Leopard predation on wild Sichuan snub-nosed monkeys.

Predation is widely recognized as a powerful selective pressure on primate behavior and ecology, although knowledge of predator-prey relationships remains limited partly due to the rarity of directly observed attacks on primates. Here, we describe four confirmed or suspected instances of leopard (Panthera pardus) predation on free-ranging Sichuan (golden) snub-nosed monkeys (Rhinopithecus roxellana), a highly endangered colobine species endemic to China. We recorded predation events and the reactions of monkey group members. We suggest that the evolution of a multilevel society may be an adaptive response by Sichuan snub-nosed monkeys to the risk from leopards as well as other potential predators, one that balances the pressures of predation and intra-species competition and conflict.

Genomic analysis of indigenous goats in Southwest Asia reveals evidence of ancient adaptive introgression related to desert climate.

Understanding how evolutionary pressures related to climate change have shaped the current genetic background of domestic animals is a fundamental pursuit of biology. Here, we generated whole-genome sequencing data from native goat populations in Iraq and Pakistan. Combined with previously published data on modern, ancient (Late Neolithic to Medieval periods), and wild Capra species worldwide, we explored the genetic population structure, ancestry components, and signatures of natural positive selection in native goat populations in Southwest Asia (SWA). Results revealed that the genetic structure of SWA goats was deeply influenced by gene flow from the eastern Mediterranean during the Chalcolithic period, which may reflect adaptation to gradual warming and aridity in the region. Furthermore, comparative genomic analysis revealed adaptive introgression of the KITLG locus from the Nubian ibex ( C. nubiana) into African and SWA goats. The frequency of the selected allele at this locus was significantly higher among goat populations located near northeastern Africa. These results provide new insights into the genetic composition and history of goat populations in the SWA region.

Microbiome changes in the gastric mucosa and gastric juice in different histological stages of Helicobacter pylori-negative gastric cancers.

BACKGROUND: The gastric microbiota in patients with gastric cancer (GC) has received increasing attention, but the profiling of the gastric microbiome through the histological stages of gastric tumorigenesis remains poorly understood, especially for patients with Helicobacter pylori-negative GC (HPNGC). AIM: To characterize microbial profiles of gastric mucosa and juice for HPNGC carcinogenesis and identify distinct taxa in precancerous lesions. METHODS: The 16S rRNA gene analysis was performed on gastric mucosa from 134 Helicobacter pylori-negative cases, including 56 superficial gastritis (SG), 9 atrophic gastritis (AG), 27 intestinal metaplasia (IM), 29 dysplasia (Dys), and 13 GC cases, to investigate differences in gastric microbial diversity and composition across the disease stages. In addition, paired gastric mucosa and juice samples from 18 SG, 18 IM, and 18 Dys samples were analyzed. α-Diversity was measured by Shannon and Chao1 indexes, and ß-diversity was calculated using partial least squares discrimination analysis (PLS-DA). Differences in the microbial composition across disease stages in different sample types were assessed using the linear discriminant analysis effect size. RESULTS: The diversity and composition of the bacterial microbiota in the gastric mucosa changed progressively across stages of gastric carcinogenesis. The diversity of the gastric mucosa microbiota was found to be significantly lower in the IM and Dys groups than in the SG group, and the patients with GC had the lowest bacterial community richness (P < 0.05). Patients with IM and those with Dys had similar gastric mucosa microbiota profiles with Ralstonia and Rhodococcus as the predominant genera. Microbial network analysis showed that there was increasing correlation strength between IM and Dys (|correlation threshold|≥ 0.5, P < 0.05). GC and its precancerous lesions have distinguishable bacterial taxa; our results identified HPNGC-associated bacteria Streptococcaceae and Lactobacillaceae (P < 0.05). Additionally, across precancerous lesion stages from AG to Dys in Helicobacter pylori-negative patients, Burkholderiaceae abundance continuously increased, while Streptococcaceae and Prevotellaceae abundance presented a continuous downward trend. Furthermore, the microbial diversity was higher in gastric juice (P < 0.001) than in the mucosa, while PLS-DA revealed a statistically significant difference between the two groups (ANOSIM, P = 0.001). A significant difference in the microbial structure was identified, with Proteobacteria being more prevalent in the gastric mucosa and Firmicutes being more abundant in gastric juice. CONCLUSION: Our results provide insights into potential taxonomic biomarkers for HPNGC and its precancerous stages and assist in predicting the prognosis of IM and Dys based on the mucosal microbiota profile.

Clinicopathological, Radiological, and Molecular Features of Primary Lung Adenocarcinoma with Morule-Like Components.

BACKGROUND: Morule-like component (MLC) was a rare structure in primary lung adenocarcinoma. We aimed to reveal the clinicopathological, radiological, immunohistochemical, and molecular features of lung adenocarcinoma with MLCs. METHODS: Twenty lung adenocarcinomas with MLCs were collected, and computed tomographic and histological documents were reviewed. Immunohistochemistry, targeted next-generation sequencing, and Sanger sequencing for ß-catenin gene were performed. RESULTS: There were 9 lepidic adenocarcinomas, 8 acinar adenocarcinomas, 2 papillary adenocarcinomas, and 1 minimally invasive adenocarcinoma. Most patients (16/17) were shown a pure solid nodule, and 1 patient was shown a partly solid nodule on chest computed tomography (CT). Nine cases were accompanied with micropapillary components, and 3 were with cribriform components in which 2 suffered a worse prognosis. No significant association was found between the MCLs and the overall survival of lung adenocarcinoma (P = 0.109). The MLCs were often arranged in whorled or streaming patterns. The cells in MLCs showed syncytial and mild appearance. The MLCs were positive for E-cadherin, CK7, TTF-1, napsin-A, vimentin, and ß-catenin (membrane), and negative for CK5/6, p40, p63, Synaptophysin, chromogranin A, and Cdx-2. EGFR mutation, ALK-EML4 fusion, HER2 amplification, and PIK3CA mutation were detected in 16 cases, 2 cases, 1 case, and 1 case, respectively. EGFR mutation was more frequent in adenocarcinomas with MLCs than those without MLCs (P = 0.040). ß-catenin gene mutation was not detected in any patients. CONCLUSIONS: MLC is often observed in the background of acinar, lepidic, and papillary adenocarcinomas. Lung adenocarcinomas with MLCs tend to appear as a solid mass on CT and harbor EGFR gene mutations. The micropapillary components and cribriform components may cause poor prognosis of lung adenocarcinomas with MLCs. Vimentin is always positive in MLCs, and it is a useful marker for the identification of MLCs.

Lymphangiomatosis associated with protein losing enteropathy: A case report.

BACKGROUND: Lymphangiomatosis is a multisystem disorder that is rarely localized to the gastrointestinal tract. Lymphangiomatosis usually has no specific clinical presentation and is easily misdiagnosed. A case report and review of the literature on lymphangiomatosis associated with protein-losing enteropathy will help to improve the overall understanding of this disease. CASE SUMMARY: We report a case of lymphangiomatosis of the bowel and other solid organs. A 78-year-old man presented with recurrent bowel bleeding and protein-losing enteropathy, as well as cystic lesions in the spleen, liver, and kidney. Imaging examinations revealed many cystic lesions on the spleen, liver, kidney, and thickened wall of the ascending colon, as well as pleural effusion and ascites. Colonoscopy revealed a strawberry mucosa, variable spontaneous bleeding, and surface erosion located in the terminal ileum. Several cystic masses with a translucent and smooth surface as well as diffuse white spots were located in the colon. A laterally spreading tumor (LST) was located in the ascending colon. Pathology indicated highly differentiated adenocarcinoma (LST) and lymphangiomatoid dilation, and D2-40 was positive. The final diagnosis was lymphangiomatosis. The patient underwent surgery for LST and then was administered thalidomide 75-150 mg/d. His condition, however, did not improve. He eventually died 6 mo after the initial diagnosis. CONCLUSION: Lymphangiomatosis usually occurs diffusely and can involve many organs, such as the spleen, kidney, liver, lung, mesentery, and bowel. Recurrent bowel bleeding or protein-losing enteropathy is an important indicator that should alert clinicians about the possibility of this disease when it afflicts the bowel. Doctors should improve the medical understanding of lymphangiomatosis.

Different fuel regulation in two types of myofiber results in different antioxidant strategies in Daurian ground squirrels (Spermophilus dauricus) during hibernation.

We previously showed that different skeletal muscles in Daurian ground squirrels (Spermophilus dauricus) possess different antioxidant strategies during hibernation; however, the reason for these varied strategies remains unclear. To clarify this issue, we studied REDD1, FOXO4, PGC-1α, FOXO1 and atrogin-1 proteins to determine the potential cause of the different antioxidant strategies in Daurian ground squirrels during hibernation, and to clarify whether different strategies affect atrophy-related signals. Results showed that the soleus (SOL) muscle experienced intracellular hypoxia during interbout arousal, but no oxidative stress. This may be due to increased PGC-1α expression enhancing antioxidant capacity in the SOL under hypoxic conditions. Extensor digitorum longus (EDL) muscle showed no change in oxidative stress, hypoxia or antioxidant capacity during hibernation. The FOXO1 and PGC-1α results strongly suggested differentially regulated fuel metabolism in the SOL and EDL muscles during hibernation, i.e. enhanced lipid oxidation and maintained anaerobic glycolysis, respectively. Atrogin-1 expression did not increase during hibernation in either the SOL or EDL, indicating that protein synthesis was not inhibited by atrogin-1. Thus, our results suggest that different fuel regulation may be one mechanism related to antioxidant defense strategy formation in different kinds of skeletal muscle fibers of Daurian ground squirrels during hibernation.

Early colon cancer with enteropathy-associated T-cell lymphoma involving the whole gastrointestinal tract: A case report.

BACKGROUND: Enteropathy-associated T-cell lymphoma (EATL) is a rare invasive lymphoma derived from gastrointestinal epithelial T lymphocytes. EATL involving the whole gastrointestinal tract accompanied with early colon cancer is extremely rare. CASE SUMMARY: We present the case of a 67-year-old man with diarrhea for more than 5 mo whose colonoscopy in another hospital showed multiple colonic polyps, which indicated moderate to severe dysplasia and focal early cancer. Therefore, he was referred to our hospital for further endoscopic treatment. Colonoscopy after admission showed that the mucosa of the terminal ileum and the entire colon were slightly swollen and finely granular. Endoscopic mucosal resection was performed for colonic polyps located in the liver flexure of the colon and descending colon, respectively. Histopathological findings revealed diffuse infiltration of medium-sized lymphoid cells in the colonic mucosa and visible lymphoepithelial lesions. The histopathology of the polyp in the descending colon indicated moderately differentiated adenocarcinoma limited to the mucosa with negative resection margins. Additionally, immunohistochemical analysis showed positive staining for CD7 and CD8. Therefore, we arrived at a diagnosis of EATL with early colon cancer. Subsequently, the patient was transferred to the hematology department for chemotherapy. The patient's diarrhea was not significantly relieved after receiving chemotherapy, and he ultimately died of severe myelosuppression. CONCLUSION: EATL should be considered in unexplained chronic diarrhea. EATL progresses rapidly with a poor prognosis, especially when accompanied with early colon cancer.

Different fuel regulation in two types of myofiber results in different antioxidant strategies in Daurian ground squirrels (Spermophilus dauricus) during hibernation.

We previously showed that different skeletal muscles in Daurian ground squirrels (Spermophilus dauricus) possess different antioxidant strategies during hibernation; however, the reason for these varied strategies remains unclear. To clarify this issue, we studied REDD1, FOXO4, PGC-1α, FOXO1, and atrogin-1 proteins to determine the potential cause of the different antioxidant strategies in Daurian ground squirrels during hibernation, and to clarify whether different strategies affect atrophy-related signals. Results showed that the soleus (SOL) muscle experienced intracellular hypoxia during interbout arousal, but no oxidative stress. This may be due to increased PGC-1α expression enhancing antioxidant capacity in the SOL under hypoxic conditions. Extensor digitorum longus (EDL) muscle showed no change in oxidative stress, hypoxia, or antioxidant capacity during hibernation. The FOXO1 and PGC-1α results strongly suggested differentially regulated fuel metabolism in the SOL and EDL muscles during hibernation, i.e., enhanced lipid oxidation and maintained anaerobic glycolysis, respectively. Atrogin-1 expression did not increase during hibernation in either the SOL or EDL, indicating that protein synthesis was not inhibited by atrogin-1. Thus, our results suggest that different fuel regulation may be one mechanism related to antioxidant defense strategy formation in different kinds of skeletal muscle fibers of Daurian ground squirrels during hibernation.

[Intramuscular type of nodular fasciitis: a report of 3 cases and review of literature].

PURPOSE: To retrospectively analyze the clinical characteristics of impacted supernumerary teeth in 115 patients. METHODS: One hundred and fifteen patients with im-pacted supernumerary teeth who were admitted to the Department of Oral and Max-illofacial Surgery of Hefei Stomatological Hospital were selected randomly. The age, sex, number of teeth, location, direction, clinical manifestation, anaes-thesia method and operation time were analyzed retrospectively, T test and Chi-square test were used to determine the statistical differences with SPSS 19.0 software package. RESULTS: Among 115 patients, there were 176 impacted supernu-merary, most of them were in mixed dentition period (66.96%), the sex ratio was 2.29:1, and Most patients (59.1%) had one supernumerary tooth, followed by two supernumerary teeth(33.9%). Most supernumerary teeth were located in the middle of the maxilla (68.2%). Inverted ones were the most common (52.8%). The most common symptoms were delayed eruption, displacement, crowding, torsion and space of the adjacent teeth. 92.2% of patients underwent general anesthesia. The dee-per the locations of impacted supernumerary were, the longer the operation time was. CONCLUSIONS: There are regional characteristics of supernumerary teeth in Hefei City, which can provide a reference for clinical diagnosis and treatment.

Effects of age, sex and manual task on hand preference in wild Rhinopithecus roxellana.

Golden snub-nosed monkeys (Rhinopithecus roxellana), as typical arboreal group-living Old World monkeys, provide an appropriate animal model to research manual laterality and explore the factors affecting hand preference in nonhuman primates. This study investigated hand preference based on 63 subjects and four spontaneous manual tasks (including unimanual and bimanual feeding and grooming), and assessed the effects of age, gender and type of task on handedness in R. roxellana. A population-level left-handedness was found not only in the bimanual coordinated tasks (bimanual feeding and grooming), but also in one unimanual reaching task (unimanual feeding). There were no significant differences between the sexes in either direction or strength of hand preference among any task. However, a significant difference between adults and juveniles was found in the unimanual feeding task. This is the first report on handedness in unimanual and bimanual feeding tasks that require bipedal posture in wild R. roxellana. Furthermore, this study demonstrated spontaneous feeding tasks reported previously only in the quadrupedal posture in this species, supporting the importance of factors such as posture and task complexity in the evolution of primate manual lateralization.

Assembly of ZnII and CdII coordination polymers with different dimensionalities based on the semi-flexible 3-(1H-benzimidazol-2-yl)propanoic acid ligand.

Two new coordination polymers, namely, poly[[µ3-3-(1H-benzimidazol-2-yl)propionato]zinc(II)], [Zn(C10H8N2O2)] n , (1), and poly[bis-[µ2-3-(1H-benzimid-azol-2-yl)propionato]cadmium(II)], [Cd(C10H8N2O2)2] n , (2) have been synthesized from 3-(1H-benzoimidazol-2-yl)propanoic acid ligands through a mixed-ligand synthetic strategy under a solvothermal environment, and studied by single-crystal X-ray diffraction. Complex 1 crystallizes in the ortho-rhom-bic space group Pbca and features a two-dimensional structure formed by a binuclear Zn2O4 core. Complex 2, however, crystallizes in the monoclinic space group P21/c and forms a one-dimensional chain structure. The ZnII and CdII ions have different coordination numbers and the 3-(1H-benzoimidazol-2-yl)propano-ate ligands display different coordination modes. The structures reported here show the importance of the selection of metal ions and suitable ligands.

An infinite two-dimensional hybrid water-chloride network in a 4'-(furan-2-yl)-2,2':6',2''-terpyridine nickel(II) matrix.

A new complex, namely bis-[4'-(furan-2-yl)-2,2':6',2''-terpyridine]-nickel(II) dichloride deca-hydrate, [Ni(C19H13N3O)2]Cl2·10H2O, has been crystallized by solvent evaporation and characterized by single-crystal X-ray diffraction. The coordination environment of the NiII cation is distorted octa-hedral with slight deviations from an idealized geometry. The most intriguing structural feature is an infinite two-dimensional hybrid water-chloride network parallel to (011) constructed by O-H⋯O and O-H⋯Cl hydrogen bonds involving two independent chloride ions and ten independent solvent water mol-ecules with an l-shaped pattern. One of the furyl rings is disordered with a refined occupancy ratio of 0.786 (13):0.214 (13).

Medulloblastoma with Atypical Dynamic Imaging Changes: Case Report with Literature Review.

OBJECTIVE: We analyzed a case of medulloblastoma with atypical dynamic imaging changes retrospectively to summarize the atypical magnetic resonance imaging (MRI) features of medulloblastoma by reviewing the literature. METHODS: An atypical case of medulloblastoma in the cerebellar hemisphere confirmed by pathology was analyzed retrospectively, and the literature about it was reviewed. RESULTS: The radiologic findings of the patient were based on 3 examinations. The first examination showed that the cortex of the bilateral cerebellar hemisphere had diffuse nodular thickening, with a high signal on diffusion-weighted imaging and significant enhancement. Contrast enhancement MRI 1 year later showed the signal of cerebellar hemisphere returned to normal but revealed an enhanced nodule. A reexamination 6 months later showed an irregular mass with a high-density shadow in the cerebellar vermis on CT scan. The T2-weighted image revealed multiple degenerative cysts, and the mass had significant enhancement. CONCLUSION: The radiologic characteristics of atypical medulloblastomas vary in adults and children. Understanding the radiologic characteristics of medulloblastomas, such as MRI features, age of onset, and location of atypical medulloblastomas, can help improve the diagnosis of medulloblastomas.

A one-dimensional silver(I) coordination polymer based on 5-methyl-1,3,4-thiadiazol-2-amine and pyridine-2,3-dicarboxylate.

The bifunctional pyridine-2,3-dicarboxylic acid (H2pdc) ligand has one N atom and four O atoms, which could bind more than one AgI centre with diverse binding modes. A novel infinite one-dimensional AgI coordination polymer, namely catena-poly[[silver(I)-(µ2-pyridine-2,3-dicarboxylato-κ2N:O3)-silver(I)-tris(µ2-5-methyl-1,3,4-thiodiazol-2-amine-κ2N:N')] monohydrate ethanol monosolvate], {[Ag2(C7H3NO4)(C3H5N3S)3]·H2O·C2H5OH}n, has been synthesized using H2pdc and 5-methyl-1,3,4-thiadiazol-2-amine (tda), and characterized by single-crystal X-ray diffraction. One AgI atom is located in a four-coordinated AgN4 tetrahedral geometry and the other AgI atom is in a tetrahedral AgN3O geometry. A dinuclear AgI cluster formed by three tda ligands with a paddelwheel configuration is bridged by the dianionic pdc2- ligand into a one-dimensional coordination polymer. Interchain N-H...O hydrogen bonds extend the one-dimensional chains into an undulating two-dimensional sheet. The sheets are further packed into a three-dimensional supramolecular framework by interchain N-H...O hydrogen bonds.

A dramatic blood plasticity in hibernating and 14-day hindlimb unloading Daurian ground squirrels (Spermophilus dauricus).

We compared the effects of hibernation inactivity and 14-day hindlimb unloading in non-hibernating period on biochemical, rheological, and hematological parameters of blood in Daurian ground squirrels (Spermophilus dauricus). Twenty-four squirrels were randomly divided into four groups: control (CON), hibernation (HIB), post-hibernation (POST), and 14-day hindlimb unloading (HU). The results showed that serum enzymes (L-lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase) activities decreased in HIB, POST, and HU squirrels compared with CON. Total protein (including albumin and globulin) maintained in HIB but decreased in HU compared with CON. Total cholesterol and high-density lipoprotein-cholesterol increased in HIB but maintained in HU and POST compared with CON. Meanwhile, serum creatinine decreased and urea increased in HU compared with CON. All blood ions concentrations were unchanged in HIB, POST, and HU squirrels compared with CON except calcium which increased in HIB compared with CON, and phosphorus which increased in HIB and POST compared with CON. Most of detected serum biochemical analytes in POST recovered to the CON level. Blood viscosity, which was unchanged in all shear rates in HU, increased in HIB and recovered in POST in lower shear rates compared with CON. Erythrocyte and corpuscular volume decreased in HIB and HU but maintained in POST compared with CON. All the routine hematological parameters recovered in POST as compared with CON except platelet, which decreased in HIB and POST but maintained in HU compared with CON. In conclusion, our results suggested a remarkable ability to maintain blood homeostasis in hibernating squirrels.

Synthesis, structure, thermostability and luminescence properties of Zn(II) and Cd(II) coordination polymers based on dimethysuccinate and flexible 1,4-bis(imidazol-1-ylmethyl)benzene ligands.

The design and synthesis of functional coordination polymers is motivated not only by their structural beauty but also by their potential applications. Zn(II) and Cd(II) coordination polymers are promising candidates for producing photoactive materials because these d(10) metal ions not only possess a variety of coordination numbers and geometries, but also exhibit luminescence properties when bound to functional ligands. It is difficult to predict the final structure of such polymers because the assembly process is influenced by many subtle factors. Bis(imidazol-1-yl)-substituted alkane/benzene molecules are good bridging ligands because their flexibility allows them to bend and rotate when they coordinate to metal centres. Two new Zn(II) and Cd(II) coordination polymers based on mixed ligands, namely, poly[[µ2-1,4-bis(imidazol-1-ylmethyl)benzene-κ(2)N(3):N(3')]bis(µ3-2,2-dimethylbutanoato-κ(3)O(1):O(4):O(4'))dizinc(II)], [Zn2(C6H8O4)2(C14H14N4)]n, and poly[[µ2-1,4-bis(imidazol-1-ylmethyl)benzene-κ(2)N(3):N(3')]bis(µ3-2,2-dimethylbutanoato-κ(5)O(1),O(1'):O(4),O(4'):O(4))dicadmium(II)], [Cd2(C6H8O4)2(C14H14N4)]n, have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. Both complexes crystallize in the monoclinic space group C2/c with similar unit-cell parameters and feature two-dimensional structures formed by the interconnection of S-shaped Zn(Cd)-2,2-dimethylsuccinate chains with 1,4-bis(imidazol-1-ylmethyl)benzene bridges. However, the Cd(II) and Zn(II) centres have different coordination numbers and the 2,2-dimethylsuccinate ligands display different coordination modes. Both complexes exhibit a blue photoluminescence in the solid state at room temperature.

A two-dimensional zinc(II) coordination polymer based on mixed dimethyl succinate and bipyridine ligands: synthesis, structure, thermostability and luminescence properties.

From the viewpoint of crystal engineering, the construction of crystalline polymeric materials requires a rational choice of organic bridging ligands for the self-assembly process. Multicarboxylate ligands are of particular interest due to their strong coordination activity towards metal ions, as well as their various coordination modes and versatile conformations. The structural chemistry of dicarboxylate-based coordination polymers of transition metals has been developed through the grafting of N-containing organic linkers into carboxylate-bridged transition metal networks. A new luminescent two-dimensional zinc(II) coordination polymer containing bridging 2,2-dimethylsuccinate and 4,4'-bipyridine ligands, namely poly[[aqua(µ2-4,4'-bipyridine-κ(2)N:N')bis(µ3-2,2-dimethylbutanedioato)-κ(4)O(1),O(1'):O(4):O(4');κ(5)O(1):O(1),O(4):O(4),O(4')-dizinc(II)] dihydrate], {[Zn2(C6H8O4)2(C10H8N2)(H2O)]·2H2O}n, has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction and elemental, IR and thermogravimetric analyses. In the structure, the 2,2-dimethylsuccinate ligands link linear tetranuclear Zn(II) subunits into one-dimensional chains along the c axis. 4,4'-Bipyridine acts as a tethering ligand expanding these one-dimensional chains into a two-dimensional layered structure. Hydrogen-bonding interactions between the water molecules (both coordinated and free) and carboxylate O atoms strengthen the packing of the layers. Furthermore, the luminescence properties of the complex were investigated. The compound exhibits a blue photoluminescence in the solid state at room temperature and may be a good candidate for potential hybrid inorganic-organic photoactive materials.

A new two-dimensional extended adenine and thiophenecarboxylate mixed-ligand zinc(II) complex: synthesis, structure, thermostability and luminescent properties.

The design and preparation of crystalline polymeric materials has attracted increasing attention due to their diverse applications as functional materials in gas storage, separation, catalysis, sensing and photoluminescence. The judicious selection of organic linkers is critical for varying the coordination behaviour of the metal ions and determining the overall characteristics of the networks. A new adenine-based Zn(II) coordination polymer, [Zn(C6H2O4S)(C5H5N5)]n or [Zn(tdc)(9H-ade)] (H2tdc is thiophene-2,5-dicarboxylic acid and ade is adenine), has been prepared hydrothermally and the crystal structure exhibits in its packing two-dimensional (4,4) grid sheets parallel to the ab plane, featuring two distinct square cavities delimited by the two types of ligands and the Zn(II) ions with the dimensions 6.6 × 6.6 and 10.2 × 10.2 Å (based on the Zn...Zn distance). The title complex shows enhanced photoluminescence at 378 nm compared to the free ligands, suggesting that the coordination of H2tdc or adenine to the metal centre effectively increases the rigidity of the ligands and reduces the energy loss by radiative decay of intraligand excited states.