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Summary: Worldwide, conservation agriculture practices involving minimal soil disturbances and retention of crop residue (>30%) have been practised increasingly and recognized to enhance soil health by optimizing key soil attributes. However, little information is available on the short‐term effects of conservation agriculture practices on soil properties under rainfed Vertisols of Central India. Thus, our aim was to study the short‐term effects of contrasting tillage treatments and cropping systems on soil aggregation, aggregate‐associated carbon (C), carbon pools and crop productivity. This study comprised three tillage systems (TS), reduced tillage (RT), no tillage (NT) with retention of crop residue and conventional tillage (CT), together with four cropping systems (CS), namely soya bean (Glycine max L.) + pigeon pea (Cajanus cajan L.) (2:1), soya bean–wheat (Titricum durum L.), maize (Zea mays L.) + pigeon pea (1:1), and maize–chickpea Cicer arietinum L.). The experiment was laid out in a split‐plot design with three replicates. Soil samples were collected at four depths: 0–5, 5–15, 15–30 and 30–45 cm from the experimental field after completion of four crop cycles. Results indicated that at depths 0–5 and 5–15 cm, tillage and cropping system had a significant effect on aggregate mean weight diameter (MWD). The MWDs of 0.97 and 0.94 mm were larger for NT than CT (0.77 and 0.83 mm) at 0–5‐ and 5–15‐cm depths, respectively. Water‐stable aggregates (WSAs) were also larger for NT (70.74%) and RT (70.09%) than CT (59.50%) at 0–5 cm. Tillage practice, cropping system and their interaction had a greater effect (P < 0.05) on the content of aggregate‐associated C for large macroaggregates (LM). There was more aggregate‐associated C for NT and RT at 0–5‐cm depth than for CT. Cropping system also had a significant effect (P < 0.05) on aggregate‐associated C at 0–5‐cm depth. Soil organic C (%) fractions were in the order of non‐labile >very labile >less labile >labile for 0–5‐ and 5–15‐cm depths after four crop cycles. Less labile and non‐labile C fractions contributed >50% of TOC, indicating a more recalcitrant form of carbon present in the soil. Tillage had no significant effect (P > 0.05) on crop yields after four crop cycles. Conservation agriculture can have a positive effect on aggregate stability, aggregate‐associated C and different carbon pools in a Vertisol. Highlights: Does conservation agriculture affect soil aggregation, aggregate stability and carbon pools more than conventional tillage? The SOC concentration increases with aggregate size and provides physical protection and stabilization of carbon (C). Aggregate‐associated C content was significantly affected by tillage practices and cropping system. Less labile and non‐labile C fractions contribute >50% TOC in the rainfed Vertisols of central India. [ABSTRACT FROM AUTHOR]

The organic Rankine cycle solar-thermal power system is a promising concept for the distributed energy market. The present work investigates the automatic generation control of an autonomous hybrid energy system based on organic Rankine cycle solar-thermal technology. Any mismatch between the active power generation and consumption in the hybrid energy system manifests itself as a frequency deviation from the nominal system frequency. To confront the frequency excursion problem, the present work considers automatic generation control, in which the controllers' parameters are optimized by using particle swarm optimization (PSO). The performance of each controller is compared with its genetic algorithm (GA)-optimized counterpart with respect to its ability to capture the frequency variation in the proposed hybrid energy system. The simulation results reveal that the performance of the PSO-optimized controller is better than its GA-optimized counterpart in terms of settling time and overshoot in deviation of frequency. [ABSTRACT FROM AUTHOR]

ABSTRACT Finite element modelling (FEM) is performed on AlN-TiN composites. The structure-property relationships are studied for 5 and 10 vol.% TiN composites in view of thermal and thermo-mechanical properties. Thermal stresses are simulated at various temperatures for the 5 and 10% TiN samples in homogeneous and heterogeneous temperature environments. It is found that compressive stresses are associated with the microstructure and these stresses are largest at the interface of the AlN-TiN phases. In addition, thermal strains are simulated at various temperatures for both the compositions. Thermal conductivity and thermal expansion coefficient are estimated using FEM and compared with other known analytical methods. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize changes in metabolic bone parameters following bariatric surgery. Seventy-three obese adult patients who underwent either gastric banding (GB), Roux-en-Y gastric bypass (RYGB), or biliopancreatic diversion with duodenal switch (BPD/DS) were followed prospectively for 18 months postoperatively. Changes in the calcium-vitamin D axis (25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D (1,25(OH)(2)D), calcium, parathyroid hormone (PTH)), markers of bone formation (osteocalcin, bone-specific alkaline phosphatase) and resorption (urinary N-telopeptide (NTx)), as well as bone mineral density (BMD) were assessed at 3-month intervals during this time period. Bariatric surgery resulted in significant and progressive weight loss over 18 months. With supplementation, 25OHD levels increased 65.3% (P < 0.0001) by 3 months, but leveled off and decreased <30 ng/ml by 18 months. PTH initially decreased 21.4% (P = 0.01) at 3 months, but later approached presurgery levels. 1,25(OH)(2)D increased significantly starting at month 12 (50.3% increase from baseline, P = 0.008), and was positively associated with PTH (r = 0.82, P = 0.0001). When stratified by surgery type, median PTH and 1,25(OH)(2)D levels were higher following combined restrictive and malabsorptive operations (RYGB and BPD/DS) compared to GB. Bone formation/resorption markers were increased by 3 months (P < 0.05) and remained elevated through 18 months. Radial BMD decreased 3.5% by month 18, but this change was not significant (P = 0.23). Our findings show that after transient improvement, preoperative vitamin D insufficiency and secondary hyperparathyroidism persisted following surgery despite supplementation. Postoperative secondary hyperparathyroidism was associated with increased 1,25(OH)(2)D levels and increased bone turnover markers. [ABSTRACT FROM AUTHOR]

Objective To assess vitamin D status and the influences of race, sun exposure and dietary vitamin D intake on vitamin D levels, and to evaluate two vitamin D repletion regimens in extremely obese patients awaiting bariatric surgery. Methods A cross-sectional analysis of dietary vitamin D, sun exposure, PTH [intact (iPTH) and PTH(1-84)] and 25-hydroxyvitamin D (25OHD; differentiated 25OHD2 and 25OHD3) in 56 obese [body mass index (BMI) > 35 kg/m2] men and women (age 20–64 years). In a pilot clinical trial, 27 subjects with 25OHD levels < 62 nmol/l were randomized to receive ergocalciferol or cholecalciferol for 8 weeks. Results Serum 25OHD was low (mean 45 ± 22 nmol/l) and was inversely associated with BMI ( r = −0·36, P < 0·01). Each BMI increase of 1 kg/m2 was associated with a 1·3 nmol/l decrease in 25OHD ( P < 0·01). BMI, sun exposure, African American race and PTH predicted 40% of the variance in 25OHD ( P < 0·0001). Serum 25OHD significantly increased at 4 and 8 weeks in both treatment groups ( P < 0·001), whereas PTH(1-84) declined significantly in subjects treated with cholecalciferol ( P < 0·007) and tended to decrease following ergocalciferol ( P < 0·09). Conclusions In severely obese individuals, those who are African American, have higher BMI and limited sunlight exposure are at greatest risk for vitamin D insufficiency. These demographic factors can help to identify at-risk patients who require vitamin D repletion prior to bariatric surgery. Commonly prescribed doses of ergocalciferol and cholecalciferol are effective in raising 25OHD. Further investigation is needed to evaluate whether these regimens have differential effects on PTH, and to determine the optimal regimen for vitamin D repletion in the extremely obese patient. [ABSTRACT FROM AUTHOR]

INTRODUCTION Routine diagnostic techniques are not sufficient to confidently differentiate diseases of the axial skeleton. Purpose of study was to determine whether CT perfusion (CTP) can differentiate inflammatory diseases like tuberculosis from neoplastic diseases of spine. METHODS Fifty-one patients with vertebrdraft%freshal body lesions associated with paraspinal mass underwent CT guided bone biopsy and histopathological evaluation. CTP was done before doing bone biopsy. Perfusion parameters like blood volume (BV), blood flow (BF), and time to peak (TTP) were calculated. Values are correlated with histopathological report of bone biopsy. Statistical analysis was done using Mann-Whitney test. P value < .05 was considered significant. RESULTS Of 51, 32 had infective osteomyelitis and 19 neoplastic disease (9 metastasis, 5 plasmacytoma, 4 lymphoma and 1 chordoma. Mean rBF was [inflammatory lesions, 1.79 and neoplastic lesions, 9.42 ( P < .000)]. Mean rBV was [inflammatory disease, 1.63 and neoplastic lesions, 9.37 ( P < .000)]. CONCLUSION CTP technique has potential for differentiating inflammatory from neoplastic lesions affecting spine associated with paraspinal mass noninvasively. [ABSTRACT FROM AUTHOR]

Peptides have been instrumental in the development of solid-state nuclear magnetic resonance (NMR) spectroscopy, and their roles in the development of solid-state NMR of aligned samples is reviewed. In particular, the roles of synthetic peptides in the development of triple-resonance methods are described. Recent developments of pulse sequences and NMR probes for triple-resonance NMR of aligned samples are presented. [ABSTRACT FROM AUTHOR]

Barley varieties were screened for their efficient drought enduring ability and associated characters which may be useful in breeding programmes. The characters studied were: relative water content, content of proline, chlorophyll stability index (CSI), and percentage grain loss per plant due to water stress subjected to 10 days from jointing to boot stage. Proline and chlorophyll stability index were greatly associated with drought response (r = +0.54; -0.49), flag leaf area (r = +0.69; -0.51) and, to a certain extent, with leaf number (r = -0.35 and +0.34). Among the studied 19 varieties of barley, only three (DL 192, DL 36, DL 3) showed high enduring ability, of these the former two fall in the early, and the last one in the late flowering group. Morphological architecture of DL 192 had gathering type tiller (narrow tiller angle), wider and floppy leaves and it also bears physiological characters (high proline and high relative water content, and low value of chlorophyll stability index) necessary for drought resistance. DL 3 and DL 36 had dispersing type tiller (wider tiller angle) and erect leaf with good leaf area/plant, but unit leaf area was low in DL 3 (relates with shading behaviour reducing water loss). Other relations of drought resistance are briefly discussed in the text. An appraisal of the various traits revealed that high proline content, and low CSI (biochemical characters), earliness, larger flag leaf area and fewer leaves per plant (morphological characters) were directly correlated with productivity of the cultivars under drought conditions. These characters could be used as a guideline for breeding drought resistant cultivars of barley. [ABSTRACT FROM AUTHOR]

Five plum cultivars were investigated for polyphenoloxidase. Stanley cultivar, which showed highest PPO activity, was selected for characterization of this enzyme. The activity of crude enzyme was 3.5 times greater in the flesh than in the skin of the fruit. The enzyme showed a Km of 20 mM of catechol and Vmax of 5.41 x 10−1 O.D./min at pH 6.0. Its pH and temperature optima were 6.0 and 20°C respectively. The enzyme lost activity below pH 4.5, but was stable even at 70°C. Among substrates, 4-methylcatechol was oxidized more rapidly, although catechol, dopamine, pyrogallol and caffeic acid were also good substrates. The enzyme was strongly inhibited by sodium metabisulfite Na2S2O5), L-cysteine and ascorbic acid. [ABSTRACT FROM AUTHOR]

Purpose: To determine the number of torque/reverse torque cycles attachment screws can withstand before fracture, and to record the magnitude of reverse torque values for each of the 10 cycles of screw tightening and loosening., Materials and Methods: The testing assemblies consisted of 30 temporary cylinder/multiunit abutment/internal connection implants (10 each from Dentsply Sirona Astra, Biohorizons, and Zimmer Biomet Dental). The assemblies were inserted into resin blocks, and temporary cylinders were connected to the multiunit abutments with new attachment screws and torqued to the recommended preload (15 Ncm Dentsply Sirona Astra; 15 Ncm Biohorizons; 10 Ncm Zimmer Biomet Dental) using a digital torque gauge instrument (Model 3, MARK-10 Corporation, New York, USA) at room temperature without lubrication. After 24 h, the attachment screws were reverse torqued with the same instrument and the values were recorded. The torque/reverse torque cycles were repeated every 24 h for 10 days. Data were analyzed using mixed model analysis. A second test included torquing the used screws (30) until fracture or stripping occurred. The reverse torque values were recorded and compared with new screws that were torqued until fracture or stripping. A sample of used and new attachment screws from each assembly were viewed under both laser microscope (LEXT OLS4000, 3D Measuring Laser Microscope, Olympus) and scanning electron microscope (JEOL-JSM6510, Tokyo, Japan). Data were analyzed using t-test., Results: Following 10 cycles of torquing and reverse torquing, the reverse torque values measured on day 10 were lesser compared with the reverse torque value measured on day 1 for 29/30 attachment screws (96.6%). According to the t-test used for the second test, the p-values among all three groups were ≥0.9 which were not statistically significant., Conclusion: The results of this study indicated that after 10 cycles of torquing and reverse torquing attachment screws, the reverse torque values decreased. There were no statistical differences between the magnitude of torque necessary to fracture new and used attachment screws., (© 2024 by the American College of Prosthodontists.)

Purpose: The purpose of this in vitro study was to analyze the shear bond strength of composite resin to a commercially available high-performance polymer material for fixed, screw-retained full arch restorations., Material and Methods: A total of 135 computer-aided design and computer-aided manufacturing, high-performance polymer (HPP) blocks were cut and obtained from discs (Trilor 95, Harvest Dental, Brea, CA). The samples were 10 mm × 10 mm × 10 mm. The specimen surfaces were grouped as untreated (Group A), 50 μm Al2O3 (Group B), 110 μm Al2O3 (Group C), Rocatec (3 M, St. Paul, MN) activated with silica-modified alumina oxide treatment (Group D); and trimmed coarsely with a carbide bur (Group E). Group A samples were used as controls. After surface treatments, the specimens were gently cleansed with oil-free steam and alcohol wipes. Surface conditioning was performed on all physically treated samples.  The manufacturer's recommendations were followed for bonding composite resin to the samples with light-cured Visio.link (Bredent, Chesterfield, UK). Cylinders were veneered with composite resins (diameter 5 mm, height 4 mm) and polymerized on the specimen surfaces through plastic tubes. Twenty-seven specimens were used for each testing group and aging tests were performed. The experimental samples were thermocycled.  Shear bond strength and scanning electron microscopic tests were performed. Means and standard deviations were calculated.  Statistical analysis was performed with post-hoc Tukey tests., Results: Statistical analysis revealed that there was a significant difference between the groups (p<0.001). The highest shear bond strengths were achieved for the specimens bonded with Visio.link without physical surface treatments (270.47 MPa). The lowest bond strengths were found for specimen surfaces abraded with 110 μm Al2O3 (117.03 Mpa) CONCLUSIONS: The results of this laboratory study indicated that the specimens used with Visio.link as provided by the manufacturer had the highest shear bond strengths between the composite resin and high-performance polymer test specimens. Modifications of the high-performance polymer surfaces with carbide burs did not change bonding strengths with the composite materials., (© 2023 by the American College of Prosthodontists.)

Complications of the bronchial anastomosis in lung transplantation, once the Achilles heel of the procedure, have become quite rare. The surgical technique is well established and safe. Risks contributing to anastomotic complications are primarily related to patients pre-existing conditions. The key factor is good blood flow to the bronchial stump. Postoperative infection can also contribute to the breakdown of the anastomosis. This may be the reason why different immunosuppressive regimes lead to differences in the incidence of bronchial dehiscence., (© 2022 Wiley Periodicals LLC.)

The causal role of somatic mutation and its interrelationship with gene expression profile during tumor development has already been observed, which plays a major role to decide the cancer grades and overall survival. Accurate and robust prediction of tumor grades and patients' overall survival are important for prognosis, risk factors identification and betterment of the treatment strategy, especially for highly lethal tumors, like gliomas. Here, with the help of more accurate and widely used machine learning-based approaches, we propose an integrative computational pipeline that incorporates somatic mutations and gene expression profile for survival and grade prediction of glioma patients and simultaneously relates it to the drugs to be administered. This study gives us a clear understanding that the same drug is not effective for the treatment of same grade of cancer if the gene mutations are different. The alteration in a specific gene plays a very important role in tumor progression and should also be considered for the selection of appropriate drugs. This proposed framework includes all the necessary factors required for enhancement of therapeutic designs and could be useful for clinicians in determining an accurate and personalized treatment strategy for individual patients suffering from different life threatening diseases., (© 2020 John Wiley & Sons A/S.)

Purpose: To identify associations between early implant failure and prosthodontic characteristics that could be used to guide subsequent continuous quality improvement efforts of patient care., Materials and Methods: An implant-level analysis was performed in which data were abstracted from a prospective clinical database of all adult patients treated with implants and followed up from January 2000 through December 2014 at the Department of Dental Specialties at Mayo Clinic in Rochester, Minnesota. These data were used to determine time to implant failure. Associations between prosthodontic characteristics and early implant failure were evaluated with Cox proportional hazards regression models and summarized with hazard ratios (HRs) and 95% confidence intervals (CIs)., Results: Among 8762 implants in 2787 patients, 395 (4.5%) failed within the first year of placement at a mean (SD) of 127 (97) days (range, 2-364 days). Univariable analysis showed no associations between early implant failure and use of a cover screw, prosthesis, or definitive or provisional prosthesis at implant placement. Three of 25 single crowns failed, and use of a single crown was significantly associated with early implant failure (HR, 3.94; 95% CI, 1.08-14.35; P = 0.04). This study identified no significant associations between prosthodontic characteristics identified after implant placement and early implant failure., Conclusions: Use of a prosthesis at implant placement, use of a definitive or provisional prosthesis, and early mechanical complications were not associated with increased risk of early implant failure. Quality improvement efforts should focus on aspects of decision making that aim to decrease surgical complications., (© 2018 by the American College of Prosthodontists.)

Background: The fasting-state serum bile acid profile in nonalcoholic fatty liver disease (NAFLD) has been reported to differ when nonalcoholic steatohepatitis is compared to nonalcoholic fatty liver. However, there are few data comparing changes in NAFLD vs non-NAFLD, or whether the bile acid profile differs according to the degree of fibrosis., Aim: To examine the serum bile acid profile across the entire spectrum of NAFLD., Methods: We performed a cross-sectional analysis of two complementary cohorts: a Twin and Family cohort of 156 participants, and a biopsy-proven-NAFLD cohort of 156 participants with fasting bile acid profiling using liquid chromatography/mass spectrometry., Results: In the Twin and Family cohort (mean age 46.3 years and body mass index (BMI) 26.6 kg/m 2 ), 36 (23%) participants had NAFLD (magnetic resonance imaging proton density fat fraction ≥ 5%). Higher chenodeoxycholyl conjugates (9.0% vs 6.5%, P = 0.019) and lower glycohyocholate (1.2% vs 3.6%, P < 0.001) were observed in NAFLD compared to non-NAFLD-controls. In the biopsy-proven-NAFLD cohort (mean age 49.8 years, BMI 32.0 kg/m 2 ), no differences in total bile acid were seen between nonalcoholic fatty liver vs nonalcoholic steatohepatitis. The total unconjugated bile acid significantly decreased across nonalcoholic steatohepatitis categories (P = 0.044). The distribution of stage of fibrosis was F0: 42.3%, F1: 32.7%, F2: 10.3%, F3: 8.3% and F4: 6.4%. The total serum bile acid increased with increase in fibrosis stage (P < 0.001). The primary conjugated bile acid proportion increased (P < 0.001) whereas unconjugated bile acid (P = 0.006), unconjugated cholyl (P < 0.001) and chenodeoxycholyl conjugates (P < 0.002) significantly decreased with increase in liver fibrosis stage., Conclusions: Fasting-state serum bile acid profile alterations are seen across the entire spectrum of NAFLD. The total serum bile acids did not differ significantly between NAFLD vs non-NAFLD and nonalcoholic fatty liver vs nonalcoholic steatohepatitis, but were significantly perturbed progressively as liver fibrosis increases., (© 2018 John Wiley & Sons Ltd.)

Molecular organic single crystals of bis(L-asparaginium hydrogensquarate) monohydrate [BASQ; (C 8 H 10 N 2 O 7 ) 2 ·H 2 O] have been grown by solution technique. Crystallographic information was investigated by single-crystal X-ray diffraction (SCXRD) analysis. Hirshfeld surface and fingerprint plot studies were performed to understand the intermolecular interactions of the BASQ crystal in graphical representation. Functional group identification was studied with FT-IR (Fourier transform-IR) spectroscopy. The positions of proton and carbon atoms in the BASQ compound were analyzed using NMR spectroscopy. High transparency and a wide band gap of 3.49 eV were observed in the linear optical study by UV-vis-NIR spectroscopy. Intense and broad photoluminescence emissions at room temperature were observed in blue and blue-green regions. The frontier molecular orbitals of the BASQ molecule were obtained by the DFT/B3LYP method employing 6-311G** as the basis set. The dielectric study was carried out with temperature at various frequency ranges. The piezoelectric charge coefficient (d 33 ) value of BASQ crystal was found to be 2 pC/N, which leads to its application in energy harvesting, mechanical sensors and actuators applications. In the non-linear optical study, the BASQ crystal showed promising SHG conversion efficiency. Mechanical properties of the BASQ crystal were studied experimentally by Vicker's microhardness technique, which revealed that the grown crystal belonged to the softer category. BASQ crystal void estimation reveals the mechanical strength and porosity of the material.

L-Histidinium dihydrogen arsenate orthoarsenic acid (LHAS) crystals were grown by the slow evaporation method. Single-crystal X-ray diffraction confirms monoclinic structure. The growth rates of various planes of LHAS crystals were estimated by morphological study. Hirshfeld surface and fingerprint plots were analyzed to investigate the intermolecular interactions at 0.002 a.u. present in the crystal structure. The functional groups and phase behavior of the compound are studied by FTIR spectroscopy and differential scanning calorimetry (DSC). A ferroelectric to paraelectric phase transition at 307 K was observed in dielectric studies. The piezoelectric charge coefficients of the grown crystal were found to be 2 pC/N. The values of coercive field (Ec), remnant polarization (Pr) and spontaneous polarization (Ps) in the hysteresis loop are found to be 5.236 kV cm(-1), 0.654 µC cm(-2) and 2.841 µC cm(-2), respectively. Piezoelectricity and ferroelectricity are reported for the first time in LHAS crystals. The mechanical strength was confirmed from microhardness study and void volume. Due to the low value of the dielectric constant, and good piezoelectric and ferroelectric properties, LHAS crystals can be used in microelectronics, sensors and advanced electronic devices.

Impulse control disorders (ICDs) and apathy are recognized as two important neuropsychiatric syndromes associated with Parkinson's disease (PD), but as yet we understand very little about the cognitive mechanisms underlying them. Here, we review emerging findings, from both human and animal studies, that suggest that impulsivity and apathy are opposite extremes of a dopamine-dependent spectrum of motivated decision making. We first argue that there is strong support for a hypodopaminergic state in PD patients with apathy, as well as for an association between dopamine therapy and development of ICDs. However, there is little evidence for a clear dose-response relationship, and great heterogeneity of findings. We argue that dopaminergic state on its own is an insufficient explanation, and suggest instead that there is now substantial evidence that both apathy and impulsivity are in fact multi-dimensional syndromes, with separate, dissociable mechanisms underlying their 'surface' manifestations. Some of these mechanisms might be dopamine-dependent. According to this view, individuals diagnosed as impulsive or apathetic may have very different mechanisms underlying their clinical states. We propose that impulsivity and apathy can arise from dissociable deficits in option generation, option selection, action initiation or inhibition and learning. Review of the behavioural and neurobiological evidence leads us to a new conceptual framework that might help understand the variety of functional deficits seen in PD., (© 2013 The British Psychological Society.)

The mitral valve aneurysm is a rare disease that is usually induced by infective endocarditis. While the mechanism of the development of this lesion is unclear, complications such as perforation can occur and lead to significant mitral regurgitation. We describe a patient presented with ruptured aneurysm of anterior mitral leaflet resulting in acute severe mitral regurgitation that was confirmed by transthoracic and transesophageal echocardiography. Early detection and prompt intervention are important to prevent the complications of valvular aneurysms, which include rupture, embolism, and endocarditis. This report emphasizes the role of echocardiography in evaluating the mitral valve aneurysms and its complications., (© 2010, Wiley Periodicals, Inc.)

In abstinent opiate addicts, relapse can be triggered by exposure to environmental cues associated with drug use; thus, the disruption of these learned associations may be an effective approach for reducing relapse. Interestingly, glutamatergic systems are thought to be involved in opiate-induced behavioral plasticity. In this study, changes in expression and phosphorylation levels of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor subunits (GluR1, GluR2) in the hippocampus were investigated in rats showing a conditioned response (CR) to an opiate-paired environment as well as in animals in which this conditioned behavior was extinguished. Additionally, another set of animals went through a drug-unpaired paradigm (without conditioning) in order to examine the effects of the pharmacology of the drug itself. Subcellular fractionation techniques were used to analyse the local distribution of AMPA glutamate subunits within the synapse, especially at the postsynaptic density (PSD). Results showed that morphine-dependent CRs did not alter expression or redistribution of GluR1 or GluR2; however, the unpaired administration of morphine resulted in an increase in the phosphorylation of the GluR1 subunit at extrasynaptic sites. Interestingly, the extinction of the CR significantly increased phosphorylation of the GluR1 subunit at the PSD. Therefore we propose that, within the synapse, the phosphorylation of the GluR1 subunit at the PSD may be a key mechanism in the extinction of opiate-associated CRs.

The crystal structure of d(ACCCT), solved by molecular replacement, shows a four-stranded i-motif conformation, where two parallel duplexes intercalate with one another in opposite orientations. Each duplex is stabilized by hemi-protonated C-C+ base pairing between parallel strands, and a string of water molecules bridge the cytosine N4 atoms to phosphate O atoms. This structure of d(ACCCT) shows examples of reversed Hoogsteen and Watson-Crick base pairing in both intermolecular and intramolecular manners to stabilize the tetraplex. Noticeably, the four-stranded complex is further stabilized at one end by a three-base hydrogen-bonding network, in which two adenines and a thymine form four hydrogen bonds via a reverse Hoogsteen and an asymmetric adenine-adenine base pairing. The structure of d(ACCCT) shows a similar local structure to that found in the d(TAA) part of the crystal structure of d(TAACCC) and provides further structural evidence that these base arrangements are essential for stabilizing these novel DNA super-secondary structures.