Insertion Hole Research Articles

The Channel Branches & Network Channels on the Tianhui Lacquered Meridian Figurine — Taking the Heart-Regulated Channel as an Example

Abstract: Along with the surge of unearthed medical literature and cultural relics in recent years, the network of channels in the system of medical channels (meridians) during the early Western Han dynasty have become much clearer gradually. Among them, the increasing number of channel branches, network channels and needle insertion holes (acupoints) is an important feature of the development of classical channel medicine during the Western Han dynasty. This is not only a reflection of the expanding requirements of the theoretical system of the main trunk channels, but also an inevitable result of the continuous enrichment and accumulation of clinical experience. This article integrates the information about channel branches, network channels, inscriptions, dots and further relics on the Tianhui (天回) Lacquered Meridian Figurine to compare the unearthed literature of the channel genre with the transmitted classical literature about acupuncture. The "Heart-Regulated Channel" in Medical Manuscripts on Bamboo Slips from Tianhui (《天回医简》) serves as an example to explain the occurrence, development and changes of the channel branches and network channels in the early system of medical channels.

SHIELD: Skull-shaped hemispheric implants enabling large-scale electrophysiology datasets in the mouse brain

To understand the neural basis of behavior, it is essential to measure spiking dynamics across many interacting brain regions. Although new technologies, such as Neuropixels probes, facilitate multi-regional recordings, significant surgical and procedural hurdles remain for these experiments to achieve their full potential. Here, we describe skull-shaped hemispheric implants enabling large-scale electrophysiology datasets (SHIELD). These 3D-printed skull-replacement implants feature customizable insertion holes, allowing dozens of cortical and subcortical structures to be recorded in a single mouse using repeated multi-probe insertions over many days. We demonstrate the procedure's high success rate, biocompatibility, lack of adverse effects on behavior, and compatibility with imaging and optogenetics. To showcase SHIELD's scientific utility, we use multi-probe recordings to reveal novel insights into how alpha rhythms organize spiking activity across visual and sensorimotor networks. Overall, this method enables powerful, large-scale electrophysiological experiments for the study of distributed neural computation.

Impact of osteosclerosis on cervical pedicle screw insertion using preoperative CT-based navigation.

Preoperative computed tomography (CT)-based navigation is used for cervical pedicle screw (CPS) insertion to mitigate the risk of spinal cord and vertebral artery injury. In vertebrae with osteosclerosis due to degeneration or other factors, however, probing may not proceed easily, with difficulty creating the CPS insertion hole. This study investigated the impact of osteosclerosis on the accuracy of CPS insertion. A total of 138 patients with CPS inserted at the C3-C7 level using preoperative CT navigation were retrospectively analyzed. Pre- and postoperative CT was employed to investigate screw position and Hounsfield unit (HU) values at the lateral mass to evaluate the degree of osteosclerosis in the CPS insertion pathway. Among 561 CPS insertions, the Grade 3 perforation rate was 1.8%, and the Grade 2 or higher perforation rate was 8.0%. When comparing insertions with and without CPS perforation, HU values were significantly higher in the perforation group (578 ± 191 vs. 318 ± 191, p < 0.01). The frequency of CPS insertion into the mid-cervical spine was also significantly greater in the perforation group (68.9% vs. 62.5%, p < 0.01). Logistic regression analysis revealed that a high HU value at the lateral mass (odds ratio 1.09, 95% confidence interval: 1.07-1.11, p < 0.01) was a significant independent factor associated with CPS deviation. The screw perforation rate of Grade 2 or higher in CPS insertion using preoperative CT-based navigation was 8.0%. Since osteosclerosis was an independent factor related to CPS deviation, additional care may be required during insertion into affected vertebrae.

197 Pre-clinical Ex-vivo Study of a 3D Neuronavigation With a Neurosurgical Microrobot

INTRODUCTION: Access to deep brain structures for diagnostic and therapeutic purposes remains a challenge for neurosurgeons. To solve this obstacle, we are developing a micro-robot with the technology to navigate the brain with 3D curved trajectories that will open a new range of possibilities in the neurosurgical world (tumor identification, treatment of epileptic foci, DBS, targeted therapies, fenestration of membranes). The microrobot is tracked and navigated with a transcranial ultrasound system. METHODS: 10 cadaveric studies were performed using 4 adult swine and 6 human subjects using micro-robot models with diameters of 4.5 mm and 2.9 mm. The microrobotic base for injection and ultrasound tracking of the microrobot (CAP) was placed on the skull at the insertion hole. The micro-robot was remotely controlled, and the surgeries were performed in a hybrid operating room with 3D fluoroscopy, allowing us to validate the surgery feasibility and evaluate the accuracy of the transcranial tracking. RESULTS: 20 burr holes were performed with holes ranging from 4-9 mm in diameter. The microrobot was inserted successfully infall cases. The navigation was effective with straight or curved trajectories in 18 cases and the targeted points were reached in 16 cases. We observed a mean 3D tracking accuracy of 1.49mm with a S.D. of 0.58 mm, demonstrating a millimetric tracking accuracy, similar to the best stereotaxy performance. CONCLUSIONS: These results are a world first, proving the feasibility of intracerebral parenchymal microrobotic neuro-navigation with a millimetric ultrasound transcranial tracking. Future tests will allow testing new prototypes of 1.8mm diameter enabling clinical translation.

A Lateral Fracture Line Affects Femoral Trochanteric Fracture Instability and Swing Motion of the Intramedullary Nail: A Biomechanical Study.

An unstable trochanteric femoral fracture is a serious injury, with a 1-year mortality rate of 5.4% to 24.9%, for which there is currently no standard treatment method. The lag screw insertion site is one of the primary contact areas between the cortical bone and an intramedullary nail. We hypothesized that a posterolateral fracture causes intramedullary nail instability when the posterolateral fracture line interferes with lag screw insertion. The purpose of the present study was to investigate the effect of posterolateral fracture line morphology on intramedullary nail stability by simulating unstable trochanteric femoral fractures with a posterolateral fracture fragment. Eighteen custom-made synthetic osteoporotic bone samples were used in the present study. Nine samples had a posterolateral fracture line interfering with the lag screw insertion hole (Fracture A), and the other 9 had a fracture line 10 mm away from the hole (Fracture B). Cyclic loading (750 N) was applied to the femoral head 1,500 times. Movement of the end cap attached to the intramedullary nail was recorded. The amplitudes of motion in the coronal plane (coronal swing motion), sagittal plane (sagittal swing motion), and axial plane (total swing motion) were evaluated. The change in the neck-shaft angle was evaluated on photographs that were made before and after the test. Medial cortical displacement was measured before and after the test. Two Fracture-A samples were excluded because the amplitude of sagittal swing motion was too large. The mean values for coronal, sagittal, and total swing motion were 1.13 ± 0.28 mm and 0.51 ± 0.09 mm (p < 0.001), 0.50 ± 0.12 mm and 0.46 ± 0.09 mm (p = 0.46), and 1.24 ± 0.24 mm and 0.69 ± 0.11 mm (p < 0.001) for Fractures A and B, respectively. The mean neck-shaft angle change was -8.29° ± 2.69° and -3.56° ± 2.35° for Fractures A and B, respectively (p = 0.002). The mean displacement of the medial cortex was 0.38 ± 1.12 mm and 0.12 ± 0.37 mm for Fractures A and B, respectively (p = 0.57). This study showed that an unstable trochanteric femoral fracture with a posterolateral fracture line that interferes with the lag screw insertion holes is a risk factor for increased intramedullary nail instability.

Reinforcing structures proliferated around a titanium implant inserted into the femur of female rabbits, in a hole smaller than the screw core

One of the basic conditions for the clinical success of osseo-integrated implants is implant stability (Albrektsson and Zarb, 1993). It comprises two components, the primary stability that should be ensured at the time of insertion and the secondary stability, which gradually replaces the primary stability. The primary stability is ensured by the direct contact between the implant surface and that of the bone walls of the insertion hole. Secondary stability begins with the first position of new bone on the implant surface. The aim of the present study was to verify the reinforcing structures proliferated around the titanium implant inserted into the femur of 5 adult female rabbits, in a groove smaller than the screw core diameter. The results suggested that inserting the titanium implant into a hole with a smaller diameter than the screw core produces excessive pressure on the bone, which is felt up to a distance from the bone-implant interface. Consequently, mechanical strength of the bone is decreasing and proliferating bone consolidation formations appears on both periosteum and endosteum areas. Additionally, it was observed that newly proliferated bone extends laterally from the interface to a great distance, causing thickening of the bone wall. The observed structures were represented by branched bone trabeculae and bony protrusions into the medullary cavity, together with bone reshuffling processes with the appearance of numerous osteons, most of which are present at the level of the wall opposite the insertion area.

Insertion Torque (IT) and Implant Stability Quotient (ISQ) Assessment in Dental Implants with and without Healing Chambers: A Polyurethane In Vitro Study

Primary Stability (PS) depends on different factors, such as bone structure (quality and density), implant characteristics (macro and micro), and the relationship between thread shape and implant insertion hole size. PS is crucial for the prognosis and success of dental implants. The use of healing chambers, which create empty spaces between the implant and peri-implant bone, helps reduce the risk of compressive bone necrosis. High Insertion Torque (IT) values could potentially lead to the deterioration of the implant-abutment connection. However, the optimal implant macro-structure and IT values remain unknown. In this study, implants with healing chambers (Test) and without (Control) were inserted into polyurethane blocks with densities of 10, 20, 30, and 40 pounds per cubic foot (PCF). In blocks with densities of 30 and 40 PCF, Control implants had significantly higher IT values than Test implants. Additionally, Control implants exhibited significantly higher Removal Torque (RT) values than Test implants, but only in the 30 PCF density block (p &lt; 0.0001). However, no differences were found between the implants in the 10, 20, and 40 PCF density blocks. Similarly, no significant differences were observed in the Implant Stability Quotient (ISQ) values between the Test and Control implants. The results of the present study confirm that adding healing chambers to the macro-structure of dental implants can significantly reduce IT values without affecting ISQ values. This suggests the potential for avoiding compression and damage to peri-implant bone while maintaining consistent levels of PS.

Patterns of basidiocarp growth in oak mazegill (Daedalea quercina, Polyporales) revealed by experimental and natural perturbations

ABSTRACT In Polyporales, the pore field immediately behind the basidiocarp margin may configure the hymenophore. Basidiocarp growth is not restricted to the margin, however. Here, the importance of the pore field was assessed from two years’ of observations on naturally occurring oak mazegill (Daedalea quercina, Polyporales) basidiocarps and tested by experimental perturbations in natural habitats. Oak mazegill was chosen because the formed hymenophore has a unique and stable combination of poroid and lamellate features. Whether the pore field is required for basidiocarp growth was tested in 10 basidiocarps in which one side was resected. New growth was observed in six basidiocarps, and it occurred equally from the cut hymenophore and the intact pore field. New formation of hymenophore and pileus even occurred in seven out of 10 basidiocarps that had the entire pore field resected. Whether the hymenophore is configured permanently was tested on 54 basidiocarps on 10 trunks that were turned upside down. A new hymenophore grew through the old pileus, often far from the pore field, and its hymenophore configuration was invariably poroid despite the old hymenophore had lamellate features. In 48 experimentally banded basidiocarps, new hymenophore grew in the insertion hole of the band despite this being far from the pore field. The banded basidiocarps grew at an average rate of 5 mm per year. In conclusion, the capacity to configure the hymenophore is not confined to the pore field and it could be broadly present in the basidiocarp, possibly due to ubiquitous hyphal totipotency.

Design shaped hole inserts by simulating and analysing the high-speed filling posture of maize seed particles

Design shaped hole inserts by simulating and analysing the high-speed filling posture of maize seed particles

Overlapping Esophagojejunostomy Using a Linear Stapler in Laparoscopic Total or Proximal Gastrectomy.

Background: Performing an intracorporeal esophagojejunostomy during laparoscopic-assisted total or proximal gastrectomy is challenging. We developed an ingenious method of overlapping esophagojejunostomy using a linear stapler to avoid stapler-related intraoperative complications. Methods: Following lymph node dissection, the esophagus was transected anterior-posteriorly. A linear stapler was used to divide the jejunum ∼20 cm distal to the Treitz ligament. A small enterotomy was then created 5 cm distal to the elevated jejunal stump to insert the linear stapler cartridge. An electronic knife was used to make a full-thickness incision, with the tip of the nasogastric tube (NGT) pressed against the posterior wall of the esophageal stump as a guide. Full-thickness sutures were placed on both the anterior and posterior walls of the entry hole in the esophageal stump to prevent the anvil fork from being misinserted into the submucosal layer of the esophagus. The thread on the posterior wall was guided through the port to the outside of the abdominal cavity, where the linear stapler was inserted to perform the side-to-side anastomosis. A 45-mm cartridge fork and an anvil fork were inserted into the elevated jejunum and esophageal stump entry holes, respectively, following which the esophageal stump was gently grasped. The thread on the posterior wall side was pulled from outside the abdominal cavity through the port. This step is necessary to close the gap between the esophageal and jejunal walls. After confirming that the anvil fork was not misinserted into the submucosal layer of the esophagus and that there was no gap between the esophagus and the elevated jejunum, the linear stapler was fired to create the anastomosis. The insertion hole was closed with hand-sewn sutures or linear staples to complete the esophagojejunostomy. Results: Eleven patients underwent this procedure with no anastomotic complications. Conclusions: This method enables us to perform an easier and more stable esophagojejunostomy.

Magnetic Resonance-Guided Stereotaxy for Infusions to the Pig Brain.

The overall goal of this procedure is to perform stereotaxy in the pig brain with real-time magnetic resonance (MR) visualization guidance to provide precise infusions. The subject was positioned prone in the MR bore for optimal access to the top of the skull with the torso raised, the neck flexed, and the head inclined downward. Two anchor pins anchored on the bilateral zygoma held the head steady using the head holder. A magnetic resonance imaging (MRI) flex-coil was placed rostrally across the head holder so that the skull was accessible for the intervention procedure. A planning grid placed on the scalp was used to determine the appropriate entry point of the cannula. The stereotactic frame was secured and aligned iteratively through software projection until the projected radial error was less than 0.5 mm. A hand drill was used to create a burr hole for insertion of the cannula. A gadolinium-enhanced co-infusion was used to visualize the infusion of a cell suspension. Repeated T1-weighted MRI scans were registered in real time during the agent delivery process to visualize the volume of gadolinium distribution. MRI-guided stereotaxy allows for precise and controlled infusion into the pig brain, with concurrent monitoring of cannula insertion accuracy and determination of the agent volume of distribution.

Evidence of correlated incommensurate structural and magnetic order in highly oxygen-doped layered nickelate Nd2NiO4.23

$\mathrm{Nd}{}_{2}\mathrm{NiO}{}_{4+\ensuremath{\delta}}$ is a nonstoichiometric oxide, crystallizing in the Ruddlesden-Popper-type framework and exhibiting a wide range of oxygen nonstoichiometry $\ensuremath{\delta}$ with a complex structural phase diagram. Excess oxygen atoms insert holes, directly influencing the Ni valence state and associated electronic structure. We report here the existence of a correlated incommensurate structural and antiferromagnetic order below $T{}_{N}\phantom{\rule{4pt}{0ex}}\ensuremath{\approx}$ 150 K in highly oxygen-doped $\mathrm{Nd}{}_{2}\mathrm{NiO}{}_{4+\ensuremath{\delta}}$ with $\ensuremath{\delta} \ensuremath{\approx}$ 0.23. The crystal and magnetic structures are investigated by polarized and unpolarized single-crystal neutron diffraction studies together with synchrotron x-ray powder diffraction and macroscopic magnetization measurements. Due to the long-range ordering of excess oxygen atoms, the real structure of the compound is incommensurately modulated, represented by $\mathbf{Q}{}_{n}=\ifmmode\pm\else\textpm\fi{}0.813{\mathbf{a}}^{*}\ifmmode\pm\else\textpm\fi{}0.519{\mathbf{b}}^{*}$ wave vectors. The antiferromagnetic order is characterized by the presence of incommensurate Bragg peaks of type ($h\phantom{\rule{4pt}{0ex}}\ifmmode\pm\else\textpm\fi{}\phantom{\rule{4pt}{0ex}}\ensuremath{\varepsilon}$, 0, $l$/2), with $h$ and $l$ being odd-integer numbers and the magnetic incommensurability $\ensuremath{\varepsilon}\ensuremath{\approx}$ 0.36. The in-plane magnetic correlation length is found to be $\ensuremath{\xi}{}_{ab}$ = 184(1) \AA{} but is significantly reduced along the $c$ axis to $\ensuremath{\xi}{}_{c}$ = 39(2) \AA{}, indicating the quasi-two-dimensional nature of the antiferromagnetic correlations. Our study indicates that the excess oxygen atoms nevertheless strongly enhance the magnetic correlations between the ${\mathrm{NiO}}_{2}$ planes, resulting in a doubling of the magnetic unit cell along the $c$ axis. In contrast to $\mathrm{Nd}{}_{2}\mathrm{NiO}{}_{4.1}$, in which the incommensurate periodicity of oxygen and magnetic ordering was found to be identical, the structural and electronic orderings in heavily oxygen-doped ${\mathrm{Nd}}_{2}{\mathrm{NiO}}_{4.23}$ show two independent modulation vectors. Our study thus unravels a strong correlation between structural and electronic orderings in the highly oxygen-doped $\mathrm{Ln}{}_{2}\mathrm{NiO}{}_{4+\ensuremath{\delta}}$ system.

Endoscopic submucosal dissection (esd) training sessions on ex-vivo porcine models

Endoscopic Submucosal Dissection (ESD) is a technique for removing lesions in the gastro-intestinal tract. It involves precise cutting into the submucosal layer, allowing for the lesion to be removed in one piece, and has been shown to have a high curative resection rate [1]. It is a technically challenging endoscopy technique that requires experience and practice. As one of the common complications from ESD is perforation [2], training on ex-vivo models is becoming popular with 84% of surveyed centres in the UK requiring Endoscopists to complete a number of ESDs on animal models before progressing to train on patients [3]. While training was accessible at other centres, this was infrequent and less accessible. Sessions were created at the hospital training centre. This was done using decommissioned endoscopy stacks and endoscopes, so that these were always available and designated for ex-vivo use only. The animal model was a porcine oesophagus, stomach, and start of duodenum prepared in a box with a hole for endoscope insertion. The duodenum was clamped to ensure inflation would be possible. The days ran from 0830-1530 with a drop-in option. After 7 sessions were run over 5 months, a survey was sent out to the 8 people that had participated to assess the benefits of the service (including faculty doing the training and trainees). 8 responses (100%) were collected. 62% (n=5) of responders had used ex-vivo models before. 83.3% of trainees (n=5) said they had come to our hospital specifically to train in ESD technique. Responders attended between 1 and 10 sessions at our centre. All trainees and faculty said they found the training extremely beneficial and that they thought the ex-vivo model work well the way it was set up. All responders said they would recommend the sessions to a colleague. All trainees said that training with an experienced Endoscopist was more beneficial than training alone. Suggestions for improvement included a more consistent timetable of when they could access sessions, more accessibility and wider range of endoscopy kit, and involving the wider nursing team in the sessions. The ex-vivo ESD training sessions were well received by both faculty and trainees and were said to be very beneficial to their training. We will therefore be putting on more of these sessions, taking into account the suggestion for a regular accessible timetable. 1. Ahmed Y, Othman M. EMR/ESD: techniques, complications, and evidence. Current Gastroenterology Reports. 2020;22(8):1–2. 2. Kim SG, Hwang JH. How to decrease the risk of perforation in endoscopic submucosal dissection (ESD). Techniques in Gastrointestinal Endoscopy. 2019;21(2):99–103. 3. Küttner-Magalhães R, Pimentel-Nunes P, Araújo-Martins M, Libânio D, Borges-Canha M, Marcos-Pinto R, Koch AD, Dinis-Ribeiro M. Endoscopic submucosal dissection (ESD): how do Western endoscopists value animal models?. Scandinavian Journal of Gastroenterology. 2021;56(4):492–7.

A Simple and Safe T-Shaped Esophagojejunostomy for Laparoscopic Total Gastrectomy

BackgroundIn laparoscopic total gastrectomy, esophago-jejunal anastomosis is still considered a complicated procedure, even though laparoscopic surgery has become widespread. Esophagojejunostomy leakage can be fatal and adversely affect postoperative cancer treatment. The leakage rate has been reported to be 2.4–5.5%, and a safer and more reliable technique needs to be established. In this multi-media article, we describe the technique of laparoscopic esophagojejunostomy using a simple and safe T-shaped esophagojejunostomy. MethodsWe performed laparoscopic total gastrectomy with ante-colic Roux-en-Y reconstruction using a T-shaped anastomosis. First, insertion holes are made on the right side of the esophageal stump and the opposite side of the mesentery of the lift-up jejunal stump. Second, a linear stapler is inserted into each insertion hole, and a 40–45-mm V-shaped esophageal jejunal anastomosis is performed. Third, three temporary sutures are added for closing the common edge. Finally, a second stapling is used to close the entry hole and resect the esophageal stump. ResultsWe performed this procedure in 35 patients between May 2016 and December 2018. The median duration of surgery was 338 min (range, 248–542 min) and median bleeding was 20 mL (range, 0–240 mL). There were no esophagojejunostomy-related complications higher than Clavien-Dindo grade II. Additionally, no postoperative stenosis occurred during the follow-up period (median: 48 months, range: 4–68 months). ConclusionConsidering the present results, T-shapedesophago-jejunal anastomosis is a simple and safe procedure and a promising laparoscopic total gastrectomy option.

Pregnancy diagnosis in goats (Capra hircus) using barium chloride and progesterone-based kit in Bangladesh

The study was conducted to develop a technique for early diagnosis of pregnancy in goats from July 2016 to June 2017. About 100 goats of different age groups were randomly selected for the trial and goats were categorized under four groups according to their gestation lengths (0.5 to 1 month, &gt;1 to 1.5 months, &gt;1.5 to 2 months and &gt;2 to 2.5 months). Blood from jugular vein and morning urine samples were collected from four groups and brought to the laboratory, and serum was separated from the clotted blood. Then 1%, 1.5% and 2% barium chloride solution were prepared and test was done by using 1 ml barium chloride of each concentration mixing with 1 ml of urine sample, and allowed for 5 and 10 minutes for interpretation. Presence of precipitation was interpreted as negative for pregnancy and absence of precipitation was interpreted as positive for pregnancy. For each blood sample, 3-5 drops of serum was added in each sample insertion hole of the Bovipreg kit and 5 minutes was allowed to observe the presence of one or two red line in the kit. One red line was interpreted as negative pregnancy and two red lines were interpreted as positive pregnancy. In our study 1% barium chloride, showed 93.5% accuracy, whereas 1.5% barium chloride provided 92% accuracy for the goats having 0.5 to 1 month of gestation. In case of 2% barium chloride, the highest accuracy was 91.5% for the goats having &gt;1 to 1.5 month of gestation. Conversely, the accuracy for progesterone-based early pregnancy diagnostic kit was 96.5%. Therefore, 1% barium chloride can be utilized for the diagnosis of pregnancy in goats. Asian J. Med. Biol. Res. 2022, 8 (1), 42-46

Вплив конструкторсько-технологічних чинників на довговічність вставного твердосплавного породоруйнівного оснащення шарошок тришарошкових бурових доліт

Aim. In the study learning trial was made to make a mathematical model of the assembling process in connections " tungsten carbide insert cutter - cone", while the methods of mathematical statistics were applied. This makes it possible to determine the parameters of the distribution of the closing link. Accordingly, the tension is determined by samples of constituent links. For this purpose, the amount of tension was investigated. Tension affects the change in stress, which characterizes the accuracy of the assembly on the strength of the connection " tungsten carbide insert cutter - cone ". Depending on the magnitude of the insert pressing force, it is customary to estimate the tension in the connection. Method. The analysis of tungsten carbide insert cutter and holes in the layers of bit established that the size errors of the component links of dimensional chains are distributed according to laws that they are similar to the normal law of the distribution of random variables. The test was carried out according to the criteria of Pearson and Kolmogorov Results. The increase in pressing force with an increase in tension is due to an increase in elastic deformation both in the cemented layer and in the core layers of the rolling-cutter row. The extreme nature of the dependence of the pressing force on the amount of tension for the connection " tungsten carbide insert cutter - cone " has been established. This dependence, as a characteristic of the strength in the connection, can be used to design technological pressing operations for roller cone bits steels with different strength indicators. Scientific novelty. a mathematical model of the assembling process of connections " tungsten carbide insert cutter - cone " was made. It makes it possible to determine the parameters of the distribution of the closing link - tension, based on the samples of the component links. The established dependencies make it possible to reasonably and most accurately approach the formation of selective groups of teeth and the marking of holes for them. Practical significance. The appointment of tensions, the value of which exceeds the value of the extreme point, causes the occurrence of unfavorable plastic deformation or destruction of the layers of the shell (which are conjugated along the height of the shank of the insert cutter). They also result to the occurrence of irrational stresses in the body of the tungsten carbide insert cutter. It was established that the tension values have a greater influence on the force of pressing carbide teeth into the holes of roller cone bits steel 9310H (USA), when its hardness value is Rockwell hardness 59-60 compared to Rockwell hardness 48-50. Within the limits of the studied tension values, this dependence is linear.

An Inexpensive In Vitro Blood-Feeding System for Wild Aedes albopictus (Diptera: Culicidae)

An Inexpensive <i>In Vitro</i> Blood-Feeding System for Wild <i>Aedes albopictus</i> (Diptera: Culicidae)

The effects of locking inserts and overtorque on the mechanical properties of a large fragment locking compression plate

PurposeThe study was to determine the effect of locking hole inserts and their insertion torque on the fatigue life of a large fragment Locking Compression Plate (LCP) under bending forces.MethodsFatigue strength of the LCP was examined using cyclic three-point bend testing at 80% yield strength of the construct. Locking hole inserts were used in 2, 4, and 6-hole of a 12-hole plate to simulate three different working lengths. Within each working length, plates were tested without locking inserts serving as the control group. In the experimental groups, inserts were tightened to manufacturer recommendations (4 Nm) and using overtorque (8 Nm).ResultsSignificantly fewer cycles to failure were observed in control groups versus the locking hole insert groups for all working lengths (2-hole: 4 Nm p = 0.003, 8 Nm p = 0.003; 4-hole: 4 Nm p = 0.02, 8 Nm p < 0.001; 6-hole: 4 Nm p = 0.004, 8 Nm p < 0.001). There was a statistically significant increase in fatigue strength when using overtorque in the 4-hole (p = 0.04) and 6-hole (p = 0.01) defect groups. This was not shown in the 2-hole defect group (p = 0.99).ConclusionsBy placing locking inserts in the empty locking regions of Combi holes along the working length, the number of cycles to failure was increased. Tightening inserts to twice the recommended insertion torque further increased cycles to failure in longer working length models. A longer fatigue life has the potential to decease the incidence of plate failure especially in the setting of delayed union due to poor intrinsic healing capacity, fractures in the geriatric population, osteoporosis and periprosthetic fractures.

Effect of Using Coolant on the Formation of Microcracks, Burr and Delamination in Bone Drilling Process

Direct approach for bone fracture treatment usually involves restoring the fractured parts to their initial position and immobilizing them with plates, screws and wires. This approach needs a bone surgery drilling to produce hole for screw insertion. But this drilling process causes mechanical damages, i.e microcracks, burr formation and delamination, that can reduce the stability of the fixation. One of the ways to minimize it is by using coolant. Moreover, it is noted that bone has anisotropic microstucture. The object of this study is to understand the effect of coolant on mechanical damages that occur in bone drilling and to understand the effect of microstructure difference on microcracks that occur in the drilled walls holes. Adult bovine bones and adult goat bones were used in this study as the specimens to represent differences in cortical bone microstructure. Five consecutive holes from the distal to the proximal in each specimen were generated using manual hand-drill (spindle speed (n) = 1000 rpm; drill bit (d) = 4 mm diameter) with the use of coolant as variation. The drilling holes then stained and observed using a microscope. As the result, it was found that the use of coolant can significantly reduce the drilling temperature. Microcracks, burr formation and delamination were found to be quite large in the drilling holes without coolant. However, there is no microcrack found in the drilling holes with coolant, there is only a small number of burr formation was found. In addition, it was found that the differences in bone microstructure affect the number and length of microcracks that occur in the wall of the hole. It can be concluded from this study that the application of coolant is very effective to reduce the drilling temperature and enhancing the quality of the hole generated by bone drilling and the higher the density of osteon in cortical bone, the easier the microcrack to initiate and propagate.

A Coupled-Cavity Resonator Technique for Simultaneous Sensing of Dielectric Load and Position of Continuous Material Streams

An electromagnetic coupled-cavity resonator equipped with permanent insertion holes and designed to sense continuous dielectric material streams through the resonator is presented. The resonating structure comprises a pair of pill-box-shaped cylindrical cavities mutually coupled to each other through an aperture-loaded metal sheet of finite thickness. The input and output insertion holes in the top and bottom lids of the cavity structure form a channel for the flow of dielectric samples under test. The arrangement of aperture-coupled cavity sections results in antisymmetric and symmetric field distributions with split resonances. The resonating antisymmetric field is primarily utilized to detect dielectric load variations of the sample stream, similar to the commonly practiced permittivity based measurements in TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">010</sub> cavities. The additional resonance mode with the symmetric field distribution is more sensitive to position offsets of the sample in its concentric flow along the axis. Due to the added resonance, the arrangement provides for 2-D sensing of dielectric specimens under test (dielectric load variation and position offset) and improved accuracy can, thus, be achieved. The working principle of the coupled-cavity technique is analyzed qualitatively by numerical computations. The technique is validated by measuring samples of commercially available cotton fibers with a realized prototype.