The rational search for selective anticancer derivatives of the peptide Trichogin GA IV: a multi-technique biophysical approach

Peptaibols are peculiar peptides produced by fungi as weapons against other microorganisms. Previous studies showed that peptaibols are promising peptide-based drugs because they act against cell membranes rather than a specific target, thus lowering the possibility of the onset of multi-drug resistance, and they possess non-coded alpha-amino acid residues that confer proteolytic resistance. Trichogin GA IV (TG) is a short peptaibol displaying antimicrobial and cytotoxic activity. In the present work, we studied thirteen TG analogues, adopting a multidisciplinary approach. We showed that the cytotoxicity is tuneable by single amino-acids substitutions. Many analogues maintain the same level of non-selective cytotoxicity of TG and three analogues are completely non-toxic. Two promising lead compounds, characterized by the introduction of a positively charged unnatural amino-acid in the hydrophobic face of the helix, selectively kill T67 cancer cells without affecting healthy cells. To explain the determinants of the cytotoxicity, we investigated the structural parameters of the peptides, their cell-binding properties, cell localization, and dynamics in the membrane, as well as the cell membrane composition. We show that, while cytotoxicity is governed by the fine balance between the amphipathicity and hydrophobicity, the selectivity depends also on the expression of negatively charged phospholipids on the cell surface

Information and communication technology integration in an international high school: the influence of leadership.

Doctoral Degree. University of KwaZulu-Natal, Durban.Information and communication technology (ICT) integration in teaching and learning has become an imperative worldwide. However, this remains problematic due to various factors in different contexts. Often, the extent and success of ICT integration depends on the school leadership hence this study explored ICT integration in an international high school with a focus on the influence of leadership. A qualitative case study was done with 13 participants from one international high school. Data were generated through interviews and document analysis to understand how ICT integration was enacted, the leadership influence and why the school enacted ICT integration in the way it did. The qualitative data were analysed through open coding followed by axial coding to identify salient themes. The theories of technology organisation environment and transformational leadership were used as a lens to make sense of the findings. The results show that the school’s ICT vision and policy informed resource provision and integration in various sectors of the school life. ICT integration was a driver for active learning, information management and school communication. There was decentralisation of responsibilities, strategic ICT resourcing, and regular professional development activities to upskill staff. ICT integration was enacted in response to different stakeholder expectations and to sustain effectiveness and efficiency in school operations. Based on the findings of this study, a needs-based approach to ICT integration leadership is proposed. The needs stem from the curriculum, people, school functionality, and the educational context. Empirical research to test this approach is necessary to develop a better understanding of ICT integration leadership

Post-Occupancy Evaluation and IEQ Measurements from 64 Office Buildings: Critical Factors and Thresholds for User Satisfaction on Thermal Quality

The indoor environmental quality (IEQ) of buildings can have a strong influence on occupants’ comfort, productivity, and health. Post-occupancy evaluation (POE) is necessary in assessing the IEQ of the built environment, and it typically relies on the subjective surveys of thermal quality, air quality, visual quality, and acoustic quality. In this research, we expanded POE to include both objective IEQ measurements and the technical attributes of building systems (TABS) that may affect indoor environment and user satisfaction. The suite of three tools, including user satisfaction survey, workstation IEQ measurements, and TABS in the National Environmental Assessment Toolkit (NEAT) has been deployed in 1601 workstations in 64 office buildings, generating a rich database for statistical evaluation of possible correlations between the physical attributes of workstations, environmental conditions, and user satisfaction. Multivariate regression and multiple correlation coefficient statistical analysis revealed the relationship between measured and perceived IEQ indices, interdependencies between IEQ indices, and other satisfaction variables of significance. The results showed that overall, 55% of occupants responded as “satisfied” or “neutral”, and 45% reported being “dissatisfied” in their thermal quality. Given the dataset, air temperature in work area, size of thermal zone, window quality, level of temperature control, and radiant temperature asymmetry with façade are the critical factors for thermal quality satisfaction in the field. As a result, the outcome of this research contributes to identifying correlations between occupant satisfaction, measured data, and technical attributes of building systems. The presented integrated IEQ assessment method can further afford robust predictions of building performance against metrics and guidelines for IEQ standards to capture revised IEQ thresholds that impact building occupants’ satisfaction.</jats:p

Tecniche di attacco e difesa per sistemi firewall

L’obiettivo principale di questa tesi è di analizzare alcuni software e tecniche di sicurezza informatica. In particolare vengono descritti alcuni firewall, fra cui il packet filter, e il comando iptables che serve per la realizzazione del firewall stesso. Uno degli argomenti principali dell’elaborato è il port knocking, esso è un sistema per modificare dinamicamente le regole del firewall tramite l’invio di tentativi di connessione a una sequenza prestabilita di porte chiuse. In particolare viene mostrato come configurare tale servizio di port knocking e vengono fatti alcuni esempi di cattiva configurazione che renderebbero tale servizio poco efficiente. Nella tesi vengono inoltre descritte alcune tecniche di attacco, fra cui l’attacco DoS e DDoS, e alcuni metodi per mitigare tali tentativi di danneggiamento del sistema. La parte finale dell’elaborato mostra esempi pratici di attacco e difesa del sistema. In particolare viene mostrato come configurando in maniera intelligente il firewall sia possibile difendere il sistema dai tentativi di intrusione o di danneggiamento da parte di un utente esterno

Unexpected Hospital Admissions from a Remote Outpatient Surgicenter

Background: A remote nonhospital outpatient surgical facility in the western suburbs of Chicago has been functioning for ten years. A review of their consecutive patients and admission rate was carried out from the day of opening.Design: A retrospective study of all patients admitted from the facility to the hospital is presented.Methods: 158,408 surgical diagnostic and therapeutic procedures were performed over a ten-year period.Results: 128 patients were admitted to the hospital for treatment of their problems consequent to treatment at the Center for Surgery. The causes of admission included pain, nausea and vomiting, cardiac, respiratory and bleeding considerations.Conclusions: Outpatient surgical treatment may be provided on a large-scale basis away from the hospital with low hospital admission rates and low complication rates. The patients thus are able to return to their homes on the same day of the procedure in an efficient, economic, and less timeconsuming manner

ANALISIS PENGARUH VARIASI TEKANAN GAS DAN PERSENTASE KETEBALAN LAPISAN BOUNDING DAN COATING PADA PROSES REBUILD-UP MATERIAL BAJA AISI 1045 DENGAN METODE ARC SPRAY TERHADAP TINGKAT KEREKATAN ANTAR LAPISAN

Each engine component has the durability that can decrease and wear due to continuous friction. The thermal spray method is an alternative that is used. The type of thermal spray that is found in the industry is Arc Spray. However, the peeling of the coating metal with the substrate is one of the problems. In this study, the variables that have contributed to the peeling of the coating layer were taken. The variables compared are the total thickness of the bounding and coating layers of 1 mm with a percentage of 50% : 50% and 30% : 70%. Another variation is gas pressure of 2 Bar, 3 Bar and 4 Bar in rebuild-up process of AISI 1045. Specimens with thickness percentage of 30% : 70% have significant difference in tensile strength value compared to the thickness percentage of 50% : 50% with an average difference of 5.02 MPa; 4.8975 MPa and 3.29 MPa in specimens with a gas pressure of 2 bar; 3 bars; 4 bars. The influences of thickness of bound and top coat have percentage effect 21.12% on each layer. As the gas pressure increases, the bonding value is higher because the higher gas, the smaller porosity which is proved by microstructural tests

Approaches in breeding for high quality protein maize

Maize is the principal crop and major staple food in the most African and South American countries. The main problem in human nutrition in developing countries, and in livestock feed in developed countries, is insufficient production and poor quality of cereal proteins. In the case of maize, due to the very low content of essential amino acids lysine and tryptophan in grain endosperm, biological value is very low, which is main limiting factor of common maize in human nutrition and feeding of monogastric animals. Quality protein maize (QPM) can help in solving of this problem. Maize production also faces serious constraints caused by agro-ecological conditions and poor socio-economic situation. To alleviate the effect of the constraints, selected genotypes with more desirable traits and appropriate field-plot techniques to create multiple-stress conditions, were used. It was found that, in downy mildew nursery distance up to 35 m from spreader plot is providing sufficient down load of spores for plant infection, provided that the testing breeding materials are planted towards to down-stream direction of the dominant wind. Using these breeding approaches large number of early, white and flint synthetics, composites and inbred lines were created with resistance or tolerance to downy mildew (DMR), maize streak virus (SR) and drought (DT). Created genotypes exhibited very good kernel modification and yield potential under low and normal inputs. In the case of synthetics and composites, besides tolerance to multiple stress factors, they were competing in yield with local QPM and normal maize checks. In the case of created inbred lines high combining ability was exhibited both in non-conventional and conventional maize hybrids. Trial data revealed that in the most cases the best entries were over-yielding the best checks