bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the Effects of Environmental Factors on the Response of Wheat to Fertilizer in On-farm Trials in a Mediterranean Type Environment
Authors: Pala M. , Matar A. , Mazid A.
Published: October 2008

A series of researcher-managed wheat fertilizer trials was conducted on representative farmers' fields across northwest Syria between 1986 and 1990. Wheat grain and straw yields were strongly correlated with seasonal (October-May) rainfall, almost irrespective of soil fertility, crop sequence or fertilizer rate, with a highly significant response to nitrogen fertilizer which increased with increasing rainfall and decreasing initial soil mineral-nitrogen values. These results were summarized in regression equations which express yield in terms of fertilizer rates, seasonal rainfall and their interactions. The equations with applied nitrogen and seasonal rainfall were the most appropriate for determining fertilizer needs. Economic analysis indicated that all fertilizer treatment rates were profitable under existing price conditions and that fertilizer use would still be beneficial for a nitrogen price up to three times higher than that of the price of grain (weight for weight) with a seasonal rainfall of 250 mm, and up to six times higher with a seasonal rainfall of 450 mm.
Responses of Young Tea (Camellia Sinensis) Clones to Drought and Temperature. I. Yield and Yield Distribution
Authors: Burgess Paul J. , Carr M. K. V.
Published: October 2008

The yield response to drought and temperature of six contrasting tea clones was studied in a line-source irrigation experiment in Southern Tanzania. The selected clones, all commercially and/or scientifically important in eastern Africa, embrace a range of morphological and physiological types. The bushes were planted in August 1988 and differential drought treatments were imposed for 16 and 13 weeks towards the end of the dry seasons in 1990 and 1991, respectively. The resulting soil water deficits were successfully simulated using a water balance model. Under well-watered conditions Clone S15/10 (from Kenya) gave the highest yield of dry tea, reaching 5600 kg ha−l in the fourth year after planting (1991/92) compared with 3640–4420 kg ha−1 for the other five clones. During the cool season Clone SFS150 (from Malawi) yielded more than Clones 1, 207, 6/8 and K35. Although annual yields decreased curvi-linearly as the maximum soil water deficit increased, single values for the drought sensitivity of each clone could be derived by using stress time as an index of drought. On this basis Clones S15/10 and 207 were identified as being the most sensitive to drought; Clones SFS150 and 1 were drought resistant. The reasons for these differences in yield responses and the importance of determining drought sensitivity over an appropriate time period are discussed.
Improving Crop Production on Salt-affected Soils: by Breeding or Management?
Authors: Richards R. A.
Published: October 2008

The area of salt-affected land is increasing because of irrigation practices and changed land use. Breeding crops that tolerate soil salinity and yield well in salt-affected soils, and employing crop management practices to counter salinity, have been proposed to maintain crop productivity. Here, it is argued that neither breeding nor management will adequately counter the effects of salinity. Although both offer the potential to maintain yields for a brief period, it is inevitable that salinity will continue to increase and crop productivity will decline. Only the establishment of a perennial vegetation that will maintain evapotranspiration at high levels all year round on both salt-affected land and recharge areas will halt the increase in salinization.

Mejorar la producción en los suelos afectados por la sal
Some Design Problems in Crop Experimentation. III. Non-Orthogonality
Authors: Pearce S. C.
Published: October 2008

Ideally each block of an experiment should be made up in the same way with respect to treatments, that is, the design should be ‘orthogonal’. In practice that can be difficult to achieve, especially if the blocks have been chosen to fit the fertility pattern of the field. Sometimes it is impossible, in which case each block will have to contain its own selection of treatments. A number of simple and useful possibilities exist.

Whatever non-orthogonal design is chosen some of the contrasts of interest (perhaps all of them) will be evaluated less efficiently, but that can be compensated by the smaller error mean-square given by a better blocking system. Also, where blocks do differ in their content, comparing their means will provide additional information about treatment effects. Sometimes the information may be worth the trouble of recovery.

Special attention is given in this paper to total balance (including balanced incomplete block designs), supplemented balance, square and rectangular lattices and alpha-designs. The reinforcement of a design is explained and the advantages considered.

Problemas de diseño en la experimentación con cultivos. III
An Analysis of the Effect of Climate and Weather on Coconut (Cocos Nucifera)
Authors: Peiris T. S. G. , Thattil R. O. , Mahindapala R.
Published: October 2008

Studies on the effect of climatic factors such as rainfall, relative humidity, temperature, sunshine hours, pan evaporation, evapotranspiration, solar radiation, vapour pressure and wind velocity on the button shedding, premature nut fall, and final nut yield of coconut, and crop-weather models developed to predict nut yield, are reviewed. The type of data and statistical analyses techniques used and the areas of research poorly addressed under the different topics are highlighted.

Efectos de las condiciones climáticas y el tiempo en el coco
Correction of Systematic Errors in Estimates of Transpiration Obtained Using a Constant Temperature Heat Balance Technique
Authors: Khan Ahmed A. H. , Ong Chin K.
Published: October 2008

Field measurements using 30-month-old grevillea trees indicated that the three main sources of error in sap flow estimation can be overcome by: estimating the temperature bias with the gauge heater switched off or covering the whole trunk with 20 mm thick styrofoam sheet and alumimium foil; or by inserting thermocouples in the stem and accounting for radial and conductive heat losses. These corrections reduce gauge error for tree trunks (50–90 mm diameter) from 10–47% to ±7%. In the absence of a large lysimeter, a comparison of sap flow rates was made by attaching gauges to the trunk and a single terminal branch on the same tree.

Calibrado del flujo de la savia en los árboles del géneroGrevillea
The Role of Rhizobial Biodiversity in Legume Crop Productivity in the West Asian Highlands
Authors: Materon L. A. , Keatinge J. D. H. , Beck D. P. , Yurtsever N. , Karuc K. , Altuntas S.
Published: October 2008

The native rhizobia capable of symbiosis with annually-sown food and forage legume crops in the Turkish highlands were surveyed and estimates made of the numbers and nitrogen fixing efficiency of native Rhizobium leguminosarum with Turkish cultivars of lentil (Lens culinaris Medik.) and vetch (Vicia sativa L.). Native rhizobia were present in medium to high numbers in most samples but the nitrogen fixation efficiency of at least half of the isolates was poor. Vetch was somewhat less specific in its rhizobial compatibility than lentil, suggesting a potential for artificial inoculation to improve the productivity and sustainability of cropping in both species especially in areas of central and eastern Anatolia where legumes are not traditionally grown.

Biodiversidad en el Rhizobium leguminosarum
Sample Surveys of Pests and Diseases of Tea in North-East India
Authors: Sen A. R. , Sarkar A. R. , Chakrabarty R. P.
Published: October 2008

Pests and diseases cause appreciable loss to tea in north-east India, but their incidence and intensity of attack vary widely from district to district, and within districts with variation in climate, elevation and the jat (seed-source) of tea. For example, blister blight is a serious disease in Darjeeling and looper catepillar is mainly localized in certain tea estates of the Assam valley. Thus recommendations regarding pesticides and their application in a particular region must be based on a thorough knowledge of the distribution of the diseases or pests in the region. This can best be obtained through sample surveys, planned in representative estates of the region and carried out with the help of trained investigators. Such surveys will also provide basic data on jat, environment and disease, as a guide to experimentation.
Microbial Rotting of Stored Yams (Dioscorea spp.) in Nigeria
Authors: Okafor N.
Published: October 2008

The incidence of rotting among three varieties of yams (Dioscorea rotunda, D. alata and D. cayenensis), stored in a yam barn at Ibadan for about four months, was between 0·6 and 68·5 per cent. The micro-organisms which caused rotting on experimental re-inoculation into yam tubers were the fungi, Botryodiplodia theobromae, Penicillium sp., Marcophomina phaseoli, Hendersonula toruloidea and a motile gram-negative orange-red pigmented bacterim, probably Serratia sp. This is the first record of the ability of M. phaseoli, and H. toruloidea to cause rotting in yam.
Effects of Soil, Cultivation History and Weather on Responses of Wheat to Fertilizers in Northern Tanzania
Authors: Anderson G. D. , Houston B. G. , Northwood P. J.
Published: October 2008

The nature of the soil, the influence of previous natural grassland, ley, fallow or cultivation, and the weather conditions before and after planting are shown to affect the yield of wheat, and its response to fertilizers, especially nitrogen. Out of seventeen experiments over four seasons, involving nitrogen top-dressings on wheat, thirteen gave economic increases after the application of I cwt per acre of ammonium sulphate nitrate (A.S.N.). Such applications to the first, second or third wheat crops after Rhodes grass (Chloris gayana) ley, or to land continuously cropped for a number of years, nearly always gave an economic increase in grain yield, but on continuously cultivated land, with normal rainfall after planting, an economic return to a second cwt per acre was probable. Following a one-season fallow, economic responses to nitrogen only occurred when the pre-planting period was very wet. Yields of wheat after ley, both with and without applied nitrogen, tended to be superior to those on continuously-cropped land. Responses to phosphorus only occurred in one area, where the importance of applying both N and P, particularly to newly-ploughed grassland, was very evident. Loss of organic matter, and structural deterioration accompanied by lower efficiency in the utilization of water and nitrogen, are probably the main causes of falling yields on soils cultivated for many years. The use of grass/legume leys is suggested as the best means of maintaining these naturally fertile soils in a highly productive state, even though the present returns from the legs themselves may be less profitable than wheat cropping.
Use of Rank Correlation Methods to Determine Food Preferences
Authors: Jowett D.
Published: October 2008

Certain statistical techniques, useful in collecting and interpreting ordinal data, are described and their applicability in plant breeding explained. It is suggested that these statistical techniques may be particularly valuable to plant breeders in determining taste Preferences. A series of experiments are described, investigating the taste Preferences of the Itero of Uganda, who show a strong preference for a mixture of cassava, sorghum and Eleusine millet for food. They do not apparently prefer white sorghum grains for food, nor coloured grains for beer, although such Preferences have been recorded elsewhere. They dislike maize and Pennisetum millet. It is suggested that an experimental approach to quality in the breeding of tropical food crops is both desirable and possible, using rank correlation techniques.
Responses to Grazing Intensity on the Transvaal Highveld
Authors: Gillard P.
Published: October 2008

The productivity of climax and serai grassland in South Africa was compared at three stocking rates with steers. On climax grassland, over nine years, gains per head at one steer per morgen (= 2·12 acres = 0·86 hectare) were not significantly greater than at two steers per morgen. Liveweight gains per morgen were 70 per cent higher at the heavier stocking rate and were 162 lb and 273 lb at one and two steers respectively. On serai grassland, over three seasons stocked at two steers and three steers per morgen, the liveweight gains per steer were significantly less at the higher stocking rate but there was no significant difference in the gains per morgen, which were 366 lb and 318 lb at two and three steers respectively. The liveweight gains on the seral grassland were significantly higher than on the climax grassland at the same stocking rate Calculation of the total digestible nutrients (T.D.N.) has shown that with heavier stocking more T.D.N. per morgen may be harvested on both grassland types. However, with heavy grazing the efficiency of conversion of T.D.N. into liveweight was less. The quality of the sward, measured in per cent crude protein, P2O5 and crude fibre was better at the heavier stocking owing to delayed maturity of the grass when it is continually grazed short.
Factors Influencing the Survival of Propagules of Tall Fescue (Festuca arundinacea Schreb.)
Authors: Miltimore J. E.
Published: October 2008

Propagules of five tall fescue genotypes, planted monthly, from April to December, made the greatest growth in April and September and the least in December. Despite the diverse geographic origin of the genotypes, there was no indication of interaction between genotypes and daylength. Propagules grew more vigorously when cut just above the basal leaf sheath then when cut to two or three inches in length. The complete removal of roots, which would facilitate planting, did not reduce growth and appeared to enhance the development of new roots. Propagules consisting of two or three culms grew more vigorously than those consisting of a single culm. Accordingly, if propagules were fragile or if survival was poor, two-culm propagules would become established more readily. Genotypes differed in growth rate even when planting weights were kept uniform. Results of this study could be used to reduce the time and cost of vegetative propagation of tall fescue.
Factors Influencing the Survival of Propagules of Tall Fescue (Festuca arundinacea Schreb.)
Authors: Miltimore J. E.
Published: October 2008

Propagules of 74 genotypes of tall fescue, consisting of parent and progeny groups, were grown in a glasshouse. The number of surviving propagules were determined after one month and at that time, increment weight (growth) and leaf and root weights were determined. Broad-sense heritability estimates were calculated on the whole population and on two individual parent and progeny groups. The criteria measured varied in heritability between groups, but for the 74 genotypes the values had a more limited range from 57 per cent for root weight to 70 per cent for increment weight. Capacity to survive vegetative propagation was dependent on leaf growth and not on root growth or size of propagule. Because of the variation in survival, this characteristic warrants consideration in a selection program where propagation will be utilized for commercial purposes.
ACCOUNTING FOR SPATIAL VARIABILITY IN FIELD EXPERIMENTS ON TEA
Authors: PEIRIS T. U. S. , SAMITA S. , VERONICA W. H. D.
Published: October 2008

Spatial variability among experimental units is a common problem in field experiments on tree crops such as tea (Camellia sinensis). Spatial variability is partly accounted for by blocks, but a substantial amount remains unaccounted for and this may lead to erroneous conclusions. In order to capture spatial variability in field experiments on tea, six commonly used spatial analysis techniques were investigated: Covariate method with pre-treatment yield as the covariate, Papadakis and the Modified Papadakis nearest neighbour adjustments, Moving means and Modified moving means methods, and Autoregressive method. The data from long-term fertilizer experiments and cultivar evaluation trials, conducted at different locations by the Tea Research Institute of Sri Lanka, were used in the study. Spatial techniques were evaluated by means of their relative efficiency at each location and year. Evaluation of the four neighbour methods analysed in conjunction with the pre-treatment yield, revealed that spatial variability due to both past and current conditions are operative, especially in experiments with large blocks, and could be captured simultaneously. Relative efficiencies averaging 141% clearly indicated that the neighbour techniques in combination with pre-treatment yield would be effective in controlling the experimental error in tea experiments with large blocks (nine plots per block or more). Experiments with small blocks were not affected by spatial variability due to past conditions and only that due to current conditions need to be addressed. Neighbour techniques, on their own, were found to be adequate to capture spatial variability due to current conditions. The modified Papadakis technique was found to be the best with an average relative efficiency of 145%. The techniques investigated in the study can easily be implemented using standard statistical software. The precision of tea experiments could be increased by using covariate analysis with pre-treatment yield and any one of the four nearest neighbour adjustments tested, when the block size is large; and modified Papadakis technique, on its own, when the block size is small.
BIOMASS AND CAFFEOYL PHENOLS PRODUCTION OFECHINACEA PURPUREAGROWN IN TAIWAN
Authors: CHEN C. L. , ZHANG S. C. , SUNG J. M.
Published: October 2008

Echinacea purpureahas been introduced in to Taiwan and grown successfully. However, information regarding the effects of the growing climate on its active constituents (e.g. caffeoyl derivatives) and biomass production is very limited. In this study the biomass of field-grownE. purpureaplants harvested during three different crop seasons was compared. The content of caffeoyl phenols and the production of aerial plant parts were also assayed. The results indicated that both morphological and agronomic traits were affected by crop season, with spring-grown plants producing more stems and flowers but fewer leaves than autumn-grown plants. Autumn-grown plants produced more caffeoyl phenols, particularly cichoric acid and caftaric acid, in leaf and flower tissues than spring grown plants. Thus, transplantingE. purpureaseedlings in the autumn and harvesting the aerial parts at the beginning of winter first, and then harvesting the rhizome-regenerated plants again in the following summer are technically feasible. This farming system would give commercial cultivation ofE. purpureain Taiwan a great competitive advantage over other growing regions, provided that an environmentally suitable population is selected and established in Taiwan.
EFFECTS OF GRAFTING ON TEA 1. GROWTH, YIELD AND QUALITY
Authors: TUWEI G. , KAPTICH F. K. K. , LANGAT M. C. , CHOMBOI K. C. , CORLEY R. H. V.
Published: October 2008

Trials in Kenya have shown that yields of tea clones can be increased significantly by grafting onto suitable rootstocks, with the best combinations giving profitable yield increases compared to straight cuttings. However, stock × scion interactions were significant, and not all clones gave useful responses to grafting even onto the best rootstocks, so combinations must be tested individually before commercial planting is considered. The effect of grafting was to increase the number of shoots harvested, with little change in mean shoot weight. Grafting had little or no effect on quality of the tea produced. Attempts to find a method of identifying good rootstocks without testing them in grafting trials were inconclusive.
BARLEY AND VETCH YIELDS FROM DRYLAND ROTATIONS WITH VARYING TILLAGE AND RESIDUE MANAGEMENT UNDER MEDITERRANEAN CONDITIONS
Authors: PALA M. , RYAN J. , DIEKMANN J. , SINGH M.
Published: October 2008

With increasing land-use pressure in semi-arid, dryland Middle Eastern agriculture, fallow-based cereal production has given way to cropping intensification, including legume-based rotations along with conservation tillage and on-farm straw disposal. Such agronomic developments can only be biologically and economically assessed in multi-year trials. Thus, this 10-year study examined the influence of tillage systems (conventional and shallow or conservation) and variable stubble management, including compost application, on yields of barley and vetch grown in rotation. Barley yielded higher with compost applied every two or four years than with burning or soil-incorporating the straw and stubble. Barley straw and grain yields were generally higher with the mouldboard plough. Similarly with vetch, treatments involving compost application yielded significantly higher than burning or incorporating the straw and stubble. Despite yearly differences between crop yields, the pattern of treatment differences was consistent. Thus, the cereal–vetch rotation system is sustainable, while excess straw could be used as compost with benefit to the crop. Though there was no clear advantage of the shallow conservation-type tillage, the energy costs are less, thus indicating its possible advantage over conventional deep tillage in such rotational cropping systems
TEM investigation of MoSeC films
Authors: Sandu C. Silviu , Polcar Tomas , Cavaleiro Albano
Published: October 2008

Transition metal dichalcogenides (TMD) are widely used as self-lubricating material either as oil additive or directly as thin films. Magnetron sputtering is a deposition method allowing depositing such films with high density and adhesion. However, their spread use in practical applications is still hindered since their excellent sliding properties are deteriorated in the presence of humidity and under high contact pressures. MoSe2, one of the members of TMD family recently studied, has been co-sputtered with carbon in order to improve the mechanical and tribological properties when compared to pure MoSe2 films.
Ni4Ti3 Precipitation during Ageing of MARES NiTi Shape Memory Alloys Studied by FEG-SEM
Authors: Neves F. , Cunha A. , Martins I. , Correia J.B. , Oliveira M. , Gaffet E.
Published: October 2008

The use of a high-brightness field-emission gun (FEG) in scanning electron microscopy (SEM) is a powerful technique to examine microstructures at very high spatial resolution down to nanometer level and has significantly enhanced our ability to solve challenging materials problems, allowing studies of nanoprecipitates.
Characterizing the intermetallic formed during ball attach process
Authors: Pereira Paulo , Santos Rúben , Barbosa Maria M. , Almeida Cátia
Published: October 2008

Continuously miniaturization of electronic components using PCB's technology for the manufacturing of SDRAM's uses a solder ball attach process, producing a joint which robustness and electrical response are crucial factors to success. At present, near-eutectic Sn-Ag-Cu alloys are the leading candidates for Pb-free solders. According to Chun et al., the rapid formation of Cu-Sn intermetallic compounds at the interface affects the reliability of this solder joint and represents a major concern. In this study we characterize the interface of an attachment between the copper layer conductors of a memory and a solder ball which allows further bonding to printed circuit modules, see figure 1.a.
Microstructural Characterization of Thick PZT films on Cu Foils Deposited by Electrophoresis
Authors: Wu Aiying , Vilarinho P.M. , Kingon A.I. , Reaney I.
Published: October 2008

Piezoelectric and electrostrictive responses in poled and unpoled ferroelectric and relaxor ferroelectric compositions are of importance in transducers for converting electrical to mechanical impulses and vice-versa. Sensor applications make use of the very high piezoelectric constant dijk of the converse effect, which also permit efficient conversion of electrical to mechanical response. One of the most important families of materials for piezoelectric applications is Pb(Zr,Ti)O3(PZT). The most widely studied composition of PZT lies at the boundary between the tetragonal and rhombohedral phases, known as the morphotropic phase boundary (MPB) and exhibits greatly enhanced dielectric and piezoelectric properties in bulk and thin film. In modern electronic applications, pyroelectric detectors, piezoelectric microsensors, and micromechanical pumps require the integration of PZT films into a variety of device structures. To get sufficiently large piezoelectric strains for optimization of the performance and reliability of the device, thick films in the thickness range of 5–50 μm are desired. On the other hand burying the device components within the substrate is of utmost importance for miniaturization. In comparison to traditional surface mounted components embedded ones will free surface space for a higher functionality of the device, reduce solder points and increase device reliability. Additionally, to reduce the device costs the use of flexible copper foil as substrates is of particular interest. Its high conductivity and compatibility with printed circuit boards makes copper an attractive candidate substrate for embedded application. However, depositing PZT thick films on copper is not trivial, due to the conflict between the high temperature required to sinter PZT (∼1150°C) and low melting temperature of Cu (∼1050°C), in addition to the easy oxidation of Cu. As a consequence the preparation of PZT thick films on Cu involves a complex route to decrease the ceramic sintering temperature and to control the oxygen partial pressure. So far, no successful deposition of PZT thick films on copper foils was reported.
TEM Characterization of W-O-N Coatings
Authors: Parreira N.M.G. , Pei Y.T. , Galvan D. , Polcar T. , De Hosson J.Th.M. , Cavaleiro A.
Published: October 2008

Recently, a new class of coatings based on oxynitrides has drawn much attention in the research field as well as in industrial applications, as shown by either the large numbers of recent publications on TM O N systems (TM—transition metal) such as Ti-O-N, Zr-O-N and Ta-O-N, or the development of Si O-N for opto-electronic devices. The properties of these coatings are related to the chemical composition and the structural arrangement. However, the knowledge about the structure of TM-O-N systems is very limited, especially how the structural arrangement of the non-metallic elements is in the lattices. To the best of our knowledge, only a few studies exist on the development of structural models for oxynitrides, based on XRD and/or XPS analysis, as e.g. Si-O-N and Ti-O-N, or on Mössbauer spectrometry for Fe-O-N. TEM was used scarcely for the characterization of TM-O-N coatings possibly due to the damage of the structure by the electron-irradiation as it is reported for Cr-O-N. This work is aimed at the crystallographic understanding of W-O-N sputtered films by using TEM and HR TEM techniques for complementing the information provided by XRD characterization.
Morphology and Structure of Compacted Coated Powders Studied by SEM and TEM
Authors: Simões F. , Trindade B.
Published: October 2008

The interest in titanium based intermetallics, such as Ti-Al alloys, for high temperatures applications has been increased in recent years mainly due to their high plastic deformation resistance, chemistry stability (oxidation and corrosion resistance) and creep and fatigue resistance at high temperatures. However, the industrial application of Ti-Al intermetallics is very limited so far, due to the lack of ductility and fracture toughness at room temperature with associated processing difficulties. To overcome this problem and to improve mechanical properties of Ti-Al intermetallics, a powder mixture with atomic composition of Ti52Al48 was synthesized by mechanical alloying (MA) and subsequently coated with a ductile element (aluminium), by d.c. magnetron sputtering. Later, in order to obtain a compacted material, as final step, the coated MA'ed powders were submitted to hot isostatic pressing (HIP), giving rise to a bulk material. The aim of the current work is to understand the influence of coating layer in mechanical alloyed (MA'ed) powders and the influence in bulk material properties.
In Vitro Behavior and Surface Morphology of Modified 316L Stainless Steel Stents
Authors: Nunes J. , Piedade A.P. , Duarte C.B. , Vieira M.T.
Published: October 2008

When compared with conventional bare metal stents, such as 316L stainless steel, the introduction of drug-eluting stents can promote reduction in the incidence of in-stent restenosis. However, the chemical discrepancy between the metallic stent and the polymeric material that acts as the reservoir for the drug is responsible for some problems during the cardiovascular surgery. Besides the research work aiming at the development of new bulk alloys for stent production, focus as been also directed to the surface modification of these devices. However, the use of functional graded coatings (FGC), i.e., coatings with a gradient of chemical composition between the substrate and the outmost layer, has never been reported in devices for cardiovascular surgery.
Microstructure of Compositionally Graded PZT films Grown by Pulsed Laser Deposition
Authors: Rodrigues S.A.S. , Khodorov A. , Pereira M. , Gomes M.J.M.
Published: October 2008

Ferroelectric films with a composition gradient have attracted much attention because of their large polarization offset present in the hysteresis loops. Lead Zirconate Titanate (PZT) films were deposited on Pt/TiO2/SiO2/Si substrates by Pulsed Laser Deposition (PLD) technique, using a Nd:YAG laser (Surelite) with a source pulse wavelength of 1064 nm and duration of 5-7 ns delivering an energy of 320 mJ per pulse and a laser fluence energy about 20 J/cm2. The film growth is performed in O2 atmosphere (0,40 mbar) while the substrate is heated at 600°C by a quartz lamp. Starting from ceramic targets based on PZT compositions and containing 5% mol. of excess of PbO to compensate the lead evaporation during heat treatment, three films with different compositions Zr/Ti 55/45, 65/35 and 92/8, and two types of complex structures were produced. These complex structures are in the case of the up-graded structure (UpG), with PZT (92/8) at the bottom, PZT (65/35) on middle and PZT (55/45) on the top, and for down-graded (DoG) one, that order is reversed.
Estimation of Ge nanocrystals size by Raman, X-rays, and HRTEM techniques
Authors: Pinto S.R.C. , Caldelas P. , Rolo A.G. , Chahboun A. , Gomes M.J.M.
Published: October 2008

Ge NCs have attracted considerable attention because of their potential applications in nonvolatile memory and integrated optoelectronics. A number of groups have already proposed integrate flash memories based on Ge NCs embedded SiO2 matrix. Since Al2O3 presents a high dielectric constant comparatively to SiO2, it is a good candidate to replace silica in flash memory systems, and therefore improve their performances. Moreover, Al2O3 presents good mechanical properties, and supports high temperature, which leads it to be an ideal material for Si processing conditions. However, a few studies have been reported on Ge NCs embedded in Al2O3 matrix.
Nanoscale Characterization of Hydroxyapatite Particles by Electron Microscopy
Authors: Santos C. , Franke R.-P. , Almeida M.M. , Costa M.E.V.
Published: October 2008

Owing to its chemical similarity to the mineral phase of human bone and to its biological performance, synthetic hydroxyapatite (HA, Ca10(PO4)6(OH)2) has long been recognized as an important bone substitute material in orthopaedics, dentistry and artificial implants. HA ceramics have also been studied as drug delivery systems components where an appropriate porosity for ensuring a high ability forcarryingand delivering drugs in a controlled manner is required. For some emerging applications demanding nanoscale structured systems endowed with novel potentialities HA nanoparticles may be addressed as alternative components ensuring a large surface area for adsorbing the pharmacological substance of interest. Moreover particle porosity may offer new possibilities for drug or nutrient delivery, or for biocompatible and bioresobable structural reinforcements in osteologic implants, coatings and adhesives. Mesostructured porous calcium phosphate based systems have been synthesized at macro- and micro-scale, but well established methods for the specific synthesis of porous HA nanoparticles have not been reported so far. Yao et al. reported a successful synthesis of HA mesoporous micron-sized rods 0.5-1 μm in length and 50-100 nm in thickness but having low porosity. A new synthesis challenge for producing nano-sized particles of high surface area and having ordered mesopores is thus addressed.
Applications of Nuclear Techniques and Microscopy to Surface Analysis of Materials
Authors: Pacheco de Carvalho José A.R. , Reis António D.
Published: October 2008

The importance of surface analysis of materials has been increasing. The available techniques are complementary. Nuclear techniques, which are non-destructive, provide analysis for a few microns near the surface. Using low energy ion beams of a few MeV, applications have been made to several areas. Nuclear reactions and elastic scattering are the more precise nuclear techniques for obtaining absolute values of concentrations in surface analysis. Nuclear reactions provide, not only high sensitivities for detection of light elements in heavy substrates, but also discrimination of isotopes. We consider the “energy analysis method”, where a spectrum is acquired of ions from the target for a single energy of an incident ion beam. The spectrum inherently contains target composition and concentration profile information. A computational procedure has been developed for predicting such energy spectra, where elastic scattering is a particular and important case. The model mainly accounts for: target parameters, such as composition and concentration profiles; energy spread of the incident ion beam; geometric factors and target rotation; stopping power; differential cross section; energy straggling; detector resolution. An option permits inclusion of effects such as: multiple scattering; incident beam size and angular divergence; detector angular aperture. Computer simulated spectra are compared to experimental data. The chi-square is calculated, to evaluate the goodness of fit. Through variation of target parameters, so as to fit experimental data, target composition and concentration profiles are obtained.
Optical microscopy analysis of mortars from Tagus River 16th and 17th century fortifications
Authors: Guerreiro Teresa , Silva Antonio Santos , Adriano Patricia , Candeias Antonio , Mirao Jose
Published: October 2008

Mortars are common and essential elements of masonry historical buildings and are composed by a binder, aggregates and eventually, some additives. The binder provides consistency to this composite material, and until the emergence of Portland cement in the 19th century, lime was the main binder used. The aggregates are normally sand or rock fragments with variable sizes. The whole set is morphologically very similar to a sedimentary clastic rock with carbonate cementing. Following an old tradition of microscope use in this kind of rocks, it is not surprising the application of optical microscopy to mortars as also happened with concrete.
Material flow in Friction Stir Welding
Authors: Leitão C. , Leal R.M. , Rodrigues D.M. , Vilaça P. , Loureiro A.
Published: October 2008

Friction stir welding (FSW) is a solid-state joining technique initially developed for aluminium alloys. The heat generated by a rotating tool softens the material in the vicinity of the tool. The material undergoes intense plastic deformation following quite complex paths around the tool, depending on the tool geometry, process parameters and material to be welded. The comprehension of the material flow is essential to prevent voids and other internal defects which may form during welding. Several techniques have been used for tracking material flow during FSW such as metallography, the use of a marker material as a tracer or the flow visualization by FSW of dissimilar materials or even the X-ray and computer tomography. Some of these techniques are useless in the analysis of welds in homogenous materials or welds between materials of the same group. The aim of this investigation is tracking the material flow in FSW between 1mm thick sheets in aluminium alloys AA 5182-H111 and AA 6016-T4, currently used in automotive industry.
Rediscovering the materials of Arraiolos tapestries: fibre and mordant analysis by SEM-EDS and μ-PIXE
Authors: Manhita Ana , Costa Cristina , Ferreira Teresa , Mirão José , Vargas Helena , Ribeiro Isabel , Seruya Isabel , Pacheco Teresa , Alves Luís , Candeias António
Published: October 2008

Arraiolos tapestries are probably one of the richest artistic Portuguese expressions in terms of textile heritage. It is difficult to date the beginning of the production of rugs in Arraiolos (Southern Portugal), but they were already produced in the late 1600's as they are listed in the inventories of Portuguese aristocratic households in the beginning of the 18th century. Sensitive detection techniques play an increasing role in the chemical investigation of historical objects since the knowledge derived from the chemical composition of materials is of upmost importance for textile conservation and restoration purposes. Textiles deteriorate due to natural causes like heat, radiation, mechanical stress, moisture, microbiological and enzymatic attack. Deterioration of materials causes breakdown of the molecular structure and results in a loss of strength, extensibility and durability, discoloration and fading which affects the appearance of the textiles.
The role of SEM in the diagnosis of expansive chemical reactions in cement-based building materials
Authors: Silva A. Santos , Salta M. Manuela , Menezes P. , Couto S. , Adriano P.
Published: October 2008

The alkali-silica reaction (ASR) and internal sulfatic reaction (ISR), normally both referred as internal expansive reactions, are among the most common causes of concrete structures deterioration worldwide. These reactions, which could be present simultaneously, origin products those are responsible for expansive stresses in the cement-based building materials, leading to severe cracking and loss of strength. The reaction products are also often amorphous or badly crystallized, or even present in very low content that they are very difficult to identify by current analytical physico-chemical techniques. The main macroscopic evidence of these degradation phenomena in concrete structures are the superficial occurrence of map-cracking, pop-outs and exudates (figure 1). Nevertheless, these symptoms are not exclusive and enough to establish a correct diagnosis.
Superoxide Dismutase Detection in Human Cumulus Oophorus Cells
Authors: Matos L. , Stevenson D. , Gomes F. , Silva-Carvalho J.L. , Almeida H.
Published: October 2008

A key factor limiting the success of Assisted Reproduction Techniques (ART) is oocyte and embryo quality, usually assessed by their morphologic appearance. Due to the subjectivity and inaccuracy of such criteria, other predictors of oocyte and embryo quality would be welcome. Cumulus oophorus (c.o.) cells are eligible as oocyte quality predictors, due to their direct contact with it. In addition, ART success was also related to oxidative stress, whose effects in the porcine and bovine oocytes may be prevented by the presence of c.o. cells. Yet, it is unknown if a similar effect exists in humans due to the scarcity of studies employing human c.o. cells.
The Use of SEM and Light Microscopy for the Characterization of Hypericum foliosum Aerial Part as a Medicinal Plant
Authors: Serrano R. , Ferreira P. , Gomes E.T. , Silva O.
Published: October 2008

The first step in quality control of herbal drugs is ensuring the correct identification of the plant intended for use. The required analytical procedures (macroscopic characterization of the entire or fragmentized material, microscopic characterization after pulverization of the plant material and chemical characterization), are usually described on quality monographs reported in authoritarian texts such as the European 6th Pharmacopoeia. Further information related to the name of the each herbal drug, the herbal drug definition, purity tests and assay are also provided.
Keratinophilic Fungi: a microscopic approach by in vitro hair perforation analysis
Authors: Sabino R. , Verissímo C. , Brandão J. , Alves C. , Alves P. , Parada H. , Rosado L.
Published: October 2008

Nowadays, environmental moulds are often being referred as also being the cause of superficial mycosis. Keratinophilic activity is one of the characteristics involved in the infectious process of some fungal species. With these findings some problems appear: 1) Do these species really act on keratinized tissues?; 2) How do these fungi perform their keratinophilic activity?; 3) Should we validate the results as positives in the case of isolating from the lesions only species considered as environmental? To answer to these questions, the in vitro hair perforation test was performed in 60 different species, including dermatophytes and environmental isolates. In vitro perforation capability, believed to be one of the characteristics involved in some fungal infectious processes, was assessed with aid of optic-, fluorescence-, electron scanning- and transmission-microscopy, followed by calculation of keratinophilic activity. According to Ali-Shtayeh et al., each hair degradation factor has a specific weight in a keratinolytic activity intensity index called “IKA”, which ranges between 0 and 100%. Changes in the hair structure may occur in the two following different ways: (a) Superficial Erosion, where there is an even hair degradation from the outside to the inside (b) Radial Penetration where there is a localized degradation of hair surface, often in a pocket-like structure. Different types of hyphæ are observed: of narrow diameter called boring hyphæ, of larger diameter called wider boring hyphæ) and swollen boring hyphæ (with dilated tips). Hyphæ may also produce highly specialized perforation organs.
Refractory Anaemia with Ringed Sideroblasts associated with Marked Thrombocytosis – A Study of Four Cases
Authors: Barreira R. , Ferreira R. , Cortez J. , Gameiro P. , Salazar I. , Silveira M.
Published: October 2008

Some hematological neoplasms share features of myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD), the World Health Organization (WHO) classification of hematopoietic neoplasms introduced a new separate category: myelodysplastic/myeloproliferative diseases (MDS/MPD). Some patients may present diagnostic features of refractory anaemia with ringed sideroblasts (RARS) together with a markedly elevated platelet count (>600x109/L). Provided that these patients do not have del(5q) nor abnormalities of chromosome 3 (3q21q26) and because features of both myelodysplastic and myeloproliferative processes are present, the WHO classification considers this a provisional entity belonging to the MDS/MPD, unclassifiable category. The so-called provisional entity acquired sideroblastic anaemia associated with thrombocytosis/refractory anaemia with ringed sideroblasts (figure 1) associated with marked thrombocytosis (RARS-T) represents a heterogeneous disease, not only in terms of clinical and morphologic features, but also in terms of cytogenetic and molecular findings.
Hepatocyte Growth Factor (HGF) Expression in High-Fat Diet Fed Rat Corpus Cavernosum. Preliminary results
Authors: Tomada I. , Tomada N. , Marques F. , Vendeira P. , Neves D.
Published: October 2008

The main cause of erectile dysfunction (ED) is organic in nature, with vasculogenic etiology being predominant. Several epidemiological studies report the relationship between ED and several well-recognized cardiovascular risk factors, including atherosclerosis, diabetes, dyslipidemia, hypertension, as well as lifestyle factors, such as obesity and sedentarism. Recent findings also indicate that high-fat (HF) regular intake induces endothelial dysfunction and increases ED prevalence. Due to their interconnection, ED is considered equivalent to endothelial dysfunction, and it is nowadays seen as a predictive factor of atherosclerosis and cardiovascular disease (CVD). It is well established that the expression of some vascular growth factors is frequently diminished in corpus cavernosum (CC) of ED patients, and that its levels are particularly modified in metabolic syndrome (MetS). This syndrome combines more than three of the illnesses that prompt to vasculogenic ED: elevated blood pressure, high triglycerides, low high-density lipoprotein (HDL) cholesterol, elevated waist circumference, and insulin resistance. Hepatocyte Growth Factor (HGF) is a pleiotropic factor with potent mitogenic and angiogenic properties, previously employed in the treatment of ischaemic members. Interestingly, it was demonstrated that its serum levels were particularly increased in obesity and in MetS. HGF is expressed by several organs, but as far as we know, it has never been detected in CC. In this way, we present an immunohistochemical (IH) characterization of HGF expression in HF-diet fed rat CC.
Immunolocalization of Histone Modifications as a Tool to Visualize Chromatin Dynamics in Plants
Authors: Geraldo Nuno , Abranches Rita
Published: October 2008

The nuclear DNA of eukaryotic organisms is associated with several proteins. These proteins together with the DNA form chromatin. In all eukaryotes, DNA is folded around a core of histones to form nucleosomes. Chromatin was previously believed to serve mainly to organize and compact the genetic material. However, in recent years, chromatin has been regarded has a highly dynamic structure responsible for controlling gene expression. Therefore, chromatin is highly flexible, to make genetic information accessible when needed, and the degree of compaction has to be tightly regulated. DNA staining, using 4',6-diamidino-2-phenylindole (DAPI), provided the basis for a cytological distinction between weakly stained euchromatin, now known to be gene rich, and brightly stained heterochromatin, which usually contains various repetitive sequences. In many organisms, heterochromatic DNA is hypermethylated and this is used as an additional mechanism to regulate transcription. Histones can be modified by acetylation, phosphorylation, methylation or ubiquitination. These mechanisms provide signals to which other factors can bind and additionally alter the biochemical properties of chromatin (i.e., “histone code”). In general, acetylation of histones is correlated with active genes, whereas methylation of histones at different positions results in changes in gene expression. The methylation of lysine 9 in histone 3 (H3K9) is associated with heterochromatin formation while methylation of lysine 4 of histone 3 (H3K4) methylation is related to gene activation and positioned in euchromatin. DNA and histone modifications recruit various non-histone proteins to specific chromosomal regions and eventually create a defined nuclear structure that is able to affect gene expression.
Ultrastructure of the Effects of Pyrrolidine-fused Chlorins on the Replication of HSV-1
Authors: Matos António P.A. , Santos Ana R.N. , Caeiro Maria F. , Faustino Maria A.F. , Neves M.G.P.M.S. , Tomé A.C. , Cavaleiro José A.S.
Published: October 2008

Currently, only few antiviral drugs of proven effectiveness exist against virus of the Herpesviridae family and viral resistance to these drugs, especially in the immunocompromised hosts, has encouraged research for new drugs. Some porphyrin derivatives revealed a significant antiviral activity against HSV-1 virus. However the cellular target of the porphyrin derivatives in the virus-cell complex remains unknown.