Half Moon Research Articles

Estimating Visual Acuity Without a Visual Acuity Chart.

This study explored whether visual acuity (VA) can be inferred from self-reported ability to recognize everyday objects using a set of yes/no questions. Participants answered 100 yes/no questions designed to assess their ability to recognize familiar objects at typical viewing distances, such as distinguishing between a full moon and a half moon on a clear night. The questions demanded VA ranging from normal to severe vision impairment. Responses were analyzed using item response theory, and the results were compared with participants' VA values. We recruited 385 participants from 4 sites in the United States. Participants had a mean age of 56.7years with VA ranging from -0.3 to 2.0 logarithm of the minimum angle of resolution (logMAR) (mean = 0.58). A strong relationship was observed between participants' estimated vision ability and their VA (r = -0.72). The linear relationship can be used to predict each participant's VA based on their estimated vision ability. The average signed and unsigned prediction errors were 0 and 0.24 logMAR, respectively, with a coefficient of repeatability of 0.59 logMAR between the estimated VA and measured VA. The same linear function was used to determine the VA limit required for each question. For instance, the VA limit for the moon question was 1.0 logMAR. Yes/no questions about everyday visual activities have the potential to estimate an individual's VA. Future refinements may enhance reliability. The survey provides insights into the real-world visual capabilities of people with low vision, making it potentially useful for telehealth applications.

Antipredator displays of the Cuban Groundlizard (<i>Pholidoscelis auberi</i>) on Little San Salvador Island (Half Moon Cay), The Bahamas, and a review of similar behavior in other lizards

Antipredator behavior in the teiid lizard Pholidoscelis auberi is previously unreported. I observed an arm-waving display (AWD) and lateral undulation of the tail (LUT) in two P. auberi, an adult and a neonate, on Little San Salvador Island (Half Moon Cay), The Bahamas. Context indicated that these were antipredator behaviors. AWD was performed overhand (clockwise in right lateral view), with the elbow strongly flexed, and with one arm at a time. AWD is performed similarly in some other lizard species and differently in some others. AWD is previously unreported in P. auberi, and LUT is previously unreported in all but one other teiid species.

SUSTAINABLE USE OF GEOMORPHOLOGICAL FORMS IN TOURISM, THE CASE OF HALF MOON BAY, EASTERN REGION, KINGDOM OF SAUDI ARABIA

The Coastal geomorphology of the Half Moon Bay in the Eastern Region of Saudi Arabia has created great opportunity for human interventions. Public and private tourism and entertainment facilities were established along the Bay cost leading to modifications of natural phenomena. Therefore, this study aims at assessing tourism uses of geomorphological forms in the Half-moon Bay and identifying practical aspects related to sustainable tourism. It was based on literature review, field survey, analysis of google earth satellite imagery, risk analysis and SWOT analysis. Depending on the characteristics of the different coastal forms, various tourist activities were developed in the study area. However, environmental alterations, such as change of direction, length and meander of coastline have been recognized mainly, due to land excavation and backfilling of shallow sea water. Despite some constrains, several opportunities are available in order to promote and develop sustainable tourism in the region mainly supported by a set of legislations, efforts and actions at the national and local levels.

Evolution of an earthquake-induced landslide complex in the South Island of New Zealand: How fault damage zones and seismicity contribute to slope failures

Abstract Tectonic deformation within fault damage zones can influence slope stability and landslide failure mechanisms due to rock mass strength effects and the presence of tectonic structures. Here, we used detailed site investigations to evaluate controls on deformation within the Half Moon Bay landslide complex, located ~1 km from the surface trace of the Hope fault in the South Island of New Zealand. During the 2016 Mw 7.8 Kaikōura earthquake, the slope experienced up to ~13 m of displacement and partially transitioned into a rock avalanche (with a volume of ~350,000 m3). Deep-seated deformation of the entire slope predated the 2016 earthquake. Results of geomorphological analysis, field mapping, geophysical surveys, slope displacement, and a 60-m-deep borehole in the incipient portion of the landslide indicated the presence of a subvertical tectonic fabric and intense fracturing and weathering of the rock mass, which gradually decrease with depth. Based on these results, we established a conceptual model wherein the landslide failure mechanism is a combination of flexural toppling along the subvertical structures coupled with joint-step-path sliding along preexisting, closely spaced discontinuities within the graywacke rock mass. Coseismic slope displacements revealed a large area of incipient failure behind the headscarp of the 2016 rock avalanche, which will likely result in further avalanching at the site. This case study demonstrates that inherited tectonic structures (combined with seismicity and weathering in an oversteepened coastal slope) play an important role in the evolution of hillslopes near active faults.

Babylonian House Numbers and Squares of Zodiacal Signs

The texts BM 36628+ and BM 45720 contain number schemes, which in their first four columns list consecutive lines of Calendar Texts. These texts add six more columns (columns 5–10) to the classic Calendar Text. Therefore, we shall call them expanded Calendar Texts. The additional column 10 lists house numbers j, while column 9 contains four signs (labeled i) over four consecutive lines, one of which equals a j-value. As we shall see, the i-values are chosen so that they always form the zodiacal squares with j as one of the corners. I investigate the system behind the schemes by analyzing their number columns. We thus find a structure similar to that of the circular tablet BM 47762, which I presented in Part I [Aestimatio ns 2.2 (2021) 43–58]. This tablet lists the dates of first half, full, second half, and black Moon, where the zodiacal position of these special lunar phases joins to a square in the zodiacal circle. I investigate the connection between the two systems.

New records and updated distributional patterns of macroalgae from the South Shetland Islands and northern Weddell Sea, Antarctica

AbstractThis study provides new species records (NRs) of macroalgal assemblages present in rocky habitats from the South Shetland Islands (SSI) and north-eastern Antarctic Peninsula (EAP), Weddell Sea. Surveys were conducted during the summers of 2013/2014 to 2017/2018 at Elephant, Deception, Half Moon and Vega islands. Data from the present study and those available in the literature from the western Antarctic Peninsula (WAP) were combined to provide an updated checklist, giving insights into macroecology and potential changes in thermohaline circulation patterns. A total of 48 macroalgal taxa were identified from our sampling, with eight representing NRs to the EAP sector of the Weddell Sea and five representing NRs to the SSI. Statistical differences among the assemblages from the SSI, WAP and EAP were identified. NRs, including opportunistic species and new information about the biogeographical distributions of species reported here, give insights into ecoregional connectivity and environmental changes. This study updates macroalgal diversity records in regions that are currently experiencing the impacts of climate change. Future and ongoing monitoring for conservation purposes is required to detect non-native species, new dispersal pathways and patterns related to thermohaline anomalies in Antarctic waters.

Internal Waves near Half Moon Island, South Shetland Islands

Internal Waves near Half Moon Island, South Shetland Islands

Internal Waves Near Half Moon Island, South Shetland Islands

We analyze internal waves based on measurements on cruise 87 of the R/V Akademik Mstislav Keldysh in the Bransfield Strait near Half Moon Island and calculations using a numerical model. The measurements were carried out on January 25, 2022 for four hours using a line of temperature and pressure sensors, along with the measurements with a CTD probe. Temperature fluctuations according to the sensors of the thermal line and the probe showed that the amplitude of internal waves is close to 5 m, sometimes reaching 15 m. According to the results of calculations of the global tidal model TPXO9, irregular semidiurnal tides predominate in the study area. Numerical calculations of the parameters of internal waves show that the baroclinic tide generated on a steep slope breaks up into higher frequency waves.

The role of serum immunoglobulin e in patients with immunoglobulin А-nephropathy

THE AIM. To determine the frequency of elevated serum immunoglobulin E (IgE) levels in patients with immunoglobulin A nephropathy (IGAN) and to establish its relation to clinical and morphological, laboratory manifestations and disease course. PATIENTS AND METHODS. The study enrolled 47 patients with primary IGAN, age 32 (27 ÷ 39) years. Daily proteinuria (PU), hematuria, serum creatinine, degree of arterial hypertension (AH) and glomerular filtration rate (GFR) were analyzed. Blood concentration of total IgE was determined by enzyme immunoassay, and allergen-specific IgE antibodies to 57 allergens (domestic, epidermal, fungal, vegetable, food) using a commercial kit "EUROLINE Atopy Screen (IgE)" ("Euroimmun", Germany). RESULTS . In patients with IGAN, serum total IgE was found to exceed the normal value in 55 % of cases, with a concentration of 89.4 (47.5 ÷ 198.7) IU/ml and correlation with GFR (R=0.32, p=0.02) and creatinine (R=-0.40, p=0.01) was detected. Patients with elevated IgE levels showed a reduced incidence of AH (p=0.01), tubular atrophy and interstitial fibrosis (T1) (p=0.03). A correlation analysis revealed that the severity of endothelial proliferation decreased with increasing IgE concentration (R=– 0.40, p=0.02). The highest prevalence among allergens was shown for specific IgE to domestic mites Dermatophagoides farinae (42,1 %), specific activity of 31,4 (1,7 ÷ 71,3) u.u. was noted to Dermatophagoides pteronyssinus. There was a correlation between IgE concentration to Dermatophagoides pteronyssinus and PU (R=-0.51, p=0.01) and between the amount of IgE to Dermatophagoides farinae and the percentage of half moon (R=-0.55, p=0.01). The five-year event-free survival rate was 67 ± 19 % in the IgE group within normal limits and 100 % in the IgE group above normal limits (p=0.008). CONCLUSION. The presence of elevated concentrations of total and specific IgE indicated a more favourable course of IGAN.

Half Moon Summer by Elaine Vickers

Reviewed by: Half Moon Summer by Elaine Vickers Kara Forde Vickers, Elaine Half Moon Summer; illus. by Chloe Zola. Peachtree, 2023 [288p] Trade ed. ISBN 9781682635391 $17.99 E-book ed. ISBN 9781682635544 $10.99 Reviewed from digital galleys R Gr. 5-7 As summer vacation rounds the corner in Half Moon Bay, CA, Drew is dreading the expanse of time without his best friend Isaac, who recently moved away. Things begin to turn around when Drew’s dad gifts him a new pair of Nike running shoes and they start to run together, even though Drew has a sinking feeling about his dad’s new clumsiness and his parents’ secret conversations. Meanwhile, Mia is not at all happy to be in Half Moon Bay for the summer—instead of working on building their house in Sacramento, Mia’s dad heads to Alaska to care for his sick mother, while Mia and the rest of the family spend the summer with her maternal grandmother. When Mia’s and Drew’s paths converge, they begin to run together daily with the goal of participating in a half marathon at the end of the summer. At the event, Mia intends to confront the wealthy real estate developer who has put her family’s dream of living in their own home in jeopardy. An inviting preface foreshadows the main characters’ friendship with the story of Drew and Mia’s “Birth Day,” as the two shared a bassinet after they were born on the same day at the same hospital. Vickers deftly distinguishes between the alternating perspectives by composing Drew’s point of view in prose and Mia’s chapters in verse. Both main characters seem uncommonly self-reflective for almost-thirteen-year-olds, yet their perceptiveness and the parallels between their concerns about family finances and [End Page 342] relationships greatly enhance the emotional appeal of this story. News of a serious diagnosis for Drew’s dad highlights a tender theme of courage in face of the precariousness of life, evoking a deep gratitude for every precious moment spent with loved ones. Copyright © 2023 The Board of Trustees of the University of Illinois

The Supernova Remnant of More than 4100 Years Ago Was Discovered—Emperor Yao’s Jingxing (PKS 1209-52)

According to Bamboo Annals, “The year Emperor Yao ascended the throne was the year of Bingzi” and “In the forty-second year of his reign, Jing star appeared on the Yi xiu (constellation)”. LunHeng says that “during the era of emperor Yao, Jing star was seen in the Zhen xiu (constellation)”. This star may be a supernova between Yi xiu and Zhen xiu. Calculated by already known years that was designated by Heavenly Stems and Earthly Branches, the 42nd year of Emperor Yao’s reign was B.C.2164. If we take a wide range (180∘±23∘) as the transition area between ‘Yi’ and ‘Zhen’, we can find 20 supernovae in the Green Supernova Remnant Table. Among them, only the high silver latitude remnant PKS 1209-52 (G296.5+10.0) conforms to brightness and age limitations of Emperor Yao’s Jing star that appeared “like a half moon”. It is the only candidate of Emperor Yao’s Jing star (SN-B.C.2164). According to the relationship between the surface brightness of supernovae and the line diameter that SNR Σ∝D−β, as well as the adiabatic expansion theory, the adiabatic phase age (t=4165 yr) is calculated to be consistent with the era of Emperor Yao. In addition, according to the limitation that the Jing stars are as bright as “half moon”, the distance d= 1–1.2 kpc can be figured out. Then according to the Sedov relation D=0.94t2/5, the age of Emperor Yao’s Jing star was (4450 ± 900) years ago. It is also in accordance with the times of Emperor Yao. This is one of the earliest recorded supernovae in the history of astronomy, which advances the history recorded in Chinese literature and confirmed by science to more than 4100 years ago.

Pharmacognostical Study of Leaf of Hamsapadi (Adiantum Lunulatum)

Pharmacognostical evaluation of leaves of Adiantum lunulatum is done for identification in field and for differentiation from other species of Adiantum. Methods: A detailed literary work of drug studied and its pharmacognostical, phytochemical and analytical study including powder microscopy and taste determination of leaves with suitable instruments. Results: Macroscopic evaluation reveals the pinnacles are half moon shaped, alternate, sub-opposite or opposite in apical portion of the frond, having lobes with minor incisions. In microscopic structure the two surfaces of pinna are covered by epidermis and epidermal cells are wavy in outline. The opening and closing of stomata will be regulated by guard cells, whereas there is absence of stomata on epidermis. The vascular cells are lined by an endodermal tissue. Transverse section of petiole showed that it is externally covered by an epidermis lined by cuticle on its outer wall which renders the petiole to be shining. Below the epidermis is a fairly thick hypodermis made up Sclerenchyma cells of 4-5 layers in thickness. They are dead cells compact in arrangement and look dark in colour. Powder microscopy of leaves reveals shows few Tracheids of the veins and the Parenchyma cells of the leaves. The Sori are very prominent structures occurring at the leaf margin, they are visible characteristically under the microscope. The Sori contain number of Sporangia each Sporangium is lined by cells with U shaped thickening having their outer wall thin in nature. Conclusion: This study will help in Authentication of Hamspadi plant.

Antarctic tourism: spatial structure and dynamics of international tourist flows (for the seasons of 2011-2020)


 
 
 The theoretical foundations of the origin and development of Antarctic tourism are considered. The first proposals for Antarctic tourism were recorded in 1910, but it was not until the 1920s that the first tourists were able to visit the mainland. The beginning of commercial tourism to the Antarctic was laid by Lars-Erik Lindblad on his cruise liner «Explorer», which in 1966 made the first commercial tourist flight to the continent. In the 1980s of the 20th century, Antarctica was visited annually by about 2,000 tourists. In the 1990s, Antarctic tourism became a mass phenomenon, flights over the Antarctic resumed. The Antarctic Treaty system is considered. In 1959, the Antarctic Treaty was concluded, and in 1961, it established the status quo, which prohibits the making of new territorial claims and the expansion of old claims made before 1959. The treaty declares the freedom of scientific research in the Antarctic. It has been analyzed that the current lack of territorial possessions of one or another country in the Antarctic facilitates the conduct of comprehensive scientific research. It has been established that in Ukraine only one dissertation study is devot- ed to the issues of Antarctic tourism. All other works of scientists are devoted to biological, gravimetric, mineralogical, geodetic, ocean- ographic, physical, geological research of the Antarctic. It has been proven that modern directions of regional complex geographical re- search of the Antarctic are closely related not only to the provision of national interests, but also to the solution of global environmental problems. An analysis of the spatial structure and dynamics of international tourist flows to the Antarctic was conducted for the seasons 2011-2020. During this period, 389,800 people visited the continent. There is a constant increase in the number of visitors. Travel by mode of transport is considered. During the entire period of the study, the largest number of visitors (71.5% of the total number) usedcruise ships / yachts with a landing on the shore with an excursion to the mainland. An analysis of the distribution of tourists by country of origin was carried out. The Top-20 places of Antarctica, which are the most visited, are considered. During the 2016-2017 – 2019-2020 seasons, the number of visits reached 7,086. The top five are occupied by Cuverville Island (9.07% of the total number of visits during the study period), Goudier Island (8.65%), Neko Harbor (8.55%), Whalers Bay (8.24%), Half Moon Island – Chinstrap Colony (7.83%). The station «Akademik Vernadsky” ranks 13th with 194 visits, which is 2.74%. The most popular tourist destinations in East Antarctica for the 2019-2020 season have been reviewed: Amundsen Sea with ship cruises, Cape Evans with small boat cruises and shore landings, Cape Adare with ship cruises, small boat cruises and shore landings from it to the shore. It is noted that at the current stage of the development of society, it is impossible to forecast the tourist flow to the Antarctic for the coming season with the help of economic and mathematical modeling in connection with the COVID-19 coronavirus pandemic.
 
 

Fluvial responses to late Holocene hydroclimate variability in the midcontinental United States

Long-term relationships between mean-state climatic conditions and flood frequencies in the midcontinental United States (US) are not well established because instrumental records of fluvial processes are limited to the current warm period (CWP; the last ca. 150 years) and continuous paleo-flood records are exceedingly rare. Here, we investigate climate-flood relationships in the midcontinental US by reconstructing flood frequencies at Half Moon Pond, a 1600-year-old oxbow lake on the lower White River, Indiana (watershed = ca, 29,000 km2). We used sediment accumulation rates and clastic fluxes constrained by high-resolution radiocarbon (14C) dating. Frequent flooding, as indicated by high sedimentation rates and clastic fluxes to Half Moon Pond, occurred leading up to and during the Medieval Climate Anomaly (MCA; 950–1250 CE) when paleoclimate records suggest the predominance of ocean-atmosphere mean states resembling the negative phases of the Pacific Decadal Oscillation (-PDO-like) and Pacific North American Mode (-PNA-like). Reductions in sedimentation rates and clastic fluxes, indicating reduced flooding, subsequently occurred during the transition out of the MCA and into the Little Ice Age (LIA; 1250–1830 CE) as ocean-atmosphere conditions shifted to + PDO-like and +PNA-like mean states. Sedimentation rates and clastic fluxes increased again after ca. 1800 CE, indicating increased flooding during the CWP as ocean-atmosphere conditions returned to -PDO-like and -PNA-like mean states. The White River trends were notably antiphased with sedimentation-rate-based flood frequencies for the lower Ohio River (500,000 km2 watershed) prior to 1830 CE. This antiphased relationship is consistent with flooding in moderate to small watersheds in the Midwest being sensitive to the occurrence of rainstorm events, which were more frequent leading up to and during the MCA, and flooding in large watersheds being more sensitive to large spring melts associated with extensive snowpacks, which characterized the LIA. That both the White and Ohio rivers experienced their most frequent flooding during the CWP suggests deforestation and changing land use practices increased flooding on Midwestern watersheds across scales despite a current climatic mean state that in the past only resulted in increased flooding on moderate to small watersheds. Continued increased in midcontinental rainfall are therefore likely to enhance the occurrence of floods in Midwestern watersheds across different geographic scales.

Thermal monitoring of a Cryosol in a high marine terrace (Half Moon Island, Maritime Antarctica).

Active layer and permafrost are important indicators of climate changes in periglacial areas of Antarctica, and the soil thermal regime of Maritime Antarctica is sensitive to the current warming trend. This research aimed to characterize the active layer thermal regime of a patterned ground located at an upper marine terrace in Half Moon Island, during 2015-2018. Temperature and moisture sensors were installed at different soil depths, combined with air temperature, collecting hourly data. Statistical analysis was applied to describe the soil thermal regime and estimate active layer thickness. The thermal regime of the studied soil was typical of periglacial environment, with high variability in temperature and water content in the summer, resulting in frequent freeze-thaw cycles. We detected dominant freezing conditions, whereas soil temperatures increased, and the period of high soil moisture content lasted longer over the years. Active layer thickness varied between the years, reaching a maximum depth in 2018. Permafrost degradation affects soil drainage and triggers erosion in the upper marine terrace, where permafrost occurrence is unlikely. Longer monitoring periods are necessary for a detailed understanding on how current climatic and geomorphic conditions affect the unstable permafrost of low-lying areas of Antarctica (marine terraces).

Study of performance characteristics of ANVIS MK-III night-vision goggle and comparison with other NVGs for aviation usage

Objectives: Night Vision Goggles (NVGs) are widely used in military aviation. Performance of an NVG in terms of high resolution and target acquisition is considered a critical requirement. Gen III NVGs have been considered superior to Gen II and Gen II++ NVGs. The purpose of the study was to evaluate the performance characteristics of ANVIS MK-III NVG and compare them to those of other available NVGs. Material and Methods: ANVIS MK-III Gen III NVG was studied for its performance in terms of visual acuity (VA), contrast sensitivity, and field of view (FOV). Six subjects familiar with use of NVG participated in the study. VA was measured using USAF 1951 Tri-bar chart, while contrast sensitivity was measured using PelliRobson chart under full-moon (FM), half-moon (HF), quarter-moon (QM), and starlight (SL) conditions. The FOV was measured using Cross Bar chart. Comparisons were made with the data of other NVGs available with the Institute. Results: The mean VA of ANVIS MK-III NVG was found to be 20/29, 20/31, 20/34, and 20/39 under of FM, HF, QM, and SL illumination conditions, respectively. The mean contrast sensitivity was 0.9, 0.75, 0.6, and 0.53 log CS units, respectively, with mean FOV of 39.5°. The results were compared with performance characteristics of NL 93, GEO1, and F4949 NVGs. Conclusion: The ANVIS MK-III NVG was found to have higher VA function as compared to other NVGs and better contrast sensitivity function as compared to NL-93 and GEO1 NVG. All the NVGs had comparable FOV. The ANVIS Mk-III NVG in the current configuration with Helmet Display and Tracking System was found to be heavier and needs further ergonomic evaluation.

First High-Power CSEM Field Test in Saudi Arabia

We conducted an initial high-power CSEM (controlled-source electromagnetic method) survey in a coastal salt-flat area in the broader area of Half Moon Bay, in the southern part of Dammam Peninsula in the eastern province of Saudi Arabia. The primary purpose of this work was to verify the technology, but we were also able to detect and characterize potential economic brines in the study area. For a high-quality data acquisition, several transmitter–receiver configurations, different acquisition parameters, and passive and active EM data were collected, evaluated, processed, and interpreted to characterize the subsurface. The long-offset EM (LOTEM) and the focused-source EM (FSEM) were the optimum configurations due to the high-quality of the collected data. This is a starting point for using the CSEM method towards the O&G, geothermal, CO2 sequestration, groundwater, lithium brine, and other natural resources’ exploration and exploitation in the Gulf countries.

Impact of the Temperature in Endophytic Ascomycota Isolated from Antarctic Hair-Grass

Antarctica is one of the most inhospitable continents on the planet, with lichens and mosses being the most common terrestrial organisms in ice-free areas. Antarctica is represented by only two species of Angiosperms, Deschampsia antarctica Desv. (Poaceae) and Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae). In this study, we characterized fungi isolated from the fresh leaves of this grass species. The fungi were isolated from four individual plants from Half Moon Island (246 leaf fragments investigated), and seven from King George Island-Keller Peninsula (with 111 leaf fragments investigated) Antarctica. Neoascochyta paspali, Septoriella elongata, Pyrenophora cf. chaetomioides and Alternaria sp. were associated with the plant and identified through analysis of the sequences of the internal transcribed spacer region (ITS) of the rDNA and nuclear ribosomal large subunit rRNA gene (LSU) as well as through macro and micro-morphological characteristics. The isolates showed higher growth rate ranging from 10 to 20 °C. An interesting result was that the aforementioned fungi are already recognized as both plant pathogens and endophytic fungi. The results demonstrate that D. antarctica is an interesting fungal source. Those species might provide important information about the relationship on the endemic Antarctic biota.

An Experimental Study on the Biomechanical Effectiveness of Bone Cement-Augmented Pedicle Screw Fixation with Various Types of Fenestrations.

To analyze the effects of the number and shape of fenestrations on the mechanical strength of pedicle screws and the effects of bone cement augmentation (BCA) on the pull-out strength (POS) of screws used in conventional BCA. For the control group, a conventional screw was defined as C1, a screw with cannulated end-holes was defined as C2, a C2 screw with six pinholes was defined as C3, and the control group type was set. Among the experimental screws, T1 was designed using symmetrically placed thru-hole type fenestrations with an elliptical shape, while T2 was designed with half-moon (HM)-shaped asymmetrical fenestrations. T3 and T4 were designed with single HM-shaped fenestrations covering three pitches and five pitches, respectively. T5 and T6 were designed with 0.6-mm and 1-mm wider fenestrations than T3. BCA was performed by injecting 3 mL of commercial bone cement in the screw, and mechanical strength and POS tests were performed according to ASTM F1717 and ASTM F543 standards. Synthetic bone (model #1522-505) made of polyurethane foam was used as a model of osteoporotic bone, and radiographic examinations were performed using computed tomography and fluoroscopy. In the fatigue test, at 75% ultimate load, fractures occurred 7781 and 9189 times; at 50%, they occurred 36122 and 82067 times; and at 25%, no fractures occurred. The mean ultimate load for each screw type was 219.1±52.39 N for T1, 234.74±15.9 N for T2, 220.70±59.23 N for T3, 216.45±32.4 N for T4, 181.55±54.78 N for T5, and 216.47±29.25 N for T6. In comparison with C1, T1, T2, T3, T4, and T6 showed significantly different ultimate load values (p<0.05). However, when the values for C2 and the fenestrated screws were evaluated with an unpaired t test, the ultimate load value of C2 significantly differed only from that of T2 (p=0.025). The ultimate load value of C3 differed significantly from those of T1 and T2 (C3 vs. T1 : p=0.048; C3 vs. T2 : p<0.001). Linear correlation analysis revealed a significant correlation between the fenestration area and the volume of bone cement (Pearson's correlation coefficient r=0.288, p=0.036). The bone cement volume and ultimate load significantly correlated with each other in linear correlation analysis (r=0.403, p=0.003). Fenestration yielded a superior ultimate load in comparison with standard BCA using a conventional screw. In T2 screws with asymmetrical two-way fenestrations showed the maximal increase in ultimate load. The fenestrated screws can be expected to show a stable position for the formation of the cement mass.

Perchlorate-reducing bacteria from Antarctic marine sediments.

Perchlorate is a contaminant that can persist in groundwater and soil, and is frequently detected in different ecosystems at concentrations relevant to human health. This study isolated and characterised halotolerant bacteria that can potentially perform perchlorate reduction. Bacterial microorganisms were isolated from marine sediments on Deception, Horseshoe and Half Moon Islands of Antarctica. The results of the 16S ribosomal RNA (rRNA) gene sequence analysis indicated that the isolates were phylogenetically related to Psychrobacter cryohalolentis, Psychrobacter urativorans, Idiomarina loihiensis, Psychrobacter nivimaris, Sporosarcina aquimarina and Pseudomonas lactis. The isolates grew at a sodium chloride concentration of up to 30% and a perchlorate concentration of up to 10,000mg/L, which showed their ability to survive in saline conditions and high perchlorate concentrations. Between 21.6 and 40% of perchlorate was degraded by the isolated bacteria. P. cryohalolentis and P. urativorans degraded 30.3% and 32.6% of perchlorate, respectively. I. loihiensis degraded 40% of perchlorate, and P. nivimaris, S. aquimarina and P. lactis degraded 22%, 21.8% and 21.6% of perchlorate, respectively. I. loihiensis had the highest reduction in perchlorate, whereas P. lactis had the lowest reduction. This study is significant as it is the first finding of P. cryohalolentis and. P. lactis on the Antarctic continent. In conclusion, these bacteria isolated from marine sediments on Antarctica offer promising resources for the bioremediation of perchlorate contamination due to their ability to degrade perchlorate, showing their potential use as a biological system to reduce perchlorate in high-salinity ecosystems.