Electrically and Thermally Conducting Nanocomposites for Electronic Applications

Nanocomposites made up of polymer matrices and carbon nanotubes are a class of advanced materials with great application potential in electronics packaging. Nanocomposites with carbon nanotubes as fillers have been designed with the aim of exploiting the high thermal, electrical and mechanical properties characteristic of carbon nanotubes. Heat dissipation in electronic devices requires interface materials with high thermal conductivity. Here, current developments and challenges in the application of nanotubes as fillers in polymer matrices are explored. The blending together of nanotubes and polymers result in what are known as nanocomposites. Among the most pressing current issues related to nanocomposite fabrication are (i) dispersion of carbon nanotubes in the polymer host, (ii) carbon nanotube-polymer interaction and the nature of the interface, and (iii) alignment of carbon nanotubes in a polymer matrix. These issues are believed to be directly related to the electrical and thermal performance of nanocomposites. The recent progress in the fabrication of nanocomposites with carbon nanotubes as fillers and their potential application in electronics packaging as thermal interface materials is also reported.     

Impact of Kaposi sarcoma-associated herpesvirus (KSHV) burden and HIV coinfection on the detection of T cell responses to KSHV ORF73 and ORF65 proteins

Cellular immune responses to Kaposi sarcoma-associated herpesvirus (KSHV), the etiological agent of KS and several other malignancies, are incompletely characterized. We assessed KSHV-specific interferon- gamma enzyme-linked immunospot responses in a cohort of 154 individuals, using overlapping peptide sets spanning the KSHV-encoded latency-associated nuclear antigen (ORF73) and the minor capsid glycoprotein (ORF65). Among KSHV-seropositive subjects, ORF73-specific responses dominated over responses to ORF65 and were preferentially detected in human immunodeficiency virus-coinfected individuals who had elevated levels of cell-associated KSHV DNA, indicating that the viral antigen burden may have been driving these responses. Responses to both ORF73 and ORF65 were also detected in several KSHV-seronegative subjects who were at increased risk for KSHV infection, which demonstrates that cellular immunity can be found in the absence of detectable humoral responses. These data have implications for the reliable identification of KSHV infection and may help guide the design of immune-based therapeutic and prophylactic interventions.     

Recombinant CD4-Pseudomonas exotoxin hybrid protein displays HIV-specific cytotoxicity without affecting MHC class II-dependent functions

The present study describes several in vitro activities of CD4(178)-PE40, a recombinant protein containing a portion of human CD4 linked to active regions of Pseudomonas aeruginosa exotoxin A. Using assays for cell viability, we demonstrate that the hybrid toxin displays highly selective cytotoxicity for HIV-infected T lymphocytes. In a latently infected human T-cell line which is inducible for HIV expression, toxin sensitivity is observed only upon virus induction. At concentrations which readily kill HIV-infected T cells, CD4(178)-PE40 has no observable cytotoxic effects on uninfected human cell lines expressing surface major histocompatibility complex (MHC) Class II molecules, and does not interfere with cellular responses known to be dependent on functional association between CD4 and MHC Class II molecules.     

Provider Response to Critical Action Values for Hypoglycemia in the Ambulatory Setting: a Retrospective Cohort Study

BackgroundThe blood glucose level triggering a critical action value (CAV) for hypoglycemia is not standardized, and associated outcomes are unknown.ObjectiveTo evaluate the clinical consequences of, and provider responses to, CAVs for hypoglycemia.DesignRetrospective cohort study at Johns Hopkins Hospital and Johns Hopkins Bayview Medical Center between April 1, 2013, and January 31, 2017.ParticipantsPatients with an ambulatory serum glucose < 50 mg/dL. Point-of-care capillary glucose and whole blood glucose samples were excluded.Main MeasuresElectronic medical record (EMR) review for providers’ documented response to CAV, associated patient symptoms, and serious adverse events.Key ResultsWe analyzed 209 CAVs for hypoglycemia from 154 patients. The median age (IQR) was 59 years (46, 69), 89 (57.8%) were male, and 96 (62.3%) were black. Provider-to-patient contact occurred in 128 of 209 (61.2%) episodes, among which no documented etiology was observed for 81 of 128 (63.3%), no recommendations were provided in 32 of 128 (25.0%), and no patient-reported hypoglycemic symptoms were documented in 103 of 128 (80.5%). Serious adverse events were documented in 4 of 128 episodes (3.1%), two required glucagon administration, and three required an ED visit. Provider-to-patient contact was associated with the patient having malignant neoplasm (adjusted OR 3.63, p = 0.045) or a hypoglycemic disorder (adjusted OR 7.70, p = 0.018) and inversely associated with a longer time from specimen collection to EMR result (adjusted OR 0.90 per hour, p = 0.016).ConclusionsThere is inconsistent provider-to-patient contact following CAVs for hypoglycemia, and the etiology and symptoms of hypoglycemia were infrequently documented. There were few serious documented adverse events associated with hypoglycemia, although undocumented events may have occurred, and the incidence of serious adverse events in non-contacted patients remains unknown. These findings demonstrate a need to standardize provider response to CAVs for hypoglycemia. Decreasing the lag time between sample collection and laboratory result reporting may increase provider-to-patient contact.KEY WORDS: Hypoglycemia, Critical action value, Ambulatory, Glucose     

Endoscopic management of pancreatic pseudocysts and walled-off pancreatic necrosis: A two-decade experience

Aim

To determine long-term outcome of endoscopic management of pancreatic pseudocyst/walled-off pancreatic necrosis (WOPN) without necrosectomy.

Methods

One-hundred and sixty-five pancreatic pseudocysts/WOPN managed endoscopically over a period of 22 years were analyzed retrospectively for technical success, complications, and recurrence.

Results

Symptomatic 118 males and 47 females with mean age of 35.8 years were included. Alcohol was the most common etiology (41.2 %). Transmural endoscopic drainage was done in 144 patients, while 21 patients underwent transpapillary drainage. All the patients were subjected to contrast computed tomography (CT) abdomen or routine/Doppler ultrasound. Endoscopic ultrasound was done in last 11 patients. One or two double pigtail 7 Fr stents were placed when clear watery fluid came out from cyst (130 patients, 78.8 %), and nasocystic drainage (NCD) tubes were placed in addition to two 7 Fr stents when there were frank pus, thick dark fluid, or solid components inside the cyst (35 patients). All these patients settled on this treatment. Thirty-three of 35 patients of WOPN could be managed endoscopically without necrosectomy. Complications occurred in 9.2 % of pseudocysts and 40 % of WOPN. Thirty-five patients were followed up for more than 5 years (3 patients more than 10 years), and 130 patients were followed up for up to 5 years. Recurrence occurred in 8.1 % of pseudocysts and 5.7 % of WOPN.

Conclusion

Majority of pancreatic pseudocysts/WOPN can be managed with endoscopic drainage without necrosectomy with high success, low complication, and recurrence rates.

     

Magnetic resonance imaging for evaluating neurogenic dysphagia

Dysphagia due to CNS pathology usually stems from one of two patterns of disease: (1) bilateral corticobulbar tract dysfunction (“pseudobulbar palsy”) or (2) pontomedullary dysfunction (“bulbar palsy”). Computed tomography (CT) has proved to be useful for evaluating the brainstem in patients with neurogenic dysphagia. Nonetheless, artifacts are common in CT imaging of the posterior fossa. Also, direct sagittal imaging is not usually obtainable by CT in adult patients. Magnetic resonance imaging (MRI), in contrast to CT, simultaneously gathers sequential images in the same plane and can obtain direct reconstructions in any plane of interest. MRI has proven to be more sensitive than CT in demonstrating lesions of the brain, such as demyelinating (e.g., multiple sclerosis) and ischemic diseases, (Brant-Zawadzki et al. 1984, Bradley et al. 1984, Bydder et al. 1982, Sheldon et al. 1985) as well as neoplastic masses that may produce neurogenic dysphagia (Lee et al. 1985, Zimmerman et al. 1986). Five patients with dysphagia are reported for whom MRI was valuable in detecting and characterizing their lesions of the brainstem and the cerebral hemispheres.     

Retained surgical sponge after laparotomy

Erosion of a retained surgical sponge into the intestine is an unusual occurrence and may make its appearance months or years later. The demonstration of a distended bowel by the barium-impregnated mass with multiple polypoidal filling defects in a patient who has undergone previous laparotomy should lead the physician to suspect a retained surgical sponge. Surgical intervention is rewarding.