“Real” three-dimensional constructive interference in steady-state imaging to discern microneurosurgical anatomy

2003 ◽  
Vol 98 (3) ◽  
pp. 625-630 ◽  
Author(s):  
Yukinari Kakizawa ◽  
Kazuhiro Hongo ◽  
Hisayoshi Takasawa ◽  
Yosuke Miyairi ◽  
Atsushi Sato ◽  
...  
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Neurosurgical Procedures ◽  
Constructive Interference ◽  
Operative Field ◽  
Content Type ◽  
Minimal Invasiveness ◽  
Endoscopic View ◽  
Computer Workstation ◽  
The Relationship

✓ Three-dimensional (3D) neuroimages are generally considered useful for neurosurgical practice. Nevertheless, neuroimaging modalities such as 3D digital subtraction angiography and 3D computerized tomography angiography are still insufficient because the resulting images fail to delineate neural structures. Complex neurosurgical procedures are mostly performed in the cerebrospinal fluid (CSF) space of the basal cistern, where vessels and neural structures are present along with the lesion. The magnetic resonance (MR) imaging—derived 3D constructive interference in steady-state (CISS) imaging displays the margin between the CSF and neural structures, vessels, and dura mater in detail, in a two-dimensional fashion. The authors know that volume-rendered 3D CISS images would be more useful for surgery than conventional ones. Although the usefulness of “virtual MR image endoscopy” was reported previously, the endoscopic view is different from the operative field because of the perspective being emphasized. Therefore, to simulate surgical views, the authors made 3D neuroimages from a 3D CISS MR sequence by using an advanced computer workstation. After generating volume images, a cutting method was used in the desired plane to visualize the lesion with reference to a multiplanar reformatted image. The authors call these “real” 3D CISS images, and they are more comparable to the operative field. This newly developed method of producing a real 3D CISS image was used in 30 cases and contributed to the understanding of the relationship between a lesion and surrounding structures before attempting neurosurgical procedures, with minimal invasiveness to the patient.

Effect of system compliance on weld power in ultrasonic additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gowtham Venkatraman ◽  
Adam Hehr ◽  
Leon M. Headings ◽  
Marcelo J. Dapino
Keyword(s):  
Additive Manufacturing ◽  
Electrical Power ◽  
Three Dimensional ◽  
Power Input ◽  
Material Strength ◽  
Content Type ◽  
Ultrasonic Additive Manufacturing ◽  
Linear Elastic ◽  
Mechanical Compliance ◽  
The Relationship

Purpose Ultrasonic additive manufacturing (UAM) is a solid-state joining technology used for three-dimensional printing of metal foilstock. The electrical power input to the ultrasonic welder is a key driver of part quality in UAM, but under the same process parameters, it can vary widely for different build geometries and material combinations because of mechanical compliance in the system. This study aims to model the relationship between UAM weld power and system compliance considering the workpiece (geometry and materials) and the fixture on which the build is fabricated. Design/methodology/approach Linear elastic finite element modeling and experimental modal analysis are used to characterize the system’s mechanical compliance, and linear system dynamics theory is used to understand the relationship between weld power and compliance. In-situ measurements of the weld power are presented for various build stiffnesses to compare model predictions with experiments. Findings Weld power in UAM is found to be largely determined by the mechanical compliance of the build and insensitive to foil material strength. Originality/value This is the first research paper to develop a predictive model relating UAM weld power and the mechanical compliance of the build over a range of foil combinations. This model is used to develop a tool to determine the process settings required to achieve a consistent weld power in builds with different stiffnesses.

scholarly journals Evaluating the Relationship between Vancomycin Trough Concentration and 24-Hour Area under the Concentration-Time Curve in Neonates

2018 ◽  
Vol 62 (4) ◽  
pp. e01647-17 ◽  
Author(s):  
Sheng-Hsuan Tseng ◽  
Chuan Poh Lim ◽  
Qi Chen ◽  
Cheng Cai Tang ◽  
Sing Teang Kong ◽  
...  
Keyword(s):  
Steady State ◽  
Trough Concentration ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Time Curve ◽  
Content Type ◽  
Concentration Time ◽  
Vancomycin Trough ◽  
Trough Concentrations ◽  
The Relationship

ABSTRACT Bacterial sepsis is a major cause of morbidity and mortality in neonates, especially those involving methicillin-resistant Staphylococcus aureus (MRSA). Guidelines by the Infectious Diseases Society of America recommend the vancomycin 24-h area under the concentration-time curve to MIC ratio (AUC24/MIC) of >400 as the best predictor of successful treatment against MRSA infections when the MIC is ≤1 mg/liter. The relationship between steady-state vancomycin trough concentrations and AUC24 values (mg·h/liter) has not been studied in an Asian neonatal population. We conducted a retrospective chart review in Singapore hospitals and collected patient characteristics and therapeutic drug monitoring data from neonates on vancomycin therapy over a 5-year period. A one-compartment population pharmacokinetic model was built from the collected data, internally validated, and then used to assess the relationship between steady-state trough concentrations and AUC24. A Monte Carlo simulation sensitivity analysis was also conducted. A total of 76 neonates with 429 vancomycin concentrations were included for analysis. Median (interquartile range) was 30 weeks (28 to 36 weeks) for postmenstrual age (PMA) and 1,043 g (811 to 1,919 g) for weight at the initiation of treatment. Vancomycin clearance was predicted by weight, PMA, and serum creatinine. For MRSA isolates with a vancomycin MIC of ≤1, our major finding was that the minimum steady-state trough concentration range predictive of achieving an AUC24/MIC of >400 was 8 to 8.9 mg/liter. Steady-state troughs within 15 to 20 mg/liter are unlikely to be necessary to achieve an AUC24/MIC of >400, whereas troughs within 10 to 14.9 mg/liter may be more appropriate.

Quantification of increased exposure resulting from orbital rim and orbitozygomatic osteotomy via the frontotemporal transsylvian approach

1999 ◽  
Vol 91 (6) ◽  
pp. 1020-1026 ◽  
Author(s):  
Marc S. Schwartz ◽  
Gregory J. Anderson ◽  
Michael A. Horgan ◽  
Jordi X. Kellogg ◽  
Sean O. McMenomey ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Zygomatic Arch ◽  
Neurosurgical Procedures ◽  
Content Type ◽  
Transsylvian Approach ◽  
Surgical Access ◽  
Stereotactic Device ◽  
Orbital Rim ◽  
Fine Print

Object. Use of orbital rim and orbitozygomatic osteotomy has been extensively reported to increase exposure in neurosurgical procedures. However, there have been few attempts to quantify the extent of additional exposure gained by these maneuvers. Using a novel laboratory technique, the authors have attempted to measure the increase in the “area of exposure” that is gained by removal of the orbital rim and zygomatic arch via the frontotemporal transsylvian approach.Methods. The authors dissected five cadavers bilaterally. The area of exposure provided by the frontotemporal transsylvian approach was determined by using a frameless stereotactic device. With the tip of a microdissector placed on targets deep within the exposure, the position of the end of the microdissector handle was measured in three-dimensional space as the microdissector was rotated around the periphery of the operative field. This maneuver was performed via the frontotemporal approach alone as well as with orbital rim and orbitozygomatic osteotomy approaches. After data manipulation, the areas of exposure corresponding to the polygons used to define these handle positions were calculated and directly compared. On average, the area of exposure provided by the frontotemporal transsylvian approach was increased 26 to 39% (p < 0.05) by adding orbital rim osteotomy and an additional 13 to 22% (not significant) with removal of the zygomatic arch.Conclusions. Significant and consistent increases in surgical exposure were obtained by using orbital osteotomy, whereas zygomatic arch removal produced less consistent gains. Both maneuvers may be expected to improve surgical access. However, because larger and more consistent gains were afforded by orbital rim removal, the threshold for removal of this portion of the orbitozygomatic complex should be lower.

scholarly journals Older workers: stereotypes and occupational self-efficacy

2016 ◽  
Vol 31 (7) ◽  
pp. 1152-1166 ◽  
Author(s):  
Rita Chiesa ◽  
Stefano Toderi ◽  
Paola Dordoni ◽  
Kene Henkens ◽  
Elena Maria Fiabane ◽  
...  
Keyword(s):  
Older Workers ◽  
Self Efficacy ◽  
Age Groups ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Age Stereotypes ◽  
Content Type ◽  
Moderator Role ◽  
The Relationship ◽  
Organizational Age

Purpose The purpose of this paper is to explore the relationship between organizational age stereotypes and occupational self-efficacy. First, the authors intend to test the measurement invariance of Henkens’s (2005) age stereotypes scale across two age group, respectively, under 50 and 50 years and older. Then, the moderator role of age groups in the relationship between age stereotypes and occupational self-efficacy is investigated. Design/methodology/approach The survey involved a large sample of 4,667 Italian bank sector’s employees. Findings The results show the invariance of the three dimensional structure of organizational stereotypes towards older workers scale: productivity, reliability and adaptability. Furthermore, the moderation is confirmed: the relationship between organizational age stereotypes and occupational self-efficacy is significant only for older respondents. Research limitations/implications Future studies should aim to replicate the findings with longitudinal designs. Practical implications The study suggests the importance to emphasize the positive characteristics of older workers and to reduce the presence of negative age stereotypes in the workplace, especially in order to foster the occupational self-efficacy of older workers. Originality/value The findings are especially relevant in view of the lack of evidence about the relationship between age stereotypes and occupational self-efficacy.

scholarly journals Evaluation of syringomyelia with three-dimensional constructive interference in a steady state (CISS) sequence

2000 ◽  
Vol 11 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Toshinori Hirai ◽  
Yukunori Korogi ◽  
Yoshinori Shigematsu ◽  
Takeshi Sugahara ◽  
Mutsumasa Takahashi ◽  
...  
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Constructive Interference ◽  
Ciss Sequence

A framework for the relationship implications of additive manufacturing (3D printing) for industrial marketing: servitization, sustainability and customer empowerment

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Damien Chaney ◽  
Julien Gardan ◽  
Julien De Freyman
Keyword(s):  
Additive Manufacturing ◽  
Industrial Revolution ◽  
Three Dimensional ◽  
Customer Relationships ◽  
Layer By Layer ◽  
Content Type ◽  
Industrial Marketing ◽  
Sustainable Value ◽  
Value Propositions ◽  
The Relationship

Purpose The purpose of this paper is to present the relationship implications of additive manufacturing (AM), which has the ability to produce layer-by-layer three-dimensional complex products by adding material in comparison to traditional manufacturing processes which remove material – for industrial marketing. Design/methodology/approach After presenting the literature on customer relationships and digital technologies in business-to-business, the study uses a “zoom-out” and “zoom-in” perspective to review the extant literature on AM and then makes study propositions for industrial marketing. Findings Through the adoption of AM technologies, the study suggests that firms can improve their level of servitization through customized products, offer more sustainable value propositions and empower their customers through the sale of digital files, which can be considered as levers to strengthen relationships with customers. Research limitations/implications This paper makes several propositions regarding the relationship implications of AM for industrial marketing that further research should test. Practical implications This paper highlights the relational benefits that adopting AM may represent for companies. Originality/value While AM which is considered as an industrial revolution has generated a wide body of research in engineering and operations and technology management sciences, its impact on industrial marketing remains understudied.

Three dimensional simulations and stability analysis for convection induced by absorption of radiation

2015 ◽  
Vol 25 (4) ◽  
pp. 810-824 ◽  
Author(s):  
Akil Jassim Harfash
Keyword(s):  
Steady State ◽  
Stability Analysis ◽  
Fluid Layer ◽  
Three Dimensional ◽  
Linear Instability ◽  
Selective Absorption ◽  
Content Type ◽  
Linear Threshold ◽  
Divergence Equation ◽  
Three Dimensional Simulations

Purpose – The purpose of this paper is to investigate a model for convection induced by the selective absorption of radiation in a fluid layer. The concentration based internal heat source is modelled quadratically. Both linear instability and global nonlinear energy stability analyses are tested using three dimensional simulations. The results show that the linear threshold accurately predicts on the onset of instability in the basic steady state. However, the required time to arrive at the steady state increases significantly as the Rayleigh number tends to the linear threshold. Design/methodology/approach – The author introduce the stability analysis of the problem of convection induced by absorption of radiation in fluid layer, then the author select a situations which have very big subcritical region. Then, the author develop a three dimensions simulation for the problem. To do this, first, the author transform the problem to velocity – vorticity formulation, then the author use a second order finite difference schemes. The author use implicit and explicit schemes to enforce the free divergence equation. The size of the Box is evaluated according to the normal modes representation. Moreover, the author adopt the periodic boundary conditions for velocity and temperature in the $x, y$ dimensions. Findings – This paper explores a model for convection induced by the selective absorption of radiation in a fluid layer. The results demonstrate that the linear instability thresholds accurately predict the onset of instability. A three-dimensional numerical approach is adopted. Originality/value – As the author believe, this paper is one of the first studies which deal with study of stability of convection using a three dimensional simulation. When the difference between the linear and nonlinear thresholds is very large, the comparison between these thresholds is very interesting and useful.

Stakeholder power and corporate social performance

2014 ◽  
Vol 14 (3) ◽  
pp. 363-381 ◽  
Author(s):  
Béchir Ben Lahouel ◽  
Jean-Marie Peretti ◽  
David Autissier
Keyword(s):  
Stakeholder Theory ◽  
Corporate Social Performance ◽  
Social Performance ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Content Type ◽  
Strategic Posture ◽  
Corporate Social ◽  
The Relationship

Purpose – This paper aims to explore the power of one of the primary organizational stakeholders (shareholders) in the development of a corporate social performance (CSP) score. Few research works in the CSP empirical literature have studied the relationship between stakeholder power and CSP. Design/methodology/approach – Stakeholder theory is used as a theoretical framework to explain how shareholder voting power can influence the CSP level of French publicly listed companies. Stakeholder theory is tested through the operationalization of Ullmann’s (1985) three-dimensional model. Hypotheses related to shareholder voting power, strategic posture and financial performance are formulated through a literature review. A Data Envelopment Analysis approach was presented as a strong tool to measure CSP level. Multiple linear regressions were undertaken to test the hypotheses in a sample of 129 French companies between 2006 and 2007. Findings – The results indicate that companies with dispersed ownership and high proportion of institutional shareholders record a high score of CSP. Strategic posture measured by the implementation of environmental certification standard was positively and significantly related to CSP. Financial performance does not affect significantly the level of CSP. Originality/value – This paper is the first to empirically analyse the relationship between Ullmann’s three-dimensional model and CSP level in the French context. It offers to managers a better understanding of the power that certain stakeholders can use to acquire satisfaction.

Imaging of the normal pontine cisternal segment of the abducens nerve, using three-dimensional constructive interference in the steady state MRI

1999 ◽  
Vol 41 (5) ◽  
pp. 384-386 ◽  
Author(s):  
M. Lemmerling ◽  
G. De Praeter ◽  
K. Mortelé ◽  
S. Vyt ◽  
B. Vanzieleghem ◽  
...  
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Abducens Nerve ◽  
Constructive Interference
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