Part Of TM Research Articles

Effects of the Grapevine Biochar on the Properties of PLA Composites.

This study found that biochar made from grapevines (GVC), an agricultural waste product, can be used as a nucleating agent to promote the crystallization of polylactic acid (PLA). Differential scanning calorimetry (DSC) analysis of GVC/PLA composites showed that different particle sizes (200 and 100 mesh size) and amounts (1 wt%, 10 wt%) of biochar affect the re-crystallization of PLA, with 200 mesh GVC in the amount of 10 wt% being the most significant. In addition, it was found that there were two peaks related to imperfect and perfect crystals in the Tm part for GVC/PLA composites. TGA analysis showed that adding GVC tends to lower the maximum decomposition temperature of PLA, revealing that GVC may accelerate the degradation reaction of PLA. This research also studied the effects of GVC in various particle sizes and amounts on the mechanical properties and degradation of PLA. The results revealed that the tensile and impact strengths of GVC/PLA composite could reach 79.79 MPa and 22.67 J/m, respectively, and the increments were 41.4% and 32.1%, greater than those of pristine PLA. Moreover, the molecular weight of PLA decreased as the amount of GVC increased. Therefore, GVC particles can be used as reinforcing fillers for PLA to improve its mechanical properties and adjust its molecular weight. These agricultural-waste-reinforced biocomposites can reduce both greenhouse gas (GHG) emissions and the cost of biodegradable polymers and achieve the goals of a circular economy.

Game Framework Analysis and Cognitive Learning Theory Providing a Theoretical Foundation for Efficacy in Learning in Educational Gaming

Several meta-analyses and studies have been undertaken in game-based research, which compare the efficacy of conventional teaching against the introduction of educational games into the classroom. The findings point to educational gaming providing teaching approach that allows for improved efficacy in learning and deeper conceptual understanding. But there is a paucity of research in terms of explaining ‘how’ and ‘why’ students learn from games. The mapping out the students’ experiences of learning, as a result of an economics gaming intervention, was achieved using research methodology called Interactive Qualitative Analysis (IQA). The findings of the IQA process were then further refined and developed into Game Framework Analysis (GAF) model which points to games providing a learning system that allows for deeper conceptualization of concepts and more meaningful application of knowledge. The question that arose was ‘How could this be possible?’ Part of the answer is provided by Cognitive Load Theory (CLT) which was developed by Sweller (1988). CLT examines the management of working memory in learning contexts and the resultant effects on learning. Games were found to have in their DNA, the ability to create complex learning environments that can manage the cognitive load in a way that facilitates an optimal usage of working memory, resulting in effective learning. https://doi.org/10.26803/ijlter.19.7.9

Assessing precipitation concentration in the Amazon basin from different satellite‐based data sets

Daily precipitation concentration in the Amazon basin (AB) is characterized using concentration index (CI), which is computed from HYBAM Observed Precipitation (HOP) data set, for 1980–2009 period. The ability of four satellite precipitation data sets (TMPA V7, TMPA RT, CMORPH and PERSIANN) to estimate CI is evaluated for 2001–2009 period. Our findings provide new information about the spatial irregularity of daily rainfall distribution over the AB. In addition, the spatial distribution of CI values is not completely explained by rainfall seasonality, which highlights the influence of different weather systems over the AB. The results of rainfall concentration indicate that the distribution of daily rainfall is more regular over northwest (northern Peru) and central Andes. Conversely, Roraima region and a large area of Bolivian Amazon register the highest irregularity in the daily rainfall. Bolivian Amazon also represents regions where the large percentage of total rainfall arises from extreme events (>90th percentile). Heavy rainfall episodes over Roraima region are induced by humidity influx come from Caribbean region, while heavy rainfall events over Bolivian Amazon and Andes region are induced by the northwards propagation of cold and dry air along both sides of Andes Mountains, but only propagate in all tropospheric levels for the Andes. The results also show that PERSIANN and TMPA7 data sets better estimates the daily precipitation concentration for whole AB, but with a relative error 8%. CI estimated from satellites does not agree well with HOP over the Andes and northern Peruvian Amazon. On the other hand, the temporal variability of CI can partly be detected using CMORPH and TMPAV7 data sets over the Peruvian Andes, and central and southern Brazil. Errors in CI estimating might be related to inaccurate estimation of daily rainfall. Finally, we conclude that satellite‐based precipitation data sets are useful for analysing rainfall concentration in some regions of AB.

Consistency of satellite-based precipitation products in space and over time compared with gauge observations and snow- hydrological modelling in the Lake Titicaca region

Abstract. This paper proposes a protocol to assess the space–time consistency of 12 satellite-based precipitation products (SPPs) according to various indicators, including (i) direct comparison of SPPs with 72 precipitation gauges; (ii) sensitivity of streamflow modelling to SPPs at the outlet of four basins; and (iii) the sensitivity of distributed snow models to SPPs using a MODIS snow product as reference in an unmonitored mountainous area. The protocol was applied successively to four different time windows (2000–2004, 2004–2008, 2008–2012 and 2000–2012) to account for the space–time variability of the SPPs and to a large dataset composed of 12 SPPs (CMORPH–RAW v.1, CMORPH–CRT v.1, CMORPH–BLD v.1, CHIRP v.2, CHIRPS v.2, GSMaP v.6, MSWEP v.2.1, PERSIANN, PERSIANN–CDR, TMPA–RT v.7, TMPA–Adj v.7 and SM2Rain–CCI v.2), an unprecedented comparison. The aim of using different space scales and timescales and indicators was to evaluate whether the efficiency of SPPs varies with the method of assessment, time window and location. Results revealed very high discrepancies between SPPs. Compared to precipitation gauge observations, some SPPs (CMORPH–RAW v.1, CMORPH–CRT v.1, GSMaP v.6, PERSIANN, and TMPA–RT v.7) are unable to estimate regional precipitation, whereas the others (CHIRP v.2, CHIRPS v.2, CMORPH–BLD v.1, MSWEP v.2.1, PERSIANN–CDR, and TMPA–Adj v.7) produce a realistic representation despite recurrent spatial limitation over regions with contrasted emissivity, temperature and orography. In 9 out of 10 of the cases studied, streamflow was more realistically simulated when SPPs were used as forcing precipitation data rather than precipitation derived from the available precipitation gauge networks, whereas the SPP's ability to reproduce the duration of MODIS-based snow cover resulted in poorer simulations than simulation using available precipitation gauges. Interestingly, the potential of the SPPs varied significantly when they were used to reproduce gauge precipitation estimates, streamflow observations or snow cover duration and depending on the time window considered. SPPs thus produce space–time errors that cannot be assessed when a single indicator and/or time window is used, underlining the importance of carefully considering their space–time consistency before using them for hydro-climatic studies. Among all the SPPs assessed, MSWEP v.2.1 showed the highest space–time accuracy and consistency in reproducing gauge precipitation estimates, streamflow and snow cover duration.

Hybrid Renewable Energy System with Storage for Electrification – Case Study of Remote Northern Community in Canada

This paper’s primary objective constitutes addressing accessibility to modern energy as well as examining alternatives for diminishing petroleum derivative independency upon production of electricity for both underserved communities and remote northern populaces that are influenced by the negative effects of climatic changes heavily; an example here is Ontario, Canada’s Red Lake, which is Canadian isolated northern populations’ part. Accordingly, the execution of this microgrid advances improved well-being care as well as instruction while ensuring the green ecological factor in order to battle conditions of global warming within Ontario’s energy sector. Additionally, the electrification is needed to support the isolated communities as well as the nation to accomplish increasingly swift viable and societal goals. This investigation is carried out utilising the Hybrid Optimization Model for Electric Renewables tool referred to as HOMER . Various simulations with different setups were examined. It has been discovered that the microgrid with the utilisation of numerous sustainable power sources blend delivers an optimum result.

Assessing the performance of the Tao-Mo semilocal density functional in the projector-augmented-wave method.

We assess the performance of the recently proposed Tao-Mo (TM) semilocal exchange-correlation functional [J. Tao and Y. Mo, Phys. Rev. Lett. 117, 073001 (2016)] using the projector-augmented-wave method with the plane wave basis set. The meta-generalized gradient approximation level semilocal functional constructed by Tao-Mo is an all-purpose exchange-correlation functional for the quantum chemistry and solid-state physics. The exchange of the TM functional is based on the density matrix expansion technique together with the slowly varying fourth order gradient expansion. The correlation functional corresponding to the exchange is based on the one-electron self-interaction-free Tao-Perdew-Staroverov-Scuseria functional. Our test includes solid-state lattice constants, bulk moduli, bandgaps, cohesive energies, magnetic moments and vacancy-formation energies of transition metals. It is observed that in the plane wave basis, the TM functional performs accurately in predicting all the solid state properties at the semilocal level.

Hydrological modeling of the Peruvian-Ecuadorian Amazon basin using GPM-IMERG satellite-based precipitation dataset.

In the last two decades, rainfall estimates provided by the Tropical Rainfall Measurement Mission (TRMM) have proven applicable in hydrological studies. The Global Precipitation Measurement (GPM) mission, which provides the new generation of rainfall estimates, is now considered a global successor to TRMM. The usefulness of GPM data in hydrological applications, however, has not yet been evaluated over the Andean and Amazonian regions. This study uses GPM data provided by the Integrated Multi-satellite Retrievals (IMERG) (product/final run) as input to a distributed hydrological model for the Amazon Basin of Peru and Ecuador for a 16-month period (from March 2014 to June 2015) when all datasets are available. TRMM products (TMPA V7, TMPA RT datasets) and a gridded precipitation dataset processed from observed rainfall are used for comparison. The results indicate that precipitation data derived from GPM-IMERG correspond more closely to TMPA V7 than TMPA RT datasets, but both GPM-IMERG and TMPA V7 precipitation data tend to overestimate, compared to observed rainfall (by 11.1% and 15.7 %, respectively). In general, GPM-IMERG, TMPA V7 and TMPA RT correlate with observed rainfall, with a similar number of rain events correctly detected (~20%). Statistical analysis of modeled streamflows indicates that GPM-IMERG is as useful as TMPA V7 or TMPA RT datasets in southern regions (Ucayali basin). GPM-IMERG, TMPA V7 and TMPA RT do not properly simulate streamflows in northern regions (Marañón and Napo basins), probably because of the lack of adequate rainfall estimates in northern Peru and the Ecuadorian Amazon.

The Relaxation Properties of Myofibrils Are Compromised by Amino Acids that Stabilize α-Tropomyosin

We investigated the functional impact of α-tropomyosin (Tm) substituted with one (D137L) or two (D137L/G126R) stabilizing amino acid substitutions on the mechanical behavior of rabbit psoas skeletal myofibrils by replacing endogenous Tm and troponin (Tn) with recombinant Tm mutants and purified skeletal Tn. Force recordings from myofibrils (15°C) at saturating [Ca2+] showed that Tm-stabilizing substitutions did not significantly affect the maximal isometric tension and the rates of force activation (kACT) and redevelopment (kTR). However, a clear effect was observed on force relaxation: myofibrils with D137L/G126R or D137L Tm showed prolonged durations of the slow phase of relaxation and decreased rates of the fast phase. Both Tm-stabilizing substitutions strongly decreased the slack sarcomere length (SL) at submaximal activating [Ca2+] and increased the steepness of the SL-passive tension relation. These effects were reversed by addition of 10 mM 2,3-butanedione 2-monoxime. Myofibrils also showed an apparent increase in Ca2+ sensitivity. Measurements of myofibrillar ATPase activity in the absence of Ca2+ showed a significant increase in the presence of these Tms, indicating that single and double stabilizing substitutions compromise the full inhibition of contraction in the relaxed state. These data can be understood with the three-state (blocked-closed-open) theory of muscle regulation, according to which the mutations increase the contribution of the active open state in the absence of Ca2+ (M−). Force measurements on myofibrils substituted with C-terminal truncated TnI showed similar compromised relaxation effects, indicating the importance of TnI-Tm interactions in maintaining the blocked state. It appears that reducing the flexibility of native Tm coiled-coil structure decreases the optimum interactions of the central part of Tm with the C-terminal region of TnI. This results in a shift away from the blocked state, allowing myosin binding and activity in the absence of Ca2+. This work provides a basis for understanding the effects of disease-producing mutations in muscle proteins.

Structural and functional effects of two stabilizing substitutions, D137L and G126R, in the middle part of α‐tropomyosin molecule

Tropomyosin (Tm) is an α-helical coiled-coil protein that binds along the length of actin filament and plays an essential role in the regulation of muscle contraction. There are two highly conserved non-canonical residues in the middle part of the Tm molecule, Asp137 and Gly126, which are thought to impart conformational instability (flexibility) to this region of Tm which is considered crucial for its regulatory functions. It was shown previously that replacement of these residues by canonical ones (Leu substitution for Asp137 and Arg substitution for Gly126) results in stabilization of the coiled-coil in the middle of Tm and affects its regulatory function. Here we employed various methods to compare structural and functional features of Tm mutants carrying stabilizing substitutions Arg137Leu and Gly126Arg. Moreover, we for the first time analyzed the properties of Tm carrying both these substitutions within the same molecule. The results show that both substitutions similarly stabilize the Tm coiled-coil structure, and their combined action leads to further significant stabilization of the Tm molecule. This stabilization not only enhances maximal sliding velocity of regulated actin filaments in the in vitro motility assay at high Ca(2+) concentrations but also increases Ca(2+) sensitivity of the actin-myosin interaction underlying this sliding. We propose that the effects of these substitutions on the Ca(2+)-regulated actin-myosin interaction can be accounted for not only by decreased flexibility of actin-bound Tm but also by their influence on the interactions between the middle part of Tm and certain sites of the myosin head.

Stabilization of the Central Part of Tropomyosin Molecule Alters the Ca 2+-sensitivity of Actin-Myosin Interaction

We show that the mutations D137L and G126R, which stabilize the central part of the tropomyosin (Tm) molecule, increase both the maximal sliding velocity of the regulated actin filaments in the in vitro motility assay at high Са(2+) concentrations and the Са(2+)-sensitivity of the actin-myosin interaction underlying this sliding. Based on an analysis of the recently published data on the structure of the actin-Tm-myosin complex, we suppose that the physiological effects of these mutations in Tm can be accounted for by their influence on the interactions between the central part of Tm and certain sites of the myosin head.

Telemedicine: Current status and prospects in type 2 diabetes

Summary There has been rapid growth in studies involving TM in diabetes treatment in recent years. In France, while TM has proven its efficacy in DT1, there have been relatively few trials in T2D. Nevertheless, certain studies in the US have already shown benefits in terms of metabolic parameters compared with especially conventional treatment, which, in view of the high number of patients in a position to derive benefit, opens up broad new vistas. However, TM will only spread successfully on a national level through the concerted efforts of the various actors involved in its implementation. As regards the authorities, while a desire has been expressed to deploy TM nationally in five designated priority areas, its widespread use in diabetes therapy will depend upon the level of reimbursement agreed by the Health Insurance Department, and upon the costs to patients, but also on the perceived value of telephone consultations in terms of activity charges for hospitals and within the ambit of private practice. As regards health establishments, the spread of TM requires some reorganisation of healthcare, calling for intervention by paramedical staff acting by medical delegation in a context of inter-professional cooperation protocols. Such spread will thus depend upon the ability of firms developing medical devices to ensure compatibility of the information systems used. However, truly effective, implementation will depend first and foremost upon users themselves, in other words patients and healthcare teams, which means that each and every person must overcome their own resistance to change, to integrating TM devices and to making TM part of their daily lives as an effective instrument with which to optimise healthcare.

Conserved Noncanonical Residue Gly-126 Confers Instability to the Middle Part of the Tropomyosin Molecule

Tropomyosin (Tm) is a two-stranded α-helical coiled-coil protein with a well established role in regulation of actin cytoskeleton and muscle contraction. It is believed that many Tm functions are enabled by its flexibility whose nature has not been completely understood. We hypothesized that the well conserved non-canonical residue Gly-126 causes local destabilization of Tm. To test this, we substituted Gly-126 in skeletal muscle α-Tm either with an Ala residue, which should stabilize the Tm α-helix, or with an Arg residue, which is expected to stabilize both α-helix and coiled-coil structure of Tm. We have shown that both mutations dramatically reduce the rate of Tm proteolysis by trypsin at Asp-133. Differential scanning calorimetry was used for detailed investigation of thermal unfolding of the Tm mutants, both free in solution and bound to F-actin. It was shown that a significant part of wild type Tm unfolds in a non-cooperative manner at low temperature, and both mutations confer cooperativity to this part of the Tm molecule. The size of the flexible middle part of Tm is estimated to be 60-70 amino acid residues, about a quarter of the Tm molecule. Thus, our results show that flexibility is unevenly distributed in the Tm molecule and achieves the highest extent in its middle part. We conclude that the highly conserved Gly-126, acting in concert with the previously identified non-canonical Asp-137, destabilizes the middle part of Tm, resulting in a more flexible region that is important for Tm function.

Structure of a Double Transmembrane Fragment of a G-Protein-Coupled Receptor in Micelles

The structure and dynamic properties of an 80-residue fragment of Ste2p, the G-protein-coupled receptor for α-factor of Saccharomyces cerevisiae, was studied in LPPG micelles with the use of solution NMR spectroscopy. The fragment Ste2p(G31-T110) (TM1-TM2) consisted of 19 residues from the N-terminal domain, the first TM helix (TM1), the first cytoplasmic loop, the second TM helix (TM2), and seven residues from the first extracellular loop. Multidimensional NMR experiments on [15N], [15N, 13C], [15N, 13C, 2H]-labeled TM1-TM2 and on protein fragments selectively labeled at specific amino acid residues or protonated at selected methyl groups resulted in >95% assignment of backbone and side-chain nuclei. The NMR investigation revealed the secondary structure of specific residues of TM1-TM2. TALOS constraints and NOE connectivities were used to calculate a structure for TM1-TM2 that was highlighted by the presence of three α-helices encompassing residues 39–47, 49–72, and 80–103, with higher flexibility around the internal Arg58 site of TM1. RMSD values of individually superimposed helical segments 39–47, 49–72, and 80–103 were 0.25 ± 0.10 Å, 0.40 ± 0.13 Å, and 0.57 ± 0.19 Å, respectively. Several long-range interhelical connectivities supported the folding of TM1-TM2 into a tertiary structure typified by a crossed helix that splays apart toward the extracellular regions and contains considerable flexibility in the G56VRSG60 region. 15N-relaxation and hydrogen-deuterium exchange data support a stable fold for the TM parts of TM1-TM2, whereas the solvent-exposed segments are more flexible. The NMR structure is consistent with the results of biochemical experiments that identified the ligand-binding site within this region of the receptor.

Structurally Unstable Regions in the Tropomyosin-Troponin Complex from Bovine Heart Muscle

Regulation of contraction in striated muscles requires a semi-independent movement of various domains of the tropomyosin-troponin (TmTn) complex on the actin filament. Such movement is facilitated by the presence of flexible or structurally unstable regions in these proteins. In particular, it is well documented that the central part of tropomyosin comprises a region that unfolds readily at physiological temperatures. To identify flexible regions in the native TmTn complex isolated from bovine heart muscle, we have used limited proteolysis with Staphylococcus aureus V8 protease that cleaves specifically the peptide bond on the C-terminal side of Glu. At 4°C only troponin T and troponin I are digested at positions 59 and 166, respectively. At 35°C Tm is also digested, initially at position 145, followed by a rapid digestion at positions 142,131 and 150. The resulting two fragments of Tm spanning residues 1-131 (2x14.9 kDa) and 151-284 (2x15.5 kDa) are resistant to further digestion in the presence of troponin, which indicates that they retain their coiled-coil structure. However, in the absence of Tn the C-terminal fragment of Tm undergoes further proteolysis. The troponin C component of the complex is resistant to proteolysis under the conditions used. The two Tm fragments, together with TnC, the N-terminal fragment of TnI (residues 1-166) and the C-terminal fragment of TnT (residues 60-284) form a 125 kDa complex that is stable at low salt concentrations, binds to F-actin irrespective of calcium, and imparts significant calcium-dependent regulation to actomyosin ATPase. These results demonstrate that the central segment of Tm spanning residues 131-151 is structurally unstable irrespective of the presence of troponin and it structure stabilizing effect on the C-terminal part of Tm.

Effective Optical Constant of Alumina Particle Containing Carbon

a = radius of inner core, m b = radius of outer concentric shell, m fc = volume fraction of carbon fAl2O3 = volume fraction of alumina k = imaginary part of the complex refractive index (absorption index) m = mixture’s effective complex refractive index mAl2O3 = complex refractive index of alumina mc = complex refractive index of carbon n = real part of complex refractive index Tm = melting temperature of alumina particle, K = free parameter = mixture’s effective dielectric constant c = dielectric constant of carbon Al2O3 = dielectric constant of alumina = wavelength, m

Identification of ET A and ET B binding domains using ET-derived photoprobes

Using the structure of ET-1 as a template, a series of photosensitive analogs were developed to investigate the binding domain of ET A and ET B receptors. Accordingly, a p-benzoyl- l-phenylalanine (Bpa) residue was introduced into the peptide chain following a pattern aiming at scanning N- to C-terminal portions of the molecule. Among the analogs, those containing a Bpa amino acid in position 7 ([L-Bpa 7, Tyr( 125I) 13]hET-1) or 12 ([Nle 7, L-Bpa 12, Tyr( 125I) 13]hET-1) exhibited the capacity to activate both receptors, thus showing that residues Met-7 and Val-12 of ET-1 do not play a key role in the activation process. The binding capacity of the probes was also evaluated on transfected CHO cells overexpressing either ET A or ET B receptors. Subsequently, these photoprobes were used to label ET A and ET B receptors overexpressed in transfected CHO cells. Enzymatic digestions and chemical cleavages were then performed on ligand-receptor complexes and fragments produced by the lysis were analyzed to point out putative interaction areas on the receptors. Results showed that Phe 147–Lys 166, covering the second segment of EC I and the top part of TM III, contains a contact point for [Nle 7, L-Bpa 12, Tyr( 125I) 13]hET-1 on ET A receptors whereas Ile 292–Trp 319, spanning from the second half of the intracellular loop III up to the middle turns of TM VI, includes a residue that can interact with [L-Bpa 7, Tyr( 125I) 13]hET-1. Moreover, upon binding of [Nle 7, L-Bpa 12, Tyr( 125I) 13]hET-1, it was observed that Thr 263–Met 266 (EC II) of the ET B receptor would come close with the ligand.

Thermal unfolding of smooth muscle and nonmuscle tropomyosin α‐homodimers with alternatively spliced exons

We used differential scanning calorimetry (DSC) and circular dichroism (CD) to investigate thermal unfolding of recombinant fibroblast isoforms of alpha-tropomyosin (Tm) in comparison with that of smooth muscle Tm. These two nonmuscle Tm isoforms 5a and 5b differ internally only by exons 6b/6a, and they both differ from smooth muscle Tm by the N-terminal exon 1b which replaces the muscle-specific exons 1a and 2a. We show that the presence of exon 1b dramatically decreases the measurable calorimetric enthalpy of the thermal unfolding of Tm observed with DSC, although it has no influence on the alpha-helix content of Tm or on the end-to-end interaction between Tm dimers. The results suggest that a significant part of the molecule of fibroblast Tm (but not smooth muscle Tm) unfolds noncooperatively, with the enthalpy no longer visible in the cooperative thermal transitions measured. On the other hand, both DSC and CD studies show that replacement of muscle exons 1a and 2a by nonmuscle exon 1b not only increases the thermal stability of the N-terminal part of Tm, but also significantly stabilizes Tm by shifting the major thermal transition of Tm to higher temperature. Replacement of exon 6b by exon 6a leads to additional increase in the alpha-Tm thermal stability. Thus, our data show for the first time a significant difference in the thermal unfolding between muscle and nonmuscle alpha-Tm isoforms, and indicate that replacement of alternatively spliced exons alters the stability of the entire Tm molecule.

Generalized soft-and-hard surface

Soft-and-hard surface (SHS) is a mathematical idealization of the tuned corrugated boundary. The boundary conditions are defined by a single real vector parallel to the corrugations. The SHS boundary was recently generalized by replacing the real vector by a complex vector and its conjugate (see Lindell, I.V., Proc. Inst. Elect. Eng. Microw. Antenna Propagat., vol.147, p.495-9, 2000). The SHS boundary is generalized one step further by defining it in terms of two complex vectors tangential to the surface. It is shown that, analogous to the previous special cases, there exist two eigenpolarizations, TE and TM with respect to the two vectors for plane waves of any angle of incidence. These two specially polarized waves see the boundary as a simple perfect magnetic or electric conductor surface, respectively. Because the same is true for TE and TM parts of fields radiated by finite sources, it is possible to apply the classical image theory for the computation of fields in the presence of a planar generalized SHS boundary. A principle of realization of such a boundary is briefly discussed. If the two vectors defining the boundary can be realized in practice, a device transforming any given polarization to any other polarization in reflection appears feasible.

Relationship between Behavioral Recovery from Unilateral 6-OHDA Lesion of the Substania Nigra and Changes in the Tuberomammillary-Striatal Projection as Measured by HRP-Labelling

The tuberomammillary nucleus (TM) is the only known neuronal cell group in the brain which contains histamine. There is evidence for a reciprocal relationship between the effects of histamine and dopamine on behavior. A unilateral lesion of dopamine cells in the Substantia Nigra (SN) results in asymmetrical behavior, and recovery from this asymmetry was previously found to be associated with asymmetrical changes in the nigro-striatal projection as determined by anatomical tracing technique. In view of the apparent opposing interaction between the TM and the SN, we examined whether the tuberomammillary-striatal projection also shows changes after a unilateral lesion of the SN. Rats had 6-OHDA injected into one substantia nigra and were tested for behavioral asymmetry over a 15 day period. Horseradish peroxidase (HRP) was then deposited in the caudate-putamen (CPU) ipsilateral to the lesion. Controls devoid of a lesion had the tracer deposited in either the right of left CPU. More HRP-labeled cells were found in the anterior part of TM ipsilateral to the lesion in the animals which failed to recover from lesion-induced asymmetry in turning behavior, as compared to normal controls or animals which showed behavioral recovery. The labeled cells in the anterior part of the ipsilateral TM were smaller in animals examined 15 days after the lesions than in the control animals. The results indicate an increase in HRP uptake or transport in the anterior part of the tuberomammillary-striatal projection predominantly ipsilateral to the lesion in animals which failed to recover from lesion induced asymmetry. Previously, we had found an opposite effect in the nigro-striatal projection, namely an increase in HRP uptake or transport only in animals which recovered from their lesion induced asymmetry. The results are discussed in terms of the evidence for a reciprocal relationship between the TM- and SN-striatal systems.

Efficient Analysis of Scattering By Arbitrarily Shaped Thin Obstacles in Rectangular Waveguide

A moment-method based analysis of arbitrarily shaped zero-thickness obstacles in rectangular waveguide is presented. The method is discussed in two well-known formulations, and for both of them an efficient Green's functions representation is introduced. The representation is obtained by extracting suitable terms representing the asymptotic behaviour of the TE and TM part of Green's dyad. Two different sets of basis functions are then compared in terms of accuracy of the numerical results obtained: rooftops and bilinear. It is shown that the higher order set of bilinear basis function leads to spurious results, whereas no such effect appears using rooftops. A very good efficiency of the overall algorithm was observed.