2-D nanometer thickness mapping applying a reduced bias soft X-ray NEXAFS approach

We present a 2-D mapping of a sample thickness with nanometer accuracy employing a compact arrangement of near-edge X-ray absorption fine structure (NEXAFS) technique. A NEXAFS spectrum coupled with a scanning system was used to generate a 2-D thickness map of the TiO₂ sample (anatase form) deposited on the top of a SiN membrane. The thickness values were retrieved from the experimental data by applying different methods of data processing. In the paper, the detailed analysis of the data processing methods and the identified sources of the errors show that the proposed procedure based on averaging two imperfect estimates reduces the error caused by the uncontrolled bias of the measured signals. This procedure was termed as the average one. The estimates from the proposed average approach and the standard absorption-jump ratio in the absorption edge vicinity were compared with the direct results obtained by applying scanning electron microscopy (SEM). The experimental arrangement of the NEXAFS spectroscopy system, the data acquisition method, as well as the possible error sources, are presented and discussed in detail.

A comparison of the remineralizing potential of dental restorative materials by analyzing their fluoride release profiles

BACKGROUND

The accessibility of the remineralizing ions in teeth's environment is essential for their incorporation into caries-affected dentin. Novel bioglass-reinforced materials capable of releasing fluoride, calcium and phosphates may be particularly useful in the tissue remineralization process. A novel restorative material, ACTIVA BioActive-Restorative (Pulpdent Corp., Watertown, USA), is a hydrophilic resin-modified glassionomer cement (RMGIC) enriched with bioglass particles and fortified with a patented rubberized polymer resin. Its application in restorative dentistry may be significant, promoting remineralization of carious lesions.

OBJECTIVES

The aim of the study was to compare the fluoride ion release profiles from a bioglass-reinforced RMGIC, a conventional glass-ionomer cement (GIC) and a nanohybrid restorative polymer resin.

MATERIAL AND METHODS

The quantity of fluoride ions released from ACTIVA, Ketac Molar Quick Aplicap and Tetric EvoCeram was assessed using a fluoride-specific electrode. The surface characteristics of the preand post-experimental specimens were studied using a scanning electron microscope (SEM) and confocal microscope. An X-ray powder diffraction (XRD) analysis was additionally used to examine the chemical compositions of the dental materials.

RESULTS

The greatest quantity of fluoride ions was freed from the GIC specimens (20.698-54.118 ppm), followed by the bioglass-reinforced RMGIC (from 1.236 to 15.552 ppm) and nanohybrid polymer resin (0.370-1.148 ppm). The pre-experimental specimens of the bioglass-reinforced RMGIC were porous, while the post-experimental specimens were smoother with visible micro-cracks. The XRD analysis of the bioglass particles confirmed that the material was composed mainly of fluoride (27.70 mass%), silicon (15.62 mass%), aluminum (5.91 mass%), and calcium (5.40 mass%).

CONCLUSIONS

The fluoride ion release profile of ACTIVA was lower than the GIC Keta Molar Quick Aplicap, but significantly higher than the nanohybrid restorative polymer resin Tetric EvoCeram.

Haemodynamic changes of the deep vein system of the leg after surgery of the incompetent great saphenous vein

Surgical treatment of chronic venous disease primarily aims to restore the normal haemodynamic conditions in the venous system. The objective of the study was an assessment of the influence of incompetent saphenous vein removal on the haemodynamical changes within the venous and arterial system of the operated extremity. Patients, materials, methods: The study utilised a group of 50 patients presenting with varicose veins (C2 according to CEAP classification) and great saphenous vein incompetence selected for saphenous vein stripping. In all patients, duplex Doppler examination of femoral and popliteal veins as well as femoral and popliteal arteries was performed before surgery, on the first postoperative day and 30 days after surgery. Results: After the removal of an incompetent great saphenous vein, a statistically significant increase in the minute volume flow in the femoral (p = 0.0004) and popliteal veins (p = 0.0011) was observed. Following saphenous vein stripping, a statistically significant reduction of the venous reflux time in the deep vein system was also observed in the common femoral, femoral and popliteal veins, as compared to a pre-operative examination. Postoperatively, normalisation of the venous reflux time was achieved in 36–40% of patients from the group with concomitant deep vein system incompetence. As far as the arterial system is concerned, an increase in the volume flow in the femoral (p = 0.0463) and popliteal arteries was observed, but statistical significance was not achieved in the latter (p = 0.2912). Conclusion: The flow in the deep vein system increases after the removal of the incompetent great saphenous vein. In some patients with an incompetent deep vein system, venous reflux time returns to normal after the incompetent saphenous vein has been removed.

Decreased Frequencies of Peripheral Blood CD4+CD25+CD127-Foxp3+ in Patients with Graves' Disease and Graves' Orbitopathy: Enhancing Effect of Insulin Growth Factor-1 on Treg Cells

Graves' orbitopathy (GO) is characterized by orbital T cell infiltration. We evaluated the regulatory T (Treg) cell fractions induced with IGF-1 in Graves' disease (GD) with and without GO. Peripheral blood mononuclear cells (PBMCs) were obtained from 13 patients with GD without eye manifestations; 10 patients with active GO; and 12 patients with nodular goiter (NG). All the patients from GD, GO, and NG were subclinical hyperthyroid. We analyzed the expression of Treg cell markers (CD4, CD25, CD127^-, Foxp3) on T cells and their ability to respond to IGF-1 stimulation. In patients with GD without GO, we found lowered percentages of CD4⁺ Foxp3⁺ cells, as compared to nodular goiter 1.77 vs. 5.42% (p=0.0276). Similarly, significantly reduced frequencies of CD4⁺CD25⁺CD127^-Foxp3⁺ and CD4⁺CD25⁺CD127^- cells were observed in GD patients as compared to nodular goiter patients with hyperthyreosis, (0.7 vs. 1.48%) (p=0.0071) and (14.5 vs. 37.2%) (p=0.0051), respectively. In GO with active GO, only the percentage of CD4⁺CD25⁺CD127^- cells was found to be decreased versus nodular goiter (9.35 vs. 37.2) (p=0.0275). Stimulation of PBMC derived from GO patients with IGF-1 resulted in significant increase of frequency of both CD4⁺ Foxp3⁺ and CD4⁺CD25⁺CD127^- Foxp3 cells. Decreased frequencies of peripheral blood CD4⁺CD25⁺CD127^-Foxp3⁺ in patients with GD and GO could be an useful marker of autoimmune process and perhaps a possible target for future therapies. This is the first study demonstrating Treg-enhancing effects of IGF-1. Thus IGF-1 can be accounted for modulating Treg cell-related action in GO.

Single, very low dose (0.03 mg) of recombinant human thyrotropin (rhTSH) effectively increases radioiodine uptake in the I-131 treatment of large nontoxic multinodular goiter

BACKGROUND

Radioiodine therapy (RIT) in patients with large nontoxic multinodular goiter (MNG) recently becomes more common method in comparison to surgery (especially in elderly patients and with contraindications because of severe chronic diseases other systems). Repeatedly low thyroid radioactive iodine uptake (RAIU) decreases effectiveness of RIT or makes it impossible. The recombinant human thyrotropin can increase RAIU and improve the results of RIT.

THE AIM OF THE STUDY

was to assess the influence of a single very low dose (0.03 mg) of rhTSH on RAIU and thyroid function in euthyroid (MNG-EU) and subclinical hyperthyroid (MNG-SC) patients with a large multinodular goiter.

MATERIAL AND METHODS

40 patients (14 male, 26 female, age 57-80 yr) with large non-toxic MNG over 80 grams and with baseline RAIU < 40% were included into the double-blind randomized study and divided into two groups: rhTSH-group and control group. First group received the single intramuscular injection of 0.03 mg rhTSH and the second received placebo. The RAIU were measured 24 and 48 hours after the rhTSH and then all the patients were administered therapeutic doses of I-131. TSH and free thyroxine levels were measured at 1st and 2nd day after the injection of rhTSH and later, at 4 and 8 weeks after the RIT.

RESULTS

The mean RAIU increased significantly from 30.44 ± 7.4% to 77.22 ± 8.7% (p < 0.001). There were no statistically significant differences in RAIU between euthyroid (MNG-EU) and subclinically hyperthyroid (MNG-SC) patients. The peak of serum TSH was noticed 24 hours after rhTSH injection and in MNG-EU patients it has remained within normal range, similarly as fT4. In the MNG-SC group the administration of rhTSH resulted in a significant increase in the TSH values after 24 hours, whose mean level slightly exceeded the upper limit of the normal range with normalization at 48 hours. 8 weeks after the RIT, the TSH and fT4 levels did not exceed the normal range and did not differ in a statistically significant way.

CONCLUSIONS

Even the single very low dose of rhTSH increases the values of RAIU in significant way, in euthyroid and subclinically hyperthyroid patients. The administration of rhTSH is well-tolerated. Neoadjuvant administration of a low dose (0.03 mg) of rhTSH before I-131 seems to be an optimal method of management which may increase the effectiveness of RIT and decrease the exposure of the patients to absorbed doses of ionizing radiation.

Extreme ultraviolet tomography using a compact laser-plasma source for 3D reconstruction of low density objects

A tomographic method for three-dimensional reconstruction of low density objects is presented and discussed. The experiment was performed in the extreme ultraviolet (EUV) spectral region using a desktop system for enhanced optical contrast and employing a compact laser-plasma EUV source, based on a double stream gas puff target. The system allows for volume reconstruction of transient gaseous objects, in this case gas jets, providing additional information for further characterization and optimization. Experimental details and reconstruction results are shown.

Surface modification of polymers for biocompatibility via exposure to extreme ultraviolet radiation

Polymeric biomaterials are being widely used for the treatment of various traumata, diseases and defects in human beings due to ease in their synthesis. As biomaterials have direct interaction with the extracellular environment in the biological world, biocompatibility is a topic of great significance. The introduction or enhancement of biocompatibility in certain polymers is still a challenge to overcome. Polymer biocompatibility can be controlled by surface modification. Various physical and chemical methods (e.g., chemical and plasma treatment, ion implantation, and ultraviolet irradiation etc.) are in use or being developed for the modification of polymer surfaces. However an important limitation in their employment is the alteration of bulk material. Different surface and bulk properties of biomaterials are often desirable for biomedical applications. Because extreme ultraviolet (EUV) radiation penetration is quite limited even in low density mediums, it could be possible to use it for surface modification without influencing the bulk material. This article reviews the degree of biocompatibility of different polymeric biomaterials being currently employed in various biomedical applications, the surface properties required to be modified for biocompatibility control, plasma and laser ablation based surface modification techniques, and research studies indicating possible use of EUV for enhancing biocompatibility.

Neck duplex Doppler ultrasound evaluation for assessing chronic cerebrospinal venous insufficiency in multiple sclerosis patients

INTRODUCTION

Recent clinical studies have suggested a relationship between multiple sclerosis (MS) and the occurrence of pathological changes in the jugular, vertebral and azygous veins that result in abnormal blood outflow from the brain and the spinal cord. Together, these pathological changes have been designated chronic cerebrospinal venous insufficiency (CCSVI). The aim of the present study was to evaluate the usefulness of duplex Doppler ultrasound in the evaluation of central nervous system venous outflow disturbances in patients suffering from MS.

METHODS

We examined 181 patients with MS, diagnosed on the basis of the McDonald criteria, and 50 healthy volunteer controls. All patients underwent Doppler ultrasound examination of the internal jugular veins (IJV) and vertebral veins (VVs). The presence of outflow disturbances and morphological abnormalities were evaluated.

RESULTS

Pathological changes in the extracranial jugular veins were diagnosed in 148/181 MS patients (82%) and 7/50 control group volunteers (14%). The following abnormalities in the MS group were revealed: the presence of a reflux in the IJVs and/or VVs (54%), narrowing (54%), a complete block in the flow through the IJV (10%) and an abnormal postural control of the cerebral outflow route (25%). These particular pathologies were of statistical significance in the MS group compared with the control group. This study also revealed a correlation between the occurrence of inverted flow in patients in a sitting position and chronic progressive MS (P = 0.0033).

CONCLUSIONS

The examinations undertaken indicate a possible connection between MS and CCSVI. The widely accessible and highly sensitive and specific Doppler ultrasound test may be useful for revealing, and preliminary analysis of, CCSVI pathologies.

A 50 nm spatial resolution EUV imaging-resolution dependence on object thickness and illumination bandwidth

In this paper we report a desk-top microscopy reaching 50 nm spatial resolution in very compact setup using a gas-puff laser plasma EUV source. The thickness of an object and the bandwidth of illuminating radiation were studied in order to estimate their quantitative influence on the EUV microscope spatial resolution. EUV images of various thickness objects obtained by illumination with variable bandwidth EUV radiation were compared in terms of knife-edge spatial resolution to study the bandwidth/object thickness parasitic influence on spatial resolution of the EUV microscope.

Extracranial Doppler sonographic criteria of chronic cerebrospinal venous insufficiency in the patients with multiple sclerosis

AIM

The aim of this open-label study was to assess extracranial Doppler criteria of chronic cerebrospinal venous insufficiency in multiple sclerosis patients.

METHODS

Seventy patients were assessed: 49 with relapsing-remitting, 5 with primary progressive and 16 with secondary progressive multiple sclerosis. The patients were aged 15-58 years and they suffered from multiple sclerosis for 0.5-40 years. Sonographic signs of abnormal venous outflow were detected in 64 patients (91.4%).

RESULTS

We found at least two of four extracranial criteria in 63 patients (90.0%), confirming that multiple sclerosis is stronghly associated with chronic cerebrospinal venous insufficiency. Additional transcranial investigations may increase the rate of patients found positive in our survey. Reflux in internal jugular and/or vertebral veins was present in 31 cases (42.8%), stenosis of internal jugular veins in 61 cases (87.1%), not detectable flow in internal jugular and/or vertebral veins in 37 cases (52.9%) and negative difference in cross-sectional area of the internal jugular vein assessed in the supine vs. sitting position in 28 cases (40.0%). Flow abnormalities in the vertebral veins were found in 8 patients (11.4%). Pathologic structures (membranaceous or netlike septa, or inverted valves) in the junction of internal jugular vein with brachiocephalic vein were found in 41 patients (58.6%), in 15 patients (21.4%) on one side only and in 26 patients (37.1%) bilaterally.

CONCLUSION

Multiple sclerosis is highly correlated with chronic cerebrospinal venous insufficiency. These abnormalities in the extracranial veins draining the central nervous system can exist in various combinations. The most common pathology in our patients was the presence of an inverted valve or another pathologic structure (like membranaceous or netlike septum) in the area of junction of the IJV with the brachiocephalic vein.

Congenital vena cava inferior agenesis

A patient aged 25 years with lower extremity deep vein thrombosis in the course of vena cava inferior agenesis is described. This very rare malformation can be connected with chronic venous insufficiency or thrombotic complications. In such cases other congenital abnormalities should be excluded and suspicion of vena cava inferior agenesis should always be taken into consideration in young patients with idiopathic deep vein thrombosis.