METAMORPHOSIS OF THE LARVA OF THE POLYCHAETE ARENICOLA CRISTATA. MORPHOLOGY OF THE ‘HOUR-GLASS’ STAGE

The constricted ‘waist’ of the metamorphosing larva of the polychaete Arenicola cristata is described, using light and electron microscopy. The constriction is shown to be the consequence of the discharge and collapse of a post-trochal ring of epithelial cells which remain as functional components of the post-metamorphic juvenile. Morphological differentiation of neuro-effector and interneuronal contacts is initiated at this time. Muscular and neural changes are discussed in terms of their role in effecting metamorphosis.     

The ‘other side’ of embedded ness: A case‐study of the interplay of economy and ethnicity

As interest in ethnics and their entrepreneurial activities has grown in recent years, sociologists have come to emphasize the importance of ethnic social structures as the source of actions propelling business growth. In a sign of convergence with the ‘new economic sociology’, recent literature suggests that embeddedness in ethnic networks and communities leads to cooperative, if not conformist, behaviour among ethnic economic actors. This article looks at the ‘other side’ of embeddedness, through a case‐study of African‐American, Caribbean, Korean and white construction contractors in New York City. I argue that, in construction, the embeddedness of economic behaviour in ongoing social relations among a myriad of social actors impedes access to outsiders. Embeddedness contributes to the liabilities of newness that all neophytes encounter, breeding a preference for established players with track records. However, the convergence of economic and ethnic ties has a further baneful effect, since outsiders also fall outside those networks that define the industrial community. While African‐American, Caribbean and Korean outsiders all experience these barriers in similar ways, they differ in the adaptive strategies that they have pursued. African Americans appear to be most disadvantaged, in part because they have been the most exposed to the social closure that results from the mobilization of white ethnics’ social capital. By contrast, Caribbeans and Koreans entered the labour market in societies where racial domination played little or no role in labour market outcomes ‐ a considerable asset since construction skills are transferable from one society to another. The Koreans appear to be the most embedded in ethnic networks, through which they secure jobs and skilled labour, though class factors play a role here as well and even the Koreans must reach out beyond the ethnic community for a clientele. By contrast, ethnic solidarity operates less powerfully among the black contractors, who are tied to a community where intra‐ethnic diversity and internal competition have grown as a result of immigration. In the absence of an ethnic market, black'entrepreneurs turn to the state, whose requirements and dependence on union labour expose black builders to risks from which their Korean counterparts are sheltered.     

A critical note on ‘exclusive recognition’

Cenk Saracoglu conceptualizes the antipathy towards Kurdish migrants manifesting in certain cities of Turkey since the early 2000s as ‘exclusive recognition’ in his article ‘“Exclusive recognition”: the new dimensions of the question of ethnicity and nationalism in Turkey’ published in Ethnic and Racial Studies 32(4). According to the author, these recent developments represent ‘a historically specific ethnicization process’ and its sources cannot be found directly and only in historical discourses and policy of mainstream Turkish nationalism. In this note, I contradict the author's claims by asserting that the recent manifestations of anti-Kurdish sentiments are an extension of the ongoing policies of Turkish national identity based on Turkish nationalism.     

‘Our fellow Africans make our lives hell’: the lives of Congolese and Nigerians living in Johannesburg

Xenophobia in post-apartheid South Africa has become a major issue. Much of the hostility is directed at Africans from countries north of Southern Africa who are often easily distinguishable due to their physical features, distinctive dress and inability to speak the indigenous languages. This article focuses on immigrants and asylum seekers from two countries, Nigeria and the Democratic Republic of Congo. Both groupings have experienced significant antagonism and prejudice from the local population, more especially from black South Africans. The article describes and analyses the interaction of the two groupings in question with the local populace and authorities. What is argued is that during the apartheid era the restrictions on black immigration meant that the number of black foreigners was limited. Since 1990, however, there has been a substantial increase in illegal and legal migration from Southern African countries and countries further north. This increase, in a context of growing unemployment and crime, limited infrastructural growth and fiscal resources, has intensified xenophobia against foreign Africans. The article is mainly based on in-depth interviews with Nigerian and Congolese informants living in Johannesburg's inner city.     

Impact of winter pruning of pomegranate trees on Aphis punicae (Hemiptera,Aphididae) and its natural enemies in Tunisia

Winter pruning is a cultural practice used to modify vegetative growth, which is likely to affect the development of pests. However, it has been poorly defined as a cultural method for diminishing the population levels of the pomegranate aphid Aphis punicae (Hemiptera, Aphididae) in pomegranate orchards. This study aimed to evaluate the impact of winter pruning of pomegranate on A. punicae population and their natural enemies. The results showed that winter pruning significantly decreased the population of A. punicae (p < 0.05) in pomegranate. Also, number of natural enemies decreased in pomegranate trees after winter pruning. This technical practice affects the number of winged and wingless individuals, the mean relative growth rate, the specific age of the population and the infestation rate. Winter pruning for A. punicae control in pomegranate orchards is highly recommended.     

The discovery of the benzazepine class of histamine H3 receptor antagonists

This Letter describes the discovery of a novel series of H₃ receptor antagonists. The initial medicinal chemistry strategy focused on deconstructing and simplifying an early screening hit which rapidly led to the discovery of a novel series of H₃ receptor antagonists based on the benzazepine core. Employing an H₃ driven pharmacodynamic model, the series was then further optimised through to a lead compound that showed robust in vivo functional activity and possessed overall excellent developability properties.     

Quinones bearing non-steroidal anti-inflammatory fragments as multitarget ligands for Alzheimer’s disease

The anti-amyloid properties shared by several quinones inspired the design of a new series of hybrids derived from the multi-target drug candidate memoquin (1). The hybrids consist of a central benzoquinone core and a fragment taken from non-steroidal anti-inflammatory drugs, connected through polyamine linkers. The new hybrids retain the potent anti-aggregating activity of the parent 1, while exhibiting micromolar AChE inhibitory activities. Remarkably, 2, 4, (R)-6 and (S)-6 were Aβ aggregation inhibitors even more potent than 1. The balanced amyloid/cholinesterase inhibitory profile is an added value that makes the present series of compounds promising leads against Alzheimer’s disease.     

Novel racemic tetrahydrocurcuminoid dihydropyrimidinone analogues as potent acetylcholinesterase inhibitors

The synthesis of racemic tetrahydrocurcumin- (THC-), tetrahydrodemethoxycurcumin- (THDC-) and tetrahydrobisdemethoxycurcumin- (THBDC-) dihydropyrimidinone (DHPM) analogues was achieved by utilizing the multi-component Biginelli reaction in the presence of copper sulphate as a catalyst. The evaluation of acetylcholinesterase inhibitors for Alzheimer’s disease of these compounds showed that they exhibited higher inhibitory activity than their parent analogues. THBDC–DHPM demonstrated the most potent inhibitory activity with an IC₅₀ value of 1.34 ± 0.03 μM which was more active than the approved drug galanthamine (IC₅₀ = 1.45 ± 0.04 μM).     

Discovery of novel indolinone-based,potent, selective and brain penetrant inhibitors of LRRK2

Mutations in leucine-rich repeat kinase-2 (LRRK2) are the most common genetic cause of Parkinson’s disease (PD). The most frequent kinase-enhancing mutation is the G2019S residing in the kinase activation domain. This opens up a promising therapeutic avenue for drug discovery targeting the kinase activity of LRRK2 in PD. Several LRRK2 inhibitors have been reported to date. Here, we report a selective, brain penetrant LRRK2 inhibitor and demonstrate by a competition pulldown assay in vivo target engagement in mice.     

Conformational restriction approach to BACE1 inhibitors II: SAR study of the isocytosine derivatives fixed with a cis-cyclopropane ring

To improve the efficacy of the conformationally restricted BACE1 inhibitors, structural modifications were investigated using two strategies: (a) modification of the terminal aromatic ring and (b) insertion of a spacer between the aromatic rings. In the latter approach, another type of inhibitor 17 bearing an ethylene spacer between two aromatic rings was found to exhibit good BACE1 inhibitory activity, while the corresponding conformationally unrestricted compound 25 showed no activity. This result revealed an interesting effect of a conformational restriction with a cyclopropane ring.