Microstructured elastomeric surfaces with reversible adhesion and examples of their use in deterministic assembly by transfer printing

Reversible control of adhesion is an important feature of many desired, existing, and potential systems, including climbing robots, medical tapes, and stamps for transfer printing. We present experimental and theoretical studies of pressure modulated adhesion between flat, stiff objects and elastomeric surfaces with sharp features of surface relief in optimized geometries. Here, the strength of nonspecific adhesion can be switched by more than three orders of magnitude, from strong to weak, in a reversible fashion. Implementing these concepts in advanced stamps for transfer printing enables versatile modes for deterministic assembly of solid materials in micro/nanostructured forms. Demonstrations in printed two- and three-dimensional collections of silicon platelets and membranes illustrate some capabilities. An unusual type of transistor that incorporates a printed gate electrode, an air gap dielectric, and an aligned array of single walled carbon nanotubes provides a device example.     

Rates and impact of hepatitis on human immunodeficiency virus infection in a large African cohort

AIM:To determine the rates and impact of hepatitis B virus(HBV) and hepatitis C virus(HCV) infections on response to long-term highly active antiretroviral therapy(HAART) in a large human immunodeficiency virus(HIV) population in Nigeria.METHODS:HBV and HCV as well as HIV infections are endemic in sub Saharan Africa.This was a retrospective cohort study of 19 408 adults who were recruited between June 2004 and December 2010 in the AIDS Prevention Initiative in Nigeria in Nigeria programme at Jos University Teaching Hospital.Serological assays,including HBV surface antigen(HBsAg) and hepatitis C antibody were used to categorise hepatitis status of the patients.HBsAg was determined using enzyme immunoassay(EIA)(Monolisa HBsAg Ultra3;Bio-Rad).HCV antibody was tested using third generation EIA(DIA.PRO Diagnostic,Bioprobes srl,Milan,Italy).HIV RNA levels were measured using Roche COBAS Amplicor HIV-1 monitor test version 1.5(Roche Diagnostics,GmbH,Mannheim,Germany) with a detection limit of 400 copies/mL.Flow cytometry was used to determine CD4+ cell count(Partec,GmbH Munster,Germany).Comparison of categorical and continuous variables were achieved using Pearson’s χ 2 and Kruskal Wallis tests respectively,on MedCalc for Windows,version 9.5.0.0(MedCalc Software,Mariakerke,Belgium).RESULTS:With an overall hepatitis screening rate of over 90% for each virus;HBV,HCV and HBV/HCV were detected in 3162(17.8%),1983(11.3%) and 453(2.5%) HIV infected adults respectively.The rate of liver disease was low,but highest among HIV monoinfected patients(29,0.11%),followed by HBV coinfected patients(15,0.08%).Patients with HBV coinfection and triple infection had higher log 10 HIV RNA loads(HBV:4.6 copies/mL vs HIV only:4.5 copies/mL,P<0.0001) and more severe immune suppression(HBV:645,55.4%;HBV/HCV:97,56.7%) prior to initiation of HAART compared to HIV mono-infected patients(1852,48.6%)(P<0.0001).Of 3025 patients who were 4.4 years on HAART and whose CD4 cell counts results at baseline and end of follow up were available for     

Contributions of pulmonary hypertension to HIV-related cardiac dysfunction

Background/Aim

To evaluate the prevalence of pulmonary hypertension among patients living with HIV/AIDS and to determine its contribution to cardiac dysfunction.

Method

A hospital based cross sectional study was carried out over a 6-month period at the Jos University Teaching Hospital. The subjects were 200 confirmed HIV positive patients, ≥18 years of age who consented to the study. Physical examination, laboratory investigations, 2 dimensional and Doppler echocardiography were conducted on the subjects.

Results

The mean age of the patients was 38 ± 9 years, and there were 142 females (71%).Females were younger, mean age 36 ± 8 years versus 41 ± 10 years for males (p-value <0.01). The median CD4 cell count was 312 cells/μl, there were no homosexual or intravenous drug user among the subjects.Eight of the subjects had pulmonary hypertension, with a case prevalence of 4%, and this had no relationship to CD4 cell count. Both systolic and diastolic functions were worse in subjects with pulmonary hypertension, with a negative correlation between mean pulmonary arterial systolic pressure (mPASP) and parameters like ejection fraction (r = −0.28, p-value 0.0003), fractional shortening (r = −0.21, p-value 0.003), deceleration time (r = −0.13. p-value 0.09).

Conclusion

Immune-suppression affects the cardiac function adversely and coexisting pulmonary hypertension contributes to poor systolic and diastolic function in affected patients. The subtle nature of presentation of pulmonary hypertension and other cardiac dysfunctions in HIV/AIDS patients demand a high-index of suspicion and early intervention if detected, to ensure better care for these emerging threats to our patients.