A study of hospitalized COVID-19 patients with AKI in a setting of multiracial developing country.

BACKGROUND: The commonest indication for hospitalization in COVID-19 patients is hypoxemia or severe respiratory symptoms. However, COVID-19 disease may result in extrapulmonary complications including kidney-related pathology. The reported incidence of renal involvement related to COVID infection varies based on geographical location. OBJECTIVE: This study aimed to assess the incidence rate of AKI in hospitalized COVID-19 patients and identify risk factors and prognostic predictors. METHOD: In this retrospective study, we recruited hospitalized COVID-19 patients from January 2021 until June 2021 at the University Malaya Medical Center. The inclusion criteria were hospitalized for ≥ 48 h with confirmed COVID-19 infection and at least 18 years old. Patient demographic and clinical data were collected from electronic medical records. The staging of AKI was based on criteria as per KDIGO guidelines. RESULTS: One thousand five hundred twenty-nine COVID patients fulfilled the inclusion criteria with a male-to-female ratio of 759 (49.6%) to 770 (50.3%). The median age was 55 (IQR: 36-66). 500 patients (32.7%) had diabetes, 621 (40.6%) had hypertension, and 5.6% (n = 85) had pre-existing chronic kidney disease (CKD). The incidence rate of AKI was 21.1% (n = 323). The percentage of COVID patients in different AKI stages of 1,2 and 3 were 16.3%, 2.1%, and 2.7%, respectively. Fifteen hospitalized patients (0.98%) required renal replacement therapy. 58.8% (n = 190) of AKI group had complete recovery of kidney function. Demographic factors included age (p < 0.001), diabetes (p < 0.001), hypertension (p < 0.012), CKD (p < 0.001), and vaccination status (p = 0.042) were associated with an increased risk of developing AKI. We found that the AKI cohort had statistically significant lower platelet counts and higher ferritin levels than the non-AKI cohort. AKI is a risk predictor of prolonged hospitalization (p < 0.001) and higher mortality rates (P < 0.001). CONCLUSION: AKI is a common clinical complication among hospitalized COVID-19 patients. The etiology of AKI is multifactorial and may have an adverse impact on patient morbidity and mortality.

A study protocol for a double-blind randomised placebo-controlled trial evaluating the efficacy of carrageenan nasal and throat spray for COVID-19 prophylaxis-ICE-COVID.

INTRODUCTION: At present, vaccines form the only mode of prophylaxis against COVID-19. The time needed to achieve mass global vaccination and the emergence of new variants warrants continued research into other COVID-19 prevention strategies. The severity of COVID-19 infection is thought to be associated with the initial viral load, and for infection to occur, viruses including SARS-CoV-2 must first penetrate the respiratory mucus and attach to the host cell surface receptors. Carrageenan, a sulphated polysaccharide extracted from red edible seaweed, has shown efficacy against a wide range of viruses in clinical trials through the prevention of viral entry into respiratory host cells. Carrageenan has also demonstrated in vitro activity against SARS-CoV-2. METHODS AND ANALYSIS: A single-centre, randomised, double-blinded, placebo-controlled phase III trial was designed. Participants randomised in a 1:1 allocation to either the treatment arm, verum Coldamaris plus (1.2 mg iota-carrageenan (Carragelose®), 0.4 mg kappa-carrageenan, 0.5% sodium chloride and purified water), or placebo arm, Coldamaris sine (0.5% sodium chloride) spray applied daily to their nose and throat for 8 weeks, while completing a daily symptom tracker questionnaire for a total of 10 weeks. PRIMARY OUTCOME: Acquisition of COVID-19 infection as confirmed by a positive PCR swab taken at symptom onset or seroconversion during the study. Secondary outcomes include symptom type, severity and duration, subsequent familial/household COVID-19 infection and infection with non-COVID-19 upper respiratory tract infections. A within-trial economic evaluation will be undertaken, with effects expressed as quality-adjusted life years. DISCUSSION: This is a single-centre, phase III, double-blind, randomised placebo-controlled clinical trial to assess whether carrageenan nasal and throat spray reduces the risk of development and severity of COVID-19. If proven effective, the self-administered prophylactic spray would have wider utility for key workers and the general population. TRIAL REGISTRATION: NCT04590365; ClinicalTrials.gov NCT04590365. Registered on 19 October 2020.

Association of Pain and Impact of Dual-Task Exercise on Function, Cognition and Quality of Life.

PURPOSE: This study aimed to assess the factors associated with pain and evaluate the impact of dual-task exercise on pain improvement, quality of life (QOL), cognition and function in older adults. PATIENTS AND METHODS: This study is a secondary data analysis of the HAPPY (Healthy Ageing Promotion Program for You) study. At risk older adults ≥ 60 years old were enrolled in a community dual-task exercise program. Assessments for frailty, sarcopenia, falls, quality of life (QOL) and perceived health, depression, cognition and physical function were performed at baseline and 3 months. Pain intensity was derived from EQ-5D and stratified into no pain, slight pain and moderate to extreme pain. RESULTS: Out of 296 participants, 37.2% had slight pain and 11.1% had moderate to severe pain. Both slight and moderate to extreme pain compared with no pain group were significantly associated with lower perceived health (68.2,63.6 vs 76.0) and QOL index (0.70,0.59 vs 0.93); moderate to extreme pain was also significantly associated with depression, low mental vitality, frailty, sarcopenia and poorer physical performance. After 3 months of dual-task exercise, pain improved in 70.8% of the moderate to extreme pain group and 50.8% of slight pain group. Significant improvement in perceived health, QOL, physical function and cognition were also observed. CONCLUSION: Proactive efforts are required to screen for pain and manage frailty, sarcopenia and depression. Dual-task exercise proved safe and possibly effective in reducing pain and improving QOL, physical and cognitive function in older adults. Prospective randomized studies are needed to validate the effectiveness of dual-task vs single-task exercise, including impact of reversal of frailty and sarcopenia in pain management.

Frailty and Quality of Life in Older Adults with Metabolic Syndrome - Findings from the Healthy Older People Everyday (HOPE) Study.

OBJECTIVES: Metabolic syndrome (MetS) and frailty are both associated with increased morbidity and mortality. Frailty is associated with reduced quality of life (QoL) but association of QoL with MetS have produced mixed results suggesting that other factors such as disease burden, obesity and depression may have a more significant influence. We aim to investigate the demographics of frail participants with MetS, and relationship between frailty and QoL in MetS. METHODS: Cross-sectional population study involving 292 older adults ≥ 65 years with MetS. MetS was defined using the Modified ATP III for Asians which requires the presence of 3 or more of the following 5 components 1) waist circumference ≥ 90cm for males or ≥ 80cm for females, 2) TG ≥ 150mg/dL, 3) HDLc < 40mg/dL in males or < 50mg/dL in females, 4) blood pressure ≥ 130/85mmHg or use of anti-hypertensive medication, and 5) fasting plasma glucose ≥ 100mg/dL or use of pharmacological treatment for diabetes mellitus. Data were collected on demographics, frailty (FRAIL), QoL (Euroqol-5D), perceived health, functional status, cognition, Timed-Up-and-Go (TUG), and hand-grip strength (HGS). RESULTS: 40.4% of the participants were pre-frail (MetSprefrail) and 7.2% were frail (MetSfrail). MetSfrail were significantly older, had lower education level, higher polypharmacy burden and higher prevalence of diabetes. The prevalence of at least 1 activity of daily living impairment was 4 times higher, and depression 9 times higher than their robust counterparts. MetSfrail also had longer TUG, higher prevalence of poor grip strength and poor perceived health. After adjusting for age, gender and education, MetSfrail was significantly associated with much higher odds of EQ-5D moderate to extreme problems with mobility (Odds Ratio (OR) =10.99, CI 2.62-46.14), usual activities (OR=37.82, CI 3.77-379.04) and pain (OR=10.79, CI 3.18-36.62). EQ-5D Index Value and Perceived Health improved by 0.1 (Mean Difference (MD) =0.07, CI 0.04-0.10) and 6.0 (MD=6.01, CI 3.29-8.73) respectively as frailty status improved. CONCLUSION: Frailty in MetS is associated with depression, polypharmacy, greater functional impairment, poorer QoL and perceived health. Frailty screening and personalized management is crucial in MetS as frailty may be a mediator for negative outcomes in MetS, and frailty may be reversible.

Retroductal Delivery of Epidermal Growth Factor Protects Salivary Progenitors after Irradiation.

Salivary gland hypofunction after irradiation is associated with a deficit of epithelial stem/progenitors in salivary glands. Although epidermal growth factor (EGF) is known to stimulate the proliferation of epithelial cells, the therapeutic effect of EGF on salivary epithelial stem/progenitors remains undetermined. In this study, we administered EGF to submandibular glands (SMGs) via a retrograde route through the SMG excretory duct before fractionated irradiation and examined whether EGF could protect salivary epithelial progenitor cells from radiation and alleviate radiation-induced salivary hypofunction. EGF-treated mice exhibited greater body and gland weights at 12 wk after irradiation than untreated mice. The retroductal delivery of EGF improved salivary secretory function and increased salivary amylase activity in a dose-dependent manner. Histological examinations highlighted the amelioration of the loss of keratine-14+ (KRT14+) basal ductal and/or MIST1+ acinar cells, as well as induction of fibrosis, following irradiation in EGF-treated mice. An additional in vitro experiment using a salivary gland organoid irradiation model indicated that the radioprotective effects of EGF promoted the growth and inhibited the apoptotic cell death of salivary epithelial cells. Our results suggest that retroductal delivery of EGF may be a promising therapeutic option for preventing radiation-induced salivary gland hypofunction.

A longitudinal histologic evaluation of vitamin D receptor expression in the skeletal muscles of patients with a distal radius fracture.

We investigated the effect of vitamin D supplementation on the expression of muscle vitamin D receptor (VDR) and cross-sectional area (CSA) in patients with a distal radius fracture (DRF). Significant increases in VDR expression and CSA were observed, especially in vitamin D-deficient patients. PURPOSE: Vitamin D supplementation is known to enhance muscle mass and function, but whether the VDR is essential in this process remains unknown. We evaluated the change in VDR expression and CSA in the forearm muscles following vitamin D supplementation in patients with a DRF. METHODS: We prospectively recruited 18 women with a median age of 63.5 years who have a DRF. We obtained two biopsies of the forearm muscle, first at the time of fracture repair and then during hardware removal. We supplemented 1000 IU of vitamin D per day during a median interval of 8 months. We examined the changes in VDR expression and CSA by immunohistochemistry. RESULTS: The median serum 25-hydroxyvitamin D [25(OH)D] increased from 14.3 to 32.1 ng/mL (P = 0.001). The median VDR expression increased from 0.72 to 0.78 (P = 0.002), and the median CSA increased from 1290.0 to 1685.8 µm2 (P = 0.022). Significant increases in VDR expression and CSA were observed in vitamin D-deficient patients [25(OH)D] < 20 ng/mL, but not in vitamin D-non-deficient patients. The changes in VDR expression and CSA were in the same direction in 13 patients, but in the opposite direction in 5 patients. CONCLUSION: Vitamin D supplementation may increase muscle VDR expression and CSA in patients with a DRF, especially in vitamin D-deficient patients. The increase in CSA without an increase in VDR expression in some patients indicates that the effect of vitamin D supplementation on muscle mass could be mediated by indirect effect of serum vitamin D restoration and by VDR.

Slow Gait, Subjective Cognitive Decline and Motoric Cognitive RISK Syndrome: Prevalence and Associated Factors in Community Dwelling Older Adults.

BACKGROUND: Motoric Cognitive Risk Syndrome (MCR), slow gait speed (SG) and subjective cognitive decline (SCD) are known to be harbingers of dementia. MCR is known to be associated with a 3-fold increased risk of future dementia, while SG can precede cognitive impairment. OBJECTIVE: We aim to determine the prevalence and demographics of MCR, slow gait alone (SG-A) and subjective cognitive decline alone (SCD-A) in community-dwelling older adults and association with physical, functional, cognition and psychosocial factors. METHODS: A total of 509 participants were classified into four groups according to presence of SG and/or SCD. Multinomial logistic regression was used to identify the factors associated with SG-A, SCD-A and MCR. RESULTS: The prevalence of MCR was 13.6%, SG-A 13.0% and SCD-A 35.0%. Prevalence of MCR doubled every decade in females with 27.7% of female ≥ 80 years old had MCR. Almost 4 in 10 had no SG or SCD (SG+SCD negative). MCR and SG-A groups were significantly older, had higher body mass index (BMI), lower education, lower global cognition scores especially in non-memory domains, higher prevalence of low grip strength and lower short physical performance battery scores than those with SCD-A and SG+SCD negative. In addition, the SG-A group had significantly higher prevalence of multi-morbidity and diabetes. The prevalence of pain, depression, frailty, social isolation and activity of daily living impairment were significantly higher in MCR. The global cognitive and functional scores for those with SCD-A were comparable to the SG+SCD negative group. The Malay ethnic group had the lowest prevalence of SCD but highest prevalence of SG. After adjusting for confounding factors, age, BMI, frailty status, instrumental activity of daily living, depression and pain remained significantly associated with MCR. For SG-A, age, BMI, education and number of chronic diseases remained significant. CONCLUSION: Both MCR and SG-A are associated with global cognitive decline especially in the non-memory domains and lower functional scores. Gait speed is a good predictor of negative outcomes and should be considered as the 'sixth' vital sign. Long term prospective studies are needed to evaluate: i) the conversion to dementia in different ethnic groups and ii) effect of targeted physical and / or dual task exercise on delaying the conversion to dementia and / or improvement in physical measures and reduction of disability.

Using lactic acid bacteria and packaging with grapefruit seed extract for controlling Listeria monocytogenes growth in fresh soft cheese.

Various cheese products are involved in outbreaks of listeriosis worldwide due to high consumption and prolonged refrigerated storage. The objective of this study was to determine the efficacy of using lactic acid bacteria and packaging with grapefruit seed extract (GSE) for controlling Listeria monocytogenes growth in soft cheese. Leuconostoc mesenteroides and Lactobacillus curvatus isolated from kimchi were used as a starter culture to make a soft cheese, which was inoculated with a cocktail strain of L. monocytogenes. The soft cheese was packed with low-density polyethylene, biodegradable polybutylene adipate-co-terephthalate (PBAT), low-density polyethylene with GSE, or PBAT with GSE and stored at 10°C and 15°C. Leuconostoc mesenteroides (LcM) better inhibited the growth of L. monocytogenes than Lb. curvatus. The PBAT with GSE film showed the best control for the growth of L. monocytogenes. When both LcM and PBAT with GSE were applied to the soft cheese, the growth of L. monocytogenes was inhibited significantly more than the use of LcM or PBAT with GSE alone. In all test groups, water activity, pH, and moisture on a fat-free basis decreased, and titratable acidity increased compared with the control group. These results suggest that LcM isolated from kimchi and PBAT with GSE packaging film can be used as a hurdle technology to lower the risk of L. monocytogenes in soft cheese at the retail market.

Intrinsically p-type cuprous iodide semiconductor for hybrid light-emitting diodes.

Cuprous halides, characterized by a direct wide band-gap and a good lattice matching with Si, is an intrinsic p-type I-VII compound semiconductor. It shows remarkable optoelectronic properties, including a large exciton binding energy at room temperature and a very small piezoelectric coefficient. The major obstacle to its application is the difficulty in growing a single-crystal epitaxial film of cuprous halides. We first demonstrate the single crystal epitaxy of high quality cuprous iodide (CuI) film grown on Si and sapphire substrates by molecular beam epitaxy. Enhanced photoluminescence on the order of magnitude larger than that of GaN and continuous-wave optically pumped lasing were found in MBE grown CuI film. The intrinsic p-type characteristics of CuI were confirmed using an n-AlGaN/p-CuI junction that emits blue light. The discovery will provide an alternative way towards highly efficient optoelectronic devices compatible with both Si and III-nitride technologies.

Prognostic significance of lymphovascular invasion in patients with salivary duct cell carcinoma of the head and neck.

The purpose of this study was to evaluate the treatment outcomes of patients who underwent surgery with curative intention after the diagnosis of salivary duct cell carcinoma (SDC) in the head and neck area and to analyse the prognostic factors and treatment failure pattern. Fifty-nine patients treated between March 2003 and December 2018 were enrolled in the study. The mean follow-up period was 45.5 months (range 12-189 months). The 5-year overall survival rate was 54.7% and the 5-year disease-free survival rate was 56.8%. Nineteen recurrences occurred during the study period: four loco-regional recurrences and 15 distant metastases. During the study period, 10 patients died of disease relapse and 5 patients died of other medical caused. On univariate analysis, lymphovascular invasion (LVI) (P=0.031) showed the most significant correlation with mortality. On multivariate Cox regression analysis, LVI showed the most significant correlation with patient survival (P = 0.027). LVI was the most significant prognostic factor related to the 5-year overall survival rate of SDC patients. The development of novel therapeutic agents is necessary to improve the survival rate of these patients with LVI.

Functional Outcomes of Fragility Fracture Integrated Rehabilitation Management in Sarcopenic Patients after Hip Fracture Surgery and Predictors of Independent Ambulation.

OBJECTIVES: To compare the changes in the functional level of patients with versus without sarcopenia who received by fragility fracture integrated rehabilitation management (FIRM) after hip fracture (HF) surgery over a 6-month follow-up period and to identify variables influencing independent ambulation (IA) at 6 months after HF. DESIGN: Prospective observational study. SETTING: Three in-hospital rehabilitation setting. PARTICIPANTS: Patients older than 65 years of age (N=80) categorized by the presence of sarcopenia. INTERVENTION: The FIRM program during the-2 week hospital stay after surgery. MEASUREMENTS: Main outcomes for ambulatory function (Koval score, Functional Ambulatory Category) and other secondary outcomes were measured at rehabilitation admission, at discharge, at 3 months and 6 months after surgery. Other secondary outcomes were measured. The possibility of IA at 6 months after surgery were also investigated. RESULTS: Sarcopenia and non-sarcopenia patients did not differ significantly in terms of changes in ambulation or other functions over a 6-month follow-up (p < 0.001 or p = 0.001). The two groups did not differ significantly in terms of final functional status (6 months). The IA ratios of the two groups did not significantly differ at 6 months after surgery (sarcopenia [54.3%] and non-sarcopenia [64.5%]). IA before fracture (p = 0.039) and age (≥80 years) (p = 0.03) were independent predictors and sarcopenia was not a predictor for the possibility of IA at 6-months after surgery. CONCLUSIONS: The FIRM program was effective for promoting functional recovery in older patients with fragility HF, either with or without sarcopenia. The present findings provide evidence of the pressing need for integrated rehabilitation management in fragility fracture care to improve functional recovery in patients with sarcopenia.

Interventional treatment of bleeding complications due to percutaneous cannulation for peripheral extracorporeal membrane oxygenation.

PURPOSE: This study aimed to evaluate the safety and effectiveness of interventional techniques as a treatment for bleeding complications secondary to percutaneous cannulation for peripheral extracorporeal membrane oxygenation (PECMO). MATERIALS AND METHODS: Out of 1264 patients who underwent PECMO at our hospital between January 2009 and September 2018, we reviewed the clinical characteristics and outcomes of eight patients (4 men, 4 women; mean age, 54.9 years [range, 31-77 years]) who underwent percutaneous interventional treatment for bleeding complications secondary to percutaneous cannulation for PECMO. RESULTS: Both hemodynamic instability and coagulopathy were present in 7 patients who had direct injury during PECMO insertion and absent in one patient with pseudoaneurysm at the PECMO removal site. Percutaneous ultrasound-guided thrombin injection was performed in three patients with pseudoaneurysm of the common or superficial femoral artery, and adjunctive embolization was combined with microcoils or n-butyl 2-cyanoacrylate in two of them. Stent graft was inserted in four patients with contrast extravasation (n=3) from external iliac artery (n=1) or common femoral or iliac veins (n=2) ruptures or the fistula between the superficial femoral artery and vein (n=1). N-butyl 2-cyanoacrylate and coil embolization was performed for pseudoaneurysm from the internal pudendal artery branch in the remaining one patient. Technical success was achieved in all eight patients. There were no procedure-related complications. There was no rebleeding during the follow-up. CONCLUSION: Interventional treatment is a safe, technically feasible and therapeutically effective modality for treating bleeding complications secondary to a percutaneous cannulation for PECMO.

Depth extraction with offset pixels.

Numerous depth extraction techniques have been proposed in the past. However, the utility of these techniques is limited as they typically require multiple imaging units, bulky platforms for computation, cannot achieve high speed and are computationally expensive. To counter the above challenges, a sensor with Offset Pixel Apertures (OPA) has been recently proposed. However, a working system for depth extraction with the OPA sensor has not been discussed. In this paper, we propose the first such system for depth extraction using the OPA sensor. We also propose a dedicated hardware implementation for the proposed system, named as the Depth Map Processor (DMP). The DMP can provide depth at 30 frames per second at 1920 × 1080 resolution with 31 disparity levels. Furthermore, the proposed DMP has low power consumption as for the aforementioned speed and resolution it only requires 290.76 mW. The proposed system makes it an ideal choice for depth extraction systems in constrained environments.

Depressive Symptoms, Falls, and Fear of Falling in Old Korean Adults: The Korean Longitudinal Study on Health and Aging (KLoSHA).

Fall is a common cause of disability and death in old adults, and much research has been focused on identifying risk factors and developing preventive measures. Yet the majority of preceding research has been focused on physical performance. This study aims to evaluate the association between fall and depressive symptoms in community-dwelling elderly. Cross-sectional data of 431 men and 546 women was collected from old Korean adults living in Seongnam, Korea. Geriatric fall assessment was conducted by self-report questionnaires. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression Scale. Results indicated that depressive symptoms were associated with both fall and fear of falling in old adults. A clear gender difference was newly discovered, as depression played a stronger role in women. These results imply that clinicians should consider the negative affect of geriatric patients when assessing fall risk. Also, measures against depression might be effective in reducing falls.

Organotypic Spheroid Culture to Mimic Radiation-Induced Salivary Hypofunction.

Radiation treatment often leads to irreversible damage to normal salivary glands (SGs) because of their proximity to head and neck cancers. Optimization of the in vitro model of irradiation (IR)-induced SG damage is warranted to investigate pathophysiology and monitor treatment outcome. Here, we present an organotypic spheroid culture model to investigate the impact of IR on SGs and the mechanisms underlying IR-induced structural and functional changes. Human parotid epithelial cells were obtained from human parotid glands and plated on either plastic plates or Matrigel. A number of 3-dimensional (3D) spheroids were assembled on Matrigel. After IR at 10 and 20 Gy, morphologic changes in cells in 2D monolayers and 3D spheroids were observed. As the structural integrity of the 3D spheroids was destroyed by IR, the expression levels of salivary epithelial and structural proteins and genes decreased proportionally with radiation dosage. Furthermore, the spheroid culture allowed better measurement of functional alterations following IR relative to the monolayer culture, in which IR-inflicted spheroids exhibited a loss of acinar-specific cellular functions that enable Ca2+ influx or secretion of α-amylase in response to cholinergic or ß-adrenergic agonists. p53-mediated apoptotic cell death was observed under both culture conditions, and its downstream signals increased, such as p53 upregulated modulator of apoptosis (PUMA), Bax, cytochrome c, caspase 9, and caspase 3. These results suggest that the organotypic spheroid culture could provide a useful alternative model for exploration of radiobiology and mode of action of new therapies for prevention of radiation-induced salivary hypofunction.

Screening Nuclear Field Fluctuations in Quantum Dots for Indistinguishable Photon Generation.

A semiconductor quantum dot can generate highly coherent and indistinguishable single photons. However, intrinsic semiconductor dephasing mechanisms can reduce the visibility of two-photon interference. For an electron in a quantum dot, a fundamental dephasing process is the hyperfine interaction with the nuclear spin bath. Here, we directly probe the consequence of the fluctuating nuclear spins on the elastic and inelastic scattered photon spectra from a resident electron in a single dot. We find the in-plane component of the nuclear Overhauser field leads to detuned Raman scattered photons, broadened over experimental time scales by field fluctuations, which are distinguishable from both the elastic and incoherent components of the resonance fluorescence. This significantly reduces two-photon interference visibility. However, we demonstrate successful screening of the nuclear spin noise, which enables the generation of coherent single photons that exhibit high visibility two-photon interference.

Cation exchange synthesis of uniform PbSe/PbS core/shell tetra-pods and their use as near-infrared photodetectors.

In this work we explore the preparation of complex-shaped semiconductor nanostructures composed of different materials via a cationic exchange process in which the cations of the original semiconductor nanostructure are replaced by cations of different metals with preservation of the shape and the anionic framework of the nanocrystals. Utilizing this cation exchange method, we synthesized two new tetrapods for the first time: Cu2-xSe/Cu2-xS and PbSe/PbS, both prepared from CdSe/CdS tetrapods as 'templates'. We also fabricated near-infrared (NIR) photodetectors with a very simple architecture comprising a PbSe/PbS tetrapod layer between two Au electrodes on a glass substrate. When illuminated by a NIR laser, these devices are capable of achieving a responsivity of 11.9 A W(-1) without the use of ligand-exchange processes, thermal annealing or hybrid device architecture. Transient absorption spectroscopy was carried out on these PbSe/PbS tetrapods, the results of which suggest that the branched morphology contributes in part to device performance. Investigation of the charge dynamics of the PbSe/PbS tetrapods revealed an extremely long-lived exciton recombination lifetime of ∼17 ms, which can result in enhanced photoconductive gain. Overall, these heterostructured tetrapods showcase simultaneously the importance of nanoparticle shape, band structure, and surface chemistry in the attainment of NIR photodetection.

Kinetic studies of CO2 methanation over a Ni/γ-Al2O3 catalyst.

The production of methane by reacting CO2 with H2 (CO2 methanation) has the potential for producing synthetic natural gas, which could be exported using the existing infrastructure for the distribution of natural gas. The methanation of CO2 was investigated over a wide range of partial pressures of products and reactants using (i) a gradientless, spinning-basket reactor operated in batch mode and (ii) a laboratory-scale packed bed reactor operated continuously. The rate and selectivity of CO2 methanation, using a 12 wt% Ni/γ-Al2O3 catalyst, were explored at temperatures 445-497 K and pressures up to 20 bar. Research with the batch reactor showed that the rate increased with increasing partial pressures of H2 and CO2 when the partial pressures of these reactants were low; however, the rate of reaction was found to be insensitive to changes in the partial pressures of H2 and CO2 when their partial pressures were high. A convenient method of determining the effect of H2O on the rate of reaction was also developed using the batch reactor and the inhibitory effect of H2O on CO2 methanation was quantified. The kinetic measurements were compared with a mathematical model of the reactor, in which different kinetic expressions were explored. The kinetics of the reaction were found to be consistent with a mechanism in which adsorbed CO2 dissociated to adsorbed CO and O on the surface of the catalyst with the rate-limiting step being the subsequent dissociation of adsorbed CO. The ability of the kinetic expressions to predict the results from the continuous, packed-bed reactor was explored, with some discrepancies discussed.

Muscle plasticity related to changes in tubulin and αB-crystallin levels induced by eccentric contraction in rat skeletal muscles.

We used the model of eccentric contraction of the hindlimb muscle by Ochi et al. to examine the role of eccentric contraction in muscle plasticity. This model aims to focus on stimulated skeletal muscle responses by measuring tissue weights and tracing the quantities of αB-crystallin and tubulin. The medial gastrocnemius muscle (GCM) responded to electrically induced eccentric contraction (EIEC) with significant increases in tissue weight (p < 0.01) and the ratio of tissue weight to body weight (p < 0.05); however, there was a decrease in soleus muscle weight after EIEC. EIEC in the GCM caused contractile-induced sustenance of the traced proteins, but the soleus muscle exhibited a remarkable decrease in α-tubulin and a 19% decrease in αB-crystallin. EIEC caused fast-to-slow myosin heavy chain (MHC) isoform type-oriented shift within both the GCM and soleus muscle. These results have shown that different MHC isoform type-expressing slow and fast muscles commonly undergo fast-to-slow type MHC isoform transformation. This suggests that different levels of EIEC affected each of the slow and fast muscles to induce different quantitative changes in the expression of αB-crystallin and α-tubulin.

MyD88 in donor bone marrow cells is critical for protection from acute intestinal graft-vs.-host disease.

To understand the role of myeloid differentiation factor 88 (MyD88) expressed by donor bone marrow (BM) in the pathophysiology of graft-vs.-host disease (GVHD), we investigated the effects of transplantation of MyD88-deficient T cell-depleted BM (MyD88KO TCD-BM) on the severity of GVHD. Transplantation with MyD88KO TCD-BM aggravated GVHD; serious gut damage was evident, with high infiltration of T cells into the intestines of recipients and markedly reduced expansion of CD11b(+)Gr-1(+) myeloid-derived suppressor cells (MDSCs). MDSCs from MyD88KO mice were defective in inducing donor T-cell apoptosis and inhibiting T-cell proliferation. Supplementation of transplanted mice with MDSCs from wild-type mice, but not MyD88KO mice, attenuated GVHD severity with reduced intestinal T-cell infiltration in MyD88KO TCD-BM recipients. Pretreatment of BM donors with lipopolysaccharide to increase MDSC levels and MyD88 transcription in the TCD-BM transplant alleviated GVHD severity and intestinal T-cell infiltration. The T cell/MDSC ratios were correlated with intestinal GVHD severity in both animal models and human patients. This study indicates that MyD88-dependent MDSC expansion from donor BM is critical for protection against fatal intestinal GVHD.