"The role of Chinese and Indian women as immigrants and workers in colonial Malaya is examined using data from censuses, immigration records, official reports and secondary sources. The article discusses the main types of work of female immigrants and their contribution to the economic development of colonial Malaya during the late nineteenth and early twentieth centuries in an attempt to redress the neglect of female immigrants' economic role in Malaya's history. Comparisons between male and female immigrants' labor and between Chinese and Indian immigrants, are drawn to highlight the different conditions of migration and labor for the different groups of immigrants."
Seventeen patients with small cell lung cancer (SCLC) were treated with cyclophosphamide, adriamycin and vincristine (CAV) combination chemotherapy. The overall response rate was 76.5% with 47% achieving complete response and 29.5% partial response. In limited and extensive stage disease, complete response was achieved in 67% and 36.5% respectively. Chinese were the predominant ethnic group affected (82%). Six patients presenting with superior vena cava obstruction responded significantly to CAV chemotherapy alone. Median survival for patients with extensive disease was 7.4 months. All patients with limited disease were still alive. Two relapsed patients with limited disease achieved significant response to VP-16/Cisplatin combination chemotherapy.
Twelve patients with advanced inoperable non-small cell lung cancer (NSCLC) were treated with mitomycin, vinblastine and cisplatin (MVP) combination chemotherapy. The overall response rate was 33% (4 partial responses and no complete response) with a median survival of seven months. One responder above subsequently achieved complete remission following successful resection of his tumour and is still alive 14 months after initial chemotherapy. Responses were observed in patients with good performance status and limited disease. Side-effects were generally well tolerated and manageable. MVP is an effective regimen and the low response rate achieved here as compared to other centres is also discussed.
This was a preliminary study to test for the presence of multiple antibiotic-resistant extended spectrum β-lactamase (ESBL) producing bacteria in Malaysian urban surface waters. Although the literature review revealed several published papers on clinical ESBL isolates in Malaysia, none were found on ESBL isolates obtained from local surface waters.
A prospective comparative study was carried out on thirty-seven consecutive patients presenting with bleeding oesophageal varices at University Hospital, Kuala Lumpur. All patients received injection sclerotherapy if active bleeding was seen at the time of initial endoscopy, followed by repetitive courses of sclerotherapy to obliterate the varices. Predominant aetiological factors were hepatitis-B cirrhosis (43%) and alcoholic cirrhosis (30%). Chinese ethnic group accounted for 62.5% of hepatitis-B cirrhotics and Indian 73% of alcoholic cirrhotics. After excluding patients lost to follow-up, analysis of the remaining thirty-four patients showed reduced long-term survival in patients with Child's C disease. Log-rank analysis of survival curves between hepatitis-B cirrhosis and alcoholic cirrhosis in patients with Child's C liver disease showed no significant difference in long-term survival (p = 0.07). However, six deaths were seen in hepatitis-B cirrhosis compared to one death in alcoholic cirrhosis in the first eight months of follow-up. Most patients died from progressive liver failure. Median survival for Child's C hepatitis-B cirrhosis was 7.5 months whereas this had not been reached for Child's C alcoholic cirrhosis (median follow-up 11.6 months). We conclude that variceal haemorrhage in Child's C hepatitis-B cirrhosis is a bad prognostic sign and is associated with reduced survival with a median survival of 7.5 months despite control of the variceal bleed.
Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH.
Tea can inhibit the attachment of Streptococcus mutans to surfaces and subsequent biofilm formation. Five commercial tea extracts were screened for their ability to inhibit attachment and biofilm formation by two strains of S. mutans on glass and hydroxyapatite surfaces. The mechanisms of these effects were investigated using scanning electron microscopy (SEM) and phytochemical screening. The results indicated that extracts of oolong tea most effectively inhibited attachment and extracts of pu-erh tea most effectively inhibited biofilm formation. SEM images showed that the S. mutans cells treated with extracts of oolong tea, or grown in medium containing extracts of pu-erh tea, were coated with tea components and were larger with more rounded shapes. The coatings on the cells consisted of flavonoids, tannins and indolic compounds. The ratio of tannins to simple phenolics in each of the coating samples was ∼3:1. This study suggests potential mechanisms by which tea components may inhibit the attachment and subsequent biofilm formation of S. mutans on tooth surfaces, such as modification of cell surface properties and blocking of the activity of proteins and the structures used by the bacteria to interact with surfaces.
The Mn(III) atom in the title complex, [Mn(C(18)H(18)N(2)O(4))(CHO(2))(H(2)O)]·2H(2)O, is O,N,N',O'-chelated by the deproton-ated Schiff base; the four chelating atoms form an approximate square, with the O atoms of the water mol-ecule and the formate ion in axial positions above and below the square plane. Two metal-bearing mol-ecules are linked by an O-H(water)⋯O hydrogen bond about a center of inversion, generating a hydrogen-bonded dinuclear species; adjacent dinuclear units are linked through the lattice water mol-ecules, forming a three-dimensional network.
The environment at the Sn(IV) atom in the title compound, [Sn(C(6)H(11))(2)(C(18)H(11)BrN(2)O(3))], is distorted trigonal-bipyramidal, with the two cyclo-hexyl groups and the imino N atom forming the equatorial plane. The axial O-Sn-O angle is 155.97 (9)°. The presence of an intra-molecular O-H⋯N hydrogen bond in the Schiff base ligand helps to stabilize the overall structure.
The Sn(IV) atom in the title compound, [Sn(CH(3))(2)(C(18)H(11)BrN(2)O(3))], shows a distorted cis-C(2)NO(2)Sn trigonal-bipyramidal coordination geometry, with an axial O-Sn-O angle of 155.27 (9)°. The presence of an intra-molecular O-H⋯N hydrogen bond between the amido N atom and hydr-oxy H atom in the Schiff base ligand helps to stabilize the overall mol-ecular structure.
The five-coordinate Sn(IV) atoms in the two crystallographically independent mol-ecules of the title compound, [Sn(C(4)H(9))(2)(C(19)H(13)ClN(2)O(3))], are in distorted cis-C(2)NO(2)Sn trigonal-bipyramidal coordination environments. The tridentate dianion of the Schiff base, N'-[1-(5-chloro-2-oxidophen-yl)ethyl-idene]-3-hy-droxy-2-naphtho-hydrazide, displays inter-molecular O-H⋯N hydrogen bonding, which stabilizes the overall compound.
In the title compound, [Sn(C(4)H(9))(2)(C(11)H(12)BrNO(4))], the Schiff base ligand chelates to the Sn(IV) atom through the two deprotonated hy-droxy groups, as well as through the N atom, to confer an overall cis-C(2)SnNO(2) trigonal-bipyramidal geometry at the Sn(IV) atom [C-Sn-C = 129.92 (9)°]. The remaining methyl-enehy-droxy groups engage in O-H⋯O hydrogen bonding with the O atoms of adjacent mol-ecules, leading to infinite supra-molecular chains propagating in [001].
The title compound, [Sn(C(6)H(11))(3)(C(17)H(25)O(3)S)], exists as a monomeric mol-ecule with the Sn(IV) atom in a distorted tetra-hedral C(3)O coordination geometry. The presence of two bulky tert-butyl groups on the carboxyl-ate prevents any hydrogen-bonding inter-actions involving the hy-droxy group.
In the title tetra-nuclear tin(IV) complex, [Sn(4)(CH(3))(8)(C(20)H(22)N(2)O(4))Cl(2)O(2)], there are three completely different tin-atom coordinations. One metal atom (site symmetry 2) adopts a distorted penta-gonal-bipyramidal SnC(2)N(2)O(3) coordination arising from the N,N',O,O'-tetra-dentate deprotonated Schiff base, two methyl groups in the axial sites and a μ(3)-O atom that also bonds to two further Sn atoms. Two symmetry-equivalent Sn atoms adopt very distorted SnC(2)O(4) arrangements that could be described as penta-gonal-bipyramidal with one equatorial vertex missing and the C atoms in the axial site. The final Sn atom (site symmetry 2) adopts an SnC(2)Cl(2)O trigonal-bipyramidal arrangement, with Cl atoms in the axial sites. As well as the two Sn atoms, one O atom lies on a twofold rotation rotation axis, and another is disordered about the axis. The terminal eth-oxy group is disordered over two sets of sites with equal occupancy.
Bacterial attachment to abiotic surfaces can be explained as a physicochemical process. Mechanisms of the process have been widely studied but are not yet well understood due to their complexity. Physicochemical processes can be influenced by various interactions and factors in attachment systems, including, but not limited to, hydrophobic interactions, electrostatic interactions and substratum surface roughness. Mechanistic models and control strategies for bacterial attachment to abiotic surfaces have been established based on the current understanding of the attachment process and the interactions involved. Due to a lack of process control and standardization in the methodologies used to study the mechanisms of bacterial attachment, however, various challenges are apparent in the development of models and control strategies. In this review, the physicochemical mechanisms, interactions and factors affecting the process of bacterial attachment to abiotic surfaces are described. Mechanistic models established based on these parameters are discussed in terms of their limitations. Currently employed methods to study these parameters and bacterial attachment are critically compared. The roles of these parameters in the development of control strategies for bacterial attachment are reviewed, and the challenges that arise in developing mechanistic models and control strategies are assessed.
The increase in prevalence of antimicrobial-resistant bacteria (ARB) is currently a serious threat, thus there is a need for new antimicrobial compounds to combat infections caused by these ARB. An antimicrobial-producing bacterium, Burkholderia paludis was recently isolated and was able to produce a type of siderophore with antimicrobial properties, later identified as pyochelin. The chelating ability of pyochelin has been well-characterized but not for its antimicrobial characteristics. It was found that pyochelin had MIC values (MBC values) of 3.13 µg/mL (6.26 µg/mL) and 6.26 µg/mL (25.00 µg/mL) against three Enterococcus strains and four Staphylococcus strains. Pyochelin was able to inhibit E. faecalis ATCC 700802 (a vancomycin-resistant strain) in a time and dose dependent manner via killing kinetics assay. It was demonstrated that pyochelin enhanced the production of intracellular reactive oxygen species (ROS) over time, which subsequently caused a significant increase in malondialdehyde (MDA) production (a marker for lipid peroxidation) and ultimately led to cell death by disrupting the integrity of the bacterial membrane (validated via BacLight assay). This study has revealed the mechanism of action of pyochelin as an antimicrobial agent for the first time and has shown that pyochelin might be able to combat infections caused by E. faecalis in the future.
We report the draft genome sequences of two Paenibacillus species with cellulose-degrading abilities isolated from landfill leachate. An array of genes putatively involved in cellulose degradation have been identified in both genome sequences, which can benefit various biotechnological industries.
Tea has been suggested to promote oral health by inhibiting bacterial attachment to the oral cavity. Most studies have focused on prevention of bacterial attachment to hard surfaces such as enamel.
In the title compound, [Sn(C(6)H(11))(2)(C(19)H(14)N(2)O(3))], the Sn(IV) atom is O,N,O' chelated by the deprotonated Schiff base ligand and exists in a cis-trigonal-bipyramidal environment, completed by the two cyclohexyl ligands.
In the title ion-pair, C(22)H(29)Cl(2)N(4)O(2) (+)·C(2)F(3)O(2) (-), ammonium-carboxyl-ate N-H⋯O hydrogen bonds link two cations and two anions about a centre of inversion to generate a hydrogen-bonded tetramer. In the cation, one of the imino N atoms is protonated and donates a hydrogen bond to the O atom of the adjacent chloro-phenyl ring. The other imino N atom acts as a hydrogen-bond acceptor from a phenolate O atom.