Destructive Phase Research Articles

On the study of wavy leading-edge vanes to achieve low fan interaction noise

The application of wavy leading-edge vanes to reduce a single-stage axial fan noise is numerically studied. The aerodynamic and acoustic performance of the fan is numerically investigated using a hybrid unsteady Reynolds averaged Navier-Stokes (URANS)/acoustic analogy method (Goldstein equations). First, the hybrid URANS/Goldstein method is developed and successfully validated against experiment results. Next, numerical simulations are performed to investigate the noise reduction effects of the wavy leading-edge vanes. The aerodynamic and acoustic performance is assessed for a fan with vanes equipped with two different wavy leading-edge profiles and compared with the performance of conventional straight leading-edge vanes. Results indicate that a fan with wavy leading-edge vanes produces lower interaction noise than the baseline fan without a significant loss in aerodynamic performance. In fact, it is demonstrated that wavy leading-edge vanes have the potential to lead to both aerodynamic and acoustic improvements. The two different wavy leading-edge profiles are shown to successfully reduce the fan tone sound power level by 1.2 dB and 4.3 dB, respectively. Fan efficiency is also improved by about 1% with one of the tested wavy leading-edge profiles. Large eddy simulation (LES) is also performed for a simplified fan stage model to assess the effects of wavy leading-edge vanes on the broadband fan noise. Results indicate that the overall sound power level of a fan can be reduced by about 4 dB with the larger wavy leading-edge profile. Finally, the noise reduction mechanisms are investigated and analysed. It is found that the wavy leading-edge profiles can induce significant streamwise vorticity around the leading-edge protuberances and reduce pressure fluctuations (especially at locations of wavy leading-edge hills) and unsteady forces on the stator vanes. The underlying mechanism of the reduced pressure fluctuations is also discussed by examining the magnitude-squared coherence between the velocity and pressure fluctuations in the vicinity of the noise sources. Moreover, a reduction in the correlation level of the wall pressure fluctuations along the vane leading-edge is observed, as well as destructive phase interference along the vane leading-edge.

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Nonstationary Stimulated Raman Scattering by Polaritons in Continuum of Dipole-Active Phonons

The system of equations simulating the processes of nonstationary stimulated Raman scattering (SRS) with the excitation of polar optical phonons is obtained. This system is found by applying such standard methods as the nonstationary theory of perturbations, which resulted in the equations for the amplitudes of probabilities to find the discrete system in certain state, and slowly-varying amplitudes for the electromagnetic waves. It has been shown that the obtained system includes, as extremes, the case of classical interaction between electromagnetic field and resonant medium (including the “area theorem”), and the one related with SRS on optical phonons. We have conducted both theoretical and numerical investigation of simplified system assuming that the amplitudes of all electromagnetic waves (laser, Stokes, and polariton) were real (there was no destructive spatial-temporal phase modulation). Only low-order nonlinear processes are considered. It is shown that this system can be reduced to Sine-Gordon equation. This system can also be simplified to the equation that simulates the motion of physical pendulum from upper equilibrium position. The numerical study of nonstationary SRS when the electromagnetic field of laser radiation and Stokes excite both polariton emission and the continuum of dipole-active phonons has been carried out. The evolution of the intensity of the polariton wave as function of the length of nonlinear medium has been numerically analyzed.

Ultra-Wideband Low-RCS Circularly-Polarized Metasurface-Based Array Antenna Using Tightly-Coupled Anisotropic Element

A novel broadband circular-polarized array antenna with ultra-wideband low radar cross section (RCS) is proposed. The array is made up of $2\times2$ identically circular-polarized sub-arrays in a chessboard configuration. Furthermore, each sub-array consists of $2\times2$ tightly coupled metasurface-based elements with linear polarization. For radiation, each element is excited and fed with 90° phase shift between adjacent ones to perform broadband circular-polarized operation. For scattering, destructive phase difference is created in an ultra-wide band for orthogonally polarized incidence due to the anisotropic structure. Thus, a considerable ultra-wideband RCS reduction involving in-band and out-of-band is achieved based on energy cancellation. By this means, broadband circular-polarized radiation and ultra-wideband low RCS performance can be achieved in a synthesized design process. The prototype is fabricated and measured. A good agreement between measured and simulated results verifies the validity of our design method.

Temporal expression of interleukin-22, interleukin-22 receptor 1 and interleukin-22-binding protein during experimental periodontitis in rats.

Interleukin-22 (IL-22), mainly produced by CD4+ T-helper subtypes and innate lymphoid cells at barrier surfaces, is found to involve in several diseases, including diabetes, rheumatoid arthritis, peri-implantitis and chronic rhinosinusitis with nasal polyps. The purpose of this study was to investigate histological changes and the levels of interleukin-22, interleukin-22 receptor 1 (IL-22R1) and interleukin-22-binding protein (IL-22BP) in experimental periodontitis. Sixty male 8-week-old Sprague Dawley rats were randomly allocated to six groups of 10 rats each. In the periodontitis groups, experimental periodontitis was established and the rats were killed on days 3, 5, 7, 11 and 15 after ligation, while the rats without ligation were killed on day 0, representing the healthy control group (day 0 group). Histopathologic changes were detected by hematoxylin and eosin (H&E) staining, and alveolar bone loss was determined by micro-computed tomography (micro-CT). Tartrate-resistant acid phosphatase (TRAP) staining was used to investigate osteoclast formation. Real-time quantitative PCR (qPCR) and immunohistochemistry were used to investigate the expression and location of IL-22, IL-22R1 and IL-22BP in gingival tissues. H&E staining showed increasingly severe destruction of the epithelial layer between day 3 and day 7, and the hyperplasia of pocket epithelium and the formation of periodontal pockets could be detected from day 11 to day 15. Micro-CT indicated an exponential increase in alveolar bone loss from day 3 to day 11 (P<.01). Bone resorption tended to be stationary after this period. TRAP staining showed that the number of multinucleate osteoclasts peaked at day 3 (P<.001, compared with day 0) and decreased at subsequent time points between day 5 and day 15. IL-22BP was expressed strongly under steady-state conditions in epithelial cells. IL-22-positive cells could be clearly observed both in the epithelial layer and around the lamina propria, whereas IL-22R1 was mainly localized in the epithelial layer of the damage period. Real-time qPCR revealed up-regulation of IL-22 and IL-22R1, as well as down-regulation of IL-22BP in gingival tissues during the destructive phase of periodontitis. This study shows the expression and localization of IL-22, IL-22R1 and IL-22BP, as well as the relevant histopathological alterations during the development of experimental periodontitis.

On compensation of four wave mixing effect in dispersion managed hybrid WDM-OTDM multicast overlay system with optical phase conjugation modules

Abstract This paper investigated the effect of FWM and its suppression using optical phase conjugation modules in dispersion managed hybrid WDM-OTDM multicast overlay system. Interaction between propagating wavelength signals at higher power level causes new FWM component generation that can significant limit the system performance. OPC module consists of the pump signal and 0.6 km HNLF implemented in midway of optical link to generate destructive phase FWM components. Investigation revealed that by use of even OPC module in optical link reduces the FWM power and mitigate the interaction between wavelength signals at variable signal input power, dispersion parameter ( β 2 ) and transmission distance. System performance comparison is also made between without DM-OPC module, with DM and with DM-OPC module in scenario of FWM tolerance. The BER performance of hybrid WDM-OTDM multicast system using OPC module is improved by multiplication factor of 2 as comparable to dispersion managed and coverage distance is increased by factor of 2 as in Singh and Singh (2016).

Hot corrosion behaviour of nanostructured zirconia in molten NaVO3 salt

Plasma sprayed coatings were fabricated from nanostructured yttria-stabilized zirconia powders (n-YSZ) with different crystalline grain sizes, prepared via sintering of nano ZrO2-4 mol% Y2O3 powders at different temperatures. The hot corrosion behaviour of both n-YSZ powders and their corresponding coatings with sodium metavanadate (NaVO3) were investigated at 700 °C. During hot corrosion, NaVO3 reacts with Y2O3 in YSZ to form YVO4, leading to a tetragonal to monoclinic destructive phase transformation of YSZ. The crystalline grain size of n-YSZ powders did not affect the hot corrosion mechanisms of both the n-YSZ powders and their corresponding coatings. However, compared with n-YSZ powders, the coatings were more easily corroded, and the coatings formed from starting powders with crystalline grain sizes <30 nm featured better degradation resistance to hot corrosion.

Isolation of Stem Cells and Progenitors from Mouse Epidermis.

The epidermis consists of several distinct compartments including the interfollicular epidermis (IFE), sweat glands, sebaceous glands (SGs), and the hair follicle (HF). While the IFE and SGs are in a constant state of self-renewal, the HF cycles between phases of growth, destruction, and rest. The hair follicle stem cells (HFSCs) that fuel this perpetual cycle have been well described and are located in a niche termed the bulge. These bulge SCs express markers such as CD34 and Keratin 15 (K15), enabling the isolation of these cells. Here, we describe a powerful method for isolating HFSCs and epidermal progenitors from mouse skin utilizing fluorescence activated cell-sorting (FACS). Upon isolation, cells can be expanded and utilized in various in vivo and in vitro models aimed at studying the function of these unique cells. © 2017 by John Wiley & Sons, Inc.

E-Cadherin–Mediated Cell Contact Controls the Epidermal Damage Response in Radiation Dermatitis

Radiotherapy is a primary oncological treatment modality that also damages normal tissue, including the skin, and causes radiation dermatitis (RD). Here, we explore the mechanism of acute epidermal damage in radiation dermatitis. Two distinctive phases in the damage response were identified: an early destructive phase, where a burst of reactive oxygen species induces loss of E-cadherin-mediated cell contact, followed by a regenerative phase, during which Wnt and Hippo signaling are activated. A blocking peptide, as well as a neutralizing antibody to E-cadherin, works synergistically with ionizing radiation to promote the epidermal damage. In addition, ROS disassembles adherens junctions in epithelial cells via posttranslational mechanisms, that is, activation of Src/Abl kinases and degradation of β-catenin/E-cadherin. The key role of tyrosine kinases in this process is further substantiated by the rescue effect of the tyrosine kinase inhibitor genistein, and the more specific Src/Abl kinase inhibitor dasatinib: both reduced ROS-induced degradation of β-catenin/E-cadherin invitro and ameliorated skin damage in rodent models. Finally, we confirm that the same key molecular events are also seen in human radiation dermatitis. Therefore, we propose that loss of cell contact in epidermal keratinocytes through reactive oxygen species-mediated disassembly of adherens junctions is pivotal for the acute epidermal damage in radiation dermatitis.

Aharonov-Bohm effect in monolayer phosphorene nanorings

This work presents theoretical demonstration of Aharonov-Bohm (AB) effect in monolayer phosphorene nanorings (PNR). Atomistic quantum transport simulations of PNR are employed to investigate the impact of multiple modulation sources on the sample conductance. In presence of a perpendicular magnetic field, we find that the conductance of both armchair and zigzag PNR oscillate periodically in a low-energy window as a manifestation of the AB effect. Our numerical results have revealed a giant magnetoresistance (MR) in zigzag PNR (with a maximum magnitude approaching two thousand percent). It is attributed to the AB effect induced destructive interference phase in a wide energy range below the bottom of the second subband. We also demonstrate that PNR conductance is highly anisotropic, offering an additional way to modulate MR. The giant MR in PNR is maintained at room temperature in the presence of thermal broadening effect.

Sediment trapping in deltas of small mountainous rivers of southwestern Taiwan and its influence on East China Sea sedimentation

Taiwan's setting of high mountains, steep gradients, frequent earthquakes, erodible lithology, and heavy rainfall represents an ideal site to focus on sedimentary processes of the deltas of small mountainous rivers (SMRs). Several SMRs in southwestern Taiwan have deposited a thick sedimentary succession in the composite Southwest Taiwan Delta (SWTD) since the middle Holocene. Evidence from the SWTD can help to determine its trapping efficiency and assess the role of SMRs in sediment transport to the sea. We used historical nautical charts, bathymetric data, satellite radar data, and 14C dates to calculate the sediment volume of the SWTD on millennial and decadal scales. The 14C dates of core samples indicate deposition of thick deltaic sediment in subsiding areas since the time of the maximum flooding surface about 7 cal ka BP. The paleo-shoreline changes of the SWTD suggest a steady westward progradation since 7 cal ka BP. In contrast, the nautical charts suggest minor volume reduction of the offshore part of the SWTD, with a deepening trend and retreating shorelines, during the last seven decades. The results show that at least 201.72 ± 13.90 km3 (∼3.23 × 105 Mt) of sediment has been trapped in the SWTD since 7 cal ka BP, and that the delta has shifted to a destructive phase during the past seven decades as human influences such as construction of reservoirs, dams, and weirs in the hills have reduced the sediment supply. The birth of the Taiwan Warm Current and following continuous sediment supply from the western rivers of Taiwan to the East China Sea since ∼7.3 cal ka BP have played a crucial role in the sedimentation of the East China Sea, particularly in the Okinawa Trough, and the Japan Sea through the Tsushima Warm Current.

Frequency-dependent fine structure in the frequency-following response: The byproduct of multiple generators

The frequency-following response (FFR) is an auditory-evoked response recorded at the scalp that captures the spectrotemporal properties of tonal stimuli. Previous investigations report that the amplitude of the FFR fluctuates as a function of stimulus frequency, a phenomenon thought to reflect multiple neural generators phase-locking to the stimulus with different response latencies. When phase-locked responses are offset by different latencies, constructive and destructive phase interferences emerge in the volume-conducted signals, culminating in an attenuation or amplification of the scalp-recorded response in a frequency-specific manner. Borrowing from the literature on the audiogram and otoacoustic emissions (OAEs), we refer to this frequency-specific waxing and waning of the FFR amplitude as fine structure. While prior work on the human FFR was limited by small sets of stimulus frequencies, here, we provide the first systematic investigation of FFR fine structure using a broad stimulus set (90 + frequencies) that spanned the limits of human pitch perception. Consistent with predictions, the magnitude of the FFR response varied systematically as a function of stimulus frequency between 16.35 and 880 Hz. In our dataset, FFR high points (local maxima) emerged at ∼44, 87, 208, and 415 Hz with FFR valleys (local minima) emerging ∼62, 110, 311, and 448 Hz. To investigate whether these amplitude fluctuations are the result of multiple neural generators with distinct latencies, we created a theoretical model of the FFR that included six putative generators. Based on the extant literature on the sources of the FFR, our model adopted latencies characteristic of the cochlear microphonic (0 ms), cochlear nucleus (∼1.25 ms), superior olive (∼3.7 ms), and inferior colliculus (∼5 ms). In addition, we included two longer latency putative generators (∼13 ms, and ∼25 ms) reflective of the characteristic latencies of primary and non-primary auditory cortical structures. Our model revealed that the FFR fine structure observed between 16.35 and 880 Hz can be explained by the phase-interaction patterns created by six generators with relative latencies spaced between 0 and 25 ms. In addition, our model provides confirmatory evidence that both subcortical and cortical structures are activated by low-frequency (<100 Hz) tones, with the cortex being less sensitive to frequencies > 100 Hz. Collectively, these findings highlight (1) that the FFR is a composite response; (2) that the FFR at any given frequency can reflect activity from multiple generators; (3) that the fine-structure pattern between 16.35 and 880 Hz is the collective outcome of short- and long-latency generators; (4) that FFR fine structure is epiphenomenal in that it reflects how volume-conducted electrical potentials originating from different sources with different latencies interact at scalp locations, not how these different sources actually interact in the brain; and (5) that as a byproduct of these phase-interaction patterns low-amplitude responses will emerge at some frequencies, even when the underlying generators are fully functioning. We believe these findings call for a re-examination of how FFR amplitude is interpreted in both clinical and experimental contexts.

The Acquarossa Memory Project: reconstructing an Etruscan town

Digital techniques and cultural heritage connect, in an innovative way, new and old within the Humanities. In this new project, an Etruscan townscape will be recreated; modelled results created by the 4D Research Lab will be integrated in an Archaeological Park and Museum in such a way that international scholars and visitors can acknowledge and study 3D reconstructions of a series of Etruscan houses within their successive phases of creation, function, reception, destruction, and reconstruction. Acquarossa is an Etruscan town near Viterbo, Italy. Excavations carried out by the Swedish Institute in Rome revealed a series of Etruscan houses, inhabited from the 8th century BC until the middle of the 6th century BC, when the town was suddenly and inexplicably abandoned. The houses were left to crumble and the remains of the foundations, the walls and the decorated roofs, as well as the thousands of household utensils, were all found in situ. It is one of the very few examples of an intact Etruscan townscape, with a unique set of family dwellings from the past. The remnants of the houses were partially reconstructed in the 1980s and covered with soil, but others were left to be destroyed by weather conditions. The site was left to vanish completely. Since 2014, the 4D Research Lab of the Faculty of Humanities of the University of Amsterdam has been involved in an interdisciplinary research project, in collaboration with the private partner Azienda Agrituristica Raffaele Rocchi, the proprietor of the site, which focuses on the reconstruction of a set of houses in annotated 3D models. The 3D models will be used to build ‘actual’ guesthouses at the site itself, for which permission from the Soprintendenza per i Beni archeologici del Lazio e dell’Etruria Meridionale has been granted. The project aims to analyse the house architecture, roof decoration and building processes through 3D modelling and scanning.

Ultrawideband and Polarization-Independent Radar-Cross-Sectional Reduction With Composite Artificial Magnetic Conductor Surface

A composite artificial magnetic conductor (AMC) surface has been proposed for ultrawideband and polarization-independent radar-cross-sectional (RCS) reduction. Three different AMC units are employed to form the composite surface, which make up of destructive phase difference (180° ± 30°) over a broad frequency range. It is analytically shown that an ultrawideband RCS reduction is achieved from 5.0 to 20.0 GHz for arbitrary polarizations. The RCS reduction value exceeds 10.0 dB almost from 6.0 to 18.4 GHz, resulting in a fractional bandwidth of 101.6%. To verify the proposed design method, the AMC surface specimen is fabricated and measured, and the experimental results agree well with the simulations.

Identification of blast resistance genes in 358 rice germplasms (Oryza sativa L.) using functional molecular markers

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most devastating diseases of rice (Oryza sativa L.), and neck blast is the most destructive phase of this disease. Although neck blast causes tremendous yield loss, little is known about the molecular mechanisms underlying the neck blast resistance. To address this issue, we collected 358 rice varieties from different ecotypes in China and assessed them for the neck blast resistance under natural conditions favoring disease development in Jining, Shandong Province. Our results showed that 124 (34.6%) and 234 (65.4%) varieties were resistant and susceptible to M. oryzae under natural field conditions, respectively. Among the 358 rice varieties that were screened for the presence of 13 major blast resistance (R) genes against M. oryzae by using functional markers, 259 varieties contained one to seven R genes. In addition, the relationship between the presence of R genes and the disease reactions was also investigated by integrative analysis of phenotyping and genotyping based on functional markers. Our results showed that the rice blast resistance gene Pi2 was significantly correlated with neck blast resistance. Furthermore, any of the 13 major blast R genes was absent from 32 rice varieties exhibited obvious neck blast resistance, which would be the potential materials for identifying novel neck blast R genes. Taken together, our findings provide insight into the distribution of the 13 major blast R genes in the tested Chinese rice germplasm resources, which will serve as a basis for developing rice blast resistant. Furthermore, 32 rice varieties exhibited neck blast resistance, but they did not harbor any of the 13 major blast R genes. In the future, these varieties may be used to identify novel neck blast R genes.

Regulation of matrix metalloproteinase secretion by green tea catechins in a three-dimensional co-culture model of macrophages and gingival fibroblasts

ObjectivesElevated levels of matrix metalloproteinases (MMPs) have been associated with the active phases of tissue and bone destruction in periodontitis, an inflammatory disease characterized by a significant breakdown of tooth support. In the present study, we used a three-dimensional (3D) co-culture model of macrophages and gingival fibroblasts to investigate the ability of a green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) to regulate the secretion of MMP-3, -8, and -9. MethodsThe 3D co-culture model was composed of gingival fibroblasts embedded in a type I collagen matrix overlaid with macrophages. Two arbitrary ratios were tested. The ratio composed of 1 macrophage to 10 fibroblasts was used to mimic a slightly inflamed periodontal site while the ratio composed of 10 macrophages to 1 fibroblast was used to mimic a severely inflamed periodontal site. The 3D co-culture model was pre-treated for 2h with either the green tea extract or EGCG. It was then stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS). The model was also first stimulated with LPS for 2h and then incubated with the green tea extract or EGCG. The concentrations of secreted MMP-3, -8, and -9 were quantified by enzyme-linked immunoassays. ResultsWhen the 3D co-culture model was stimulated with A. actinomycetemcomitans LPS, the 10:1 ratio of macrophages to gingival fibroblasts was associated with a highest secretion of MMP-3 and -9 and, to a lesser extent, MMP-8, than the 1:10 ratio. Non-cytotoxic concentrations of the green tea extract or EGCG reduced the basal secretion levels of all three MMPs. A 2-h treatment with the green tea extract or EGCG prior to the stimulation with LPS resulted in a dose-dependent decrease in MMP secretion, with MMP-9 showing the most significant decrease. A decrease in MMP secretion was also observed when the green tea extract or EGCG was added following a 2-h stimulation with LPS. ConclusionsOur results suggested that green tea catechins, and more specifically EGCG, offer promising prospects for the development of a novel adjunctive treatment for periodontitis because of their ability to decrease the secretion of MMPs, which are important tissue-destructive enzymes produced by mucosal and immune cells.

Overlapping toxic effect of long term thallium exposure on white mustard (Sinapis alba L.) photosynthetic activity.

BackgroundHeavy metal exposure affect plant productivity by interfering, directly and indirectly, with photosynthetic reactions. The toxic effect of heavy metals on photosynthetic reactions has been reported in wide-ranging studies, however there is paucity of data in the literature concerning thallium (Tl) toxicity. Thallium is ubiquitous natural trace element and is considered the most toxic of heavy metals; however, some plant species, such as white mustard (Sinapis alba L.) are able to accumulate thallium at very high concentrations. In this study we identified the main sites of the photosynthetic process inhibited either directly or indirectly by thallium, and elucidated possible detoxification mechanisms in S. alba.ResultsWe studied the toxicity of thallium in white mustard (S. alba) growing plants and demonstrated that tolerance of plants to thallium (the root test) decreased with the increasing Tl(I) ions concentration in culture media. The root growth of plants exposed to Tl at 100 μg L−1 for 4 weeks was similar to that in control plants, while in plants grown with Tl at 1,000 μg L−1 root growth was strongly inhibited. In leaves, toxic effect became gradually visible in response to increasing concentration of Tl (100 − 1,000 μg L−1) with discoloration spreading around main vascular bundles of the leaf blade; whereas leaf margins remained green. Subsequent structural analyses using chlorophyll fluorescence, microscopy, and pigment and protein analysis have revealed different effects of varying Tl concentrations on leaf tissue. At lower concentration partial rearrangement of the photosynthetic complexes was observed without significant changes in the chloroplast structure and the pigment and protein levels. At higher concentrations, the decrease of PSI and PSII quantum yields and massive oxidation of pigments was observed in discolored leaf areas, which contained high amount of Tl. Substantial decline of the photosystem core proteins and disorder of the photosynthetic complexes were responsible for disappearance of the chloroplast grana.ConclusionsBased on the presented results we postulate two phases of thallium toxicity on photosynthesis: the non-destructive phase at early stages of toxicant accumulation and the destructive phase that is restricted to the discolored leaf areas containing high toxicant content. There was no distinct border between the two phases of thallium toxicity in leaves and the degree of toxicity was proportional to the migration rate of the toxicant outside the vascular bundles. The three-fold (nearly linear) increase of Tl(I) concentration was observed in damaged tissue and the damage appears to be associated with the presence of the oxidized form of thallium − Tl(III).Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0883-4) contains supplementary material, which is available to authorized users.

Using a plenoptic sensor to reconstruct vortex phase structures.

A branch point problem and its solution commonly involve recognizing and reconstructing a vortex phase structure around a singular point. In laser beam propagation through random media, the destructive phase contributions from various parts of a vortex phase structure will cause a dark area in the center of the beam's intensity profile. This null of intensity can, in turn, prevent the vortex phase structure from being recognized. In this Letter, we show how to use a plenoptic sensor to transform the light field of a vortex beam so that a simple and direct reconstruction algorithm can be applied to reveal the vortex phase structure. As a result, we show that the plenoptic sensor is effective in detecting branch points and can be used to reconstruct phase distortion in a beam in a wide sense.

Rise and Fall of an Egyptian Oasis: Artesian Flow, Irrigation Soils, and Historical Agricultural Development in El‐Deir, Kharga Depression, Western Desert of Egypt

The present study examines the geoarchaeological history of an oasis in Kharga Depression in central Egypt. El‐Deir is renowned for its Ptolemaic temple and Roman fortress on the road from former Hibis (Kharga) to the Nile Valley. During the survey, spring mounds and irrigation soils belonging to an ancient agricultural zone were discovered, and further documented by ceramics found on the site. Our methodology combines the geomorphological interpretation of landforms (especially yardangs) with ceramics and 14C‐dated charcoal to distinguish and date former agricultural areas in El‐Deir. The results show that the oasis experienced several phases of soil accretion and destruction through time. Playa sediments were deposited in the humid early Holocene and severely eroded by deflation before the onset of irrigated agriculture between Pharaonic and Persian times. Very fast vertical soil accretion occurred in the Ptolemaic period, but irrigation soils were later destroyed during the Roman period by a combination of wind deflation and flash floods (second to fourth century A.D.), suggesting a period of climate instability. The case of El‐Deir invites reevaluation of constructive agencies for the development of irrigated land and destructive agencies as limiting factors for the sustainability of agricultural practices in late antiquity.

Copper(I) thiocyanate networks with aliphatic sulfide ligands

A total of five new CuSCN-L compounds with alkyl sulfide ligands, L=methyl sulfide (Me2S), ethyl sulfide (Et2S), isopropyl sulfide (Pri2S) or tetrahydrothiophene (THT) have been prepared and characterized. X-ray crystal structures for four of the compounds were obtained. Two compounds were collected from solutions of CuSCN in Me2S: {[Cu(SCN)(Me2S)2]}n (1a) in the form of colorless blocks and (CuSCN)(Me2S) (1b) as a white powder. Neat mixtures of CuSCN in the other alkyl sulfide ligands yielded only one product each: {[Cu(SCN)(Et2S)]}n (2); {[Cu(SCN)(Pri2S)]}n (3); and {[Cu(SCN)(THT)2]}n (4). Crystals of 2 and 4 underwent destructive phase changes at lower temperatures. Two networks types were observed: 1:2 decorated 1-D chains (1a and 4) and 1:2 decorated 1-D ladders (2 and 3). Further network formation through bridging of the organic sulfide ligands was not observed.