Harmonization service and global library of models to support country-driven global information on salt-affected soils

Global distribution of salt-affected soils (SAS) has remained at about 1 billion hectares in the literature over the years despite changes in climate, sea levels, and land use patterns which influence the distribution. Lack of periodic update of input soil data, data gaps, and inconsistency are part of the reasons for constant SAS distribution in the literature. This paper proposes harmonization as a suitable alternative for managing inconsistent data and minimizing data gaps. It developed a new harmonization service for supporting country-driven global SAS information update. The service contains a global library of harmonization models for harmonizing inconsistent soil data. It also contains models for identifying gaps in SAS database and for showing global distribution where harmonization of available data is needed. The service can be used by countries to develop national SAS information and update global SAS distribution. Its data availability index is useful in identifying countries without SAS data in the global database, which is a convenient way to identify countries to mobilize when updating global SAS information. Its application in 27 countries showed that the countries have more SAS data than they currently share with the global databases and that most of their data require SAS harmonization.

Effects of Riboflavin Collagen Crosslinker on Dentin Adhesive Bonding Efficiency: A Systematic Review and Meta-Analysis

The aim of this study was to evaluate published data regarding riboflavin (RF) as a cross-linker for improved adhesive bond strength to dentin and to analyze previous studies for optimal concentration of riboflavin range suitable for dentin bond. Saliva and distilled water were used as storage media and aging time was 24 h and 6 months. Results of meta-analysis were synthesized using a statistical method of inverse variance in random effects with a 95% Confidence Interval (CI). Cochrane review manager 5.4.1 was used to determine results of the meta-analysis. In total, 3172 articles were found from search databases "PubMed", "Scopus", and "Google Scholar". Six of the fifteen studies were eligible for meta-analysis. Micro tensile strength shows significant improvement with the addition of riboflavin (p < 0.05) compared to without the addition of riboflavin from with 95% CI. A significant difference has been found in micro tensile bond strength between use of the riboflavin cross-linker and without use of the riboflavin crosslinker in the dentin adhesive system. With a 95% confidence interval (CI), the I² for micro tensile strength was 89% with strong heterogeneity, Chi² = 44.76, df = 5 (p < 0.00001), and overall effect size is Z = 2.22 (p = 0.03) after immediate aging. Chiang et al. 2013 shows maximum mean differences which is 38.50 [17.93-59.07]. After 6 months of aging in distilled water or artificial saliva micro tensile bond strength has been increased with the addition of riboflavin (p < 0.05). It can be clearly seen that pooled effect and 95% CI did not cross the line of no effect. With a 95% confidence interval (CI), the I² for micro tensile strength was 96% with strong heterogeneity, Chi² = 117.56, df = 5 (p < 0.00001), and overall effect size is Z = 2.30 (p = 0.02). Subgroup analysis proved a similar effect of distilled water and artificial saliva as storage media on micro tensile bond strength after incorporating riboflavin as a collagen crosslinker. An artificial saliva aged forest plot also showed considerable heterogeneity with I² = 96%; Tau² = 257.32; Chi² = 94.37; df = 2 (p < 0.00001); test for overall effect, Z = 1.06 (p = 0.29). Riboflavin prior to or with bonding is recommended to improve the bonding of different adhesive systems.

Color variations during digital imaging of facial prostheses subjected to unfiltered ambient light and image calibration techniques within dental clinics: An in vitro analysis

Background

The study aimed to evaluate 1) the amount of color variations presents within clinical images of maxillofacial prosthetic silicone specimens when photographed under different clinically relevant ambient lighting conditions, and 2) whether white balance calibration (WBC) methods were able to mitigate variations in ambient lighting.

Methods

432 measurements were acquired from standardized images of the pigmented prosthetic silicone specimens within different ambient lighting conditions (i.e., 2 windowed and 2 windowless clinics) at noon with no light modifying apparatus. The specimens were photographed once without any white balance calibration (raw), then independently alongside an 18% neutral gray card and Macbeth color chart for calibration in a post-processing (PPWBC) software, and once after camera calibration (CWBC) using a gray card. The LAB color values were extracted from the images and color variations (ΔE) were calculated after referring to the corresponding spectrophotometric values as control.

Results

Images in windowless and windowed clinics exhibited highly significant differences (p < 0.001) with spectrophotometer (control). CWBC demonstrated no significant differences (p > 0.05) in LAB values across windowed clinics. PPWBC using Macbeth color chart produced no significant differences for a* values (p > 0.05) across all clinics while PPWBC by gray card showed no significant differences (p > 0.05) in LAB values when only similar clinics (either windowed or windowless) were compared.

Conclusion

Significant color variations were present for maxillofacial prosthetic specimens owing to natural ambient light. CWBC and PPWBC using color charts were more suitable for color correction across windowed clinics while CWBC and PPWBC using gray cards had better outcomes across windowless setups.

Impact of novel coronavirus pandemic on aquaculture and fisheries in developing countries and sustainable recovery plans: Case of Bangladesh

Like most sectors, the aquaculture and fisheries sector especially in developing countries like Bangladesh is believed to have been severely affected by this unique coronavirus (COVID-19) pandemic. To overcome the adverse impacts of COVID-19, the aquaculture and fisheries economy needs urgent recovery plans which this study focusses on using a mixed-method including online questionnaire surveys, face-to-face and telephonic interviews and focus group discussions during June - November 2020. This study reveals some positive impacts on ecosystem and fish stock (e.g., increase in fish stock) due to less disturbance of fishing activities, but that are not able to bring societal benefits as all the fisheries sub-sectors are affected differently by the pandemic. There are disrupted transportation systems and increased transportation costs (around 20 - 60% higher than normal), more input and maintenance costs and less demand for/and decreased market price of fish. There are also shortages of labourers and reduced patrolling to implement fishery regulations. Cancellation of orders by foreign buyers has seriously affected the shrimp and crab sub-sectors. The fisheries-dependent people's capital assets and activities have been mostly negatively affected resulting in a worsened livelihood. This study has suggested a set of immediate and long-term changes to policy and action plans to recover this sector and sub-sectors from the pandemic considering economic, social and environmental sustainability. The findings of this study may have important implications not only for Bangladesh but also for other fisheries dependent developing countries with similar impacts by the virus like in South Asia.

The loss of an eye due to occupational injury: Two case studies of ocular prosthetic rehabilitation

BACKGROUND

Two patients received ocular injuries from rusted metallic projectiles at their industrial workplaces. Said injuries resulted in the loss of their eyes by evisceration surgeries to prevent fatal infections.

CASE DESCRIPTION

The first case, a man in his twenties, received a stock conformer immediately after surgery and started prosthetic therapy within 2 months. The second case, a man in his forties, started prosthetic therapy after 10 years. Definitive custom ocular prostheses were fabricated and relined according to conventional protocol.

RESULTS

On issue of the prosthesis, there was adequate retention, aesthetics and stability to extra-ocular movements and treatment was considered successful for both cases. However, follow-ups showed noticeable prosthetic eye movements for case 1 which, to some extent mimicked the physiologic movement of its fellow natural eye. Case 1 adjusted to his prosthesis better while case 2 was still adjusting with little to no physiologic movement.

CONCLUSION

Prosthetic rehabilitation should be started as early as possible to obtain optimum rehabilitative results.

Paederus Dermatitis: A severe reaction to Charlie’s kiss

Paederus dermatitis is a very painful vesicular condition which is caused by the extremely potent toxin “Pederin” released from an insect calledPaederusfuscipes but commonly known as Charlie.A 26 years old woman presented with a sudden onset of neuralgia, arthralgia of left jaw, fever, nausea and fatigue with generalized pain radiating to the neck and lower jaw as well as itch-like sensation on their left arm associated with acute inflammation which began 24-48 hours prior. The patient refused to go to the hospital due to the current pandemic situation but instead updated us daily on her conditions with photographic changes of the arm until complete resolution of symptoms. This case report accounts for the daily sequential changes experienced by a patient after severe reaction to an exposure of pederin with photographs of the affected site. While the painful lesion and all systemic conditions resolved spontaneously over time, a scar was left to mark the unpleasant period. Bangladesh Journal of Medical Science Vol.20(2) 2021 p.459-462

Optimization of Prosthodontic Computer-Aided Designed Models: A Virtual Evaluation of Mesh Quality Reduction Using Open Source Software

PURPOSE

Mesh optimization reduces the texture quality of 3D models in order to reduce storage file size and computational load on a personal computer. This study aims to explore mesh optimization using open source (free) software in the context of prosthodontic application.

MATERIALS AND METHODS

An auricular prosthesis, a complete denture, and anterior and posterior crowns were constructed using conventional methods and laser scanned to create computerized 3D meshes. The meshes were optimized independently by four computer-aided design software (Meshmixer, Meshlab, Blender, and SculptGL) to 100%, 90%, 75%, 50%, and 25% levels of original file size. Upon optimization, the following parameters were virtually evaluated and compared; mesh vertices, file size, mesh surface area (SA), mesh volume (V), interpoint discrepancies (geometric similarity based on virtual point overlapping), and spatial similarity (volumetric similarity based on shape overlapping). The influence of software and optimization on surface area and volume of each prosthesis was evaluated independently using multiple linear regression.

RESULTS

There were clear observable differences in vertices, file size, surface area, and volume. The choice of software significantly influenced the overall virtual parameters of auricular prosthesis [SA: F(4,15) = 12.93, R² = 0.67, p < 0.001. V: F(4,15) = 9.33, R² = 0.64, p < 0.001] and complete denture [SA: F(4,15) = 10.81, R² = 0.67, p < 0.001. V: F(4,15) = 3.50, R² = 0.34, p = 0.030] across optimization levels. Interpoint discrepancies were however limited to <0.1mm and volumetric similarity was >97%.

CONCLUSION

Open-source mesh optimization of smaller dental prostheses in this study produced minimal loss of geometric and volumetric details. SculptGL models were most influenced by the amount of optimization performed.

Liming effects of poultry litter derived biochar on soil acidity amelioration and maize growth

Crop production in acid soils is facing enormous challenges due to low soil quality associated with an increase in the acidification rate and aluminum toxicity. Despite comprehensive prior work with biochar application on nutrient availability and crop productivity in acid soils, little information is available about the recommendation or standardization of biochar application rates that are more suitable for soil fertility improvement under different soil environments (physico-chemical properties) for maximizing the benefits of biochar applications and minimizing the potential environmental risk. Thus, the objective of this study was to investigate the effectiveness of poultry litter (PL) and poultry litter biochar (PLB) in ameliorating the fertility of acid soils through incubation and pot experiments. The soil was amended with different materials as follows; lime (1 g kg^-1), PL (5, 10 and 15 g kg^-1) and PLB (5, 10 and 15 g kg^-1) along with control (non-amended). A pot experiment was also conducted using similar treatments to observe the responses of maize crop to the different amendments. The results indicated an increase in the pH and a decrease in exchangeable acidity in lime, PL and PLB amended soils. Lower soil pH, base cations and soil available phosphorus (P), and higher exchangeable acidity were found in control than the amended soils. Compared to PL and lime, PLB achieved greater increase rate in soil pH and reduction rate in soil exchangeable acidity with increased soil exchangeable base cations. An increase in soil available calcium (Ca) was observed in the lime treatment, while in PL and PLB treatments, there was an increase in soil available Ca, magnesium (Mg), potassium (K) and P. Application of the amendments increased availability of nitrogen (N), P, K, Ca and Mg relative to the control for maize in the pot experiment. When PL and PLB amendments were compared, it was found that the PLB was the best choice for the amelioration of acid soils as well as nutrient uptake by maize plants. It is suggested that application of PLB at the rate of 15 g kg^-1 is suitable for maize growth in acid soils.

Evaluation of the Differences Between Conventional and Digitally Developed Models Used for Prosthetic Rehabilitation in a Case of Untreated Palatal Cleft

OBJECTIVE

The virtual cone beam computed tomography-derived 3-dimensional model was compared with the scanned conventional model used in the fabrication of a palatal obturator for a patient with a large palatal defect.

DESIGN

A digitally derived 3-dimensional maxillary model incorporating the palatal defect was generated from the patient's existing cone beam computerized tomography data and compared with the scanned cast from the conventional impression for linear dimensions, area, and volume. The digitally derived cast was 3-dimensionally printed and the obturator fabricated using traditional techniques. Similarly, an obturator was fabricated from the conventional cast and the fit of both final obturator bulbs were compared in vivo.

RESULTS

The digitally derived model produced more accurate volumes and surface areas within the defect. The defect margins and peripheries were overestimated which was reflected clinically.

CONCLUSION

The digitally derived model provided advantages in the fabrication of the palatal obturator; however, further clinical research is required to refine consistency.

The Influence of Filler Particles on the Mechanical Properties of Maxillofacial Prosthetic Silicone Elastomers: A Systematic Review and Meta-Analysis

Although numerous studies have demonstrated the benefits of incorporating filler particles into maxillofacial silicone elastomer (MFPSE), a review of the types, concentrations and effectiveness of the particles themselves was lacking. The purpose of this systematic review and meta-analysis was to review the effect of different types of filler particles on the mechanical properties of MFPSE. The properties in question were (1) tensile strength, (2) tear strength, (3) hardness, and (4) elongation at break. The findings of this study can assist operators, technicians and clinicians in making relevant decisions regarding which type of fillers to incorporate based on their needs. The systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 26 original articles from 1970 to 2019 were selected from the databases, based on predefined eligibility criteria by two reviewers. The meta-analyses of nine papers were carried out by extracting data from the systematic review based on scoring criteria and processed using Cochrane Review Manager 5.3. Overall, there were significant differences favoring filler particles when incorporated into MFPSE. Nano fillers (69.23% of all studies) demonstrated superior comparative outcomes for tensile strength (P < 0.0001), tear strength (P < 0.00001), hardness (P < 0.00001) and elongation at break (P < 0.00001) when compared to micro fillers (30.76% of all studies). Micro fillers demonstrated inconsistent outcomes in mechanical properties, and meta-analysis of elongation at break argued against (P < 0.01) their use. Current findings suggest that 1.5% ZrSiO4, 3% SiO2, 1.5% Y2O3, 2-6% TiO2, 2-2.5% ZnO, 2-2.5% CeO2, 0.5% TiSiO4 and 1% Ag-Zn Zeolite can be used to reinforce MFPSE, and help the materials better withstand mechanical degradation.

Sustaining an obturator prosthesis with zygomatic suspension wires in a case of subtotal maxillectomy and insuffient ridge supported retention: A case report

Purpose: For making denture in maxillectomy cases is very difficult and challenging to get the retention tomake the denture stable in its position during functioning. This case report describes a clinical condition inwhich patient was treated with a maxillary obturator with zygomatic suspension wiring due to insufficientretention in the palate. Materials and Methods: A 63-year-old patient had gone to a subtotal maxillectomybecause following myofibroblastic sarcoma andwas issued with bilateral circum-zygomatic wiring hooksimmediately after surgery. The patient had less than a third of their alveolar ridge remaining and did notprovide sufficient retention on its own. The wires were used for the retention because natural retentioncould not get due to inadequate maxillary ridge. While the denture was being fabricated, a temporaryfeeding plate was provisioned to the patient. Counter hooks were implemented on the definitive upperdenture, posterior to molars, to attach to the zygomatic suspension hook. Final upper denture was furtherreinforced with denture adhesive on it. A lower denture was also fabricated for the said case followingconventional protocols of jaw relation determination. Results: The obturator provided with adequate sealand leak proof phonetics. The zygomatic wiring coupled with denture adhesive were sufficient to provideadequate retention. Conclusion: Zygomatic suspension wires coupled with counter hooked obturatorprosthesis provide rehabilitation of patients with palatal defects with inadequate maxillary arch forretention.However long-term repeated use of such wires might expose the patient to secondary infectionsand should be kept in consideration Clinical Significance: Circum-zygomatic suspension wiring providesufficient retention to sustain the upper obturator prosthesis in place. However, the retention was stillinadequate, so denture adhesives were used to make it more stable. Bangladesh Journal of Medical Science Vol.19(3) 2020 p.582-585

Vermicomposting of citronella bagasse and paper mill sludge mixture employing Eisenia fetida

The vermicomposting potential of Eisenia fetida on citronella bagasse and paper mill sludge mixture was studied. The experiment was carried out in pots by taking a mixture of citronella bagasse and paper mill sludge in 3:2 ratios. The physico-chemical properties such as pH, conductivity, total organic carbon, nitrogen, phosphorus, potassium, calcium, trace elements and heavy metals were studied in the end products. The ash content, humification index, C/N ratio and scanning electron microscopic analysis were done to understand the maturity of the vermicompost. Results revealed that bioconversion of citronella bagasse and paper mill sludge mixture is accompanied with reduction of C/N ratio and humification index; enhancement of nutrients profile, nitrogen fixing, phosphate and potassium solubilizing bacterial population. SEM analysis showed that there was more disintegration in vermicompost samples than the initial raw materials and compost. Further, earthworm population and biomass has significantly increased by the end of the experimental trials.

All-optical detection of interfacial spin transparency from spin pumping in β-Ta/CoFeB thin films

Generation and utilization of pure spin current have revolutionized energy-efficient spintronic devices. Spin pumping effect generates pure spin current, and for its increased efficiency, spin-mixing conductance and interfacial spin transparency are imperative. The plethora of reports available on generation of spin current with giant magnitude overlook the interfacial spin transparency. Here, we investigate spin pumping in β-Ta/CoFeB thin films by an all-optical time-resolved magneto-optical Kerr effect technique. From variation of Gilbert damping with Ta and CoFeB thicknesses, we extract the spin diffusion length of β-Ta and spin-mixing conductances. Consequently, interfacial spin transparency is derived as 0.50 ± 0.03 from the spin Hall magnetoresistance model for the β-Ta/CoFeB interface. Furthermore, invariance of Gilbert damping with Cu spacer layer thickness inserted between β-Ta and CoFeB layers confirms the absence of other interface effects including spin memory loss. This demonstrates a reliable and noninvasive way to determine interfacial spin transparency and signifies its role in generation of pure spin current by spin pumping effect.

An Innovative Root Inoculation Method to Study Ralstonia solanacearum Pathogenicity in Tomato Seedlings

In this study, we report Ralstonia solanacearum pathogenicity in the early stages of tomato seedlings by an innovative root inoculation method. Pathogenicity assays were performed under gnotobiotic conditions in microfuge tubes by employing only 6- to 7-day-old tomato seedlings for root inoculation. Tomato seedlings inoculated by this method exhibited the wilted symptom within 48 h and the virulence assay can be completed in 2 weeks. Colonization of the wilted seedlings by R. solanacearum was confirmed by using gus staining as well as fluorescence microscopy. Using this method, mutants in different virulence genes such as hrpB, phcA, and pilT could be clearly distinguished from wild-type R. solanacearum. The method described here is economic in terms of space, labor, and cost as well as the required quantity of bacterial inoculum. Thus, the newly developed assay is an easy and useful approach for investigating virulence functions of the pathogen at the seedling stage of hosts, and infection under these conditions appears to require pathogenicity mechanisms used by the pathogen for infection of adult plants.

Multilevel programming in Cu/NiO y /NiO x /Pt unipolar resistive switching devices

The application of a NiO y /NiO x bilayer in resistive switching (RS) devices with x > y was studied for its ability to achieve reliable multilevel cell (MLC) characteristics. A sharp change in resistance brought about by sweeping the voltage, along with an improved on/off ratio (>10(3)) and endurance (10(4)) were achieved in the bilayer structure as compared to the single NiO x layer devices. Moreover, it was found that nonvolatile and stable resistance levels, especially the multiple low-resistance states of Cu/NiO y /NiO x /Pt memory devices, could be controlled by varying the compliance current. All the multilevel resistance states of the Cu/NiO y /NiO x /Pt bilayer devices were stable for up to 500 consecutive dc switching cycles, as compared to the Cu/NiO x /Pt single layer devices. The temperature-dependent variation of the high and low resistance states of both the bilayer and single layer devices was further investigated to elucidate the charge conduction mechanism. Finally, based on a detailed analysis of the experimental results, comparisons of the possible models for RS in bilayer and single layer memory devices have also been discussed.

Epistatic interaction of genetic depression risk variants in the human subgenual cingulate cortex during memory encoding

Recent genome-wide association studies have pointed to single-nucleotide polymorphisms (SNPs) in genes encoding the neuronal calcium channel CaV1.2 (CACNA1C; rs1006737) and the presynaptic active zone protein Piccolo (PCLO; rs2522833) as risk factors for affective disorders, particularly major depression. Previous neuroimaging studies of depression-related endophenotypes have highlighted the role of the subgenual cingulate cortex (CG25) in negative mood and depressive psychopathology. Here, we aimed to assess how recently associated PCLO and CACNA1C depression risk alleles jointly affect memory-related CG25 activity as an intermediate phenotype in clinically healthy humans. To investigate the combined effects of rs1006737 and rs2522833 on the CG25 response, we conducted three functional magnetic resonance imaging studies of episodic memory formation in three independent cohorts (N=79, 300, 113). An epistatic interaction of PCLO and CACNA1C risk alleles in CG25 during memory encoding was observed in all groups, with carriers of no risk allele and of both risk alleles showing higher CG25 activation during encoding when compared with carriers of only one risk allele. Moreover, PCLO risk allele carriers showed lower memory performance and reduced encoding-related hippocampal activation. In summary, our results point to region-specific epistatic effects of PCLO and CACNA1C risk variants in CG25, potentially related to episodic memory. Our data further suggest that genetic risk factors on the SNP level do not necessarily have additive effects but may show complex interactions. Such epistatic interactions might contribute to the 'missing heritability' of complex phenotypes.

Magnetic vortex based transistor operations

Transistors constitute the backbone of modern day electronics. Since their advent, researchers have been seeking ways to make smaller and more efficient transistors. Here, we demonstrate a sustained amplification of magnetic vortex core gyration in coupled two and three vortices by controlling their relative core polarities. This amplification is mediated by a cascade of antivortex solitons travelling through the dynamic stray field. We further demonstrated that the amplification can be controlled by switching the polarity of the middle vortex in a three vortex sequence and the gain can be controlled by the input signal amplitude. An attempt to show fan-out operation yielded gain for one of the symmetrically placed branches which can be reversed by switching the core polarity of all the vortices in the network. The above observations promote the magnetic vortices as suitable candidates to work as stable bipolar junction transistors (BJT).

A case of ileo-caecal Crohn's disease presenting as acute intestinal obstruction

We report a case of 42 year old man who presented with one month history of weight loss, gradual abdominal distension and constipation. X-ray of the abdomen showed features of small gut obstruction. A tight stricture at the ileoceacal junction was found to be the cause of obstruction on laparotomy. Distal ileum was found to be severely inflammed with enlarged regional lymph nodes. Right hemicolectomy with resection of distal ileum was done. Histology revealed non caseating granuloma of Chroh's disease. Crohn's disease is relatively rare in Bangladesh. Recent data suggests rising incidence of Crohn's disease (CD) in the Indian sub-continent.

Hazardous alcohol use in rural southern India: nature, prevalence and risk factors

BACKGROUND

There is a dearth of data on the hazardous use of alcohol in rural India.

METHODS

We examined the nature, prevalence and factors associated with hazardous use of alcohol among men in a rural community in southern India. We used stratified sampling to select subjects from the Kaniyambadi block and employed 'AUDIT', a standard instrument, to assess the use of alcohol.

RESULTS

The prevalence of life-time use, use in the past year and hazardous use of alcohol was 46.7%, 34.8% and 14.2%, respectively. Using Indian made foreign liquor (OR 20.51; 95% CI 8.81-47.75) and living in a village which brewed illicit alcohol (OR 2.82; 95% CI 1.39-5.72) were risk factors for hazardous use while education (OR 0.39; 95% CI 0.21-0.72) was protective. These factors remained significantly associated with hazardous use after adjusting for age and education using logistic regression.

CONCLUSION

The relationship between the availability of illicit and commercial alcohol and its hazardous use suggests the need for an alcohol policy which takes into account health and economic issues and also implements the law to prevent the negative impact of problem drinking.

Standard Setting in Student Assessment: Is a Defensible Method Yet to Come?

Introduction: Setting, maintaining and re-evaluation of assessment standard periodically are important issues in medical education. The cut-off scores are often “pulled from the air” or set to an arbitrary percentage. A large number of methods/procedures used to set standard or cut score are described in literature. There is a high degree of uncertainty in performance standard set by using these methods. Standards set using the existing methods reflect the subjective judgment of the standard setters. This review is not to describe the existing standard setting methods/procedures but to narrate the validity, reliability, feasibility and legal issues relating to standard setting. Materials and Methods: This review is on some of the issues in standard setting based on the published articles of educational assessment researchers. Results: Standard or cut-off score should be to determine whether the examinee attained the requirement to be certified competent. There is no perfect method to determine cut score on a test and none is agreed upon as the best method. Setting standard is not an exact science. Legitimacy of the standard is supported when performance standard is linked to the requirement of practice. Test-curriculum alignment and content validity are important for most educational test validity arguments. Conclusion: Representative percentage of must-know learning objectives in the curriculum may be the basis of test items and pass/fail marks. Practice analysis may help in identifying the must-know areas of curriculum. Cut score set by this procedure may give the credibility, validity, defensibility and comparability of the standard. Constructing the test items by subject experts and vetted by multi-disciplinary faculty members may ensure the reliability of the test as well as the standard. Key words: Difficulty and discriminating indices, Judges and judgment, Legal issues, Practicability, Reliability, Validity

Standard setting in student assessment: is a defensible method yet to come?

INTRODUCTION

Setting, maintaining and re-evaluation of assessment standard periodically are important issues in medical education. The cut-off scores are often "pulled from the air" or set to an arbitrary percentage. A large number of methods/procedures used to set standard or cut score are described in literature. There is a high degree of uncertainty in performance standard set by using these methods. Standards set using the existing methods reflect the subjective judgment of the standard setters. This review is not to describe the existing standard setting methods/procedures but to narrate the validity, reliability, feasibility and legal issues relating to standard setting.

MATERIALS AND METHODS

This review is on some of the issues in standard setting based on the published articles of educational assessment researchers.

RESULTS

Standard or cut-off score should be to determine whether the examinee attained the requirement to be certified competent. There is no perfect method to determine cut score on a test and none is agreed upon as the best method. Setting standard is not an exact science. Legitimacy of the standard is supported when performance standard is linked to the requirement of practice. Test-curriculum alignment and content validity are important for most educational test validity arguments.

CONCLUSION

Representative percentage of must-know learning objectives in the curriculum may be the basis of test items and pass/fail marks. Practice analysis may help in identifying the must-know areas of curriculum. Cut score set by this procedure may give the credibility, validity, defensibility and comparability of the standard. Constructing the test items by subject experts and vetted by multi-disciplinary faculty members may ensure the reliability of the test as well as the standard.

Prevalence of asymptomatic bacteriuria and its consequences in pregnancy in a rural community of Bangladesh

This was a cross-sectional followed by cohort type of study conducted among the pregnant mothers of second trimester in the rural areas of Rajshahi district. Initially 1800 pregnant mothers ofsecond trimester were selected from 18 unions applying 2-stage random sampling. A total of 216 pregnant mothers with asymptomatic bacteriuria were paired among the rest of the healthy pregnant mothers (without bacteriuria) on the basis of age, gravida and economic status for cohort study to relate asymptomatic bacteriuria with the incidence of symptomatic bacteriuria, hypertensive disorders in pregnancy (HDP) and pre-term delivery. The matched paired pregnant mothers werefollowed monthly interval up to delivery. The prevalence of asymptomatic bacteriuria was 12% among the pregnant mothers in rural Rajshahi. E. Coli was the commonest causative agent of both asymptomatic and symptomatic bacteriuria. The results of this study suggest that asymptomatic bacteriuria were more prone to develop symptomatic bacteriuria, hypertensive disorders in pregnancy and pre-term delivery than that of the healthy mothers (without bacteriuria). Screening of bacteriuria in pregnancy and proper treatment must be considered as an essential part of antenatal care in this rural community.

Microphotonic control of single molecule fluorescence correlation spectroscopy using planar optofluidics

We demonstrate the implementation of fluorescence correlation spectroscopy (FCS) on a chip. Full planar integration is achieved by lithographic definition of sub-picoliter excitation volumes using intersecting solid and liquid-core optical waveguides. Concentration dependent measurements on dye molecules with single molecule resolution are demonstrated. Theoretical modeling of the FCS autocorrelation function in microstructured geometries shows that the FCS behavior can be controlled over a wide range by tailoring the micro-photonic environment. The ability to perform correlation spectroscopy using silicon photonics without the need for free-space microscopy permits implementation of numerous diagnostic applications on compact planar optofluidic devices.

Critiques on the Objective Structured Clinical Examination

INTRODUCTION

The main aim of medical education is to foster the development of clinical competence in students at all levels. Differences in experiences, methods of instruction and ambiguous forms of assessment are obstacles to attaining this goal. Dissatisfaction with the conventional methods of clinical assessment on the part of teachers and students led assessors to search for appropriate alternatives and in 1975, Harden and his colleagues introduced the objective structured clinical examination (OSCE). It is nearly impossible to have a test that satisfies all the criteria of a good test. Sometimes, a compromise has to be made between the available resources (in terms of man, money and time), and the method and quality of assessment (in terms of reliability, validity, objectivity and practicability).

METHODS

This critique on the OSCE is based on the published findings of researchers from its inception in 1975 to 2004.

RESULTS

The reliability, validity, objectivity and practicability or feasibility of this examination are based on the number of stations, construction of stations, method of scoring (checklists and/ or global scoring) and number of students assessed. For a comprehensive assessment of clinical competence, other methods should be used in conjunction with the OSCE.

CONCLUSION

The OSCE can be a reasonably reliable, valid and objective method of assessment, but its main drawback is that it is resource-intensive.

Case report: Spinal cord herniation into a mediastinal neurenteric cyst: CT and MRI findings

Split notochord syndrome is a spectrum of congenital spinal malformations that develops due to an adhesion between endoderm and ectoderm causing the "splitting" of notochord. Neurenteric cyst is one of the components of split notochord syndrome. We report CT and MRI findings of an unusual case with thoracal spinal cord herniation into a mediastinal neurenteric cyst.

Atrial natriuretic peptide inhibits mineralocorticoid receptor function in rat colonic surface cells

Atrial natriuretic peptide (ANP) inhibits and aldosterone (ALDO) stimulates Na conductive transport. Therefore, the effects of ANP and its second messenger cGMP on mineralocorticoid receptor (MR) function in rat colon surface and crypt cells were examined. 100 nM 8-Br-cGMP decreased surface [3H]ALDO binding by 42 +/- 4% but increased crypt [3HvALDO binding by 52+/-16%. ANP decreased surface [3H]ALDO binding by approximately 50% after a 2.5-h lag period but had no effect on crypt ALDO binding. ANP and cGMP rapidly (< 15 min) inhibited surface cell ALDO-induced MR nuclear translocation but did not affect crypt MR nuclear translocation. Inhibition of cGMP-dependent protein kinase with KT5823 blocked the inhibitory effects of ANP and 8-Br-cGMP on surface cell ALDO binding and MR nuclear translocation. In crypt, KT5823 increased baseline [3H]ALDO binding but did not inhibit the stimulatory effect of exogenous cGMP. DEAE-cellulose chromatography and gel mobility shift assay showed that ANP did not inhibit surface MR activation. ANP inhibited ALDO stimulated short circuit current in distal colon. These data demonstrate cell-specific regulation of MR function. In surface cells, ANP rapidly inhibits MR nuclear translocation and ALDO-induced short circuit current. ANP inhibition of MR function may be an additional mechanism of ANP antagonism of Na reabsorption.

A baseline survey on use of drugs at the primary health care level in Bangladesh

The drug use pattern and the quality of care were assessed in 80 public sector facilities throughout rural Bangladesh. A total of 40 thana health complexes and 40 union subcentres, the lowest level in primary health care facilities, were selected at random. A total of 2880 prescriptions, consultations, and drug-dispensing practices were studied, and the availability and use of essential drugs and of the essential drugs list were recorded. The average consulting time (54 seconds), the proportion of adequate examinations (37%), and prescription of drugs according to standard treatment guidelines (41%) were unsatisfactory. The mean number of drugs prescribed per patient was 1.44; 25% were treated with antibiotics, and 17% with metronidazole, irrespective of the diagnoses. The availability of drugs (54%) and the presence of an essential drugs list (16%) in the health facilities were low. However, 78% of the drugs were prescribed by their generic names, 85% complied with the essential drugs list, and 81% were dispensed according to prescription. The average dispensing time (23 seconds) and the proportion of patients who correctly understood the dosage (55%) were poor.

Renal sarcoidosis coexisting with hypernephroma

Hypernephroma arising in a kidney infiltrated by sarcoidosis is unusual. To date, there has been no such case reported. The hypernephroma was suspected by the presence of localized parenchymal calcifications and confirmed by selective renal angiography.