Molecular structure of a cyclic tetrapeptide disulfide. A novel 310 helical conformation with an S-S bridge

The crystal structure of the cyclic peptide disulfide Boc-Cys-Pro-Aib-Cys-NHMe has been determined by X-ray diffraction. The peptide crystallizes in the space group P212121, with A = 8.646(1), B = 18.462(2), C = 19.678(3)Å and Z = 4. The molecules adopt a highly folded compact conformation, stabilized by two intramolecular 4→ 1 hydrogen bonds between the Cys (1) and Pro (2) CO groups and the Cys (4) and methylamide NH groups, respectively. The backbone conformational angles for the peptide lie very close to those expected for a 310 helix. The S-S bridge adopts a right handed twist with a dihedral angle of 82°. The structure illustrates the role of stereochemically constrained residues, in generating novel peptide conformations. Aib, α-aminoisobutyric acid; Z, benzyloxycarbonyl; Boc, t-butyloxycarbonyl; OMe, methyl ester; OBz, benzyl ester; NHMe, N-methylamide; Tosyl, p-toluenesulfonyl.

On the Importance of Mutual Fund Families in Emerging Markets

This study contributes to the mutual fund literature by looking at performance persistence on a fund family level, allowing for individual equity, bond and balanced funds to be included under single family umbrellas. The study is conducted on the emerging Finnish mutual fund market, an environment in which the importance of superior fund family teams is likely to be accentuated. Using both non–parametric and parametric tests we find robust evidence of performance persistence for the fund families. Persistence is particularly strong in the first half of the investigation period, which highlights the importance of fund families at early stages of market development.

Copper( 11) Complexes of Novel Tripodal Ligands containing Phenolate and Benzimidazole/Pyridine Pendants: Synthesis, Structure, Spectra and Electrochemical Behaviour

Mononuclear copper(II) complexes of tri- and tetra-dentate tripodal ligands containing phenolic hydroxyl and benzimidazole or pyridine groups have been isolated. They are of the type (CuL(X)].nH2O, [CuL(H2O)]X.nH2O or [CuL].nH2O where X = Cl-, ClO4-, N3- or NCS- and n = 0-4. The electronic spectra of all the complexes exhibit a broad absorption band around 14000 cm-1 and the polycrystalline as well as the frozen-solution EPR spectra are axial, indicating square-based geometries. The crystal structure of [CuL(Cl)] [HL = (2-hydroxy-5-nitrobenzyl)bis(2-pyridyl-methyl)amine] revealed a square-pyramidal geometry around Cu(II). The mononuclear complex crystallises in the triclinic space group P1BAR with a = 6.938(1), b = 11.782(6), c = 12.678(3) angstrom and alpha = 114.56(3), beta = 92.70(2), gamma = 95.36(2)-degrees. The co-ordination plane is comprised of one tertiary amine and two pyridine nitrogens and a chloride ion. The phenolate ion unusually occupies the axial site, possibly due to the electron-withdrawing p-nitro group. The enhanced pi delocalisation involving the p-nitrophenolate donor elevates the E1/2 values. The spectral and electrochemical results suggest the order of donor strength as nitrophenolate < pyridine < benzimidazole in the tridentate and nitrophenolate < benzimidazole < pyridine in the tetradentate ligand complexes.

Study of biosorption of rare earth metals (La, Nd, Eu, Gd) by Sargassum sp. biomass in batch systems: Physicochemical evaluation of kinetics and adsorption models

This work evaluated kinetic and adsorption physicochemical models for the biosorption process of lanthanum, neodymium, europium, and gadolinium by Sargassum sp. in batch systems. The results showed: (a) the pseudo-second order kinetic model was the best approximation for the experimental data with the metal adsorption initial velocity parameter in 0.042-0.055 mmol.g -1.min-1 (La < Nd < Gd < Eu); (b) the Langmuir adsorption model presented adequate correlation with maximum metal uptake at 0.60-0.70 mmol g-1 (Eu < La < Gd < Nd) and the metal-biomass affinity parameter showed distinct values (Gd < Nd < Eu < La: 183.1, 192.5, 678.3, and 837.3 L g-1, respectively); and (c) preliminarily, the kinetics and adsorption evaluation did not reveal a well-defined metal selectivity behavior for the RE biosorption in Sargassum sp., but they indicate a possible partition among RE studied. © (2009) Trans Tech Publications.

Leukograms of healthy Holstein calves within the first month of life

To establish reference values and to assess the influence of age on the leukograms of healthy Holstein calves, blood samples were obtained from 300 animals. These samples were distributed equally (n=20) among 15 experimental groups according to age: birth to 8 hours, 9 to 16 hours, 17 to 24 hours, 2 days, 3 days, 4 days, 5 days, 6 to 7 days, 8 to 9 days, 10 to 11 days, 12 to 13 days, 14 to 15 days, 16 to 20 days, 21 to 25 days and 26 to 30 days of age. The maximum numbers of leukocytes (9,305.0/mL), segmented neutrophils (6,551.2/mL) and total neutrophils (6,678.3/mL) were noted within the first 8 hours of life, while band neutrophils peaked in number (133.3/mL) between 9 and 16 hours after birth. Meanwhile, the maximum total lymphocyte (4,992.1/µL) and typical lymphocyte (4,686.1/µL) counts occurred between 21 and 25 days, whereas atypical lymphocytes (388.5/µL) reached their maximum number between 26 and 30 days, demonstrating an inversion of the neutrophil:lymphocyte ratio over time. Thus, the influence of age on the leukocyte count of the evaluated calves was verified. The release of endogenous corticosteroids during labor or at birth may contribute to this variation in leukograms with age.

Normative Influences of "Special and Differential Treatment" on North-South RTAs

Recently, there has been a surge in bilateral and regional trade arrangements between developed and developing countries, which are known as North-South RTAs. Under the current legal system of the WTO, North-South RTAs are governed by Article XXIV of the GATT or Article V of the GATS, which means such RTAs must be reciprocal and must cover substantially all the trade. On the other hand, there is another category of rules on RTAs based on the so-called Enabling Clause, which, in exceptional circumstances, provides special and differential treatment (SDT) for RTAs among developing countries. This paper considers the applicability of the SDT concept to North-South RTAs by examining why rules on RTAs and the concept of SDT were incorporated into the GATT/WTO legal framework so as to permit the derogation of most-favored-nation (MFN) obligations.

Who Uses FTAs?

It is noted that utilization of AFTA is low by international standards. In order to clarify the reasons for such low utilization, this paper investigates what kinds of Japanese affiliates in ASEAN are more likely to use FTAs in their exporting, by employing unique affiliate-level data. Our findings are as follow. First, the larger the affiliate is, or the more diversified its procurements’ origins are, the more likely it is to utilize an FTA scheme in its exporting. Second, affiliates exporting actively to developing countries are more likely to use FTAs than those exporting to developed countries. Third, there are clear differences in FTA utilization depending on affiliates’ locations and sectors. These results afford a clue to the reasons for the low FTA utilization in East Asia.

Measuring fixed costs for firms' use of a free trade agreement : threshold regression approach

In this paper, by employing the threshold regression method, we estimate the average tariff equivalent of fixed costs for the use of a free trade agreement (FTA) among all existing FTAs in the world. It is estimated to be 3.2%. This global estimate serves as a reference rate in the evaluation of each FTA’s fixed costs.

The role of Preferential Trade Agreements (PTAs) in facilitating global production networks

This paper examines the effects of preferential trade agreements (PTAs) in facilitating international trade flows connecting production networks. We consider over 250 PTAs with trade flows distinguished into parts and components and final goods for the period 1979-2008. The gravity equation estimates suggest that the concurrent year effects of PTA formation on trade in parts and components are unseen, whereas PTAs have positive and pervasive effects on both types of trade flows 6 and 9 years after the PTA formation.

Bilateral tariff rates in international trade : finished goods versus intermediate goods

In this paper, we examined back-and-forth international transactions through tariff reduction by estimating modified gravity equations for finished goods and intermediate goods separately. Our main findings are as follows. Exports of finished machinery products are negatively associated with not only the importer's tariff rates on finished machinery products but also the exporter's tariff rates on machinery parts. Similarly, exports of machinery parts are negatively associated with not only the importer's tariff rates on machinery parts but also the exporter's tariff rates on finished machinery products. These results imply that tariff reduction in only one production process in an industry has the potential to drastically change the magnitude of trade in the whole industry.

Non-conventional provisions in regional trade agreements : do they enhance international trade?

The scope of recent regional trade agreements (RTAs) is becoming much wider in terms of including several provisions such as competition policy or intellectual property. This paper empirically examines how far advanced, non-conventional provisions in RTAs increase trade values among RTA member countries, by estimating the gravity equation with more disaggregated indicators for RTAs. As a result, we find that the provision on competition policy has the largest impacts on trade values, following that on government procurement. Our further analysis reveals that the more significant roles of these two provisions can be also observed in the impacts on the intensive and extensive margins.

How serious is the omission of bilateral tariff rates in gravity?

In this paper, using the worldwide dataset of bilateral tariff rates, we explore how serious the omission of bilateral tariff rates in gravity is. Our findings are as follow. Firstly, the omission of bilateral tariff rates seems not to be so serious in terms of omitted-variable biases because the coefficients for the usual gravity variables do not change before or after their inclusion. Secondly, while the widely-used dummy variable of regional trade agreement could not play an alternative role in place of tariff rates, the inclusion of time-invariant pair fixed effects in addition to the time-variant importer fixed effects and exporter fixed effects accounts for the omission of tariff rates. The inclusion of those fixed effects makes the coefficient for bilateral tariff rates insignificant.

How do free trade agreements change import prices? : firm-level evidence from China's imports from ASEAN

The literature has revealed the positive impacts of free trade agreements (FTAs) on export prices by employing product-level trade data. This paper empirically examines the impacts of FTAs on import prices at the firm level. We focus on firm-level imports in China from ASEAN countries by employing China’s firm-product-level trade data. As a result, controlling for firm characteristics and product characteristics, we could not find significantly positive impacts of an FTA’s entry into force on import prices of FTA eligible products. Instead, we found a significant increase in import quantities of FTA eligible products. Thus, at the firm level, the gains from FTAs for exporters may be the increase in export quantities rather than the rise in export prices.