Fentanyl Research Articles

Design and Characterization of Microemulsion System for Fentanyl citrate

This research was aimed to formulate and characterize micro-emulsion systems as a sublingual delivery system of fentanyl citrate an opioid pain medicine used for treatment of breakthrough cancer pain that is not controlled by other medicines. The three phases i.e. oil, surfactant and co-surfactant were selected on the basis of their drug solubility and their efficiency to form ME. Pseudo-ternary phase diagrams were constructed and on the basis of ME existence ranges various formulations of FC were developed. The influence of Smix ratio on the ME formation and in vitro permeation of ME through cellophane membrane was studied respectively. The optimized ME formulation C2 consists of a globule size of 96.9 nm, polydispersity index of 0.263, pH 4.18, viscosity 20.4 cps, a zeta potential of -8.5and conductance of 131.7±0.42µS. The optimized ME formulation C2 exhibited a steady state flux of about 361.92±0.57 and thus exhibiting higher drug permeation through ME for mulations. Apart from this, the formulation was also evaluated for drug content, centrifugation and stability study. The results indicate that, the investigated MEmay be used as a promising alternative for FC therapy for breakthrough pain management.

Calcined Clays from Nigeria-Properties and Performance of Supplementary Cementitious Materials Suitable for Producing Level 1 Concrete.

In this work, four naturally occurring (two kaolinite-rich and two smectite-rich) clay samples were collected from different areas around the Ashaka cement production plant, located in Gombe State, Nigeria and calcined in a laboratory. The mineralogical characterization of the clays was carried out by XRD. The hydration kinetics of the calcined clay-cement systems were monitored by isothermal calorimetry. Workability was determined using the flow table method. The reactivity of the calcined clays was determined from the solubility of Si and Al ions and the strength activity index. All calcined clays studied met the requirements of ASTM C618 for the use of natural pozzolans as a partial replacement for hydraulic cement. The metasmectite clays yielded a higher specific surface area, increased water demand, and less reactive Si and Al ions compared to the metakaolin clays. The two calcined clay groups require the addition of superplasticizer to achieve a workability class similar to the Portland cement mortar system. They can be used to replace Portland cement at replacement levels of up to 45%, in combination with limestone powder to form an LC3 cement, thereby achieving at least a "Level 1" reduction in greenhouse gas emissions.

Nanoporous boron-doped diamond produced by a combination of high-energy ion irradiation and anodization

A wide electrochemical window makes boron-doped diamond (BDD) a promising electrode material. To utilize its excellent properties, nanopore formation on the surface to increase the specific surface area is highly desirable. Although anodization has the potential to produce nanoporous structures on the surface of materials, BDD has yet to be anodized due to its high physical and chemical stability. Here, we report that high-energy Si(II) ion irradiation forms sp2 defects, which enable the anodization of BDD, and demonstrate that this anodization results in the formation of nanoporous BDD.

To Compare Isobaric Thoracic Spinal Anesthesia Versus General Anesthesia in Laparascopy Cholecystectomy

Background: The laparoscopic cholecystectomy procedure is typically carried out under general anesthesia, but regional techniques, such as low thoracic isobaric spinal anesthesia, have been used to manage patients with significant medical problem like coexisting systemic disease, who are deemed to be high risk in general anesthesia. Segmental spinal anesthesia has great outcomes in terms of post-operative discomfort, the need for analgesics, relatively fewer complications, and shorter hospital stays. Thus the aim of this study to avoid and minimize the risk of general anesthesia who does not have any significant comorbidity. So it might be a substitute for a standard laparoscopic cholecystectomy. Material and Methods: Total 60 adult patient with ASA1 & I I, 18-60 years, with normal coagulation profile, is divided into 2 groups. Group IS (Isobaric) - given 2.5 ml of isobaric preservative free bupivacaine 0.5% (levobupivacaine) + 0.5 mg of Fentanyl at T9-T10/T10-T11 into sub arachnoid space. Group GA – given general anesthesia using propofol, fentanyl citrate and atracurium besylate. After intubation, ventilation was controlled and balanced anesthesia was continued with isoflurane. After completion, neuromuscular block was anatagonized neostigmine methylsulfate and glycopyrrolate at the end of surgery. Results: Isobaric spinal anesthesia showed good control in intraoperative as well as postoperative pain control as compared to general anesthesia. In few patients, there were minor degrees of nausea, vomiting, abdominal pain, shoulder pain, patient anxiety or itchng which were treated with standard medication like fentanyl and midazolam. All patients can resume oral intake on the day of surgery. Conclusions: In conclusion, this study provide evidence that segmental spinal anesthesia can be used in place of general anesthesia in healthy individuals also.

Low donor ionization energy in Si-implanted heteroepitaxial AlN

We obtained high n-type conductivity and low donor ionization energy for an AlN film grown on SiC by Si ion implantation. The room temperature conductivity reaches 0.26 Ω−1 cm−1, and the donor ionization energy is only 112 meV, which is the best result of Si-implanted heteroepitaxial AlN. The lattice damage caused by ion implantation can be almost completely repaired by annealing at 1330 °C for 2 h. X-ray photoelectron spectroscopy (XPS) results show few O impurity in the sample. The low donor ionization energy is attributed to avoiding the introduction of O impurities and the mitigation of self-compensating effect. These results show the great potential of Si-implanted heteroepitaxial AlN for device applications.

Quantitative Raman Cross-Sections and Band Assignments for Fentanyl and Fentanyl Analogs.

Raman cross sections and spectra were measured for five synthetic opioid fentanyl analogs: fentanyl citrate, sufentanil citrate, alfentanil HCl, carfentanil oxalate, and remifentanil HCl. The measurements were performed with excitation wavelengths in the visible (532 nm) and near infrared (785 nm). In addition, density functional theory (DFT) calculations were employed to generate simulated spectra of the compounds and aid in identification of the observed spectral modes. These cross-section measurements and calculations were also used to assess results from a series of measurements of fentanyls cut with other powdered materials. These measurements are valuable for assessment of field-deployable Raman chemical sensors for detection of fentanyl and fentanyl analogs, including when mixed with other materials.

Research on the surface damage of Si+ and H+ co-implanted 6H-SiC before and after annealing

6 MeV Si ions with fluences of 2 × 1016 ions/cm2 and 400 keV H ions with fluences of 5 × 1016 ions/cm2 implantation experiments were performed for single-crystal 6H-SiC samples. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the evolutions of the surface damage and internal microstructure of these irradiated 6H-SiC samples before and after annealing. Bumps were observed on the surface of the Si+ ions irradiated samples after annealing. The internal damage caused by irradiation recovered well after annealing, and the peak damage zone disappeared after the 1200 °C annealing process. Circular bubbles occurred on the surface of the H+ ions irradiated samples, which peeled off after annealing. The morphology and distribution of bubbles and spalling on the Si+-H+ dual ion beam irradiated sample surface were more irregular as the more severe damage induced by the pre-implanted Si ions hindered the aggregation and migration of hydrogen atoms.

Combined effects of heavy ion exposure and simulated Lunar gravity on skeletal muscle

BackgroundThe limitations to prolonged spaceflight include unloading-induced atrophy of the musculoskeletal system which may be enhanced by exposure to the space radiation environment. Previous results have concluded that partial gravity, comparable to the Lunar surface, may have detrimental effects on skeletal muscle. However, little is known if these outcomes are exacerbated by exposure to low-dose rate, high-energy radiation common to the space environment. Therefore, the present study sought to determine the impact of highly charge, high-energy (HZE) radiation on skeletal muscle when combined with partial weightbearing to simulate Lunar gravity. We hypothesized that partial unloading would compromise skeletal muscle and these effects would be exacerbated by radiation exposure. MethodsFor month old female BALB/cByJ mice were -assigned to one of 2 groups; either full weight bearing (Cage Controls, CC) or partial weight bearing equal to 1/6th bodyweight (G/6). Both groups were then divided to receive either a single whole body absorbed dose of 0.5 Gy of 300 MeV 28Si ions (RAD) or a sham treatment (SHAM). Radiation exposure experiments were performed at the NASA Space Radiation Laboratory (NSRL) located at Brookhaven National Laboratory on Day 0, followed by 21 d of CC or G/6 loading. Muscles of the hind limb were used to measure protein synthesis and other histological measures. ResultsTwenty-one days of Lunar gravity (G/6) resulted in lower soleus, plantaris, and gastrocnemius muscle mass. Radiation exposure did not further impact muscle mass. 28Si exposure in normal ambulatory animals (RAD+CC) did not impact gastrocnemius muscle mass when compared to SHAM+CC (p>0.05), but did affect the soleus, where mass was higher following radiation compared to SHAM (p<0.05). Mixed gastrocnemius muscle protein synthesis was lower in both unloading groups. Fiber type composition transitioned towards a faster isoform with partial unloading and was not further impacted by radiation. The combined effects of partial loading and radiation partially mitigated fiber cross-sectional area when compared to partial loading alone. Radiation and G/6 reduced the total number of myonuclei per fiber while leading to elevated BrdU content of skeletal muscle. Similarly, unloading and radiation resulted in higher collagen content of muscle when compared to controls, but the effects of combined exposure were not additive. ConclusionsThe results of this study confirm that partial weightbearing causes muscle atrophy, in part due to reductions of muscle protein synthesis in the soleus and gastrocnemius as well as reduced peripheral nuclei per fiber. Additionally, we present novel data illustrating 28Si exposure reduced nuclei in muscle fibers despite higher satellite cell fusion, but did not exacerbate muscle atrophy, CSA changes, or collagen content. In conclusion, both partial loading and HZE radiation can negatively impact muscle morphology.

Cellular Uptake of Modified Mesoporous Bioactive Glass Nanoparticles for Effective Intracellular Delivery of Therapeutic Agents.

There has recently been a surge of interest in mesoporous bioactive glass nanoparticles (MBGNs) as multi-functional nanocarriers for application in bone-reconstructive and -regenerative surgery. Their excellent control over their structural and physicochemical properties renders these nanoparticles suitable for the intracellular delivery of therapeutic agents to combat degenerative bone diseases, such as bone infection, or bone cancer. Generally, the therapeutic efficacy of nanocarriers strongly depends on the efficacy of their cellular uptake, which is determined by numerous factors including cellular features and the physicochemical characteristics of nanocarriers, particularly surface charge. In this study, we have systematically investigated the effect of the surface charge of MBGNs doped with copper as a model therapeutic agent on cellular uptake by both macrophages and pre-osteoblast cells involved in bone healing and bone infections to guide the future design of MBGN-based nanocarriers. Cu-MBGNs with negative, neutral, and positive surface charges were synthesized and their cellular uptake efficiency was assessed. Additionally, the intracellular fate of internalized nanoparticles along with their ability to deliver therapeutic cargo was studied in detail. The results showed that both cell types internalized Cu-MBGNs regardless of their surface charge, indicating that cellular uptake of nanoparticles is a complex process influenced by multiple factors. This similarity in cellular uptake was attributed to the formation of a protein corona surrounding the nanoparticles when exposed to protein-rich biological media, which masks the original nanoparticle surface. Once internalized, the nanoparticles were found to mainly colocalize with lysosomes, exposing them to a more compartmentalized and acidic environment. Furthermore, we verified that Cu-MBGNs released their ionic components (Si, Ca, and Cu ions) in both acidic and neutral environments, leading to the delivery of these therapeutic cargos intracellularly. The effective internalization of Cu-MBGNs and their ability to deliver cargos intracellularly highlight their potential as intracellular delivery nanocarriers for bone-regenerative and -healing applications.

Evaluation of polyanionic cyclodextrins as high affinity binding scaffolds for fentanyl

Cyclodextrins (CDs) have been previously shown to display modest equilibrium binding affinities (Ka ~ 100–200 M-1) for the synthetic opioid analgesic fentanyl. In this work, we describe the synthesis of new CDs possessing extended thioalkylcarboxyl or thioalkylhydroxyl moieties and assess their binding affinity towards fentanyl hydrochloride. The optimal CD studied displays a remarkable affinity for the opioid of Ka = 66,500 M−1, the largest value reported for such an inclusion complex to date. One dimensional 1H Nuclear Magnetic Resonance (NMR) as well as Rotational Frame Overhauser Spectroscopy (2D-ROESY) experiments supported by molecular dynamics (MD) simulations suggest an unexpected binding behavior, with fentanyl able to bind the CD interior in one of two distinct orientations. Binding energies derived from the MD simulations work correlate strongly with NMR-derived affinities highlighting its utility as a predictive tool for CD candidate optimization. The performance of these host molecules portends their utility as platforms for medical countermeasures for opioid exposure, as biosensors, and in other forensic science applications.

Sustained release silicon from 3D bioprinting scaffold using silk/gelatin inks to promote osteogenesis

Repairing extensive bone defects that cannot self-heal has been a clinical challenge. The construction of scaffolds with osteogenic activity through tissue engineering can provide an effective strategy for bone regeneration. This study utilized gelatin, silk fibroin, and Si3N4 as scaffold materials to prepare silicon-functionalized biomacromolecules composite scaffolds using three-dimensional printing (3DP) technology. This system delivered positive outcomes when Si3N4 levels were 1 % (1SNS). The results showed that the scaffold had a porous reticular structure with a pore size of 600–700 μm. The Si3N4 nanoparticles were distributed uniformly in the scaffold. The scaffold could release Si ions for up to 28 days. In vitro experiments showed that the scaffold had good cytocompatibility, promoting the osteogenic differentiation of mesenchymal stem cells (MSCs). In vivo experiments on bone defects in rats showed that the 1SNS group facilitated bone regeneration. Therefore, the composite scaffold system showed potential for application in bone tissue engineering.

Adequacy of Anaesthesia for Nociception Detection during Vitreoretinal Surgery.

Vitreoretinal surgery (VRS) is one of the most widely performed precise procedures in ophthalmic surgery; the majority of cases are carried out under regional anaesthesia (RA) only. However, in specific situations (such as when the patient fails to cooperate with the operator for various reasons), general anaesthesia (GA), alone or in combination with GA (combined general-regional anaesthesia, CGR), is the only safe way to perform VRS. While monitoring the efficacy of an intraoperative rescue opioid analgesia (IROA) during surgery (assessing the adequacy of anaesthesia (AoA)) may be challenging, the surgical pleth index (SPI) is a useful tool for detecting the reaction to noxious stimuli and allows for the rational titration of opioid analgesics (AO) during surgery. The current study investigated the influence of the SPI-based titration of fentanyl (FNT) in combination with various pre-emptive analgesia (PA) techniques on intraoperative pain perception during various stages of VRS performed under AoA. A total of 176 patients undergoing VRS under GA were enrolled in the study. They were randomly assigned to one of the five following study arms: Group GA (control group)-patients who received general anaesthesia alone; Group PBB-GA with preprocedural peribulbar block (with 0.5% bupivacaine and 2% lidocaine); Group T-GA with preventive, topical 2% proparacaine; Group M-GA with a preprocedural intravenous infusion of 1.0 g of metamizole; and Group P-GA with a preprocedural intravenous infusion of 1.0 g of paracetamol. The whole procedure was divided in four stages: Stage 1 and 2-preoperative assessment, PA administration, and the induction of GA; Stage 3-intraoperative observation; Stage 4-postoperative observation. the SPI values were monitored during all stages. The occurrence of nociception (expressed as ∆SPI >15) during various manipulations in the surgical field was observed, as were cumulative doses of rescue analgesia, depending on the PA administered. During the course of VRS, rescue FNT doses varied depending on the stage of surgery and the group investigated. The majority of patients, regardless of their group allocation, needed complementary analgesia during trocar insertion, with Group GA patients requiring the highest doses. Likewise, the highest cumulative doses of IROA were noted during endophotocoagulation in Group GA. Preventive PBB and topical anaesthesia were proven to be most efficient in blunting the response to speculum installation, while topical anaesthesia and paracetamol infusion were shown to be more efficient analgesics during endophotocoagulation than other types used PA. In the performed study, none of the PA techniques used were superior to GA with FNT dosing under the SPI with respect to providing efficient analgesia throughout the whole surgery; there was a necessity to administer a rescue OA dose in both the control and investigated groups.

Homoepitaxial Si-doped Gallium Oxide films by MOCVD with tunable electron concentrations and electrical properties

Doping technology with stable carrier concentration regulation is a guarantee for optimizing β-Ga2O3-based high-power electronic devices and optoelectronic devices. In this study, β-Ga2O3 homoepitaxial epitaxial films with stable and tunable electron concentrations were grown on Fe-doped (010)-oriented β-Ga2O3 substrates by using metal-organic chemical vapor deposition (MOCVD). XRD shows that the basic bulk properties of β-Ga2O3 film, i. e. the structure and crystal orientation, are stable with low Si-doping, however, its electrical properties vary remarkably depending on concentrations of Si ions incorporated by Si source flow rate during the film growth process. Hall measurement is utilized to confirm high-quality β-Ga2O3 films with tunable electron concentration of 1017–1019 cm−3. As a consequence, the electron concentration-dependent behavior of β-Ga2O3 Schottky barrier diodes (SBDs) was studied. The β-Ga2O3 SBDs exhibited better forward current output electrical performance with reduction in built-in potential difference (Vbi) from 2.4 V to 0.3 V and on-resistance (Ron) from 257 Ω cm to 26 Ω cm. Our results suggest that stable and tunable electron concentration provides high-quality material assurance for constructing power electronic devices of Ga2O3.

Novel antibacterial and apatite forming restorative composite resin incorporated with hydrated calcium silicate

BackgroundWhite Portland cement is a calcium silicate material. It exhibits antibacterial properties and is biocompatible. In addition, calcium silicate-based materials are known to release calcium ions and form apatite. The purpose of this study was to develop a novel bioactive restorative resin composite with antibacterial and apatite forming properties to prevent tooth caries at the interface of teeth and restorative materials, by incorporation of hydrated calcium silicate (hCS) derived from white Portland cement.MethodsTo prepare the experimental composite resins, a 30 wt% light-curable resin matrix and 70 wt% filler, which was mixed with hCS and silanized glass powder were prepared in following concentrations: 0, 17.5, 35.0, and 52.5 wt% hCS filler. The depth of cure, flexural strength, water sorption, solubility, and antibacterial effect were tested. After immersion in artificial saliva solution for 15, 30, 60, and 90 days, ion concentration by ICP-MS and apatite formation using SEM-EDS, Raman spectroscopy and XRD from experimental specimens were analyzed.ResultsAll experimental groups showed clinically acceptable depths of cure and flexural strength for the use as the restorative composite resin. Water sorption, solubility, released Ca and Si ions increased with the addition of hCS to the experimental composite resin. Experimental groups containing hCS showed greater antibacterial effects compared with the 0 wt% hCS filler group (p < 0.05). The 52.5 wt% hCS filler group produced precipitates mainly composed of Ca and P detected as hydroxyapatite after immersion in artificial saliva solution for 30, 60, and 90 days.ConclusionsThis results show that composite resins containing hCS filler is effective in antibacterial effects. hCS has also apatite formation ability for reducing gap size of microleakage by accumulating hydroxyapatite precipitates at the restoration-tooth interface. Therefore, novel composite resin containing hCS is promising bioactive resin because of its clinically acceptable physiochemical properties, antibacterial properties, and self-sealing potential for prevention of microleakage for longer usage of restorations.

Bis(2,4,6-trichlorophenyl)oxalate-based chemically initiated electron exchange chromogenic reaction system for colorimetric detection of fentanyl and norfentanyl

Bioenzymes or nanoenzymes-involved aqueous chromogenic systems play a central role in colorimetric analysis. A lack of high and general chromogenic reactions that work in a hydrophobic medium has hampered the development of colorimetric methods for the detection of many hydrophobic analytes. To address this challenge, a series of chemically initiated electron exchange chromogenic (CIEEC) reaction systems are presented that functions in an ethanol–water mixture solvent. The resulting CIEEC systems are based on the oxidation capacity of biradical intermediate produced by the reaction between bis(2,4,6-trichlorophenyl)oxalate (TCPO) and H2O2, and it oxidizes various chromogenic substrates such as 3, 3′, 5, 5′-tetramethylbenzidine (TMB), o-phenylenediamine, diazoaminobenzene, and 2,2ʹ-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) to create colored products. Taking advantage of the catalytic effect of fentanyl (FTN) and norfentanyl (NFTN), we fabricate a visual colorimetric assay based on the TCPO-H2O2-TMB CIEEC reaction system, and the resulting sensitivity is comparable to that of the reported colorimetric assays for FTN. Moreover, the present assay is capable of detecting both FTN and NFTN in human urine samples.

Multifunctional chitosan/alginate hydrogel incorporated with bioactive glass nanocomposites enabling photothermal and nitric oxide release activities for bacteria-infected wound healing

It is highly desirable to develop novel multifunctional wound dressing materials capable of delivering active molecules capable of resolving bacterial infections and replenishment of appropriate growth factors for bacteria-infected wound healing. Polysaccharides have numerous biomedical benefits and have been widely used to construct biomaterial scaffolds. Herein, multifunctional chitosan/alginate hydrogel decorated with β-cyclodextrin (β-CD) modified polydopamine (PDA)-bioactive glass (BG) nanoparticles (NPs) integrating photothermal performance and nitric-oxide release activities for the treatment of bacterially infected wounds is presented. As the NO precursor N,N′-di-sec-butyl-N,N′-dinitroso-1,4-phenylenediamine (BNN6) encapsulated into the hydrophobic cavity of β-CD on the PDA-coated BG NPs, the resultant NO@CD-PDA/BG NPs, are imparted with the feature of NIR triggered NO release and desired PTT/NO synergetic antibacterial effects. Furthermore, the release of NO, Ca, and Si ions from the NO@CD-PDA/BG NPs, has the benefit of regulating inflammation, promoting fibroblast proliferation, and stimulating angiogenesis. Besides, the chitosan/alginate hydrogel scaffolds provided a suitable microenvironment to accelerate wound healing. By applying the multifunctional chitosan/alginate nanocomposite hydrogel to S. aureus-infected full-thickness skin defect mouse model, the authors demonstrated that chitosan/alginate nanocomposite hydrogel has multiple functions in preventing bacterial infections, accelerating angiogenesis and wound regeneration, indicating promising application in wound healing.

Silica-Based Advanced Nanoparticles For Treating Ischemic Disease.

Recently, various attempts have been made to apply diverse types of nanoparticles in biotechnology. Silica nanoparticles (SNPs) have been highlighted and studied for their selective accumulation in diseased parts, strong physical and chemical stability, and low cytotoxicity. SNPs, in particular, are very suitable for use in drug delivery and bioimaging, and have been sought as a treatment for ischemic diseases. In addition, mesoporous silica nanoparticles have been confirmed to efficiently deliver various types of drugs owing to their porous structure. Moreover, there have been innovative attempts to treat ischemic diseases using SNPs, which utilize the effects of Si ions on cells to improve cell viability, migration enhancement, and phenotype modulation. Recently, external stimulus-responsive treatments that control the movement of magnetic SNPs using external magnetic fields have been studied. This review addresses several original attempts to treat ischemic diseases using SNPs, including particle synthesis methods, and presents perspectives on future research directions.

Oral transmucosal fentanyl citrate analgesia in prehospital trauma care: an observational cohort study

BackgroundPain is one of the major prehospital symptoms in trauma patients and requires prompt management. Recent studies have reported insufficient analgesia after prehospital treatment in up to 43% of trauma patients, leaving significant room for improvement. Good evidence exists for prehospital use of oral transmucosal fentanyl citrate (OTFC) in the military setting. We hypothesized that the use of OTFC for trauma patients in remote and challenging environment is feasible, efficient, safe, and might be an alternative to nasal and intravenous applications.MethodsThis observational cohort study examined 177 patients who were treated with oral transmucosal fentanyl citrate by EMS providers in three ski and bike resorts in Switzerland. All EMS providers had previously been trained in administration of the drug and handling of potential adverse events.ResultsOTFC caused a statistically significant and clinically relevant decrease in the level of pain by a median of 3 (IQR 2 to 4) in NRS units (P < 0.0001). Multiple linear regression analysis showed a significant absolute reduction in pain, with no differences in all age groups and between genders. No major adverse events were observed.ConclusionsPrehospital administration of OTFC is safe, easy, and efficient for extrication and transport across all age groups, gender, and types of injuries in alpine environments. Side effects were few and mild. This could provide a valuable alternative in trauma patients with severe pain, without the delay of inserting an intravenous line, especially in remote areas, where fast action and easy administration are important.

Effect of pre-irradiation defects on helium trapping and diffusion in RAFM steel

In order to analyze the effect of pre-irradiation defects on helium trapping and diffusion behaviors in detail by slow positron beam, Si ion with high energies (300 keV and 6 MeV) and 100 eV helium plasma were sequentially introduced into reduced activation ferritic/martensitic steel. Massive microscopic defects were observed in Si ion irradiated specimens. Low energy helium (∼100 eV) atoms could diffuse into much deeper region in metals without displacement damage. In the diffusion process of helium atoms, they would be trapped by the Si-ion pre-irradiation defects. The formation of He-vacancy complexes would affect the annihilation of positrons with the electrons in pre-irradiation defects and decrease the S parameters. The shallow region defects induced by 300 keV irradiation have more obvious advantage of hindering the diffusion of helium over the deep defects than that in 6 MeV irradiation. Thus, the pre-introduced defects can trap effectively helium atoms and hinder their diffusion.

60 MeV Si ion beam irradiation induced modifications in the structural and optical properties of Li doped NiO thin films

Li doped NiO films grown on FTO substrates through spin coating technique were irradiated using 60 MeV Si ions. The films were investigated via several approaches including grazing incidence X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectroscopy, atomic force microscopy, micro-Raman and UV–visible spectroscopy. The crystalline nature of films declines with the initial face-centered cubic structure for 1x1014 ions cm−2 owing to the energy loss of Si ions in a Li doped NiO (Li:NiO) lattice during the generation of defects. The crystallite size of samples was evaluated using Scherrer’s equation. The vibrational modes were investigated via micro-Raman analysis. AFM topography was recorded for pristine and Si ion irradiated films. The ion fluence of Si ion in the used energy range lowers the transmittance Li:NiO films as compared to the pristine.