Long-term ice mass changes in Greenland and Antarctica derived from satellite laser ranging

Time-variable gravity field models obtained from satellite gravimetric techniques allow for the assessment of ice sheet mass changes in remote polar regions, such as Greenland and Antarctica. So far, GRACE has been the primary mission for obtaining the global time-variable gravity field models. However, GRACE was launched in 2002, thus very little is known about the global mass changes before this data, as well as between GRACE and its successor – GRACE Follow-On. We derive a method of gravity field recovery based on Satellite Laser Ranging (SLR) data to geodetic satellites that allows for obtaining direct ice mass change estimates for a period longer by 10 years than that provided by the GRACE missions. The developed method is based on splitting normal equation systems and re-stacking the solutions which allow for stable inversion, reduces the correlations between obtained parameters, stabilizes the ice mass estimates in polar regions, and reduces the noise over oceans by a factor of four. The secular trends obtained from SLR are equal to −113.5 and −82.8 Gt/year, whereas these are −119.1 and −83.3 Gt/year from GRACE and GRACE-FO to degree and order 10 for Greenland and West Antarctica, respectively, for the common period of 2002–2021 and after removing the post-glacial rebound effect. Despite the conformity of the trend and patterns, an underestimation is observed in the solutions expanded to degree and order 10. Therefore, scaling factors between GRACE/GRACE-FO expanded up to a degree and order 10 × 10 and 60 × 60 were derived and applied to SLR solutions to account for the differences in mass estimates due to the truncation of the models. SLR data revealed that in Greenland the smallest ice mass trends are for 1995–2000, 2000–2005, and 2015–2020 which are equal to +54.3, −15.5, and −75.9 Gt/year. The largest ice mass depletion periods took place in 2005–2010, 2010–2015, and recently in 2019–2021 with trends of −213.9, −287.2, and −276.1 Gt/year, respectively. For Greenland and West Antarctica, the period 2010–2015 is characterized by the most enormous ice depletion events, whereas the later 5-year period of 2015–2020 provided a near mass-equilibrium for Antarctica reducing the negative trend and returning to the situation from the ‘90s when no significant ice mass changes were observed

Satellite laser ranging to GNSS-based Swarm orbits with handling of systematic errors

Satellite laser ranging (SLR) retroreflectors along with GNSS receivers are installed onboard numerous active low earth orbiters (LEOs) for the independent validation of GNSS-based precise orbit determination (POD) products. SLR validation results still contain many systematic errors that require special handling of various biases. For this purpose, we derive methods of reducing systematic effects affecting the SLR residuals to LEO Swarm satellites. We test solutions incorporating the estimation of range biases, station coordinate corrections, tropospheric biases, and horizontal gradients of the troposphere delays. When estimating range biases once per day, the standard deviation (STD) of Swarm-B SLR residuals is reduced from 10 to 8 mm for the group of high-performing SLR stations. The tropospheric biases estimated once per day, instead of range biases, further reduce the STD of residuals to the level of 6 mm. The systematic errors that manifest as dependencies of SLR residuals under different measurement conditions, e.g., elevation angle, are remarkably diminished. Furthermore, introducing troposphere biases allows for the comparison of the orbit quality between kinematic and reduced-dynamic orbits as the GPS-based orbit errors become more pronounced when SLR observations are freed from elevation-dependent errors. Applying tropospheric biases in SLR allows obtaining the consistency between the POD solution and SLR observations that are two times better than when neglecting to model of systematic effects and by 29% better when compared with solutions considering present methods of range bias handling

Custom-Made Zirconium Dioxide Implants for Craniofacial Bone Reconstruction

Reconstruction of the facial skeleton is challenging for surgeons because of difficulties in proper shape restoration and maintenance of the proper long-term effect. ZrO2 implant application can be a solution with many advantages (e.g., osseointegration, stability, and radio-opaqueness) and lacks the disadvantages of other biomaterials (e.g., metalosis, radiotransparency, and no osseointegration) or autologous bone (e.g., morbidity, resorption, and low accuracy). We aimed to evaluate the possibility of using ZrO2 implants as a new application of this material for craniofacial bone defect reconstruction. First, osteoblast (skeleton-related cell) cytotoxicity and genotoxicity were determined in vitro by comparing ZrO2 implants and alumina particle air-abraded ZrO2 implants to the following: 1. a titanium alloy (standard material); 2. ultrahigh-molecular-weight polyethylene (a modern material used in orbital surgery); 3. a negative control (minimally cytotoxic or genotoxic agent action); 4. a positive control (maximally cytotoxic or genotoxic agent action). Next, 14 custom in vivo clinical ZrO2 implants were manufactured for post-traumatologic periorbital region reconstruction. The soft tissue position improvement in photogrammetry was recorded, and clinical follow-up was conducted at least 6 years postoperatively. All the investigated materials revealed no cytotoxicity. Alumina particle air-abraded ZrO2 implants showed genotoxicity compared to those without subjection to air abrasion ZrO2, which were not genotoxic. The 6-month and 6- to 8-year clinical results were aesthetic and stable. Skeleton reconstructions using osseointegrated, radio-opaque, personalized implants comprising ZrO2 material are the next option for craniofacial surgery

Renal artery sympathetic nerve radiofrequency denervation

Background: Arterial hypertension is one of the most common chronic diseases in the western world, affecting more than 25% of the adult population. Aim: The aim of this study was to assess changes in arterial blood pressure (BP) levels in hypertensive patients, after ablation of nerve terminals in renal arteries, using radiofrequency energy during 24 months of follow-up. Methods: Thirty-two patients with diagnosed resistant hypertension (20 men and 12 women) underwent percutaneous catheter-based renal denervation of nerve terminals in renal artery walls. Mean BP value before ablation was [mm Hg]: systolic 174.92, diastolic 99.73 and pulse pressure 75.19. After procedure reduction value of BP was reported [mm Hg]: systolic 146.78; diastolic 87.14, pulse pressure 59.64 at 24-month follow-up (p < 0.05 for all). Results: 30% of patients had systolic BP ≤ 140 mm Hg, 67% had diastolic BP ≤ 90 mm Hg, and optimum BP values ≤ 140/90 mm Hg were observed in 30% of patients. Conclusions: In our cohort of patients, percutaneous renal artery ablation procedure effectively reduces systolic, diastolic BP and pulse pressure. No adverse events during 24 months of follow-up were noted. These results were comparable with available data from SIMPLICITY I and II trials.Wstęp: Nadciśnienie tętnicze jest jedną z najbardziej powszechnych chorób przewlekłych w krajach zachodnich i dotyczy więcej niż 25% dorosłej populacji. Cel: Celem pracy była ocena zmian ciśnienia tętniczego (BP) u pacjentów z nadciśnieniem tętniczym po ablacji zakończeń nerwowych w tętnicach nerkowych z zastosowaniem prądu o wysokiej częstotliwości w 24-miesięcznej obserwacji. Metody: Trzydziestu dwóch pacjentów z rozpoznanym nadciśnieniem opornym (20 mężczyzn i 12 kobiet) poddano przezskórnej denerwacji zakończeń nerwowych w ścianie tętnic nerkowych. Średnia wartość ciśnienia krwi przed ablacją wynosiła [mm Hg]: 174,92 (skurczowe), 99,73 (rozkurczowe), a ciśnienie tętna — 75,19. Po 24 miesiącach obserwacji stwierdzono zmniejszenie wartości ciśnienia tętniczego [mm Hg]: skurczowe — 146,78; rozkurczowe — 87,14, ciśnienie tętna — 59,64. Wyniki: Wszystkie wyniki były statystycznie znamienne. U 30% pacjentów zanotowano wartość skurczowego BP ≤ 140 mm Hg, u 67% osób rozkurczowe BP wynosiło ≤ 90 mm Hg, natomiast optymalne wartości ciśnienia krwi (≤ 140/90 mm Hg) stwierdzono u 30% pacjentów po 24 miesiącach od ablacji tętnic nerkowych. Wnioski: W grupie badanych chorych przezskórna ablacja tętnicy nerkowej skutecznie obniżyła skurczowe i rozkurczowe BP oraz ciśnienia tętna. Nie stwierdzono istotnych zdarzeń niepożądanych w ciągu 24-miesięcznej obserwacji. Wyniki badań polskiej grupy pacjentów nie odbiegają w żaden sposób od wyników uzyskanymi w badaniach SIMPLICITY I i II

Clinical factors predicting blood pressure reduction after catheter-based renal denervation

Introduction: Renal denervation (RD) can lead to a significant and sustained decrease in mean values of arterial blood pressure (BP). However, there is still a subset of patients without a significant BP drop after RD (non-responders). Aim: To compare characteristics of RD responders to RD non-responders and to identify the clinical predictors of BP reduction. Material and methods: Thirty-one patients with diagnosed resistant hypertension underwent RD. Three years after RD the analysis of BP reduction was performed in regard to the baseline patient characteristics. Results: After 3 years’ follow-up a 10% or more reduction of systolic baseline BP was observed in 74% of patients. Ten percent or more reduction of diastolic baseline BP was observed in 71% of patients. Among responders we observed the following risk factors: hypercholesterolemia in 70%, body mass index (BMI) > 30 kg/m2 in 55%, diabetes mellitus in 35%, current smoking in 5%. Comorbidity included coronary artery disease (CAD) in 30%, cardiomyopathy in 10%, chronic obstructive pulmonary disease (COPD) in 10%, renal insufficiency in 10%, and ventricular arrhythmia in 5%. Among non-responders we observed the following risk factors: hypercholesterolemia in 38%, diabetes mellitus type 2 in 38% and BMI > 30 kg/m2 in 86%. Comorbidity included CAD in 50% and cardiomyopathy in 13% of patients. Conclusions: A 10% reduction of systolic baseline BP was observed in 74% of patients 3 years after renal denervation. Clinical factors like COPD, chronic kidney disease 3a, female sex and hypercholesterolemia increase the chances of effective reduction of BP

Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes

The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR–GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0–2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal −44.9,−35.0, and −22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear and angular velocities

Antioxidative assessment of new trans-palladium (II) complexes in head and neck cancer

Background: Head and neck neoplasms stand for 6% of all malignant neoplasms worldwide. Chemotherapy has limited use due to the biological properties of the tumor (in the majority of cases moderately and poorly differentiated squamous cell carcinoma). The fundamental molecule used in treatment is cisplatin and its derivates, that can be associated with fluorouracil. The new chemotherapeutic agents are not in common use during the treatment of head and neck malignancies. However, the use of low molecular weight complexes Pd (II) carries the potential of being more effective in therapy. Material and Methods: Fifty-one patients, 30 men and 21 women (aged 52.9 ± 12.1 years) with head and neck cancer were included in the study. Fifty-one healthy subjects, 31 men and 20 women, (aged 54.1 ± 14.7 years) years formed the control group. Antioxidant enzymes, superoxide dismutase, and catalase activities in erythrocytes were examined. Results: An increased level of antioxidant enzymes was seen in the blood samples from patients with head and neck cancer after incubation with Pd (II) complex. In the group we obtained a statistically significant result p = <0.001. Discussion: That project may contribute to the development of new, more efficient head and neck cancer treatment strategies. In our opinion, the results can be used in the future to develop a valuable prognostic marker of the disease. This is important because the initial phase of cancer is asymptomatic. The search for factors involved in pathogenesis translates into economic benefits and makes therapy more effectiveness through the reduction of treatment expenses

A New Online Service for the Validation of Multi-GNSS Orbits Using SLR

In the last decade, we have been witnessing a rapid development of the constellations of Global and Regional Navigation Satellite Systems (GNSS/RNSS). Besides the well-known GPS and GLONASS, newly developed systems such as Galileo, BeiDou, QZSS and NAVIC have become increasingly important. All satellites of new GNSS are equipped with laser retroreflector arrays (LRA) dedicated to Satellite Laser Ranging (SLR). SLR allows, e.g., an independent validation of microwave-based orbit products. Therefore, a fully operational online service called the multi-GNSS Orbit Validation Visualizer Using SLR (GOVUS) has been developed allowing for near real-time analysis of the quality of multi-GNSS orbits. The mean offsets of SLR residuals for Center for Orbit Determination in Europe (CODE) orbits in 2016 are at the level of −8, −38, −14, and −107 mm, for BeiDou, Galileo, GLONASS, and QZSS, respectively, with the standard deviations of 66, 36, 29, and 100 mm. Moreover, GOVUS can be used as a database containing information on equipment used at SLR stations and multi-GNSS satellite parameters. This paper includes a comprehensive description of the functionality and the structure of the developed service with exemplary analyses. The paper points out the most critical issues, limitations and challenges of multi-GNSS and SLR tracking network in the context of the SLR orbit validation. The goal of the paper and GOVUS itself is to determine: (1) what is the current quality of multi-GNSS orbits validated using SLR results; (2) what kinds of systematic errors can affect GNSS orbits and SLR observations; and (3) how to provide the online analysis tools to the broadest possible multi-GNSS community. The service has been officially operating since March 2017 as the Associate Analysis Center of the International Laser Ranging Service (ILRS ACC)