Optimum design of drip irrigation system using microtubes as emitters

Drip irrigation is a system in which water is supplied directly to plant roots with a pressure and flow rate to meet the crop water requirement. Clogging and emission non-uniformity, for a long time, have been the major obstacles in the development of drip irrigation. It would be a serious problem in areas with brackish water where the problems of precipitation of calcium carbonate, organic materials and suspended sands are severe. In order to obtain the best emission uniformity (EU) in uneven lands the pressure regulators and pressure compensating emitters (a gadget) have been used. However, pressure compensating emitters tend to be more complex and costly than non-compensating emitters and are not easy to apply. In this study, the possibility of utilizing small diameter pipes approximately 2 to 4 mm called microtubes have been discussed for enhancing the discharge uniformity of the drip irrigation and decreasing the difficulties encountered by those emitters due to clogging and blockage. Microtubes have many advantages compared to other types of emitters in terms of cost and practical applications. As these small size pipes are made of flexible materials can be adjusted in shape and length without difficulty. By adjusting the microtube lengths at different points along the lateral according to energy head developed, an equal outflow can be delivered to evenly spaced plants in the field. Here microtubes act as emitters. The variation of the microtube lengths are done for dissipating the extra heads above a threshold value. This threshold energy head value has been set, at the very last microtube of the end-lateral in a given manifold (or subunit), equal to the frictional and other minor energy heads lost for that minimum length microtube required to reach the plant under consideration. The results of study show that larger sizes microtubes have higher variation of length, while applying larger flow rates can decrease the length variation along the lateral. Few examples are prepared to demonstrate the drip irrigation design parameters in typical subunit sizes

Consent and parental responsibility - the past, the present and the future

Introduction: Informed consent is the 'permission or agreement' given by the patient for a proposed action. This paper explores the clinician's role in obtaining informed consent, provides an overview of consent and parental responsibility in the UK, and presents practical adjuncts to aid dental professionals in ascertaining who has parental responsibility to delineate persons capable of providing assent on behalf of an underage patient. / Consent and parental responsibility: While the principles of consent have largely stayed constant with time, subtleties in parental responsibility legislation exist in different regions of the UK. An audit exploring consent and parental responsibility knowledge among clinicians within the orthodontic department at the UCLH Eastman Dental Hospital demonstrated that none of the respondents met the gold standard (100%). The results ranged from 59-89% with a mean score of 74%. The majority of questions answered incorrectly related to knowledge of parental responsibility. / Conclusion: It is the responsibility of clinicians providing any care within the UK to stay up to date with legislation and regulations regarding consent and parental responsibility. Knowledge-based questionnaires can highlight areas of knowledge deficit which can be addressed through continuous professional development. This paper provides a flowchart summarising parental responsibility and a prefilled parental responsibility questionnaire as adjuncts to simplify the process of dental professionals ascertaining parental responsibility

Mechanical and surface chemical analysis of retrieved breast implants from a single centre

INTRODUCTION: Breast implants are associated with complications such as capsular contracture, implant rupture and leakage often necessitating further corrective surgery. Re-operation rates have been reported to occur in up to 15.4% of primary augmentation patients and up to 27% in primary reconstructions patients within the first three years (Cunningham, 2007). The aim of this study was to examine the mechanical and surface chemical properties as well as the fibroblast response of retrieved breast implants in our unit to determine the in vivo changes which occur over time. METHODS: Ethical approval was obtained. 47 implants were retrieved. Implantation time ranged from 1 month to 388 months (Mean 106.1 months). Tensile strength, elongation, Young's modulus and tear strength properties were measured using Instron 5565 tensiometer on anterior and posterior aspects of the implant. Attenuated total reflectance-fourier transform infra-red spectroscopy (ATR-FTIR), wettability and scanning electron microscopy (SEM) analysis was performed on the shell surfaces. Bicinchoninic acid assay was performed to determine shell protein content. The fibroblast response was determined by seeding HDFa cells on the retrieved implants and cell metabolism measured using Alamar Blue™ assay. RESULTS: Mechanical properties fall with increasing duration of implantation. There were no significant changes in ATR-FTIR spectra between ruptured and intact implants nor significant changes in wettability in implants grouped into 5 year categories. SEM imaging reveals surface degradation changes with increasing duration of implantation. CONCLUSIONS: With increasing duration of implantation, mechanical properties of the breast implants fall. However this was not associated with surface chemical changes as determined by ATR-FTIR and wettability nor protein content of the shells. Thus the reduction in mechanical properties is associated with breast implant failure but further research is required to elucidate the mechanisms

Patient, clinician and independent observer perspectives of shared decision making in adult orthodontics.

OBJECTIVES: To investigate and compare the extent of shared decision making (SDM) in orthodontics from the perspective of patients, clinicians and independent observers. DESIGN: A cross-sectional, observational study. SETTING: NHS teaching hospital. PARTICIPANTS: A total of 31 adult patients and their treating clinicians were included in the study. METHODS: The extent of SDM in new patient orthodontic consultations was measured using three versions of a validated instrument: the self-administered patient dyadic-OPTION scale; the self-administered clinician dyadic-OPTION scale; and an independent observer-rated OPTION12 scale. Patients and clinicians completed the 12-item dyadic-OPTION questionnaire independently at the end of the consultation to rate their perceived levels of SDM. The consultations were also audio-recorded and two calibrated raters independently rated the extent of SDM in these consultations using the OPTION12 scale. RESULTS: There was excellent inter-rater reliability between the two independent raters using the OPTION12 scale (intraclass correlation coefficient (ICC) = 0.909). The mean patient, clinician and independent observer OPTION scores for SDM were 90.4% (SD 9.1%, range 70.8% to 100%), 76.2% (SD 8.95%, range 62.5% to 95.8%) and 42.6% (SD 17.4%, range 13.5% to 68.8%), respectively. There was no significant correlation between the OPTION scores for the three groups (ICC = -0.323). CONCLUSIONS: The results showed that generally high levels of SDM were perceived by patients and clinicians but lower levels of SDM were scored by the independent observers. However, it could be argued that the patient's perception of SDM is the most important measure as it is their care that is affected by their involvement

Determining the outcomes of post-mastectomy radiation therapy delivered to the definitive implant in patients undergoing one- and two-stage implant-based breast reconstruction: A systematic review and meta-analysis

BACKGROUND: Post-mastectomy radiation therapy (PMRT) is known to increase the complication rate and implant loss in implant-based breast reconstruction. The purpose of this study was to systematically review the literature regarding the outcome of PMRT delivered to the permanent/definitive implant. METHODS: Systematic review and meta-analysis of studies involving immediate implant-based reconstruction and PMRT when delivered to the permanent implant. RESULTS: Seven studies included 2921 patients (520 PMRT, 2401 control). PMRT was associated with significant increase in capsular contracture (7 studies, 2529 patients, 494 PMRT, 2035 control, OR 10.21, 95% CI 3.74 to 27.89, p < 0.00001). In addition, PMRT was associated with a significant increase in revisional surgery (7 studies, 2921 patients, 520 PMRT, 2401 control, OR 2.18, 95% CI 1.33 to 3.57, p = 0.002) and reconstructive failure (6 studies, 2814 patients, 496 PMRT, 2318 control, OR 2.52, 95% CI 1.48 to 4.29, p+0.0007). Moreover, it was associated with a significant reduction in patient satisfaction (4 studies, 468 patients, 138 PMRT, 294 control, OR 0.29, 95% CI 0.15 to 0.57, p = 0.0003) and cosmetic outcome (4 studies, 1317 patients, 238 PMRT, 1009 control, OR 28, 95% CI. 0.11 to 0.67, p = 0.005). CONCLUSIONS: This meta-analysis demonstrates that within the first 5 years, post implant-based reconstruction for those patients who receive PMRT, the rates of adverse events are increased, and there is a significant reduction in patient satisfaction and cosmetic outcome

Tribological behaviour of AZ31 magnesium alloy reinforced by bimodal size B4C after precipitation hardening

This study investigated dry sliding wear properties of AZ31 magnesium alloy and B4C-reinforced AZ31 composites containing 5, 10, and 20 wt.% B4C with bimodal sizes under different loadings (10–80 N) at various sliding speeds (0.1–1 m/s) via the pin-on-disc configuration. Microhardness evaluations showed that when the distribution of B4C particles was uniform the hardness of the composites increased by enhancing the reinforcement content. The unreinforced alloy and the composite samples were examined to determine the wear mechanism maps and identify the dominant wear mechanisms in each wear condition and reinforcement content. For this purpose, wear rates and friction coefficients were recorded during the wear tests and worn surfaces were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry analyses. The determined wear mechanisms were abrasion, oxidation, delamination, adhesion, and plastic deformation as a result of thermal softening and melting. The wear evaluations revealed that the composites containing 5 and 10 wt.% B4C had a significantly higher wear resistance in all the conditions. However, 20 wt.% B4C/AZ31 composite had a lower resistance at high sliding speeds (0.5–1 m/s) and high loadings (40–80 N) in comparison with the unreinforced alloy. The highest wear resistance was obtained at high sliding speeds and low loadings with the domination of oxidative wear

Population pharmacokinetic modelling of indium-based quantum dot nanoparticles: preclinical in vivo studies

There is considerable interest in biomedical applications of quantum dot (QD) nanoparticles, in particular their use as imaging agents for diagnostic applications. In order to investigate the in vivo biodistribution and the potential toxicity of quantum dots (QDs), it is crucial to develop pharmacokinetic (PK) models as basis for prediction of QDs exposure profiles over time. Here, we investigated the in vivo biodistribution of novel indium-based QDs in mice for up to three months after intravenous administration and subsequently developed a translational population PK model to scale findings to humans. This evaluation was complemented by a comprehensive overview of the in vivo toxicology of QDs in rats. The QDs were primarily taken up by the liver and spleen and were excreted via hepatobiliary and urinary pathways. A non-linear mixed effects modelling approach was used to describe blood and organ disposition characteristics of QDs using a multi-compartment PK model. The observed blood and tissue exposure to QDs was characterised with an acceptable level of accuracy at short and long-term. Of note is the fast distribution of QDs from blood into liver and spleen in the first 24 h post-injection (half-life of 28 min) followed by a long elimination profile (half-life range: 47-90 days). This is the first study to assess the PK properties of QDs using a population pharmacokinetic approach to analyse in vivo preclinical data. No organ damage was observed following systemic administration of QDs at doses as high as 48 mg/kg at 24 h, 1 week and 5 weeks post-injection. In conjunction with the data arising from the toxicology experiments, PK parameter estimates provide insight into the potential PK properties of QDs in humans, which ultimately allow prediction of their disposition and enable optimisation of the design of first-in-human QDs studies

Combination of verteporfin-photodynamic therapy with 5-aza-2’-deoxycytidine enhances the anti-tumour immune response in triple negative breast cancer

Introduction: Triple negative breast cancer (TNBC) is a subtype of breast cancer characterised by its high tumourigenic, invasive, and immunosuppressive nature. Photodynamic therapy (PDT) is a focal therapy that uses light to activate a photosensitizing agent and induce a cytotoxic effect. 5-aza-2’-deoxycytidine (5-ADC) is a clinically approved immunomodulatory chemotherapy agent. The mechanism of the combination therapy using PDT and 5-ADC in evoking an anti-tumour response is not fully understood. Methods: The present study examined whether a single dose of 5-ADC enhances the cytotoxic and anti-tumour immune effect of low dose PDT with verteporfin as the photosensitiser in a TNBC orthotopic syngeneic murine model, using the triple negative murine mammary tumour cell line 4T1. Histopathology analysis, digital pathology and immunohistochemistry of treated tumours and distant sites were assessed. Flow cytometry of splenic and breast tissue was used to identify T cell populations. Bioinformatics were used to identify tumour immune microenvironments related to TNBC patients. Results: Functional experiments showed that PDT was most effective when used in combination with 5-ADC to optimize its efficacy. 5-ADC/PDT combination therapy elicited a synergistic effect in vitro and was significantly more cytotoxic than monotherapies on 4T1 tumour cells. For tumour therapy, all types of treatments demonstrated histopathologically defined margins of necrosis, increased T cell expression in the spleen with absence of metastases or distant tissue destruction. Flow cytometry and digital pathology results showed significant increases in CD8 expressing cells with all treatments, whereas only the 5-ADC/PDT combination therapy showed increase in CD4 expression. Bioinformatics analysis of in silico publicly available TNBC data identified BCL3 and BCL2 as well as the following anti-tumour immune response biomarkers as significantly altered in TNBC compared to other breast cancer subtypes: GZMA, PRF1, CXCL1, CCL2, CCL4, and CCL5. Interestingly, molecular biomarker assays showed increase in anti-tumour response genes after treatment. The results showed concomitant increase in BCL3, with decrease in BCL2 expression in TNBC treatment. In addition, the treatments showed decrease in PRF1, CCL2, CCL4, and CCL5 genes with 5-ADC and 5-ADC/PDT treatment in both spleen and breast tissue, with the latter showing the most decrease. Discussion: To our knowledge, this is the first study that shows which of the innate and adaptive immune biomarkers are activated during PDT related treatment of the TNBC 4T1 mouse models. The results also indicate that some of the immune response biomarkers can be used to monitor the effectiveness of PDT treatment in TNBC murine model warranting further investigation in human subjects

Photodynamic Therapy in Primary Breast Cancer

Photodynamic therapy (PDT) is a technique for producing localized necrosis with light after prior administration of a photosensitizing agent. This study investigates the nature, safety, and efficacy of PDT for image-guided treatment of primary breast cancer. We performed a phase I/IIa dose escalation study in 12 female patients with a new diagnosis of invasive ductal breast cancer and scheduled to undergo mastectomy as a first treatment. The photosensitizer verteporfin (0.4 mg/kg) was administered intravenously followed by exposure to escalating light doses (20, 30, 40, 50 J; 3 patients per dose) delivered via a laser fiber positioned interstitially under ultrasound guidance. MRI (magnetic resonance imaging) scans were performed prior to and 4 days after PDT. Histological examination of the excised tissue was performed. PDT was well tolerated, with no adverse events. PDT effects were detected by MRI in 7 patients and histology in 8 patients, increasing in extent with the delivered light dose, with good correlation between the 2 modalities. Histologically, there were distinctive features of PDT necrosis, in contrast to spontaneous necrosis. Apoptosis was detected in adjacent normal tissue. Median follow-up of 50 months revealed no adverse effects and outcomes no worse than a comparable control population. This study confirms a potential role for PDT in the management of early breast cancer