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We report our efforts toward 3D printing of polyether ether ketone (PEEK) at room temperature by direct-ink write technology. The room-temperature extrusion printing method was enabled by a unique formulation comprised of commercial PEEK powder, soluble epoxy-functionalized PEEK (ePEEK), and fenchone. This combination formed a Bingham plastic that could be extruded using a readily available direct-ink write printer. The initial green body specimens were strong enough to be manipulated manually after drying. After printing, thermal processing at 230 °C resulted in crosslinking of the ePEEK components to form a stabilizing network throughout the specimen, which helped to preclude distortion and cracking upon sintering. A final sintering stage was conducted at 380 °C. The final parts were found to have excellent thermal stability and solvent resistance. The Tg of the product specimens was found to be 158 °C, which is 13 °C higher than commercial PEEK as measured by DSC. Moreover, the thermal decomposition temperature was found to be 528 °C, which compares well against commercial molded PEEK samples. Chemical resistance in trifluoroacetic acid and 8 common organic solvents, including CH2Cl2 and toluene, were also investigated and no signs of degradation or weight changes were observed from parts submerged for 1 week in each solvent. Test specimens also displayed desirable mechanical properties, such as a Young’s modulus of 2.5 GPa, which corresponds to 63% of that of commercial PEEK (reported to be 4.0 GPa).

Additive manufacturing (AM) technologies are expanding the boundaries of materials science and providing an exciting forum for interdisciplinary research. The ability to fabricate arbitrarily complex objects has made AM technologies indispensable in personalized healthcare, soft electronics, and renewable energy. At the intersection of AM technologies and materials chemistry are stimuli-responsive polymers, which change their chemical and physical properties in response to specific environmental cues. The responsiveness of these “smart” polymers makes them suitable for AM and provides functionality to the additively manufactured objects. Furthermore, the type and degree of stimulus response of smart polymers can be regulated through precise synthetic design or via incorporation of additives. Herein, we review recently reported stimuli-responsive polymers used in AM, with a focus on the design and chemistry of the polymers. The materials are broadly classified by type of printing, and more specifically classified by type of stimulus response. Finally, we briefly consider existing challenges that stimuli-responsive materials in AM can address in the future.

Objective Lack of knowledge about a disease could impede early diagnosis and may lead to delays in seeking appropriate medical care. The aim of this study was to explore knowledge of dementia (KOD) and to find the determinants of KOD among three groups: older adults with normal cognition, mild cognitive impairment (MCI), and dementia. Methods A representative nationwide sample of 6141 Korean elders aged 65 years or older participated in face-to-face interviews and answered 14 questions pertaining to general information, etiology, symptoms, and treatment of dementia. Stepwise multiple regressions and path analyses probed the relationships between various sociodemographic variables and KOD. Results The percentage of correct responses was only 62%. The item ‘A person who remembers things that happened in the past does not have dementia’ was answered correctly (false) by only 24.8–27% of the respondents in all groups. Older adults with normal cognition had higher KOD scores than those with MCI or dementia. In the normal-cognition group, KOD scores were higher among highly educated, younger, and literate women with no depression and a family history of dementia. In contrast with the determinants in the normal-cognition group, only the ability to read and write predicted KOD scores in the dementia group. Conclusions Efforts to enhance KOD in elder adults are needed. Public education regarding the differences between dementia and healthy aging may increase KOD among normal elders and those with MCI. Among elders with dementia, educational materials that do not require literacy may be more helpful in increasing KOD with the aim of preventing treatment delay.

Although sub-regional analysis methods of the corpus callosum (CC) have been developed, there has been no in vivo magnetic resonance imaging (MRI) study on a sub-regional volume analysis of the CC of late-onset depression (LOD). The aim of this study was to investigate the CC volume differences between LOD subjects and healthy elderly controls using a sub-regional analysis technique. Forty subjects with LOD and thirty nine group-matched healthy control subjects underwent 3T MRI scanning, and sub-regional volumes of the CC were measured and compared between the groups. The volumes of total (F=5.8, p=0.001), the anterior (F=5.2, p=0.001) and the posterior CC (F=5.1, p=0.001) were significantly reduced in the LOD group as compared to the control group. We measured cognitive functions in several different domains (language functions, verbal learning, visuospatial functions, delayed recall, memory consolidation, recognition memory, and executive functions) through the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease. The anterior CC volume in the LOD group showed significant positive correlation with the Verbal Fluency scores. The posterior CC volume in the LOD group was positively correlated significantly with the Word List Memory, the Word List Recall and the Constructional Praxis scores. This study is the first to elaborate the sub-regional volume differences of the CC between controls and LOD patients. These structural changes in the CC might be at the core of the underlying neurobiological mechanisms in LOD.

Background: Few studies have investigated the role of protective factors for suicidal ideation, which include resilience and social support among psychiatric patients with depression and/or anxiety disorders who are at increased risk of suicide. Methods: Demographic data, history of childhood maltreatment, and levels of depression, anxiety, problematic alcohol use, resilience, perceived social support, and current suicidal ideation were collected from a total of 436 patients diagnosed with depression and/or anxiety disorders. Hierarchical multiple logistic regression analyses were used to identify the independent and interaction effects of potentially influencing factors. Results: Moderate-severe suicidal ideation was reported in 24.5% of our sample. After controlling for relevant covariates, history of emotional neglect and sexual abuse, low resilience, and high depression and anxiety symptoms were sequentially included in the model. In the final model, high depression (adjusted odds ratio (OR) = 9.33, confidence interval (CI) 3.99–21.77) and anxiety (adjusted OR = 2.62, CI = 1.24–5.53) were independently associated with moderate-severe suicidal ideation among risk factors whereas resilience was not. In the multiple logistic regression model that examined interaction effects between risk and protective factors, the interactions between resilience and depression (p

This study aimed to validate the TICS and modified TICS (TICSm) in Korean elderly population and to compare MCI and dementia screening ability between TICS and TICSm. TICS and TICSm were administered to 70 cognitively normal (CN), 75 MCI, and 85 dementia subjects, with mini-mental state examination (MMSE) and other cognitive and functional measures. TICS and TICSm scores were highly correlated with other global cognitive and functional scores. The CN vs. dementia discrimination ability of both instruments was as excellent as that of MMSE (sensitivity/specificity at optimal cutoff: 87.1/90.1 for TICS; 88.2/90.0 for TICSm). Although their CN vs. MCI discrimination performances were comparable to that of MMSE, they were far from perfect (sensitivity/specificity: 69.3/68.6 for TICS; 73.3/67.1 for TICSm). There was no significant difference in dementia or MCI screening accuracy between TICS and TICSm. Both of them also showed high test-retest reliability. Our findings indicate that TICS and TICSm are reliable and as valid as MMSE in regard of screening cognitively impaired elderly. In terms of the comparison between TICSm and TICS, however, TICSm has little advantage over TICS for screening dementia and even MCI, in spite of longer administration time and more efforts required.

This study aimed to find the most sensitive brain region of APP-PS1 mice in early-stage Alzheimer's disease (AD) and to compare the findings with wild-type mouse brain using (1)H high resolution magic angle spectroscopy (HR-MAS). At 18 and 35 weeks of age, the object recognition test was performed with both APP-PS1 and wild-type mice, and the metabolite concentrations were measured in six brain regions at 38-42 weeks using (1)H HR-MAS. Compared to that of wild-type mice, the memory index of the APP-PS1 mice at 18 weeks was not significantly different; however, the memory index of the APP-PS1 mice at 35 weeks was significantly lower. Similar to the results of the (1)H HR-MAS, the [N-acetyl aspartate (NAA)+acetate (Acet)] level in APP-PS1 mice was decreased in the hippocampus and temporal cortex, and the myo-inositol (mIns) level was increased in the entire brain. In addition, scyllo-inositol (sIns) was also elevated in the frontal, occipital, and parietal cortices, hippocampus and thalamus. These findings demonstrated that the behavioral abnormalities of the APP-PS1 mice started at about 30 weeks of age and that the hippocampus and temporal cortex were the most sensitive regions during early-stage AD. In addition, the results of this study confirmed that an increase of mIns and sIns precedes the reduction of the NAA level. These findings demonstrated that the metabolism of the APP-PS1 mouse was associated with early-stage AD. Furthermore, the regional neurochemical profile of APP-PS1 mouse can be used to investigate the pathophysiological mechanisms associated with AD.

A facile approach to prepare thiol-terminated poly(styrene-ran-vinyl phenol) (PSVPh) copolymers and PSVPh-coated gold nanoparticles is reported with the goal of creating stabilizing ligands for nanoparticles with controlled hydrophilicity. Dithioester-terminated poly(styrene-ran-acetoxystyrene) copolymers were synthesized via RAFT polymerization using cumyl dithiobenzoate as a chain transfer agent. These copolymers were converted to thiol-terminated PSVPh copolymers by a one step hydrazinolysis reaction using hydrazine hydrate to simultaneously convert dithioester-terminal and acetoxy-pendant groups to thiol-terminal and hydroxyl-pendant groups, respectively. Spectroscopic observations including NMR and IR confirm end- and pendant-group conversion. PSVPh-coated gold nanoparticles were synthesized in the presence of a mixture of thiol-terminated PSVPh and PSVPh copolymers containing disulfides as stabilizing ligands in a water/toluene, two-phase system. The size and size distribution of core gold nanoparticles were determined by TEM and image analysis. The hydrodynamic radius of PSVPh-coated gold nanoparticles was also determined by dynamic light scattering experiment, which confirms the particle analysis by TEM. This procedure provides a facile technique to control the polarity and hydrophilicity of metal nanoparticle surfaces and could prove critical in advancing the control of nanoparticle placement in biological and hierarchically ordered systems, such as diblock copolymers.

The magnetic field has been regarded as both harmful and beneficial for its applications on human brains including transcranial magnetic stimulation (TMS), but its effects still remain in question. Here, we determined using single photon emission computed tomography (SPECT) if 0.3-T static magnetic field could alter regional cerebral blood flow (rCBF) in target and other brain regions in healthy subjects. The permanent static magnet (0.3 T, unipolar, disk shaped, 4 cm diameter and 1 cm thick) was placed on the right frontotemporal region of the brain for each of 14 healthy subjects. Tc-99m ECD perfusion SPECT was taken to compare the CBF patterns in the subjects exposed to the static magnet field with those of the resting and sham conditions. We found that the rCBF was significantly increased in the right frontal and parietal regions and the right insula. On the other hand, rCBF was rather decreased in the left frontal and left parietal regions (P

Gold-catalyzed reactions of 3-silyloxy-1,4-enynes with alcohols afford primary, secondary, and tertiary pent-2-en-4-ynyl ethers in moderate to excellent yields. The substitution proceeds with high regioselectivity. An initial cyclization providing five-membered carbocycles instead was not observed under the reaction conditions. Control experiments show that these reactions are also catalyzed by Bronsted- and Lewis-acids, although scope and yields are markedly reduced.

Objectives: Functional MRI (fMRI) has become an important imaging modality for analyzing the neural mechanisms underlying schizophrenia. Earlier studies indicate that patients with schizophrenia tend to generate involuntary and unnecessary head motion during visual tasks. Since head motion can deteriorate the quality of fMRI data, an investigation was needed to examine the type and extent of head motion from patients with schizophrenia undergoing fMRI. Methods: Patients with schizophrenia and demographically-matched healthy comparison subjects underwent fMRI examination involving visual working memory tasks. We obtained head movement parameters (three translational and three rotational) through mathematical realignment of the volumetric image data, and transformed these parameters into head displacement indices to quantify the subject's head motion in space. Results: We found no group difference in displacement indices between the two groups. Group comparison of movement parameters indicated that the patient group showed reduced head motion along the superior–inferior direction when compared to healthy individuals. Conclusion: These results suggest that cognitive fMRI examination in patients with schizophrenia can be successfully conducted without the deteriorative effects of head motion.

This study measured the cerebral glucose metabolism in patients suffering from corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). The aim was to determine if there is a different metabolic pattern using (18)F-labeled 2-deoxyglucose ((18)F-FDG) positron emission tomography (PET). The regional cerebral glucose metabolism was examined in 8 patients diagnosed clinically with CBD (mean age 69.6 +/- 7.8 years; male/female: 5/3), 8 patients with probable PSP (mean age 67.8 +/- 4.5 years; male/female: 4/4) and 22 healthy controls. The regional cerebral glucose metabolism between the three groups was compared using statistical parametric mapping (SPM) with a voxel-by-voxel approach (p < 0.001, 200-voxel level). Compared with the normal controls, asymmetry in the regional glucose metabolism was observed in the parietal, frontal and cingulate in the CBD patients. In the PSP patients, the glucose metabolism was lower in the orbitofrontal, middle frontal, cingulate, thalamus and mid-brain than their age matched normal controls. A comparison of the two patient groups demonstrated relative hypometabolism in the thalamus, the mid-brain in the PSP patients and the parietal lobe in CBD patients. These results suggest that when making a differential diagnosis of CBD and PSP, voxel-based analysis of the (18)F-FDG PET images using a SPM might be a useful tool in clinical examinations.

With the Korean population rapidly aging and the number of Koreans with Alzheimer's disease(AD) steadily growing, treatment of AD is becoming an increasing concern. Galantamine hydrobromide, a dual acetylcholinesterase inhibitor and allosteric modulator of nicotinic receptors, is being studied in the treatment of the disease.This study compared the efficacy and tolerability of 3 doses of galantamine in a Korean population with mild to moderate AD.In this prospective, multicenter, double-blind, community-controlled, comparative study, patients with mild to moderate AD were randomized to receive galantamine 8, 16, or 24 mg/d; patients were evaluated at baseline (week 0) and after 4, 8, and 16 weeks of treatment. A 4-week dose-titration schedule was used in the 16-and 24-mg/d groups. Also included were patients with AD from a community control group who were untreated and assessed at baseline and week 16. The primary efficacy outcome was change in cognitive function, as measured with the Korean version of the AD Assessment Scale-11-item cognitive subscale (ADAS-cog/11-K); secondary efficacy measures included changes in functional capacity, behavioral symptoms, and global impression (clinical response), as measured with the Korean versions of the Disability Assessment for Dementia Scale (DAD-K), Behavior Pathology in AD Rating Scale (BEHAVE-AD-K), and Clinician's Interview-Based Impression of Change plus Caregiver Input (CIBIC-plus-K).A total of 300 patients (228 women, 72 men) were enrolled (76, 78, 80, and 66 patients in the 8-, 16-,24-mg/d and community control groups, respectively). Significant differences in demographic characteristics were found between the galantamine and community control groups for age, sex, and duration of formal education (P = 0.042, P = 0.049, and P0.001, respectively). Results demonstrated a robust dose-response relationship between ADAS-cog/11-K and galantamine dosage compared with baseline and controls at 16 weeks. Mean (SE) improvements ranged from 3.7 (0.8) to 5.6 (0.8) points in the galantamine groups, whereas the control group deteriorated by 4.7 (0.5) points (P0.001). Similarly, significant improvements in all 3 treatment groups were observed in mean DAD-K, BEHAVE-AD-K, and CIBIC-plus-K scores (P0.001, P0.005, and P0.001, respectively). Galantamine was relatively well tolerated.This study found that galantamine effected significant benefits on the cognitive, functional, and behavioral symptoms of mild to moderate AD in this population of Korean patients. The tolerability results suggest that galantamine is well tolerated in these patients. Inc.

We describe a method of interactive three-dimensional segmentation and visualization for anatomical magnetic resonance imaging (MRI) data in a personal computer environment. The visual feedback necessary during 3-D segmentation was provided by a ray casting algorithm, which was designed to allow users to interactively decide the visualization quality depending on the task-requirement. Structures such as gray matter, white matter, and facial skin from T1-weighted high-resolution MRI data were segmented and later visualized with surface rendering. Personal computers with central processing unit (CPU) speeds of 266, 400, and 700 MHz, were used for the implementation. The 3-D visualization upon each execution of the segmentation operation was achieved in the order of 2 s with a 700 MHz CPU. Our results suggest that 3-D volume segmentation with semi real-time visual feedback could be effectively implemented in a PC environment without the need for dedicated graphics processing hardware.

Structural MRI findings of abnormalities in the prefrontal cortex in schizophrenia and affective disorder have been inconsistent likely due to small, heterogeneous samples, the evaluation of prefrontal gray and white matter combined, and the fact that prefrontal cortex is typically not delineated into separate gyri (e.g., Shenton et al., 2001; Strakowski et al., 2002). We previously reported smaller prefrontal gray matter in first-episode schizophrenia relative to first-episode affective psychosis and controls (Hirayasu et al., 2001). One unresolved question in the literature is whether or not further volume reduction will be observed over time, the focus of this report. Prefrontal gray and white matter volumes were measured (see Fig. 1) in patients at the time of first hospitalization for schizophrenia (n=12, 3 females) or affective psychosis (n=10, 1 female, 9 bipolar, 1 unipolar), and psychiatrically well subjects (n=15, 1 female). Subjects were rescanned approximately 1.5 years later. Seven schizophrenia, six affective, and four comparison subjects were previously described solely at first scan (Hirayasu et al., 2001). Samples did not differ in age (28.1±8.4; 22.9±2.8; 25.4±4.5; F(2,34)=2.2, p=0.12) or WAIS Information scores (11.8±3.4; 12.2±3.1, 11.8±2.0; F(2.32)=0.6, p=0.9), nor in parental socioeconomic status (F(2.34)=2.32, p=0.11) or handedness (F(2.33)=1.6, p=0.22). BPRS scores were higher in schizophrenics (41.2±13.2) than affectives (33.8±8.0) (F(1,20)=5.71, p=0.027). Similar neuroleptics were prescribed for the patient groups (schizophrenics: 7 typical, 4 atypical, 1 none; affectives: 6 typical, 3 atypical, 1 none). Fig. 1 Prefrontal ROI definitions and volumes. (a) Coronal slice, (b) axial slice showing prefrontal gray and white matter, and (c) three. Three-dimensional reconstruction of the extent of gray and white matter boundaries. MR images were acquired with a 1.5-T ... Relative volumes [i.e., absolute volumes divided by intracranial contents (ICC)] were used in the analyses. Repeated-measures ANOVA was performed with diagnosis as the between-subjects factor and time and side as the within-subjects factors for gray and white matter separately. Prefrontal gray matter at time 1 was significantly different among groups (F2,30=5.56, p=0.009), with schizophrenics smaller than controls and affectives, who did not differ from each other. There was no interaction for group by time by side for prefrontal gray matter (F2,34=0.65, p=0.53). All groups showed larger gray matter on the left (F2,30=8.72, p=0.006). White matter volumes did not differ among groups (p>0.87), and all groups showed more white matter on the right (F1,30=39.20, p

Membrane phospholipid abnormalities have been proposed to be involved in the pathogenesis of schizophrenia. Cytosolic phospholipase A2 (cPLA2) plays a major role in the metabolism of fatty acids but is also found in abnormalities in patients with schizophrenia. This study examined the association between the cPLA2 gene BanI polymorphism and schizophrenia. Ninety-seven Korean schizophrenia patients and 117 healthy controls participated in this study. Genotyping was performed by using polymerase chain reaction (PCR)-based methods. Genotype and allele distributions were significantly different between the schizophrenia patients and controls. In particular, the A2 allele was associated with an increased risk of schizophrenia (p=0.003; odds ratio (OR)=1.799; confidence interval (CI)=1.192–2.716). However, the polymorphism was not different when the patient group was subdivided by the presence or absence of family history and by positive and negative subgroups according to the positive and negative syndrome scale (PANSS) score on schizophrenia. The results of this study replicated those of previous findings from Western countries and indicates the need for further studies on the potential role of the cPLA2 gene polymorphism in the susceptibility to schizophrenia.