Amount Of Debris Research Articles

Knowledge-Informed Data-Driven Modeling of Coupled Human-Built–Natural Systems: The Case of Hurricane-Induced Debris

Debris is one of the most challenging cascading effects posed by hurricane events, causing large financial and logistical burdens to coastal communities. Moreover, disaster debris can have cascading consequences on the safety and functionality of infrastructure, inhibit community recovery efforts, and lead to public health concerns. However, existing debris predictive models have shown an unsatisfactory performance, with errors up to 50% in debris estimates, and only consider a limited set of predictive variables. Given the importance of debris in coastal community resilience, this study leveraged a convergent research strategy to propose a knowledge-informed data-driven methodology by developing a comprehensive database that expands across human-built–natural systems to inform a probabilistic data-driven model of debris volume. A Gaussian process model was used to generate the debris volume model from a debris removal database for Hurricane Ike and the human-built–natural systems predictors. Moreover, different spatial resolutions (500, 250, and 125 m) were tested to analyze their effect on the model performance. Results showed that the low-resolution (500 m) and the intermediate-resolution (250 m) models have the best performance with a normalized root-mean squared error (RMSE) of 0.49 and 0.50, respectively. These two models were then used to explore the relative variable importance of the predictive variables in the model in order to get insights on the drivers of the debris process and propose more flexible lower-dimensionality models. The influence of different predictors and the trade-offs of resolution and model performance were also discussed before demonstrating application of the model for a synthetic storm in the Galveston, Texas, region. The proposed methodology and the probabilistic estimates of debris quantities are key to develop comprehensive risk estimates of storm impacts on coastal communities and can support informed decision making and mitigation planning strategies.

Star Wars: Anti-Satellite Weapons and Orbital Debris

ABSTRACT The militarization and weaponization of outer space are increasing continuously with the development of new and more advanced space weapon systems by a growing number of nations. This is a direct consequence of the high and growing strategic value of outer space for defense, security, and warfare. This paper reviews trends in space weapon systems and analyzes the implications of anti-satellite military weapons for human activities in outer space. A direct consequence of the completion of anti-satellite military tests is that the amount of orbital debris has increased significantly. We use a simple physical – economic model to illustrate how anti-satellite military tests, particularly those using direct-ascent weapons, dramatically increase the probability that the Kessler syndrome will occur. Whereas the long-run impact of low altitude anti-satellite tests is limited because of atmospheric drag, at high altitude direct-ascent anti-satellite tests are persistently harmful for human activities in space. The paper also provides a simulation of the long-run effects of a war in space.

A Comparative Evaluation of the Apically Extruded Debris from Root Canals Prepared by R-Motion NiTi File System.

Apically extruded debris (AED) is an inherent concern during root canal treatment for both endodontists and general practitioners. The present study investigates the AED of the novel R-Motion single-file reciprocating system compared to standard single reciprocating and multifile rotary systems. Fifty-six moderately curved palatal roots of upper maxillary first molars were selected for the present study. The samples were then divided randomly into four groups (n = 14)- Group I: R-motion (RM), Group II: WaveOne Gold (WOG), Group III: ProTaper Next (PTN), and Group IV: HyFlex EDM (HFEDM). The researcher has modified Myers and Montgomery's method to simulate human body temperature. Vials were used to collect debris and weighted using a 0.00001 sensitive balance before and after instrumentation. The instrumentation of all experimented groups was done at 37°C, terminated at master apical file #25. An auto syringe with a side vented needle was used to deliver 8 ml of deionized water for irrigation of each sample during preparation. Vials were stored in a dry sealed desiccator which contained CaSO4 crystals, for 24 hr before weighing. The weight of the collected debris was obtained by subtracting the preinstrumentation weight from the postinstrumentation weight for each vial. The Kruskal-Wallis and Mann-Whitney U tests were performed to analyse the statistical difference in the amount of debris between the tested groups at a 0.05 significance level. The RM system produced less debris extrusion than all tested groups, with a significant difference between the former and the WOG and the PTN systems. However, WOG, PTN, and HFEDM showed no statistically significant difference in the amount of AED. All tested groups produced apical debris in different amounts. The RM produced substantially less AED than WOG and PTN. Meanwhile, WOG, PTN, and HFEDM caused a comparable amount of AED.

A Comparative Study on the Shaping Ability and Cleaning Efficiency of Two Different Single-File Systems, Reciprocating Wave One Versus Continuous Rotation F360, Evaluated by Scanning Electron Microscope: An In Vitro Study.

Background: In endodontics, the three processes of biomechanical preparation, disinfection, and obturation are each essential. The electron microprobe and scanning electron microscope (SEM) allowed for the detection and identification of the smear layer and debris. The purpose of the current investigation was to use a scanning electron microscope to evaluate the relative merits of two single-file systems, the reciprocating WaveOne and the continuous motion F360 files, in the cleaning and contouring of root canals in removed teeth. Materials and method: The 50 central maxillary permanent teeth Data was gathered from the Oral and Maxillofacial Surgery Division at Sri Ganganagar's Maharaja Ganga Singh Dental College and Research Centre for a number of reasons. Group A followed the manufacturer's guidelines for using the WaveOne instrument, whereas Group B utilised the F360. Reciprocating motion WaveOne system (group A) and continuous motion F360 system (group B) root canals were scored at three levels: coronal third, middle third, and apical third (group B). SPSS version 22 was used for the data analysis. The data were examined using the chi-square test and the one-way analysis of variance. Results: A greater quantity of smear layer was found in the apical third, whereas better results were achieved in the coronal and middle thirds. When compared to the F360 file system, the WaveOne file system is subpar when it comes to clearing the canal of debris. While both groups showed a large amount of debris in the apical third, outcomes were somewhat better in the coronal and middle thirds. Conclusion: The WaveOne and F360 file systems were both more effective in removing trash from the coronal and middle thirds of the disc than they were from the apical thirds. In comparison to the continuous motion F360 file system, WaveOne files demonstrated a statistically significant reduction in the amount of debris cleared from root canals in all three root zone thirds (coronal, middle, and apical). The reciprocating action of the WaveOne file system, in contrast to the continuous motion of the F360 file system, resulted in more extensive cleaning of the root canal smear layer in the coronal and middle thirds and less thorough cleaning in the apical thirds of the canal.

Reviving the Low-Frequency Response of a Rupestrian Church by Means of FDTD Simulation

Rupestrian churches are spaces obtained from excavation of soft rocks that are frequently found in many Mediterranean countries. In the present paper the church dedicated to Saints Andrew and Procopius, located close to the city of Monopoli in Apulia (Italy) is studied. On-site acoustical measures were made, obtaining a detailed description of the acoustics in the current state pointing out, thanks to a combination of analysis techniques, the presence of significant modal behavior in the low frequencies, causing reverberation time to be about 2 s, four times longer than in the other bands, as well as being strongly dependent on source and receiver position (with variations of about 1 s when source is moved outside the chancel). However, as the church is characterized by significant degradation of surfaces and large amounts of debris cover the floor, the original acoustic conditions can be expected to somewhat differ. Acoustical modelling can be very helpful in grasping the original conditions, but given the small dimensions of the space, conventional geometrical acoustic prediction methods cannot be applied to simulate the low-frequency behavior. Thus, the present paper proposes an application of finite-difference-time-domain (FDTD) computation to simulate the low-frequency behavior and analyze a possible reconstruction of the original state. Results showed that a very good agreement was obtained between predictions and measurements, both in terms of resonance frequencies and reverberation times that differed by less than 5%. Modal response strongly affected the acoustical conditions also in the hypothetical reconstruction of the original state, although the sound field proved to be more uniform than in the current state.

COVID-19 personal protective equipment (PPE) contamination in coastal areas of Granada, Spain

The use of disposable personal protective equipment (PPE) as a control measure to avoid transmission against COVID-19 has generated a challenge to the waste management and enhances plastic pollution in the environment. The research aims to monitor the presence of PPE waste and other plastic debris, in a time interval where the use of face mask at specific places was still mandatory, on the coastal areas of Granada (Spain) which belongs to the Mediterranean Sea. Four beaches called La Rijana, La Charca, La Rábita and Calahonda were examined during different periods. The total amount of sampled waste was 17,558 plastic units. The abundance, characteristics and distribution of PPE and other plastic debris were determined. Results showed that the observed amount of total plastic debris were between 2.531·10−2 and 24.487·10−2 units per square meter, and up to 0.136·10−2 for PPE debris, where face masks represented the 92.22 % of the total PPE debris, being these results comparable to previous studies in other coastal areas in the world. On the other hand, total plastic debris densities were in the range from 2.457·10−2 to 92.219·10−2 g/m2 and densities were up to 0.732·10−2 for PPE debris. PPE debris supposed 0.79 % of the weight of total waste and the 0.51 % of total items. Concerning non-PPE plastic waste: cigarettes filters, food containers and styrofoam were the most abundant items (42.95, 10.19 and 16.37 % of total items, respectively). During vacation periods, total plastic debris amount increased 92.19 % compared to non-vacation periods. Regarding type of beaches, the presence of plastic debris was significantly higher on touristic/recreational than in fishing beaches. Data showed no significant differences between accessible and no-accessible beaches, but between periods with restrictive policy about mask face use and periods with non-restrictive policy data suggest significant differences between densities (g/m2) for PPE litter. The amount of PPEs debris is also correlated with the number of cigarettes filters (Person's r = 0.650), food containers (r = 0.782) and other debris (r = 0.63). Finally, although interesting results were provided in this study, further research is required to better understand the consequences of this type of pollution and to provide viable solutions to this problem.

Zebrafish cutaneous injury models reveal that Langerhans cells engulf axonal debris in adult epidermis.

Somatosensory neurons extend enormous peripheral axons to the skin, where they detect diverse environmental stimuli. Somatosensory peripheral axons are easily damaged due to their small caliber and superficial location. Axonal damage results in Wallerian degeneration, creating vast quantities of cellular debris that phagocytes must remove to maintain organ homeostasis. The cellular mechanisms that ensure efficient clearance of axon debris from stratified adult skin are unknown. Here, we established zebrafish scales as a tractable model to study axon degeneration in the adult epidermis. Using this system, we demonstrated that skin-resident immune cells known as Langerhans cells engulf the majority of axon debris. In contrast to immature skin, adult keratinocytes did not significantly contribute to debris removal, even in animals lacking Langerhans cells. Our study establishes a powerful new model for studying Wallerian degeneration and identifies a new function for Langerhans cells in maintenance of adult skin homeostasis following injury. These findings have important implications for pathologies that trigger somatosensory axon degeneration.

Orbital debris and the market for satellites

This paper studies the economic consequences of orbital debris for commercial outer-space activities. Spacecraft launches and other outer-space human activities produce pollution (i.e., orbital debris), which represent a hazardous negative externality increasing the risk of collision and the destruction of satellites. We regard outer space as a global common resource, where firms operating satellites maximize profits and do not internalize the social cost of orbital pollution. We develop a dynamic investment model for satellites and simulate the calibrated model to estimate how debris affects the optimal quantity of satellites and launches, and the number of satellites destroyed by collisions. We find that the optimal quantity of satellites is a negative function of the amount of debris. The paper derives a simple expression for the maximum number of satellites to prevent the Kessler syndrome. For the baseline calibration of the model, the estimated threshold for the maximum number of satellites in orbit is about 72,000. The model is simulated to study the effects of a decline in the launch cost and the increasing number of satellites per launch.

Instant deep sea debris detection for maneuverable underwater machines to build sustainable ocean using deep neural network

Deep sea debris is any persistent man-made material that ends up in the deep sea. The scale and rapidly increasing amount of sea debris are endangering the health of the ocean. So, many marine communities are struggling for the objective of a clean, healthy, resilient, safe, and sustainably harvested ocean. That includes deep sea debris removal with maneuverable underwater machines. Previous studies have demonstrated that deep learning methods can successfully extract features from seabed images or videos, and are capable of identifying and detecting debris to facilitate debris collection. In this paper, the lightweight neural network (termed DSDebrisNet), which can leverage the detection speed and identification performance to achieve instant detection with high accuracy, is proposed to implement compound-scaled deep sea debris detection. In DSDebrisNet, a hybrid loss function considering the illumination and detection problem was also introduced to improve performance. In addition, the DSDebris dataset is constructed by extracting images and video frames from the JAMSTEC dataset and labeled using a graphical image annotation tool. The experiments are implemented on the deep sea debris dataset, and the results indicate that the proposed methodology can achieve promising detection accuracy in real-time. The in-depth study also provides significant evidence for the successful extension branch of artificial intelligence to the deep sea research domain.

Research on the Efficient Space Debris Observation Method Based on Optical Satellite Constellations

The increasing amount of space debris poses a major threat to the security of space assets. The timely acquisition of space debris orbital data through observations is essential. We established a mathematical model of optical satellite constellations for space debris observation, designed a high-quality constellation configuration, and designed a space debris tracking observation scheduling algorithm. These tools can realize the efficient networking of space debris from a large number of optical satellite observation facilities. We designed a constellation consisting of more than 20 low-Earth orbit (LEO) satellites, mainly dedicated to the observation of LEO space objects. According to the observation scheduling method, the satellite constellation can track and observe more than 93% of the targets every day, increase the frequency of orbital data updates, and provide support for the realization of orbital space debris cataloguing. Designing optical satellite constellations to observe space debris can help realize the advance perception of dangerous collisions, timely detect dangerous space events, make key observations about high-risk targets, greatly reduce the false alarm rate of collisions, and provide observational data support for space collisions.

Evaluation of Apically Extruded Debris and Cleaning Efficiency of the Pediatric Rotary File System and the Manual Nickel-Titanium File System.

Background This study aimed to assess and compare the Kidzo pediatric rotary file system with the manual nickel-titanium (NiTi) K-file system used for preparing the root canal of primary mandibular second molars by measuring the total apically extruded debris utilizing a sensitive microbalance and assessing cleaning efficiency using a scanning electron microscope. Methodology A total of 46 mandibular second primary molars were instrumented using a pediatric rotary system (Elephant Kidzo, India) and a manual NiTi K-file system (Endostar, Poldent, Poland). The debris released from the apex was retrieved and dried in Eppendorf tubes that were weighed beforehand. The total extruded debris was determined using a digital electronic scale, following which the molar roots were vertically sectioned, and the canal walls were investigated at the apical, middle, and coronal levels by a scanning electron microscope for debris and smear layer. Results The Kidzo pediatric rotary file system extruded a lesser amount of debris than the manual Endostar file system, but the difference was statistically not significant. Regarding cleaning efficiency, the debris originating in the apical and middle regions by employing the rotary filing technique was significantly less (p < 0.05); however, at the coronal level, there were no notable differences. Conclusions The Kidzo pediatric rotary system produced less apically extruded debris than the manual system and demonstrated better cleaning efficiency.

Comparison of the effect of different glide path files on amount of apically extruded debris in curved root canals.

It is essential to create a glide path before root canal preparation with nickel-titanium rotary files to avoid file breakage and preserve the original canal structure. The aim of this study was to compare the amount of apically extruded debris after using different glide path files. A total of 96 first mandibular molars with curved mesial roots were randomly divided into six groups (n=16) which are K-files, Proglider, R-Pilot, TruNatomy Glider, WaveOne Gold Glider and group without a glide path. Apically extruded debris was measured after glide path and canal preparation. The highest amount of debris was found in the control group without a glide path and using a glide path file caused less debris and significant differences were observed between R-Pilot, TruNatomy Glider, ProGlider, WaveOne Gold Glider and K-file groups. It may be recommended to create a glide path before root canal shaping to reduce the amount of extrusion debris from the apical. Especially in curved and narrow root canals, it is recommended to use an R-Pilot file before root canal shaping in order to reduce the amount of apically extruded debris.

Reducing plasma shielding effect for improved nanosecond laser drilling of copper with applied direct current

Laser drilling of copper faces challenges due to its high reflectivity and high thermal conductivity of the laser beam. To enhance laser drilling efficiency and hole surface quality, the copper substrate was applied with a direct current (DC) during a 355 nm nanosecond laser drilling process. It was found that introduction of the DC current played a noticeable role in reducing the entrance hole diameter, increasing the depth of the blind hole, decreasing the taper angle, improving the inner surface finish, and enhancing the hole integrity with less amount of debris at the hole exit. Explanation of the processing mechanism is provided by investigation effects of key processing parameters and modeling of DC current-induced magnetic field on the laser-induced plasma. The applied DC current through the copper substrate during laser drilling generated an induced magnetic field and the Lorentz force of the induced magnetic field limited the expansion of the laser-induced plasma in the direction parallel to the laser beam, which weakened the shielding effect of the plasma and thus improved the processing efficiency and hole quality of the nanosecond laser drilling. The study results may open a new path for efficient and high quality laser machining of reflective, high thermal and electrical conductive materials.

Payload Camera Breadboard for Space Surveillance—Part I: Breadboard Design and Implementation

The rapid increase of space debris poses a risk to space activities, so it is vital to develop countermeasures in terms of space surveillance to prevent possible threats. The current Space Surveillance Network is majorly composed of radar and optical telescopes that regularly observe and track space objects. However, these measures are limited by size, being able to detect only a tiny amount of debris. Hence, alternative solutions are essential for securing the future of space activities. Therefore, this paper proposes the design of a payload camera breadboard for space surveillance to increase the information on debris, particularly for the under-catalogued ones. The device was designed with similar characteristics to star trackers of small satellites and CubeSats. Star trackers are attitude devices usually used in satellites for attitude determination and, therefore, have a wide potential role as a major tool for space debris detection. The breadboard was built with commercial off-the-shelf components, representing the current space-camera resolution and field of view. The image sensor was characterized to compute the sensitivity of the camera and evaluate the detectability performance in several simulated positions. Furthermore, the payload camera concept was tested by taking images of the night sky using satellites as proxies of space debris, and a photometric analysis was performed to validate the simulated detectability performance.

The effect of different kinematics on apical debris extrusion with a single-file system

To compare the amount of extruded debris caused by different motions using a single-file system. Fifty mandibular first molar teeth were randomized into 5 groups (n = 10) according to the motion tested: Optimize Torque Reverse (OTR), TF Adaptive Motion (TFA), continuous rotation (CR), reciprocation motion (+ 150°, −30°) (REC), and Jeni motion (Jeni). One Curve single file 25/06 (Micro-Mega, Besançon, France) was used in all experimental groups. The root canals were irrigated with 2.5% NaOCl, and the extruded debris were collected at pre-weighted glass vials. The glass vials were kept inside an incubator for one week at 70 °C to dry out the irrigating solution. The extruded debris was quantified by subtracting the pre-instrumentation from the post-instrumentation weight of the glass vials. The time required for each instrumentation procedure was digitally recorded. All data were analyzed statistically with one way ANOVA and post hoc Tukey test (P < 0.05). All the motions extruded apically debris with Jeni mode caused significantly less debris extrusion than TFA, REC, and CR (P < 0.05) while no significant difference emerged with OTR. Preparation time was not significantly different in all groups. Within the limits of the present study, all the kinematics produced apically debris extrusion, with Jeni reporting a similar amount of debris compared with OTR and significantly less than TFA, REC, and CR. Preparation time was similar among the tested kinematics.

Testing of the Efficacy of Bee Probiotic Lactobacilli Under In Vivo Conditions

Abstract American foulbrood is amongst the most dangerous diseases of the bee-family affecting many honeybee colonies worldwide. In countries of European Union, based on veterinary legislation, the bee colonies tested positive to American foulbrood are eradicated with high economic losses. It is therefore necessary to look for effective prevention, especially by the using of natural ingredients such as probiotics. In this study, we used lactobacilli isolated from digestive tracts of adult healthy honey bees and selected based on their good probiotic properties and ability to inhibit the growth of Paenibacillus larvae. These isolates were identified as Lactobacillus brevis and Lactobacillus plantarum. Night cultures of both strains were used for the preparation of probiotic suspensions and pollen was selected as an appropriate carrier for application of probiotic lacto-bacilli to the hives. Half a litre of pollen suspension was prepared for each hive. The suspension for experimental hives contained probiotic lactobacilli in concentration of 107–108 CFU.ml−1. Bees in control hives received pollen suspension without addition of probiotic lacto-bacilli. The suspensions were supplied to bees three times, once a week. Before and during administration of probiotics, samples of honey bees from each hive were taken every week and numbers of lactobacilli, P. larvae, enterobacteria and coliform bacteria were determined in their digestive tracts. Four weeks after the first administration of probiotic-pollen solution the numbers of lactobacilli were increased approximately by 0.5 log. Before starting this experiment, P. larvae (approx. 107 CFU.ml−1) were detected in digestive tracts of honey bees. In the experimental group after 3 weeks and in the control group after 4 weeks, no viable counts of P. larvae were found. The numbers of enterobacteria, coliform bacteria and Bacillus sp. decreased in both groups. During the experiment the health and condition of the hives were monitored. In addition, also monitored were: the development of the bee colony, the number of dead bees, the amount of hive debris, the aggressiveness of the bees, and the amount of honey spun; later during the autumn treatment also the fall of Varroa jacobsoni was noted. In the experimental and control groups, we recorded a decrease in the amount of hive debris. Only in the experimental group was a slightly above-average development of the bee colony, slightly above-average honey yields and a 70 % lower drop of Varroa mites. Based on these results, we assumed that the probiotic-pollen solution had a positive influence on the composition of microbiota in bee digestive tracts and it can increase resistance to P. larvae. It also had a positive effect on the health and condition of the bee colony. Probiotic-free pollen solution showed similar but weaker effects.

Silicone implant surface roughness, friction, and wear

Some textured silicone breast implants with high average surface roughness (‘macrotextured’) have been associated with a rare cancer of the immune system, Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL). Silicone elastomer wear debris may lead to chronic inflammation, a key step in the development of this cancer. Here, we model the generation and release of silicone wear debris in the case of a folded implant-implant (‘shell-shell’) sliding interface for three different types of implants, characterized by their surface roughness. The ‘smooth’ implant shell with the lowest average surface roughness tested (Ra = 2.7 ± 0.6 μm) resulted in average friction coefficients of μ avg = 0.46 ± 0.11 across 1,000 mm of sliding distance and generated 1,304 particles with an average particle diameter of D avg = 8.3 ± 13.1 μm. The ‘microtextured’ implant shell (Ra = 32 ± 7.0 μm) exhibited μ avg = 1.20 ± 0.10 and generated 2,730 particles with D avg = 4.7 ± 9.1 μm. The ‘macrotextured’ implant shell (Ra = 80 ± 10 μm) exhibited the highest friction coefficients, μ avg = 2.82 ± 0.15 and the greatest number of wear debris particles, 11,699, with an average particle size of D avg = 5.3 ± 3.3 μm. Our data may provide guidance for the design of silicone breast implants with lower surface roughness, lower friction, and smaller quantities of wear debris.

Commentary: Retinal changes after internal limiting membrane peeling.

The internal limiting membrane (ILM) is the innermost of the 10 retinal layers. It is a transparent membrane measuring nearly 10 microns and is formed by the basement membrane of the Müller cells. It is peeled as a standard treatment of full-thickness macular hole (FTMH). However, many reports have shown that peeling the ILM may actually damage the retina. Wollensak et al.[1] showed that ILM removal reduces the mean strength of the central retina by almost half. Histological studies performed on human and primate eyes have shown that ILM peeling causes damage to the processes and end feet of the Müller cells. A selective delay has been noted in the B-wave recovery of focal macular electroretinogram in eyes that have undergone ILM peeling. Several anatomical changes have been described after ILM peeling.[2] Swelling of the arcuate nerve fiber layer (SANFL): It was first described by Clark et al.[3] as an early postoperative change. It is seen as hypoautofluorescent arcuate striae in the macular region on fundus autofluorescence (FAF) and infrared (IR) imaging; however, it cannot be detected on either biomicroscopic fundus examination or color photograph. It is seen as a hyperreflectant swelling on spectral domain optical coherence tomography (SD-OCT). It usually disappears gradually over a period of 2–3 months. It does not seem to affect the best-corrected visual acuity (BCVA) or retinal sensitivity. Dissociated optic nerve fiber layer (DONFL): It was first described by Tadayoni et al.[4] in 2001. It is also known as “concentric macular dark spots (CMDS)” or “inner retinal dimpling”.[2] It gives the macula a ‘‘moth-eaten’’ appearance due to the presence of small depressions on the retinal contour situated along the course of retinal nerve fibers on the en face scan. SD-OCT scans show that the depth of these dimples is limited to the RNFL only. Liu et al. found three distribution patterns, namely, papillomacular bundle-dominated, scattered, and temporal raphe-spared patters.[5] Ye et al.[6] showed that DONFL appeared within two months of surgery. The number progressed during the next four months and then slowed down. The number did not change after 12 months since the surgery. It has not been found to have association with either BCVA or retinal sensitivity. Steel et al.[7] showed that the use of a diamond-dusted membrane scraper to initiate the peel is a risk factor for the formation of DONFL. The extent of DONFL has been seen to be positively associated with the amount of cellular debris on the retinal side of the peeled ILM.[8] The perioperative optical coherence tomography (OCT) for ophthalmic surgery (PIONEER) study showed that the immediate increase in the inner retinal layer thickness on intraoperative OCT following ILM peeling was associated with the development of DONFL, while the technique used for peeling did not.[9] Foveal displacement: Several authors have reported a nasal shift of the fovea, that is, shortening of the foveopapillary distance (FPD). Ishida et al.[10] reported that the displacement was greater in the temporal retina compared to the nasal retina. They further reported that the degree of the retinal displacement significantly correlated with the maximum base diameter of the FTMH. However, Nair et al.[11] reported that a temporal foveal shift may be seen in around 25% of the eyes, especially those with a longer temporal segment. Ohta et al. reported that the steepness of the foveal slope increased after ILM peeling in an asymmetrical pattern as the nasal side became significantly steeper than the temporal one.[12] None of these findings seem to affect the BCVA or retinal sensitivity. Retinal thinning: Several studies have shown that the macular volume, especially that of the temporal macula, shows a progressive reduction.[2] It has been proposed that hemi-temporal ILM peeling is as effective as conventional 360-degree peeling for the treatment of FTMH. Additionally, it is associated with less retinal displacement, lesser DONFL formation, lower rates of subjective metamorphopsia, faster visual rehabilitation, and greater safety.[13–15] We congratulate the authors for their study showing that the outcomes of papillomacular bundle sparing ILM peeling is comparable to conventional ILM peeling in terms of hole closure rates and visual gain, with the advantage of less retinal damage for the treatment of idiopathic FTMH ≤400 microns.[16] Studies with larger sample size and larger macular hole size will help validate the surgical technique.

Investigation on beach debris on the historical nesting grounds of green turtles (Chelonia mydas) in Hainan Island, South China

Hainan Island used to be the most important nesting ground of green turtles in China before they disappeared about 37 years ago. Habitat degradation is one of the main reasons for the disappearance of sea turtles. Therefore, it is necessary to take action to evaluate and recover the historical nesting grounds if we hope for sea turtles to return in the future. In this study, we surveyed the beach debris on 13 historical nesting grounds of green sea turtles on Hainan Island. The beach debris on these nesting grounds mainly consisted of plastic, cigarette butts, foam, glass, and nylon, with plastic (including plastic blocks, cigarette butts, and foam) being the dominant type, accounting for 78.92% in number, followed by glass. The average density of beach debris was 0.314 pieces·m−2. Compared to other nesting grounds, the average quantity and density of beach debris in Hainan was lower, but the proportion of plastic debris was extremely high. After categorizing debris type, we found that most was from human coastal activities (35.54%), with debris at tourist beaches having the biggest proportion of debris from smoking supplies. The distribution characteristics of beach debris were related to the function of the beach, density of tourist, and the intensity of beach debris cleaning. It is recommended to further strengthen the emission reduction and clean-up of beach debris in Hainan Island, so as to restore the nesting habitat of sea turtles as soon as possible.

Potensi Sumber dan Sebaran Sampah Laut di Ekosistem Terumbu Karang Perairan Pulau Kelapa, Pulau Kelapa Dua, dan Pulau Harapan, DKI Jakarta

Pollution is a threat to coral reefs in Indonesian waters. The number of coral reefs that are in very good condition denies very little compared to the total area of ??coral reefs in Indonesia. One form of pollution that can threaten coral reefs is marine debris. This study aims to identify potential sources of marine debris that can disrupt the health of coral reefs. the research was carried out in the waters of Kelapa Island, Kelapa Dua Island and Harapan Island, DKI Jakarta. The data used includes current data obtained using secondary data, data on the amount of marine debris,and the water base data substrate obtained using the LIT method. The results showed that the waste was thought to come from community activities, tourism and fisheries. The location that can be a source of marine debris in the research location comes from the mainland of Jakarta Bay. The bottom substrate conditions are in the "bad" to "medium" category. The range of the lowest proportion of live coral cover is 10,8% and the highest live coral cover at 31.1%. The coral reefs in the research location are in a state of worry and their existence is threatened by pollution of marine debris.