On the Use of the Fricke-Pluronic F-127 Gel Dosimeter for Radiation Isocenter Testing of a Medical Linear Accelerator.

This work presents a Fricke-XO-Pluronic F-127 2D radiochromic dosimeter with a flat-bed scanner for 2D reading and a dedicated data processing software package as a tool for performing coincidence testing of the radiation and mechanical isocenter of a medical accelerator. The optimal irradiation parameters were determined as follows: monitor units per beam and multi-leaf collimator gap, which are ≤750-≤2500 MU and 2-5 mm, respectively, for a cuboidal container with dimensions of 12 × 12 × 0.3 cm3. Despite the diffusion of Fe3+ ions occurring during irradiation, 2D reading can be performed at least 3 h after irradiation, without affecting the calculation performance of the coincidence test. The test was successfully performed for various irradiation settings. Overall, the Fricke-XO-Pluronic F-127 dosimeter has proven to be a potential tool for the coincidence testing of medical accelerators.

Effect of Testing Conditions on Low-Cycle Fatigue Durability of Pre-Strained S420M Steel Specimens.

S420M steel subjected to strain-controlled low-cycle fatigue does not exhibit a period of cyclic properties stabilization. The maximum stress on a cycle continuously drops until fracture. For this reason, it is difficult to plan experimental research for different types of control in such a way that their results can be considered comparable. The aim of this paper is to present and discuss the results of tests conducted in various conditions of low-cycle fatigue of S420M steel specimens, both undeformed and pre-strained. In both loading conditions, after initial deformation, a significant change in the cyclic properties of steel described by the parameters of the hysteresis loop was observed. Also, the fatigue life of the pre-strained specimens appeared to be different from unstrained specimens and was affected by the test loading conditions. The reduction in life under controlled stress conditions was attributed to the increase in the extent of plastic deformation and stress and the occurrence of creep.

Antimicrobial Effects of Some Natural Products on Adhesion and Biofilm Inhibition of Clostridioides difficile.

Understanding the potential antimicrobial properties of natural compounds and their impacts on Clostridioides difficile virulence factors may aid in developing alternative strategies for preventing and treating C. difficile infections (CDI). In this study, we investigated the bactericidal effects of ginger oil (GO), peppermint oil (PO), curcumin (CU), cinnamon aldehyde (CI), and trans-cinnamaldehyde (TCI) on the adhesion and biofilm disruption of C. difficile. We used three reference and five clinical C. difficile strains of different ribotypes. The bactericidal activity was assessed using the broth microdilution method. The adhesion was evaluated using human epithelial cell lines, and biofilm formation was visualized by confocal laser scanning microscopy. All tested strains exhibited susceptibility to CU, with minimum inhibitory concentration (MIC) values ranging from 128 µg/mL to 2048 µg/mL. Similarly, all strains were susceptible to CI and TCI, with MIC values ranging from 6.25% (v/v) to 25% (v/v). Most of the tested substances reduced the adhesion of C. difficile strains, while two tested strains showed significantly higher adhesion when co-incubated with the tested substances. Similar observations were made for biofilm formation, with observed density and morphology varied depending on the strain. In conclusion, the tested products demonstrated bactericidal activity and reduced the adhesion of C. difficile strains. They may be considered for further studies as potential antimicrobial agents targeting biofilm-related infections.

The Anterior Inferior Cerebral Artery Variability in the Context of Neurovascular Compression Syndromes: A Narrative Review.

The anterior inferior cerebellar artery (AICA) is situated within the posterior cranial fossa and typically arises from the basilar artery, usually at the pontomedullary junction. AICA is implicated in various clinical conditions, encompassing the development of aneurysms, thrombus formation, and the manifestation of lateral pontine syndrome. Furthermore, owing to its close proximity to cranial nerves within the middle cerebellopontine angle, AICA's pulsatile compression at the root entry/exit zone of cranial nerves may give rise to specific neurovascular compression syndromes (NVCs), including hemifacial spasm (HFS) and geniculate neuralgia concurrent with HFS. In this narrative review, we undertake an examination of the influence of anatomical variations in AICA on the occurrence of NVCs. Significant methodological disparities between cadaveric and radiological studies (CTA, MRA, and DSA) were found, particularly in diagnosing AICA's absence, which was more common in radiological studies (up to 36.1%) compared to cadaver studies (less than 5%). Other observed variations included atypical origins from the vertebral artery and basilar-vertebral junction, as well as the AICA-and-PICA common trunk. Single cases of arterial triplication or fenestration have also been documented. Specifically, in relation to HFS, AICA variants that compress the facial nerve at its root entry/exit zone include parabola-shaped loops, dominant segments proximal to the REZ, and anchor-shaped bifurcations impacting the nerve's cisternal portion.

The Effect of Subinhibitory Concentration of Metronidazole on the Growth and Biofilm Formation on Toxigenic Clostridioides difficile Strains Belonging to Different Ribotypes.

Clostridioides difficile is a predominant nosocomial pathogen within the healthcare setting able to produce biofilms. Sub-minimum inhibitory concentrations (sub-MICs) of antibiotics trigger mechanisms affecting bacterial virulence, including increased adhesion and biofilm formation. The aim of this study was to investigate how sub-MICs of metronidazole affect the biofilm formation of C. difficile strains. We tested 14 reference and clinical C. difficile strains, including hypervirulent strains of RT027. The MICs of metronidazole for the tested strains were determined using the broth microdilution method. Biofilm formation was evaluated using confocal laser scanning microscopy. The C. difficile strains belonging to RT027 produced the highest amounts of biofilm. The results of confocal laser scanning microscopy showed that all the tested C. difficile strains developed larger biofilms with diversified architectures upon exposure to sub-MICs of metronidazole. In our study, we reveal that sub-MIC concentrations of metronidazole affect the biofilm formation of clinical and reference strains of C. difficile. Importantly, metronidazole induces biofilm formation via hypervirulent RT027 strains.

The Superior Cerebellar Artery: Variability and Clinical Significance.

The superior cerebellar artery (SCA) arises from the distal part of the basilar artery and passes by the oculomotor, trochlear, and trigeminal nerves. SCA is known to play a crucial role in the development of trigeminal neuralgia. However, due to its anatomical variability, it may also trigger other neurovascular compression (NVC), including hemifacial spasm, oculomotor nerve palsy, and ocular neuromyotonia. Additionally, it may be associated with ischemic syndromes and aneurysm development, highlighting its clinical significance. The most common anatomical variations of the SCA include duplication, a single vessel origin from the posterior cerebral artery (PCA), and a common trunk with PCA. Rarely observed variants include bifurcation and origin from the internal carotid artery. Certain anatomical variants such as early bifurcation and caudal course of duplicated SCA trunk may increase the risk of NVC. In this narrative review, we aimed to examine the impact of the anatomical variations of SCA on the NVCs based on papers published in Pubmed, Scopus, and Web of Science databases with a snowballing approach. Our review emphasizes the importance of a thorough understanding of the anatomical variability of SCA to optimize the management of patients with NVCs associated with this artery.

Morphology and Anatomical Classification of Pericardial Cavities: Oblique and Transverse Sinuses.

The pericardial sinuses are an important anatomical feature of the pericardial cavity, however, their clinical anatomy has not been thoroughly studied. In this study, we aim to provide the first classification of the oblique and transverse sinuses. We analyzed 121 computer tomography scans (46.3% female, age of 66 ± 12 years) of the pericardial cavity. The oblique sinuses were classified into four types: 1 (shallow with narrow entrance), 2 (shallow with wide entrance), 3 (deep with narrow entrance), and 4 (deep with wide entrance). The transverse sinuses were classified into four types: Concave, Wine-type, Straight, and Convex. The most common oblique sinus type was Type 1. The median oblique sinus volume was 8.4 (5.3) mL, the median entrance length was 33.0 (13.2) mm, and the depth was 38.2 (11.8) mm. The most common transverse sinus type was Concave. The median transverse sinus volume was 14.8 (6.5) mL, and the median length was 52.8 (17.7) mm. Our study provides an anatomical classification of the pericardial sinuses. The individual variability of the sinuses' morphology highlights the importance of understanding the clinical topography of the sinuses, particularly for minimally invasive thoracic ablation procedures.

Influence of Pre-Strain on Static and Fatigue Properties of S420M Steel.

This paper reports the results of static tensile and low-cycle fatigue tests on S420M steel specimens. As-received (unstrained) and pre-strained specimens were used during the tests. Based on the static tensile tests carried out, no effect of pre-strain on the basic strength parameters of the S420M steel was found. Low-cycle fatigue tests showed that the pre-strain of the specimens causes a change in the cyclic properties of the steel and a slight increase in fatigue life compared to that of the as-received specimens. The greatest increase in durability was observed at the lowest strain levels.

Impact of Salt on Thermal Stability and Dose Response of the Fricke-XO-Pluronic F-127 3D Radiotherapy Dosimeter.

Fricke-XO-Pluronic F-127 has recently been proposed as a 3D dosimeter for radiotherapy. It contains the typical ingredients of the Fricke ionizing radiation dosimeter, which are embedded in a physical gel of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127). The main reactions upon irradiation are the conversion of Fe+2 to Fe+3 and the formation of a colored complex with XO ([XO-Fe]+3). The study attempts to optimize the dosimeter in terms of its solution-to-gel transition temperature. In order to lower this temperature, the use of NaCl salt has been proposed. The new composition was characterized in order to obtain information on its thermal performance, storage stability, dose response to irradiation with a medical accelerator emitting different types of radiation, and tissue equivalence. The results obtained show an improvement in the sol-gel transition temperature and dose sensitivity compared to the composition without NaCl and broaden the knowledge of the Fricke-XO-Pluronic F-127.

Validation of the Elderly Traumatic Brain Injury Score: Observational Case Control Study.

BACKGROUND: Traumatic brain injury (TBI) poses a particular health risk for the elderly. The recently developed elderly TBI (eTBI) score combines the prognostic information of the risk factors characteristic of the geriatric population. We aimed to determine its validity and reliability on an independent sample. METHODS: We present a retrospective analysis of 506 consecutive patients after TBI aged ≥65 years. The previously described nomogram and the eTBI score were used. The primary outcome measure was mortality or vegetative state at 30 days after hospital admission. RESULTS: Mortality or vegetative state rate was 21.3%. The nomogram and eTBI Score showed similar predictive performance with accuracy of 83.8% (95% confidence interval 80.2%-87%) and 84.4% (95% confidence interval 80.8%-87.6%), respectively. On the basis of the Youden index and C4.5 algorithm, we divided patients according to the 3-tier pattern into low-, high-, and medium-risk groups. The outcome prediction in the first 2 groups was correct in 93.1% (survival in the low-risk group) and 94.4% (mortality in the high-risk group). Patients included in the medium-risk group usually required surgical treatment (85.3%) and were characterized by increased mortality or vegetative state (55%). Among patients with eTBI ≥5 (n = 221), there was no difference in outcome between those treated conservatively and surgically. CONCLUSIONS: This is the first study confirming the validity of the eTBI Score and its close association with outcome of geriatric population after TBI. The novel 3-tier risk stratification scheme was applicable to both conservatively and surgically treated patients.

Effect of prebiotics on Bacteroides sp. adhesion and biofilm formation and synbiotic effect on Clostridioides difficile.

Aim: The objective of this study was to determine the effect of standard and candidate prebiotics on the adhesion and biofilm formation of Bacteroides sp. in monoculture and co-culture with Clostridioides difficile. Materials & methods: The effect of seven prebiotics on the adhesion and biofilm formation of Bacteroides sp. to three human cell lines was determined. The effect of Bacteroides sp. and fructooligosaccharides (FOS) on the adhesion and biofilm formation of C. difficile was tested by the co-incubation assay. Results: Inulin, mannose and raffinose presented the best anti-adhesion properties against Bacteroides sp. Combination of Bacteroides sp. with FOS decreased the adhesion of C. difficile. Conclusion: The study shows the potential role of prebiotics and synbiotics in decreasing the burden of C. difficile infections.

Study of the Optimal Composition and Storage Conditions of the Fricke-XO-Pluronic F-127 Radiochromic Dosimeter.

This paper presents the results of research on the Fricke-XO-Pluronic F-127 dosimeter. It consists of a Fricke dosimetric solution and xylenol orange (XO), which are embedded in a matrix of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127). Upon irradiation, Fe+2 ions transform into Fe+3, forming a colored complex with XO ([XO-Fe]+3). The color intensity is related to the dose absorbed. The optimal composition, storage conditions, and radiation-induced performance of the Fricke-XO-Pluronic F-127 dosimeter were investigated. The optimal composition was found to be 1 mM FAS, 50 mM sulfuric acid (H2SO4), 0.165 mM XO in 25% Pluronic F-127. The basic features of this dosimeter are discussed, such as dose sensitivity, linear and dynamic dose range, stability before and after irradiation, storage conditions, dose response for irradiation with 6 and 15 MV photons, and batch-to-batch reproducibility. The obtained results showed a certain potential of the Fricke-XO-Pluronic F-127 for radiotherapy dosimetry.

Plasma Amino Acids May Improve Prediction Accuracy of Cerebral Vasospasm after Aneurysmal Subarachnoid Haemorrhage.

Aneurysmal subarachnoid haemorrhages (aSAH) account for 5% of strokes and continues to place a great burden on patients and their families. Cerebral vasospasm (CVS) is one of the main causes of death after aSAH, and is usually diagnosed between day 3 and 14 after bleeding. Its pathogenesis remains poorly understood. To verify whether plasma concentration of amino acids have prognostic value in predicting CVS, we analysed data from 35 patients after aSAH (median age 55 years, IQR 39-62; 20 females, 57.1%), and 37 healthy volunteers (median age 50 years, IQR 38-56; 19 females, 51.4%). Fasting peripheral blood samples were collected on postoperative day one and seven. High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis was performed. The results showed that plasma from patients after aSAH featured a distinctive amino acids concentration which was presented in both principal component analysis and direct comparison. No significant differences were noted between postoperative day one and seven. A total of 18 patients from the study group (51.4%) developed CVS. Hydroxyproline (AUC = 0.7042, 95%CI 0.5259-0.8826, p = 0.0248) and phenylalanine (AUC = 0.6944, 95%CI 0.5119-0.877, p = 0.0368) presented significant CVS prediction potential. Combining the Hunt-Hess Scale and plasma levels of hydroxyproline and phenylalanine provided the model with the best predictive performance and the lowest leave-one-out cross-validation of performance error. Our results suggest that plasma amino acids may improve sensitivity and specificity of Hunt-Hess scale in predicting CVS.

Motility and the genotype diversity of the flagellin genes fliC and fliD among Clostridioides difficile ribotypes.

OBJECTIVE: The motility and genotype of the flagellin fliC and fliD genes were investigated in 82 Clostridioides difficile isolates belonging to the ribotypes (RTs): 027 (n = 41), 176 (n = 17), 023 (n = 8), 017 (n = 6) and 046 (n = 10). The reference C. difficile strains 630 and M120 were included as controls for the motility assay. METHODS: A Multiple Locus Variable-number Tandem Repeat Analysis (MLVA) was used to exclude the genetic relatedness of C. difficile isolates belonging to the same RT. The variability of the fliC and fliD genes was determined by PCR-restriction fragment length polymorphism (RFLP) analysis and Sanger sequencing. The motility assay was carried out with 0.175% BHI agar tubes and BHI solid media plates with 0.4% agar. RESULTS: The highest motility was observed in C. difficile RT023 isolates (p < 0.01), followed by RTs 027 and 176. C. difficile isolates of RTs 017 and 046 were less motile than RTs 027, 176 and 023 (p < 0.01). The fliC and fliD genes were present in all clinical isolates irrespective of the motility results. In the fliC gene analysis, four different RFLP groups were identified (I, II, VII, X). The fliC group VII was identified in two RTs (027 and 176), whereas the remaining three groups (I, II and X) belonged to a single RT 046, 017 and 023, respectively. The fliD gene analysis identified four new RFLP groups (a, b, c and d). CONCLUSIONS: C. difficile RT023 is highly motile and its motility is comparable to the hypervirulent RT027 and its genetic relative RT176.

The prebiotic effect of human milk oligosaccharides 3'- and 6'-sialyllactose on adhesion and biofilm formation by Clostridioides difficile - pilot study.

Bacterial adhesion is the first stage of colonisation and biofilm formation by Clostridioides difficile. Cell wall proteins (Cwp) 84 and 66 play crucial roles in the pathophysiology of C. difficile and may affect bacterial adhesion. Sialylated human milk oligosaccharides (HMOs) have potential to inhibit bacterial adhesion in vitro. The aim of this study was to investigate how 3'-sialyllactose (SL) and 6'-SL affect adhesion and C. difficile biofilm formation. Also, the influence of these substances on cwp84 and cwp66 genes expression by C. difficile was assessed. An adhesion assay was performed using three human colon cells in vitro, and biofilm formation was evaluated using crystal violet staining and confocal laser scanning microscopy. The effect of 3'-SL and 6'SL on cwp expression was measured using real time-PCR. Both tested HMOs decreased expression of the cwp84 gene, adhesion of C. difficile to human colon cells in vitro and biofilm formation.

Concentration of 7Be, 210Pb, 40K, 137Cs, 134Cs radionuclides in the ground layer of the atmosphere in the polar (Hornsund, Spitsbergen) and mid-latitudes (Otwock-Swider, Poland) regions.

This paper presents results of measurements of selected gamma-radioactive radionuclide concentrations (7Be, 210Pb, 40K, 137Cs, 134Cs) in atmospheric aerosols registered in 2002-2017 at the Polish Polar Station of the Institute of Geophysics Polish Academy of Science in Hornsund and in the S. Kalinowski's Geophysical Observatory Institute of Geophysics Polish Academy of Science in Swider. The above measurements and tests are used to control and track long-term concentrations of radionuclides depending on the geometeorological conditions prevailing in the vicinity of the station. Collecting radiological data from polar regions and comparing them with data from medium latitudes leads to a better understanding of the mechanisms of creation and propagation of radionuclides in the air. Hornsund station is one of the northernmost measuring site for continuous airborne radionuclide monitoring in the Spitsbergen archipelago. It also allows the analysis of the relationship of radionuclides to the Earth's magnetic field.

Experimental and numerical modeling approach for thermomechanical low cycle fatigue analysis of cyclically non-stabilized steels.

The widely used fatigue life prediction models, such as the Coffin-Manson model or S-N curve related models are based on the assumption that the response of a material experiencing low cycle fatigue loading is stabilized during some period. However, for many materials such a stabilized state is hardly observed, and the activated mechanisms for cyclic hardening or softening depend on test conditions. In general, the selected test conditions (stress or strain control) should depend on the intended use of the obtained material data. If testing conditions do not correspond to the operation mode of the considered mechanical facilities, the above mentioned life prediction models will produce inaccurate results. Hence, selecting and identifying proper fatigue parameters, which would represent the state of a material during the whole fatigue life, is extremely important in reliability evaluation of structures. In the case of non-stabilizing steels, the common challenges are:•Selecting and performing a suitable set of experimental tests to recognize various aspects of the material behavior under low-cycle thermomechanical fatigue;•Adjusting a proper constitutive modelling, reflecting the real physical phenomena taking place in the material microstructure;•Effective numerical implementation and optimal parameter identification.

Atypical and rare cause of myocardial infarction: coronary subclavian steal syndrome (CSSS) treated by a carotid-subclavian bypass in a 71-year-old female patient.

BACKGROUND: The coronary subclavian steal syndrome (CSSS) is a rare complication after coronary arterial bypass graft operations (CABG) using the left or right internal mammary artery ((L/R)IMA). It results from a retrograde blood flow from the IMA into the subclavian artery (SA) due to a stenosis or occlusion of the SA proximal to the IMA origin. This "steal phenomenon" leads to a decreased blood flow in the IMA and may result in myocardial ischemia (MIS) and even myocardial infarction (MIN). Treatment options include interventional and surgical therapy. CASE PRESENTATION: We report the case of a 71-year old woman, who suffered from an acute non-ST elevation myocardial infarction (NSTEMI) 11 years after LIMA-CABG surgery and who was treated successfully with a carotid-subclavian bypass (CSB) after failed interventional therapy. CONCLUSION: CSB may be regarded as a viable treatment option for patients suffering CSSS in the case of MIS and even an acute MIN/NSTEMI, especially in the case of missing or failed interventional therapy attempts. Specialists in cardiothoracic and vascular surgery should be aware of possible CSSS conditions and know about appropriate diagnostic and therapeutic options.

Ruthenium as an important element in nuclear energy and cancer treatment.

Ruthenium belongs to the platinum group metals (PGMs) which include palladium (Pd), platinum (Pt), osmium (Os), iridium (Ir) and rhodium (Rh). Radioactive isotopes of ruthenium are important elements related to the nuclear field. Ruthenium is one of the fission products in nuclear reactors and one of the troublesome nuclide in reprocessing process of the spent nuclear fuel (PUREX). The increased concentration of ruthenium-106 in the environment can be the result of accidents in nuclear power plants, spent nuclear fuel processing plants, or of nuclear tests. On the other hand, radioisotope of ruthenium Ru-106 is a drug that is successfully used in brachytherapy. In this paper we describe both sides of this element.

The effect of berberine chloride and/or its combination with vancomycin on the growth, biofilm formation, and motility of Clostridioides difficile.

This study aims to investigate the antimicrobial and antibiofilm activity of berberine chloride (BBR) and vancomycin (VAN) as well as synergistic combinations of BBR with VAN against Clostridioides difficile strains. The effect of different concentrations of BBR on strain motility was also assessed. Twelve C. difficile strains (two reference C. difficile 630, ATCC 9689, and one control M120, and 9 clinical C. difficile strains belonging to the PCR-ribotype (RT027)) were collected and investigated for their susceptibility to BBR and VAN in planktonic and biofilm forms. Both the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of BBR for the C. difficile strains were found to vary over a broad range (256-1.024 mg/L and 256-16.384 mg/L, respectively). The MIC and MBC of VAN also varied greatly, ranging from 0.25 to 4.0 mg/L for MIC and 0.25 to 64.0 mg/L for MBC. The synergistic effect of the sub-MIC (1/2 MIC) BBR with VAN reduced of MICs of VAN against the planktonic forms of ten C. difficile strains. The sub-MIC of BBR enhanced the biofilm formation of one strain and was found to be statistically significant. In addition, the sub-MIC of BBR with VAN surprisingly enhanced the biofilm formation of one C. difficile strain. The effect of inhibition of motility in the presence of BBR was statistically significant for 3 clinical strains (p < 0.05). Altogether, BBR exhibited strong antimicrobial activity against C. difficile, and the analysis of the combination of BBR with VAN showed a synergistic effect.