Exact-diagonalization method for soft-core bosons in optical lattices using hierarchical wavefunctions

In this work, we describe a new technique for numerical exact-diagonalization. The method is particularly suitable for cold bosonic atoms in optical lattices, in which multiple atoms can occupy a lattice site. We describe the use of the method for Bose-Hubbard model as an example, however, the method is general and can be applied to other lattice models. The proposed numerical technique focuses in detail on how to construct the basis states as a hierarchy of wavefunctions. Starting from single-site Fock states we construct the basis set in terms of row-states and cluster-states. This simplifies the application of constraints and calculation of the Hamiltonian matrix. Each step of the method can be parallelized to accelerate the computation. In addition, we have illustrated the computation of the spatial bipartite entanglement entropy in the correlated $\nu =1/2$ fractional quantum Hall state.Comment: 11 pages, 6 figures, Comments are most welcom

Fractional quantum Hall effect in optical lattices

In this research, we study the bosonic fractional quantum Hall (FQH) states in a system of ultracold bosons in a two-dimensional optical lattice in the presence of a synthetic magnetic field, described by the bosonic Harper–Hofstadter Hamiltonian. We use the cluster Gutzwiller mean-field and exact diagonalization techniques in our work. We obtain incompressible states as ground states at various filling factors similar to those of the FQH states. We focus in particular on the ν = 1/2 FQH state, and it is characterized by the two-point correlation function and the many-body Chern number. We further investigate the effect of dipolar interaction on the ν = 1/2 FQH state. We find that the dipolar interaction stabilizes the FQH state against the competing superfluid state

Interaction of human pancreatic ribonuclease with human ribonuclease inhibitor

Mammalian ribonucleases interact very strongly with the intracellular ribonuclease inhibitor (RI). Eukaryotic cells exposed to mammalian ribonucleases are protected from their cytotoxic action by the intracellular inhibition of ribonucleases by RI. Human pancreatic ribonuclease (HPR) is structurally and functionally very similar to bovine RNase A and interacts with human RI with a high affinity. In the current study, we have investigated the involvement of Lys-7, Gln-11, Asn-71, Asn-88, Gly-89, Ser-90, and Glu-111 in HPR in its interaction with human ribonuclease inhibitor. These contact residues were mutated either individually or in combination to generate mutants K7A, Q11A, N71A, E111A, N88R, G89R, S90R, K7A/E111A, Q11A/E111A, N71A/E111A, K7A/N71A/E111A, Q11A/N71A/E111A, and K7A/Q11A/N71A/E111A. Out of these, eight mutants, K7A, Q11A, N71A, S90R, E111A, Q11A/E111A, N71A/E111A, and K7A/N71A/E111A, showed an ability to evade RI more than the wild type HPR, with the triple mutant K7A/N71A/E111A having the maximum RI resistance. As a result, these variants exhibited higher cytotoxic activity than wild type HPR. The mutation of Gly-89 in HPR produced no change in the sensitivity of HPR for RI, whereas it has been reported that mutating the equivalent residue Gly-88 in RNase A yielded a variant with increased RI resistance and cytotoxicity. Hence, despite its considerable homology with RNase A, HPR shows differences in its interaction with RI. We demonstrate that interaction between human pancreatic ribonuclease and RI can be disrupted by mutating residues that are involved in HPR-RI binding. The inhibitor-resistant cytotoxic HPR mutants should be useful in developing therapeutic molecules

The Yeast Hsp70 Cochaperone Ydj1 Regulates Functional Distinction of Ssa Hsp70s in the Hsp90 Chaperoning Pathway

Heat-shock protein (Hsp) 90 assists in the folding of diverse sets of client proteins including kinases and growth hormone receptors. Hsp70 plays a major role in many Hsp90 functions by interacting and modulating conformation of its substrates before being transferred to Hsp90s for final maturation. Each eukaryote contains multiple members of the Hsp70 family. However, the role of different Hsp70 isoforms in Hsp90 chaperoning actions remains unknown. Using v-Src as an Hsp90 substrate, we examined the role of each of the four yeast cytosolic Ssa Hsp70s in regulating Hsp90 functions. We show that the strain expressing stress-inducible Ssa3 or Ssa4, and the not constitutively expressed Ssa1 or Ssa2, as the sole Ssa Hsp70 isoform reduces v-Src-mediated growth defects. The study shows that although different Hsp70 isoforms interact similarly with Hsp90s, v-Src maturation is less efficient in strains expressing Ssa4 as the sole Hsp70. We further show that the functional distinction between Ssa2 and Ssa4 is regulated by its C-terminal domain. Further studies reveal that Ydj1, which is known to assist substrate transfer to Hsp70s, interacts relatively weakly with Ssa4 compared with Ssa2, which could be the basis for poor maturation of the Hsp90 client in cells expressing stress-inducible Ssa4 as the sole Ssa Hsp70. The study thus reveals a novel role of Ydj1 in determining the functional distinction among Hsp70 isoforms with respect to the Hsp90 chaperoning action

Utjecaj pandemije COVID-19 i karantene na anksioznost u starijoj populaciji: presječna studija

Background: The coronavirus pandemic is an epidemiological and psychological crisis. The elderly population is considered to be high risk for potential complications arising from the COVID-19 pandemic, and this fact can also potentially lead to anxiety symptoms amongst the elderly. Therefore, a study was conducted to assess the anxiety symptoms in elderly living in few major cities of Rajasthan state in India. Methods: The study was conducted from April 2020 to May 2020 using an online questionnaire which measured the levels of anxiety amongst the elderly population (age ≥ 65 years) living in the community via the GAD-7 (General Anxiety Disorder-7) scale. Responses were received from 162 participants. Data were analyzed using the Chi-square test and logistic regression. The level of statistical significance was kept at p value < 0.05. Results: Around 69.14% of the participants belonged to the age group of 65 -74 years; 61.72% of whom were male. Moreover, up to 82.72% of the participants were suffering from one or more chronic medical illnesses. Based on the GAD-7 scores, 30.25%, 12.35%, and 6.17% of the respondents were suffering from mild, moderate, and severe forms of anxiety, respectively. After applying a ≥ 5 score as a cut off score for the GAD-7 scale, 48.77% of the elderly participants were experiencing anxiety symptoms indicating further assessment. In those respondents with anxiety symptoms, significant association was observed with age (p = 0.00), sex (p = 0.04), and the zone of residence (p = 0.00). On the other hand, no significant association was observed with the presence of chronic medical illness such as Diabetes, Hypertension, COPD, etc. with anxiety symptoms (p = 0.77). Conclusion: This study has revealed a high prevalence of anxiety symptoms among the elderly population during the COVID-19 pandemic lock down. We recommend that a pre-planned strategy should be prepared for early identification of vulnerable elderly in the community who are at a greater risk of suffering from anxiety disorder under this stressful period.Pozadina: Pandemija koronavirusa epidemiološka je i psihološka kriza. Starija populacija smatra se visoko rizičnom za potencijalne komplikacije koje proizlaze iz pandemije COVID-19, što također može dovesti do simptoma anksioznosti kod starijih osoba. Stoga je provedeno istraživanje za procjenu simptoma anksioznosti kod starijih osoba koje žive u nekoliko većih gradova države Rajasthan u Indiji. Metode: Studija je provedena od travnja 2020. do svibnja 2020. godine korištenjem online upitnika koji je mjerio razine anksioznosti među starijom populacijom (dob ≥ 65 godina) koja živi u zajednici a putem skale GAD-7 (GAD-7 skala anksioznosti). Odgovori su dobiveni od 162 sudionika. Podaci su analizirani pomoću Chi-kvadrat testa i logističke regresije. Razina statističke značajnosti zadržana je na vrijednosti p <0,05. Rezultati: Otprilike 69,14% sudionika pripadalo je dobnoj skupini od 65 do 74 godine; od kojih su 61,72% bili muškarci. Štoviše, do 82,72% sudionika patilo je od jedne ili više kroničnih medicinskih bolesti. Na temelju ocjena GAD-7, 30,25%, 12,35%, odnosno 6,17% ispitanika patilo je od blagog, umjerenog i teškog oblika anksioznosti. Nakon davanja ocjene ≥ 5 kao granične vrijednosti za GAD-7 ljestvicu, 48,77% starijih sudionika imalo je simptome anksioznosti što ukazuje na potrebu daljnje procjene. U ispitanika sa simptomima anksioznosti uočena je značajna povezanost s dobi (p = 0,00), spolom (p = 0,04) i zonom boravka (p = 0,00). S druge strane, nije uočena značajnija povezanost prisutnosti kroničnih medicinskih bolesti poput dijabetesa, hipertenzije, KOPB-a itd. sa simptomima anksioznosti (p = 0,77). Zaključak: Ova studija je otkrila visoku prevalenciju simptoma anksioznosti među starijom populacijom tijekom karantene izazvane pandemijom COVID-19. Preporučujemo pripremu unaprijed planirane strategije za ranu identifikaciju ranjivih starijih osoba u zajednici koje imaju veći rizik razvoja anksioznog poremećaja u ovom stresnom razdoblju

A novel Plasmodium falciparum rhoptry associated adhesin mediates erythrocyte invasion through the sialic-acid dependent pathway

Erythrocyte invasion by Plasmodium falciparum merozoites is central to blood-stage infection and malaria pathogenesis. This intricate process is coordinated by multiple parasite adhesins that bind erythrocyte receptors and mediate invasion through several alternate pathways. P. falciparum expresses 2700 genes during the blood-stages, of which the identity and function of many remains unknown. Here, we have identified and characterized a novel P. falciparum rhoptry associated adhesin (PfRA) that mediates erythrocyte invasion through the sialic-acid dependent pathway. PfRA appears to play a significant functional role as it is conserved across different Plasmodium species. It is localized in the rhoptries and further translocated to the merozoite surface. Both native and recombinant PfRA specifically bound erythrocytes in a sialic-acid dependent, chymotrypsin and trypsin resistant manner, which was abrogated by PfRA antibodies confirming a role in erythrocyte invasion. PfRA antibodies inhibited erythrocyte invasion and in combination with antibodies against other parasite ligands produced an additive inhibitory effect, thus validating its important role in erythrocyte invasion. We have thus identified a novel P. falciparum adhesin that binds with a sialic acid containing erythrocyte receptor. Our observations substantiate the strategy to block P. falciparum erythrocyte invasion by simultaneously targeting multiple conserved merozoite antigens involved in alternate invasion pathways