Fentanyl Research Articles

Synthesis of a Calcium Silicate Cement Containing a Calcinated Strontium Silicate Phase.

The positive effects of strontium on dental and skeletal remineralization have been confirmed in the literature. This study aimed to assess the properties of a calcium silicate cement (CSC) containing a sintered strontium silicate phase. The calcium silicate and strontium silicate phases were synthesized by the sol-gel technique. Strontium silicate powder in 0 (CSC), 10 (CSC/10Sr), 20 (CSC/20Sr), and 30 (CSC/30Sr) weight percentages was mixed with calcium silicate powder. Calcium chloride was used in the liquid phase. X-ray diffraction (XRD) of specimens was conducted before and after hydration. The setting time and compressive strength were assessed at 1 and 7 days after setting. The set discs of the aforementioned groups were immersed in the simulated body fluid (SBF) for 1 and 7 days. The ion release profile was evaluated by inductively coupled plasma-optical emission spectrometry (ICP-OES). Biomineralization on the specimen surface was evaluated by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Data were analyzed by the Kolmogorov-Smirnov test, one-way and mixed ANOVA, Levene's test, and LSD post hoc test (P < 0.05). Except for an increasement in the peak intensity of hydrated specimens, XRD revealed no other difference in the crystalline phases of hydrated and nonhydrated specimens. The compressive strength was not significantly different at 1 and 7 days in any group (P > 0.05). The setting time significantly decreased by an increase in percentage of strontium (P < 0.05). Release of Ca and Si ions significantly decreased by an increase in percentage of strontium (P < 0.05). SEM/EDS showed the formation of calcium phosphate deposits at 1 and 7 days. Incorporation of 10-30 wt% sintered strontium silicate phase as premixed in CSC can significantly decrease the setting time without compromising the compressive strength or biomineralization process of the cement.

Effects of fentanyl and the adulterant levamisole on the rewarding and locomotor effects of methamphetamine in rats

BackgroundPeople who use psychostimulant substances can be exposed to unknown adulterants, such as the synthetic opioid fentanyl (FEN) and the anthelmintic cholinergic agent levamisole (LEV). This work explores the rewarding and locomotor effects of methamphetamine (METH) in combination with FEN or LEV. MethodsWe used adult male Wistar rats in the conditioned-place preference (CPP) paradigm (conditioning, extinction, and reinstatement phases) and in the open field test to study effective doses of METH, FEN, or LEV, or ineffective doses of METH+FEN or METH+LEV in combination. ResultsMETH and LEV, at 1mg/kg METH each, and 30µg/kg FEN produced CPP. Extinction to METH- or LEV-induced CPP occurred after eight saline injections, but it took 8–26 sessions to extinguish FEN-induced CPP. A challenge dose of 0.5mg/kg METH reinstated CPP. The same occurred with 15µg/kg FEN but not with 0.5 or 1mg/kg LEV. Training animals with ineffective doses of METH (0.01mg/kg) combined with either FEN (0.3µg/kg) or LEV (0.01mg/kg) produced CPP. Sub-effective doses of METH or FEN alone did not induce reinstatement after extinction. However, animals challenged with LEV, METH+FEN, or METH+LEV mixtures did it. Combining FEN (3µg/kg) with 0.1mg/kg METH increased locomotor activity. ConclusionIneffective FEN and LEV doses mixed with METH produce effects larger than would be expected based on the effects of either drug alone. This outcome suggests a supra-additive interaction, which could increase the risk of developing a METH use disorder.

Rare-earth elements improving the corrosion resistance of YSZ/CMAS heterojunction with stacking faults: First-principles calculation

Stacking faults cannot be fully eliminated from yttrium partially stabilized zirconia (YSZ) ceramic coatings. However, their influence on the corrosion resistance of YSZ ceramics has remained unclear up till now. In this study, the impact of stacking faults on the corrosion resistance of YSZ with or without Nd dopant in CaO, MgO, Al2O3 and SiO2 (CMAS) melts was characterized via first-principles calculations. As expected, the stacking faults decrease the corrosion resistance of YSZ, especially at the saddle point along the slip way within the YSZ(111)V surface. Moreover, the Nd dopant can increase the corrosion resistance of YSZ due to its enhanced structural stability and enlarged wetting angle. Thoroughly analyzing the growth of stacking faults, it is found that the most pronounced effect of Nd dopant on the corrosion resistance of YSZ occurs only at the initial and final stages, whereas being less noticed at the saddle point of the slip way of faults. In addition, compared to the earlier studies, it is established that the largest penetration depth within the ceramic is achieved by Si ions, which broadens the knowledge about the main corrosion factors, as well as reveals the weakest O-Ca bond and the largest diffusion constants of Ca and Mg ions. Thus, the findings of this work open up new prospects for understanding the corrosion mechanism of YSZ TBCs in CMAS melt.

Augmented physical, mechanical, and cellular responsiveness of gelatin-aldehyde modified xanthan hydrogel through incorporation of silicon nanoparticles for bone tissue engineering

Bioactive scaffolds fabricated from a combination of organic and inorganic biomaterials are a promising approach for addressing defects in bone tissue engineering. In the present study, a self-crosslinked nanocomposite hydrogel, composed of gelatin/aldehyde-modified xanthan (Gel-AXG) is successfully developed by varying concentrations of porous silicon nanoparticles (PSiNPs). The effect of PSiNPs incorporation on physical, mechanical, and biological performance of the nanocomposite hydrogel is evaluated. Morphological analysis reveals formation of highly porous 3D microstructures with interconnected pores in all nanocomposite hydrogels. Increased content of PSiNPs results in a lower swelling ratio, reduced porosity and pore size, which in turn impeded media penetration and slowed down the degradation process. In addition, remarkable enhancements in dynamic mechanical properties are observed in Gel-AXG-8%Si (compressive strength: 0.6223 MPa at 90 % strain and compressive modulus: 0.054 MPa), along with improved biomineralization ability via hydroxyapatite formation after immersion in simulated body fluid (SBF). This optimized nanocomposite hydrogel provides a sustained release of Si ions at safe dose levels. Furthermore, in-vitro cytocompatibility studies using MG-63 cells exhibited remarkable performance in terms of cell attachment, proliferation, and ALP activity for Gel-AXG-8%Si. These findings suggest that the prepared nanocomposite hydrogel holds promising potential as a scaffold for bone tissue engineering.

Bi6Te2-xRxO13 (R=Ti, Si, Ce) Systems: A Investigation for Fuel Cell Applications

In recent years, the increase of economic and environmental problems related to energy generation has increased researches at renewable energy sources. Among others, the fuel cells excel as promising alternative technology of electricity generation and materials science is an ally in the search for better and more efficient materials for this application. In particular, solid-state ionic conductors represent functional materials with promising advantages for fuel cells, as is the case of Bi2O3-based oxygen ion conductors, however, they need to have its cubic phase stabilized at room temperature. This paper presents a study of the Bi6Te2-xRxO13 (R = Ti, Si and Ce) systems for such an application. Solid state reaction was used to materials synthesis. The 3Bi2O3:2TeO2 system present two phases, an orthorhombic one (Bi6Te2O15) stable at room temperature and another high temperature cubic (Bi6Te2O13). Experiments of substitution of Te ions by Ti, Si and Ce ions using the Bi6Te2- xRxO13 matrix were done intending to stabilize the cubic phase at room temperature and the results are presented as well as discussed here.

Removal of NO with Fe(II)NTA solution catalyzed by the carbon treated with ethylenediamine

Removal of NO with Fe(II)NTA solution catalyzed by the carbon treated with ethylenediamine

Evaluation of pharmacological alternatives to reduce the pain and discomfort produced by electroejaculation in rams

AbstractElectroejaculation (EE) represents the main technique for semen collection from domestic and wild animals independently of libido. However, the technique is associated with intense involuntary muscle contractions, vocalization, ataxia and lying down, caused by the electric stimulation of the nerves in the caudal epigastric region. These clinical manifestations represent important indicators of discomfort. In this context, the objective of this study was to evaluate two protocols of local anaesthetic blockade and two anatomical access for pharmacological desensitization of the caudal epigastric innervation as alternatives to promote comfort and reduce stress associated with EE in rams. For the study, four clinically healthy Dorper rams were selected. All animals were subjected to a design consisting of five semen collection treatments (n = 3 collections per treatment): T1—control, conventional EE without local anaesthetic blockade; T2, EE with ventral blockade (VB) of epigastric innervation using lidocaine hydrochloride 2%; T3, EE with VB of epigastric innervation using a combination of lidocaine hydrochloride 2% and fentanyl citrate; T4, EE with blockade of epigastric innervation through the perineal access using lidocaine hydrochloride 2%; T5, EE with blockade of epigastric innervation through the perineal access using a combination of lidocaine hydrochloride and fentanyl citrate. Seminal samples resulting from EE were subjectively evaluated for sperm motility and concentration, vigour and volume. Additionally, blood serum samples were collected for quantification of cortisol and creatine kinase (CK) enzyme. Assessments of stress and discomfort were conducted by measuring blood pressure, heart rate (HR) and respiratory rate (RR), as well as observing involuntary muscle contractions, ataxia and animal vocalization. No variations in blood pressure, sperm motility, vigour, CK, and cortisol were observed among the treatments. Individual variations were observed for the occurrence of vocalization (p = .0066), but there were no differences between the groups. Anaesthetic blockades conducted using the combination of lidocaine and fentanyl resulted in a lower incidence of ataxia during EE (p &lt; .0001). It is concluded that the combination of fentanyl citrate and lidocaine hydrochloride results in less discomfort for animals undergoing EE, regardless of the anatomical access used for local anaesthetic blockades.

A bioactive multifunctional dressing with simultaneous visible monitoring of pH values and H2O2 concentrations for promoting diabetic wound healing.

Wound healing in diabetes is a complex physiological process with risks of ulceration and amputation. Real-time monitoring and treatment of diabetic wounds is an effective prevention of further deterioration. Herein, a multifunctional dressing is developed by encapsulating europium-containing bioactive glass (EuBG) and MoO3-x in a biocompatible sodium alginate (SA) dressing (MoO3-x-EuBG-SA), aiming to simultaneously monitor the wound pH value and hydrogen peroxide (H2O2) concentration, establish an anti-inflammatory microenvironment, and promote wound healing. The pH-responsive fluorescence quenching effect of EuBG contributes to visible monitoring of pH values, and MoO3-x enables high responsiveness and accurate colorimetric indication of H2O2 variability to understand the dynamic wound status. Then, these fluorescent and colorimetric changes can be captured using a smartphone and transformed into signals for wound pH values and H2O2 concentrations, enabling rapid and convenient real-time assessment of wound dynamics. Furthermore, the MoO3-x-EuBG-SA dressing can reduce inflammation and promote the proliferation, differentiation, and migration of fibroblasts and endothelial cells in vitro with the help of the released bioactive Si, Ca, and Mo ions. Notably, the MoO3-x-EuBG-SA dressing exhibits excellent abilities to monitor a wound microenvironment and immune regulation and promote diabetic wound healing in vivo. Overall, the multifunctional dressing has great potential for managing diabetic wounds and promoting wound healing.

Porosity generation via spatially uncoupled dissolution precipitation during plagioclase replacement in quartz undersaturated fluids

The replacement of feldspars is commonly characterized by pseudomorphism and reaction-induced pore generation. However, the effects of compositions of feldspars and fluids on porosity generation during alteration are still poorly understood. In this study, we conducted a series of hydrothermal experiments on plagioclase replacement by 2 M KCl or NaCl aqueous solutions at 600 °C and 150 MPa for 1–8 days, using plagioclase with different compositions (anorthite, An96Ab4; labradorite, An66Ab33Or1; albite, An1Ab99) with or without quartz. Albite replacement by K-feldspar was not affected by the presence of quartz, whereas anorthite was unaltered in the quartz-absent fluid. The replacement of labradorite by KCl(aq) showed different results: in the presence of quartz, labradorite was altered by K-feldspar, whereas in the absence of quartz, alteration proceeded significantly with the generation of large pores hosted by secondary anorthite coupled with euhedral K-feldspar overgrowth. Such textural relationship and oxygen isotope-labeled experiments reveal that silica-deficient fluid enhances the uncoupled dissolution reprecipitation process. The Si and Al ions in the reacted aqueous solution diffused outside the labradorite grains and encountered K+-rich solutions to grow K-feldspar. The experiments with polycrystalline rocks composed of amphibole + labradorite using 2 M KCl aqueous solution indicated the replacement of labradorite grains by anorthite and K-feldspar overgrowth, as found in single-crystal experiments. Our results indicate that the silica concentration in the fluids has different influences on the saturation indices of albite, anorthite, and K-feldspars in saline fluids, which significantly affect the replacement textures and porosity generation in crustal rocks.

Deployed Combat Use of Methoxyflurane for Analgesia.

The U.S. Military needs fast-acting, non-opioid solutions for battlefield pain. The U.S. Military recently used morphine auto-injectors, which are now unavailable. Off-label ketamine and oral transmucosal fentanyl citrate use introduces challenges and is therefore uncommon among conventional forces. Sublingual suftentanil is the only recent pain medication acquired to fill this gap. Conversely, methoxyflurane delivered by a handheld inhaler is promising, fast-acting, and available to some partner forces. We describe methoxyflurane use reported in the Department of Defense Trauma Registry (DODTR). We requested all available DODTR encounters from 2007 to 2023 with a documented intervention or assessment within the first 72 hours of care. We analyzed casualties who received methoxyflurane in the prehospital setting using descriptive statistics. There were 22 encounters with documented methoxyflurane administration. The median patient age was 23 (range 21-31) years. All were men. The largest proportion was partner force (50%), followed by U.S. Military (27%). Most (64%) sustained battle injuries. Explosives were the most common mechanism of injury (46%), followed by firearms (23%). The median injury severity score was 5 (range 1-17). The most frequent injuries were serious injuries to the extremities (27%), and 23% of patients (5) received a tourniquet. One-half of the casualties received concomitant pain medications. Only three casualties had multiple pain scores measured, with a median pain score change of -3 on a scale of 10. Methoxyflurane use in deployed combat shows both feasibility and usability for analgesia.

Enhancement of Selectivity for Chemical Mechanical Polishing by Ultra-High-Dose C and Si Ion Implantation

Enhancement of Selectivity for Chemical Mechanical Polishing by Ultra-High-Dose C and Si Ion Implantation

Performance Evaluation of Multi-Drug Rapid Test for Rapid Detection of Multiple Drugs and Drug Metabolites in Human Blood Samples

Objective: The Multi-Drug Rapid Test Cassette, developed by Hangzhou AllTest Biotech Co., Ltd, is a rapid chromatographic immunoassay designed for the qualitative detection of multiple drugs and drug metabolites in human whole blood, serum, or plasma. It aims to simultaneously detect various abused substances, including Amphetamine (AMP), Barbiturates (BAR), Benzodiazepines (BZO), Buprenorphine (BUP), Cocaine (COC), Cannabis (THC), Methadone (MTD), Methamphetamine (MET), 3,4-Methylenedioxymethamphetamine (MDMA), Morphine (MOP/OPI), Propoxyphene (PPX), Tricyclic antidepressants (TCA), Oxycodone (OXY), 2-Ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), Cotinine (COT), Tramadol (TML), Fentanyl (FYL), 3,4-Methylenedioxy pyrovalerone (MDPV), Synthetic cannabinoids(K2), Phencyclidine(PCP), Ketamine(KET), Lysergic acid diethylamide(LSD), 3,4-Methylenedioxyamphetamine(MDA), Acetaminophen(ACE), Ketamine(CAT), 6-Monoacetylmorphine (6-MAM), Zolpidem (ZOL), AB-PINACA (ABP/K3). Therefore, the present research was done to evaluate the diagnostic performance of this test. Material and Method: In this study, the accuracy, precision, and sensitivity of the drug testing methods were assessed. Approximately 100 specimens of each drug, obtained from previous drug screening tests, were tested. The results were compared to confirmatory analysis using GC/MS, and the accuracy of the testing was determined based on the comparative classification results. The evaluation of precision included measuring the consistency of measurements within a single run, between different runs, and among different operators, using the AllTest multi-drug detection tool across three different hospitals and three different batches. To evaluate the sensitivity of the detection method, various concentrations of drugs were added to a pool of whole blood, serum, or plasma without any drugs. The positive and negative results obtained from the testing were analyzed to assess the method’s ability to detect drugs at different concentrations. Results: In this study, we evaluated the performance of the Multi-Drug Rapid Test Cassette developed by Hangzhou AllTest Biotech Co., Ltd. The results demonstrated excellent performance of the test in terms of accuracy, sensitivity, and precision. Conclusion: The Multi-Drug Rapid Test Cassette developed by Hangzhou AllTest Biotech Co., Ltd exhibited reliable detection of multiple drugs and drug metabolites, providing trustworthy results for drug abuse screening. These findings have significant implications for drug control and monitoring, as well as supporting the broad application of this test in clinical and legal settings.

Coordination Structure of Si(II) Ions in Binary Melts (LiF-KF, LiF-NaF, and NaF-KF) and Ternary Melt (LiF-NaF-KF).

The formation of Si(II) by the comproportionation reaction between electrodeposited silicon and Si(IV) ions [Si(IV) + Si0 ⇄ 2Si(II)] in fluoride melts has been discussed in many previous reports on the electrochemical processing of silicon. In this study, the coordination structure of Si(II) ions in LiF-KF, LiF-NaF, NaF-KF, and LiF-NaF-KF melts was investigated by high-temperature Raman spectroscopy and quantum chemical calculation based on density functional theory. The formation of Si(II) ions was induced by mixing metallic silicon powder as the source of Si0, with the melts containing hexafluoro silicate or silicon dioxide as the source of Si(IV) ions. The simulated vibrational modes of the Si(II) species and the experimental Raman bands showed good agreement. It was found that both Si(II) and Si(IV) species were detected in either fluoride melt, demonstrating that the proposed comproportionation reaction between Si0 and Si(IV) occurred. In addition, the interaction between Si(II) and F-, O2-, Li+, Na+, and K+ ions significantly changed depending on the composition of fluoride melts. The coordination structure of the Si(II) ions reported in this study will provide clues for controlling the electrodeposition process of silicon in fluoride melts.

Acidithiobacillus species drive the formation of ferric-silica cemented microstructure: Insights into early hardpan development for mine site rehabilitation

Hardpan-based profiles naturally formed under semi-arid climatic conditions have substantial potential in rehabilitating sulfidic tailings, resulting from their aggregation microstructure regulated by Fe-Si cements. Nevertheless, eco-engineered approaches for accelerating the formation of complex cementation structure remain unclear. The present study aims to investigate the microbial functions of extremophiles on mineral dissolution, oxidation, and aggregation (cementation) through a microcosm experiment containing pyrites and polysilicates, of which are dominant components in typical sulfidic tailings. Microspectroscopic analysis revealed that pyrite was rapidly dissolved and massive microbial corrosion pits were displayed on pyrite surfaces. Synchrotron-based X-ray absorption spectroscopy demonstrated that approximately 30 % pyrites were oxidized to jarosite-like (ca. 14 %) and ferrihydrite-like minerals (ca. 16 %) in talc group, leading to the formation of secondary Fe precipitates. The Si ions co-dissolved from polysilicates may be embedded into secondary Fe precipitates, while these clustered Fe-Si precipitates displayed distinct morphology (e.g., “circular” shaped in the talc group, “fine-grained” shaped in the chlorite group, and “donut” shaped in the muscovite group). Moreover, the precipitates could join together and act as cementing agents aggregating mineral particles together, forming macroaggregates in talc and chlorite groups. The present findings revealed critical microbial functions on accelerating mineral dissolution, oxidation, and aggregation of pyrite and various silicates, which provided the eco-engineered feasibility of hardpan-based technology for mine site rehabilitation.

Green‐Prepared Magnesium Silicate Sprays Enhance the Repair of Burn‐Skin Wound and Appendages Regeneration in Rats and Minipigs

AbstractBioceramics provide promising tactics for wound healing, yet the on‐shelf products are still unmet, especially for skin appendages regeneration. Herein, the inorganic magnesium silicate sprays (MSS) as mineral factors to overcome the existing challenges is proposed. Results indicate MSS can be synthesized by a green method without organic solvents, templates, calcination, and harmful by‐products. With amorphous phase, nanoscale, and high specific surface area, MSS reveal an improved pH‐responsive degradability and excellent bioactivity for cell proliferation and migration. In rats, MSS display a dose‐dependent effect on accelerating burn‐wound repair via regulating the expressions of iNOS and IL‐10 to attenuate inflammation, elevating the expressions of CD31 and α‐SMA to improve vascularization, and boosting collagen deposition without ectopic calcification. The released Mg and Si ions synergistically potentiate the expressions of Gap43, Tubb3, and K19, suggesting the regeneration of peripheral nerves and hair follicles. These superior features are further verified by comparisons with commercial products, Dermlin® and 45S5 bioglass®, in both rats and minipigs. Motivated by these findings, three MSS‐based formulations of band‐aid patch, adhesive hydrogel, and antibacterial sprays are devised for specific scenarios. Taken together, this proof‐of concept study provides a promising bioactive mineral for future clinical skin wound repair and functional appendages regeneration.

Effect of Si Ion Concentrations on the Phosphorous Ion Separation from the Solution Containing Ca, Si, and P Ions by Ion-exchange Membrane Electrodialysis

Effect of Si Ion Concentrations on the Phosphorous Ion Separation from the Solution Containing Ca, Si, and P Ions by Ion-exchange Membrane Electrodialysis

3D printed Si-CaP scaffold released SiO32- and Ca2+ to synergistically promote angiogenesis.

Structuring scaffold with both osteogenic and angiogenesis capabilities is a challenge for bone tissue engineering. Powder structured Si-CaP materials have shown excellent osteogenic properties and induction of stem cell differentiation. Our research group have successful produced 3D printed Si-CaP scaffolds by DLP technology. This study aims to explore the angiogenic effects of SiO32- and Ca2+ released by 3D printed Si-CaP scaffold, and whether there is a synergistic effect between the two ions. The 3D printed Si-CaP scaffolds were immersed in endothelial cell medium solution for 24h. The Si, Ca ion released was detected by Inductively coupled plasma-optical emission spectrometry. We used detected data as a standard to prepare the simulated solution to investigate the effect of SiO32-, Ca2+ separately. Experiment was divided into control group, Si ion group, Ca ion group and Si + Ca ion group. We evaluated different ionic effect on HUVECs viability, proliferation, migration, gene expression, and tube formation on different groups. The concentration of SiO32- was detected as 15.71 ± 0.04μg/mL, Ca2+ as 67.14 ± 0.95μg/mL. Na2SiO3 and CaCl2 were used to prepare the simulated solution. There were no statistically difference between simulated solution from ion released by scaffold. Si + Ca group promoted the gene expression significantly compared with the control group, p < .01. Expression of vascular-associated protein in Si + Ca ion group was higher than that in Si ion group, Ca ion group and control group. Si + Ca ion group significantly enhanced endothelial cell on migration and tube formation assay. The 3D printed Si-CaP scaffold can release effective physiological concentrations of Si, Ca ions. Si and Ca ions have a synergistic effect on promoting angiogenesis of HUVECs. 3D printed Si-CaP scaffold is promising in vascularized bone tissue engineering application.

A Multifunctional Hydrogel for Simultaneous Visible H2 O2 Monitoring And Accelerating Diabetic Wound Healing.

Diabetic wound is one of the chronic wounds that is difficult to heal, and effective treatment of it still confronts a great challenge. Monitoring the variation of diabetic wound microenvironment (such as hydrogen peroxide (H2 O2 )) can understand the wound state and guide the wound management. Herein, a multifunctional hydrogel with the abilities of monitoring the H2 O2 concentration, alleviating oxidative stress and promoting wound healing is developed, which is prepared by encapsulating manganese-containing bioactive glass (MnBG) and CePO4 :Tb in biocompatible gelatin methacryloyl (GelMA) hydrogel (CPT-MnBG-Gel). On the one hand, the H2 O2 -dependent fluorescence quenching effect of the CePO4 :Tb contributes to visible monitoring of the H2 O2 concentration of wounds via smartphone imaging, and the CPT-MnBG-Gel hydrogel can effectively monitor the H2 O2 level of 10.35-200µmol L-1 . On the other hand, MnBG can alleviate oxidative stress and promote the proliferation, migration and differentiation of fibroblasts and endothelial cells in vitro owing to the bioactive Mn and Si ions, and in vivo evaluation also demonstrates that the CPT-MnBG-Gel hydrogels can effectively accelerate wound healing. Hence, such multifunctional hydrogel is promising for diabetic wound management and accelerating wound healing.

A high sensitivity microbeam RBS setup for heavy elements implantation profiles analysis

This work presents a new setup that integrates heavy ion RBS with microbeam technology combined with high detection solid angle for the measurement of the depth profile and areal distribution of heavy elements in silicon using a Si microbeam. Focussed 2.4 MeV Si2+ ions were scanned over the frontal or lateral surface of silicon wafers to measure both the areal concentrations and depth profiles of all elements heavier than silicon. Tests were done on samples with Pt concentration range of 4 × 10 12–2 × 10 14 at/cm 3 that was diffused via the Pt-Silicide surface layer process from one lateral surface into the 400 µm thick Si wafers. It is important to note that employing a Si ion beam instead of the conventional He ion beam serves the purpose of not only increasing the backscattering cross section, as in well-established heavy element RBS, but also reducing pileup by eliminating scattering from the Si substrate, which is essential for sensitive analysis. This allows a significant increase in microbeam currents without increasing the count rate in large area detectors. A set of two large area PIN diodes (10x10 mm) were used in an optimized configuration resulting in 1,04 sr detection solid angle. Additionally, an appropriate microbeam collimator was used to shield the PIN diodes from events caused by forward scattering and scattering of the Si ion beam halo from different components in the reaction chamber. Lateral scans of the silicon wafer were performed by focussed Si ions, with ∼10 µm spot size and of the nA range beam currents. The RBS intensity maps containing the Pt depth profile were obtained with a sensitivity of 6.7 × 109 at/cm2.

Enhancing fentanyl antinociception and preventing tolerance with α-2 adrenoceptor agonists in rats

Fentanyl (FEN) is a potent opioid analgesic used for pain management. Opioid analgesic tolerance poses a significant challenge to the clinical utility of opioid agonists. Preventing the development of tolerance to opioid analgesia is crucial for improving its efficacy and safety. The noradrenergic system is involved in pain regulation. This study examined the effects of α-2 adrenoceptor (AR) agonists, dexmedetomidine (DEX), and xylazine (XYL) on FEN tolerance and antinociception, and their impact on μ-opioid receptor (MOR) expression in the posterior horn of the spinal cord (SC). Male rats were divided into six groups and treated with different drug combinations for three consecutive days. Analgesia tests and motor performance assessments were conducted, followed by SC analysis using immunohistochemistry (IHC). Analgesia tests revealed the development of FEN tolerance on the second day, but the groups receiving combined drugs did not develop tolerance. Instead, FEN antinociception was enhanced, with a prolonged duration of its effects. None of the drugs caused sedation or motor impairment, and SC morphology appeared normal. MOR expression levels did not differ significantly between the groups based on IHC analysis. These findings suggest that changes in the secondary messenger system may play a role in the early development of FEN tolerance. Combining drugs can prevent tolerance, while enhancing FEN's antinociceptive effects. These results have promising implications for chronic pain management; however, further research is needed to explore the molecular effects of α-2 AR agonists on FEN tolerance. Overall, this study sheds light on the mechanism of FEN tolerance and identifies potential avenues for future research.