•Learning two languages from birth has no effect on cortical thickness compared to learning only one language.•In the bilingual brain, the later a second language is acquired the greater the effect ...on cortical thickness.•In the left inferior frontal gyrus, cortical thickness increases with age of acquisition of second language.•In the right inferior frontal gyrus, cortical thickness decreases with age of acquisition of second language.
We examined the effects of learning a second language (L2) on brain structure. Cortical thickness was measured in the MRI datasets of 22 monolinguals and 66 bilinguals. Some bilingual subjects had learned both languages simultaneously (0–3years) while some had learned their L2 after achieving proficiency in their first language during either early (4–7years) or late childhood (8–13years). Later acquisition of L2 was associated with significantly thicker cortex in the left inferior frontal gyrus (IFG) and thinner cortex in the right IFG. These effects were seen in the group comparisons of monolinguals, simultaneous bilinguals and early and late bilinguals. Within the bilingual group, significant correlations between age of acquisition of L2 and cortical thickness were seen in the same regions: cortical thickness correlated with age of acquisition positively in the left IFG and negatively in the right IFG. Interestingly, the monolinguals and simultaneous bilinguals did not differ in cortical thickness in any region. Our results show that learning a second language after gaining proficiency in the first language modifies brain structure in an age-dependent manner whereas simultaneous acquisition of two languages has no additional effect on brain development.
PurposeThe capacity of landfills will reach saturation in the 2020s. There are more than 50,000 buildings in Hong Kong over 30 years old and which may require extensive refurbishment under the ...Mandatory Building Scheme. Additionally, most new owners/tenants tend to renovate their premises before moving in. Hence, there is an urgent need in Hong Kong, to explore strategies and measures to enable the development of effective refurbishment and renovation (R&R) waste management for such projects. The objectives of this paper are to investigate the process of R&R for identifying the perceived barriers and thereby the strategies for minimisation and management of R&R waste in Hong Kong.Design/methodology/approachDesktop study, semi-structured interviews, site observations and document reviews were used as the data collection methods to achieve the objectives of this research. Considering the nature and characteristics of the industry structure, the snowball sampling process was deployed for data collection. Thematic analysis and content analysis were used for data analysis. Waste minimisation and management strategies for R&R projects were then discussed and developed by the research team and a focus group meeting was held to validate the research findings. Six strategies were then proposed to the government.FindingsR&R projects contribute 10–20% of the construction and demolition waste. The barriers to recycling of R&R waste can be grouped into six major categories: (1) lack of sorting and storage spaces, (2) high cost, (3) insufficient government supporting policy, (4) complicated recycling processes, (5) immature recycling market and (6) insufficient public education. Also, six strategies are proposed in this study, which include (1) pre-refurbishment audit, (2) development of recycling market, (3) sea reclamation, (4) incineration, (5) government support and (6) education and research.Originality/valueThe strategies and measures proposed in this research could most adequately serve as reference for the government officials, building professionals and academic researchers. Such knowledge would make possible the development of effective strategies and measures for minimising and managing R&R waste.
Summary
Objective
Although a clear correlation has been observed between high‐frequency oscillations (HFOs) and the seizure‐onset zone in distinct lesions, the role of the underlying pathologic ...substrates in the generation of HFOs is not well established. We aimed to investigate HFO correlates of different pathologic substrates in patients with drug‐resistant epilepsy, and to examine the relation of HFOs with the anatomic location of the dysplastic lesion and surrounding tissue in patients with focal cortical dysplasia (FCD).
Methods
We studied consecutive patients with drug‐resistant epilepsy who underwent intracranial electroencephalography (iEEG) investigations with depth electrodes at the Montreal Neurological Institute and Hospital, between November 2004 and May 2013. Inclusion criteria were the following: a focal lesion documented by magnetic resonance imaging (MRI); EEG recording at a 2,000 Hz sampling rate; and seizures starting from depth electrode contacts placed in lesion and perilesional tissue.
Results
Thirty‐seven patients (13 FCD, 12 mesial temporal sclerosis, five cortical atrophy, three polymicrogyria, three nodular heterotopia, and one tuberous sclerosis) were included; 18 were women (median age 34). Ripples and fast ripples were found in all lesion types, except tuberous sclerosis, which showed no fast ripples. There was a significant difference in rates of ripples and fast ripples across different lesions (p < 0.001), with higher rates in FCD, mesial temporal sclerosis, and nodular heterotopia than in atrophy, polymicrogyria, and tuberous sclerosis. Regarding patients with FCD, HFOs rates differed significantly across the three types of tissue (lesional, perilesional, and nonlesional; p < 0.001), being higher within the borders of the MRI‐visible dysplastic lesion, followed by the surrounding area, and rare in the remote cortex.
Significance
Our findings suggest that in patients who are all intractable, the HFO rates vary with different pathologies, and reflect different types of neuronal derangements. Our results also emphasize the potential usefulness of HFOs as an additional method to better define the extent of the epileptogenic dysplastic tissue in FCD.
A detailed characterization study is presented of a Raman spectroscopy system designed to maximize the volume of resected cancer tissue in glioma surgery based on in vivo molecular tissue ...characterization. It consists of a hand-held probe system measuring spectrally resolved inelastically scattered light interacting with tissue, designed and optimized for in vivo measurements. Factors such as linearity of the signal with integration time and laser power, and their impact on signal to noise ratio, are studied leading to optimal data acquisition parameters. The impact of ambient light sources in the operating room is assessed and recommendations made for optimal operating conditions. In vivo Raman spectra of normal brain, cancer and necrotic tissue were measured in 10 patients, demonstrating that real-time inelastic scattering measurements can distinguish necrosis from vital tissue (including tumor and normal brain tissue) with an accuracy of 87%, a sensitivity of 84% and a specificity of 89%.
Purpose
This study aims to identify the challenges facing innovative startups in the construction environment, recommending possible self-help measures and society support.
...Design/methodology/approach
A comprehensive literature survey informed a questionnaire survey on built environment startups in Hong Kong, followed by a statistical analysis and supplemented by written views of respondents. Validation by experts confirms the survey results.
Findings
Triangulated findings highlight the problems of conservative policies, investors’ preference on short payback periods, price competition, high operation cost and a lack of promotion channels. The firm’s size and its age differentiate its networking and fund-raising capabilities.
Research limitations/implications
While the survey samples cover the spread of startups in Hong Kong’s construction/real estate industries well, the number is still limited because the city is relatively compact. The barriers and solutions may be particularly relevant to the built environment there, but also worth noting elsewhere.
Practical implications
Built environment startups are emerging and their path of development is obscured by industry barriers. While the findings reflect the current situation in Hong Kong, which is a metropolitan city with a vibrant construction market, government policies may present a varying factor in different economies. Conservatism in the construction industry may also be a hindrance, but gradual signs of improvements are seen.
Originality/value
The recommendations provided may help mitigate the problems of startup growth. They also provide insights into the construction “startup eco-system” worth the attention of policy makers and project managers, who may make better use of the innovative technology and services of built environment startups if the difficulties are alleviated.
•Refurbishment and renovation projects contribute 10 to 20% of the construction and demolition waste•Pre-refurbishment Audit is an effective strategy to be implemented in R&R waste management•The ...procedures of PRA, which involve 4 stages are described•Barriers to implementation of Pre-refurbishment Audit are provided•Government is recommended to take lead in conducting PRA and issue guidelines as a reference.
The construction industry is the major source of Construction and Demolition (C&D) waste in Hong Kong. The capacity of landfills will reach saturation in a couple of years. Refurbishment and renovation projects contribute 10 to 20% of C&D waste. There are about 50,000 buildings in Hong Kong that are more than 30 years old and may require extensive refurbishment or renovation under the Mandatory Building Inspection Scheme. Besides, most new owners/tenants will renovate their premises before moving in. There is an urgent need to explore and develop effective waste management strategies and measures for refurbishment/renovation projects in Hong Kong. This research study aims to identify the types and estimate the quantities of refurbishment and renovation (R&R) waste; and evaluate the effectiveness of Pre-refurbishment Auditing (PRA) as a waste management strategy for these projects. Desktop study, semi-structured interviews, site observations and document reviews were used as the data collection methods to achieve the objectives of this research study. Content Analysis and Thematic Analysis were used for data analysis. The findings revealed that PRA is an effective strategy to be implemented in R&R waste management. Barriers for implementing PRA include (a) lack of sorting and storage spaces; (b) high cost; (c) insufficient government supporting policy; (d) complicated recycling processes, (e) immature recycling market, and (f) insufficient public education. To tackle these obstacles, government is recommended to take lead in conducting PRA and issue guidelines as a reference. The Building Department can also consider taking up an active role in policy making and promoting PRA.
The aim of this study was to evaluate, using diffusion tensor tractography, the white matter fibers crossing the hippocampus and the amygdala, and to perform a volumetric analysis and an anatomical ...study of the connections of these 2 structures. As a second step, the authors studied the white matter tracts crossing a virtual volume of resection corresponding to a selective amygdalohippocampectomy.
Twenty healthy right-handed individuals underwent 3-T MR imaging. Volumetric regions of interest were manually created to delineate the amygdala, the hippocampus, and the volume of resection. White matter fiber tracts were parcellated using the fiber assignment for continuous tracking tractography algorithm. All fibers were registered with the anatomical volumes.
In all participants, the authors identified fibers following the hippocampus toward the fornix, the splenium of the corpus callosum, and the dorsal hippocampal commissure. With respect to the fibers crossing the amygdala, the authors identified the stria terminalis and the uncinate fasciculus. The virtual resection disrupted part of the fornix, fibers connecting the 2 hippocampi, and fibers joining the orbitofrontal cortex. The approach created a theoretical frontotemporal disconnection and also interrupted fibers joining the temporal pole and the occipital area.
This diffusion tensor tractography study allowed for good visualization of some of the connections of the amygdala and hippocampus. The authors observed that the virtual selective amygdalohippocampectomy disconnected a large number of fibers connecting frontal, temporal, and occipital areas.
Abstract Background Use of computer-assisted insertion of pedicle screws has some advantages owing to the reportedly decreased incidence of pedicle breach and clinical events. Registration-based ...methods based on preoperative computed tomography imaging, 2D fluoroscopy, and 3D fluoroscopy are the most popular, however each has its limitations. O-arm–based navigation, which uses intraoperative acquisition and registration of navigated images, may overcome many of these disadvantages. We set out to study the clinical accuracy and navigational accuracy for pedicle screw insertion using our recently acquired O-arm and present our preliminary findings. Methods The first 26 patients operated consecutively for L4-5 fusion were included in the study. O-arm–based navigation was used to insert the pedicle screws. Postoperative computed tomography images were acquired and assessed for pedicle breach and anterior cortical perforation. Planned trajectories of each screw were compared with the actual trajectories in the postoperative images to assess navigational accuracy in both axial and sagittal planes. Results A total of 104 screws were inserted. One screw (1%) breached the pedicle laterally. Nonsignificant anterolateral cortical perforations were noted in 7 screws (6.7%), all of which occurred at L5 level. The mean axial and sagittal navigational error was 2.3° (± 1.7) and 3.1° (± 2.3), respectively. There were no significant differences in the errors between L4 or L5 level. The occurrence of anterior perforation correlated with the degree of axial ( P = .02) but not sagittal ( P = .12) navigational error. There were no clinical events related to the screw insertion. Conclusion Use of O-arm–guided pedicle screw insertion was associated with low incidence of pedicle breach (1%) and a low range of navigational error in both sagittal and axial planes. Anterolateral vertebral body perforation was higher at L5 without any negative clinical events. Despite the high need for technical support, we found that O-arm was a very efficient tool for accurate pedicle screw insertion.
Cancers are often impossible to visually distinguish from normal tissue. This is critical for brain cancer where residual invasive cancer cells frequently remain after surgery, leading to disease ...recurrence and a negative impact on overall survival. No preoperative or intraoperative technology exists to identify all cancer cells that have invaded normal brain. To address this problem, we developed a handheld contact Raman spectroscopy probe technique for live, local detection of cancer cells in the human brain. Using this probe intraoperatively, we were able to accurately differentiate normal brain from dense cancer and normal brain invaded by cancer cells, with a sensitivity of 93% and a specificity of 91%. This Raman-based probe enabled detection of the previously undetectable diffusely invasive brain cancer cells at cellular resolution in patients with grade 2 to 4 gliomas. This intraoperative technology may therefore be able to classify cell populations in real time, making it an ideal guide for surgical resection and decision-making.
Background
External ventricular drain (EVD) placement is a frequently performed neurosurgical procedure. Inaccuracies in drain positioning and the need for multiple passes using the classic freehand ...insertion technique is well reported in the literature, especially in the traumatic brain injury (TBI) population. The purpose of this study was to evaluate if electromagnetic neuronavigation guidance for EVD insertion improves placement accuracy and minimizes the number of passes in severe TBI patients.
Methods
Navigation was applied prospectively for all new severe TBI patients who required ventricular catheter placement over a period of 1 year, and compared with a retrospective cohort of severe TBI patients who had EVD inserted freehand in the preceding year. The placement accuracy was evaluated using the Kakarla grading system; the number of passes was also compared.
Results
Fifty-four cases were recruited: 35 (64.8%) had their EVD placed using the freehand technique and 19 (35.2%) using navigation guidance. In the navigation group, the placement accuracy was: 94.7% (18/19) grade 1, 5.3% (1/19) grade 2, and none at grade 3. In comparison, freehand placement was associated with misplacement (grades 2 and 3) in 42.9% of the cases (
p
value = 0.009). The number of passes was significantly lower in the navigation group (mean of 1.16 ± 0.38), compared with the freehand group (mean of 1.63 ± 0.88) (
p
value = 0.018).
Conclusions
Using the navigation to guide EVD placement was associated with a significantly better accuracy and a lower number of passes in severe TBI patients.
PDF
