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The relationship between the subtypes of psychotic experiences (PEs) and common mental health symptoms remains unclear. The current study aims to establish the 12-month prevalence of PEs in a representative sample of community-dwelling Chinese population in Hong Kong and explore the relationship of types of PEs and common mental health symptoms.
This is a population-based two-phase household survey of Chinese population in Hong Kong aged 16–75 (N = 5719) conducted between 2010 and 2013 and a 2-year follow-up study of PEs positive subjects (N = 152). PEs were measured with Psychosis Screening Questionnaire (PSQ) and subjects who endorsed any item on the PSQ without a clinical diagnosis of psychotic disorder were considered as PE-positive. Types of PEs were characterized using a number of PEs (single v. multiple) and latent class analysis. All PE-positive subjects were assessed with common mental health symptoms and suicidal ideations at baseline and 2-year follow-up. PE status was also assessed at 2-year follow-up.
The 12-month prevalence of PEs in Hong Kong was 2.7% with 21.1% had multiple PEs. Three latent classes of PEs were identified: hallucination, paranoia and mixed. Multiple PEs and hallucination latent class of PEs were associated with higher levels of common mental health symptoms. PE persistent rate at 2-year follow-up was 15.1%. Multiple PEs was associated with poorer mental health at 2-year follow-up.
Results highlighted the transient and heterogeneous nature of PEs, and that multiple PEs and hallucination subtype of PEs may be specific indices of poorer common mental health.
It is well-known that attention deficit hyperactivity disorder (ADHD) is associated with changes in the dopaminergic system. However, the relationship between central dopaminergic tone and the blood oxygen level-dependent (BOLD) signal during receipt of rewards and penalties in the corticostriatal pathway in adults with ADHD is unclear.
Single-photon emission computed tomography with [99mTC]TRODAT-1 was used to assess striatal dopamine transporter (DAT) availability. Event-related functional magnetic resonance imaging was conducted on subjects performing the Iowa Gambling Test.
DAT availability was found to be associated with the BOLD response, which was a covariate of monetary loss, in the medial prefrontal cortex (r = 0.55, P = .03), right ventral striatum (r = 0.69, P = .003), and right orbital frontal cortex (r = 0.53, P = .03) in adults with ADHD. However, a similar correlation was not found in the controls.
The results confirmed that dopaminergic tone may play a different role in the penalty-elicited response of adults with ADHD. It is plausible that a lower neuro-threshold accompanied by insensitivity to punishment could be exacerbated by the hypodopaminergic tone in ADHD.
The present study investigated the effects of glutamine (GLN) pretreatment on CD4+ T cell polarisation and remote kidney injury in mice with gut-derived polymicrobial sepsis. Mice were randomly assigned to three groups: normal control fed with American Institute of Nutrition (AIN)-93G diet and two sepsis groups provided with either AIN-93G-based diet or identical components, except part of casein was replaced by GLN. Mice were given their respective diets for 2 weeks. Then, mice in the sepsis groups were performed with caecal ligation and puncture and were killed 72 h after the surgery. Blood, spleens and kidneys were collected for further examination. The results showed that sepsis resulted in decreased circulating and splenic total T lymphocyte and CD4+ T cell percentages, whereas IL-4-, and forkhead box p3 (Foxp3)-expressing CD4+ T cells percentages were up-regulated. Compared with the sepsis control group, pretreatment with GLN maintained blood T and CD4+ T cells and reduced percentages of IL-4- and Foxp3-expressing CD4+ T cells. Also, a more pronounced activation and increased anti-apoptotic Bcl-2 gene expression of splenic CD4+ T cells were observed. Concomitant with the decreased plasma IL-6, keratinocyte-derived chemokine (KC) levels, the gene expression of KC, macrophage inflammatory protein-2 and renal injury biomarker kidney injury molecule-1 (Kim-1) were down-regulated when GLN was administered. These findings suggest that antecedent of GLN administration elicit a more balanced blood T helper cell polarisation, sustained T cell populations, prevented splenic CD4+ T cell apoptosis and attenuated kidney injury at late phase of polymicrobial sepsis. GLN may have benefits in subjects at risk of abdominal infection.
Anxiety disorders are prevalent yet under-recognized in late life. We examined the prevalence of anxiety disorders in a representative sample of community dwelling older adults in Hong Kong.
Data on 1,158 non-demented respondents aged 60–75 years were extracted from the Hong Kong Mental Morbidity survey (HKMMS). Anxiety was assessed with the revised Clinical Interview Schedule (CIS-R).
One hundred and thirty-seven respondents (11.9%, 95% CI = 10–13.7%) had common mental disorders with a CIS-R score of 12 or above. 8% (95% CI = 6.5–9.6%) had anxiety, 2.2% (95% CI = 1.3–3%) had an anxiety disorder comorbid with depressive disorder, and 1.7% (95% CI = 1–2.5%) had depression. Anxious individuals were more likely to be females (χ2 = 25.3, p < 0.001), had higher chronic physical burden (t = −9.3, p < 0.001), lower SF-12 physical functioning score (t = 9.2, p < 0.001), and poorer delayed recall (t = 2.3, p = 0.022). The risk of anxiety was higher for females (OR 2.8, 95% C.I. 1.7–4.6, p < 0.001) and those with physical illnesses (OR 1.4, 95% C.I. 1.3–1.6, p < 0.001). The risk of anxiety disorders increased in those with disorders of cardiovascular (OR 1.9, 95% C.I. 1.2–2.9, p = 0.003), musculoskeletal (OR 2.0, 95% C.I. 1.5–2.7, p < 0.001), and genitourinary system (OR 2.0, 95% C.I. 1.3–3.2, p = 0.002).
The prevalence of anxiety disorders in Hong Kong older population was 8%. Female gender and those with poor physical health were at a greater risk of developing anxiety disorders. Our findings also suggested potential risk for early sign of memory impairment in cognitively healthy individuals with anxiety disorders.
During 1997–2012 we conducted a nationwide camera-trapping survey and assessed the availability of prey and habitat for the clouded leopard Neofelis nebulosa in Taiwan. We surveyed 1,249 camera-trap sites over 113,636 camera-trap days, from the seashore to an altitude of 3,796 m and covering various types of vegetation. No clouded leopards were photographed during 128,394 camera-trap days, including at 209 sites in other studies, confirming the presumed extinction of clouded leopards in Taiwan. Assessment of the prey base revealed altitudinal distribution patterns of prey species and prey biomass. Areas at lower altitudes and with less human encroachment and hunting supported a higher prey biomass and more of the typical prey species of clouded leopards. Habitat analysis revealed 8,523 km2 of suitable habitat but this was reduced to 6,734 km2 when adjacent areas of human encroachment were subtracted. In the absence of hunting and large mammalian carnivores the major prey of clouded leopards in Taiwan, such as Formosan macaques Macaca cyclopis, Reeves's muntjacs Muntiacus reevesi, Formosan serow Capricornis swinhoei and sambar Rusa unicolor, could become over-abundant. Thus, it is important to address the cascading effect of the disappearance of top-down predator control. Our assessment indicated that, with proper regulation of hunting, habitat restoration and corridor improvement, it may be possible to reintroduce the clouded leopard.
This paper presents a robust reliability analysis method for systems of multimodular redundant (MMR) controllers using the method of partitioning and parallel processing of a Markov chain (PPMC). A Markov chain is formulated to represent the N distinct states of the MMR controllers. Such a Markov chain has N2 directed edges, and each edge corresponds to a transition probability between a pair of start and end states. Because N can be easily increased substantially, the system reliability analysis may require large computational resources, such as the central processing unit usage and memory occupation. By the PPMC, a Markov chain's transition probability matrix can be partitioned and reordered, such that the system reliability can be evaluated through only the diagonal submatrices of the transition probability matrix. In addition, calculations regarding the submatrices are independent of each other and thus can be conducted in parallel to assure the efficiency. The simulation results show that, compared with the sequential method applied to an intact Markov chain, the proposed PPMC can improve the performance and produce allowable accuracy for the reliability analysis on large-scale systems of MMR controllers.
Nature has evolved a palette of biological materials to address different structural requirements such as:
The intricate and ingenious hierarchical structure is responsible for the outstanding performance. Toughness is conferred by the presence of controlled interfacial features, buckling resistance can be achieved by filling a slender column with a lightweight foam, and armor protection is accomplished by small dermal plates with unique attachment arrangements, resulting in controlled and prescribed flexibility. In Chapters 6–10 we present and interpret selected examples of biological materials. In addition to the structural requirements, there are also functional requirements such as adhesion and optical properties.
The number of elements and compounds that can be synthesized at ambient temperature and in aqueous environments is limited, and therefore the architecture of the structure is of utmost importance.
We introduce the different classes of biological materials in these chapters, following the Wegst–Ashby classification. These were defined in Chapter 2 (Fig. 2.11) as:
It is a misunderstanding to think that the ultimate goal of biomimetics is to reproduce living organisms. There are essential differences, as we list in the following.
(a) Organisms are composed of cells (in the case of humans, 1013 of them). They direct a great deal of the activity. As seen in Chapter 4, each mammalian cell contains 10 000 different proteins, for a total of 500 million. There are numerous types of cells in each organism, and they have complex lives.
(b) Organisms are, for the most part, composed of a limited number of elements: C, Ca, H, O, P, N, and S. Synthetic materials have, on the other hand, a cornucopia of elements, made possible by the synthesis and processing techniques developed by humans.
What we try to do is to emulate the design and assembly principles used in natural materials. In this book we have seen many examples where superior properties are obtained through a hierarchical design and ingenious solutions. Bone, nacre, and dentin have toughnesses significantly superior to those of the mineral constituents, hydroxyapatite and calcium carbonate. Silk reaches strengths higher than 1 GPa using the weak hydrogen bond, through the existence of nano-scale β-sheet crystals with proper dimensions. Bioinspiration requires identification, understanding, and quantification of natural design principles and their replication in synthetic materials, taking into account the intrinsic properties (Studart, 2012). This approach is being pursued not only for structural materials, but also for functional materials and devices. The areas of sensing, optics, architecture, and robotics are exploring biological solutions.
Taking a unique materials science approach, this text introduces students to the basic concepts and applications of materials and biomedical engineering and prepares them for the challenges of the new interdisciplinary field of biomaterials science. Split into three sections - Basic Biology Principles, Biological Materials, and Bioinspired Materials and Biomimetics - it presents biological materials along with the structural and functional classification of biopolymers, bioelastomers, foams, and ceramic composites. More traditional biomimetic designs such as Velcro are then discussed in conjunction with new developments that mimic the structure of biological materials at the molecular level, mixing nanoscale with biomolecular designs. Bioinspired design of materials and structures is also covered. Focused presentations of biomaterials are presented throughout the text in succinct boxes, emphasising biomedical applications, whilst the basic principles of biology are explained, so no prior knowledge is required. The topics are supported by approximately 500 illustrations, solved problems, and end-of-chapter exercises.
Hydroxylapatite or hydroxyapatite (HAP) is a calcium-phosphate-based mineral of the apatite family. Its chemical formula is Ca10(PO4)6(OH)2. It can be found widely in nature and is the major component of bone, enamel, and dentin in teeth, antler, ganoid fish scales (in alligator gar and Senegal bichir), turtle shells, and armadillo and alligator osteoderms. It exists in minute quantities in the brain (brain sand), without significantly affecting its function. Thus, the expression “having sand in the head” is not without reason. The density of HAP is 3.15 g/cm3. Nonstoichiometric minerals can exist with Ca10(PO4)6(OH, F, Cl, Br)2; if the OH group is replaced by F it is called fluoroapatite; if it is replaced by Cl, it is called chloroapatite. It can be occasionally used as a gem, and the cat’s eye is a commonly known use.
In this chapter, we will concentrate on bone and teeth with emphasis on their structure and mechanical properties. They are HAP–collagen composites and their mechanical properties are the result of the complex interplay and hierarchy built by these structures. Selected calcium-phosphate-based bony tissues with unique functionalities, such as antler, turtle shells, alligator osteoderms, and fish scales, will also be described in the second part of this chapter.
The ultimate goal for a materials engineer is to learn from the lessons of nature and to apply this knowledge to new materials and design. This is not a new quest, and humans have sought inspiration from nature since prehistory. The early materials used by humans were primarily natural: stones, bones, wood, skins, bark. The accelerating pace of the civilizing process has been attributed to the introduction of new synthetic materials; thus, the bronze and iron ages followed the stone age. We have now entered the brave new world of the silicon age, which is bound to produce unimaginable change. Homo silicensis, connected 24/7 to computerized contraptions, can already be seen on campuses and elite coffee houses, sipping lattes.
The constant quest for new materials and designs is leading us to a systematic inquiry of nature in order to unravel its secrets. This is the field of biomimetics, and VELCRO® is the standard example of bioinspired design. It is inspired by the burrs of plants that contain small hooks that attach themselves to animal wool or our clothes.
The quest to mimic nature is now reaching a new chapter. Whereas in the past, structural and functional characteristics served as inspiration for designs and materials, with attention given to mesoscopic and, perhaps, microscopic aspects, the arsenal of new experimental techniques and computational methods is descending to the nanometer scale. This is the scale at which atoms assemble into molecules, and molecules form molecular arrangements such as DNA, RNA, plasmids, and proteins.
Prominent characterization techniques available to modern researchers are (e.g. Gronau et al., 2012):
transmission and scanning electron microscopy at higher and higher resolutions;