Search

The last decade has seen a tremendous expansion of the field of heterogenized molecular catalysis, especially with the growing interest in metal-organic frameworks and related porous hybrid solids. With successful achievements in the transfer from molecular homogeneous catalysis to heterogenized processes come the necessary discussions on methodologies used and a critical assessment on the advantages of heterogenizing molecular catalysis. Here we use the example of nickel-catalyzed ethylene oligomerization, a reaction of both fundamental and applied interest, to review heterogenization methodologies of well-defined molecular catalysts within porous solids while addressing the biases in the comparison between original molecular systems and heterogenized counterparts.

Wastewater-based epidemiology has emerged as a viable tool for monitoring disease prevalence in a population. This paper details a time series machine learning (TSML) method for predicting COVID-19 cases from wastewater and environmental variables. The TSML method utilizes a number of techniques to create an interpretable, hypothesis-driven framework for machine learning that can handle different nowcast and forecast lengths. Some of the techniques employed include:•Feature engineering to construct interpretable features, like site-specific lead times, hypothesized to be potential predictors of COVID-19 cases.•Feature selection to identify features with the best predictive performance for the tasks of nowcasting and forecasting.•Prequential evaluation to prevent data leakage while evaluating the performance of the machine learning algorithm., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Published by Elsevier B.V.)

Bean rust is a devastating disease of snap beans in Sri Lanka. Our study endeavored to develop snap beans with resistance to Uromyces appendiculatus , the bean rust pathogen reported to have numerous virulent races. Accordingly, we needed a detailed understanding of the virulence of U . appendiculatus and to identify genes conferring effective rust resistance. To investigate the virulence, we collected leaves of snap bean with rust symptoms from four snap bean producing districts of Sri Lanka. From these samples we established 57 single pustule isolates. Each isolate was inoculated on a set of 12 differential cultivars, six from the Andean and six from the Middle American gene pools of common bean. The virulence of the isolates segregated into four distinct groups that comprised the first four reported races of U. appendiculatus in Sri Lanka, 23-5, 31-1, 31-11, and 63-21. All races were significantly more virulent on the Andean than on the Middle American differential cultivars. PI 1819966, a Middle American differential cultivar containing the Ur-11 gene, conferred resistance to all four races. Three other Middle American cultivars were resistant to three races. Conversely, five Andean differential cultivars were susceptible to all four races. PI 160418 was the only Andean differential cultivar with resistance to three races. The results suggested that rust resistance genes from the Middle American differential cultivars could be combined in different ways with the resistance of Andean PI 260418 to develop snap bean varieties with broad resistance to all races of U. appendiculatus in Sri Lanka., Competing Interests: The author(s) declare no conflict of interest.

Heterogenization of molecular catalysts via their immobilization within extended structures often results in a lowering of their catalytic properties due to a change in their coordination sphere. Metal-organic polyhedra (MOP) are an emerging class of well-defined hybrid compounds with a high number of accessible metal sites organized around an inner cavity, making them appealing candidates for catalytic applications. Here, we demonstrate a design strategy that enhances the catalytic properties of dirhodium paddlewheels heterogenized within MOP (Rh-MOP) and their three-dimensional assembled supramolecular structures, which proved to be very efficient catalysts for the selective photochemical reduction of carbon dioxide to formic acid. Surprisingly, the catalytic activity per Rh atom is higher in the supramolecular structures than in its molecular sub-unit Rh-MOP or in the Rh-metal-organic framework (Rh-MOF) and yields turnover frequencies of up to 60 h -1 and production rates of approx. 76 mmole formic acid per gram of the catalyst per hour, unprecedented in heterogeneous photocatalysis. The enhanced catalytic activity is investigated by X-ray photoelectron spectroscopy and electrochemical characterization, showing that self-assembly into supramolecular polymers increases the electron density on the active site, making the overall reaction thermodynamically more favorable. The catalyst can be recycled without loss of activity and with no change of its molecular structure as shown by pair distribution function analysis. These results demonstrate the high potential of MOP as catalysts for the photoreduction of CO 2 and open a new perspective for the electronic design of discrete molecular architectures with accessible metal sites for the production of solar fuels.

Hypnale hypnale, Hypnale zara and Hypnale nepa are the three species of Hump nosed pit vipers that are implicated in human bites in Sri Lanka. H. zara and H. nepa are two endemic species to the country. The objective of the study was to characterize epidemiology and clinical features after different Hump nosed pit viper species bites. A prospective observational study was conducted in Base Hospital Deniyaya from 2013 to 2015. Hump nosed pit viper as the offending snake was identified when the victims brought live or dead specimens. Species identification of dead specimen was done by a herpetologist. Clinical details were recorded during the hospital stay. 83 Hump nosed pit viper bite patients (19-81 years) were studied. Fifty two dead specimens were identified as 39 of H. zara and 13 of H. hypnale by the herpetologist. No H. nepa was identified. Thirty one live snakes were identified as Hump nosed pit vipers and released in to the wild. Envenoming was reported throughout the year. Eighty (96.4%) were daytime bites. Hands (43.4%), feet (55.4%) and arms (1.2%) were affected sites. Sixty two (74.7%) were bitten in tea plantations. All had pain over bite site. Overall, sixty nine (83.1%) had local swelling, seven (8.4%) extensive limb swelling, nineteen (22.9%) haemorrhagic blisters, and seven (8.4%) regional lymphadenopathy. Four (4.8%) patients had incoagulable blood by 20WBCT. H. zara bites had 28.2% haemorrhagic blisters, 7.7% extensive limb swelling and 2.6% coagulopathy. H. hypnale bites had 7.7% each extensive limb swelling and coagulopathy and 23.1% haemorrhagic blisters. None developed elevated serum creatinine. Neurotoxicity was not noted. Hump nosed pit viper bites caused substantial morbidity. Risk factors included day time outdoor activities and occupation. Pain, extensive limb swelling, bite site swelling, haemorrhagic blisters, regional lymphadenopathy and coagulopathy were prominent clinical features. Nephrotoxicity and neurotoxicity were notably absent. Clinical features varied depending on the species implicated., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Green pit viper (Trimeresurus trigonocephalus) is endemic to Sri Lanka and bites are reported from tropical rain forest and plantation areas. As scant data exists on clinico-epidemiological features of Sri Lankan green pit viper bite, objective of this study was to address this knowledge gap. A prospective observational study was conducted in Base Hospital Deniyaya from October 2013 to September 2015. Green pit viper as the offending snake was identified when the victims brought live or dead specimens. When the specimen was not available, green pit viper was identified by the victim pointing to preserved specimens and photographs of green pit viper and different similar appearing snakes. Clinical details were recorded during the hospital stay. Twenty four green pit viper bite patients (17-68 years) were studied. All cases were daytime bites despite green pit viper being a nocturnally active snake. Sixteen patients (67%) were bitten while they were working in tea plantation. Hands (42%), feet, (33%), forearms (8%), legs (8%), thighs (4%) and shoulders (4%) were the sites of bites. Thirteen (54%) had extensive limb swelling. Nine (38%) had local swelling and two had no swelling. Three (12.5%) developed haemorrhagic blisters. Four (17%) had regional lymphadenopathy. Two (8%) developed non clotting blood by the TWBCT. Green pit viper bites caused substantial morbidity. Risk factors included day time outdoor activities in bordering villages of tropical rain forests and occupation. Pain, extensive limb swelling and bite site swelling were prominent clinical features. However haemorrhagic blisters, regional lymphadenopathy and coagulopathy were reported. Nephrotoxicity and neurotoxicity were notably absent., (Copyright © 2019. Published by Elsevier Ltd.)

The accumulation of beneficial biochemical compounds in different parts of pomegranate ( Punica granatum L.) fruit determines fruit quality and highly depends on environmental conditions. We investigated the effects of agro-climatic conditions on major biochemical compounds and on the expression of major anthocyanin biosynthetic genes in the peels and arils of a yellow-peeled and pink-ariled pomegranate cultivar in three agro-climatologically different locations in Sri Lanka. Drier and warmer climates promoted the accumulation of the measured biochemical compounds, i.e. total phenolic content (TPC), antioxidant capacity (AOX), and α, β, and total punicalagin, in both peels and arils compared to wetter and cooler climates. Pomegranate DFR, F3H, and ANS transcripts in both peels and arils showed higher relative expression in hotter and drier regions, compared to those grown in cooler and wetter conditions. Therefore, growing pomegranates in drier and warmer environments maximizes the production of beneficial biochemical compounds and associated gene expression in pomegranate fruit.

Immunotherapy has shown promising treatment effects for a variety of cancers. However, the immune treatment efficiency for solid tumors is limited owing to insufficient infiltration of immune cells into solid tumors. The conversion of tumor-supportive macrophages to tumor-suppressive macrophages, inducing the functional reversal of macrophages, is an effective method and contributes to a subsequent antitumor response. The current challenge in the field is the poor distribution and systemic side effects associated with the use of cytokines. As a solution to this issue, we designed and synthesized microenvironment-responsive nanoparticles (P) with IL-12 payload (IL-12⊂P1). These nanoparticles could promote the systemic administration and release of IL-12 in the tumor microenvironment, and the locally responsive property of IL-12⊂P1 could subsequently re-educate tumor-associated macrophages (TAMs). In particular, our results illustrated the great therapeutic effects derived from the functional conversion of macrophages. Our strategy was to design a microenvironment-responsive material for local macrophage modification to overcome the physiological barrier of solid tumors. The shifting of macrophage phenotypes via IL-12⊂P1 achieved immunomodulation in the microenvironment for cancer therapy, with negligible cytotoxicity. We expect that the functional regulation of TAMs by pH-responsive nanomaterials is a promising therapeutic approach for cancer immunotherapy., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Tomato Yellow Leaf Curl Virus (TYLCV) is an important plant virus on one of the economically most important vegetable crops; tomato (Lycopersicon esculentum Mill.). This had not been molecularly detected before, in Sri Lanka. TYLCV-GN-SL was isolated from apparently infected tomato plants using modified Cetyltrimethyl Ammonium Bromide (CTAB) method in Gannoruwa. Associated Begomoviruses were detected using Deng 541/Deng 540 and AV 494/AC 1048 primer pairs. TYLCV was detected for the first time in tomato in Sri Lanka using P1V/P4C, TYLCV specific primer pair. Nucleotide sequence of coat protein of isolated TYLCV-GN-SL proved that the Indian strain of ToLC virus was closely related to Tomato Leaf Curl Sri Lanka Virus (TLCV-SL: 97%) and Tomato leaf curl Geminivirus (TLCGV: 93%) through direct sequencing data. TLCV-SL was confirmed as TYLCV isolate. TYLCV was molecularly detected from major tomato growing districts like Badulla, Nuwara-Eliya, Kandy and Matale in Sri Lanka.

Introduction: Medical students undertake clinical procedures which carry a risk of sharps injuries exposing them to bloodborne infections., Objectives: To study the prevalence and correlates of sharps injuries among 4th-year medical students in the Faculty of Medicine, University of Colombo, Sri Lanka., Materials and Methods: The survey was conducted among 4th-year medical students to find out the incidence of injuries during high-risk procedures, associated factors and practice and perceptions regarding standard precautions. A self-administered questionnaire was administered to a batch of 197 4th-year medical students., Results: A total of 168 medical students responded. One or more injury was experienced by 95% (N = 159) of the students. The majority (89%) occurred during suturing; 23% during venipuncture and 14% while assisting in deliveries. Most of the incidents (49%) occurred during Obstetrics and Gynecology attachments. Recapping needles led to 8.6% of the injuries. Thirty-five percent of students believed they were inadequately protected. In this group, adequate protection was not available in 21% of the incidences and 24% thought protection was not needed. Following the injury, 47% completely ignored the event and only 5.7% followed the accepted post-exposure management. Only 34% of the students knew about post-exposure management at the time of the incident. Only 15% stated that their knowledge regarding prevention and management was adequate. The majority (97%) believed that curriculum should put more emphasis on improving the knowledge and practice regarding sharps injuries., Conclusions: The incidence of sharps injuries was high in this setting. Safer methods of suturing should be taught and practiced. The practice of standard precautions and post-injury management should be taught.

The clear cell odontogenic carcinoma (CCOC) is a rare, locally infiltrative neoplasm with a marked tendency for local recurrence and regional lymph node metastasis. The first description in 1985 included three cases of destructive jaw lesions. The entity was described as a clear cell odontogenic tumour in the previous WHO classification due to the fact that rarity of the lesion restricting pathologists to understand the spectrum of the degree of malignancy. These tumours have a peak incidence in the 5th-7th decades. CCOC tends to occur more frequently in the mandible, with a female predilection. The most striking histological feature is of large islands and strands of uniform cells with round or ovoid nuclei and clear cytoplasm. Presently we describe a case of clear cell odontogenic carcinoma in a 52-year-old female who presented with a bony-hard lump in the left body of the mandible. The patient is free of any recurrence after 2 years of follow-up.