To summarize and critically review the existing literature on the prevalence of posttraumatic stress disorder (PTSD) following organ transplantation, risk factors for posttransplantation PTSD and the relationship of posttransplant PTSD to other clinical outcomes including health-related quality of life (HRQOL) and mortality.We conducted a systematic literature review using PubMed, CINAHL Plus, the Cochrane Library and PsycInfo and a search of the online contents of 18 journals.Twenty-three studies were included. Posttransplant, the point prevalence of clinician-ascertained PTSD ranged from 1% to 16% (n= 738), the point prevalence of questionnaire-assessed substantial PTSD symptoms ranged from 0% to 46% (n= 1024) and the cumulative incidence of clinician-ascertained transplant-specific PTSD ranged from 10% to 17% (n= 482). Consistent predictors of posttransplant PTSD included history of psychiatric illness prior to transplantation and poor social support posttransplantation. Posttransplant PTSD was consistently associated with worse mental HRQOL and potentially associated with worse physical HRQOL.PTSD may impact a substantial proportion of organ transplant recipients. Future studies should focus on transplant-specific PTSD and clarify potential risk factors for, and adverse outcomes related to, posttransplant PTSD.

In rainfed lowland rice fields, developing hardpan soil layers must be important to pool rainfall, but during drought that also restricts water movement from below it. We investigated whether the hardpan can maintain a contrast of deuterium/hydrogen isotopic composition (δD) in soil water under field condition. The experimental site was at Rajshahi in north-west Bangladesh. The hardpan soil layers had developed around 0.2m soil-depth in the field. Soil water from either above or below the hardpan was collected non-destructively with porous cups installed into the field. Using an isotopic ratio mass spectrometer, δD value of each water sample was determined. During the sampling period, the field surface varied from water-saturated to unsaturated status with rainfall event. While the δD values fluctuated by the influence of rainfall, significant differences in the δD values were always detected between above and below the hardpan, revealing heterogeneity in the δD values persisted with the hardpan. The effect of hardpan on retention of the δD signature was further confirmed in a laboratory experiment using intact soil columns collected from a paddy field at Nagoya University. The natural δD signature in rainfed lowland rice field may be useful to identify certain genotypes that demonstrate in situ capability of water acquisition from below the hardpan through δD analysis of the xylem sap.

Transparent, nanocrystalline glass-ceramics based on the aluminogallate spinel crystals Li(Ga,Al)(5)O-8 and "gamma-(Ga,Al)(2)O-3" can be obtained in the SiO2Ga2O3-Al2O3-K2O-Na2O-Li2O system. The glass-ceramics are self-nucleating via amorphous phase separation. Their microstructures consist of 10-20 run spinel crystals dispersed throughout a stable aluminosilicate glass, with total crystallinity ranging from 5-25%. Because gallium-rich spinel crystals contain large Ga ions in both their octahedral and tetrahedral sites, these sites provide a lower crystal field strength environment than that obtained with conventional aluminate spinels. Thus, when doped with transition metal ions such as Ni2+, CO2+, and Cr3+, gallate spinels can yield fluorescence spectra that are significantly shifted toward the infrared compared with those of conventional spinels. Glass-ceramic fibers based on Ni2+-doped aluminogallate spinel have demonstrated strong and broad fluorescence with peak wavelengths of 1200-1250 nm and emission lifetimes of >300 mus.

Rice roots are commonly shallow in rainfed lowland conditions. Mechanical impedance is one factor that may restrict access of roots to deeper soil layers, thereby reducing the capacity of the root system to extract water from depth during late-season drought. The capacity of rice roots to penetrate hardpans was examined in experiments at Rajshahi, Bangladesh, in the 1994 wet season. Eight lines (CT9993, IR52561, IR58821, IR62266, KDML105, Mahsuri, Namsagui19, and IR20) were grown in three experiments: irrigated early, rainfed early, and rainfed late. As drought intensified from heading to dough stage, soil penetration resistance increased to 3.0 MPa at 15–25 cm depth in both rainfed experiments. A high proportion of the total root length was found in the surface layer, particularly in IR20. CT9993 and IR58821 had thicker roots than other lines. Root length density (RLD) increased in deeper soil layers in rainfed with time, but lines differed in their capacity to penetrate the compacted layer as drought intensified after heading. Only IR58821 and Mahsuri were able to increase RLD below 15 cm depth after heading to values greater than 1.6 cm cm−3, and only in the rainfed early experiment. In rainfed late, soil penetration resistance tended to increase after heading in IR20, IR52561 and IR62266, implying these lines were able to extract water below 15 cm depth, but without the concomitant increase in RLD. The greater penetration ability of Mahsuri and IR58821 was expressed in both rainfed environments at high soil penetration resistance.

Summary from only given. The dramatic improvement in the spectroscopic properties obtained by using a nanocrystalline environment for the active ion is clearly worth the trouble of using a glass-ceramic fiber. This, coupled with the improved formability of a glass-ceramic over a single crystal host, is the driving force behind the work presented here.

We report an efficient glass-ceramic fiber laser and show that its slope efficiency (~30%) is not compromised by the presence of Nd-doped fluoride crystals embedded within the core of the single-mode optical fiber. In contrast, the spectroscopy (fluorescence and gain spectrum) of the Nd(3+) ions is dramatically changed by the ceramming process, an indication of strong partitioning of the rare-earth ions into the CdF(2):PbF(2):YF(3) crystal environment. The enormous potential for a new range of optical devices based on transparent glass-ceramic materials is highlighted.

Summary form only given. Glass-ceramics are two-phase systems consisting of a base glass within which crystals are grown by heat treatment, a process known as ceramming. Recent progress on fiberization of these materials led to the demonstration of a rare earth doped fiber laser and amplifier with an efficiency uncompromised by the presence of the crystals embedded within the core of the single mode fiber. Transitions metal ions are notoriously inefficient when incorporated into a glass host, due to the difficulty of controlling the local environment, to which they are very sensitive. However to date, the properties of Cr/sup 4+/-doped glass-ceramic systems have received little attention, despite the apparent advantages of crystal site control. This paper investigates the fluorescence properties of Cr/sup 4+/-doped forsterite glass-ceramics and shows that many of the important characteristics of the single crystal are reproduced in the glass-ceramic system. Furthermore, many of the spectroscopic parameters are also observed in glass-ceramic fiber, highlighting the potential for a new class of fiber laser and amplifier made from transition metal-doped glass-ceramics.

Pr amplifier gain efficiencies for different glass hosts and loss coefficients are compared. The gain bandwidth of a sulfide-based amplifier is limited by bottlenecking in the lower level H-3(5), but can be improved by adding a second pump resonant with the H-3(5)-(1)G(4) transition. A hybrid sulfide/fluoride amplifier also improves the bandwidth, and gives a remarkably flat gain spectrum from 1300-1350 nm.

Summary form only given. It has recently been shown that it is possible to make glass-ceramic single-mode optical fibers without significantly increasing the scattering loss, despite the presence of small (typically <10-nm diameter) crystals embedded within the core of the single-mode optical fiber. Furthermore the strong partitioning of rare-earth ions into the crystalline phase opens up the attractive possibility of combining the spectroscopic properties of rare-earth-doped crystals with the robustness of glass fiber technology. The optical fibers used are made by a double crucible technique from glasses with compositions containing, 30SiO/sub 2/-15AlO/sub 3/2/-29CdF/sub 2/-17PbF/sub 2/-4YF/sub 3/ and were doped with 500-ppm NdF/sub 3/. The fiber core diameter is around 5 micron.

Summary form only given.Low phonon energy sulfide glasses show promise as a potential host for an efficient Pr doped fiber amplifier, operating in the second telecommunications window at 1.3 /spl mu/m. The high efficiency arises from a combination of higher radiative rates and reduced nonradiative relaxation rates in these glasses, which reduces the nonradiative quenching of the upper laser level (/sup 1/G/sub 4/). However, it has recently been shown that the low nonradiative relaxation rates in these glasses also have the detrimental effect of increasing the lifetime of the lower laser level (/sup 3/H/sub 5/), which leads to bottle-necking of the population in the /sup 3/H/sub 5/, and a reduction of gain at shorter wavelengths. In this work we show that this bottle-necking can be partially alleviated by adding a second pump on the short wavelength side of the /sup 3/H/sub 5/-/sup 1/G/sub 4/ transition.

Infrared emission at 1.2, 1.25, 1.67, 2.0, 2.2, 2.9, 3.9, and 4.9 mu m is measured in holmium (Ho3+) doped gallium lanthanum sulphide (GLS) glass. Branching ratios, radiative quantum efficiencies, and emission cross-sections are calculated from lifetime, absorption, and emission measurements using Judd-Ofelt analysis and the Fuchtbauer-Ladenburg equation. The fluorescence band at 3.9 mu m coincides with an atmospheric transmission window and the fluorescence band at 4.9 mu m overlaps with the fundamental absorption of carbon monoxide, making the glass a potential fibre laser source for remote sensing and gas sensing applications. This is the first time this latter transition has been reported in any holmium doped host. (C) 1999 Elsevier Science B.V. All rights reserved.

Infrared emission at 0.7, 0.8, 1.2, 1.5, 1.8, 2.3, 3.8, and 4.8 mu m is measured in thulium- (Tm3+) and terbium(Tb3+) doped gallium lanthanum sulfide (GLS) glass. Emission cross sections are calculated from the absorption and emission spectra by use of Judd-Ofelt analysis, the Fuchtbauer-Ladenburg equation, and the theory of McCumber. Fluorescence and lifetime measurements confirm energy transfer from Tm3+ to Tb3+ ions and reveal a number of new cross-relaxation and upconversion processes between Tm3+ ions involving the F-3(2,3) and H-3(5) levels that can be observed only in low-phonon-energy materials. These processes indicate that the most efficient pump wavelength for the 1.2- and 3.8-mu m transitions is 0.7 mu m. The Tm3+ fluorescence at 3.8 mu m coincides with an atmospheric transmission window, and the Tb3+ fluorescence at 4.8 mu m overlaps the fundamental absorption of carbon monoxide, making the glass a potential fiber laser source for remote-sensing and gas-sensing applications. (C) 1999 Optical Society of America [S0740-3224(99)01902-5].