A mixed-unit input-output model for environmental life-cycle assessment and material flow analysis

Materials flow analysis models have traditionally been used to track the production, use, and consumption of materials. Economic input-output modeling has been used for environmental systems analysis, with a primary benefit being the capability to estimate direct and indirect economic and environmental impacts across the entire supply chain of production in an economy. We combine these two types of models to create a mixed-unit input-output model that is able to bettertrack economic transactions and material flows throughout the economy associated with changes in production. A 13 by 13 economic input-output direct requirements matrix developed by the U.S. Bureau of Economic Analysis is augmented with material flow data derived from those published by the U.S. Geological Survey in the formulation of illustrative mixed-unit input-output models for lead and cadmium. The resulting model provides the capabilities of both material flow and input-output models, with detailed material tracking through entire supply chains in response to any monetary or material demand. Examples of these models are provided along with a discussion of uncertainty and extensions to these models.     

Deficiency of co-chaperone immunophilin FKBP52 compromises sperm fertilizing capacity

FKBP52 is a member of the FK506-binding family of immunophilins and serves as a co-chaperone for steroid hormone nuclear receptors to govern appropriate hormone action in target tissues. Male mice missing Fkbp52 are infertile, and this infertility has been ascribed to compromised sensitivity of the anterior prostate, external genitalia, and other accessory sex organs to androgen. Here, we show additional defects contributing to infertility. We found that epididymal Fkbp52(-/-) sperm are sparse often with aberrant morphology, and they have reduced fertilizing capacity. This phenotype, initially observed in null males on a C57BL/6/129 background, is also maintained on a CD1 background. Expression studies show that while FKBP52 and androgen receptor are co-expressed in similar cell types in the epididymis, FKBP52 is also present in epididymal sperm flagella. Collectively, our results suggest that reduced number and abnormal morphology contribute to compromised fertilizing capacity of Fkbp52(-/-) sperm. This study is clinically relevant because unraveling the role of immunophilin signaling in male fertility will help identify new targets for male contraceptives and/or alleviate male infertility.     

Microbial synthesis of magnetite and Mn-substituted magnetite nanoparticles: influence of bacteria and incubation temperature

Microbial synthesis of magnetite and metal (Co, Cr, Ni)-substituted magnetites has only recently been reported. The objective of this study was to examine the influence of Mn ion on the microbial synthesis of magnetite nanoparticles. The reductive biotransformation of an akaganeite (beta-FeOOH) or a Mn-substituted (2-20 mol%) akaganeite (Fe(1-x)Mn(x)OOH) by Shewanella loiha (PV-4, 25 degrees C) and Thermoanaerobacter ethanolicus (TOR-39, 60 degrees C) was investigated under anaerobic conditions at circumneutral pH (pH = 7-8). Both bacteria formed magnetite nanoparticles using akaganeite as a magnetite precursor. By comparison of iron minerals formed by PV-4 and TOR-39 using Mn-mixed akaganeite as the precursor, it was shown that PV-4 formed siderite (FeCO3), green rust [Fe2+Fe3+(OH)16CO3 x 4H2O], and magnetite at 25 degrees C, whereas TOR-39 formed mainly nm-sized magnetite at 60 degrees C. The presence of Mn in the magnetite formed by TOR-39 was revealed by energy dispersive X-ray analysis (EDX) is indicative of Mn substitution into magnetite crystals. EDX analysis of iron minerals formed by PV-4 showed that Mn was preferentially concentrated in the siderite and green rust. These results demonstrate that coprecipitated/sorbed Mn induced microbial formation of siderite and green rust by PV-4 at 25 degrees C, but the synthesis of Mn-substituted magnetite nanoparticles proceeded by TOR-39 at 60 degrees C. These results indicate that the bacteria have the ability to synthesize magnetite and Mn-substituted magnetite nano-crystals. Microbially facilitated synthesis of magnetite and metal-substituted magnetites at near ambient temperatures may expand the possible use of specialized ferromagnetic nano-particles.     

Soft-chemical synthesis and electrochemical characterization of multicomponent Mn(1-x-y)Co(x)Ni(y)O2 nanostructures

Nanostructured Mn(1-x-y)Co(x)Ni(y)O2 metal oxides are synthesized by one-pot hydrothermal reaction at low temperature. From powder X-ray diffraction and field emission-scanning electron microscopic analyses, it is found that the crystal structure and crystal morphology of the present materials are tunable by the control of the composition of precursor. 1D nanowires with alpha-MnO2-type structure are prepared with low substitution rate of Co and Ni, while the increase of substituent contents leads to the formation of delta-MnO2-structured 3D nanospheres consisting of 2D nanoplates. According to X-ray absorption near edge spectroscopy and chemical analyses, mixed valent Co(III)/Co(IV) and divalent Ni(II) ions are stabilized in the octahedral Mn sites of alpha-MnO2- and delta-MnO2-structures. The electrochemical measurements clearly demonstrate that the present nanostructured materials show promising electrode performances for lithium secondary batteries.     

Interaction of murine MHC class I molecules with tapasin and TAP enhances peptide loading and involves the heavy chain alpha3 domain

In human cells the association of MHC class I molecules with TAP is thought to be mediated by a third protein termed tapasin. We now show that tapasin is present in murine TAP-class I complexes as well. Furthermore, we demonstrate that a mutant H-2Dd molecule that does not interact with TAP due to a Glu to Lys mutation at residue 222 of the H chain (Dd(E222K)) also fails to bind to tapasin. This finding supports the view that tapasin bridges the association between class I and TAP and implicates residue 222 as a site of contact with tapasin. The inability of Dd(E222K) to interact with tapasin and TAP results in impaired peptide loading within the endoplasmic reticulum. However, significant acquisition of peptides can still be detected as assessed by the decay kinetics of cell surface Dd(E222K) molecules and by the finding that prolonged viral infection accumulates sufficient target structures to stimulate T cells at 50% the level observed with wild-type Dd. Thus, although interaction with tapasin and TAP enhances peptide loading, it is not essential. Finally, a cohort of Dd(E222K) molecules decays more rapidly on the cell surface compared with wild-type Dd molecules but much more slowly than peptide-deficient molecules. This suggests that some of the peptides obtained in the absence of an interaction with tapasin and TAP are suboptimal, suggesting a peptide-editing function for tapasin/TAP in addition to their role in enhancing peptide loading.     

Usefulness of cholangioscopy in patients with focal stricture of the intrahepatic duct unrelated to intrahepatic stones

BACKGROUND: Intrahepatic duct strictures are usually caused by intrahepatic duct stones and cholangitis. However, focal strictures of the intrahepatic duct unrelated to intrahepatic stones often pose diagnostic problems. This study was undertaken to prospectively evaluate the usefulness of percutaneous transhepatic cholangioscopy in patients with focal intrahepatic duct stricture and no evidence of a stone. METHODS: Seventeen patients with focal strictures of the intrahepatic duct without any evidence of a stone were included. Percutaneous transhepatic cholangioscopic examination including procurement of biopsy specimens was performed after percutaneous transhepatic biliary drainage. RESULTS: A histopathologic diagnosis was obtained in all patients (9 adenocarcinomas, 1 squamous cell carcinoma, 2 hepatocellular carcinomas, 2 adenomas, and 3 benign strictures). Of the 9 patients with bile duct adenocarcinoma, 8 underwent surgery and a curative resection was possible in 7 patients (88%). Five patients (63%) had early-stage bile duct cancer in which cancer invasion was limited to the mucosa or fibromuscular layer and there was no evidence of lymph node metastasis. CONCLUSIONS: Percutaneous transhepatic cholangioscopy in patients with focal stricture of the intrahepatic duct unrelated to choledocholithiasis is useful for diagnosis including the detection of early bile duct cancer.     

Temperature-programmed desorption study of molecular oxygen adsorbed on MFI-type zeolites

The adsorption of molecular oxygen at room temperature on the proton form of MFI zeolites with different Si/Al ratios has been investigated by temperature-programmed desorption (TPD). The internal Si-OH defects (silanol groups) in these zeolites are found to serve as O₂ adsorption sites. The apparent activation energies (17.5–21.8 kcal-mol^-1) of desorption determined from O₂ TPD measurements reveal that the extent of interactions between the Si-OH defects and the adsorbed O₂ molecules becomes weaker with decreasing Al content in the zeolite.     

Effect of MoDDP on the antioxidative properties of ZnDDP in mineral oil

The antioxidative actions of zinc and molybdenum dithiophosphates and their mixtures were evaluated using the RBOT (rotary bomb oxidation test) and the ISOT (Indiana stirring oxidation test). The results showed a synergistic effect on the antioxidative action with certain mixtures of the additives in mineral oil. FTIR spectra indicated the presence of some oxidation products and the degradation of the additives in the additive‐containing oils.