medium (DM)+heparin, (B) DM only,(C) DM+ high ionic strength defined medium (HIS), and (D) DM supplemented with 10mM NaHCO3 (mDM) +HIS supplemented with 10mM NaHCO3 (mHIS). The presumptive zygotes were cultured in M199 supplemented with 10% FCS, 1.25mM Na Pyruvate and 0.1mM EDTA (mM199). The cleavage rates after 24h of incubation were 29.3%, 32.1%, 64.9%, and 91.6% respectively, and the rates of blastocyst formation after 72h were 0, 27.3%, 58.4% and 85.2%, respectively. The results in the (D) treatment were significantly better than the other three treatments (p<0.01). Developmental potential of in vivo and in vitro derived zygotes was also compared using the mM199. The percentages of blastocyst and hatching blastocyst in the two groups were 92.5% and 87.2% after 84h, and 84.9% and 83.7% after 108h, respectively, and the two groups were not significantly different (p>0.05). The developmental progress of the two groups was nearly synchronous towards the end of culture. When IVF embryos from 2- to 4-cell stage were transferred into recipients, the pregnancy rate did not differ from in vivo fertilization, but the rate of live young from IVF was significantly lower than from in vivo. The results of this experiment showed that ejaculated rabbit sperm could be capacitated efficiently after treatment of mDM and mHIS, and rabbit IVF embryos achieved great development in mM199 in vitro.

Induction of carbamoyl phosphate synthetase III and glutamine synthetase mRNA during confinement stress in gulf toadfish (Opsanus beta)

Gulf toadfish (Opsanus β) rapidly switch to excretion of urea as their main nitrogenous waste product under several laboratory conditions, including confinement to small volumes of water. Prior evidence suggested that the activities of two key enzymes of urea synthesis exhibited potentially different modes of upregulation during this switch, with carbamoyl phosphate synthethase III (CPSase III) activated allosterically by N-acetylglutamate, and glutamine synthetase (GSase) activated by increases in the concentration of protein. The present study was undertaken to examine additional aspects of the regulation of these enzymes. The sequence for O. beta CPSase III cDNA was obtained, and it was found to be similar to that of other piscine CPSases. The sequence also allowed us to develop riboprobes for CPSase III mRNA analysis using ribonuclease protection assays (RPAs). CPSase III mRNA was expressed in liver, muscle, kidney and intestine, in agreement with prior enzymatic measurements. Levels of CPSase III mRNA increased five- to tenfold (relative to beta-actin mRNA) in liver (but not muscle) following 48 h of confinement stress. Measured by western analysis using an antibody to chicken GSase, confined O. beta GSase protein concentrations increased eightfold over control levels, in agreement with prior and present measurements of increases in GSase activity. Furthermore, RPAs of GSase mRNA levels demonstrated an increase of fivefold during confinement.

Potential of the insecticides acephate and methamidophos to contaminate groundwater

The possible contamination of groundwater by the insecticides acephate and methamidophos was assessed using the behavior assessment model (BAM) and the groundwater pollution-potential model (GWP). The dissipation coefficients of the two insecticides in two soils (Annei silt loam and Pingchen silt clay loam) at different moisture contents (50 and 100% field capacity) and soil temperatures (20 and 30 degrees C) were studied by determining the degradation and adsorption of each insecticide in the soil. The movement of acephate and methamidophos was studied by leaching each insecticide in a soil column in the laboratory. The absorption coefficient of methamidophos was much higher than that of acephate in both types of soil. In the leaching test, methamidophos more easily leached out from the Pingchen soil column than from the Annei soil column. Methamidophos was rapidly degraded, with a half-life of 1.11 to 1.61 days in the Annei soil and 7.50 to 13.20 days in the Pingchen soil at different temperatures and soil water contents. Acephate was found to have a longer half-life than methamidophos in soil; however, the mobility of methamidophos in both soils was slower than that of acephate. The mobility of acephate in soil is somewhat faster than that of methamidophos, and thus acephate may lead to the contamination of groundwater much more easily than methamidophos under normal conditions.

Two-photon optical-beam-induced current imaging of indium gallium nitride blue light-emitting diodes

Epilayers of packaged indium gallium nitride light-emitting diodes (LED's) are characterized by optical-beam-induced current (OBIC) and photoluminescence laser-scanning microscopy through two-photon excitation. Light scattering and absorption in the packaging material and the p-doped top layer of the LED's are greatly reduced as a result of employing a longer excitation wavelength, with energy that is less than the bandgap of the top p layer. Compared with single-photon OBIC, two-photon OBIC imaging not only exhibits superior image quality but also reveals more clearly the characteristics of the epilayers that are being focused on.