The effects of excessive drilling diagnosis on decay propagation in trees

The effects of excessive drilling into the trunk with an increment borer and drilling resistance measurement device were determined for four trees of three different species (Populus nigra L., Acer pseudoplatanus L., Quercus robur L.). At the test trees with an internal decay it was found that there are two counteracting effects: First, the internal decay slightly enters into the drilling channel, which is locally a negative effect. But, on the other hand, there is the creation of a reaction zone beside the drilling hole enclosing the drilling channel in order to delay efficiently further decay propagation. Furthermore, there is the formation of a barrier zone spacious covering the location of drilling with multiple layers of fungicide tissue. These are two positive effects stopping or delaying the local outgrowth of the internal decay. Far away from the drilling hole the internal decay is not only locally coming out into the sound wall thickness but is also not specially delayed in propagation. So after some years the decay front is everywhere homogenous again, respectively, the spreading central inner decay has caught up with the migrated decay in the drilling channel. For the tree the negative effect of drilling was compensated nearly completely. In addition, it was found that in no case a decay had entered the drilling channels from outside and survived in the outer area of the drill hole.     

Influence of the drilling mud formulation process on the bacterial communities in thermogenic natural gas wells of the Barnett Shale

The Barnett Shale in north central Texas contains natural gas generated by high temperatures (120 to 150°C) during the Mississippian Period (300 to 350 million years ago). In spite of the thermogenic origin of this gas, biogenic sulfide production and microbiologically induced corrosion have been observed at several natural gas wells in this formation. It was hypothesized that microorganisms in drilling muds were responsible for these deleterious effects. Here we collected drilling water and drilling mud samples from seven wells in the Barnett Shale during the drilling process. Using quantitative real-time PCR and microbial enumerations, we show that the addition of mud components to drilling water increased total bacterial numbers, as well as the numbers of culturable aerobic heterotrophs, acid producers, and sulfate reducers. The addition of sterile drilling muds to microcosms that contained drilling water stimulated sulfide production. Pyrosequencing-based phylogenetic surveys of the microbial communities in drilling waters and drilling muds showed a marked transition from typical freshwater communities to less diverse communities dominated by Firmicutes and Gammaproteobacteria. The community shifts observed reflected changes in temperature, pH, oxygen availability, and concentrations of sulfate, sulfonate, and carbon additives associated with the mud formulation process. Finally, several of the phylotypes observed in drilling muds belonged to lineages that were thought to be indigenous to marine and terrestrial fossil fuel formations. Our results suggest a possible alternative exogenous origin of such phylotypes via enrichment and introduction to oil and natural gas reservoirs during the drilling process.     

The post‐Palaeozoic fossil record of drilling predation on lingulide brachiopods

Research on drilling predation, one of the most studied biological interactions in the fossil record, has been concentrated on prey with calcareous skeletons (e.g. molluscs, echinoids, rhynchonelliform brachiopods). Based on a compilation of literature sources and surveys of paleontological collections of the Florida Museum of Natural History and the National Museum of Natural History, we provide a tentative evaluation of the post‐Palaeozoic history of drilling predation on the organophosphatic brachiopods of the family Lingulidae. Despite temporal, geographical and methodological limitations of the data assembled here, the results indicate that lingulide brachiopods have been subject to drilling predation since at least the Eocene. Variation in drilling frequencies at the locality level suggests that lingulides may occasionally experience somewhat elevated predation pressures from drilling organisms. Overall, however, drilling predation on lingulide brachiopods has been infrequent in the Cenozoic and may have been absent in the Mesozoic. The Mesozoic‐to‐Cenozoic increase in drilling frequencies on lingulides is similar to the trends observed in other marine benthic invertebrates and consistent with the hypothesis that predation pressures increased through time in marine ecosystems.     

Drilling in the dorid species Vayssierea cf. elegans (Gastropoda: Nudibranchia): Functional and comparative morphological aspects

The drilling mode of feeding is known from two clades of Gastropoda: Caenogastropoda and Heterobranchia. However, the level of convergence and parallelism or homology among these two lineages is unclear. The morphology of the buccal complex is well studied for drilling caenogastropods, but poorly known for drilling nudibranchs. It is also unclear whether the drilling feeding mechanism is similar between inside gastropods. Accordingly, a comparison between the feeding mechanisms of drilling nudibranchs and caenogastropods can help to understand the evolutional trends inside gastropods. In this study, we redescribe the morphology of the buccal complex of drilling dorid nudibranch Vayssierea cf. elegans, and compare it to that of previous investigations on this species and closely related dorid species. We describe the feeding mechanism of this species based on the obtained morphological and literature data and compare it to the feeding mechanisms described for drilling caenogastropods. The feeding apparatus of Vayssierea cf. elegans corresponds to the general morphology of the dorid buccal complex; that is, it has a similar arrangement of the buccal musculature and pattern of radular morphology. However, there are also adaptations to the drilling feeding mode similar to those found in Caenogastropoda: that is, specialized dissolving glands and lateral teeth with elongated pointed cusps; and even Sacoglossa: the specialized muscle for sucking. The feeding process of Vayssierea cf. elegans includes the same two stages as those described for drilling caenogastropods: (a) the boring stage, which is provided by mechanical and chemical activity, and (b) the swallowing stage.     

Investigation of the potential for microbial contamination of deep granitic aquifers during drilling using 16S rRNA gene sequencing and culturing methods

Total number of bacteria, viable counts of aerobic and anaerobic heterotrophic bacteria and 16S rRNA gene diversity were investigated during drilling of three boreholes in the walls of the Äspö hard rock laboratory tunnel, at depths ranging from 380 to 446 m below sea level. Water samples were taken from the drill water source, the drilling equipment and from the drilled boreholes. The drill water was kept under nitrogen atmosphere and all equipment was steam cleaned before the start of a new drilling. Total and viable counts of bacteria in the drilled boreholes were several orders of magnitude lower than in the samples from the drilling equipment, except for sulphate reducing bacteria. A total of 158 16S rRNA genes that were cloned from the drill water source, the drilling equipment and the drilled boreholes were partially sequenced. The drilled boreholes generally had a 16S rRNA diversity that differed from what was found in samples from the drilling equipment. Several of the sequences obtained could be identified on genus level as one of the genera Acinetobacter, Methylophilus, Pseudomonas and Shewanella. In conclusion, the tubing used for drill water supply constituted a source of bacterial contamination to the rest of the drilling equipment and the boreholes. The results show, using molecular and culturing methods, that although large numbers of contaminating bacteria were introduced to the boreholes during drilling, they did not establish in the borehole groundwater at detectable levels.     

不同发育期诸氏鲻虾虎鱼对钻井液的敏感性比较

目的筛选试验鱼适宜急性毒性试验的发育期。方法将诸氏鲻虾虎鱼早期仔鱼、中期仔鱼、晚期仔鱼、稚鱼、幼鱼及成鱼暴露于一定浓度的钻井液中,比较钻井液对不同发育期诸氏鲻虾虎鱼的急性毒性。结果早期仔鱼48 h LC50为157 mg/L,中期仔鱼48 h LC50大于500 mg/L;中期仔鱼96 h LC50为79 mg/L,晚期仔鱼96h LC50为625 mg/L,稚鱼、幼鱼、成鱼96 h LC50显著大于500 mg/L;卤虫无节幼体96 h LC50为105 mg/L;不同发育期诸氏鲻虾虎鱼对钻井液的敏感性顺序为：早期仔鱼〉中期仔鱼〉晚期仔鱼〉稚、幼、成鱼。结论诸氏鲻虾虎鱼的早期仔鱼适用于海洋污染物急性毒性评价。     

颅骨自动钻孔技术探析

头骨钻孔为脑部微创手术的重要步骤,现有钻孔设备多采朋手动方式,钻孔设备没有任何判断钻穿的装置,钻穿骨头后停止钻进完全靠医生的经验来实现。介绍了国内外该领域的研究现状与存在问题,提出了一种颅骨钻穿自动停刀的判断方法,提出了颅骨自动钻孔技术未来发展的趋势。     

Comparing predatory drillholes to taphonomic damage from simulated wave action on a modern gastropod

Marine drilling predation, in which the predator bores a hole through shelled invertebrate prey, plays a role in the structure of benthic communities. As drilling often leaves the prey shell otherwise undamaged, the resulting holes are also an excellent proxy for drilling predation pressure in the fossil record. Considering that a large number of predation studies focus on drilling predation in the fossil record, it is crucial that we are able to distinguish true drilling predation from taphonomy. The purpose of this study is to determine damage on Olivella biplicata shells, drilled by naticid gastropods, is distinguishable from taphonomically produced damage to these shells. In addition, the potential for preferential breakage due to either the presence or whether absence of a drillhole was investigated. Drilled and non-drilled O. biplicata shells were tumbled to simulate wave action and were checked at intervals to record accumulated damage. Drilled and non-drilled shells do not show a significant difference in damage accumulated while undergoing simulated wave action. Taphonomic damage is unlikely to be mistaken for drilling damage, due to the jagged, irregular appearance of taphonomically produced holes.     

Post-Drilling Changes in Seabed Landscape and Megabenthos in a Deep-Sea Hydrothermal System,the Iheya North Field,Okinawa Trough

There has been an increasing interest in seafloor exploitation such as mineral mining in deep-sea hydrothermal fields, but the environmental impact of anthropogenic disturbance to the seafloor is poorly known. In this study, the effect of such anthropogenic disturbance by scientific drilling operations (IODP Expedition 331) on seabed landscape and megafaunal habitation was surveyed for over 3 years using remotely operated vehicle video observation in a deep-sea hydrothermal field, the Iheya North field, in the Okinawa Trough. We focused on observations from a particular drilling site (Site C0014) where the most dynamic change of landscape and megafaunal habitation was observed among the drilling sites of IODP Exp. 331. No visible hydrothermal fluid discharge had been observed at the sedimentary seafloor at Site C0014, where Calyptogena clam colonies were known for more than 10 years, before the drilling event. After drilling commenced, the original Calyptogena colonies were completely buried by the drilling deposits. Several months after the drilling, diffusing high-temperature hydrothermal fluid began to discharge from the sedimentary subseafloor in the area of over 20 m from the drill holes, ‘artificially’ creating a new hydrothermal vent habitat. Widespread microbial mats developed on the seafloor with the diffusing hydrothermal fluids and the galatheid crab Shinkaia crosnieri endemic to vents dominated the new vent community. The previously soft, sedimentary seafloor was hardened probably due to barite/gypsum mineralization or silicification, becoming rough and undulated with many fissures after the drilling operation. Although the effects of the drilling operation on seabed landscape and megafaunal composition are probably confined to an area of maximally 30 m from the drill holes, the newly established hydrothermal vent ecosystem has already lasted 2 years and is like to continue to exist until the fluid discharge ceases and thus the ecosystem in the area has been altered for long-term.     

Drilling under threat: An experimental assessment of the drilling behavior of Nucella lamellosa in the presence of a predator

Using the drilling muricid, Nucella lamellosa (Gmelin 1791) and its prey, the mussel Mytilus trossulus (Gould 1850), the impact of a secondary predator, the crab Cancer gracilis, on drilling was investigated experimentally. The frequency of incomplete holes was compared under two conditions: (1) when the gastropod's natural predator, C. gracilis, was present and (2) when it was absent. The results indicate that the presence of a secondary predator can affect drilling activity, leading to a significant increase in the frequency of incomplete drill holes. The introduction of a secondary predator can also decrease the overall drilling frequency. The size distributions of completely and incompletely drilled mussels suggest that in the presence of the secondary predator the decision by the gastropod to either abandon or continue drilling its prey might be influenced by how much time it has already invested into drilling or the size of the prey item. These results are important for the ecological and evolutionary implications of incomplete drill holes frequencies, especially with regard for their use as proxies for evolutionary prey improvement.     

Techniques for Contamination Assessment During Drilling for Terrestrial Subsurface Sediments

Details about the procedures for drilling a ca. 150 m long drill core in a terrestrial setting under contamination controlled conditions are presented. Different to previous studies we only used commercially available drilling equipment to reduce the cost of operation significantly. The goals were (1) to minimize, (2) to monitor and, if possible, to quantify the contamination of the recovered sediments, and (3) to identify the different sources of contamination. Both the potential contamination of the sample material by surface microorganisms and non-indigenous material was assessed. To estimate the infiltration of drill mud into the core, fluorescent microspheres, having about half the size as microorganisms, were added to the mud. The drilling technique used was mud rotary drilling. With the exception of the very beginning of the drilling operations, the drill mud was devoid of any allochthonous hydrocarbons potentially derived from the drilling equipment or drill additives, and its biomarker composition reflected the varying organo-facies that were penetrated. Due to the lack of allochthonous hydrocarbons in the drill mud, its infiltration into the sediment cannot be traced by organic geochemical biomarker analysis. Microspheres proved to be a sensitive tool for the assessment of infiltration of drill mud into the core. The concentration of microspheres in the drill mud decreased continuously during the drilling, most probably caused by seepage of mud through leaks and attachment of spheres to the surface scum in the mud pit. Microscopic enumeration of the microspheres showed great variability in the depth of penetration of mud into the core, apparently unaffected of lithology. The sampling of the core material in the laboratory was carried out inside an anaerobic chamber. Several techniques for subsampling were used, according to sediment properties. The overall results indicate that, if strict contamination control protocols are employed, it is possible to recover uncontaminated samples at reasonable cost with commercially available drilling equipment.     

Crop monitoring to assess the risk of slug damage to winter wheat in the United Kingdom

The percentage of winter wheat seeds killed by slugs was measured, together with various risk factors, at 93 sites throughout the UK from 1987 to 1990. Estimates of slug populations at each site were obtained from traps baited with methiocarb pellets. The peak number of slugs trapped during the period from July until just before cultivation accounted for 26% of the variability in seed damage, more than any other single risk factor. A combined function of the number of slugs trapped at drilling and the percentage of fine soil aggregates in the seed-bed accounted for 21% of the variability in seed damage. Both (i) the peak number of slugs trapped before drilling, and (ii) the combined function of number of slugs trapped at drilling and the percentage of fine soil aggregates in the seed-bed, have potential for identifying fields with a negligible risk of slug damage to wheat seeds. However, further research is needed to improve the accuracy of forecasting slug damage. In particular, other forms of trap should be tested for their potential use in providing more accurate estimates of slug numbers and biomass at drilling, and techniques of assessing seed-bed conditions should be improved. The percentage of seedlings grazed by slugs was correlated with the numbers of slugs trapped before drilling, at drilling and after crop emergence.     

Parameters affecting mechanical and thermal responses in bone drilling: A review

Surgical bone drilling is performed variously to correct bone fractures, install prosthetics, or for therapeutic treatment. The primary concern in bone drilling is to extract donor bone sections and create receiving holes without damaging the bone tissue either mechanically or thermally. We review current results from experimental and theoretical studies to investigate the parameters related to such effects. This leads to a comprehensive understanding of the mechanical and thermal aspects of bone drilling to reduce their unwanted complications. This review examines the important bone-drilling parameters of bone structure, drill-bit geometry, operating conditions, and material evacuation, and considers the current techniques used in bone drilling. We then analyze the associated mechanical and thermal effects and their contributions to bone-drilling performance. In this review, we identify a favorable range for each parameter to reduce unwanted complications due to mechanical or thermal effects.     

High frequency of drill holes in brachiopods from the Pliocene of Algeria and its ecological implications

The fossil record holds a wealth of ecological data, including data on biotic interactions. For example, holes in the skeletons of invertebrates produced by drilling activities of their enemies are widely used for exploring the intensity of such interactions through time because they are common and easily distinguished from non-biotic holes or holes produced by other types of interactions. Such drill holes have been described in numerous studies of Palaeozoic brachiopods but rarely in those focusing on brachiopods of the post-Palaeozoic, a striking pattern given that in the late Mesozoic and Cenozoic drilling gastropods diversified and frequencies of drilled molluscs increased dramatically. During the past several years, however, drilled brachiopods were reported in several studies of the Mesozoic and Cenozoic, suggesting that this phenomenon may be more common than has been previously assumed. Here we report on drilled brachiopods from a Pliocene locality in Algeria where 90 of 261 (34.5%) specimens of Megerlia truncata show evidence of predatory drilling. These data confirm that Cenozoic drilling frequencies of brachiopods may be locally high and, when taken together with other published data, that drilling frequencies are highly heterogeneous in space and time.     

Biodegradation of Petroleum Hydrocarbons in a Soil Polluted Sample by Oil-Based Drilling Cuttings

Microbial degradation of hydrocarbons in soils polluted by oil-based drilling mud and cuttings has been investigated by static methods such as composting or biopiling. Bioremediation of polluted soils by oil-based drilling cuttings through a slurry bioreactor has not previously been reported. The main aim of this work is to monitor hydrocarbon biodegradation in slurry of drilling cuttings and unpolluted soils and the effects of nutrients on it. Indigenous, bacterial-mixed culture isolated from a polluted soil by drilling cuttings adapted to drilling mud concentrations up to 15% (v/v) was done during a 15-month program. The total petroleum hydrocarbons’ (TPHs) removal efficiency in C/N/P 100/5/1 ratio was 90.5 and 79.85% under experimental and control conditions, respectively. The microbial count on the first day, 15 × 10⁷ CFUg^?1, reached 20 × 10⁹ CFUg^?1on the twenty-first day at experimental conditions. The TPH removal efficiency in C/N/P 100/10/2 was 92.5 and 82.25% at experiment and control, respectively. Increasing nitrogen and phosphorous amount couldn't increase microbial count in comparison with C/N/P ratio 100/5/1. The measured biomass contents and microbial counts in experiments were significantly higher than the control and confirmed hydrocarbons’ biodegradation during the time. Results showed that slurry bioreactors could accelerate the biodegradation of TPHs and reduce remediation time in soil polluted by oil-based drilling cuttings.     

Modeling and experimentation of bone drilling forces

Prediction and control of bone drilling forces are critical to the success of many orthopaedic operations. Uncontrolled and large forces can cause drill-bit breakage, drill breakthrough, excessive heat generation, and mechanical damage to the bone. This paper presents a mechanistic model for prediction of thrust forces and torques experienced during bone drilling. The model incorporates the radially varying drill-bit geometry and cutting conditions analytically, while capturing the material and friction properties empirically through a specific energy formulation. The forces from the chisel edge are modeled by considering the indentation process that occurs in the vicinity of the drill-bit axis. A procedure is outlined to calibrate the specific energies, where only a small number of calibration experiments are required for a wide range of drilling conditions and drill-bit geometry. The calibration parameters for the cortical portions of bovine tibia are identified through drilling tests. Subsequently, a series of validation tests are conducted under different feed rates and spindle speeds. The thrust forces and torques were observed to vary considerably between bones from different animals. The forces from the model were seen to match well with those from the experimentation within the inherent variations from the bone characteristics. The model can be used to select favorable drilling conditions, to assist in robotic surgeries, and to design optimal orthopaedic drill bits.     

Evaluation of deep subsurface sampling procedures using serendipitous microbial contaminants as tracer organisms

Surface microbiological investigations are critically dependent on the procedures used to collect samples for study. It can be difficult to distinguish between indigenous organisms and those encountered as contaminants during the drilling process. We found that coliform bacteria contaminated drilling mud slurries. These bacteria proved useful as tracer organisms in evaluating the degree of microbial contamination accidentally encountered while drilling for subterranean samples. While these organisms were found in high numbers in both the circulating muds and in the mud reservoir, few subsurface samples harbored conforms. Subsurface slurries did not inhibit the growth of a known coliform inoculum. These results indicate that the methods used to collect and field‐process cores from Atlantic coastal plain sediments were sufficient to prevent a large degree of bacterial contamination in most samples. The microflora in drilling fluids did not quantitatively or qualitatively account for the number and diversity of bacteria in subsurface samples. We conclude that a large and viable bacterial community is present in deep regions of the terrestrial subsurface.     

Fertilization of zona-drilled mouse oocytes treated with a monoclonal antibody to the zona glycoprotein, ZP3

Opening a small aperture in the zona pellucida of mouse oocytes by using micromanipulation and a stream of acidified Tyrode's solution (zona drilling) improved the efficiency of in vitro fertilization at low sperm concentrations without adversely affecting development to the blastocyst stage. Zona drilling also permitted in vitro fertilization and development when sperm penetration through the zona was blocked by a monoclonal antibody to the protein core of the zona glycoprotein, ZP3. These results provide a direct demonstration that sperm entry occurs through the aperture and also suggest that zona drilling of human oocytes may offer a therapeutic approach when autoantibodies to the zona pellucida are suspected as a cause of infertility.     

Naticid gastropod predation in the Gatun Formation (late Middle Miocene), Panama: preliminary assessment

Understanding predator-prey interactions is an important component of community studies, both present and past. Patterns of naticid predation in a fossil molluscan assemblage were studied by examination of drilling frequencies in a series of samples collected at three sites of the Gatun Formation (late Middle Miocene), Panama. Overall drilling intensities were relatively low (18 %) and were not correlated with abundance. Turritellids, turrids, and terebrids (making up to 11 % of the studied fauna) were the most consumed, representing almost 29 % of the total prey. Especially important were turritellids representing over 20 % of the total consumed prey. Albeit abundant (54 % of the studied fauna), columbellids, cerithiids, and marginellids showed low drilling intensities (8.2–10.4 %). Naticids were the major predators. Con-familial drilling among naticids is high and did not seem to be related to absence of preferred prey. Consistent with other studies, these data indicate that predators demonstrate high prey selectivity.     

羟基磷灰石义眼台植入联合一期钛钉打孔术的效果研究

目的：探讨国产医用钛钉系统联合改良羟基磷灰石义眼台钛钉打孔术的手术效果。方法：选择32只健康家兔并将其分两组,在球内容摘除术后分别行单纯义眼台植入及义眼台植入联合一期钛钉打孔术,于2、4、6、12w时每组分别处死4只家兔,观察和评价家兔对钛钉的生物耐受性及HA植入物的血管化过程。以动物实验为基础,对87例患者行羟基磷灰石义眼台一期植入联合钛钉打孔术,随访12个月,观察其手术效果及与此术式相关的并发症,总结分析国产医用钛钉系统联合改良羟基磷灰石义眼台钛钉打孔术的手术效果及优点。结果：动物实验显示：一期钛钉植入术未发生钛钉移位、排斥,扫描电镜结果表明：2、4、6、12w时两组HA血管化过程无显著差异,6w时钛钉周围1mm范围内与其完全对应的环行区域内血管化程度没有显著差异。临床实验显示：改良术式与二期打孔术相比,义眼片活动度显著提高（P〈0．01）,差异有统计学意义（P〈0．05）。两组术后肉芽肿的发生率比较无统计学差异（P〉0．05）。结论：一期植入钛钉生物相容性好,改良术式临床效果佳,术后并发症少。