Application of cold argon plasma on germination, root length, and decontamination of soybean cultivars.

Applying cold discharge plasma can potentially alter plants' germination characteristics by triggering their physiological activities. As a main crop in many countries, soybean was examined in the present study using cultivars such as Arian, Katoul, Saba, Sari, and Williams in a cold argon plasma. This study has been motivated by the importance of plant production worldwide, considering climate change and the increasing needs of human populations for food. This study was performed to inspect the effect of cold plasma treatment on seed germination and the impact of argon plasma on microbial decontamination was investigated on soybeans. Also, the employed cultivars have not been studied until now the radicals generated from argon were detected by optical emission spectrometry (OES), and a collisional radiative model was used to describe electron density. The germination properties, including final germination percentage (FGP), mean germination time (MGT), root length, and electrical conductivity of biomolecules released from the seeds, were investigated after the plasma treatments for 30, 60, 180, 300, and 420 s. The decontamination effect of the plasma on Aspergillus flavus (A.flavus) and Fusarium solani (F.solani) was also examined. The plasma for 60 s induced a maximum FGP change of 23.12 ± 0.34% and a lowest MGT value of 1.40 ± 0.007 days. Moreover, the ultimate root length was 56.12 ± 2.89%, in the seeds treated for 60 s. The plasma exposure, however, failed to yield a significant enhancement in electrical conductivity, even when the discharge duration was extended to 180 s or longer. Therefore, the plasma duration of 180 s was selected for the blotter technique. Both fungi showed successful sterilization; their infectivity inhibition was 67 ± 4 and 65 ± 3.1%, respectively. In general, the cold plasma used for soybeans in the present study preserved their healthy qualities and reduced the degree of fungal contamination.

Efficacy of surgical treatments for the management of solitary rectal ulcer syndrome: a network meta-analysis.

AIM: Solitary rectal ulcer syndrome (SRUS) is a benign and poorly understood disorder with complex management. Typical symptoms include straining during defaecation, rectal bleeding, tenesmus, mucoid secretion, anal pain and a sense of incomplete evacuation. Diagnosis is based on characteristic clinical symptoms and endoscopic/histological findings. Several treatments have been reported in the literature with variable ulcer healing rates. This study aimed to evaluate the efficacy of different treatments for SRUS. MATERIALS AND METHODS: A systematic review and network meta-analysis were performed according to the PRISMA guidelines. Studies in English, French and Spanish languages were included. Papers written in other languages were excluded. Other exclusion criteria were reviews, case reports or clinical series enrolling less than five patients, study duplications, no clinical data of interest and no article available. A systematic literature search was conducted from January 2000 to March 2024 using the following databases: PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and Scopus. The biases of the studies were assessed using the Newcastle-Ottawa scale or the Jadad scale when appropriate. Types of treatment and their efficacy for the cure of SRUS were collected and critically assessed. The study's primary outcome was to estimate the rate of patients with ulcer healing. RESULTS: A total of 22 studies with 911 patients (men 361, women 550) diagnosed with SRUS were analysed in the final meta-analysis. The pooled effect estimates of treatment efficacy revealed that surgery showed the highest ulcer healing rate (70.5%; 95% CI 0.57-0.83). Surgery was superior in the cure of ulcers with respect to medical therapies and biofeedback (OR 0.09 and OR 0.14). CONCLUSION: Solitary rectal ulcer syndrome is a challenging clinical entity to manage. Proficient results have been reported with the surgical approach, suggesting its positive role in cases refractory to medical and biofeedback therapy. Further studies in homogeneous populations are required to evaluate the efficacy of surgery in this setting. (PROSPERO registration number CRD42022331422).

Effectiveness and Safety of Argon Plasma Coagulation in Patients with Haemoptysis Caused by an Endobronchial Malignancy.

INTRODUCTION: Patients with central neoplasms and haemoptysis show low survival rates. Symptom control without recurrence 48 h after bronchoscopic interventions may improve the prognosis of these patients. Bronchoscopic argon plasma coagulation (APC) is a useful technique for endobronchial management of haemoptysis in patients with central malignancies. Nevertheless, limited data are available in the literature on its efficacy and safety and the main predictors of success are still unclear. METHODS: An observational, prospective, single-centre cohort study was carried out to assess the efficacy (i.e., immediate bleeding cessation without recurrence during the following 48 h) of bronchoscopic APC in the treatment of patients with haemoptysis caused by endobronchial malignancies and the main predictors of success. RESULTS: A total of 76 patients with median age 75 years (interquartile range: 65-79) were enrolled. 67 (88.2%) patients had bleeding cessation without recurrence 48 h after bronchoscopic APC. A low rate of non-serious adverse events (5.3%) was recorded and a low (7.6%) recurrence rate of haemoptysis at 3.5 months after the procedure was also shown. No clinical, demographic and endoscopic variables related to a successful procedure at 48 h were found. CONCLUSION: This study demonstrates that bronchoscopic APC is an effective procedure in the treatment of patients with haemoptysis caused by endobronchial malignancies, regardless of the clinical characteristics of the patients, the endoscopic and histological features of the neoplasm and the severity of the symptom. Furthermore, it shows a low rate of complications and long-term efficacy in bleeding control.

Comparing the effects of argon plasma coagulation and interferon therapy in patients with vaginal intraepithelial neoplasia: a single-center retrospective study.

PURPOSE: This study aimed to evaluate the clinical efficacy and safety of argon plasma coagulation (APC) therapy and interferon therapy in patients with grade I and II vaginal intraepithelial neoplasia (VaIN). METHODS: A total of 112 patients with VaIN were diagnosed via colposcopy-induced biopsy and classified into the APC group (n = 77) and interferon group (n = 35). Clinical data including age, grade, symptoms, historical or concomitant neoplasia of the lower genital tract, indications for hysterectomy, pregnancy history, cytology, human papillomavirus (HPV) subtype, treatment modalities, and clinical outcomes were analyzed, retrospectively. Complications and clinical outcomes were assessed at 6- and 12-month follow-ups. RESULTS: There was no significant difference in the HPV clearance rate between the APC (53.42%) and interferon (33.33%) groups at 6 months after treatment. However, the 12-month follow-up of the APC group showed a significantly higher HPV clearance rate as compared to the interferon group (87.67% vs. 51.52%, P < 0.05). The APC group exhibited a significantly higher cure rate (79.22% vs. 40.0%) and lower persistence rate (12.99% vs. 37.14%) than the interferon group (P < 0.05). Adverse reaction analysis revealed that the primary reaction in the APC group was vaginal drainage, in contrast to the increased vaginal discharge in the interferon group; though the difference was significant (68.83% vs. 28.57%, P < 0.05), no serious complications were observed. CONCLUSIONS: Treatment with APC is a safe and more effective procedure against VaIN I and II, compared to interferon. APC may serve as a viable alternative to other physiotherapies.

Comparative clinical feasibility of antireflux mucosectomy and antireflux mucosal ablation in the management of gastroesophageal reflux disease: Retrospective cohort study.

OBJECTIVES: No definitive treatment has been established for refractory gastroesophageal reflux disease (GERD). Antireflux mucosectomy (ARMS) and antireflux mucosal ablation (ARMA) using argon plasma coagulation are promising methods. However, no study has compared these two. This study compared the efficacy and safety of the two procedures. METHODS: This multicenter, retrospective, observational study included 274 patients; 96 and 178 patients underwent ARMA and ARMS, respectively. The primary outcome was subjective symptom improvement based on GERD questionnaire (GERDQ) scores. The secondary outcomes included changes in the presence of Barrett's esophagus, Los Angeles grade for reflux esophagitis, flap valve grade, and proton pump inhibitor withdrawal rates. RESULTS: The ARMS group had higher baseline GERDQ scores (10.0 vs. 8.0, P < 0.001) and a greater median postprocedure improvement than the ARMA group (4.0 vs. 2.0, P = 0.002), and even after propensity score matching adjustment, these findings remained. ARMS significantly improved reflux esophagitis compared with ARMA, with notable changes in Los Angeles grade (P < 0.001) and flap valve grade scores (P < 0.001). Improvement in Barrett's esophagus was comparable between the groups (P = 0.337), with resolution rates of 94.7% and 77.8% in the ARMS and ARMA groups, respectively. Compared with the ARMA group, the ARMS group experienced higher bleeding rates (P = 0.034), comparable stricture rates (P = 0.957), and more proton pump inhibitor withdrawals (P = 0.008). CONCLUSIONS: Both ARMS and ARMA showed improvements in GERDQ scores, endoscopic esophagitis, flap valve grade, and the presence of Barrett's esophagus after the procedures. However, ARMS demonstrated better outcomes than ARMA in terms of both subjective and objective indicators.

Efficient Transformation of Water Vapor into Hydrogen by Dielectric Barrier Discharge Loaded with Bamboo Carbon Bed Structured by Fibrous Material.

A new method of efficiently transforming water vapor into hydrogen was investigated by dielectric barrier discharge (DBD) loaded with bamboo carbon bed structured by fibrous material in an argon medium. Hydrogen productivity was measured in three different reactors: a non-loaded DBD (N-DBD), a bamboo carbon (BC) bed DBD (BC-DBD), and a quartz wool (QW)-loaded BC DBD (QC-DBD). The effects of the quality ratio of BC to QW and relative humidity on hydrogen productivity were also investigated in QC-DBD at various flow rates. The reaction process and mechanism were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, N2 physisorption experiments, infrared spectroscopy, and optical emission spectroscopy. A new reaction pathway was developed by loading BC into the fibrous structured material to activate the reaction molecules and capture the O-containing groups in the DBD reactor. A hydrogen productivity of 17.3 g/kWh was achieved at an applied voltage of 5 kV, flow rate of 4 L/min, and 100% relative humidity (RH) in the QC-DBD with a quality ratio of BC to QW of 3.0.

Comparison of effect of machine muteness to reduce noise anxiety vs regular settings on patient compliance during pan-retinal photocoagulation.

This Quasi Experimental study was conducted at Major Eye Clinic, Gujranwala, from January to December 2022, to study the effect of muting the sound of Argon Laser machine on patient compliance and the pain felt during pan-retinal photocoagulation (PRP). Eighty patients were included in the study with proliferative diabetic retinopathy (PDR), retinal breaks, lattice and myopic fundus degenerations for which PRP was performed. A total of 80 patients were enrolled, who were divided in two groups with 40 patients in each group. Group A patients received muted machine settings, while group B underwent regular PRP. The mean age was 54.6±3.4 years. Sixty-eight (85%) cases were of PDR, 4 (5%) of retinal breaks, 3 (3.75%) of lattice degenerations associated with breaks, and 5 (6.25%) of laser barrage. In group A, 28 (70%) patients had grade 1 and grade 2 pain score, while in group B, 26 (65%) had grade 3 and grade 4 pain score. It was concluded that by eliminating machine sound, noise anxiety can be greatly reduced ensuring better patient cooperation.

Audiometric and Vestibular Function after Classic and Reverse Stapedotomy.

Background and Objectives: Besides classical stapedotomy, reverse stapedotomy has been used for many years in the management of otosclerosis. Our study aims to investigate whether reversing the surgical steps in stapedotomy impacts vestibular function and hearing improvement. Materials and Methods: A cohort of 123 patients underwent either classic or reverse stapedotomy procedures utilizing a fiber-optic argon laser. Audiological assessments, following the guidelines of the Committee on Hearing and Equilibrium, were conducted, including pure tone average, air-bone (AB) gap, overclosure, and AB gap closure. Vestibular evaluation involved pre- and postoperative comparison of rotatory test parameters, including frequency, amplitude, and slow phase velocity of nystagmus. Results: The study demonstrated an overall median overclosure of 3.3 (3.3, 5.0) dB and a mean AB gap closure of 20.3 ± 8.8 dB. Postoperative median AB gap was 7.5 (7.5, 11.3) dB in the reverse stapedotomy group and 10.0 (10.0, 12.5) dB in the classic stapedotomy group. While overclosure and AB gap closure were marginally superior in the reverse stapedotomy group, these differences did not reach statistical significance. No significant disparities were observed in the frequency, slow phase velocity, or amplitude of nystagmus in the rotational test. Conclusions: Although not always possible, reverse stapedotomy proved to be a safe surgical technique regarding postoperative outcomes. Its adoption may mitigate risks associated with floating footplate, sensorineural hearing loss, and incus luxation/subluxation, while facilitating the learning curve for less experienced ear surgeons.

Management of circumscribed choroidal hemangioma at a tertiary care center.

PURPOSE: To review long-term outcomes of circumscribed choroidal hemangioma (CCH). METHODS: Hospital charts of all CCH cases diagnosed from 2008 to 2019 were retrospectively reviewed. RESULTS: All 172 patients were managed with either observation, transpupillary thermotherapy, argon laser photocoagulation, photodynamic therapy, plaque brachytherapy or stereotactic radiosurgery. The most common 3 modes of management were clinical observation (30.2%), transpupillary thermotherapy (52.9%) and argon laser photocoagulation (8.7%). Median follow-up time was 10 months (range: 3, 160). Anatomical outcomes were stable in 87.1% of observation group and improved in 60.5% of thermotherapy group. Quantified optical coherence tomography angiography findings showed statistical differences in vascular and perfusion densities in fellow eyes of hemangioma patients. CONCLUSION: Circumscribed choroidal hemangioma can be treated in various ways. Transpupillary thermotherapy is an anatomically effective treatment in selected cases. The diagnosis of CCH may have vascular implications in fellow eyes of the patients.

Ab initio calculations of the interaction potentials and thermodynamic functions for ArN and ArN.

Argon compounds play an important role in the mass spectrometry with inductively coupled plasma and other applications. At the same time, there is a little knowledge of their electronic terms and thermodynamic functions due to the complexity of experimental observations. In this work, the ab initio simulations are performed to obtain the interatomic interaction potentials for the ground and excited states of ArN and ArN+ . Using these potentials, the vibrational-rotational partition functions and thermodynamic properties in the gas phase are calculated for these molecules at the temperature range of 298.15-10,000 K. The errors of the thermodynamic functions associated with the approximation of interatomic interaction potentials are estimated.

Ion spectroscopy in methane activation.

This review is devoted to ion spectroscopy studies of complexes relevant for the understanding of methane activation with metal ions and clusters. Methane activation starts with the formation of a complex with a metal ion. The degree of the interaction between an intact methane molecule and the ion can be monitored by the perturbations of C-H stretch vibrations in the methane molecule. Binding mediated by the electrostatic interaction results in a η3 type coordination of methane. In contrast, binding governed by orbital interactions results in a η2 type coordination of methane. We further review the spectroscopic characterization of activation products of metal-methane reactions, such as the metal-carbene and carbyne products resulting from the interaction of selected 5d metals with methane. The focus of recent research in the field has shifted towards the investigation of interactions between methane and metal clusters. We show examples highlighting that metal clusters can be more reactive in methane activation reactions.

Enhancement of temperature-modulated NbO2-based relaxation oscillator via interfacial and bulk treatments.

This work demonstrates oscillation frequency modulation in a NbO2-based relaxation oscillator device, in which the oscillation frequency increases with operating temperature and source voltage, and decreases with load resistance. An annealing-induced oxygen diffusion at 373 K was carried out to optimize the stoichiometry of the bulk NbO2to achieve consistent oscillation frequency shift with device temperature. The device exhibits stable self-sustained oscillation in which the frequency can be modulated between 2 and 33 MHz, and a wider operating voltage range can be obtained. An additional surface treatment step was employed during fabrication to reduce the surface roughness of the bottom electrode and to remove surface contaminants that affect the interfacial properties of the device. The device frequency tunability coupled with high oscillating frequency and high endurance capability of more than 1.5 × 108cycles indicates that the Pt/NbO2/Pt device is particularly suitable for applications in an oscillatory neural network.

Radiofrequency ablation versus hybrid argon plasma coagulation in Barrett's esophagus: a prospective randomised trial.

INTRODUCTION: Radiofrequency ablation (RFA) and hybrid argon plasma coagulation (H-APC) are established thermal ablation techniques for eradicating Barrett's esophagus after endoscopic resection. This study aimed to compare RFA with H-APC in relation to safety, effectiveness and eradication rates. METHODS: After endoscopic resection, patients were randomly assigned to H-APC or RFA. A simplified H-APC technique was applied at 60 W. RFA was used with a 90° focal catheter and a simplified protocol of 12 J/cm2 × 3 or with a Halo 360° balloon and 10 J/cm2/cleaning/10 J/cm2. Eradication rates and adverse events were recorded. Patients received follow-up examinations after 3, 6, 12 and 24 months. RESULTS: One hundred and one patients were finally included in the study (RFA N = 47, H-APC N = 54). The median follow-up period for short-term was 6.0 (CI 5.4-6.9) months and for long term 21 (CI 19.2.5-22.7) months. In total 211 ablations were performed. The eradication rates after long-term follow-up were 74.2% in the RFA group and 82.9% in the H-APC group. Post-interventional pain was significantly greater in the RFA group, with a mean score of 4.56/10 and duration of 7.54 days, in comparison with a mean score of 2.07/10 over 3.59 days in the H-APC group. Stenoses requiring intervention were noted in 3.7% of patients in the H-APC arm and 14.9% of those in the RFA arm. CONCLUSIONS: Both ablation techniques have good results in relation to the eradication rate, with a slightly better outcome in the H-APC group. The severity and duration of pain were significantly greater in the RFA group.

Argon Plasma Coagulation of Gastric Inlet Patches of the Cervical Esophagus Relieves Vocal and Respiratory Symptoms in Selected Patients.

OBJECTIVES: Argon plasma coagulation (APC) of gastric inlet patches of the cervical esophagus (GIP) has been shown to relieve the globus sensation. This study aimed to investigate the long-term effects of APC therapy on a variety of laryngopharyngeal symptoms. METHODS: Patients with laryngopharyngeal symptoms who had undergone endoscopic GIP eradication via APC therapy were eligible for a retrospective observational cohort study. Symptom relief was assessed by a five-grade scale during a structured interview. Statistical analysis included ANOVA, the chi-squared and t-test. RESULTS: A total of 45 patients (61.0 (52.0; 69.0) years, 26 (57.8%) female) were included after a follow-up time of 85.0 (55.3; 111.0) months. Symptoms included dysphagia (56.0%), dysphonia (51.0%), hoarseness (76.0%), the necessity of throat clearing (73.0%), globus sensation (56.0%) and heartburn (71.0%). Complete GIP eradication was achieved after one session in 25 (55.6%), repetitive sessions were needed in the remaining cases. Fourteen patients (31.1%) reported a very strong, 11 (24.4%) a strong and 8 patients (17.8%) an intermediate improvement; five patients did not benefit. The most apparent improvement was seen regarding hoarseness (from 2.6 ± 1.7 to 1.2 ± 1.3), the necessity of throat clearing (from 2.6 ± 1.7 to 1.1 ± 1.3), globus sensation (from 2.0 ± 1.9 to 0.9 ± 1.3) and heartburn (from 2.5 ± 1.8 to 1.4 ± 1.6). Adverse events included post-endoscopic pain (n = 6, 13.3%) and purulent pharyngitis (n = 2, 4.4%). CONCLUSIONS: The APC therapy of GIP is safe and leads to long-term relief of laryngopharyngeal symptoms in carefully selected patients.

Histological, haematological, and thyroid hormones toxicity of female rats orally exposed to CuO/ZnO core/shell nanoparticles synthesized by Ar plasma jets.

Advancements in nanomedicine helped scientists design a new class of nanoparticles known as hybrid nanoparticles (core/shell) for diagnostic and therapeutic purposes. An essential requirement for the successful use of nanoparticles in biomedical applications is their low toxicity. Therefore, toxicological profiling is necessary to understand the mechanism of nanoparticles. The current study aimed to assess the toxicological potential of CuO/ZnO core/shell nanoparticles with a size of 32 nm in Albino female rats. In vivo toxicity was evaluated by oral administration of 0, 5, 10, 20, and 40 (mg/L) of CuO/ZnO core/shell nanoparticles to a female rate for 30 consecutive days. During the time of treatment, no deaths were observed. The toxicological evaluation revealed significant (p < 0.01) alteration in white blood cells (WBC) at a 5 (mg/L) dose. Also, increase in red blood cells (RBC) at 5, 10 (mg/L) doses, while hemoglobin (Hb) levels and hematocrit (HCT) increased at all doses. This maybe indicates that the CuO/ZnO core/shell nanoparticles stimulated the rate of blood corpuscle generation. The anaemia diagnostic indices (mean corpuscular volume MCV and mean corpuscular haemoglobin MCH) remained unchanged throughout the experiment for all the doses tested 5, 10, 20, and 40 (mg/L). According to the results of this study, exposure to CuO/ZnO core/shell NPs deteriorates the Triiodothyronine hormone (T3) and a Thyroxine hormone (T4) activated by Thyroid-Stimulating Hormone (TSH), which is generated and secreted from the pituitary gland. There is possibly related to an increase in free radicals and a decrease in antioxidant activity. Significant (p < 0.01) growth retardation in all groups treated due to rats' infection by Hyperthyroidism induced by thyroxine (T4) level increase. Hyperthyroidism is a catabolic state related to increased energy consumption, protein turnover, and lipolysis. Usually, these metabolic effects result in weight reduction and a decrease in fat storage and lean body mass. The histological examination indicates that the low concentrations of CuO/ZnO core/shell nanoparticles are safe for desired biomedical applications.

Argon inhalation attenuates systemic inflammation and rescues lung architecture during experimental neonatal sepsis.

PURPOSE: Neonatal sepsis is a systemic inflammatory infection common in premature infants and a leading cause of mortality. Argon is an emerging interest in the field of noble gas therapy. Neonates with severe sepsis are frequently mechanically ventilated creating an opportunity for inhalation therapy. We aimed to investigate argon inhalation as a novel experimental therapy in neonatal sepsis. METHODS: Sepsis was established in C57BL/6 neonatal mice by a lipopolysaccharide intraperitoneal injection on postnatal day 9. Septic pup mice were exposed to room air as well as non-septic controls. In the argon group, septic pup mice were exposed to argon (70% Ar, 30% O2) for 6 h in a temperature-controlled environment. RESULTS: At 6 h, survival was significantly enhanced when septic mice received argon compared to septic controls. Serum profiles of cytokine release were significantly attenuated as well as lung architecture restored. CONCLUSIONS: Our findings suggest that argon inhalation as a novel treatment for neonatal sepsis, reducing mortality and counteracting the acute systemic inflammatory response in the blood and preserving the architecture of the lung. This research can contribute to a paradigm shift in the treatment and outcome of neonates with sepsis.

UV Laser-Induced Phototransformations of Matrix-Isolated 5-Chloro-3-nitro-2-hydroxyacetophenone.

Conformational changes of 5-chloro-3-nitro-2-hydroxyacetophenone were studied by experimental and theoretical methods. Phototransformations of the compound were induced in low-temperature argon matrices by using UV radiation, which was followed by FT-IR measurements. Two types of changes within the molecule were detected: rotations of the hydroxyl and acetyl groups. A new conformer without an intramolecular hydrogen bond was generated upon irradiation with λ = 330 nm, whereas the reverse reaction was observed at 415 nm.

Insight into the Binding of Argon to Cyclic Water Clusters from Symmetry-Adapted Perturbation Theory.

This work systematically examines the interactions between a single argon atom and the edges and faces of cyclic H2O clusters containing three-five water molecules (Ar(H2O)n=3-5). Full geometry optimizations and subsequent harmonic vibrational frequency computations were performed using MP2 with a triple-ζ correlation consistent basis set augmented with diffuse functions on the heavy atoms (cc-pVTZ for H and aug-cc-pVTZ for O and Ar; denoted as haTZ). Optimized structures and harmonic vibrational frequencies were also obtained with the two-body-many-body (2b:Mb) and three-body-many-body (3b:Mb) techniques; here, high-level CCSD(T) computations capture up through the two-body or three-body contributions from the many-body expansion, respectively, while less demanding MP2 computations recover all higher-order contributions. Five unique stationary points have been identified in which Ar binds to the cyclic water trimer, along with four for (H2O)4 and three for (H2O)5. To the best of our knowledge, eleven of these twelve structures have been characterized here for the first time. Ar consistently binds more strongly to the faces than the edges of the cyclic (H2O)n clusters, by as much as a factor of two. The 3b:Mb electronic energies computed with the haTZ basis set indicate that Ar binds to the faces of the water clusters by at least 3 kJ mol-1 and by nearly 6 kJ mol-1 for one Ar(H2O)5 complex. An analysis of the interaction energies for the different binding motifs based on symmetry-adapted perturbation theory (SAPT) indicates that dispersion interactions are primarily responsible for the observed trends. The binding of a single Ar atom to a face of these cyclic water clusters can induce perturbations to the harmonic vibrational frequencies on the order of 5 cm-1 for some hydrogen-bonded OH stretching frequencies.

Effects of Argon Gas Plasma Treatment on Biocompatibility of Nanostructured Titanium.

In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site.

Experimental FTIR-MI and Theoretical Studies of Isocyanic Acid Aggregates.

Homoaggregates of isocyanic acid (HNCO) were studied using FTIR spectroscopy combined with a low-temperature matrix isolation technique and quantum chemical calculations. Computationally, the structures of the HNCO dimers and trimers were optimized at the MP2, B3LYPD3 and B2PLYPD3 levels of theory employing the 6-311++G(3df,3pd) basis set. Topological analysis of the electron density (AIM) was used to identify the type of non-covalent interactions in the studied aggregates. Five stable minima were located on the potential energy surface for (HNCO)2, and nine were located on the potential energy surface for (HNCO)3. The most stable dimer (D1) involves a weak, almost linear N-H⋯N hydrogen bond. Other structures are bound by a N-H⋯O hydrogen bond or by O⋯C or N⋯N van der Waals interactions. Similar types of interactions as in (HNCO)2 were found in the case of HNCO trimers. Among nine stable (HNCO)3 structures, five represent cyclic forms. The most stable T1 trimer structure is characterized by a six-membered ring formed by three N-H⋯N hydrogen bonds and representing high symmetry (C3h). The analysis of the HNCO/Ar spectra after deposition indicates that the N-H⋯O hydrogen-bonded dimers are especially prevalent. Upon annealing, HNCO trimers were observed as well. Identification of the experimentally observed species relied on previous experimental data on HNCO complexes as well as computed data on HNCO homoaggregates' vibrational spectra.