Deeper Depths Research Articles

Assessment of Groundwater Quality and Vulnerability in the Nakivale Sub-Catchment of the Transboundary Lake Victoria Basin, Uganda

This study evaluates the quality and vulnerability of groundwater within the Nakivale Sub-catchment of the transboundary Lake Victoria Basin in Southwestern Uganda. Groundwater quality assessment focuses on its suitability for both drinking and agricultural uses. Hydrochemical analysis of 19 groundwater samples revealed that 90% comply with World Health Organization drinking water standards, although localized contamination was noted, particularly in terms of total iron, nitrate, potassium, magnesium, and sulfates. The drinking groundwater quality index shows that over 90% of the samples fall within the good-to-excellent quality categories. Elevated nitrate levels and chloride–bromide ratios indicate human impacts, likely due to agricultural runoff and wastewater disposal. For irrigation, Sodium Adsorption Ratio analysis revealed medium-to-high salinity hazards in the region, while Sodium Percentage and other parameters indicated low-to-moderate risks of soil degradation. DRASTIC vulnerability assessments identified low contamination risks due to impermeable geological layers, steep terrain, slow groundwater recharge, deep aquifer depth, and clayey soil cover. These findings emphasize the need for conjunctive water resource management, including improved groundwater quality monitoring, public education on sustainable practices, and protective measures for recharge zones and areas highly susceptible to contamination. By addressing these issues, this study aims to preserve groundwater resources for domestic and agricultural use, ensuring long-term sustainability in the region.

Aerobic and anaerobic poise of white swimming muscles of the deep-diving scalloped hammerhead shark: comparison to sympatric coastal and deep-water species

Scalloped hammerhead sharks (Sphyrna lewini) routinely perform rapid dives to forage on mesopelagic prey. These deep dives consist of intensive swimming followed by recovery periods in the surface mixed layer. Swimming muscle temperature profiles suggest that S. lewini suppresses gill function as a means to reduce convective heat loss during dives into cool water. Such intensive swimming behavior coupled with reduced respiration prompted us to test whether the aerobic and anaerobic metabolic capacities of the white swimming muscle tissue of this species are greater than those of other shark species from the same region. The activities of key enzymes used in aerobic and anaerobic metabolism provide an indirect indicator of the metabolic potential (“poise”) of a tissue. Here we measured the maximal activities [international units (µmol substrate converted to product per min, U) per gram of wet tissue mass at 10°C] of the citric acid cycle enzymes citrate synthase (CS) and malate dehydrogenase (MDH) and glycolytic enzymes pyruvate kinase (PK) and lactate dehydrogenase (LDH) from white swimming muscle of S. lewini. Enzyme activities, and ratios of these enzyme activities that indicate relative indexes of aerobic to anaerobic capacity, were compared to those measured in three sympatric coastal carcharhinid sharks and two deep-dwelling species, Echinorhinus cookei and Hexanchus griseus. This is the first report of swimming-muscle enzyme activity for these deep-dwelling species. In comparison to the other species, S. lewini had significantly higher activities of both LDH and MDH in the white muscle, and a higher MDH/CS ratio. The high LDH activities suggest that the white muscle of S. lewini relies on relatively high rates of anaerobic ATP production, with would result in build up of high lactate levels, during deep foraging dives. High MDH activity in S. lewini white muscle suggests the potential for lactate levels to be rapidly reduced when aerobic conditions are restored while in the surface mixed layer between dives. These biochemical characteristics may enable S. lewini to swim rapidly while suppressing gill function during deep dives and thereby exploit a very different ecological niche from sympatric shark species (e.g., coastal carcharhinids) and hunt more rapidly via faster swimming for deep-water prey compared to species that permanently inhabit deep depths.

Sedimentary facies controlled biogeochemical process of biotic extinction and turnover across the Cambrian SPICE event

The Steptoean positive carbon isotope excursion (SPICE) event, one of the largest carbon cycle perturbations in the Cambrian, coincides with shallow-shelf-fauna extinction and plankton revolution (critical transition of plankton). The event is globally documented, but biogeochemical responses of these biotic evolutions in varying facies environments are not well understood. Here high-resolution paired δ18Ocarb, δ13Ccarb and δ13Corg datasets from varied paleodepth environments in the Tarim Basin, NW China reveal facies-dependent signatures of the event, with globally synchronous patterns but notable intra-basinal variability. Shallow marine facies record the end-Marjuman extinction with a distinct negative δ13Corg excursion prior to the event, while the transitional facies region marks twice positive δ13C excursions corresponding to an asynchronous plankton revolution from shallow and deep areas during the event. The varying isotope responses are interpreted in the context of primary productivity and redox conditions, with deeper basins recording more 13C enriched signals (i.e., higher δ13C) due to greater organic matter preservation under anoxic conditions, compared to the platform area. The biotic extinction, the planktonic revolution and the interaction of organisms along the shallow to deep marine depth gradient were reflected by the significant isotopic shifts recorded during the event, suggesting depth-dependent biogeochemical processes that shaped marine ecosystems.

Euclid: The rb–M∗ relation as a function of redshiftI. The 5 × 109M⊙ black hole in NGC1272

Core ellipticals, which are massive early-type galaxies with almost constant inner surface brightness profiles, are the result of dry mergers. During these events, a binary black hole (BBH) is formed, destroying the original cuspy central regions of the merging objects and scattering stars that are not on tangential orbits. The size of the emerging core correlates with the mass of the finally merged black hole (BH). Therefore, the determination of the size of the core of massive early-type galaxies provides key insights not only into the mass of the black hole, but also into the origin and evolution of these objects. In this work, we report the first dynamical mass determination of a supermassive black hole (SMBH). To this end, we study the center of NGC 1272 the second most luminous elliptical galaxy in the Perseus cluster, combining the Visible Camera (VIS) photometry coming from the Early Release Observations (EROs) of the Perseus cluster with the Visible Integral-field Replicable Unit Spectrograph (VIRUS) spectroscopic observations at the Hobby-Eberly Telescope (HET). The core of NGC 1272 is detected on the VIS image. Its size is $1 or 0.45 which was determined by fitting PSF-convolved core-S\'ersic and Nuker-law functions. We deproject the surface brightness profile of the galaxy finding that the galaxy is axisymmetric and nearly spherical. The two-dimensional stellar kinematics of the galaxy is measured from the VIRUS spectra by deriving optimally regularized non-parametric line-of-sight velocity distributions. Dynamical models of the galaxy are constructed using our axisymmetric and triaxial Schwarzschild codes. We measure a BH mass of $(5 which is in line with the expectation from the BH $--$r_ b $ correlation, but is eight times larger than predicted by the $M_ BH $--sigma correlation (at $1.8 significance). The core size, rather than the velocity dispersion, allows one to select galaxies harboring the most massive BHs. The spatial resolution, wide area coverage, and depth of the (Wide and Deep) surveys allow us to find cores of passive galaxies that are larger than 2 at a redshift of up to 1.

Influence of tectonic evolution processes on burial, thermal maturation and gas generation histories of the Wufeng-Longmaxi shale in the Sichuan Basin and adjacent areas

The Wufeng-Longmaxi (WL) shale is widely distributed in the Sichuan Basin and adjacent areas in southwest China. The basin experienced multiple-stage complex tectonic movements, whose influences on burial, thermal maturation and gas generation histories in different areas are poorly understood. Based on a detailed study of the denudation stages, strata thickness, and thermal history of the basin, burial and thermal maturation histories of seven wells in different areas were modelled using PetroMod software. Due to the high maturity of the WL shale, a low-maturity Silurian Polish Llandovery shale was used for gold tube closed-system pyrolysis experiments to obtain kinetic parameters for evaluating methane generation history. The Polish shale was selected due to its depositional age, sedimentary environment and organic type, which are similar to the WL shale. The burial history of the WL shale can be divided into five stages: I. Early to Middle Silurian rapid burial; II. Caledonian uplift and denudation; III. Permian to Triassic sustained burial and denudation; IV. sustained burial since the Late Triassic; and V. Late Cretaceous to present sustained uplift and denudation. The thermal maturity of the WL shale in all wells increased with burial depth during stage IV. In addition, high calculated reflectance increments in wells JY1 and N201 during stage III occurred due to the relatively high basal heat flow and deep burial depth, resulting in higher current thermal maturities than in the other wells. The late Permian–Early Triassic and the Middle Jurassic–Early (or Late) Cretaceous were the key methane generation periods for wells JY1 and N201. In contrast, the other five wells had a single methane generation stage, mainly determined by burial and thermal maturation processes. The time of uplift and the amount of denudation during stage V, the current burial depth, the development of faults and fractures, high proportion of retention and the seal capacity of the overlying caprock are key factors for shale gas preservation. Hence, this study will help guide future shale gas development in the Sichuan Basin.

Advances in Spectro-Microscopy Methods and their Applications in the Characterization of Perovskite Materials.

Perovskite materials are promising contenders as the active layer in light-harvesting and light-emitting applications if their long-term stability can be sufficiently increased. Chemical and structural engineering are shown to enhance long-term stability, but the increased complexity of the material system also leads to inhomogeneous functional properties across various length scales. Thus, scanning probe and high-resolution microscopy characterization techniques are needed to reveal the role of local defects and the results promise to act as the foundation for future device improvements. A look at the parameter space: technique-specific sample penetration depth versus probe size highlights a gap in current methods. High spatial resolution combined with a deep penetration depth is not yet achievable. However, multimodal measurement technique may be the key to covering this parameter space. In this perspective, current advanced spectro-microscopy methods which have been applied to perovskite materials are highlighted.

Magmatic initial and saturated water thresholds determine copper endowments: Insights from apatite F-Cl-OH compositions

Magmatic volatiles (H2O, F, Cl), especially water, are critical in the formation of porphyry copper deposit, for its significance as a carrier for metals. However, accurately quantifying the water contents of deep ore-forming magma remain a challenge. Here, we used apatite and forward modelling methods to reconstruct magmatic water evolution histories, with special concern on the control of initial magmatic H2O contents and water saturation threshold to porphyry mineralization. Samples investigated include granitoid rocks and apatite from highly copper-mineralized and barren localities. Generally, our research suggested that both ore-related and ore-barren magma systems are hydrous, the modeled magmatic water contents vary significantly among systems whether mineralized or not, and the major difference lies in the threshold of water saturation (6.0 wt% for barren, and up to 10.0 wt% for highly mineralized). Combined with whole rock geochemistry data (high K2O and Sr/Y contents) and modeling result (high modeled water thresholds), we think the ore-related magmas are stored at deeper depth with higher water solubility. In conclusion, we propose that the level of magmatic water saturation plays a crucial role in the formation of porphyry copper systems. Fertile magma has higher water solubility to which deeper storage depth is a critical contributing factor, and can get significantly water enriched upon saturation.

Practical 6-DoF Manoeuvring Simulation of a BB2 Submarine Near the Free Surface

It is necessary to predict the manoeuvring performance of a submarine accurately at the early design stage for its safe and effective operations. In this paper, the practical 6-DoF simulation models of an X-form stern plane submarine operating near the free surface are proposed. A 1/15 scaled model of ‘BB2 submarine’ is constructed, the captive model tests are performed in a towing tank of Korea Research Institute of Ships and Ocean Engineering (KRISO) at the full-scale depths, 30, 15.4 (snorkel depth), and 4.5 metres (surfaced depth). Resistance and propulsion tests are performed at the deepest depth, 30 metres. The vertical planar motion mechanism (PMM) tests including the forced rolling motions are also carried out at the depth of 30 metres. The horizontal PMM tests are conducted at three kinds of depths, respectively. The depth-varying horizontal plane coefficients in the model are identified, and the coefficients which are little influenced by the depths are treated as the constant values for the practical purpose. Some of velocity coupled terms are approximated by using the added mass coefficients on the assumption that the viscous components are negligible. In addition, the resistance increases, vertical suction forces and moments are measured in the straight-ahead tests with varying the submergence depths. The free surface effects are considered as the exponential function terms in the proposed models. Based on the present tests and the previous studies about the free surface effects on the submerged bodies, it is practically assumed that the free surface effects are exponentially decayed with the depths, and are already negligible when the submergence depth is 30 metres, approximately three times the hull depth. Horizontal and vertical plane manoeuvring motions as well as the neutral flights are simulated with the control plane deflections less than 15 degrees. The present simulations are in good agreements with existing free-running model test results.

Beyond The Usual Suspects: A Challenging Case Of Radix Entomolaris With Endodontic-Periodontal Lesion: A Case Report

The purpose of this case report is to present an unusual endodontic periodontal lesion along with radix entomolaris in tooth 46 in a 31-year-old female patient with intermittent pain and sensitivity to hot and cold stimuli. Clinical examination revealed deep dentinal caries and periodontal pocket depth of 5mm in tooth #46.The radiographic examination revealed an extra distal root with a periapical radiolucency in tooth #46. patient was diagnosed with irreversible pulpitis and chronic apical periodontitis, with secondary periodontal involvement due to an endodontic-periodontal lesion. Non-surgical root canal treatment was performed, followed by canal obturation with resin-based sealer and final restoration with a porcelain fused to metal crown. After a 3-month follow-up, the patient remained asymptomatic, radiographs showed bone reposition, and periodontal probing depth decreased, indicating successful treatment.

Enhanced Depth Control and Stability in Submersible Pylon Inspection Robots Using IMU-Based Extended Kalman Filter and PID Control

The research developed a Submersible Pylon Inspection Robot (SPIR) to clean and inspect underwater structures automatically, facing challenges in stability and depth of operation. Integrating the Inertial Measurement Unit (IMU) with the Extended Kalman Filter (EKF), as well as implementing customized PID controls, aims to improve the accuracy and stability of SPIR in dynamic underwater environments. The results show that the SPIR control system can follow the reference depth at shallow depths well, but has difficulty maintaining stability at deeper depths. The position error graph on the Z-axis shows the initial fluctuation that decreases over time, reflecting the increased calibration. The use of drive motors also shows different working patterns, with some motors active in depth settings and others for stabilization. This study shows that the integration approach of IMU, EKF, and PID control can improve SPIR performance, although further adjustments are required to meet the extreme challenges in underwater environments.

Internal tidal dynamics and associated processes at highly supercritical slopes in Banda Sea: Lessons from the oceanic island of Ambon, eastern Indonesia

Interactions between the deep sea and steep-sloping oceanic islands generate physical processes with potential impacts on sediment resuspension and ocean productivity. While studies have been conducted in the open oceans, those focusing on oceanic islands of the deep Banda Sea in eastern Indonesia are lacking. Here, we present the first observational evidence of vertical mechanisms (i.e. internal tidal reflection, internal hydraulic jumps) at the highly supercritical slope in outer Ambon Bay (OAB) in Ambon Island – an oceanic island in the Banda Sea. A 23-h CTD yoyo experiment combined with ADCP measurements conducted during spring flood and ebb tides demonstrated tidally-varying vertical temperature, salinity and density profiles. During spring flood tide, incoming internal tides were reflected by OAB's highly supercritical slope back to the deep sea with isopycnals and isotherms showing sharp downward plunges (downward vertical velocity = 6.5–8.3 × 10−3 m/s), and the internal tidal amplitude reaching 90–110 m. The reflection during flood tide caused seaward overturning flow at deeper depths despite the prevailing landward flow at the upper layers. During spring ebb tide, internal hydraulic jumps (upward vertical velocity = 6.1–6.48 × 10−3 m/s) occurred to rebound the downward plunges of isopycnals and isotherms as flood tide relaxed with the observed amplitude of internal tides of 90 m. We also observed weakened seaward ebb flow during the isothermal uplifting (when hydraulic jumps occurred), and subsequent intensified landward flow at the end of spring ebb tide indicating strong upslope flow when isotherms reached the maximum shoaling depths. Taken together, the observed vertical mechanisms indicate the conservation of energy at the highly supercritical slope of OAB evident by the comparable vertical velocities. An embedded turbidity-chlorophyll profiler in the CTD reveals that internal tidal activities at the highly supercritical slopes OAB may induce bottom nepheloid layers, and influence ocean productivity by regulating the vertical distribution of phytoplankton biomass.

Anti-inflammatory effectiveness of Peperomia pellucida (L.) Kunth in rats induced with periodontitis

BackgroundPeriodontitis, marked by deep periodontal pocket depth (PPD), facilitates bacterial colonization and inflammation, necessitating adjunctive therapies. Although 0.2 % chlorhexidine (CHX) mouthwash is effective, its side effects have led to the search for alternative treatments. Peperomia pellucida (L.) Kunth, known as Pepper Elder, is a traditional medicinal plant with potential as an adjunctive herbal therapy for periodontitis. ObjectiveThis study aimed to investigate the anti-inflammatory efficacy of Peperomia pellucida extract in rats with induced periodontitis. MethodsA post-test control group design was used in this laboratory experimental study. Four groups of Wistar strain Rattus norvegicus rats were utilized: a Pristine group (without periodontitis), a negative control group (induced periodontitis only), a positive control group (induced periodontitis and administered 0.2 % CHX), and an experimental group (induced periodontitis and administered 2.5 μL of Pepper Elder extract). Each treatment group received daily administration for one week. PPD measurements were taken on days 0, 3, 5, and 7. Blood serum was collected on day 7 for ELISA to measure IL-1β, TNF-α, IL-10, and IL-13 levels. Statistical analysis was performed using the Kruskal-Wallis test with a post hoc LSD and Mann-Whitney test. ResultsThe extract-treated rats showed a decrease in PPD, with significant differences between the extract group and the negative control group (p < 0.05). TNF-α levels in the extract group differed significantly from the negative control group (p < 0.05) but not from the Pristine and positive control groups. IL-1β levels differed significantly only from the negative control group. IL-10 levels were significantly different from both the Pristine and negative control groups, while IL-13 levels differed significantly only from the negative control group. ConclusionPeperomia pellucida (L.) Kunth extract exhibits anti-inflammatory effects in rats with induced periodontitis.

D3L-SLAM: A Comprehensive Hybrid Simultaneous Location and Mapping System with Deep Keypoint, Deep Depth, Deep Pose, and Line Detection

Robust localization and mapping are crucial for autonomous systems, but traditional handcrafted feature-based visual SLAM often struggles in challenging, textureless environments. Additionally, monocular SLAM lacks scale-aware depth perception, making accurate scene scale estimation difficult. To address these issues, we propose D3L-SLAM, a novel monocular SLAM system that integrates deep keypoints, deep depth estimates, deep pose priors, and a line detector. By leveraging deep keypoints, which are more resilient to lighting variations, our system improves the robustness of visual SLAM. We further enhance perception in low-texture areas by incorporating line features in the front-end and mitigate scale degradation with learned depth estimates. Additionally, point-line feature constraints optimize pose estimation and mapping through a tightly coupled point-line bundle adjustment (BA). The learned pose estimates refine the feature matching process during tracking, leading to more accurate localization and mapping. Experimental results on public and self-collected datasets show that D3L-SLAM significantly outperforms both traditional and learning-based visual SLAM methods in localization accuracy.

NIR‐II AIEgens for Infectious Diseases Phototheranostics

AbstractPathogenic infectious diseases have persistently posed significant threats to public health. Phototheranostics, which combines the functions of diagnostic imaging and therapy, presents an extremely promising solution to block the spread of pathogens as well as the outbreak of epidemics owing to its merits of a wide‐spectrum of activity, high controllability, non‐invasiveness, and difficult to acquire resistance. Among multifarious phototheranostic agents, second near‐infrared (NIR‐II, 1000–1700 nm) aggregation‐induced emission luminogens (AIEgens) are notable by virtue of their deep penetration depth, excellent biocompatibility, balanced radiative and nonradiative decay and aggregation‐enhanced theranostic performance, making them an ideal option for combating pathogens. This minireview provides a systematical summary of the latest advancements in NIR‐II AIEgens with emphasis on the molecular design and nanoplatform formulation to fulfill high‐efficiency in treating bacterial and viral pathogens, classified by disease models. Then, the current challenges, potential opportunities, and future research directions are presented to facilitate the further progress of this emerging field.

NIR-II AIEgens for Infectious Diseases Phototheranostics.

Pathogenic infectious diseases have persistently posed significant threats to public health. Phototheranostics, which combines the functions of diagnostic imaging and therapy, presents an extremely promising solution to block the spread of pathogens as well as the outbreak of epidemics owing to its merits of a wide-spectrum of activity, high controllability, non-invasiveness, and difficult to acquire resistance. Among multifarious phototheranostic agents, second near-infrared (NIR-II, 1000-1700 nm) aggregation-induced emission luminogens (AIEgens) are notable by virtue of their deep penetration depth, excellent biocompatibility, balanced radiative and nonradiative decay and aggregation-enhanced theranostic performance, making them an ideal option for combating pathogens. This minireview provides a systematical summary of the latest advancements in NIR-II AIEgens with emphasis on the molecular design and nanoplatform formulation to fulfill high-efficiency in treating bacterial and viral pathogens, classified by disease models. Then, the current challenges, potential opportunities, and future research directions are presented to facilitate the further progress of this emerging field.

Biodegradable ICG-Conjugated Germanium Nanoparticles for In Vivo Near-Infrared Dual-Modality Imaging and Photothermal Therapy.

Theranostics, by integrating diagnosis and therapy on a single platform, enables real-time monitoring of tumors during treatment. To improve the accuracy of tumor diagnosis, the fluorescence and photoacoustic imaging modalities can complement each other to achieve high resolution and a deep penetration depth. Despite the superior performance, the biodegradability of theranostic agents plays a critical role in enhancing nanoparticle excretion and reducing chronic toxicity, which is essential for clinical applications. Herein, we synthesize biocompatible and biodegradable indocyanine green (ICG)-conjugated germanium nanoparticles (GeNPs) and investigate their biodistributions in nude mice and 4T1 tumor models after intravenous injections using near-infrared (NIR) dual-modality fluorescence and photoacoustic imaging. The ICG-conjugated GeNPs have strong NIR absorption due to the NIR-absorbing ICG and Ge in combination, emit strong NIR fluorescence due to the multilayered ICG coatings, and exhibit very low in vitro and in vivo toxicity. After tail vein injections, the ICG-conjugated GeNPs mainly accumulate in the liver and spleen as well as the tumor with the help of the enhanced permeability and retention effect. The tumor's fluorescence signal is much stronger than that of the control group injected with pure ICG solution, as the GeNPs can function as biodegradable carriers for efficiently delivering the ICG molecules to the tumor. Lastly, the ICG-conjugated GeNPs accumulated in the tumor can also be utilized for photothermal treatment under NIR laser irradiation, after which the tumor volume almost diminishes after 14 days. The experimental findings in this work demonstrate that the ICG-conjugated GeNPs are promising theranostic agents with exceptional biodegradability for in vivo NIR dual-modality imaging and photothermal therapy.

Integration of multiple observations for validation of mechanisms of earthquake-triggered groundwater level Anomalies: 2016 Taiwan Meinong earthquake

This study analyzes multi-depth groundwater level data and integrated observation data to validate the previously proposed mechanisms of hydrological anomalies triggered by the 2016 M6.4 Meinong earthquake in Taiwan. The main influence area was northwest of the epicenter, which may be due to the blind fault rupture, intensity distribution, and hydrogeological properties. The step changes in groundwater level do not fit the concept of epicentral distance, static stress–strain theory, or the focal mechanism. The distribution of step changes in groundwater level have a pattern similar to that of horizontal peak ground velocity. The results imply that these changes may be driven by dynamic stress–strain, instead of static stress–strain. The minimum horizontal peak ground velocity and acceleration of the Meinong earthquake, which induced obvious step changes in groundwater level and soil liquefaction, are provided. The pressure dissipation ability of an aquifer (e.g., transmissivity) may affect the persistence of groundwater responses. Four wells located near the surface rupture area, which has cemented or partial cemented geological material, showed an obvious step decrease in the groundwater level at a deep depth and all wells showed an increase in the groundwater level at a shallow depth. These decreases and increases of the groundwater level at different depths have different mechanisms, which are discussed in this study. The integrated observations made during the Meinong earthquake show that ground motion and the hydraulic properties might be important factors in hydrological anomalies. The results of this study are an important reference for further studies on earthquake hydrology.

Characterizing Rock-Breaking Performance of PDC Cutters via Stability Metrics and Energy consumption in FDEM Simulations

As oil production increasingly transitions from shallow to deep formation, the need for efficient PDC cutters to drill through deep hard rock becomes paramount. Currently, there is a lack of effective methods for optimizing cutter shapes and their cutting parameters. This study addresses this gap by developing a rock-breaking mechanism model for PDC cutters and proposing a Stability Index (SI) based on cutting force variations during the cutting process. Using the FDEM method, we simulated the rock-breaking processes of planar, stinger, and machete cutters under various cutting depths and angles. SI and Mechanical Specific Energy (MSE) were employed as evaluation metrics to analyze the rock-breaking characteristics and determine the optimal cutting parameters for each cutter type. The results indicate that at shallow cutting depths, cutting force changes are minimal, predominantly causing plastic damage to the rock, resulting in lower stress and reduced wear on the PDC cutters. Conversely, at greater cutting depths, significant fluctuations in cutting force occur, leading to brittle failure and the generation of large cuttings. This sudden increase in cutting force can accelerate rock breaking but also increases the risk of cutter wear. Our findings suggest that the planar cutter offers stable performance with high cutting force requirements, optimal at a cutting depth of 1.5 mm and an angle of less than 20°. The stinger cutter, requiring lower cutting forces, performs best at a cutting depth of 2 mm and an angle of 20°. The machete cutter exhibits characteristics similar to the stinger cutter at shallow depths and the planar cutter at deeper depths, making it suitable for drilling at a depth of 2 mm and an angle of less than 10°. By balancing SI and MSE, this study provides a comprehensive approach to optimizing PDC cutter performance, enhancing drilling efficiency while minimizing cutter wear.

Microfacies impacts on reservoir heterogeneity of early cretaceous Yamama carbonate reservoir in South Iraq

Detailed well-log interpretations, including gamma-ray, density, neutron, and resistivity, alongside petrographic analysis of 100 samples over 170 m of drill cores, have revealed factors influencing reservoir heterogeneity in the Yamama Formation, Ah’Dimah Oilfield, southern Iraq. The formation comprises four reservoir units (YA-YD) separated by four non-reservoir units (BA-BD). The reservoir units are subdivided into subunits. YB2, YB3, and YC demonstrate the best reservoir quality, while YD2 is water-bearing. Seven microfacies were identified within both reservoir and non-reservoir units, deposited in a shallow carbonate ramp. These include bioclastic wackestone, Lithocodium-Bacinella float/boundstone, peloidal cortoid intraclast grainstone, reefal bioclastic rudstone, bioclastic foraminiferal wacke/packstone, miliolidal pack/grainstone, and spiculitic foraminiferal wackestone. Despite the deep burial depth of the formation (> 4000 m), it maintained good porosity values in most intervals, reaching up to 20%. Early isopachous cement protected porosity and dissolution enhanced porosity, while cementation, compaction, and pyritization reduced it. The reservoir units correlate with depositional environments, being deposited in the shoal area, while non-reservoir units were deposited in lagoon, middle, and outer-ramp settings. The Lithocodium-Bacinella float/boundstone and reefal bioclastic rudstone facies, forming reefal patches and build-ups within the shoal, dominated in YB2 and YC. Targeting these patches northeast of Ah’Dimah Oilfield is promising for field development.

Organic probes for three‐photon fluorescence imaging in NIR‐II window: Design, applications, and perspectives

AbstractThree‐photon fluorescence (3PF) imaging is an emerging technology for imaging deep‐tissue submicroscopic structures by nonlinearly redshifting the excitation wavelength to the second near‐infrared (NIR‐II) window; thus, this approach has great advantages, including deep penetration depth, good spatial resolution, low background, and a high signal‐to‐noise ratio. 3PF imaging has been demonstrated to be a powerful tool for noninvasively visualizing all kinds of deep tissues in recent years. Benefiting from excellent biosecurity and structural controllability, the development of organic 3PF probes is highly important for advancing 3PF imaging in vivo. However, there is no summary of the generalizability of the design and recent progress in organic 3PF probes. Herein, this review introduces the fundamental principle of 3PF imaging and highlights the advantages of 3PF bioimaging. The molecular design of these organic 3PF probes is also summarized based on relative optical indices. Furthermore, different 3PF imaging application scenarios are listed in detail. In the end, the main challenges, significance of probe exploitation, and prospective orientation of organic probes for precise 3PF imaging are proposed and discussed for promoting future applications and clinical translation.