Comparison of actual surgical outcomes and 3-dimensional surgical simulations

PURPOSE: The advent of imaging software programs has proved to be useful for diagnosis, treatment planning, and outcome measurement, but precision of 3-dimensional (3D) surgical simulation still needs to be tested. This study was conducted to determine whether the virtual surgery performed on 3D models constructed from cone-beam computed tomography (CBCT) can correctly simulate the actual surgical outcome and to validate the ability of this emerging technology to recreate the orthognathic surgery hard tissue movements in 3 translational and 3 rotational planes of space. MATERIALS AND METHODS: Construction of pre- and postsurgery 3D models from CBCTs of 14 patients who had combined maxillary advancement and mandibular setback surgery and 6 patients who had 1-piece maxillary advancement surgery was performed. The postsurgery and virtually simulated surgery 3D models were registered at the cranial base to quantify differences between simulated and actual surgery models. Hotelling t tests were used to assess the differences between simulated and actual surgical outcomes. RESULTS: For all anatomic regions of interest, there was no statistically significant difference between the simulated and the actual surgical models. The right lateral ramus was the only region that showed a statistically significant, but small difference when comparing 2- and 1-jaw surgeries. CONCLUSIONS: Virtual surgical methods were reliably reproduced. Oral surgery residents could benefit from virtual surgical training. Computer simulation has the potential to increase predictability in the operating room.

Vertical bias in neglect: A question of time?

Neglect is defined as the failure to attend and to orient to the contralesional side of space. A horizontal bias towards the right visual field is a classical finding in patients who suffered from a right-hemispheric stroke. The vertical dimension of spatial attention orienting has only sparsely been investigated so far. The aim of this study was to investigate the specificity of this vertical bias by means of a search task, which taps a more pronounced top-down attentional component. Eye movements and behavioural search performance were measured in thirteen patients with left-sided neglect after right hemispheric stroke and in thirteen age-matched controls. Concerning behavioural performance, patients found significantly less targets than healthy controls in both the upper and lower left quadrant. However, when targets were located in the lower left quadrant, patients needed more visual fixations (and therefore longer search time) to find them, suggesting a time-dependent vertical bias.

Treatment of hemispatial neglect by means of rTMS--a review

Hemispatial neglect - defined as the failure to attend, explore, and act upon the contralesional side of space - is a frequent and disabling neurological syndrome. Interhemispheric rivalry is considered as a major pathophysiological mechanism underlying hemispatial neglect. According to this account, the contralesional, intact hemisphere undergoes a pathological hyperactivity due to a deficient transcallosal inhibition from the damaged hemisphere. This model offers a framework for possible therapeutic interventions with repetitive transcranial magnetic stimulation (rTMS), i.e. a reduction of the pathological hyperactivity with a rTMS protocol that has lasting inhibitory effects. In the present work, we will first review evidence for the interhemispheric rivalry account coming from animals and humans. We will then describe studies showing the possibility to perturb and to restore interhemispheric balance in healthy subjects as a proof of concept for therapeutic rTMS application. Finally, we will consider studies applying rTMS as a therapeutic approach in hemispatial neglect. We conclude that rTMS is a promising approach to reduce the interhemispheric imbalance in neglect patients and to ameliorate symptoms. Newly developed protocols such as Theta Burst Stimulation (TBS) - with short stimulation times and long offline effects - seem to be particularly convenient. However, future studies should assess stimulation effects not only in clinical testing, but also on disability, considering combination with traditional therapies as well.

Culture's Calling: Mobile Phones, Gender, and the Making of an African Migrant Village in Lisbon

In this article, I explore how immigrants from the West African nation of Guinea-Bissau living in Portugal use mobile phones in their daily lives in Lisbon. Whereas one might assume that mobile phones and other new information technologies facilitate transnational communication between Africa and Portugal, the ethnographic fieldwork that I conducted in Lisbon from 1999 to 2003 revealed a different scenario. Instead, mobile phones as imagined and used by the Guinean immigrants I met in Lisbon revealed less about transnationalism and globalization than they did about constructing community and identity in a new locale. As Guinean immigrants in Portugal reconfigured their relationship to their former colonizers and struggled to make their way in a new, multicultural Europe, they used their mobile phones to engage local networks, shape local identities, and transform Lisbon's sprawl into an African migrant village. Here, I highlight the gendered dimensions of this process and contend that Guinean men's and women's varied uses of mobile phones in Lisbon underscore contrasting experiences of migration, mobility, and belonging.

Culture's Calling: Mobile Phones, Gender, and the Making of an African Migrant Village in Lisbon

In this article, I explore how immigrants from the West African nation of Guinea-Bissau living in Portugal use mobile phones in their daily lives in Lisbon. Whereas one might assume that mobile phones and other new information technologies facilitate transnational communication between Africa and Portugal, the ethnographic fieldwork that I conducted in Lisbon from 1999 to 2003 revealed a different scenario. Instead, mobile phones as imagined and used by the Guinean immigrants I met in Lisbon revealed less about transnationalism and globalization than they did about constructing community and identity in a new locale. As Guinean immigrants in Portugal reconfigured their relationship to their former colonizers and struggled to make their way in a new, multicultural Europe, they used their mobile phones to engage local networks, shape local identities, and transform Lisbon's sprawl into an African migrant village. Here, I highlight the gendered dimensions of this process and contend that Guinean men's and women's varied uses of mobile phones in Lisbon underscore contrasting experiences of migration, mobility, and belonging.

DEVELOPMENT OF A HUMANOID ROBOT ARM FOR USE IN URBAN ENVIRONMENTS

The Bucknell Humanoid Robot Arm project was developed in order toprovide a lightweight robotic arm for the IHMC / Bucknell University bipedal robot that will provide a means of manipulation and facilitate operations in urban environments. The resulting fabricated arm described in this thesis weighs only 13 pounds, and is capable of holding 11 pounds fully outstretched, lifting objects such as tools, and it can open doors. It is also capable of being easily integrated with the IHMC / Bucknell University biped. This thesis provides an introduction to robots themselves, discusses the goals of the Bucknell Humanoid Robot Arm project, provides a background on some of the existing robots, and shows how the Bucknell Humanoid Robot Arm fits in with the studies that have been completed. After reading these studies, important items such as design trees and operational scenarios were completed. The completion of these items led to measurable specifications and later the design requirements and specifications. A significant contribution of this thesis to the robotics discipline involves the design of the actuator itself. The arm uses of individual, lightweight, compactly designed actuators to achieve desired capabilities and performance requirements. Many iterations were completed to get to the final design of each actuator. After completing the actuators, the design of the intermediate links and brackets was finalized. Completion of the design led to the development of a complex controls system which used a combination of Clanguage and Java.

An Investigation On The Use Of Microalgae For Biogas Enrichment

There is a need for biomethane capture and carbon dioxide sequestration to mitigate evident global climate change. This research work investigated the potential for microalgae to remove CO2 from biogas as a biotechnical method for upgrading the thermal value for subsequent compression, liquification, or introduction to natural gas pipelines. Because biogas is largely methane, the effect of high methane environments on mixed microalgae was explored and found that specific carbon utilization rates were not statistically different when microalgae were exposed to biogas environments (70% v/v CH4) , relative to high CO2 environment. The uses of conventional bubbled column photobioreactors (PBR) were assessed for CO2 removal and subsequent CH4 enrichment. A continuously-bubbled biogas PBR (cB-PBR5) and intermittently-bubbled biogas PBR (iB-PBR) experienced CO2 loading rates of about 1664 and 832 mg C/L*day and showed 30.0 and 60.1 % carbon removal, respectively. However, a lack of biogas enrichment and issues associated growth inhibition due to high CO2 environments as well as stripping the dissolved gases, namely oxygen and nitrogen, from the bulk liquid and introduction to the outlet gas prompted the consideration for gas/liquid separation using nonporous hollow-fiber (HF) membranes for CO2 transfer. The potential for two non-porous HF membrane materials [polydimethylsiloxane (PDMS) and composite polyurethane (PU)] were modeled along fiber length using a mechanistic model based on polymeric material transport properties (Gilmore et al., 2009). Based on a high CO2:CH4 permeability selectivity for PU of 76.2 the model predicted gas enrichment along an 8.5 cm fiber length. Because PDMS permeability selectivity is low (3.5), evident gas transfer was not predicated along a 34.3 cm length. Both of these HF materials were implemented in hollow-fiber membrane-carbonated biofilm (HFMcB) PBRs for microalgal-mediated biogas enrichment. Phototrophic biofilm colonization occurred on the membrane, where CO2 concentration was greatest. The presence of a biofilm demonstrated greater resiliency to high CO2 environments, compared to the conventional PBRs. However, as the PDMS model predicted, the PDMS HFMcBs did not demonstrate gas enrichment. These reactors received CO2 loading rates of 200 mg C/L*day based on PDMS permeability flux and showed approximately 65% removal of the total C transferred across the membrane. Thus, the HFMcBs demonstrated controlled carbonation of the bulk liquid via a nonporous HF membrane. Likewise, the experimental PU HFMcB did not show gas enrichment yet this result should be further explored due to the high permeability selectivity of the polymeric material. Chemical stratifications, namely pH and dissolved O2, present in a PDMS membrane-carbonated biofilm were analyzed using electrochemical microsensors. Results indicated that high DO (20 mg L-1) exists at surface of the biofilm where light availability is greatest and low pH microenvironments (pH=5.40) exist deep in the biofilm where the diffusive flux of CO2 drives transfer through the biofilm. The presence of a 400-600 ¿m liquid phase boundary layer was evident from microsensor profiles. Cryosectioning of the biofilm samples showed the biofilm to be approximately 1.17 ± 0.07 mm thick, suggesting that the high localized concentration of biomass associated with the phototrophic biofilm aided in overcoming inhibition in a microenvironment dominated by CO2(aq). Challenges of biofilm detachment and PBR fouling as well as microalgal growth inhibition in the presence of high CO2 content remain for applications of microalgae for biogas enrichment.

An ethnobotanical survey of the economic and cultural significance of non-timber forest products in the southwest Rhodope Mountain region of Bulgaria

The people of the southwestern Rhodope Mountains of Bulgaria live in small, mountainous villages and rural areas. They rely on berries, herbs, and mushrooms provided by the forest and maintain a lifestyle and culture of gathering them. This study determined the economic and landscape concentration of Non-Timber Forest Products (NTFPs) and how this has changed in the past twenty years in the region of Garmen. The objective was to gauge the cultural and economic significance of NTFPs in the lives of the people who live there. Data was collected using informal, open-ended interviews and through participant observation. Results indicate that ethnicity influence how resources are utilized. Roma people collect mushrooms for income generation; Orthodox Bulgarians gather herbs, berries, and mushrooms for medicinal purposes, to supplement their diets, and to carry on traditions. Bulgarian Muslims collect for a combination of the aforementioned reasons. Changes that occur in the forests affect each of the ethnic groups in different ways and forest management practices should include people’s knowledge and uses of NTFPs.

Laser Thomson scattering measurements of electron temperature and density in a Hall-effect plasma

Hall-effect thrusters (HETs) are compact electric propulsion devices with high specific impulse used for a variety of space propulsion applications. HET technology is well developed but the electron properties in the discharge are not completely understood, mainly due to the difficulty involved in performing accurate measurements in the discharge. Measurements of electron temperature and density have been performed using electrostatic probes, but presence of the probes can significantly disrupt thruster operation, and thus alter the electron temperature and density. While fast-probe studies have expanded understanding of HET discharges, a non-invasive method of measuring the electron temperature and density in the plasma is highly desirable. An alternative to electrostatic probes is a non-perturbing laser diagnostic technique that measures Thomson scattering from the plasma. Thomson scattering is the process by which photons are elastically scattered from the free electrons in a plasma. Since the electrons have thermal energy their motion causes a Doppler shift in the scattered photons that is proportional to their velocity. Like electrostatic probes, laser Thomson scattering (LTS) can be used to determine the temperature and density of free electrons in the plasma. Since Thomson scattering measures the electron velocity distribution function directly no assumptions of the plasma conditions are required, allowing accurate measurements in anisotropic and non-Maxwellian plasmas. LTS requires a complicated measurement apparatus, but has the potential to provide accurate, non-perturbing measurements of electron temperature and density in HET discharges. In order to assess the feasibility of LTS diagnostics on HETs non-invasive measurements of electron temperature and density in the near-field plume of a Hall thruster were performed using a custom built laser Thomson scattering diagnostic. Laser measurements were processed using a maximum likelihood estimation method and results were compared to conventional electrostatic double probe measurements performed at the same thruster conditions. Electron temperature was found to range from approximately 1 – 40 eV and density ranged from approximately 1.0 x 1017 m-3 to 1.3 x 1018 m-3 over discharge voltages from 250 to 450 V and mass flow rates of 40 to 80 SCCM using xenon propellant.

Syntheses and structures of molybdenum and tungsten complexes capable of epoxidaton and copper coordination polymers and dendrimers

We are interested in the syntheses of new complexes and in their characterization by single crystal X-ray diffraction techniques. Once we understand the structures, studies aimed at understanding uses of these complexes in the field of catalytic epoxidation using complexes soluble in water and syntheses of thin films (not assessed) were conducted. The syntheses, characterization and catalytic properties of a series of mononuclear, dinuclear and tetranuclear molybdenum and tungsten oxo complexes are described. The syntheses and structural characterization of two copper coordination polymers with 3,5-dihydroxylbenzoate ligand, and five paddlewheel shaped copper dendrimers coordinated with Fréchet-type dendrons are also detailed. The background of this dissertation is outlined in Chapter 1. Chapter 2 describes the syntheses, and characterization of two new mononuclear molybdenum(VI) and tungsten(VI) oxo complexes, MoO2Cl2(OPPh2CH2OH)2, and WO2Cl2(OPPh2CH2OH)2, bearing hydrophilic phosphine oxide ligand. The catalytic properties of these complexes for the epoxidation of cis-cyclooctene were also studied. Two new dinuclear molybdenum(VI) and tungsten(VI) oxo complexes Mo2O4Cl2[(HOCH2)PhPOO]2, and (CH3O)2(O)W(μ-O)(μ-O2PPh2)2W(O)(CH3O)2, bearing organophosphinate ligand are described in Chapter 3 and 4. Chapter 4 and 5 describes the syntheses and characterization of tetranuclear molybdenum(V) oxo complexes bearing various organophosphinate ligands. The catalytic abilities of these complexes for the epoxidation of cis-cyclooctene in the presence of hydrogen peroxide as oxidant were explored as well. Various spectroscopic methods, such as IR, UV-vis, and NMR are used to characterize the nature of these complexes. Crystal structures of compounds MoO2Cl2(OPPh2CH2OH)2, WO2Cl2(OPPh2CH2OH)2, Mo2O4Cl2[(HOCH2)PhPOO]2, (CH3O)2(O)W(μ-O)(μ-O2PPh2)2W(O)(CH3O)2, and Mo4(µ3-O)4(µ-O2PR2)4O4 (R=Ph, Me, ClCH2, o-C6H4(CH2)2) are also presented. The syntheses, and structural characterization of three copper(II) coordination polymers bearing 3,5-dihydroxybenzoate ligand are described in Chapter 6. Two copper(II) coordination polymers, [Cu2(3,5-dhb)2(pyridine)4]n, and [Cu2(3,5-dhb)4]n were afforded based on different amount of pyridine used in the reaction. The structures of these complexes are further built into 2D or 3D networks via inter or intra hydrogen bonds. The syntheses and structural characterization of the zinc(II) monomer, Zn(3,5-dhb)2(pyridine)2 is also described in this Chapter. Chapter 7 describes the syntheses, and characterization of five dendronized dicopper complexes bearing different generations of Fréchet-type dendrons. The structures of 3,5- bis(benzoyloxl)benzoic acid, 3,5-(PhCOO)2PhCOOH (G1), Cu2(3,5-dhb)4(THF)2, Cu2(G1)4(pyridine)2, and Cu2(G1)4(CH3OH)2 were characterized unambiguously by single X-ray diffraction. In addition, all compounds were characterized by FT-IR, UV-vis spectroscopy and elemental analyses.

Driver Safety in Far-side and Far-oblique Crashes: A Study of Patrol Vehicles in the United States of America

The dissertation titled "Driver Safety in Far-side and Far-oblique Crashes" presents a novel approach to assessing vehicle cockpit safety by integrating Human Factors and Applied Mechanics. The methodology of this approach is aimed at improving safety in compact mobile workspaces such as patrol vehicle cockpits. A statistical analysis performed using Michigan state's traffic crash data to assess various contributing factors that affect the risk of severe driver injuries showed that the risk was greater for unrestrained drivers (OR=3.38, p<0.0001) and for incidents involving front and far-side crashes without seatbelts (OR=8.0 and 23.0 respectively, p<0.005). Statistics also showed that near-side and far-side crashes pose similar threat to driver injury severity. A Human Factor survey was conducted to assess various Human-Machine/Human-Computer Interaction aspects in patrol vehicle cockpits. Results showed that tasks requiring manual operation, especially the usage of laptop, would require more attention and potentially cause more distraction. A vehicle survey conducted to evaluate ergonomics-related issues revealed that some of the equipment was in airbag deployment zones. In addition, experiments were conducted to assess the effects on driver distraction caused by changing the position of in-car accessories. A driving simulator study was conducted to mimic HMI/HCI in a patrol vehicle cockpit (20 subjects, average driving experience = 5.35 years, s.d. = 1.8). It was found that the mounting locations of manual tasks did not result in a significant change in response times. Visual displays resulted in response times less than 1.5sec. It can also be concluded that the manual task was equally distracting regardless of mounting positions (average response time was 15 secs). Average speeds and lane deviations did not show any significant results. Data from 13 full-scale sled tests conducted to simulate far-side impacts at 70 PDOF and 40 PDOF was used to analyze head injuries and HIC/AIS values. It was found that accelerations generated by the vehicle deceleration alone were high enough to cause AIS 3 - AIS 6 injuries. Pretensioners could mitigated injuries only in 40 PDOF (oblique) impacts but are useless in 70 PDOF impacts. Seat belts were ineffective in protecting the driver's head from injuries. Head would come in contact with the laptop during a far-oblique (40 PDOF) crash and far-side door for an angle-type crash (70 PDOF). Finite Element analysis head-laptop impact interaction showed that the contact velocity was the most crucial factor in causing a severe (and potentially fatal) head injury. Results indicate that no equipment may be mounted in driver trajectory envelopes. A very narrow band of space is left in patrol vehicles for installation of manual-task equipment to be both safe and ergonomic. In case of a contact, the material stiffness and damping properties play a very significant role in determining the injury outcome. Future work may be done on improving the interiors' material properties to better absorb and dissipate kinetic energy of the head. The design of seat belts and pretensioners may also be seen as an essential aspect to be further improved.

RAPID SPACE TRAJECTORY GENERATION USING A FOURIER SERIES SHAPE-BASED APPROACH

With the insatiable curiosity of human beings to explore the universe and our solar system, it is essential to benefit from larger propulsion capabilities to execute efficient transfers and carry more scientific equipment. In the field of space trajectory optimization the fundamental advances in using low-thrust propulsion and exploiting the multi-body dynamics has played pivotal role in designing efficient space mission trajectories. The former provides larger cumulative momentum change in comparison with the conventional chemical propulsion whereas the latter results in almost ballistic trajectories with negligible amount of propellant. However, the problem of space trajectory design translates into an optimal control problem which is, in general, time-consuming and very difficult to solve. Therefore, the goal of the thesis is to address the above problem by developing a methodology to simplify and facilitate the process of finding initial low-thrust trajectories in both two-body and multi-body environments. This initial solution will not only provide mission designers with a better understanding of the problem and solution but also serves as a good initial guess for high-fidelity optimal control solvers and increases their convergence rate. Almost all of the high-fidelity solvers enjoy the existence of an initial guess that already satisfies the equations of motion and some of the most important constraints. Despite the nonlinear nature of the problem, it is sought to find a robust technique for a wide range of typical low-thrust transfers with reduced computational intensity. Another important aspect of our developed methodology is the representation of low-thrust trajectories by Fourier series with which the number of design variables reduces significantly. Emphasis is given on simplifying the equations of motion to the possible extent and avoid approximating the controls. These facts contribute to speeding up the solution finding procedure. Several example applications of two and three-dimensional two-body low-thrust transfers are considered. In addition, in the multi-body dynamic, and in particular the restricted-three-body dynamic, several Earth-to-Moon low-thrust transfers are investigated.

Chinese Internet language: A sociolinguistic analysis of adaptations of the Chinese writing system

This paper examines the adaptations of the writing system in Internet language in mainland China from a sociolinguistic perspective. A comparison is also made of the adaptations in mainland China with those that Su (2003) found in Taiwan. In Computer-Mediated Communication (CMC), writing systems are often adapted to compensate for their inherent inadequacies (such as difficulty in input). Su (2003) investigates the creative uses of the writing system on the electronic bulletin boards (BBS) of two college student organizations in Taipei, Taiwan, and identifies four popular and creative uses of the Chinese writing system: stylized English, stylized Taiwanese-accented Mandarin, stylized Taiwanese, and the recycling of a transliteration alphabet used in elementary education. According to Coupland (2001; cited in Su 2003), stylization is “the knowing deployment of culturally familiar styles and identities that are marked as deviating from those predictably associated with the current speaking context”. Within this framework and drawing on the data in previous publications on Internet language and online sources, this study identifies five types of adaptations in mainland China’s Internet language: stylized Mandarin (e.g., 漂漂 piāopiāo for 漂亮 ‘beautiful’), stylized dialect-accented Mandarin (e.g., 灰常 huīcháng for 非常 ‘very much’), stylized English (e.g., 伊妹儿 yīmèier for ‘email’), stylized initials (e.g., bt 变态 biàntài for ‘abnormal’; pk, short form for ‘player kill’), and stylized numbers (e.g., 9494 jiùshi jiùshi 就是就是 ‘that is it’). The Internet community is composed of highly mobile individuals and thus forms a weak-tie social network. According to Milroy and Milroy (1992), a social network with weak ties is often where language innovation takes place. Adaptations of the Chinese writing system in Internet language provide interesting evidence for the innovations within a weak-tie social network. Our comparison of adaptations in mainland China and Taiwan shows that, in maximizing the effectiveness and functionality of their communication, participants of Internet communication are confronted with different language resources and situations, including differences in Romanization systems, English proficiency level, and attitudes towards English usage. As argued by Milroy and Milroy (1992), a weak-tie social network model can bridge the social class and social network. In the Internet community, the degree of diversity of the stylized linguistic varieties indexes the virtual and/or social status of its participants: the more diversified one’s Internet language is, the higher is his/her virtual and/or social status.

Google Books and Fair Use: A Tale of Two Copyrights?

On 14 November 2013, the US District Court of the Southern District of New York issued a major ruling in favour of the Google Books project, concluding that Google’s unauthorized scanning and indexing of millions of copyrighted books in the collections of participating libraries and subsequently making snippets of these works available online through the “Google Books” search tool qualifies as a fair use under section 107 USCA. After assuming that Google’s actions constitute a prima facie case of copyright infringement, Judge Chin examined the four factors in section 107 USCA and concluded in favour of fair use on the grounds that the project provides “significant public benefits,” that the unauthorized use of copyrighted works (a search tool of scanned full-text books) is “highly transformative” and that it does not supersede or supplant these works. The fair use defence also excluded Google’s liability for making copies of scanned books available to the libraries (as well as under secondary liability since library actions were also found to be protected by fair use): it is aimed at enhancing lawful uses of the digitized books by the libraries for the advancement of the arts and sciences. A previous ruling by the same court of 22 March 2011 had rejected a settlement agreement proposed by the parties, on the grounds that it was “not fair, adequate, and reasonable”. The Authors Guild has appealed the ruling.