Redox-Active Heteroatom-Functionalized Polyacetylenes.

The discovery of metallic conductivity in polyacetylene [-HC=CH-]n upon doping represents a landmark achievement. However, the insolubility of polyacetylene and a dearth of methods for its chemical modification have limited its widespread use. Here, we employ a ring-opening metathesis polymerization (ROMP) protocol to prepare functionalized polyacetylenes (fPAs) bearing: (1) electron-deficient boryl (-BR2 ) and phosphoryl (-P(O)R2 ) side chains; (2) electron-donating amino (-NR2 ) groups, and (3) ring-fused 1,2,3-triazolium units via strain-promoted Click chemistry. These functional groups render most of the fPAs soluble and can lead to intense light absorption across the visible to near-IR region. Also, the presence of redox-active boryl and amino groups leads to opposing near-IR optical responses upon (electro)chemical reduction or oxidation. Some of the resulting fPAs show greatly enhanced air stability when compared to known polyacetylenes. Lastly, these fPAs can be cross-linked to yield network materials with the full retention of optical properties.

Water-Assisted Transfer Patterning of Nanomaterials.

We introduce a straightforward and cost-effective water-assisted approach to transfer patterns of nanomaterials onto diverse substrates. The transfer method relies on the hydrophobic effect and utilizes a water-soluble polymer film as a carrier to transfer hydrophobic nanomaterials from a patterned source substrate onto a target substrate. Using this approach, nanomaterials are transferred readily from solutions onto surfaces of various shapes and compositions with high fidelity for feature sizes approaching 10 microns.

Doppler images of intrapulmonary arteries within atelectasis and its impact on right ventricular afterload with transesophageal echocardiography.

Video-assisted thoracoscopy (VATS) cardiac surgery requires one-lung ventilation (OLV) and transoesophageal ultrasound (TOE) monitoring. Colour and spectral Doppler make it possible to study the pattern of blood flow in the pulmonary vessels within the atelectatic lung. In this case report we describe how TOE can be used to detect blood flow within the atelectatic lung and to assess pulmonary vascular resistance (PVR) and right ventricular (RV) afterload. FINDINGS: Three anaesthetised, mechanically ventilated adults scheduled for cardiac surgery by VATS were scanned with TOE. After left OLV, the transducer was rotated away from the heart to obtain 2D colour Doppler images of blood flow within the consolidated lung parenchyma. We were able to identify the flow pattern of the intrapulmonary branches of the pulmonary artery. PVR was recorded using pulsed cardiac Doppler at baseline, after induction of general anaesthesia, 20 min after OLV and at the end of OLV, and after performing an alveolar recruitment manoeuvre (ARM) that led to complete resolution of the aforementioned consolidation. CONCLUSIONS: TOE is a semi-invasive imaging tool that can be used to diagnose and study PVR-induced atelectasis and to analyse the resulting pulmonary shunt and its possible effect on PVR.

Not all silicon quantum dots are equal: photostability of silicon quantum dots with and without a thick amorphous shell.

Luminescent colloidal silicon quantum dots (SiQDs) are sustainable alternatives to metal-based QDs for various optical applications. While the materials are reliant on their photoluminescence efficiency, the relationship between the structure and photostability of SiQDs is yet to be well studied. An amorphous silicon (a-Si) shell was recently discovered in SiQDs prepared by thermally-processed silicon oxides. As a-Si is known as a source of defects upon UV irradiation, the disordered shell could potentially have an adverse effect on the optical properties of nanoparticles. Herein, the photostability of ∼5 nm diameter SiQDs with an amorphous shell was compared with that of over-etched SiQDs of equivalent dimensions that bore an a-Si shell of negligible thickness. An UV-induced degradation study was conducted by subjecting toluene solutions of SiQDs to 365 nm light-emitting diodes (LEDs) under an inert atmosphere for predetermined times up to 72 hours. The structure, composition, and optical responses of the exposed SiQDs were evaluated.

Spectrotemporal characterization of photoluminescent silicon nanocrystals and their energy transfer to dyes.

Silicon nanocrystals (SiNCs) are a promising material for applications in bioanalysis and imaging. Compared to other types of semiconductor nanocrystals, the development and characterization of energy transfer (ET) configurations with SiNCs has been far more limited, resulting in an equally limited understanding of this process and its SiNC-specific nuances. Here, we present a systematic and detailed study of ET between SiNCs and dyes. A combination of spectroelectrophoresis and time-gated and time-resolved photoluminescence measurements were used to characterize the photophysical properties of ensembles of SiNCs and gain insight into how these properties varied as a function of nanocrystal size. ET between SiNC donors and a series of non-fluorescent Black Hole Quencher (BHQ) dyes and fluorescent sulfo-Cyanine 5.5 dye acceptors was evaluated in terms of spectral properties, wavelength-resolved efficiencies, trends with spectral overlap integral, and differences between two methods of BHQ association with the SiNCs. The overall results were consistent with a Förster resonance energy transfer (FRET) mechanism where the polydispersity of the SiNCs had a significant impact on the observed ET: the choice of wavelength and timing parameters were important, and ensemble measurements represented an average of heterogeneous ET behaviors. Prospective advantages and disadvantages of SiNCs as ET donors are discussed. This study serves as a foundation for the continued and optimized development of ET configurations with SiNCs.

Association of suicidal ideation and depression with the use of proton pump inhibitors in adults: a cross-sectional study.

Proton pump inhibitors (PPIs) were found to be associated with depression. This study aimed to find the cross-sectional association between recent PPI use and suicidal ideation. Item 9 of Patient Health Questionnaire-9 (PHQ-9) of the US National Health and Nutrition Examination Survey (NHANES) between 2005 and 2018 was used to categorize whether or not the participants had suicidal ideation. The secondary outcome of this study was depression and the scores of the PHQ-9 were used as the depression diagnostic instrument. The study population included 16,881 participants who were over 20 years old. The bivariate Rao-Scott χ2 test showed a significant association between PPI use and suicidal ideation (P < 0.001) and a stronger association was observed between PPIs and depression (P < 0.001). Multiple logistic regression analysis of the education, gender, race and age-adjusted model revealed that the PPI users had a 2.34 (95% CI 1.66-3.31) greater risk of having suicidal ideation than the non-PPI users. Middle-aged participants (40-49 years) showed the greatest number of differences in suicidal ideation between PPI and non-PPI users (P < 0.001). Future research should continue to consider the psychiatric effects of taking PPIs.

Regional disparity in epidemiological characteristics of adolescent scoliosis in China: Data from a screening program.

Objective: We investigated regional disparities in rates of scoliosis among adolescents in western and eastern China and the dominant factors underlying these disparities. Methods: This cross-sectional study used data from a school scoliosis screening program conducted in two typical areas: Yangpu District of Shanghai (eastern China) and Tianzhu Tibetan Autonomous County of Gansu Province (western China), during October 2020 to February 2021. Participants included adolescents aged 12-16 years (4,240 in Shanghai and 2,510 in Gansu Province). School scoliosis screening data were obtained on age, sex, height, weight and BMI, and region as well. We screened angles of trunk rotation in level of proximal thoracic (T1-T4), main thoracic (T5-T12), and lumbar (T12-L4) by the forward bend test with scoliometer. An angle of trunk rotation ≥5° was used as the criterion to identify suspected scoliosis. Results: The proportion of suspected scoliosis was lower in Shanghai (6.9%) than in Gansu (8.6%). Angle of trunk rotation tended to increase with age in Shanghai, peaking at 15 years, but decreased with age in Gansu, and bottomed at 15 years. The angle of trunk rotation in the proximal thoracic, main thoracic, and lumbar part of the spine appeared to be larger in Gansu adolescents and in Shanghai female adolescents. Age was a relevant factor in angle trunk rotation in regression models and interacted with region as well. Conclusion: We found regional and age- and sex-related disparities in rates of suspected scoliosis.

Silicon Surface Passivation for Silicon-Colloidal Quantum Dot Heterojunction Photodetectors.

Sensitizing crystalline silicon (c-Si) with an infrared-sensitive material, such as lead sulfide (PbS) colloidal quantum dots (CQDs), provides a straightforward strategy for enhancing the infrared-light sensitivity of a Si-based photodetector. However, it remains challenging to construct a high-efficiency photodetector based upon a Si:CQD heterojunction. Herein, we demonstrate that Si surface passivation is crucial for building a high-performance Si:CQD heterojunction photodetector. We have studied one-step methyl iodine (CH3I) and two-step chlorination/methylation processes for Si surface passivation. Transient photocurrent (TPC) and transient photovoltage (TPV) decay measurements reveal that the two-step passivated Si:CQD interface exhibits fewer trap states and decreased recombination rates. These passivated substrates were incorporated into prototype Si:CQD infrared photodiodes, and the best performance photodiode based upon the two-step passivation shows an external quantum efficiency (EQE) of 31% at 1280 nm, which represents a near 2-fold increase over the standard device based upon the one-step CH3I passivated Si.

Tailoring B-doped silicon nanocrystal surface chemistry via phosphorus pentachloride - mediated surface alkoxylation.

Doped silicon nanocrystals (SiNCs) are promising materials that could find use in a wide variety of applications. Realizing methods to tailor the surface chemistry of these particles offers greater tunability of the material properties as well as broader solvent compatibility. Herein, we report organic-soluble B-doped SiNCs prepared via a thermal processing method followed by phosphorus pentachloride etching induced functionalization with alkoxy ligands of varied chain lengths. This approach provides a scalable route to solution processable B-doped SiNCs and establishes a potential avenue for the functionalization of other doped SiNCs.

Silicon Quantum Dot-Polymer Fabry-Pérot Resonators with Narrowed and Tunable Emissions.

Luminescent silicon nanoparticles have been widely recognized as an alternative for metal-based quantum dots (QDs) for optoelectronics partly because of the high abundance and biocompatibility of silicon. To date, the broad photoluminescence line width (often >100 nm) of silicon QDs has been a hurdle to achieving competitive spectral purity and incorporating them into light-emitting devices. Herein we report fabrication and testing of straightforward configuration of Fabry-Pérot resonators that incorporates a thin layer of SiQD-polymer hybrid/blend between two reflective silver mirrors; remarkably these devices exhibit up-to-14-fold narrowing of SiQD emission and achieve a spectral bandwidth as narrow as ca. 9 nm. Our polymer-based, SiQD-containing Fabry-Pérot resonators also provide convenient spectral tunability, can be prepared using a variety of polymer hosts and substrates, and enable rigid as well as flexible devices.

"Turning the dials": controlling synthesis, structure, composition, and surface chemistry to tailor silicon nanoparticle properties.

Silicon nanoparticles (SiNPs) can be challenging to prepare with defined size, crystallinity, composition, and surface chemistry. As is the case for any nanomaterial, controlling these parameters is essential if SiNPs are to realize their full potential in areas such as alternative energy generation and storage, sensors, and medical imaging. Numerous teams have explored and established innovative synthesis methods, as well as surface functionalization protocols to control these factors. Furthermore, substantial effort has been expended to understand how the abovementioned parameters influence material properties. In the present review we provide a commentary highlighting the benefits and limitations of available methods for preparing silicon nanoparticles as well as demonstrations of tailoring optical and electronic properties through definition of structure (i.e., crystalline vs. amorphous), composition and surface chemistry. Finally, we highlight potential opportunities for future SiNP studies.

Widespread neocortical abnormalities in temporal lobe epilepsy with and without mesial sclerosis.

PURPOSE: Extrafocal structural abnormalities have been consistently described in temporal lobe epilepsy (TLE) with mesial temporal lobe sclerosis (TLE-MTS). In TLE without MTS (TLE-no) extrafocal abnormalities are more subtle and often require region of interest analyses for their detection. Cortical thickness measurements might be better suited to detect such subtle abnormalities than conventional whole brain volumetric techniques which are often negative in TLE-no. The aim of this study was to seek and characterize patterns of cortical thinning in TLE-MTS and TLE-no. METHODS: T1 weighted whole brain images were acquired on a 4 T magnet in 66 subjects (35 controls, 15 TLE-MTS, 16 TLE-no). Cortical thickness measurements were obtained using the FreeSurfer software routine. Group comparisons and correlation analyses were done using the statistical routine of FreeSurfer (FDR, p=0.05). RESULTS: TLE-MTS and TLE-no showed both widespread temporal and extratemporal cortical thinning. In TLE-MTS, the inferior medial and posterior temporal regions were most prominently affected while lateral temporal and opercular regions were more affected in TLE-no. The correlation analysis showed a significant correlation between the ipsilateral hippocampal volume and regions of thinning in TLE-MTS and between inferior temporal cortical thickness and thinning in extratemporal cortical regions in TLE-no. CONCLUSION: The pattern of thinning in TLE-no was different from the pattern in TLE-MTS. This finding suggests that different epileptogenic networks could be involved in TLE-MTS and TLE and further supports the hypothesis that TLE-MTS and TLE-no might represent two distinct TLE syndromes.

Titin-cap (TCAP) polymorphisms associated with marbling score of beef.

Marbling score (MS) is the major qualitative trait that affects carcass quality in beef cattle. In this study, we examined the association between genetic polymorphisms of the titin-cap gene (TCAP) and carcass traits in Korean native cattle (also known as Hanwoo). By direct DNA sequencing in 24 unrelated Korean cattle, we identified five sequence variants in 1.2kb of TCAP. Among them, four common polymorphic sites were selected for genotyping in the beef cattle (n=437). Pair-wise linkage analysis with four polymorphisms showed strong linkage disequilibrium (LD), and three major haplotypes (freq.>0.1) were constructed. Statistical analysis revealed that polymorphisms in intron1 (g.346G>A) and exon2 (g.592-597CTGCAG[Leu-Gln]insdel) showed significant association with marbling score (P(cor.)=0.003 and 0.02, respectively). One haplotype, ht2[C-G-G-del], also showed significant association with MS (P(cor.)=0.0004). Our findings suggest that polymorphisms in TCAP might be among the important genetic factors involved in carcass quality in beef cattle.

Outcome of bacteraemia in patients admitted to the adult medical wards of the UKM hospital.

The clinical outcome of bacteraemic patients is influenced by many factors. It is vital to know one's own local hospital epidemiological data so as to provide optimal care to the affected patients. This was a prospective, observational study carried out in the said patient population over a period of four months in the year 2005. One hundred and ninety one patients presented with bacteraemia over the study period. Fifty-two (27%) of the patients died. Mechanical ventilation, inappropriate empirical antibiotic usage, Chinese ethnicity and low serum albumin levels independently affected prognosis. These factors should alert physicians to those patients who require more intensive monitoring and care.

Risk factors for infection in Malaysian patients with systemic lupus erythematosus.

To determine the incidence, types and risk factors for infection in systemic lupus erythematosus (SLE) patients in Kuala Lumpur, Malaysia, we retrospectively reviewed the medical records of 102 patients with definite SLE attending a specialist clinic. Details of major infections (pneumonia or severe infection requiring intravenous therapy) and minor infections, and their time of onset in relation to immunosuppressive therapy and disease flares were recorded. There were 77 major and 163 minor infections during 564 patient-years of follow-up. In the month following a course of pulse methylprednisolone, the incidence of major infection was 20 times higher and the incidence of minor infection was 10 times higher than at other periods (p < 0.0001). In the month after disease flare, the incidence of major infection was 10 times higher and the incidence of minor infection six times higher than at other times (p < 0.0001). After allowing for methylprednisolone therapy and disease flares, there was no increase in the rate of infections during treatment with azathioprine, oral or intravenous cyclophosphamide. There was no effect of renal involvement on infection rate.

A study of Malaysian drug addicts with human immunodeficiency virus infection.

A cross-sectional study was undertaken to determine the clinical profile, haematological and biochemical changes, seroprevalence of common opportunistic pathogens, and AIDS-defining events in 49 Malaysian male drug addicts with HIV infection. Their mean age was 33.2 years, the majority had been injecting drugs for more than 5 years and 88% reporting sharing needles. Fatigue, weight loss and night sweats were common presenting symptoms and the most frequent physical findings were hepatomegaly (57%), lymphadenopathy (35%) and thrush (29%). Pulmonary infections were the commonest complications seen (61%) and of these, 13 had septic pulmonary emboli, 7 had bacterial pneumonias, 7 had pulmonary tuberculosis, and 4 had Pneumocystis carinii pneumonia. Eight patients had infective endocarditis and 5 had infected pseudoaneurysm in the groin. Anaemia (82%), leucocytosis (53%), hypoalbuminaemia (43%), hyperglobulinaemia (88%), elevated liver enzymes and hyponatraemia (57%) were frequent laboratory findings. The prevalence of HCV, HBV, cytomegalovirus and toxoplasma infection (by serology) were 100%, 12.2%, 72.7% and 59% respectively. All 7 patients with AIDS (4 P. carinii pneumonia, 2 extrapulmonary tuberculosis, and one oesophageal candidiasis) presented with their AIDS-defining illness, suggesting that HIV-infected intravenous drug user (IVDU) patients present late in the course of the disease.

PIP: A cross-sectional study of a cohort of 49 male human immunodeficiency virus (HIV)-infected intravenous drug users attending the Infectious Diseases Unit of the National University of Malaysia during 1991-94 yielded a clinical profile of these patients. The mean age of respondents was 33.2 years and the mean duration of intravenous drug use was 12.7 years. On average, these men had known of their HIV-positivity for 53.2 weeks. Intravenous drug use was the only reported HIV risk factor in 34 men (69%). Clinical symptoms at intake included fatigue (49%), weight loss (47%), night sweats (31%), fever (14%), and diarrhea (6%), while clinical findings included hepatomegaly (57%), lymphadenopathy (35%), and oral thrush (29%). Anemia (82%), leucocytosis (53%), hypoalbuminemia (43%), hyperglobulinemia (88%), elevated liver enzymes and hyponatremia (57%) were frequent laboratory findings. The prevalences of hepatitis B virus, cytomegalovirus, and toxoplasma infection were 12.1%, 72.7%, and 59%, respectively. A total of 91 diagnoses were made in these 49 patients: most common were pneumonia, tuberculosis, bacteremia, infective endocardiditis, mycotic aneurysm, and psychiatric disorders. The mean duration of known progression to acquired immunodeficiency syndrome (AIDS) in the 7 patients at this stage was 391 days. Pneumocystis carinii pneumonia was the most common AIDS-defining illness. Three months into the study, 19 men (57%) had defaulted, reflecting the difficulties of involving drug addicts in research and intervention projects. Moreover, 16 patients (33%) were first confirmed HIV-positive at presentation to the hospital, suggesting that many drug users' HIV status remains unknown until they develop symptoms requiring hospital care.

Cytomegalovirus retinitis and AIDS in Edinburgh.

The medical records, retinal drawings and fundus photographs of all patients with cytomegalovirus retinitis (CMVR) and AIDS in Edinburgh between 1986-1992 were reviewed to determine the efficacy of treatment in preserving vision. Ophthalmoscopic features of CMVR were observed in 32 eyes of 24 patients with AIDS, 19 males and 5 females. HIV transmission in this group was by homo/bisexual contact (16), injection drug use (7) and blood transfusion (1). Unilateral blurring was the commonest visual symptom although 9 (38%) patients had no visual symptoms. All patients presented with a corrected visual acuity of 6/12 or better in at least one eye. Following treatment with systemic ganciclovir or foscarnet 16 patients (66%) developed toxic side-effects of therapy and 13 (54%) experienced a recurrence of CMVR. Four (17%) patients developed a retinal detachment in one eye. The mean survival was 8.3 months after the diagnosis of CMVR. At final follow-up, between 2-26 months after the diagnosis of CMVR, 21 (87.5%) patients retained useful vision (6/18 or better) although 3 (12.5%) were effectively blind (less than 6/60). We conclude that with prompt diagnosis and treatment of CMVR vision can be preserved in the majority of cases.

Cytomegalovirus disease in AIDS: the Edinburgh experience.

Retrospective analysis of medical records of 557 HIV positive patients (including 113 with AIDS) revealed 17 patients with an antemortem clinical diagnosis of cytomegalovirus (CMV) disease. This group comprised 7 injection drug users (2 male and 5 female) and 10 homosexual men. Males were significantly older than females, and homosexual men were significantly older than drug users at the time of diagnosis of CMV. All 17 patients had evidence of retinitis, and 6 also had evidence of extraocular disease. CMV retinitis was the AIDS defining diagnosis in two patients, and the attack rate of CMV in all AIDS patients progressively increased with time, with a 3-year CMV-free survival of 57%. Fifteen patients with CMV disease had evidence of previous CMV infection (CMV IgG positive), with 7 also having a positive CMV IgM and 10 a positive viral culture. The mean CD4+ lymphocyte count at diagnosis of CMV was 17 cells/mm3, compared with 68 cells/mm3 at diagnosis of AIDS. Therapy was unsatisfactory, often being complicated by marrow suppression. Relapse occurred in 11 patients after initial improvement but despite this only 3 patients died with severe visual impairment. The mean survival after a diagnosis of CMV was 10.5 months. This study confirms that disease caused by CMV is usually a late manifestation of AIDS, and the increasing prevalence among patients with AIDS implies that, the longer the survival, the greater the risk of disease. Frequent fundoscopy in HIV positive patients is of paramount importance particularly in patients who have a CD4+ lymphocyte count of less than 100 cells/mm3.

Primary uterine lymphoma: a case report.

Primary lymphoma of the uterus is a rare disease, the reported characteristic MR imaging findings being homogeneous intermediate signal intensity of the indistinct mass on T1- and T2-weighted images, and the preservation of endometrial lining and uterine architecture. We report a case of primary uterine lymphoma which showed tumoral necrosis, endometrial disruption and diffuse anterior vaginal wall involvement.