Postoperative Assessment of Pedicle Screws and Management of Breaches: A Survey among Canadian Spine Surgeons and a New Scoring System

Ahmed Aoude,Saber Ghadakzadeh,Hamzah Alhamzah,Maryse Fortin,Peter Jarzem,Jean A. Ouellet,Michael H. Weber 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.1

Study Design: This study was designed as a survey amongst Canadian spine surgeon to determine a scoring system to standardize pedicle screw placement assessment. Purpose: This study aimed to obtain and analyze the opinions of spine surgeons regarding the assessment of pedicle screw accuracy, with the goal of establishing clinical guidelines for interventions for malpositioned pedicle screws. Overview of Literature: Accurate placement of pedicle screws is challenging, and misalignment can lead to various complications. To date, there is no recognized gold standard for assessing pedicle screw placement accuracy. The literature is lacking studies attempting to standardize pedicle screw placement accuracy assessment. Methods: A survey of the clinical methods and imaging criteria that are used for assessing pedicle screw placement accuracy was designed and sent to orthopedic and neurosurgery spine surgeons from the Canadian Spine Society for their anonymous participation. Results: Thirty-five surgeons completed the questionnaire. The most commonly used modalities for assessing pedicle screw position postoperatively were plain X-rays (97%) and computed tomography (CT, 97%). In both symptomatic and asymptomatic patients, the most and least worrisome breaches were medial and anterior breaches, respectively. The majority of surgeons tended not to re-operate on asymptomatic breaches. More than 60% of surgeons would re-operate on patients with new-onset pain and a ≤4-mm medial or inferior breach in both thoracic and lumbar regions. If a patient experienced sensory loss and a breach on CT, in either the thoracic or lumbar levels, 90% and 70% of the surgeons would re-operate for a medial breach and an inferior breach, respectively. Conclusions: Postoperative clinical presentation and imaging findings are crucial for interpreting aberrant pedicle screw placement. This study presents a preliminary scoring system for standardizing the classification of pedicle screws.

The Effect of Ethnicity on Wideband Absorbance of Neonates with Healthy Middle Ear Functions in Malaysia: A Preliminary Study

Hamzah A Wali,Rafidah Mazlan 대한청각학회 2018 Journal of Audiology & Otology Vol.22 No.1

Background and Objectives: Although ethnicity effect on wideband absorbance (WBA) findingswas evident for adults, its effect on neonates has not been established yet. This studyaimed to investigate the influence of ethnicity on WBA measured at 0 daPa from neonateswith healthy middle ear functions. Subjects and Methods: Participants were 99 normal,healthy, full-term newborn babies with chronological age between 11 and 128 hours of age(mean=46.73, standard deviation=26.36). A cross-sectional study design was used to measureWBA at 16 one-third octave frequency points from 99 neonates comprising of threeethnic groups: Malays (n=58), Chinese (n=13) and Indians (n=28). A total of 165 ears (83.3%)that passed a battery of tests involving distortion product otoacoustic emissions, 1 kHztympanometry and acoustic stapedial reflex were further tested using WBA. Moreover, bodysize measurements were recorded from each participant. Results: The Malays and Indiansneonates showed almost identical WBA response across the frequency range while the Chinesebabies showed lower absorbance values between 1.25 kHz and 5 kHz. However, thedifferences observed in WBA between the three ethnic groups were not statistically significant(p=0.23). Additionally, there were no statistically significant difference in birth weight,height and head circumference among the three ethnic groups. Conclusions: This studyshowed that Malays, Chinese and Indians neonates were not significantly different in their WBAresponses. In conclusion, to apply for the ethnic-specific norms is not warranted when testingneonates from population constitute of these three ethnicities.

China and the freedom of navigation in the South China Sea

B A Hamzah 한국국방연구원 2010 The Korean Journal of Defense Analysis Vol.22 No.2

The parties vying for territories in the South China Sea need not fear China. Despite expanding its military presence in the South China Sea, China does not pose any palpable military threat to the region. On the contrary, a rich and strong China could be a stabilizing factor. Likewise, while there is no evidence to suggest that China, a country that depends on international trade to sustain its strategic interests globally, will interfere with the freedom of navigation as defined under customary international law in the South China Sea. However, as a proud nation with a long-established civilization it will not shy away from challenging what it considers to be unauthorized military activities in its maritime space that is within its national jurisdiction, the South China Sea included. ""The rise of a strong, prosperous China can be a source of strength for the community of nations."" .President Obama, the Suntory Hall, Tokyo, Japan, November 14, 2009.

Low-dimensional modelling of n-type doped silicene and its carrier transport properties for nanoelectronic applications

Chuan, M.W.,Lau, J.Y.,Wong, K.L.,Hamzah, A.,Alias, N.E.,Lim, C.S.,Tan, M.L.P Techno-Press 2021 Advances in nano research Vol.10 No.5

Silicene, a 2D allotrope of silicon, is predicted to be a potential material for future transistor that might be compatible with present silicon fabrication technology. Similar to graphene, silicene exhibits the honeycomb lattice structure. Consequently, silicene is a semimetallic material, preventing its application as a field-effect transistor. Therefore, this work proposes the uniform doping bandgap engineering technique to obtain the n-type silicene nanosheet. By applying nearest neighbour tight-binding approach and parabolic band assumption, the analytical modelling equations for band structure, density of states, electrons and holes concentrations, intrinsic electrons velocity, and ideal ballistic current transport characteristics are computed. All simulations are done by using MATLAB. The results show that a bandgap of 0.66 eV has been induced in uniformly doped silicene with phosphorus (PSi₃NW) in the zigzag direction. Moreover, the relationships between intrinsic velocity to different temperatures and carrier concentration are further studied in this paper. The results show that the ballistic carrier velocity of PSi₃NW is independent on temperature within the degenerate regime. In addition, an ideal room temperature subthreshold swing of 60 mV/dec is extracted from ballistic current-voltage transfer characteristics. In conclusion, the PSi₃NW is a potential nanomaterial for future electronics applications, particularly in the digital switching applications.

Nonstandard Backstepping Based Integral Sliding Mode Control of Hydraulically Actuated Active Suspension System

Flayyih Mujtaba A. Flayyih,Hamzah Mohsin N. Hamzah,Hassan Jafar M. Hassan 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.6

In this paper, the integral sliding mode control (ISMC) with non-standard backstepping is utilized for designing an automotive active suspension system hydraulic actuator. The main objective of this design is to make the suspension system’s ride more comfortable while keeping the road holding and rattling space within safe bounded limits. The controller design consists of applying the ISMC to perform a virtual control force, that meets all suspension requirements, besides utilizing a hydraulic model by a non-standard backstepping control algorithm taking into consideration the uncertainty and nonlinearity of the hydraulic system. The main advantage of ISMC is to have a robust controller, such that the stability of the system appears from starting its states at the switching surface where system nonlinearity, parameter changes, and road disturbances are rejected by a discontinuous control term present strongly in the suspension dynamics. This work demonstrates the effectiveness of the present controller design through the simulation of a 2-DOF quarter car system equipped with a passive suspension. The results vividly showcase how the current design enhances the overall performance of the system.

Part 3. Regional Maritime Disputes And Ocean Diplomacy : 6. The Prospects for Solving Territorial Problems in the Spratlys: The Need to Manage Contentious Issues

( B. A. Hamzah ) 연세대학교 동서문제연구원 1995 East and West Studies Series Vol.37 No.-

Part 5. Strengthening Regional Maritime Cooperation For The New Century : Confidence-Building Measures in the Spratlys: The need to Manage China

( B. A. Hamzah ) 연세대학교 동서문제연구원 2000 East and West Studies Series Vol.46 No.-

Two-dimensional modelling of uniformly doped silicene with aluminium and its electronic properties

Chuan, M.W.,Wong, K.L.,Hamzah, A.,Rusli, S.,Alias, N.E.,Lim, C.S.,Tan, M.L.P. Techno-Press 2020 Advances in nano research Vol.9 No.2

Silicene is a two-dimensional (2D) derivative of silicon (Si) arranged in honeycomb lattice. It is predicted to be compatible with the present fabrication technology. However, its gapless properties (neglecting the spin-orbiting effect) hinders its application as digital switching devices. Thus, a suitable band gap engineering technique is required. In the present work, the band structure and density of states of uniformly doped silicene are obtained using the nearest neighbour tight-binding (NNTB) model. The results show that uniform substitutional doping using aluminium (Al) has successfully induced band gap in silicene. The band structures of the presented model are in good agreement with published results in terms of the valence band and conduction band. The band gap values extracted from the presented models are 0.39 eV and 0.78 eV for uniformly doped silicene with Al at the doping concentration of 12.5% and 25% respectively. The results show that the engineered band gap values are within the range for electronic switching applications. The conclusions of this study envisage that the uniformly doped silicene with Al can be further explored and applied in the future nanoelectronic devices.

Effect of cathodic arc PVD parameters on roughness of TiN coating on steel substrate

M. Ali,E. Hamzah,I.A. Qazi,M.R.M. Toff 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Titanium nitride which is widely used as a hard coating material was coated on tool steel, by physical vapor deposition method. Surface roughness was investigated as a function of deposition rate, substrate bias and temperature, nitrogen flow rate and metal ion etching. The study showed that increase in surface roughness mainly depends on the condition of sample preparation, surface treatment, macro-droplets,pitting defects, rise in compressive stress at higher coating thickness, growth defects and to a lesser extent selection of surface under testing. It was observed that chromium ion etching significantly reduced the surface roughness compared to titanium ion etching.

Electronic properties of monolayer silicon carbide nanoribbons using tight-binding approach

Chuan, M.W.,Wong, Y.B.,Hamzah, A.,Alias, N.E.,Sultan, S. Mohamed,Lim, C.S.,Tan, M.L.P. Techno-Press 2022 Advances in nano research Vol.12 No.2

Silicon carbide (SiC) is a binary carbon-silicon compound. In its two-dimensional form, monolayer SiC is composed of a monolayer carbon and silicon atoms constructed as a honeycomb lattice. SiC has recently been receiving increasing attention from researchers owing to its intriguing electronic properties. In this present work, SiC nanoribbons (SiCNRs) are modelled and simulated to obtain accurate electronic properties, which can further guide fabrication processes, through bandgap engineering. The primary objective of this work is to obtain the electronic properties of monolayer SiCNRs by applying numerical computation methods using nearest-neighbour tight-binding models. Hamiltonian operator discretization and approximation of plane wave are assumed for the models and simulation by applying the basis function. The computed electronic properties include the band structures and density of states of monolayer SiCNRs of varying width. Furthermore, the properties are compared with those of graphene nanoribbons. The bandgap of ASiCNR as a function of width are also benchmarked with published DFT-GW and DFT-GGA data. Our nearest neighbour tight-binding (NNTB) model predicted data closer to the calculations based on the standard DFT-GGA and underestimated the bandgap values projected from DFT-GW, which takes in account the exchange-correlation energy of many-body effects.