Quality control in the decentralized production of biosand filters: a pilot workshop in Zambia

The locally produced, concrete biosand filter is a household water treatment option for improving water quality. As of December 2015, over 830,000 biosand filters had been implemented in 60 countries around the world. Local, decentralized production is an advantage of the technology but also creates challenges with quality control. This paper describes the development, piloting and evaluation of a quality control workshop in Zambia. The overall reaction to the workshop was positive. Based on results from the pilot, CAWST will revise the workshop to better achieve learning outcomes and improve the efficacy of the workshop

Quality control in the decentralized production of biosand filters: a pilot workshop in Zambia

The locally produced, concrete biosand filter is a household water treatment option for improving water quality. As of December 2015, over 830,000 biosand filters had been implemented in 60 countries around the world. Local, decentralized production is an advantage of the technology but also creates challenges with quality control. This paper describes the development, piloting and evaluation of a quality control workshop in Zambia. The overall reaction to the workshop was positive. Based on results from the pilot, CAWST will revise the workshop to better achieve learning outcomes and improve the efficacy of the workshop

Visual Sensor for Sterilization of Polymer Fixtures Using Embedded Mesoporous Silicon Photonic Crystals

A porous photonic crystal is integrated with a plastic medical fixture (IV connector hub) to provide a visual colorimetric sensor to indicate the presence or absence of alcohol used to sterilize the fixture. The photonic crystal is prepared in porous silicon (pSi) by electrochemical anodization of single crystal silicon, and the porosity and the stop band of the material is engineered such that the integrated device visibly changes color (green to red or blue to green) when infiltrated with alcohol. Two types of self-reporting devices are prepared and their performance compared: the first type involves heat-assisted fusion of a freestanding pSi photonic crystal to the connector end of a preformed polycarbonate hub, forming a composite where the unfilled portion of the pSi film acts as the sensor; the second involves generation of an all-polymer replica of the pSi photonic crystal by complete thermal infiltration of the pSi film and subsequent chemical dissolution of the pSi portion. Both types of sensors visibly change color when wetted with alcohol, and the color reverts to the original upon evaporation of the liquid. The sensor performance is verified using E. coli-infected samples

Cloning strategy used to build the scFv phage display libraries with synthetic structurally shaped V_H-CDR3 containing the α- and 3₁₀-helix.

<p>A. pHEN1 plasmid backbone containing scFv was used as the PCR template gene to be amplified with the primers LMB3 and the Primer 1 or 2 that includes the FR3 sequences (yellow), flanked by the α- or 3₁₀-helix algorithms (red) and followed by JH4 sequences (brown). B. After PCR amplification the resulted V_H gene segment was rearranged with α- or 3₁₀-helix V_H-CDR3 (red). To incorporate a unique Xho1 restriction site, the PCR products derived from step A were amplified with LMB3 and Primer 3. C. The resultant PCR products from step B were digested with Nco1 and Xho1 for insertion into the pIT2 plasmid backbone that contain light chain repertoire.</p

Oligonucleotides used to build the structural guided library.

<p>Oligonucleotides used to build the structural guided library.</p

NMR solution Structure of D25p and D34p.

<p>Figure shows the 3D-rendering model for each peptide based on the mean of 20 NMR structures. Both peptides exhibited the RGD-helix motif. D34 which has 22 amino-acids has a shorter helix than peptide D25, which has 29 amino-acids. Helices for both peptides were defined as standard α-helix with the D34 α-helix running from Leu6-Leu17 and D25 α-helix running from Leu6-Gln25.</p

Screening of phage clones isolated from the α-helix & 3₁₀-helix libraries.

<p>A) Monoclonal scFv screening ELISA testing 96 clones in each library. Bacterial supernatants were added to 5 µg/ml recombinant αvβ6 immobilized onto ELISA plate and then probed with mouse anti-Myc antibody followed by anti-mouse-HRP. B) Clones with unique sequences were screened for binding cellular αvβ6 by flow cytometry. Figure shows examples where scFv was tested at 100 (red histogram), 10 (orange histogram) and 1 (green histogram) µg/ml. For clarity the relevant αvβ6-specific mouse monoclonal antibody 10D5 (grey) and the negative control IgG (black) histograms are also shown in each plot. C) Binding to cellular αvβ6 by D25 and D34 verified by flow cytometry at 100 (red histogram), 10 (orange histogram) and 1 (green histogram) µg/ml. Size-exclusion chromatography profile of purified of D25scFv and D34scFv showed a major peaks at 30 kDa.</p

Internalisation of D25scFv, D34scFv, D25p and D34p in αvβ6-expressing cells.

<p>Internalisation of bound D25scFv (A,B) and D34scFv (D, E) was assessed at 0 mins (A,D) and 45 mins (B,C,E,F) in αvβ6-expressing cells (A,B,D,E) and detected using anti-myc antibody. In control cells (C,F) only anti-myc antibody was used. The scFvs both were internalised by αvβ6-expressing cells and some located to the nucleus. The absence of nuclear staining with anti-myc antibody alone suggests this was a true nuclear localisation. Internalisation of D25p (G, H, I) and D34p (J, K, L) was assessed in αvβ6-expressing cells ((G,H,J,K) and αvβ6-negative cells (I, L) at the times indicated. Both peptides were internalised only by αvβ6-expressing cells. The scale bar shown represents 20 µm.</p

Localization of radiolabelled D25p <i>in vivo</i>.

<p>Single Photon Emission Computed Tomography imaging was used to localize the Indium-111 radiolabelled D25p <i>in vivo</i>. The figure in the left panel represents a representative mouse at the one-hour time point, post injection. The three images represent three different viewing angles – the sagittal (left), coronal (middle) and axial (right). Significantly more radioactivity was retained by the αvβ6 positive tumour (indicated with solid arrow) compared with the αvβ6 negative tumour (indicated with the dashed arrow). Quantitative data showing the average retention of radioactivity per gram of tumour in the three tested mice at the 1 h, 4 h and 24 h time points are shown in the histogram. Significantly more radioactivity was retained by the αvβ6 positive tumour (p<0.01) compared with the αvβ6 negative tumour, and significantly higher at 1 hr compare to 4 and 24 hr (p<0.01). No significant difference were seen in radioactivity retention in the αvβ6 negative tumour between 1 hr and 4 and 24 hr in the (p>0.05).</p

α-helix and 3₁₀-helix Library design.

<p>A) Amino acid sequence and NMR solution structure of A20FMDV2 with a hairpin structure with RGD at the tip of the turn followed by a C-terminal helix is shown. B) α-helix algorithm used to design the V_H-CDR3 encoding a hairpin containing at its turn an RGD motif, followed by a C-terminal α-helix. C) 3₁₀-helix algorithm used to designed the V_H-CDR3 encoding a hairpin containing at its turn an RGD motif, followed by a C-terminal 3₁₀-helix. Amino acid positions that are available for randomisation are highlighted (X and Z shown in blue and red, respectively).</p