Serostatus of echovirus 11, coxsackievirus B3 and enterovirus D68 in cord blood: The implication of severe newborn enterovirus infection.

BACKGROUND: Maternal transplacental antibody is an important origins of passive immunity against neonatal enterovirus infection. Echovirus 11 (E11) and coxsackievirus B3 (CVB3) are important types causing neonatal infections. There were few investigations of enterovirus D68 (EVD68) infection in neonates. We aimed to investigate the serostatus of cord blood for these three enteroviruses and evaluate the factors associated with seropositivity. METHODS: We enrolled 222 parturient (gestational age 34-42 weeks) women aged 20-46 years old between January and October 2021. All participants underwent questionnaire investigation and we collected the cord blood to measure the neutralization antibodies against E11, CVB3 and EVD68. RESULTS: The cord blood seropositive rates were 18% (41/222), 60% (134/232) and 95% (211/222) for E11, CVB3 and EVD68, respectively (p < 0.001). Geometric mean titers were 3.3 (95% CI 2.9-3.8) for E11, 15.9 (95% CI 12.5-20.3) for CVB3 and 109.9 (95% CI 92.4-131.6) for EVD68. Younger parturient age (33.8 ± 3.6 versus 35.2 ± 4.4, p = 0.04) was related to E11 seropositivity. Neonatal sex, gestational age and birth body weight were not significantly different between the seropositive group and the seronegative group. CONCLUSION: Cord blood seropositive rate and geometric mean titer of E11 were very low, so a large proportion of newborns are susceptible to E11. The circulation of E11 was low after 2019 in Taiwan. A large cohort of immune naïve newborns existed currently due to lack of protective maternal antibodies. It is imminent to monitor the epidemiology of neonates with enterovirus infections and strengthen the relevant preventive policies.

Elevation of inactive cleaved annexin A1 in the neocortex is associated with amyloid, inflammatory and apoptotic markers in neurodegenerative dementias.

Inflammation is usually a tightly regulated process whose termination by mediators including Annexin A1 (AnxA1) results in the resolution of inflammatory responses. In neurodegenerative dementias, chronic neuroinflammation, along with accumulation of aggregated ß-amyloid (Aß) peptides and apoptosis, has long been recognized to be a pathological hallmark; but it is unclear whether a failure of inflammation resolution contributes to this pathophysiological process. In this study, we measured AnxA1 immunoreactivities in postmortem neocortex (Brodmann areas BA9 and BA40) of well characterized Alzheimer's disease (AD), Parkinson disease dementia (PDD) and dementia with Lewy bodies (DLB) patients as well as aged controls. Inactive cleaved AnxA1 was found to be elevated in AD and DLB in BA40. Levels of cleaved AnxA1 also positively correlated with amyloidogenic brain Aß, anti-inflammatory markers such as IL10 and IL13, as well as with the pro-apoptotic marker cleaved caspase-3 in BA40. Our findings suggest that elevated cleaved AnxA1 in neurodegenerative dementias may reflect a failure of inflammation resolution in certain regions of the diseased brain, and also support a mechanistic link between AnxA1 and amyloid pathology, neuroinflammation and apoptosis.

Enterovirus D68 seroepidemiology in Taiwan, a cross sectional study from 2017.

BACKGROUND: Enterovirus D68 (EV-D68) was discovered in 1962 and has unique characteristics compared to the characteristics of other enteroviruses. There were few documented cases before the epidemic in the United States in 2014. The Taiwan Centers for Diseases Control also confirmed that EV-D68 has been endemic, and some cases of acute flaccid myelitis were reported in Taiwan. To understand the current EV-D68 serostatus, we performed an EV-D68 seroepidemiology study in Taiwan in 2017. METHODS: After informed consent was obtained, we enrolled preschool children, 6- to 15-year-old students and 16- to 49-year-old people. The participants underwent a questionnaire investigation and blood sampling to measure the EV-D68 neutralization antibody. RESULTS: In total, 920 subjects were enrolled from the northern, central, southern and eastern parts of Taiwan with a male-to-female ratio of 1.03. The EV-D68 seropositive rate was 32% (26/82) in infants, 18% (27/153) in 1-year-old children, 43% (36/83) in 2-year-old children, 60% (94/156) in 3- to 5-year-old children, 89% (108/122) in 6- to 11-year-old primary school students, 98% (118/121) in 12- to 15-year-old high school students, 100% (122/122) in 16- to 49-year-old women and 100% (81/81) in 16- to 49-year-old males in 2017. Among preschool children, EV-D68 seropositivity was related to age (p for trend <0.0001), size of household ≧4 members (p = 0.037) and kindergarten attendance (p = 0.027). The seropositive rate varied among different geographic regions. CONCLUSION: EV-D68 infection was prevalent, and its seropositive rates increased with age, larger household size and kindergarten attendance among preschool children.

Manifestations of enterovirus D68 and high seroconversion among children attending a kindergarten.

BACKGROUND/PURPOSE(S): Enterovirus D68(EV-D68) is an emerging disease that affects mostly children. There have been few relevant investigations to clarify transmission and seroprevalence within daycares and kindergartens. METHODS: This prospective cohort study investigated respiratory viral transmission among preschool children in a public kindergarten in Taipei City of Taiwan between September 2006 and June 2008. After children were enrolled, daily monitoring of illness and regular biweekly physical examinations were performed. We performed viral isolation to detect acute EV-D68 infection and neutralization tests to detect specific EV-D68 antibodies and to measure the seroprevalence and seroconversion rates. RESULTS: Among 190 kindergarten attendees aged between two to five years old, nine children had acute EV-D68 infection in September 2007. The clinical manifestations included pharyngitis, cough and other unspecified upper respiratory tract infection. None of the infected children had acute flaccid paralysis or severe respiratory illness. The phylogenetic tree of partial viral protein 3 and viral protein 1 was clustered in clade A1. The EV-D68 seropositive rate increased from 19% (25/130) at the beginning to 67% (83/124) at the end of the study. The seroconversion rate of 49 children with initial seronegative and paired sera was 73% (36/49). CONCLUSIONS: A high seroconversion rate (73%) for EV-D68 was found among kindergarten attendees, which indicates preschool-aged children are highly susceptible to EV-D68 infection and that the disease burden may be extremely underestimated. Once EV-D 68 circulates, preventive measures may be advocated, especially within kindergartens or daycares, to reduce transmission and subsequent development of severe cases.

Random mixed-metal Co1-xNix single-chain magnets with simultaneous azide, carboxylate and tetrazolate bridges.

This paper reports the magnetic properties of a series of isomorphous metal-organic frameworks based on random heterometallic Co1-xNix chains with simultaneous azide, carboxylate and tetrazolate bridges. All the mixed-metal compounds show intrachain FM interactions, field-induced metamagnetism, and SCM-like slow magnetic relaxation. These behaviors are quite different from the parent Co(ii) and Ni(ii) materials, and even a small amount of metal replacement can cause significant magnetic changes. The static properties such as AF ordering, metamagnetic critical field and the hysteresis parameters show complicated composition dependence. Most interestingly, the mixed-metal systems can show a higher blocking temperature than the Co(ii) compound, suggesting that the randomly distributed metal ions have synergistic effects on slow relaxation of magnetization. This is phenomenologically associated with the competitive effects of Δτ and τo.

Association of EV71 3C polymorphisms with clinical severity.

OBJECTIVES: Enterovirus 71 (EV71) may cause neurological and fatal cases. EV71 3C plays an important role on viral replication and possess proteolysis activity. To delineate pathogenesis of EV71 virulence, we studied EV71 3C genetics, protease activity and correlated the results with clinical severity. METHODS: EV71 cases were collected; 3C of EV71 was sequenced and linked with clinical severity. 3C protease activity, viral replication rates of EV71 infectious clones with different 3C and 3C interaction with host proteins were analyzed. RESULTS: The polymorphisms of EV71 3C at the 79th amino acid were associated with clinical severity. About 26% (62/234) patients infected by EV71 with wild-type 3C (T79) had neurological involvement but 78% (25/32) patients infected by EV71 with mutant 3C (T79V) did (p < 0.001). There was no significant difference of protease activity among the different 3C variants. EV71 with mutant 3C (T79V) had the highest viral replication rate and the mutant 3C (T79V) had weaker interaction with TRIM21, a component of antibody-dependent intracellular neutralization, than the other mutants (T79I and T79A). CONCLUSION: We found that 3C polymorphisms were associated with clinical severity and viral replication, which might be related to 3C interaction with important host proteins such as TRIM21.

Ferro- or antiferromagnetic interactions controlled by ditopic or chelating auxiliary ligands in 3D metal-organic frameworks.

Three 3D Co(ii) metal-organic frameworks of the general formula [Co(DNNDC)(NN)]n were reported, where DNNDC = 1,5-dinitronaphthalene-3,7-dicarboxylate and NN = bridging or chelating dipyridyl ligands. The MOFs exhibit similar 3D [Co(DNNDC)]n frameworks in which double-carboxylate-bridged [Co(OCO)2]n chains are cross-linked by naphthalene backbones. The bridging dipyridyl ligands [4,4'-bipyridine (bpy) and 1,2-bis(4-pyridyl)ethane (bpe)] serve as additional linkers between the chains to generate a reinforced framework with new net topology, while the chelating ligand 1,10-phenanthroline (phen) reinforces the frameworks through π-π stacking and C-HO interactions. Remarkably, varying the auxiliary ligand leads to a change in the sign of the magnetic exchange through the double carboxylate bridge: the MOFs with the ditopic bpy and bpe ligands show ferromagnetic interactions, while the one with the chelating phen ligand shows antiferromagnetic exchange. The difference in magnetic exchange is attributable to the subtle change in the coordination conformation of the carboxylate bridge.

Transmission of acute infectious illness among cases of Kawasaki disease and their household members.

BACKGROUND/PURPOSE: Kawasaki disease (KD) is a disease of unknown cause and the causative agent is most likely to be infectious in nature. To investigate the household transmission pattern of infectious illness and etiology, we thus initiated a prospective case and household study. METHODS: We enrolled KD cases and their household members from February 2004 to September 2008. The KD cases and their household members accepted questionnaire-based interviews of the contact history, signs of infection, and symptoms to check whether clusters of infectious illness occurred. RESULTS: A total of 142 KD cases and 561 household members were enrolled. Among the 142 KD cases, 136 cases (96%) were typical KD, and six (4%) were atypical KD. Of the 561 household members, 17% were siblings, 46% were parents, 18% were grandparents, and the others were cousins or babysitters. Prior to the onset of their KD illness, 66% (94/142) KD cases had contact with ill household members. On the same day of the onset of KD cases' illness, 4% (6/142) KD cases had household members with illness. After KD cases' disease onset, 70% (100/142) KD cases had at least one other family member with illness. Overall, 61% (343/561) of all the household members had acute infectious illness during KD cases' acute stage, and 92% (130/142) of the families had clusters of infectious illness. CONCLUSION: A total of 66% KD cases had positive contact with ill household members prior to their disease onset and 92% of families had clusters of infectious illness, so KD is strongly associated with infections.

Copper(II) coordination polymers with azide and bipyridine-based zwitterionic carboxylate ligands: structures and magnetism.

Two novel Cu(II) coordination polymers, [Cu4O(L(1))4(N3)2]n(ClO4)4n·3nH2O (1) and [Cu7(L(2))2(N3)14]n (2), have been synthesized from two zwitterionic carboxylate ligands, 1-carboxylatomethyl-4,4'-bipyridinium (L(1)) and 1-carboxylatomethyl-4,4'-dimethylenedipyridinium (L(2)). Compound 1 exhibits interpenetrated 3D diamond networks in which the unusual µ4-O-centred tetrahedral Cu4 clusters with peripheral 1,1-N3 and COO bridges are cross-linked by 4,4'-dipyridinium-1-methylene spacers. In compound 2, pentanuclear and dinuclear units with double azide bridges are linked into a unique 2D layer by µ3-1,1,3-N3, (1,1-N3)(COO) and the organic backbone of the zwitterionic ligand. Magnetic studies reveal that compound 1 exhibits ferromagnetic coupling through (µ4-O)(1,1-N3) and antiferromagnetic coupling through the µ4-O-only and (µ4-O)(COO)2 pathways. Compound 2 exhibits ferromagnetic coupling within the (1,1-N3)2 bridged polynuclear units and weak antiferromagnetic coupling through µ3-1,1,3-N3, and (1,1-N3)(COO) between the units.

Viral infections associated with Kawasaki disease.

BACKGROUND/PURPOSE: Kawasaki disease (KD) is a disease of unknown cause. To investigate the infectious etiology of Kawasaki disease, we initiated a prospective case-control study to investigate possible links between common viral infections and Kawasaki disease. METHODS: We enrolled 226 children with KD and 226 age- and sex-matched healthy children from February 2004 to March 2010. Throat and nasopharyngeal swabs were taken for both viral isolation and polymerase chain reaction (PCR) for various viruses. RESULTS: The mean age of the 226 KD cases was 2.07 years, and the male to female ratio was 1.43 (133 boys to 93 girls). Their mean fever duration was 7.5 days with a mean peak temperature of 39.7°C. In addition to the typical symptoms of fever, neck lymphadenopathy, lip fissure and/or strawberry tongue, skin rash, nonpurulent bulbar conjunctivitis, palm/sole erythema, and induration followed by periungual desquamation, these KD cases also exhibited cough (69%), rhinorrhea (58%), and diarrhea (45%). Cases of KD had a significantly higher positive rate of viral isolation in comparison with the control group (7.5% vs. 2.2%, p = 0.02). Compared with the control group, cases of KD were more likely to have overall positive rates of viral PCR (50.4% vs. 16.4%, p < 0.001) and for various viruses including enterovirus (16.8% vs. 4.4%, p < 0.001), adenovirus (8.0% vs. 1.8%, p = 0.007), human rhinovirus (26.5% vs. 9.7%, p < 0.001), and coronavirus (7.1% vs. 0.9%, p = 0.003). CONCLUSION: We found that some common respiratory viruses, such as adenoviruses, enteroviruses, rhinoviruses, and coronaviruses, were associated with KD cases.

Atypical hand-foot-mouth disease in children: a hospital-based prospective cohort study.

BACKGROUND: In 2010, we observed children with atypical presentations of hand-foot-mouth disease (HFMD), such as rashes on earlobes and faces, or bullae on trunks and bilateral limbs. Hyperpigmentation later developed as the bullous lesions crusted. Thus, we intended to study the etiology of the illness and the phylogeny of the pathogens. METHOD: Patients were prospectively enrolled in a tertiary medical center in Taipei, Taiwan. The definition of atypical HFMD includes symptoms of acute viral infection with either of the following presentations: (1) maculopapular rashes presenting on the trunks, buttocks or facial areas, or (2) large vesicles or bullae on any sites of the body. Patients were classified into two groups according to vesicle sizes by two pediatricians at different points in time. The large vesicle group was defined as having vesciculobullous lesions ≥ 1 cm in diameter; the small rashes group had maculopapular rashes < 1cm in diameter. Two throat swabs were collected from each patient for virus isolation and reverse transcription polymerase chain reactions. RESULTS: We enrolled 101 patients between March and December 2010. The mean age of the participants was 3.3 ± 3.0 years (median age: 2.5 years, range: 21 days-13.5 years). The ratio of males to females was 1.8 to 1. All samples were enterovirus-positive, including coxsackievirus A6 (80%), coxsackievirus A16 (6%), enterovirus 71 (1%), coxsackievirus A5 (1%) and 12 non-typable enterovirus (12%). Bullous fluid aspirated from 2 patients also grew coxsackievirus A6. Among the patients infected with coxsackievirus A6, 54% (45/81) had bullae, compared to 25% (5/20) of those having non-coxsackievirus A6 infections (P=0.02). Fourteen cases had myoclonic jerks and one boy was diagnosed with febrile convulsions. None had complications or sequelae. Phylogenetic analysis showed the strains in Taiwan in 2010 shared more commonality with strains from Finland in 2009 (GenBank: FJ870502-FJ870508), and were close to those circulating in Japan in 2011 (GenBank: AB649286-AB649291). CONCLUSIONS: Coxsackievirus A6 infections may cause atypical manifestations of HFMD, including vesicles or papules on faces or bullae on trunks. These features could provide valuable information to distinguish this versatile enterovirus infection from other virus-induced vesiculobullous diseases.

Unusual composition dependence of magnetic relaxation for Co(II)(1-x)Ni(II)(x) chain-based metal-organic frameworks.

A series of isomorphous 3D Co(II)(1-x)Ni(II)(x) MOFs based on ferromagnetic chains show SCM-type slow relaxation and the Co-rich system can exhibit a higher blocking temperature than both Co(II) and Ni(II) parent materials.

Clinical features and phylogenetic analysis of Coxsackievirus A9 in Northern Taiwan in 2011.

BACKGROUND: Coxsackievirus A9 (CA9) was one of the most prevalent serotype of enteroviral infections in Taiwan in 2011. After several patient series were reported in the 1960s and 1970s, few studies have focused on the clinical manifestations of CA9 infections. Our study explores and deepens the current understanding of CA9. METHODS: We analyzed the clinical presentations of 100 culture-proven CA9-infected patients in 2011 by reviewing their medical records and depicted the CA9 phylogenetic tree. RESULTS: Of the 100 patients with culture-proven CA9 infections, the mean (SD) age was 4.6 (3.4) years and the male to female ratio was 1.9. For clinical manifestations, 96 patients (96%) had fever and the mean (SD) duration of fever was 5.9 (3.4) days. Sixty one patients (61%) developed a skin rash, and the predominant pattern was a generalized non-itchy maculopapular rash without vesicular changes. While most patients showed injected throat, oral ulcers were found in only 19 cases (19%), among whom, 6 were diagnosed as herpangina. Complicated cases included: aseptic meningitis (n=8), bronchopneumonia (n=6), acute cerebellitis (n=1), and polio-like syndrome (n=1). Phylogenetic analysis for current CA9 strains is closest to the CA9 isolate 27-YN-2008 from the border area of mainland China and Myanmar. CONCLUSIONS: The most common feature of CA9 during the 2011 epidemic in Taiwan is generalized febrile exanthema rather than herpangina or hand, foot, and mouth disease. Given that prolonged fever and some complications are possible, caution should be advised in assessing patients as well as in predicting the clinical course.

Synthesis, structures, and magnetic properties of four copper compounds with 2,2'-dinitrobiphenyl-4,4'-dicarboxylate.

Four copper(II) coordination polymers of 2,2'-dinitrobiphenyl-4,4'-dicarboxylic acid (H(2)dnbpdc), with or without 4,4'-bipyridyl (bipy) as co-ligand, were synthesized under hydrothermal conditions and characterized crystallographically and magnetically. They are formulated as [Cu(2)(dnbpdc)(OH)(2)](n) (1), [Cu(Hdnbpdc)(2)(bipy)](n)·2nH(2)O (2), [Cu(2)(dnbpdc)(2)(bipy)(H(2)O)(2)](n)·2nH(2)O (3) and [Cu(3)(dnbpdc)(2)(bipy)(OH)(2)(H(2)O)](n)·nH(2)O (4). Compound 1 exhibits a 2D coordination network, in which infinite [Cu(µ-OH)(µ-COO)](n) chains are linked by the backbones of the dnbpdc(2-) ligands. Magnetic studies indicated antiferromagnetic coupling through the mixed hydroxo and carboxylate bridges between Cu(II) ions. In 2, mononuclear Cu(II) centers are linked by Hdnbpdc(-) and bipy ligands into 2D grid-like layers. Compound 3 also consists of 2D grid-like coordination layers, which however are based on aqua-bridged Cu(2)(µ-OH(2))(2) units. Magnetic studies showed that the magnetic coupling through the double aqua bridges is antiferromagnetic. Compound 4 exhibits a 3D framework in which [Cu(OH)(COO)](n) chains are linked by bipy and dnbpdc(2-) ligands. The chain has a complicated bridging network involving µ(3)-OH, µ(2)-OH and µ-COO, and magnetic studies revealed overall antiferromagnetic interactions within the chain.

Seroprevalence of enterovirus 71 and no evidence of crossprotection of enterovirus 71 antibody against the other enteroviruses in kindergarten children in Taipei city.

BACKGROUND/PURPOSE: Enterovirus 71 (EV71) infection may cause severe neurological and cardiopulmonary complications, especially in preschool children. This study is to investigate the seroprevalence and seroconversion of EV71, and the crossprotection of EV71 antibody against other enteroviruses among kindergarteners. METHODS: Overall 228 children in a public kindergarten were enrolled during two academic years, 2006 and 2007, in Taipei, Taiwan and we measured their EV71 neutralizing antibody. When the participants had herpangina; hand, foot and mouth disease (HFMD); febrile illness or respiratory symptoms, throat swabs were sampled and processed for viral culture and enterovirus real-time reverse transcriptase polymerase chain reaction (RT-PCR). Questionnaires, completed by the participants' guardians, surveyed the history of allergy and annual incidence of symptoms related to enterovirus infection. RESULTS: Seropositive rates of EV71 were 20% (32/163) in 2006 and 6% (4/65) in 2007. The rate of EV71 seropositivity increased with age (p < 0.01) in 2006 but it did not differ between genders (p = 0.14). No seroconversion was observed from 2006 to 2007. Herpangina occurred in 64% of children with EV71 seropositivity and 48% of those without EV71 antibodies (p = 0.12). Non-71 enterovirus infection, confirmed by viral study, occurred in 53% (19/36) of the EV71-seropositive children and in 53% (102/192) of EV71-seronegative children (p = 0.89). No participants had EV71 infection during the study period. CONCLUSION: EV71 did not frequently circulate in Taipei City from September 2006 to June 2008. Presence of EV71 neutralizing antibody was not associated with lower incidence of enterovirus infection caused by non-71 serotypes.

Household transmission of Pandemic (H1N1) 2009 Virus, Taiwan.

During August-November 2009, to investigate disease transmission within households in Taiwan, we recruited 87 pandemic (H1N1) 2009 patients and their household members. Overall, pandemic (H1N1) 2009 virus was transmitted to 60 (27%) of 223 household contacts. Transmission was 4× higher to children than to adults (61% vs. 15%; p<0.001).

Manganese(II)-carboxylate-pseudohalide systems derived from 1,4-bis(4-carboxylatopyridinium-1-methylene)benzene: structures and magnetism.

The reactions of manganese(II) acetate or perchlorate, sodium azide or sodium cyanate, and the zwitterionic dicarboxylate ligand 1,4-bis(4-carboxylatopyridinium-1-methylene)benzene (L) under different conditions yielded three different Mn(II) coordination polymers with mixed carboxylate and azide (or cyanate) bridges: {[Mn (L(1))(0.5)(N(3))(OAc)]·3H(2)O}(n) (1), {[Mn(4)(L(1))(N(3))(8)(H(2)O)(4)(CH(3)OH)(2)]·[L(1)]}(n) (2), and {[Mn(3)(L(1))(NCO)(6)(H(2)O)(4)]·[L(1)]·[H(2)O](2)}(n) (3). The compounds exhibit diverse structures and magnetic properties. In 1, the 1D uniform anionic [Mn(N(3))(COO)(2)](n) chains with the (µ-EO-N(3))(µ-COO)(2) triple bridges (EO = end-on) are interlinked by the dipyridinium L ligands into highly undulated 2D layers. Magnetic studies on 1 reveal that the mixed triple bridges induce antiferromagnetic coupling between Mn(II) ions. Compounds 2 and 3 consist of 1D neutral polymeric chains and co-crystallized zwitterions, and the chains are formed by the L ligands interlinking linear polynuclear units. The polynuclear unit in 2 is tetranuclear with (µ-EO-N(3))(2) as central bridges and (µ-EO-N(3))(2)(µ-COO) as peripheral bridges, while that in 3 is trinuclear with (µ-NCO)(2)(µ-COO) bridges. Magnetic studies demonstrate that the magnetic coupling through the mixed azide/isocyanate and carboxylate bridges in 2 and 3 is antiferromagnetic. An expression of magnetic susceptibility based on a 2-J model for linear tetranuclear systems of classical spins has been deduced and applied to 2.

Magnetic ordering in three-dimensional metal-organic frameworks based on carboxylate bridged square-grid layers.

Three isomorphous metal-organic frameworks of formula [M(ppdc)(H(2)O)(2)](n) [M = Mn(II), Fe(II), and Co(II)] were synthesized from sodium p-phenylenediacrylic (Na(2)ppdc). Crystallographic studies revealed that the compounds are layer-pillared 3D frameworks in which the square-grid M(II) layers with single carboxylate bridges are interlinked by long organic spacers with large interlayer separations of about 13 Å. Magnetic investigations indicated that they all display intralayer antiferromagnetic interactions through the carboxylate bridges in the unusual skew-skew coordination mode but the bulk behaviors are quite different. The Co(II) compound, like most compounds containing similar M-O-C-O-M layers, shows no 3D magnetic ordering down to 2 K, while the Mn(II) and Fe(II) compounds exhibit spin-canted ordering, behaving as a weak ferromagnet (T(C) = 3.8 K) and a metamagnet (T(N) = 3.8 K, H(c) = 650 Oe), respectively. Spin-canted ordering is still a rarity in this series of materials. Magnetostructural comparisons with analogous compounds indicate that the occurrence of spin-canted ordering can be related to the uncommon skew-skew and anti-anti coordination modes of carboxylate bridges, which induce stronger antiferromagnetic interactions than the common syn-anti mode.

Synthesis, structures, and magnetic properties of transition metal compounds with 2,2'-dinitrobiphenyl-4,4'-dicarboxylate and N,N'-chelating ligands.

Solvothermal reactions of Co(II), Ni(II), Zn(II) salts with 2,2'-dinitrobiphenyl-4,4'-dicarboxylate (dnpdc) and 2,2'-bipyridyl-like chelating ligands yielded five compounds formulated as [Co(dnpdc)(bipy)](n)·nH(2)O (1), [M(dnpdc)(phen)](n) (2, M = Co; 3, M = Ni; 4, M = Zn) and [Co(dnpdc)(biql)](n)·2nH(2)O (5) (bipy = 2,2'-bipyridine, phen = 1,10-phenanthroline and biql = 2,2'-biquinoline). With bipy or phen as coligands, compounds 1-4 exhibit isomorphous 3D M(dnpdc) metal-organic frameworks in which double carboxylate bridged chains are interlinked by the backbones of the dicarboxylate ligands. The bipy or phen ligands are involved in interchain hydrogen bonding or π-π interactions to form 1D zipper-like arrays in the rhombic channels of the frameworks, playing a templating role and determining the channel dimensions. The biql coligand is too bulky for the 1D double carboxylate bridged chain and the rhombic channel. Instead, in compound 5, the dnpdc ligands link metal ions into 1D zigzag metal-organic chains and the biql ligands are arranged into 2D (6,3) arrays through extensive π-π stacking interactions. In compounds 1-3, the double carboxylate bridges in the nonplanar syn-skew conformation mediate ferromagnetic interactions along the chains, while the chelating ligands provide supramolecular pathways for interchain antiferromagnetic interactions. The π-π interactions in 5 also evoke weak antiferromagnetic interactions.

An outbreak of coxsackievirus A16 infection: comparison with other enteroviruses in a preschool in Taipei.

BACKGROUND/PURPOSE: The transmission rate of enteroviruses in young children remains unclear. Therefore, we carried out active surveillance in preschool children to investigate the transmission rate and clinical manifestation of enteroviruses. METHODS: From September 2006 to December 2008, we monitored infectious diseases in children 2(-3 years of age) in a preschool in Taipei. If any child had a febrile illness or symptoms/signs of enteroviral infection [e.g. herpangina or hand-foot-and-mouth disease (HFMD)], we performed viral isolation and enterovirus polymerase chain reaction. VP1 sequencing was performed to define their serotypes. We also collected clinical data and analyzed transmission rates. RESULTS: There were eight episodes of enterovirus infection during the study period. The serotypes included coxsackievirus A4 (CA4), CA2 and CA16. The transmission rates of CA4 and CA2 among children in same class were 26% and 35%, respectively. Between November 28 and December 12, 2008, 13/21 (61.9%) children contracted herpangina and/or HFMD. The average age was 2.82 (range, 2.43-3.39) years. CA16 was detected in 10/13 (76.9%) of the throat swabs by polymerase chain reaction VP1 genotyping. Compared with previous CA2 and CA4 outbreaks, CA16 had a significantly higher transmission rate (p = 0.035) and resulted in more cases of HFMD (p < 0.001). The transmission duration of coxsackie A viruses within the same class ranged from 12 to 40 days. CONCLUSION: Compared with CA2 and CA4, CA16 infections resulted in more cases of HFMD and had significantly higher transmission rates in preschoolers.