Interspecific competition between larval stages of Aedes aegypti and Anopheles stephensi.

BACKGROUND & OBJECTIVES: Interspecific competition occurs between members of two or more different species and can often have an influence on mosquito populations. Both Aedes aegypti and Anopheles stepehensi are container breeding mosquitoes and co-exist which may result in larval competition. In this study, interspecific competition between the above two species has been monitored under the laboratory conditions. METHODS: Three sets of experiments were conducted with different stages of Ae. aegypti and An. stephensi larvae. First two experiments were set up with I/II instar and III/IV instar larvae of Ae. aegypti and An. stephensi respectively in the ratios of 20:20, 20:40 and 40:20 in plastic bowls. For third set of experiment 20 IV instar larvae of Ae. aegypti were put with equal number of I instar larvae of An. stephensi. RESULTS: In the presence of food, 12.5-15 % mortality was recorded in I/II stage larvae of Ae. aegypti while in An. stephensi mortality ranged from 21-55%. Pupation commenced from Day 6 onwards in Ae. aegypti while in An. stephensi it commenced from Day 11 onwards. In the absence of food, there was no pupation in both the species but Ae. aegypti survived up to longer duration (7.5-18.5 days with 50% mortality) in comparison to An. stephensi (2-7 days with 50% mortality). When younger stages of An. stephensi (I/II) were put together with older stages of Ae. aegypti (III/IV) in the presence of food, pupation was completed in 85% Ae. aegypti population while there was 100% mortality in An. stephensi population. INTERPRETATION & CONCLUSION: The better survival and development of Ae. aegypti than An. stephensi under the same conditions exhibits interspecies competition showing competitive advantage of Ae. aegypti over An. stephensi. Further research is required to have a thorough understanding of the interaction between these two container inhabiting mosquito species in the nature.

Efficacy of Vitamin C in Lowering Serum Uric Acid.

The objective of the study was to determine the efficacy of vitamin C in reducing serum uric acid (UA). This study was a double-blind placebo-controlled randomized trial conducted in the Department of Rheumatology, Bangabandhu Sheikh Mujib Medical University (BSMMU) Dhaka, Bangladesh from July 2007 and August 2008. Study participants were included from out patient department (OPD) of Rheumatology of BSMMU suffering from various Rheumatological problems other than gouty arthritis. All of the participants were non-smokers, non-alcoholics, and randomized to take either placebo or vitamin C (500 mg/day) for 12 weeks. A total of 98 subjects were enrolled in the study; 71 completed the trial, with 34 in the placebo group and 37 receiving vitamin C. Serum uric acid levels were not significantly reduced in the experimental group and they increased in the placebo group. In the vitamin C group, the mean change was -0.32mg/dl [95% confidence interval -0.73, 0.77], whereas in the placebo group, the mean change was +0.12mg/dl [95% confidence interval was -0.22, 0.47]. Subgroups were defined by sex, body mass index, and quartiles of baseline serum uric acid levels. In a subgroup analysis, vitamin C lowered serum uric acid significantly in those who had comparatively higher baseline uric acid levels. Although vitamin C did not lower serum uric acid significantly, participants with higher baseline serum uric acid levels experienced a significant uric acid lowering effect, but as the sample size was very small, it is difficult to draw any definitive conclusion.

1D self-assembly of chemisorbed thymine on Cu(110) driven by dispersion forces.

Adsorption of thymine on a defined Cu(110) surface was studied using reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD), and scanning tunnelling microscopy (STM). In addition, density functional theory (DFT) calculations were undertaken in order to further understand the energetics of adsorption and self-assembly. The combination of RAIRS, TPD, and DFT results indicates that an upright, three-point-bonded adsorption configuration is adopted by the deprotonated thymine at room temperature. DFT calculations show that the upright configuration adopted by individual molecules arises as a direct result of strong O-Cu and N-Cu bonds between the molecule and the surface. STM data reveal that this upright thymine motif self-assembles into 1D chains, which are surprisingly oriented along the open-packed [001] direction of the metal surface and orthogonal to the alignment of the functional groups that are normally implicated in H-bonding interactions. DFT modelling of this system reveals that the molecular organisation is actually driven by dispersion interactions, which cause a slight tilt of the molecule and provide the major driving force for assembly into dimers and 1D chains. The relative orientations and distances of neighbouring molecules are amenable for π-π stacking, suggesting that this is an important contributor in the self-assembly process.

Development, linguistic and clinimetric validation of the WOMAC VA3.01 Bangla for Bangladesh Index.

The aim of this study was to develop and to validate a Bengali version of the Western Ontario and McMaster Osteoarthritis (WOMAC) index in Bangladesh. The WOMAC was translated into the local language of Bangladesh (Bengali) and adapted in the local sociocultural context, following the standard guidelines by Beaton et al. Content validity of the preliminary Bengali version was assessed by using the index of content validity (ICV) and floor and ceiling effects. Patients were assessed at the Department of Rheumatology of Bangabandhu Sheikh Mujib Medical University and were diagnosed to have knee OA by American College of Rheumatology criteria and recruited according to the requirements of the validation study. Convergent and divergent validity were measured by comparing with Health Assessment Questionnaire (HAQ) and the Short Form-36 (SF-36), and internal consistency was assessed using Cronbach's alpha coefficient. The questionnaire was readministered to 40 patients within a week for assessing reliability by using intra-class correlation coefficient (ICC) and Spearman's rank correlation coefficient. In addition, factor analysis of Bengali WOMAC questionnaire was performed to examine the number of factors influencing a common set of items. A Bengali version was developed with changes in three items to suit local practices. The ICV of the content validity was 1 for all items. The Bengali WOMAC had similar construct validity when compared to the HAQ (ρ 0.74, n = 70) and SF-36 bodily pain and physical functioning. It had dissimilar construct validity to SF-36 mental health domain except WOMAC pain. Factor analysis revealed five factors with eigenvalues of more than 1.0. Cronbach's alpha and ICC exceeded 0.7 in all domains. In the test-retest reliability testing, Spearman's ρ for all items exceeded 0.4 (n = 40). This study has demonstrated that the Bengali version of WOMAC is a valid tool for assessing quality of life of patients with knee osteoarthritis in Bangladesh and is reliable.

Scleredema Diabeticorum - A Case Report.

Buschke Scleredema is a rare connective tissue disorder of unknown aetiology and characterized by thickening of the dermis. It resembles systemic sclerosis, eosinophilic fasciitis and cutaneous amyloidosis. Scleredema may be associated with a history of an antecedent febrile illness, diabetes mellitus, or blood dyscrasia. It may be classified into three clinical groups, each has a different history, course, and prognosis. Histology of skin is characterized by thickened dermis and increased spaces between large collagen bundles due to increased deposition of mucopolysaccharide in the dermis. Differential diagnosis can be made considering the typical clinical features and the histological peculiarity. No therapy is effective. In this communication we have presented a 54 year old man with scleredema successfully treated by PUVA and methotrexate. We reviewed associated diseases, clinical and histopathological characteristics, evolution and response to treatment.

Treatment of diffuse systemic sclerosis with hyperimmune caprine serum (AIMSPRO): a phase II double-blind placebo-controlled trial.

OBJECTIVE: The primary objective of the study was to explore safety and tolerability of hyperimmune caprine serum (AIMSPRO) in established diffuse cutaneous systemic sclerosis (SSc). Secondary objectives included assessment of potential efficacy and biological activity and exploration of candidate biomarkers. METHODS: This was a double-blind parallel group randomised placebo-controlled clinical trial. After informed consent 20 patients with established diffuse cutaneous SSc of greater than 3 years duration not receiving immunosuppressive therapy were randomised to receive either active (n=10) or placebo formulation (n=10) by subcutaneous twice weekly injection over 26 weeks. Clinical assessments were evaluated over 26 weeks. RESULTS: There were no safety concerns during this study. Frequency of adverse events was not different between active and placebo groups. Mean modified Rodnan Skin Score (mRSS) fell by 1.4±4.7 units with active treatment but increased by 2.1±6.4 units on placebo when baseline values were compared with 26 weeks and responder analysis showed clinically meaningful improvement in mRSS at 26 weeks in 5 (50%) of actively treated patients compared with 1 (10%) in the control group (p=0.062). PIIINP (µg/L) showed a comparatively larger increase in the treatment group compared with the placebo group, (p=0.0118). CONCLUSIONS: These results confirm tolerability and safety of this novel biological agent in established diffuse SSc. The value of a placebo treated control group in small clinical trials evaluating skin disease in SSc is confirmed. Potential improvement in mRSS and changes in PIIINP in cases receiving active therapy suggest that this intervention may be of clinical benefit and warrants further evaluation.

Laser-induced breakdown spectroscopy (LIBS) of animal fat (lard): Efficient sample preparation for onsite analysis and influence of sample temperature on the signal intensity and plasma parameters.

We report an efficient sample preparation method (freezing) for onsite fat and meat analysis via a specially designed thermoelectric cooling and temperature-controlling system. This investigation also focused on the effect of phase change on the sensitivity and reproducibility of LIBS emission signals and plasma parameters. The plasma emissions of animal fats (lard) were recorded when the sample was frozen (-2 °C), fluid (15 °C), and in a liquid state (37 °C) with a thermoelectric cooling system. At each temperature, the plasma emissions were acquired at laser pulse energy from 50 to 300 mJ and detector gate delay (DGD) from 0.5 to 5 µs. With increasing sample temperature, the DGD, where the optical emission intensity reached a maximum, decreased. At a laser pulse energy of 200 mJ and a sample temperature of -2 °C, the emission signals increased fourfold, the signal-to-noise ratio (SNR) improved tenfold, and the self-absorption in the emission lines decreased significantly. The repeatability of the emission signals and plasma parameters of frozen and liquid fat samples was determined using the relative standard deviation (RSD) of Se I (473.08 nm) and K I (766.48 nm) emission lines. The RSDs of the emission signals improved from 40 to 18 % and 37 to 16 %, whereas the shot-to-shot RSDs of the electron temperature and electron number density get improved from 11 to 6 % and 12 to 6.8 %, respectively.

Review of the bioenvironmental methods for malaria control with special reference to the use of larvivorous fishes and composite fish culture in central Gujarat, India.

Mosquito control with the use of insecticides is faced with the challenges of insecticide resistance in disease vectors, community refusal, their high cost, operational difficulties, and environmental concern. In view of this, integrated vector control strategies with the use of larvivorous fishes such as Guppy (Poecilia reticulata) and Gambusia (G. affinis) as biological control agents were used in controlling mosquito breeding in different types of breeding places such as intradomestic containers, various types of wells, rice-fields, pools, ponds and elsewhere in malaria prone rural areas of central Gujarat. Attempts were also made to demonstrate composite fish culture in unused abandoned village ponds by culturing Guppy along with the food fishes such as Rohu (Labeo rohita), Catla (Catla catla) and Mrigal (Cirrhinus mrigala). Income generated from these ponds through sale of fishes was utilized for mosquito control and village development. The technology was later adopted by the villagers themselves and food fish culture was practised in 23 ponds which generated an income of Rs 1,02,50,992 between 1985 and 2008. The number of villages increased from 13 to 23 in 2008 and there was also gradual increase of income from Rs 3,66,245 in 1985-90 to Rs 55,06,127 in 2002-08 block. It is concluded that larvivorous fishes can be useful tool in controlling mosquito breeding in certain situations and their use along with composite fish culture may also generate income to make the programme self-sustainable.

Cough in systemic lupus erythematosus.

This observational study was conducted in the lupus clinic of Department of Medicine, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from January 2007 to July 2007. Thirty-six consecutive SLE patients fulfilled American College of Rheumatology (ACR) diagnostic criteria and having cough for any duration was enrolled. Equal number of age and sex matched controls (The patient attending in the out patient department in the Medicine having cough without SLE) was taken after having informed consent. Severely disabled cases and cases unwilling to participate with a cough were excluded. Mean age of study population was 29.1±8.7 years and 29.8±9.9 years in controls. Duration of cough was less than 3 weeks in 17% of SLE patients and 8% of control group and was more than three weeks in 83% and 92% respectively. In SLE patient commonest causes of cough was bronchial asthma 47% and was 33% in controls. Post nasal drip syndrome was the next common causes and frequently due to sinusitis and allergic rhinitis. Its frequency was 14% and 16% in SLE and control groups respectively. Other causes were pneumonia (11%, 14%), Diffuse Parenchymal Disease lung (DPLD) (5.6% & 2.8%), and tuberculosis (5.6% & 8%) in SLE & control groups respectively. Gastro esophageal reflux disease (GERD) was 2.6% in SLE group but was not found in control group. Cough is common in SLE patients. Frequency distribution though similar to that of causes of cough in community but warns the possibility of serious underlying diseases in SLE cases and attentive evaluation.

Wegener's granulomatosis - a case report.

Wegener's granulomatosis is an uncommon multi-systemic disease characterized by necrotizing granulomatous inflammation of the upper and lower respiratory tracts and general focal necrotizing vasculitis (commonly known as Wegener's triad). The diagnosis of Wegener's granulomatosis is suggested from the clinical and laboratory findings and from the presence of circulating anti-neutrophil cytoplasmic antibodies (ANCA) although the absence of ANCA does not exclude the diagnosis. We described a case of 27-year-old man with pansinusitis, mild azotemia and initial respiratory tract symptoms such as foul smelling nasal discharge and epistaxis. Later he developed fever, poly-arthritis, abdominal pain and haematuria. There were multiple painful oral ulcers and skin showed multiple palpable purpuric rash. C-ANCA was positive. He was treated with IV methyl prednisolone 1gm daily for 3 days followed by oral prednisolone 1mg/kg body weight and oral cyclophosphamide. His condition improved dramatically and on follow up after 3 months he was reasonably well. In this report, we wanted to emphasize that Wegener's granulomatosis, although rare, should be considered in the above clinical scenario and treatment should be initiated as soon as possible.

Echocardiographic assessment of cardiac involvement in systemic lupus erythematosus patients.

This study was designed to assess cardiac abnormalities in patients with systemic lupus erythematosus (SLE) by echocardiography. It was an analytic type of cross sectional study, conducted in lupus clinic, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from July 2008 to June 2009. Fifty lupus patients, diagnosed on the basis of ACR criteria, without cardiovascular symptoms, were enrolled in the study and were evaluated by standard echocardiography with color Doppler. SLEDAI was applied for assessment of disease activity. Out of 50 patients 80% had abnormal echocardiographic findings. Pericardial thickening was found in 38% patients, pericardial effusion 20%, diastolic dysfunction 72%, hypokinesia of ventricular wall 8%, overall valvular abnormalities 20%, commonest being aortic regurgitation (12%), followed by mitral regurgitation (8%), and 6% had pulmonary hypertension. Males (100%) were more vulnerable to cardiac involvement than females (68.2%) and later age of disease onset (31-40 years) was associated with higher (87.5%) chance of echo abnormalities. The differences, however, were not statistically significant (p>0.05). There was significant relationship between disease duration and cardiac abnormalities (p<0.01). Active disease (80.08%) was associated with higher frequency of cardiac involvement than disease in remission (62.50%) but the result was not statistically significant (p=0.151). Cardiac abnormalities are very common in lupus patients even when clinically asymptomatic from cardiac aspect. Echocardiography is an excellent non-invasive tool for cardiac evaluation. These observations emphasize a need for further assessment of early intervention to reduce subsequent cardiac morbidity and mortality among the lupus patients.

Comparative efficacy of subcutaneous versus oral methotrexate in active rheumatoid arthritis.

This prospective study was conducted in rheumatology clinic under the department of medicine of Bangabandhu Sheikh Mujib Medical University from December 2004 to December 2005 to asses the efficacy, safety and compliance of subcutaneous methotrexate (MTX) in active rheumatoid arthritis (RA) patients. A total of 92 active rheumatoid arthritis patients according to American College of Rheumatology (ACR) criteria were recruited for the trial for six months. Among them 46 cases belonged to injectable MTX group and 46 cases belonged to oral MTX group. Mean±SD age of patients was 45.54±12.42 vs. 44.63±13.99 years in subcutaneous group and oral group respectively. In the subcutaneous group 41 were female and 5 male; in the oral group 34 were female and 12 male. Mean duration of the disease was 49.74 months in subcutaneous group and 49 months in oral group. RA test was positive in 35 cases in both groups whereas Rose Waaler test was positive in 19 patients in subcutaneous group and 14 patients in oral group. At 24 week, response rate of ACR 20 was significantly higher in subcutaneous MTX than oral MTX group (93% vs. 80%, p=0.02). Similarly ACR 50 response was significantly higher in subcutaneous MTX than in oral group (89% vs. 72%, p=0.03). ACR 70 response was not significantly higher in SCMTX group then oral group (11% vs. 9 %, p=0.72). Adverse effects were relatively less in subcutaneous MTX and most common side effects were nausea (37% vs. 63%), vomiting (11% vs. 30%), dyspepsia (29% vs. 48%), dizziness (4l% vs. 52%) and alopecia (72% vs. 85%). The results of the study demonstrated that subcutaneous MTX was significantly more effective than oral MTX at the same dosage in active Rheumatoid arthritis patients with no increase in side effects.

Bionomics and vectorial capacity of Anopheles annularis with special reference to India: a review.

Anopheles annularis is widely distributed mosquito species all over the country. An. annularis has been incriminated as a malaria vector in India, Sri Lanka, Bangladesh, Myanmar, Indonesia, Malaysia and China. In India, it has been reported to play an important role in malaria transmission as a secondary vector in certain parts of Assam, West Bengal and U.P. In Odisha and some neighbouring countries such as Sri Lanka, Nepal and Myanmar it has been recognised as a primary vector of malaria. This is a species complex of two sibling species A and B but the role of these sibling species in malaria transmission is not clearly known. An. annularis is resistant to DDT and dieldrin/HCH and susceptible to malathion and synthetic pyrethorides in most of the parts of India. In view of rapid change in ecological conditions, further studies are required on the bionomics of An. annularis and its role in malaria transmission in other parts of the country. Considering the importance of An. annularis as a malaria vector, the bionomics and its role in malaria transmission has been reviewed in this paper. In this communication, an attempt has been made to review its bionomics and its role as malaria vector. An. annularis is a competent vector of malaria, thus, due attention should be paid for its control under the vector control programmes specially in border states where it is playing a primary role in malaria transmission.

Current debates and emerging trends in the history of science in premodern Islamicate societies.

This roundtable brings together contributions from nine senior, mid-career and junior scholars who work on the history of science in pre-1800 Islamicate societies. The contributions reflect upon some of the challenges that have historically constrained the subfield, how they have sought to overcome them, and what they see as some of the more productive and fruitful turns the field has taken and/or should take in the future. A central trend in all contributions is how they seek to confront the combined weight of colonialism, Orientalism, and the teleological history of science that continues to haunt contemporary discussions in both academia and the general public with regards to science in pre-1800 Islamicate societies. Without diminishing the pioneering achievements of the generations of historians who have preceded us, and upon whose work we continue to rely, this combined weight has tended a) to marginalize the study of occult sciences in Islamicate societies; b) to emphasize investigations of content from an etic perspective of how we got to the present, which is primarily seen as how the scientific content is connected to the rise of modern science in Europe; and c) to concomitantly marginalize the study of science in post-1200 Islamicate societies, particularly those with little to no connection to the rise of "Western" science. The contributions build upon conversations that took place among participants in December 2019 at a workshop at New York University (NYU), Abu Dhabi Institute in New York City, funded by a grant from NYU Abu Dhabi.

Estimation of 10-Year Fracture Risk with and without Bone Mineral Density in Patients with Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is the most common inflammatory arthritis affecting 0.5-1.0% of the general population worldwide and although RA is properly considered a disease of the joints, it can cause a variety of extra-articular manifestations. This study was performed to find out any discrepancy in fracture risk estimates with and without bone mineral density (BMD) in rheumatoid arthritis (RA) patients. This observational cross-sectional study was carried out in the Department of Rheumatology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Bangladesh from July 2013 to July 2015. Total 65 consecutive patients with RA fulfilling ACR/EULAR criteria aged 40-90 year were recruited. Ten year fracture risk of these patients was evaluated by the FRAX score with and without BMD and differences were observed. FRAX score without BMD revealed that major fracture risk was low in 58(89.2%) patients, moderate in 7(10.8%) patients but re-estimation with BMD revealed that 55(84.6%) patients remained in low risk group, 8(12.3%) patients in moderate risk group and 2(3.1%) patients went to the high risk group. In case of hip fracture risk without BMD, risk was low in 58(89.2%) patients, high in 7(10.8%) patients; but with BMD, 50(76.9%) patients remained in low risk group but risk of 15(23.1%) patients became high. Almost all the high risk patients (93.3%) were ≥55 years of age. Increasing age, female sex, disease duration and use of steroid were positively correlated with increased FRAX score where as high BMI and high BMD were associated with low FRAX score. But in multivariate analysis it was found that only relation with age was at statistically significant level. Significant numbers of patients with rheumatoid arthritis have high risk of fracture especially hip fracture. The mean of FRAX score increased in both major & hip osteoporotic fracture risk after adding BMD. More than half of the patients above fifty five years or more had high risk of fracture. So, BMD should be done in patients aged more than fifty five.

Interactions outside the boundaries of the canonical binding groove of a PDZ domain influence ligand binding.

The postsynaptic density protein-95/discs large/zonula occludens-1 (PDZ) domain is a protein-protein interaction module with a shallow binding groove where protein ligands bind. However, interactions that are not part of this canonical binding groove are likely to modulate peptide binding. We have investigated such interactions beyond the binding groove for PDZ3 from PSD-95 and a peptide derived from the C-terminus of the natural ligand CRIPT. We found via nuclear magnetic resonance experiments that up to eight residues of the peptide ligand interact with the PDZ domain, showing that the interaction surface extends far outside of the binding groove as defined by the crystal structure. PDZ3 contains an extra structural element, a C-terminal helix (α3), which is known to affect affinity. Deletion of this helix resulted in the loss of several intermolecular nuclear Overhauser enhancements from peptide residues outside of the binding pocket, suggesting that α3 forms part of the extra binding surface in wild-type PDZ3. Site-directed mutagenesis, isothermal titration calorimetry, and fluorescence intensity experiments confirmed the importance of both α3 and the N-terminal part of the peptide for the affinity. Our data suggest a general mechanism in which different binding surfaces outside of the PDZ binding groove could provide sites for specific interactions.

Sequence-specific long range networks in PSD-95/discs large/ZO-1 (PDZ) domains tune their binding selectivity.

Protein-protein interactions mediated by modular protein domains are critical for cell scaffolding, differentiation, signaling, and ultimately, evolution. Given the vast number of ligands competing for binding to a limited number of domain families, it is often puzzling how specificity can be achieved. Selectivity may be modulated by intradomain allostery, whereby a remote residue is energetically connected to the functional binding site via side chain or backbone interactions. Whereas several energetic pathways, which could mediate intradomain allostery, have been predicted in modular protein domains, there is a paucity of experimental data to validate their existence and roles. Here, we have identified such functional energetic networks in one of the most common protein-protein interaction modules, the PDZ domain. We used double mutant cycles involving site-directed mutagenesis of both the PDZ domain and the peptide ligand, in conjunction with kinetics to capture the fine energetic details of the networks involved in peptide recognition. We performed the analysis on two homologous PDZ-ligand complexes and found that the energetically coupled residues differ for these two complexes. This result demonstrates that amino acid sequence rather than topology dictates the allosteric pathways. Furthermore, our data support a mechanism whereby the whole domain and not only the binding pocket is optimized for a specific ligand. Such cross-talk between binding sites and remote residues may be used to fine tune target selectivity.

Side-chain interactions form late and cooperatively in the binding reaction between disordered peptides and PDZ domains.

Intrinsically disordered proteins are very common and mediate numerous protein-protein and protein-DNA interactions. While it is clear that these interactions are instrumental for the life of the mammalian cell, there is a paucity of data regarding their molecular binding mechanisms. Here we have used short peptides as a model system for intrinsically disordered proteins. Linear free energy relationships based on rate and equilibrium constants for the binding of these peptides to ordered target proteins, PDZ domains, demonstrate that native side-chain interactions form mainly after the rate-limiting barrier for binding and in a cooperative fashion. This finding suggests that these disordered peptides first form a weak encounter complex with non-native interactions. The data do not support the recent notion that the affinities of intrinsically disordered proteins toward their targets are generally governed by their association rate constants. Instead, we observed the opposite for peptide-PDZ interactions, namely, that changes in K(d) correlate with changes in k(off).

Spectroscopic and crystallographic analysis of nephrite jade gemstone using laser induced breakdown spectroscopy, Raman spectroscopy, and X-ray diffraction.

The elemental composition, mineral phases, and crystalline structure of nephrite jade were investigated using calibration-free laser-induced breakdown spectroscopy (CF-LIBS), Raman spectroscopy, and X-ray diffraction (XRD). For compositional analysis, the laser-induced plasma was generated on the surface of nephrite jade. The plasma emissions were then acquired and analyzed, which revealed several elements in the sample, including Si, Mg, Ca, Li, Fe, Al, Na, K, and Ni. The plasma temperature was extracted from the Boltzmann plot before and after two-step self-absorption correction, and used in CF-LIBS calculations to get the elemental concentration. After self-absorption correction, the quantitative results obtained using CF-LIBS were found to be in close agreement with ICP-OES. The Raman spectrum of nephrite jade exhibits Si-O and M-OH stretching vibrations in the regions of 100 cm-1 to 1200 cm-1 and 3600 cm-1 to 3700 cm-1, respectively, whereas the XRD spectrum revealed the monoclinic crystalline phase of tremolite.