Design of experiments to study the impact of process parameters on droplet size and development of non-invasive imaging techniques in tablet coating

Atomisation of an aqueous solution for tablet film coating is a complex process with multiple factors determining droplet formation and properties. The importance of droplet size for an efficient process and a high quality final product has been noted in the literature, with smaller droplets reported to produce smoother, more homogenous coatings whilst simultaneously avoiding the risk of damage through over-wetting of the tablet core. In this work the effect of droplet size on tablet film coat characteristics was investigated using X-ray microcomputed tomography (XμCT) and confocal laser scanning microscopy (CLSM). A quality by design approach utilising design of experiments (DOE) was used to optimise the conditions necessary for production of droplets at a small (20 μm) and large (70 μm) droplet size. Droplet size distribution was measured using real-time laser diffraction and the volume median diameter taken as a response. DOE yielded information on the relationship three critical process parameters: pump rate, atomisation pressure and coating-polymer concentration, had upon droplet size. The model generated was robust, scoring highly for model fit (R2 = 0.977), predictability (Q2 = 0.837), validity and reproducibility. Modelling confirmed that all parameters had either a linear or quadratic effect on droplet size and revealed an interaction between pump rate and atomisation pressure. Fluidised bed coating of tablet cores was performed with either small or large droplets followed by CLSM and XμCT imaging. Addition of commonly used contrast materials to the coating solution improved visualisation of the coating by XμCT, showing the coat as a discrete section of the overall tablet. Imaging provided qualitative and quantitative evidence revealing that smaller droplets formed thinner, more uniform and less porous film coats

Inhibition of Competence Development, Horizontal Gene Transfer and Virulence in Streptococcus pneumoniae by a Modified Competence Stimulating Peptide

Competence stimulating peptide (CSP) is a 17-amino acid peptide pheromone secreted by Streptococcus pneumoniae. Upon binding of CSP to its membrane-associated receptor kinase ComD, a cascade of signaling events is initiated, leading to activation of the competence regulon by the response regulator ComE. Genes encoding proteins that are involved in DNA uptake and transformation, as well as virulence, are upregulated. Previous studies have shown that disruption of key components in the competence regulon inhibits DNA transformation and attenuates virulence. Thus, synthetic analogues that competitively inhibit CSPs may serve as attractive drugs to control pneumococcal infection and to reduce horizontal gene transfer during infection. We performed amino acid substitutions on conserved amino acid residues of CSP1 in an effort to disable DNA transformation and to attenuate the virulence of S. pneumoniae. One of the mutated peptides, CSP1-E1A, inhibited development of competence in DNA transformation by outcompeting CSP1 in time and concentration-dependent manners. CSP1-E1A reduced the expression of pneumococcal virulence factors choline binding protein D (CbpD) and autolysin A (LytA) in vitro, and significantly reduced mouse mortality after lung infection. Furthermore, CSP1-E1A attenuated the acquisition of an antibiotic resistance gene and a capsule gene in vivo. Finally, we demonstrated that the strategy of using a peptide inhibitor is applicable to other CSP subtype, including CSP2. CSP1-E1A and CSP2-E1A were able to cross inhibit the induction of competence and DNA transformation in pneumococcal strains with incompatible ComD subtypes. These results demonstrate the applicability of generating competitive analogues of CSPs as drugs to control horizontal transfer of antibiotic resistance and virulence genes, and to attenuate virulence during infection by S. pneumoniae

Predictors and severity of injury in assaults with barglasses and bottles

Background: Although glasses and bottles are frequently used as weapons in assaults, there is little knowledge on which prevention strategies can be based. Design: Scrutiny of a random sample of 1288 criminal injury compensation applications. Objective: To identify predictors and relative severity of glass and bottle injury. Method: Injury site, severity, treatment, and demographic characteristics of victims and assailants were studied with reference to awards from the UK national Criminal Injuries Compensation Authority (CICA). Main outcome measures: Gender of victims and assailants, injury sites, treatment, and award (UK pounds) as indices of injury severity. Results: Annual CICA awards to all victims of assaults in licensed premises during 1996–98 amounted to £4.08 million (for all glass/bottle assaults: £1.15 million = 28%). The mean cost of 746 glass assaults was £2347, compared with £2007 for 542 injuries from bottle assaults (mean difference £340; p<0.01). This difference largely reflected more eye injuries with glasses (26 cases: 3% of all glass assaults) than with bottles (eight cases: 1% of all bottle assaults). Bottle assault was significantly associated with unidentified assailants and scalp injuries; whereas glass injury was significantly linked to pub opening hours (midday to midnight), Thursdays, eye and face injuries, and treatment requiring sutures. Mean age of bottle assault victims (26.1 years) was lower than of glass victims (27.3 years; p<0.01), and same gender assaults were more frequent than between gender assaults for both bottle (p<0.001) and glass (p<0.001) assaults. Female victims were allocated to lower compensation awards more frequently than male victims; this was the case for both bottle (p<0.05) and glass (p<0.01) assaults. Conclusions: Assaults with bottles caused less serious injury and resulted in lower compensation costs. Injury distribution was linked to victim gender and weapon choice, but not to assailant gender. Prevention strategies should focus on both bottle and glass assaults and should take account of the setting and time in which drinking occurs

Vessel ultrastructure in APP23 transgenic mice after passive anti-Aβ immunotherapy and subsequent intracerebral hemorrhage

Passive immunization of amyloid precursor protein (APP) transgenic mice with anti-amyloid beta (Aβ) antibodies was shown to reduce Aβ-deposition in brain and to improve cognition. However, immunotherapy may also be accompanied by a significant increase in the frequency of intracerebral hemorrhages. Because hemorrhages are associated with amyloid-laden vessels, this raises the question whether high concentrations of anti-Aβ antibodies may directly or indirectly lead to a structural destabilization of the vessel wall. To address this point, transmission electron microscopy was performed and the ultrastructure of bleeding and non-bleeding vessels in immunized and non-immunized APP23 transgenic animals was analyzed. To localize bleeding vessels, hemosiderin-positive macrophages were visualized by pre-embedding Perl's Berlin Blue histochemistry. Vessels were analyzed morphologically, anomalies evaluated and quantified. Bleeding vessels were, furthermore, reconstructed in three dimensions to analyze the spatial distribution of amyloid deposits and other pathological changes of the vessel wall. This in-depth morphological analysis revealed that bleeding vessels in immunized as well as in non-immunized APP23 mice were surrounded by a higher number of macrophages compared to non-bleeding vessels in the same animals. However, no differences in the number of macrophages or other structural parameters, such as amyloid deposition, were observed between bleeding vessels of immunized and non-immunized mice. No pathologies which may indicate impending bleeding were observed in the vascular wall of non-bleeding vessels. We conclude, that the increased hemorrhage frequency observed after passive immunization with anti-Aβ antibodies does not lead to overt structural changes in the vessel wall of APP23 transgenic mice. Minor structural alterations of the vessel wall, however, cannot be excluded due to the sample size of our study and the high complexity of the three-dimensional vessel wall ultrastructure

The ethical ambivalence of resistant violence: notes from postcolonial south Asia

In the face of mounting militarism in south Asia, this essay turns to anti-state, ‘liberatory’ movements in the region that employ violence to achieve their political aims. It explores some of the ethical quandaries that arise from the embrace of such violence, particularly for feminists for whom political violence and militarism is today a moot point. Feminist responses towards resistant political violence have, however, been less straightforward than towards the violence of the state, suggesting a more ambivalent ethical position towards the former than the latter. The nature of this ambivalence can be located in a postcolonial feminist ethics that is conceptually committed to the use of political violence in certain, albeit exceptional circumstances on the basis of the ethical ends that this violence (as opposed to other oppressive violence) serves. In opening up this ethical ambivalence – or the ethics of ambiguity, as Simone de Beauvoir says – to interrogation and reflection, I underscore the difficulties involved in ethically discriminating between forms of violence, especially when we consider the manner in which such distinctions rely on and reproduce gendered modes of power. This raises particular problems for current feminist appraisals of resistant political violence as an expression of women's empowerment and ‘agency’