Distance Of Opening Research Articles

Effect of Horizontal Distance of Web Opening on the Ultimate Load Carrying Capacity of Castellated Steel Beams by an Analytical Approach

Objectives: The primary objective of this current research is to determine the ideal horizontal spacing for hexagonal web openings and their maximum load-bearing capacity through Finite Element Analysis (FEA). Methods: The ISMB150 was implemented as a cross-sectional profile to fabricate distinct models of castellated beams with heights of 225 mm. The height of the web openings remained constant at 150 mm for the castellated beam model. The entire analysis is being done on ANSYS 19.2. Findings: The analysis has revealed that, for castellated beams with shallower depths, an optimal horizontal spacing of 44.9 mm for the web openings yields an ultimate load-bearing capacity of 144.26 KN. The results of castellated beams are measured in terms of ultimate load-carrying capacity, span-to-deflection ratio, load density, failure location, span-to-beam depth ratio, and the ratio of horizontal distance of opening-to-opening depth. Novelty: This research contributes analytical findings for the ideal horizontal distance of hexagonal web opening through maximum load-bearing capacity. Castellated beams have gained immense popularity within the structural engineering community today due to their visually appealing design featuring a variety of web-opening shapes. The primary objective of this current research is to determine the ideal horizontal spacing for hexagonal web openings and their maximum load-bearing capacity through Finite Element Analysis (FEA). The ISMB150 was implemented as a cross-sectional profile to fabricate distinct models of castellated beams with heights of 225 mm. The height of the web openings remained constant at 150 mm for the castellated beam model. The analysis has revealed that, for castellated beams with shallower depths, an optimal horizontal spacing of 44.9 mm for the web openings yields an ultimate load-bearing capacity of 144.26 KN. The results of castellated beams are measured in terms of ultimate load-carrying capacity, span-to-deflection ratio, load density, failure location, span-to-beam depth ratio, and the ratio of horizontal distance of opening-to-opening depth. This research contributes valuable insights into optimizing the design of castellated beams for enhanced structural performance. Further exploration and validation could provide additional refinements and applications in structural engineering. Keywords: Horizontal distance of web opening, Number of openings, Ultimate load carrying capacity, Failure modes, ANSYS, Castellated beams

Hydraulic performance of bottom intake velocity caps using PIV and OpenFOAM methods

The objective of this investigation is to obtain a more profound understanding of the effective parameters of the velocity caps for bottom intake systems, utilizing particle image velocimetry (PIV) and OpenFOAM. Observations indicate a higher probability of surface vortex formation in square types compared to circular ones, with the vortex being formed downstream of the caps. Additionally, the flow pattern reveals that the flow whirls in a more favorable path into the circular caps as opposed to the square ones. Through both experimental and numerical comparisons of three shapes (rhombus, square, and circle), it becomes evident that the circular type outperforms the other types in terms of discharges through the intake, showing an improvement of about 8%. The results indicate that flow depth and height of the velocity caps are positively effective parameters for the flow rate, with respective influences of 90% and 30%. In contrast, the interaction between the flow and caps intensifies with an increase in the distance of the intake opening from the bed, which plays a negative influence on the flow rate. Enhancing the number of blades in caps proves to be the optimal approach for generating a smoother flow with minimal impact on the flow rate. Numerical simulations show a 50% reduction in cap height leads to a significant 33% decrease in flow rate. Additionally, rotating the square cap by 45° into a rhombus aligned with the flow direction results in a 7% discharge flow rate increase.

Evaluation of subarcuate canal on CT images in the perspective of clinical basis.

The aim of our study to contribute to the field of morphometrics by including measurements of the SAC and SAF and their distances from surrounding structures, particularly for surgeons involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery. Although there is limited information in the literature regarding the role of the subarcuate fossa (SAF) and subarcuate canal (SAC), it has been suggested that the SAC may be a potential pathway for infection from the middle ear to the posterior cranial fossa, and cerebellar abscesses may have this origin. For the images of our study, computerized tomography images of 118 individuals (59 females and 59 males) between the ages of 18-65 who applied to Bayındır Health Group. The width of the cranial opening of the subarcuate canal was determined as 44 ± 0.54mm, width of the labyrinth opening of the subarcuate canal was determined as 60 ± 0.42mm, Length of the subarcuate canal was determined as 8.79 ± 2.31mm, width of the subarcuate canal was determined as 5.54 ± 1.75mm, and depth of subarcuate fossa was determined as 1.67 ± 0.69mm. The distance of the cranial opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/C) was measured as 5.33 ± 1.81mm, The distance of the labyrinth opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/L) was measured as 3.90 ± .98mm, length of the petrous part of the temporal bone medial to the anterior semicircular canal measured from the apex to the SSCD (PLM) was measured as 33.56 ± 0.42mm. No statistically significant differences were found between the right and left sides. The morphometric measurements obtained in this study can provide useful information for neurosurgeons, neurotologist and otolaryngologists involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery, and for patients undergoing cochlear implant planning with a retrofacial approach.

Limiting the available pneumatic power in a U-OWC

A fixed oscillating water column is a hollow structure open to the sea at its submerged part. The water column motion alternately compresses and decompresses the enclosed air above the inner free surface, which drives a self-rectifying air turbine. In 2003, Boccotti proposed the so-called U-OWC having in view the integration into breakwaters. In this configuration, the inner water is connected to the sea by a U-shaped duct whose opening faces upwards rather than sideways or downwards. This allows the OWC length to be extended (and the resonance frequency reduced) without placing the opening too deeply submerged where wave energy is attenuated by distance to the free-surface. An advantage of OWC converters is the capability to control or dissipate the excess energy available to the power take-off system in excessively energetic sea states. This is in general done by limiting the air turbine torque by controlling a by-pass air valve or a valve in series with the turbine. What is proposed here is to take advantage of the water column configuration to limit the energy absorbed from the waves in the more energetic sea states. This requires the tidal amplitude to be small as occurs in coastal areas like the Mediterranean Sea. The distance of the OWC opening to the mid-sea-level should be chosen such that, in the more energetic sea states, that opening is left uncovered by the troughs of the higher waves. This introduces a limitation to the energy absorbed in the more energetic sea states. This paper reports experiments with a 1:40th-scale U-OWC in a wave flume. The results show that limitations to the capture width ratio occurs in the more energetic wave systems.

An experimental study on flame characteristic of spill fire plumes for atypical openings under external sideward wind

The evolution of flame height and horizontal extending distance of the facade with atypical openings (circular and triangular) under external sideward wind is experimentally studied with a reduced-scale compartment model in this paper. The results show that: When the external sideward wind is high and reaches a certain degree, the flame horizontal extending distance will be greater than the flame height, indicating that the flame will be more likely to ignite adjacent rooms on the same floor in this case. (1) The flame height of circular and triangular openings has a linear relationship with sideward wind speed (Uw); (2) The flame horizontal extending distance of circular and triangular opening is nonlinear to the sideward wind speed (Uw); (3) Based on previous studies, a non-dimensional correlation model is constructed to predict the flame height and horizontal extending distance of circular and triangular openings.

Cyclic behavior of metallic damper connected reinforced concrete beam-column joint with an opening in slab

The study proposes a solution of constructing the inevitable rectangular opening in the reinforced concrete (RC) slab upon the metallic damper for the RC beam-column frame to alleviate the adverse effect of the slab for the system compared to the designed bare frame joint. To systematically understand the cyclic behavior of the system, a quasi-static test is conducted on two half-scale specimens, and a parametric study is carried out to explore the effects of the rectangular opening of the RC slab along with the top and bottom flanges of the damper on the hysteretic responses of the system. Test results show that the positive and negative bearing capacities of the system are asymmetric because the centroid shifts upward from the middle of the metallic damper and RC beam. Although the intervention of opening in RC slab for the dog-bone damper connected RC joint is hard to mitigate the additional stiffness and bearing capacity from the slab to the system, such application could restrain the out-of-plane instability of the dog-bone damper by about 21.74% and improve both loading capacity degradation and energy dissipation degradation of the system. Furthermore, numerical results confirm that the distance of opening from the RC slab significantly decreases the depth of the neutral axis of the RC beam with the slab so that the bearing capacity and initial stiffness of the system improve by about 26.47% and 27.88%, respectively, as the distance of the opening to the damper reduced from 0 mm to 60 mm. Moreover, benefitting from the significant influence on the depth of the neutral axis, the bottom flange of the dog-bone damper, especially the flange width and weakened depth of the damper, has a significant improvement on the hysteretic responses of the system.

Investigation of Behavior of Flat Slab with Openings Adjacent to Column of Different Shapes Using CSI-Safe

It is necessary in building to pass pipes and ducts through slab to accommodate essential public services, such as gas pipeline, water supply, and computer networking. However, presence of opening abrupt the path of load to column. This will increase effect of critical forces like moments, deflection, and punching shear. This paper represents numerical analysis and studies the behavior of different types of flat slabs having different types of openings for serviceability and collapse states. The numerical analysis includes group A and group B. Group A and group B are further subdivided into five parts of models with no opening, square opening, circular opening at varying distance of opening from the face column, square opening, and circular opening at the center of slab. This study is conducted to know the behavior of different type of flat slabs. As per analytical result, various conclusion and recommendation are proposed in the study.

The effect of unilateral chewing habit on interincisal distance of maximum mouth opening

One of the causes of temporomandibular disorder (TMD), which is a bad habit of chewing on one side. The occurrence of TMD can be characterized by limited mouth opening of less than 40 mm. Maximum mouth opening distance can be influenced by gender, age, weight, and height. This study is intended to determine the interincisal distance of maximum mouth opening in unilateral chewing habit. By using descriptive observational study with a purposive sampling technique, it was obtained of 25 subjects, students from the Faculty of Dentistry, Mahasaraswati Denpasar University. Data collection was carried out by using a sliding caliper direct to measure the distance of interincisal when open the mouth. The results showed that 10 men (40%) had an average maximum mouth opening of 42.6 mm, 15 women (60%) had an average maximum mouth opening of 39.6 mm, 5 people (20%) with a body weight of 41-50 kg had the lowest average maximum mouth opening of 37.4 mm, 4 people (16%) with a body weight of 81-90 kg had the highest maximum mouth opening of 45.5 mm, 2 people (8%) with a body height of 151-160 cm had the lowest maximum mouth opening of 36.5 mm, 8 people (32%) with a body height of 171-180 cm had the highest maximum mouth opening of 42.3 mm and 25 people (100%) had a maximum mouth opening of 40.8 mm. It was con-cluded that there are 48% (12 people) subjects have an average maximum mouth opening distance with a limited category of 36.3 mm and 52% (13 people) subjects have an average maximum mouth opening distance with a normal category of 45 mm.

Parametric study of reduced web section of beam to column welded connection with castellated beam having hexagonal openings and subjected to cyclic loading

In this paper, a finite element (FE) analysis is carried out on a beam to column welded connections with multiple hexagonal web openings. The openings are distributed along the length of the beam which is subjected to cyclic loading protocol proposed by the SAC and FEMA 350 (2000). This study focuses on the interaction of the connections from columns to the perforated beam and mobilization of stresses. Two parameters were addressed: the distance from the face of the column (S), and the web opening spacing (So) including closely spaced opening. The study revealed that the design of mostly controlled reduced web section (RWS) connections should be fundamentally based on the distance of the first opening from the face of the column. Three values of the distance (S) are presented (200 mm, 350mm, and 520 mm). A model with an ideal distance (S) of 350 mm has resulted in an ultimate rotation of 0.039649 rad, which is less than other models, in which rotations were 0.049386 rad and 0.050000 rad, respectively.

The complexity of cryptoglandular fistula-in-ano can be predicted by the distance of the external opening to the anal verge; implications for preoperative imaging?

Many surgeons believe that the distance from the external opening to the anal verge (DEOAV) predicts the complexity of a cryptoglandular fistulas-in-ano and, therefore, predicts the need for additional imaging. However, there is no evidence to support this. The primary aim of this study was to determine if DEOAV can predict the complexity of a fistula. Secondary aims were clinical outcome and identification of those patients that might not benefit from preoperative imaging. All patients having surgery for cryptoglandular fistula-in-ano between January 2014 and December 2016 were evaluated. Preoperative imaging was used to classify fistulas as simple or complex. The DEAOV was measured preoperatively and was divided into categories ≤ 1cm, 1-2cm, or > 2cm. The relationship between the DEOAV and complexity of the fistula was investigated. Clinical outcome was recorded and a group of patients that might not benefit from preoperative imaging was identified. A total of 103 patients [m:f = 65:38, median age 47 (range 19-79) years] were included. Magnetic resonance imaging identified 39 simple and 64 complex fistulas. The percentage of simple fistula was 88% in fistulas with DEAOV ≤ 1cm, 48% in DEAOV 1-2cm and 38% in > 2cm. There was a significant difference between the complexity of the fistula and the distance to the anal verge (p < 0.001). The overall healing rate was 88%. The complexity of perianal fistula depends on the DEAOV. We propose that preoperative imaging should be performed in fistulas with external opening > 1cm from the anal verge.

Experimental study on beam-to-column connections with reduced beam section against progressive collapse

Steel frame structures with ordinary weld connections often suffer from brittle fractures; to mitigate this issue, measures have been taken to integrate plastic hinges and improve the ductility of the steel connections. A new reduced beam section (RBS) connection, consisting of radius cuts in the beam flanges and circular openings in the beam webs, is proposed to allow for more ductile connections. RBS connections may increase structural deflection and crack width in the steel frame structure under large deformations. Therefore, it is extremely important to consider the bearing capacity and progressive collapse resistance of steel frame structures with RBS connections. In this study, nine different specimens with double-span frames were constructed and tested under a central column removal scenario: one without an RBS (RBS0), one with flange reductions (RBS1), and seven with web and flange reductions (RBS2). The mechanical behaviours of the different specimens were determined, including their failure modes, vertical force-deformation responses, and contribution of catenary action to resist progressive collapse. The results indicated that the RBS0 specimen with brittle failure did not effectively resist progressive collapse. RBS1 exhibited superior ductility and resistance compared to RBS0; however, its resistance to progressive collapse after cracking required further improvement. RBS2 with web openings formed an arch structure to dissipate energy through continuous deformations. Further, two important factors in RBS2 that influenced its mechanical properties were the diameter and the distance of the web opening, which were related to the development of arching and catenary action.

An Automatic Sliding Doors Using RFID and Arduino

The door is an important component in a building as security. It is used as access in and out of a room. People in the modern era now want everyday life that is completely automated, so that the work can be done easily without wasting energy and can shorten the time. Along with the rapid development, the need for effectiveness and efficiency is prioritized in various fields. The purpose of this paper is to design an automatic sliding door that only detects one Radio Frequency Identification (RFID) card to open and close. The use of RFID systems can strengthen the security level of building access. This study uses a data processing method in the form of an ID number generated from a tag. Specifications in the discussion of the results in this study include a motor that uses a 12-volt DC motor, a maximum door weight of 5 kg, can only detect one RFID to open and close the door, and the sliding door used is one door. The results of system testing are obtained to open a door that is without load, and the door can move 14 cm from the distance of the door hole so that it opens. Doors with a load of 1-1.5 kg also move 14 cm from the distance of the door opening when open. Doors with a load of 2-3 kg only move 12.5-9.5 cm from the distance of the door so that it opens. When the door gets heavier 3.5-4 kg, the door moves only 7.5-3 cm from the distance the door hole remains closed.

Effects of openings on the punching shear strength of reinforced concrete slabs

In recent years, the application of reinforced concrete (RC) flat slabs has dramatically increased due to their functional and economic advantages. The exhibition of higher stress at the slab-column connections causes failure, and the punching shear is most likely the governing failure mode for these structures. Besides, the existence of opening positioned close to the column intensifies the vulnerability to punching shear failure of slabs. The current research aims to study the behavior of RC slab-column connections under vertical loads as well as to investigate the effects of openings on the punching shear strength of RC slabs. For this purpose, the finite element (FE) modeling is used to investigate the effects of openings varying in size and location on the punching shear stress of the connections. In the first step, an FE model is developed and validated by an experimental specimen of a slab-column connection from available research. In the second stage of the study, 8 interior connections and 8 edge connections are analyzed under incremental vertical load. Each connection has one opening with the dimensions of 150 × 150 mm and 250 × 250 mm located 0, 75, 150, and 300 mm far from the column in a parallel position while a connection without opening is considered in each case as a reference. Numerical results demonstrate that near-column openings cause a remarkable increase in the shear stress around the slab-column connections. Furthermore, a significant increase in shear stress around the openings is observed by increasing the dimensions of the opening and reducing the distance of opening from the column.

Comparison of three flap designs on postoperative complication after third molar surgery

Introduction: Third molar surgery can cause post-operative complications to the patient due to the presence of wound from the incision. The study aimed to compare modified triangular (triangular reverse) flap with triangular and envelope flap on postoperative complications by the measurements on post-surgical swelling, trismus, pain scale, wound dehiscence and the occurrence of alveolar osteitis.Methods: Study design using a single-blind randomized clinical trial. Each treatment group consisted of 10 patients. An assessment was performed on day 1, 7 and 14 after surgery. The swelling was measured using different anatomical points, and trismus was measured using the distance of inter-incisal opening. The occurrence of dehiscence was measured from the width of the incision line. Alveolar osteitis and pain scale was observed.Results: The results of one way ANOVA (p&gt;0.05) shows there was no difference between treatment groups both for swelling and mouth opening, but there was a difference between treatment groups for dehiscence on days 7 and 14. The results of the Post Hoc test show that flap envelope differs from the other flap design, whereas triangular and triangular reverse flap showed no difference. Friedman test results (p&gt;0.05) showed no difference in VAS score. There was no alveolar osteitis occurred in each treatment group during postoperative control. Kruskal Wallis test (p&gt;0.05) showed that there was no difference of VAS score between treatment group during post-operative control.Conclusion: The triangular reverse flap design may decrease the occurrence of postoperative complication after mandibular third molar surgery.Â

Anatomical Considerations of the Endonasal Transsphenoidal Approach

The sellar contents are separated from the sphenoidal sinus by a tiny sheath of bone that compris es the sellar floor, making the transsphenoidal approach the most used surgical route to intrasellar lesions. The transsphenoidal approach can be initiated in three different ways: 1) cutting the mucosa over the alveolar part of maxilla (sublabial transsphenoidal), 2) cutting along the anterior nasal mucosa adjacent to the columella (transeptal transsphenoidal), and 3) cutting the mucosa over the sphenoidal rostrum (endonasal transsphenoidal). Each cavernous sinus has four dural walls. The lateral, superior and posterior walls are composed of endosteal and periosteal dura leaflets. Unlike the other dural walls, the medial wall is formed of a single, thin dural sheath, an anatomical fact that help explains the lateral expansion of a pituitary adenoma. In the center, the diaphragm sellae has an opening through which the infundibulum courses, linking the pituitary gland to the floor of the third ventricle. The morphology of this opening is quite variable among individuals. On average, the anteroposterior distance of the diaphragm opening was 7.26 mm + 1.99 mm, varying from 3.4 mm up to 10.7 mm. The lateral distance of the diaphragm opening was 7.33 mm + 2.79 mm, varying from 2.8 mm up to 14.1 mm.

Morphology and morphometry of lacrimal drainage system in relation to bony landmarks in Caucasian adults: a cadaveric study.

The objective of this study is to examine the morphometry of the lacrimal drainage system with reference to bony landmarks in the vicinity. Twenty midsaggitalized heads obtained from sixteen preserved cadavers were studied. Measurements involved detailed morphometry of anterior and posterior lacrimal crests, bony lacrimal sac fossa, entrance and length of the bony nasolacrimal duct (NLD), attachment of Horner's muscle, and characteristics of the inferior meatal opening of the NLD. The mean lengths of anterior and posterior lacrimal crests were 16.3 and 12.5mm, respectively. At the midpoint of the posterior lacrimal crest, Horner's muscle was found to be attached at a mean of 1.3mm posterior to the crest. The mean dimensions of the bony lacrimal sac fossa at superior, mid and inferior levels were 6.5, 8.7, and 5.9mm, respectively. The mean contribution of the lacrimal bone to the lacrimal sac fossa was 56.2%. The mean anteroposterior and transverse diameters of the entrance of the bony NLD were 5.7 and 4.7mm, respectively. The most common type of NLD opening in the inferior meatus was that of "vertical sulcus" (70%, 14/20). The mean distance of the NLD opening from the anterior nasal spine and Limen nasi were 22.2 and 18.9mm, respectively. This study provides useful anatomical and positional relationship of bony lacrimal landmarks and nasolacrimal duct in Caucasian adults.

In Response

We read the letter by Liang et al1 with intense interest for which, in addition to their insightful comments, we thank them. The anatomical and physiological mechanisms underlying difficult laryngoscopy remain poorly understood. Mandibular condylar mobility, mouth opening, and angle of mouth opening may be influenced by one another2 and may have influence on laryngoscopy.3,4 However, the most dominant factor among the 3 remains undetermined. As Liang et al have deduced, with the same angle of mouth opening, the larger condylar translation results in a smaller mouth opening. However, whether the angles are equal during this process has yet to be ascertained. The occurrence and degree of extra condylar translation during laryngoscopy remain unknown. In addition, whether condylar translations remain the same when the mouth is maximally opened, or lower jaw protruded (without mouth opening), or during laryngoscopy has yet to be determined. We conducted an observational study to address these questions. The mouth opening and the angles of mouth opening of 10 volunteers were measured under the following conditions: (i) with the lower jaw actively withdrawn and the mouth opened; and (ii) with the mouth maximally opened (Figure). Condylar translations were measured when the mouth was in a maximally opened position and when the lower jaw was protruded (without the mouth opening). We also observed 20 patients and measured their mouth opening when their mouths were opened voluntarily to the maximum and when they were undergoing laryngoscopy. We asked the volunteers to protrude their lower jaw under the same degree of mouth opening as in laryngoscopy (a thick tube was kept between incisors, and the thickness was equal to the average distance of mouth opening of the patients). We observed the maximum condylar translations of the volunteers under this condition. The data were tested by 1-way analysis of variance and least significant difference testing (Table).Table.: Results and Comparisons of MeasurementsFigure.: The angle measuring method of mouth opening. A, Natural position; B, position of lower jaw actively withdrawn and mouth opened; C, mouth maximally opened. Black cross: location of condyle. Angle of mouth opening in lower jaw actively withdrawn and mouth opened: angle b minus angle a; angle of mouth opening in mouth maximally opened: angle c minus angle a.Interestingly, we observed a larger angle when the mouth was opened maximally. The condylar translation distances varied when the mouth was opened under different conditions. The condylar translation distances were slightly different when the mouths of the volunteers were in a maximally opened position and under a simulated mouth opening (27 mm) as during laryngoscopy. The condylar translation distances of the volunteers were limited when the lower jaw was protruded without opening the mouth. The present data revealed that mandibular condylar mobility, mouth opening, and angle of mouth opening can be influenced by one another. Without condylar translation, the largest angle of mouth opening cannot be obtained. Likewise, without mouth opening, the largest condylar translation distance cannot be obtained. Data from the previous study2 indicate a significant positive correlation (r = 0.41, 99% confidence interval, 0.31–0.50) between the mouth opening and the condylar translation distance, even though the correlation was not high. This finding can be used to support the aforementioned statement. This result may partly explain the concern raised by Liang et al, that is, with anterior or inferior condylar translation, the angle of mouth opening can increase. The present data also reveal that the condylar translation distance under simulated mouth opening as during laryngoscopy is similar to that under the condition of a maximally opened mouth. However, the question remains whether the mandibular condyle can achieve further translation when patients are undergoing laryngoscopy and are paralyzed. Unfortunately, we did not accurately measure the condylar translation distance under the laryngoscopy condition. The measurement results were inconclusive because probe stability during laryngoscopy was difficult to maintain. To the best of our knowledge, further condylar translation is not likely to occur when patients are undergoing laryngoscopy and paralyzed, except for the patients suffering from temporomandibular joint pain. We agree with Liang et al1 that clinicians need to understand the anatomical and physiological mechanisms underlying each predicting variable. We also thank them for providing an in-depth discussion, which was not present in the original article. Weidong Yao, MDBin Wang, MDXiaoju Jin, MDDepartment of AnesthesiologyThe First Affiliated Hospital of Wannan Medical CollegeWuhu, China Yuanhai Li, MD, PhDDepartment of AnesthesiologyThe First Affiliated Hospital of Anhui Medical UniversityHefei, China[email protected]

Characterization of polyurethane foam (PUF) and sorbent impregnated PUF (SIP) disk passive air samplers for measuring organophosphate flame retardants

This study aimed to characterize the uptake of organophosphate esters (OPEs) by polyurethane foam (PUF) and sorbent-impregnated polyurethane foam (SIP) disk passive air samplers (PAS). Atmospheric OPE concentrations were monitored with high-volume active air samplers (HV-AAS) that were co-deployed with passive air samplers. Samples were analyzed for tris(2-chloroisopropyl) phosphate (TCIPP), tri(phenyl) phosphate (TPhP), tris(2-chloroethyl) phosphate (TCEP), and tris(2,3-dichloropropyl) phosphate (TDCIPP). The mean concentration of ∑OPEs in air was 2650 pg/m3 for the HV-AAS. Sampling rates and the passive sampler medium (PSM)-air partition coefficient (KPSM−Air) were calculated for individual OPEs. The average calculated sampling rates (R) for the four OPEs were 3.6 ± 1.2 and 4.2 ± 2.0 m3/day for the PUF and SIP disks, respectively, and within the range of the recommended default value of 4 ± 2 m3/day. Since most of the OPEs remained in the linear uptake phase during the study, COSMO-RS solvation theory and an oligomer-based model were used to estimate KPUF-Air for the OPEs. The estimated values of log KPUF-Air were 7.45 (TCIPP), 9.35 (TPhP), 8.44 (TCEP), and 9.67 (TDCIPP). Finally, four configurations of the PUF and SIP disks were tested by adjusting the distance of the gap opening between the upper and lower domes of the sampler housing: i.e. 2 cm, 1 cm, no gap and 1 cm overlap. The sampling rate did not differ significantly between these four configurations (p < 0.05).

Effect of Wedge Insertion Angle on Posterior Tibial Slope in Medial Opening Wedge High Tibial Osteotomy.

Background:Medial opening wedge high tibial osteotomy (HTO) is a well-established surgery for medial compartment knee osteoarthritis (OA) wherein the lower extremity is realigned to shift the load distribution from the medial compartment of the knee to the lateral compartment. However, this surgery is known to affect the posterior tibial slope angle (PTSA), which could lead to abnormal knee kinematics and instability, and eventually to knee OA. Although PTSA control is as important as coronal realignment, few appropriate measurements for this parameter have been reported. The placement of a wedge spacer might have an effect on PTSA.Purpose:To elucidate the relationship between the PTSA and the direction of insertion of a wedge spacer.Study Design:Case series; Level of evidence, 4.Methods:This study assessed 43 knees from 34 patients who underwent medial opening wedge HTO for knee OA. Pre- and postoperative lateral radiographs of the knee as well as postoperative computed tomography scans were performed to evaluate the relationship among PTSA, wedge insertion angle (WIA), and opening gap ratio (distance of the anterior opening gap/distance of the posterior opening gap at the osteotomy site).Results:The PTSA significantly increased from 9.0° ± 2.8° preoperatively to 13.2° ± 4.1° postoperatively (P < .001), resulting in a mean ΔPTSA of 4.7° ± 4.5°. The mean opening gap ratio was 0.86 ± 0.11, and the mean WIA was 25.9° ± 8.4°. The WIA and opening gap ratio were both highly correlated with ΔPTSA (r = 0.71 and 0.72, respectively), implying that a smaller WIA or smaller gap ratio leads to less increase in posterior slope.Conclusion:The direction of wedge insertion is highly correlated with PTSA increase, which suggests that the PTSA can be controlled for by adjusting the direction of wedge insertion during surgery.Clinical Relevance:Study results suggest that it is possible to adjust the PTSA by controlling the WIA during surgery. Proper attention to WIA can avoid an iatrogenic increase in posterior tibial slope.

Swallowing Function Defined by Videofluoroscopic Swallowing Studies after Anterior Cervical Discectomy and Fusion: a Prospective Study.

This study evaluated factors related to swallowing dysfunction after anterior cervical discectomy and fusion (ACDF) using videofluoroscopic swallowing studies (VFSS). Preoperative and postoperative VFSSs were done with 5 mL diluted barium. Oral transit time, pharyngeal delay time, pharyngeal response time (PRT), and pharyngeal transit time were measured. Hyoid bone movement and upper esophageal sphincter (UES) diameter were measured serially. Thickness of prevertebral soft tissue was measured from digitized VFSS images. In results, 12 of 20 patients showed abnormal postoperative VFSS findings. PRT decreased significantly after surgery. Hyoid bone movement did not change significantly after surgery. The maximal distance of UES opening decreased significantly after surgery, and the higher the level of surgery (C3 > C4 > C5 > C6), the greater the decrease in maximal distance of the UES opening after surgery. The time to widest opening of the UES was prolonged significantly. At the C3 and C4 levels, the change in prevertebral soft tissue thickness of patients with VFSS abnormalities was significantly greater than those without abnormalities. In conclusion, patients after ADCF with their highest surgery level at C3 and C4 showed more abnormal VFSS findings, significantly increased soft tissue thickness, and decreased maximal distance of UES opening. VFSS provided objective data related with swallowing dysfunction after ACDF.